Contribution: organisation=mat hyplab,FACT2=0.5 PY - 2010 Y1 - 2010 M3 - Article SP - 18 EP - 20 JO - Fluid Finland JF - Fluid Finland SN - 1458-7599 IS - 2/2010 ER - TY - JOUR T1 - 10 kA Joints for HTS Roebel Cables AU - Murtomaeki, Jaakko Samuel AU - Kirby, Glyn AU - van Nugteren, Jeroen AU - Contat, Pierre Antoine AU - Fleiter, Jerome AU - De Frutos, Oscar Sacristan AU - Pincot, Francois Olivier AU - DeRijk, Gijs AU - Rossi, Lucio AU - Ruuskanen, Janne AU - Stenvall, Antti AU - Wolf, Felix PY - 2018 Y1 - 2018 N2 - Future HTS high field magnets using multi-tape HTS cables need 10 kA low resistance connections. The connections are needed between the poles of the magnets and at the terminals in a wide operating temperature range, from 1.9-85 K. The EuCARD WP10 Future Magnets collaboration aims at testing HTS based Roebel cables in an accelerator magnet. Usually, LTS cables are jointed inside a relatively short soldered block. Powering tests at CERN have highlighted excess heating of a joint following classical LTS joint design. The HTS Roebel cables are assembled from REBCO coated conductor tapes in a transposed configuration. Due to this, the tapes surface the cable at an angle with the cable axis. A low-resistance joint requires a sufficiently large interface area for each tape. Within one twist pitch length, each tape is located at the surface of the cable over a relatively small non-constant area. This geometry prevents making a well-controlled joint in a compact length along the cable. This paper presents a compact joint configuration for the Roebel cable overcoming these practical challenges. A new joint called fin-block is designed. The joint resistance is estimated computationally. Finally the test results as a function of current and temperature are presented. AB - Future HTS high field magnets using multi-tape HTS cables need 10 kA low resistance connections. The connections are needed between the poles of the magnets and at the terminals in a wide operating temperature range, from 1.9-85 K. The EuCARD WP10 Future Magnets collaboration aims at testing HTS based Roebel cables in an accelerator magnet. Usually, LTS cables are jointed inside a relatively short soldered block. Powering tests at CERN have highlighted excess heating of a joint following classical LTS joint design. The HTS Roebel cables are assembled from REBCO coated conductor tapes in a transposed configuration. Due to this, the tapes surface the cable at an angle with the cable axis. A low-resistance joint requires a sufficiently large interface area for each tape. Within one twist pitch length, each tape is located at the surface of the cable over a relatively small non-constant area. This geometry prevents making a well-controlled joint in a compact length along the cable. This paper presents a compact joint configuration for the Roebel cable overcoming these practical challenges. A new joint called fin-block is designed. The joint resistance is estimated computationally. Finally the test results as a function of current and temperature are presented. KW - Cables and current leads KW - Heating systems KW - High-temperature superconductors KW - HTS Magnets KW - Pressure Measurement KW - Resistance KW - Resistance measurement KW - Soldering KW - Superconducting cables KW - Superconducting magnets KW - Superconducting Magnets KW - Temperature measurement U2 - 10.1109/TASC.2018.2804951 DO - 10.1109/TASC.2018.2804951 M3 - Article VL - 28 JO - IEEE Transactions on Applied Superconductivity JF - IEEE Transactions on Applied Superconductivity SN - 1051-8223 IS - 3 ER - TY - JOUR T1 - (16) Psyche T2 - A mesosiderite-like asteroid? AU - Viikinkoski, M. AU - Vernazza, P. AU - Hanuš, J. AU - Le Coroller, H. AU - Tazhenova, K. AU - Carry, B. AU - Marsset, M. AU - Drouard, A. AU - Marchis, F. AU - Fetick, R. AU - Fusco, T. AU - Ďurech, J. AU - Birlan, M. AU - Berthier, J. AU - Bartczak, P. AU - Dumas, C. AU - Castillo-Rogez, J. AU - Cipriani, F. AU - Colas, F. AU - Ferrais, M. AU - Grice, J. AU - Jehin, E. AU - Jorda, L. AU - Kaasalainen, M. AU - Kryszczynska, A. AU - Lamy, P. AU - Marciniak, A. AU - Michalowski, T. AU - Michel, P. AU - Pajuelo, M. AU - Podlewska-Gaca, E. AU - Santana-Ros, T. AU - Tanga, P. AU - Vachier, F. AU - Vigan, A. AU - Warner, B. AU - Witasse, O. AU - Yang, B. PY - 2018/11/1 Y1 - 2018/11/1 N2 - Context. Asteroid (16) Psyche is the target of the NASA Psyche mission. It is considered one of the few main-belt bodies that could be an exposed proto-planetary metallic core and that would thus be related to iron meteorites. Such an association is however challenged by both its near- and mid-infrared spectral properties and the reported estimates of its density. Aims. Here, we aim to refine the density of (16) Psyche to set further constraints on its bulk composition and determine its potential meteoritic analog. Methods. We observed (16) Psyche with ESO VLT/SPHERE/ZIMPOL as part of our large program (ID 199.C-0074). We used the high angular resolution of these observations to refine Psyche's three-dimensional (3D) shape model and subsequently its density when combined with the most recent mass estimates. In addition, we searched for potential companions around the asteroid. Results. We derived a bulk density of 3.99 ± 0.26 ± cm-3 for Psyche. While such density is incompatible at the 3-sigma level with any iron meteorites (∼7.8 ± cm-3), it appears fully consistent with that of stony-iron meteorites such as mesosiderites (density ∼4.25 ± cm-3). In addition, we found no satellite in our images and set an upper limit on the diameter of any non-detected satellite of 1460 ± 200 m at 150 km from Psyche (0.2% × RHill, the Hill radius) and 800 ± 200 m at 2000 km (3% × RHill). Conclusions. Considering that the visible and near-infrared spectral properties of mesosiderites are similar to those of Psyche, there is merit to a long-published initial hypothesis that Psyche could be a plausible candidate parent body for mesosiderites. AB - Context. Asteroid (16) Psyche is the target of the NASA Psyche mission. It is considered one of the few main-belt bodies that could be an exposed proto-planetary metallic core and that would thus be related to iron meteorites. Such an association is however challenged by both its near- and mid-infrared spectral properties and the reported estimates of its density. Aims. Here, we aim to refine the density of (16) Psyche to set further constraints on its bulk composition and determine its potential meteoritic analog. Methods. We observed (16) Psyche with ESO VLT/SPHERE/ZIMPOL as part of our large program (ID 199.C-0074). We used the high angular resolution of these observations to refine Psyche's three-dimensional (3D) shape model and subsequently its density when combined with the most recent mass estimates. In addition, we searched for potential companions around the asteroid. Results. We derived a bulk density of 3.99 ± 0.26 ± cm-3 for Psyche. While such density is incompatible at the 3-sigma level with any iron meteorites (∼7.8 ± cm-3), it appears fully consistent with that of stony-iron meteorites such as mesosiderites (density ∼4.25 ± cm-3). In addition, we found no satellite in our images and set an upper limit on the diameter of any non-detected satellite of 1460 ± 200 m at 150 km from Psyche (0.2% × RHill, the Hill radius) and 800 ± 200 m at 2000 km (3% × RHill). Conclusions. Considering that the visible and near-infrared spectral properties of mesosiderites are similar to those of Psyche, there is merit to a long-published initial hypothesis that Psyche could be a plausible candidate parent body for mesosiderites. KW - Methods: observational KW - Minor planets, asteroids: general KW - Minor planets, asteroids: individual: (16) Psyche KW - Techniques: high angular resolution U2 - 10.1051/0004-6361/201834091 DO - 10.1051/0004-6361/201834091 M3 - Article VL - 619 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - L3 ER - TY - JOUR T1 - 3D shape of asteroid (6) Hebe from VLT/SPHERE imaging T2 - Implications for the origin of ordinary H chondrites AU - Marsset, M. AU - Carry, B. AU - Dumas, C. AU - Hanuš, J. AU - Viikinkoski, M. AU - Vernazza, P. AU - Müller, T. G. AU - Delbo, M. AU - Jehin, E. AU - Gillon, M. AU - Grice, J. AU - Yang, B. AU - Fusco, T. AU - Berthier, J. AU - Sonnett, S. AU - Kugel, F. AU - Caron, J. AU - Behrend, R. PY - 2017/8/1 Y1 - 2017/8/1 N2 - Context. The high-angular-resolution capability of the new-generation ground-based adaptive-optics camera SPHERE at ESO VLT allows us to assess, for the very first time, the cratering record of medium-sized (D ∼ 100-200 km) asteroids from the ground, opening the prospect of a new era of investigation of the asteroid belt's collisional history. Aims. We investigate here the collisional history of asteroid (6) Hebe and challenge the idea that Hebe may be the parent body of ordinary H chondrites, the most common type of meteorites found on Earth (∼34% of the falls). Methods. We observed Hebe with SPHERE as part of the science verification of the instrument. Combined with earlier adaptive-optics images and optical light curves, we model the spin and three-dimensional (3D) shape of Hebe and check the consistency of the derived model against available stellar occultations and thermal measurements. Results. Our 3D shape model fits the images with sub-pixel residuals and the light curves to 0.02 mag. The rotation period (7.274 47 h), spin (ECJ2000 λ, β of 343°, +47°), and volume-equivalent diameter (193 ± 6 km) are consistent with previous determinations and thermophysical modeling. Hebe's inferred density is 3.48 ± 0.64 g cm-3, in agreement with an intact interior based on its H-chondrite composition. Using the 3D shape model to derive the volume of the largest depression (likely impact crater), it appears that the latter is significantly smaller than the total volume of close-by S-type H-chondrite-like asteroid families. Conclusions. Our results imply that (6) Hebe is not the most likely source of H chondrites. Over the coming years, our team will collect similar high-precision shape measurements with VLT/SPHERE for ∼40 asteroids covering the main compositional classes, thus providing an unprecedented dataset to investigate the origin and collisional evolution of the asteroid belt. AB - Context. The high-angular-resolution capability of the new-generation ground-based adaptive-optics camera SPHERE at ESO VLT allows us to assess, for the very first time, the cratering record of medium-sized (D ∼ 100-200 km) asteroids from the ground, opening the prospect of a new era of investigation of the asteroid belt's collisional history. Aims. We investigate here the collisional history of asteroid (6) Hebe and challenge the idea that Hebe may be the parent body of ordinary H chondrites, the most common type of meteorites found on Earth (∼34% of the falls). Methods. We observed Hebe with SPHERE as part of the science verification of the instrument. Combined with earlier adaptive-optics images and optical light curves, we model the spin and three-dimensional (3D) shape of Hebe and check the consistency of the derived model against available stellar occultations and thermal measurements. Results. Our 3D shape model fits the images with sub-pixel residuals and the light curves to 0.02 mag. The rotation period (7.274 47 h), spin (ECJ2000 λ, β of 343°, +47°), and volume-equivalent diameter (193 ± 6 km) are consistent with previous determinations and thermophysical modeling. Hebe's inferred density is 3.48 ± 0.64 g cm-3, in agreement with an intact interior based on its H-chondrite composition. Using the 3D shape model to derive the volume of the largest depression (likely impact crater), it appears that the latter is significantly smaller than the total volume of close-by S-type H-chondrite-like asteroid families. Conclusions. Our results imply that (6) Hebe is not the most likely source of H chondrites. Over the coming years, our team will collect similar high-precision shape measurements with VLT/SPHERE for ∼40 asteroids covering the main compositional classes, thus providing an unprecedented dataset to investigate the origin and collisional evolution of the asteroid belt. KW - asteroids: individual: (6) Hebe KW - Meteorites KW - meteoroids KW - meteors KW - Minor planets KW - Techniques: high angular resolution U2 - 10.1051/0004-6361/201731021 DO - 10.1051/0004-6361/201731021 M3 - Article VL - 604 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A64 ER - TY - JOUR T1 - Absolute radiometric calibration of ALS intensity data: Effects on accuracy and target classification AU - Kaasalainen, Sanna AU - Pyysalo, Ulla AU - Krooks, Anssi AU - Vain, Ants AU - Kukko, Antero AU - Hyyppä, Juha AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.3390/s111110586 DO - 10.3390/s111110586 M3 - Article VL - 11 SP - 10586 EP - 10602 JO - Sensors JF - Sensors SN - 1424-8220 IS - 11 ER - TY - JOUR T1 - A category theoretical interpretation of discretization in Galerkin finite element method AU - Lahtinen, Valtteri AU - Stenvall, Antti PY - 2020 Y1 - 2020 N2 - The Galerkin finite element method (FEM) is used widely in finding approximative solutions to field problems in engineering and natural sciences. When utilizing FEM, the field problem is said to be discretized. In this paper, we interpret discretization in FEM through category theory, unifying the concept of discreteness in FEM with that of discreteness in other fields of mathematics, such as topology. This reveals structural properties encoded in this concept: we propose that discretization is a dagger mono with a discrete domain in the category of Hilbert spaces made concrete over the category of vector spaces. Moreover, we discuss parallel decomposability of discretization, and through examples, connect it to different FEM formulations and choices of basis functions. AB - The Galerkin finite element method (FEM) is used widely in finding approximative solutions to field problems in engineering and natural sciences. When utilizing FEM, the field problem is said to be discretized. In this paper, we interpret discretization in FEM through category theory, unifying the concept of discreteness in FEM with that of discreteness in other fields of mathematics, such as topology. This reveals structural properties encoded in this concept: we propose that discretization is a dagger mono with a discrete domain in the category of Hilbert spaces made concrete over the category of vector spaces. Moreover, we discuss parallel decomposability of discretization, and through examples, connect it to different FEM formulations and choices of basis functions. KW - Category theory KW - Discretization KW - Engineering KW - Finite element method KW - Mathematical modeling U2 - 10.1007/s00209-020-02456-1 DO - 10.1007/s00209-020-02456-1 M3 - Article JO - MATHEMATISCHE ZEITSCHRIFT JF - MATHEMATISCHE ZEITSCHRIFT SN - 0025-5874 ER - TY - JOUR T1 - Acceleration of the rotation of asteroid 1862 Apollo by radiation torques AU - Kaasalainen, M. AU - Durech, J. AU - Warner, B. AU - Krugky, Y. AU - Gaftonyuk, N. N1 - Contribution: organisation=mat,FACT1=1 PY - 2007 Y1 - 2007 U2 - 10.1038/nature05614 DO - 10.1038/nature05614 M3 - Article VL - 446 SP - 420 EP - 422 JO - Nature JF - Nature SN - 0028-0836 ER - TY - JOUR T1 - A characterization of level-continuous fuzzy numbers AU - Kaleva, Osmo N1 - Published 16 December 2012

Contribution: organisation=mat,FACT1=1

Publisher name: Elsevier BV North-Holland PY - 2012 Y1 - 2012 U2 - 10.1016/j.fss.2012.07.002 DO - 10.1016/j.fss.2012.07.002 M3 - Article VL - 209 SP - 84 EP - 88 JO - Fuzzy Sets and Systems JF - Fuzzy Sets and Systems SN - 0165-0114 ER - TY - JOUR T1 - A comparison of confluence and ample sets in probabilistic and non-probabilistic branching time AU - Hansen, Henri AU - Timmer, Mark N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-05-31

Publisher name: Elsevier PY - 2014 Y1 - 2014 U2 - 10.1016/j.tcs.2013.07.014 DO - 10.1016/j.tcs.2013.07.014 M3 - Article VL - 528 SP - 103 EP - 123 JO - Theoretical Computer Science JF - Theoretical Computer Science SN - 0304-3975 ER - TY - JOUR T1 - ADAM T2 - A general method for using various data types in asteroid reconstruction AU - Viikinkoski, Matti AU - Kaasalainen, Mikko AU - Durech, Josef PY - 2015/4/1 Y1 - 2015/4/1 N2 - We introduce ADAM, the All-Data Asteroid Modelling algorithm. ADAM is simple and universal since it handles all disk-resolved data types (adaptive optics or other images, interferometry, and range-Doppler radar data) in a uniform manner via the 2D Fourier transform, enabling fast convergence in model optimization. The resolved data can be combined with disk-integrated data (photometry). In the reconstruction process, the difference between each data type is only a few code lines defining the particular generalized projection from 3D onto a 2D image plane. Occultation timings can be included as sparse silhouettes, and thermal infrared data are efficiently handled with an approximate algorithm that is sufficient in practice because of the dominance of the high-contrast (boundary) pixels over the low-contrast (interior) pixels. This is of particular importance to the raw ALMA data that can be directly handled by ADAM without having to construct the standard image. We study the reliability of the inversion, using the independent shape supports of function series and control-point surfaces. When other data are lacking, one can carry out fast non-convex lightcurve-only inversions, but any shape models resulting from it should only be taken as illustrative large-scale models. AB - We introduce ADAM, the All-Data Asteroid Modelling algorithm. ADAM is simple and universal since it handles all disk-resolved data types (adaptive optics or other images, interferometry, and range-Doppler radar data) in a uniform manner via the 2D Fourier transform, enabling fast convergence in model optimization. The resolved data can be combined with disk-integrated data (photometry). In the reconstruction process, the difference between each data type is only a few code lines defining the particular generalized projection from 3D onto a 2D image plane. Occultation timings can be included as sparse silhouettes, and thermal infrared data are efficiently handled with an approximate algorithm that is sufficient in practice because of the dominance of the high-contrast (boundary) pixels over the low-contrast (interior) pixels. This is of particular importance to the raw ALMA data that can be directly handled by ADAM without having to construct the standard image. We study the reliability of the inversion, using the independent shape supports of function series and control-point surfaces. When other data are lacking, one can carry out fast non-convex lightcurve-only inversions, but any shape models resulting from it should only be taken as illustrative large-scale models. KW - Methods: analytical KW - Methods: numerical KW - Minor planets, asteroids: general KW - Minor planets, asteroids: individual: 2000 ET70 KW - Minor planets, asteroids: individual: Daphne UR - http://www.scopus.com/inward/record.url?scp=84925251323&partnerID=8YFLogxK U2 - 10.1051/0004-6361/201425259 DO - 10.1051/0004-6361/201425259 M3 - Article VL - 576 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A8 ER - TY - JOUR T1 - Adaptive mobile tracking in unknown non-line-of-sight conditions with application to digital TV networks AU - Chen, L. AU - Piche, R. AU - Kuusniemi, H. AU - Chen, R. N1 - Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2014-05-25

Publisher name: Springer PY - 2014 Y1 - 2014 U2 - 10.1186/1687-6180-2014-22 DO - 10.1186/1687-6180-2014-22 M3 - Article VL - 2014 JO - Eurasip Journal on Advances in Signal Processing JF - Eurasip Journal on Advances in Signal Processing SN - 1687-6172 M1 - UNSP 22 ER - TY - JOUR T1 - Adaptive optics and lightcurve data of asteroids T2 - Twenty shape models and information content analysis AU - Viikinkoski, M. AU - Hanuš, J. AU - Kaasalainen, M. AU - Marchis, F. AU - Ďurech, J. PY - 2017/11/1 Y1 - 2017/11/1 N2 - We present shape models and volume estimates of twenty asteroids based on relative photometry and adaptive optics images. We discuss error estimation and the effects of myopic deconvolution on shape solutions. For further analysis of the information capacities of data sources, we also present and discuss ambiguity and uniqueness results for the reconstruction of nonconvex shapes from photometry. AB - We present shape models and volume estimates of twenty asteroids based on relative photometry and adaptive optics images. We discuss error estimation and the effects of myopic deconvolution on shape solutions. For further analysis of the information capacities of data sources, we also present and discuss ambiguity and uniqueness results for the reconstruction of nonconvex shapes from photometry. KW - Instrumentation: adaptive optics KW - Methods: analytical KW - Methods: numerical KW - Minor planets, asteroids: general KW - Techniques: photometric U2 - 10.1051/0004-6361/201731456 DO - 10.1051/0004-6361/201731456 M3 - Article VL - 607 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A117 ER - TY - JOUR T1 - Advanced boundary electrode modeling for tES and parallel tES/EEG AU - Pursiainen, S. AU - Agsten, B. AU - Wagner, S. AU - Wolters, C. H. PY - 2017 Y1 - 2017 N2 - This paper explores advanced electrode modeling in the context of separate and parallel transcranial electrical stimulation (tES) and electroencephalography (EEG) measurements.We focus on boundary condition based approaches that do not necessitate adding auxiliary elements, e.g. sponges, to the computational domain. In particular, we investigate the complete electrode model (CEM) which incorporates a detailed description of the skin-electrode interface including its contact surface, impedance and normal current distribution. The CEM can be applied for both tES and EEG electrodes which is advantageous when a parallel system is used. In comparison to the CEM, we test two important reduced approaches: the gap model (GAP) and the point electrode model (PEM). We aim to find out the differences of these approaches for a realistic numerical setting based on the stimulation of the auditory cortex. The results obtained suggest, among other things, that GAP and GAP/PEM are sufficiently accurate for the practical application of tES and parallel tES/EEG, respectively. Differences between CEM and GAP were observed mainly in the skin compartment, where only CEM explains the heating effects characteristic to tES. AB - This paper explores advanced electrode modeling in the context of separate and parallel transcranial electrical stimulation (tES) and electroencephalography (EEG) measurements.We focus on boundary condition based approaches that do not necessitate adding auxiliary elements, e.g. sponges, to the computational domain. In particular, we investigate the complete electrode model (CEM) which incorporates a detailed description of the skin-electrode interface including its contact surface, impedance and normal current distribution. The CEM can be applied for both tES and EEG electrodes which is advantageous when a parallel system is used. In comparison to the CEM, we test two important reduced approaches: the gap model (GAP) and the point electrode model (PEM). We aim to find out the differences of these approaches for a realistic numerical setting based on the stimulation of the auditory cortex. The results obtained suggest, among other things, that GAP and GAP/PEM are sufficiently accurate for the practical application of tES and parallel tES/EEG, respectively. Differences between CEM and GAP were observed mainly in the skin compartment, where only CEM explains the heating effects characteristic to tES. KW - Boundary conditions KW - Brain modeling KW - Complete electrode model (CEM) KW - Computational modeling KW - Electric potential KW - Electrodes KW - Electroencephalography KW - Electroencephalography (EEG) electrode modeling KW - Finite element method (FEM). KW - Skin KW - Transcranial electrical stimulation (tES) U2 - 10.1109/TNSRE.2017.2748930 DO - 10.1109/TNSRE.2017.2748930 M3 - Article VL - 26 SP - 37 EP - 44 JO - IEEE Transactions on Neural Systems and Rehabilitation Engineering JF - IEEE Transactions on Neural Systems and Rehabilitation Engineering SN - 1534-4320 IS - 1 ER - TY - JOUR T1 - A Feedforward Controller for Distributed Parameter Systems AU - Pohjolainen, Seppo PY - 1981 Y1 - 1981 N2 - A feedforward controller is introduced for an important class of distributed parameter systems. The purpose of the control is to regulate the outputs of the system in spite of some perturbations. The theory presented is clarified with an example. AB - A feedforward controller is introduced for an important class of distributed parameter systems. The purpose of the control is to regulate the outputs of the system in spite of some perturbations. The theory presented is clarified with an example. U2 - 10.1080/00207178108922521 DO - 10.1080/00207178108922521 M3 - Article VL - 34 SP - 173 EP - 184 JO - International Journal of Control JF - International Journal of Control SN - 0020-7179 IS - 1 ER - TY - JOUR T1 - A fractional representation approach to the robust regulation problem for SISO systems AU - Laakkonen, P. AU - Quadrat, A. PY - 2017/5/1 Y1 - 2017/5/1 N2 - The purpose of this article is to develop a new approach to the robust regulation problem for plants which do not necessarily admit coprime factorizations. The approach is purely algebraic and allows us dealing with a very general class of systems in a unique simple framework. We formulate the famous internal model principle in a form suitable for plants defined by fractional representations which are not necessarily coprime factorizations. By using the internal model principle, we are able to give necessary and sufficient solvability conditions for the robust regulation problem and to parameterize all robustly regulating controllers. AB - The purpose of this article is to develop a new approach to the robust regulation problem for plants which do not necessarily admit coprime factorizations. The approach is purely algebraic and allows us dealing with a very general class of systems in a unique simple framework. We formulate the famous internal model principle in a form suitable for plants defined by fractional representations which are not necessarily coprime factorizations. By using the internal model principle, we are able to give necessary and sufficient solvability conditions for the robust regulation problem and to parameterize all robustly regulating controllers. KW - Fractional representation approach KW - Linear systems KW - Robust regulation U2 - 10.1016/j.sysconle.2017.02.006 DO - 10.1016/j.sysconle.2017.02.006 M3 - Article VL - 103 SP - 32 EP - 37 JO - Systems and Control Letters JF - Systems and Control Letters SN - 0167-6911 ER - TY - JOUR T1 - A Framework for Bayesian Receiver Autonomous Integrity Monitoring in Urban Navigation AU - Pesonen, Henri N1 - ei ut-numeroa 26.4.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Article VL - 58 SP - 229 EP - 240 JO - Navigation JF - Navigation SN - 0028-1522 IS - 3 ER - TY - JOUR T1 - A general framework for island systems AU - Foldes, S. AU - Horváth, Eszter K. AU - Radeleczki, Sándor AU - Waldhauser, Tamás PY - 2015 Y1 - 2015 N2 - The notion of an island defined on a rectangular board is an elementary combinatorial concept that occurred first in [3]. Results of [3] were starting points for investigations exploring several variations and various aspects of this notion. In this paper we introduce a general framework for islands that subsumes all earlier studied concepts of islands on finite boards, moreover we show that the prime implicants of a Boolean function, the formal concepts of a formal context, convex subgraphs of a simple graph, and some particular subsets of a projective plane also fit into this framework. We axiomatize those cases where islands have the property of being pairwise comparable or disjoint, or they are distant, introducing the notion of a connective island domain and of a proximity domain, respectively. In the general case the maximal systems of islands are characterised by using the concept of an admissible system. We also characterise all possible island systems in the case of connective island domains and proximity domains. AB - The notion of an island defined on a rectangular board is an elementary combinatorial concept that occurred first in [3]. Results of [3] were starting points for investigations exploring several variations and various aspects of this notion. In this paper we introduce a general framework for islands that subsumes all earlier studied concepts of islands on finite boards, moreover we show that the prime implicants of a Boolean function, the formal concepts of a formal context, convex subgraphs of a simple graph, and some particular subsets of a projective plane also fit into this framework. We axiomatize those cases where islands have the property of being pairwise comparable or disjoint, or they are distant, introducing the notion of a connective island domain and of a proximity domain, respectively. In the general case the maximal systems of islands are characterised by using the concept of an admissible system. We also characterise all possible island systems in the case of connective island domains and proximity domains. KW - Admissible system KW - CD-independent and CDW-independent sets KW - Connected subgraph KW - Convex subgraph KW - Distant system KW - Formal concept KW - Height function KW - Island domain KW - Island system KW - Point-to-set proximity relation KW - Prime implicant KW - Projective plane KW - Proximity domain UR - http://www.scopus.com/inward/record.url?scp=84938827353&partnerID=8YFLogxK U2 - 10.14232/actasm-013-279-7 DO - 10.14232/actasm-013-279-7 M3 - Article VL - 81 SP - 3 EP - 24 JO - Acta Universitatis Szegediensis: Acta Scientiarum Mathematicarum JF - Acta Universitatis Szegediensis: Acta Scientiarum Mathematicarum SN - 0001-6969 IS - 1-2 ER - TY - JOUR T1 - A Hyperbolic Dirac Operator and its Kernels AU - Eriksson, Sirkka-Liisa N1 - Taylor&Francis Online first: Forthcoming articles 12.10.2011.Poistettu Portfolio13:sta tupla r=1849.

Contribution: organisation=mat,FACT1=1 PY - 2013 Y1 - 2013 U2 - 10.1080/17476933.2011.620096 DO - 10.1080/17476933.2011.620096 M3 - Article VL - 58 SP - 767 EP - 781 JO - Complex Variables and Elliptic Equations JF - Complex Variables and Elliptic Equations SN - 1747-6933 IS - 6 ER - TY - JOUR T1 - A Lyapunov approach to strong stability of semigroups AU - Paunonen, Lassi AU - Zwart, Hans N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-07-29

Publisher name: Elsevier PY - 2013 Y1 - 2013 N2 - In this paper we present Lyapunov based proofs for the well-known Arendt-Batty-Lyubich-Vu Theorem for strongly continuous and discrete semigroups. We also study the spectral properties of the limit isometric groups used in the proofs. AB - In this paper we present Lyapunov based proofs for the well-known Arendt-Batty-Lyubich-Vu Theorem for strongly continuous and discrete semigroups. We also study the spectral properties of the limit isometric groups used in the proofs. U2 - 10.1016/j.sysconle.2013.05.001 DO - 10.1016/j.sysconle.2013.05.001 M3 - Article VL - 62 SP - 673 EP - 678 JO - Systems and Control Letters JF - Systems and Control Letters SN - 0167-6911 IS - 8 ER - TY - JOUR T1 - A Mean-Value Theorem for Some Eigenfunctions of the Laplace -Beltrami Operator on the Upper-Half Space AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.5186/aasfm.2011.3606 DO - 10.5186/aasfm.2011.3606 M3 - Article VL - 36 SP - 101 EP - 110 JO - Annales Academiae Scientiarum Fennicae-Mathematica JF - Annales Academiae Scientiarum Fennicae-Mathematica SN - 1239-629X ER - TY - JOUR T1 - A Mixed Finite Element Method to Solve the EEG Forward Problem AU - Vorwerk, J. AU - Engwer, C. AU - Pursiainen, S. AU - Wolters, C. H. PY - 2017/4/1 Y1 - 2017/4/1 N2 - Finite element methods have been shown to achieve high accuracies in numerically solving the EEG forward problem and they enable the realistic modeling of complex geometries and important conductive features such as anisotropic conductivities. To date, most of the presented approaches rely on the same underlying formulation, the continuous Galerkin (CG)-FEM. In this article, a novel approach to solve the EEG forward problem based on a mixed finite element method (Mixed-FEM) is introduced. To obtain the Mixed-FEM formulation, the electric current is introduced as an additional unknown besides the electric potential. As a consequence of this derivation, the Mixed-FEM is, by construction, current preserving, in contrast to the CG-FEM. Consequently, a higher simulation accuracy can be achieved in certain scenarios, e.g., when the diameter of thin insulating structures, such as the skull, is in the range of the mesh resolution. A theoretical derivation of the Mixed-FEM approach for EEG forward simulations is presented, and the algorithms implemented for solving the resulting equation systems are described. Subsequently, first evaluations in both sphere and realistic head models are presented, and the results are compared to previously introduced CG-FEM approaches. Additional visualizations are shown to illustrate the current preserving property of the Mixed-FEM. Based on these results, it is concluded that the newly presented Mixed-FEM can at least complement and in some scenarios even outperform the established CG-FEM approaches, which motivates a further evaluation of the Mixed-FEM for applications in bioelectromagnetism. AB - Finite element methods have been shown to achieve high accuracies in numerically solving the EEG forward problem and they enable the realistic modeling of complex geometries and important conductive features such as anisotropic conductivities. To date, most of the presented approaches rely on the same underlying formulation, the continuous Galerkin (CG)-FEM. In this article, a novel approach to solve the EEG forward problem based on a mixed finite element method (Mixed-FEM) is introduced. To obtain the Mixed-FEM formulation, the electric current is introduced as an additional unknown besides the electric potential. As a consequence of this derivation, the Mixed-FEM is, by construction, current preserving, in contrast to the CG-FEM. Consequently, a higher simulation accuracy can be achieved in certain scenarios, e.g., when the diameter of thin insulating structures, such as the skull, is in the range of the mesh resolution. A theoretical derivation of the Mixed-FEM approach for EEG forward simulations is presented, and the algorithms implemented for solving the resulting equation systems are described. Subsequently, first evaluations in both sphere and realistic head models are presented, and the results are compared to previously introduced CG-FEM approaches. Additional visualizations are shown to illustrate the current preserving property of the Mixed-FEM. Based on these results, it is concluded that the newly presented Mixed-FEM can at least complement and in some scenarios even outperform the established CG-FEM approaches, which motivates a further evaluation of the Mixed-FEM for applications in bioelectromagnetism. KW - EEG KW - forward problem KW - mixed finite element method KW - realistic head modeling KW - source analysis U2 - 10.1109/TMI.2016.2624634 DO - 10.1109/TMI.2016.2624634 M3 - Article VL - 36 SP - 930 EP - 941 JO - IEEE Transactions on Medical Imaging JF - IEEE Transactions on Medical Imaging SN - 0278-0062 IS - 4 M1 - 7731161 ER - TY - JOUR T1 - A Molecular Camera Gyroscope AU - Huttunen, Ville AU - Piche, Robert N1 - Ei UT-numeroa 14.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Tsentral'nyi Nauchno-Issledovatel'skii Institut Elektropribor PY - 2012 Y1 - 2012 M3 - Article VL - 77 SP - 69 EP - 81 JO - Giroskopiya I Navigatsiya JF - Giroskopiya I Navigatsiya SN - 0869-7035 ER - TY - JOUR T1 - A Monocular Camera Gyroscope AU - Huttunen, Ville AU - Piche, Robert N1 - Ei UT-numeroa 14.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: MAIK Nauka/Interperiodica distributed exclusively by Springer Science+Business Media LLC PY - 2012 Y1 - 2012 N2 - We present a method for tracking the 3-axis orientation of a monocular camera using orthogonal vanishing points detected in individual frames of a sequence of images. Robust and real-time vanishing point detection is done using a standard line segment detection method and an adaptive RANSAC algorithm. Vanishing points and corresponding vanishing directions found in consecutive frames are associated with each other to produce a sequence of orientation quaternions, which is processed by an extended Kalman filter. Experiments with a consumer-level, handheld mobile device indicate that the accuracy of the proposed method is comparable with those of consumer-grade inertial motion sensors. AB - We present a method for tracking the 3-axis orientation of a monocular camera using orthogonal vanishing points detected in individual frames of a sequence of images. Robust and real-time vanishing point detection is done using a standard line segment detection method and an adaptive RANSAC algorithm. Vanishing points and corresponding vanishing directions found in consecutive frames are associated with each other to produce a sequence of orientation quaternions, which is processed by an extended Kalman filter. Experiments with a consumer-level, handheld mobile device indicate that the accuracy of the proposed method is comparable with those of consumer-grade inertial motion sensors. U2 - 10.1134/S2075108712020046 DO - 10.1134/S2075108712020046 M3 - Article VL - 3 SP - 124 EP - 131 JO - Gyroscopy and Navigation JF - Gyroscopy and Navigation SN - 2075-1087 IS - 2 ER - TY - JOUR T1 - An Adaptive Derivative Free Method for Bayesian Posterior Approximation AU - Raitoharju, Matti AU - Ali-Löytty, Simo N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Electrical and Electronics Engineers IEEE PY - 2012 Y1 - 2012 N2 - In the Gaussian mixture approach a Bayesian posterior probability distribution function is approximated using a weighted sum of Gaussians. This work presents a novel method for generating a Gaussian mixture by splitting the prior taking the direction of maximum nonlinearity into account. The proposed method is computationally feasible and does not require analytical differentiation. Tests show that the method approximates the posterior better with fewer Gaussian components than existing methods. AB - In the Gaussian mixture approach a Bayesian posterior probability distribution function is approximated using a weighted sum of Gaussians. This work presents a novel method for generating a Gaussian mixture by splitting the prior taking the direction of maximum nonlinearity into account. The proposed method is computationally feasible and does not require analytical differentiation. Tests show that the method approximates the posterior better with fewer Gaussian components than existing methods. U2 - 10.1109/LSP.2011.2179800 DO - 10.1109/LSP.2011.2179800 M3 - Article VL - 19 SP - 87 EP - 90 JO - IEEE Signal Processing Letters JF - IEEE Signal Processing Letters SN - 1070-9908 IS - 2 M1 - 12436433 ER - TY - JOUR T1 - An algebraic study of Peterson´s Intermediate Syllogisms AU - Turunen, Esko N1 - Published online: 21 January 2014

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-04-29

Publisher name: Springer PY - 2014 Y1 - 2014 U2 - 10.1007/s00500-013-1216-2 DO - 10.1007/s00500-013-1216-2 M3 - Article SP - 1 EP - 14 JO - Soft Computing JF - Soft Computing SN - 1432-7643 ER - TY - JOUR T1 - Analysing and Improving Student's Mathematics Skills using ICT-tools AU - Pohjolainen, Seppo AU - Nykänen, Ossi AU - Venho, Janne AU - Kangas, Jussi PY - 2018/1/8 Y1 - 2018/1/8 N2 - In this paper the supportive actions taken at Tampere University of Technology (TUT) for the first year students in engineering mathematics are discussed. The measures include Basic Skill’s Test (BST), Mathematics Remedial Instruction (MRI), and student profiling based on students' attitudes on learning. Specially, we describe how MRI was implemented in Math-Bridge and carried out at TUT. The effects of MRI for different learner groups using success indicators, log file analysis, and statistical methods are presented and clarified using data visualization. AB - In this paper the supportive actions taken at Tampere University of Technology (TUT) for the first year students in engineering mathematics are discussed. The measures include Basic Skill’s Test (BST), Mathematics Remedial Instruction (MRI), and student profiling based on students' attitudes on learning. Specially, we describe how MRI was implemented in Math-Bridge and carried out at TUT. The effects of MRI for different learner groups using success indicators, log file analysis, and statistical methods are presented and clarified using data visualization. KW - Science education KW - Teacher education KW - Biology Education KW - Environmental education U2 - 10.29333/ejmste/81869 DO - 10.29333/ejmste/81869 M3 - Article VL - 14 SP - 1221 EP - 1227 JO - EURASIA JOURNAL OF MATHEMATICS, SCIENCE & TECHNOLOGY EDUCATION JF - EURASIA JOURNAL OF MATHEMATICS, SCIENCE & TECHNOLOGY EDUCATION SN - 1305-8223 IS - 4 M1 - 14(4) ER - TY - JOUR T1 - Analysis of common rail pressure signal of dual-fuel large industrial engine for identification of injection duration of pilot diesel injectors AU - Krogerus, Tomi AU - Hyvönen, Mika AU - Huhtala, Kalevi PY - 2018/3 Y1 - 2018/3 N2 - In this paper, we address the problem of identification of injection duration of common rail (CR) diesel pilot injectors of dual-fuel engines. In these pilot injectors, the injected volume is small and the repeatability of injections and identification of drifts of injectors are important factors, which need to be taken into account in order to achieve good repeatability (shot-to-shot with every cylinder) and therefore a well-balanced engine and furthermore reduced overall wear. This information can then be used for calibration and diagnostics purposes to guarantee engine longevity facilitated by consistent operating conditions throughout the life of the unit. A diagnostics method based on analysis of CR pressure with experimental results is presented in this paper. Using the developed method, the relative duration of injection events can be identified for multiple injectors. We use the phenomenon of drop in rail pressure due to an injection event as a feature of the injection process. The method is based on filtered CR pressure data during and after the injection event. First, the pressure signal during injection is extracted after control of each injection event. After that, the signal is normalized and filtered. Then a derivative of the filtered signal is calculated. Change in the derivative of the filtered signal larger than a predefined threshold indicates an injection event that can be detected and its relative duration can be identified. We present the experimental results and demonstrate the efficacy of the proposed methods using two differenttypes of pressure sensors. We are able to properly identify a change of ≥10 μs (2%, 500 μs) in injection time. This shows that the developed method detects drifts in injection duration and the magnitude of drift. This information can be used for adaptive control of injection duration, so that finally the injected fuel volume is the same as the original. AB - In this paper, we address the problem of identification of injection duration of common rail (CR) diesel pilot injectors of dual-fuel engines. In these pilot injectors, the injected volume is small and the repeatability of injections and identification of drifts of injectors are important factors, which need to be taken into account in order to achieve good repeatability (shot-to-shot with every cylinder) and therefore a well-balanced engine and furthermore reduced overall wear. This information can then be used for calibration and diagnostics purposes to guarantee engine longevity facilitated by consistent operating conditions throughout the life of the unit. A diagnostics method based on analysis of CR pressure with experimental results is presented in this paper. Using the developed method, the relative duration of injection events can be identified for multiple injectors. We use the phenomenon of drop in rail pressure due to an injection event as a feature of the injection process. The method is based on filtered CR pressure data during and after the injection event. First, the pressure signal during injection is extracted after control of each injection event. After that, the signal is normalized and filtered. Then a derivative of the filtered signal is calculated. Change in the derivative of the filtered signal larger than a predefined threshold indicates an injection event that can be detected and its relative duration can be identified. We present the experimental results and demonstrate the efficacy of the proposed methods using two differenttypes of pressure sensors. We are able to properly identify a change of ≥10 μs (2%, 500 μs) in injection time. This shows that the developed method detects drifts in injection duration and the magnitude of drift. This information can be used for adaptive control of injection duration, so that finally the injected fuel volume is the same as the original. KW - Analysis KW - Dual-fuel engine KW - Diesel KW - Common rail KW - Injector KW - Rail pressure U2 - 10.1016/j.fuel.2017.11.152 DO - 10.1016/j.fuel.2017.11.152 M3 - Article VL - 216 SP - 1 EP - 9 JO - Fuel JF - Fuel SN - 0016-2361 ER - TY - JOUR T1 - Analysis of geometric primitives in quantitative structure models of tree stems AU - Åkerblom, Markku AU - Raumonen, Pasi AU - Kaasalainen, Mikko AU - Casella, Eric PY - 2015 Y1 - 2015 N2 - One way to model a tree is to use a collection of geometric primitives to represent the surface and topology of the stem and branches of a tree. The circular cylinder is often used as the geometric primitive, but it is not the only possible choice. We investigate various geometric primitives and modelling schemes, discuss their properties and give practical estimates for expected modelling errors associated with the primitives. We find that the circular cylinder is the most robust primitive in the sense of a well-bounded volumetric modelling error, even with noise and gaps in the data. Its use does not cause errors significantly larger than those with more complex primitives, while the latter are much more sensitive to data quality. However, in some cases, a hybrid approach with more complex primitives for the stem is useful. AB - One way to model a tree is to use a collection of geometric primitives to represent the surface and topology of the stem and branches of a tree. The circular cylinder is often used as the geometric primitive, but it is not the only possible choice. We investigate various geometric primitives and modelling schemes, discuss their properties and give practical estimates for expected modelling errors associated with the primitives. We find that the circular cylinder is the most robust primitive in the sense of a well-bounded volumetric modelling error, even with noise and gaps in the data. Its use does not cause errors significantly larger than those with more complex primitives, while the latter are much more sensitive to data quality. However, in some cases, a hybrid approach with more complex primitives for the stem is useful. KW - Biomass estimation KW - Error analysis KW - Shape fitting KW - Terrestrial laser scanning KW - Tree modelling UR - http://www.scopus.com/inward/record.url?scp=84937899906&partnerID=8YFLogxK U2 - 10.3390/rs70404581 DO - 10.3390/rs70404581 M3 - Article VL - 7 SP - 4581 EP - 4603 JO - Remote Sensing JF - Remote Sensing SN - 2072-4292 IS - 4 ER - TY - JOUR T1 - Analysis of Incidence Angle and Distance Effects on Terrestrial Laser Scanner Intensity: Search for Correction Methods AU - Kaasalainen, Sanna AU - Jaakkola, Anttoni AU - Kaasalainen, Mikko AU - Krooks, Anssi AU - Kukko, Antero N1 - Otsikko alunperin: Analysis of topographic and distance effects on TLS intensity: Search for correction methods

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.3390/rs3102207 DO - 10.3390/rs3102207 M3 - Article VL - 3 SP - 2207 EP - 2221 JO - Remote Sensing JF - Remote Sensing SN - 2072-4292 IS - 10 ER - TY - JOUR T1 - Analysis of the rotation period of asteroids (1865) Cerberus, (2100) Ra-Shalom, and (3103) Eger - search for the YORP effect AU - Durech, J. AU - Vokrouhlicky, D. AU - Baransky, A.R. AU - Breiter, S. AU - Burkhonov, O.A. AU - Cooney, W. AU - Fuller, V. AU - Gaftonyuk, N.M. AU - Gross, J. AU - Inasaridze, R.Ya. AU - Kaasalainen, Mikko AU - Krugly, Yu.N. AU - Kvaratshelia, O.I. AU - Litvinenko, E.A. AU - Macomber, B. AU - Marchis, F. AU - Molotov, I.E. AU - Oey, J. AU - Polishook, D. AU - Pollock, J. AU - Pravec, P. AU - Sarneczky, K. AU - Shevchenko, V.G. AU - Slyusarev, I. AU - Stephens, R. AU - Szabo, Gy. AU - Terrell, D. AU - Vachier, F. AU - Vanderplate, Z. AU - Viikinkoski, Matti AU - Warner, B.D. N1 - Contribution: organisation=mat,FACT1=1

Publisher name: EDP Sciences PY - 2012 Y1 - 2012 U2 - 10.1051/0004-6361/201219396 DO - 10.1051/0004-6361/201219396 M3 - Article VL - 547 SP - 9 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A10 ER - TY - JOUR T1 - Analytics of the impact of user involvement in the innovation process and its outcomes. Case study: Media-Enhanced Learning (MEL) Service AU - Still, Kaisa AU - Huhtamäki, Jukka AU - Isomursu, Minna AU - Lahti, Janne AU - Koskela-Huotari, Kaisa N1 - 4th World Conference on Educational Sciences, WCES 2012, 2-5 February 2012, Barcelona, Spain

Contribution: organisation=mat,FACT1=1

Publisher name: Elsevier PY - 2012 Y1 - 2012 U2 - 10.1016/j.sbspro.2012.05.370 DO - 10.1016/j.sbspro.2012.05.370 M3 - Article VL - 46 SP - 1740 EP - 1746 JO - Procedia: Social and Behavioral Sciences JF - Procedia: Social and Behavioral Sciences SN - 1877-0428 ER - TY - JOUR T1 - An architectural understanding of natural sway frequencies in trees AU - Jackson, T. AU - Shenkin, A. AU - Moore, J. AU - Bunce, A. AU - van Emmerik, T. AU - Kane, B. AU - Burcham, D. AU - James, K. AU - Selker, J. AU - Calders, K. AU - Origo, N. AU - Disney, M. AU - Burt, A. AU - Wilkes, P. AU - Raumonen, P. AU - Gonzalez de Tanago Menaca, J. AU - Lau, A. AU - Herold, M. AU - Goodman, R. C. AU - Fourcaud, T. AU - Malhi, Y. PY - 2019/6/28 Y1 - 2019/6/28 N2 - The relationship between form and function in trees is the subject of a longstanding debate in forest ecology and provides the basis for theories concerning forest ecosystem structure and metabolism. Trees interact with the wind in a dynamic manner and exhibit natural sway frequencies and damping processes that are important in understanding wind damage. Tree-wind dynamics are related to tree architecture, but this relationship is not well understood. We present a comprehensive view of natural sway frequencies in trees by compiling a dataset of field measurement spanning conifers and broadleaves, tropical and temperate forests. The field data show that a cantilever beam approximation adequately predicts the fundamental frequency of conifers, but not that of broadleaf trees. We also use structurally detailed tree dynamics simulations to test fundamental assumptions underpinning models of natural frequencies in trees. We model the dynamic properties of greater than 1000 trees using a finite-element approach based on accurate three-dimensional model trees derived from terrestrial laser scanning data. We show that (1) residual variation, the variation not explained by the cantilever beam approximation, in fundamental frequencies of broadleaf trees is driven by their architecture; (2) slender trees behave like a simple pendulum, with a single natural frequency dominating their motion, which makes them vulnerable to wind damage and (3) the presence of leaves decreases both the fundamental frequency and the damping ratio. These findings demonstrate the value of new three-dimensional measurements for understanding wind impacts on trees and suggest new directions for improving our understanding of tree dynamics from conifer plantations to natural forests. AB - The relationship between form and function in trees is the subject of a longstanding debate in forest ecology and provides the basis for theories concerning forest ecosystem structure and metabolism. Trees interact with the wind in a dynamic manner and exhibit natural sway frequencies and damping processes that are important in understanding wind damage. Tree-wind dynamics are related to tree architecture, but this relationship is not well understood. We present a comprehensive view of natural sway frequencies in trees by compiling a dataset of field measurement spanning conifers and broadleaves, tropical and temperate forests. The field data show that a cantilever beam approximation adequately predicts the fundamental frequency of conifers, but not that of broadleaf trees. We also use structurally detailed tree dynamics simulations to test fundamental assumptions underpinning models of natural frequencies in trees. We model the dynamic properties of greater than 1000 trees using a finite-element approach based on accurate three-dimensional model trees derived from terrestrial laser scanning data. We show that (1) residual variation, the variation not explained by the cantilever beam approximation, in fundamental frequencies of broadleaf trees is driven by their architecture; (2) slender trees behave like a simple pendulum, with a single natural frequency dominating their motion, which makes them vulnerable to wind damage and (3) the presence of leaves decreases both the fundamental frequency and the damping ratio. These findings demonstrate the value of new three-dimensional measurements for understanding wind impacts on trees and suggest new directions for improving our understanding of tree dynamics from conifer plantations to natural forests. KW - finite-element analysis KW - fundamental frequency KW - natural frequencies KW - terrestrial laser scanning KW - tree architecture KW - wind damage U2 - 10.1098/rsif.2019.0116 DO - 10.1098/rsif.2019.0116 M3 - Article VL - 16 JO - Journal of the Royal Society. Interface JF - Journal of the Royal Society. Interface SN - 1742-5689 IS - 155 ER - TY - JOUR T1 - An implementation of a semantic, web-based virtual machine laboratory prototyping environment AU - Salonen, Jaakko AU - Nykänen, Ossi AU - Ranta, Pekka AU - Nurmi, Juha AU - Helminen, Matti AU - Rokala, Markus AU - Palonen, Tuija AU - Alarotu, Vänni AU - Koskinen, Kari AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=0.5

Contribution: organisation=iha,FACT2=0.5 PY - 2011 Y1 - 2011 N2 - Creation of virtual machine laboratories – simulated planning and learning environments demonstrating function and structure of working machines – often involve a lot of manual labor. A notable source of the labor is the programming required due to changes in structural and functional models of a system. As a result, rapid prototyping of a virtual machine laboratory becomes difficult, if not impossible. We argue that by using a combination of semantic modeling and prototyping with a web-based system, more rapid development of virtual machine laboratories can be achieved. In this paper, we present the design and implementation of a semantic, web-based virtual machine laboratory prototyping environment. Application of the environment to a case example is also described and discussed. AB - Creation of virtual machine laboratories – simulated planning and learning environments demonstrating function and structure of working machines – often involve a lot of manual labor. A notable source of the labor is the programming required due to changes in structural and functional models of a system. As a result, rapid prototyping of a virtual machine laboratory becomes difficult, if not impossible. We argue that by using a combination of semantic modeling and prototyping with a web-based system, more rapid development of virtual machine laboratories can be achieved. In this paper, we present the design and implementation of a semantic, web-based virtual machine laboratory prototyping environment. Application of the environment to a case example is also described and discussed. U2 - 10.1007/978-3-642-25093-4_15 DO - 10.1007/978-3-642-25093-4_15 M3 - Article VL - 7032 SP - 221 EP - 236 JO - Lecture Notes in Computer Science JF - Lecture Notes in Computer Science SN - 0302-9743 ER - TY - JOUR T1 - A note on compactness in a fuzzy metric space AU - Kaleva, Osmo AU - Kauhanen, Janne N1 - In Press, Corrected Proof.Accepted 29 May 2013.

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-10-29 PY - 2013 Y1 - 2013 U2 - 10.1016/j.fss.2013.05.014 DO - 10.1016/j.fss.2013.05.014 M3 - Article SP - 135 EP - 139 JO - Fuzzy Sets and Systems JF - Fuzzy Sets and Systems SN - 0165-0114 M1 - 238 ER - TY - JOUR T1 - Another paraconsistent algebraic semantics for Lukasiewicz-Pavelka logic AU - Rodriguez, J. Tinguaro AU - Turunen, Esko AU - Ruan, Da AU - Montero, Javier N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-09-30

Publisher name: Elsevier BV PY - 2014 Y1 - 2014 U2 - 10.1016/j.fss.2013.06.011 DO - 10.1016/j.fss.2013.06.011 M3 - Article VL - 242 SP - 132 EP - 147 JO - Fuzzy Sets and Systems JF - Fuzzy Sets and Systems SN - 0165-0114 ER - TY - JOUR T1 - Antichain Cutsets of Strongly Connected Posets AU - Foldes, Stephan AU - Woodroofe, Russ N1 - Online first.Poistettu Portfolio13:sta tupla r=2900.

Contribution: organisation=mat,FACT1=1

Publisher name: Springer Netherlands PY - 2013 Y1 - 2013 U2 - 10.1007/s11083-012-9248-2 DO - 10.1007/s11083-012-9248-2 M3 - Article VL - 30 SP - 351 EP - 361 JO - Order: A Journal on the Theory of Ordered Sets and Its Applications JF - Order: A Journal on the Theory of Ordered Sets and Its Applications SN - 0167-8094 IS - 2 ER - TY - JOUR T1 - Aperture size effects on backscatter intensity measurements in Earth and space remote sensing AU - Kaasalainen, M. AU - Kaasalainen, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2008 Y1 - 2008 U2 - 10.1364/JOSAA.25.001142 DO - 10.1364/JOSAA.25.001142 M3 - Article VL - 25 SP - 1142 EP - 1146 JO - Journal of the Optical Society of America A: Optics Image Science and Vision JF - Journal of the Optical Society of America A: Optics Image Science and Vision SN - 1084-7529 IS - 5 ER - TY - JOUR T1 - A portrait of the nucleus of comet 67P AU - Lamy, P.L. AU - Toth, I. AU - Davidsson, B.J.R. AU - Groussin, O. AU - Gutierrez, P. AU - Jorda, L. AU - Kaasalainen, M. AU - Lowry, S.C. N1 - Contribution: organisation=mat,FACT1=1 PY - 2006 Y1 - 2006 U2 - 10.1007/s11214-007-9146-x DO - 10.1007/s11214-007-9146-x M3 - Article VL - 128 SP - 23 EP - 66 JO - Space Science Reviews JF - Space Science Reviews SN - 0038-6308 IS - 1-4 ER - TY - JOUR T1 - Apparent wind load effects on the tether of a kite power generator AU - Argatov, Ivan AU - Rautakorpi, Pauli AU - Silvennoinen, Risto N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1016/j.jweia.2011.07.010 DO - 10.1016/j.jweia.2011.07.010 M3 - Article VL - 99 SP - 1079 EP - 1088 JO - Journal of Wind Engineering and Industrial Aerodynamics JF - Journal of Wind Engineering and Industrial Aerodynamics SN - 0167-6105 IS - 10 ER - TY - JOUR T1 - Applications of Spatially Localized Active-Intensity Vectors for Sound-Field visualization AU - McCormack, Leo AU - Delikaris-Manias, Symeon AU - Politis, Archontis AU - Pavlidi, Despoina AU - Farina, Angelo AU - Pinardi, Daniel AU - Pulkki, Ville PY - 2019/11/22 Y1 - 2019/11/22 N2 - This article details and evaluates three alternative approaches to sound-field visualization, which all employ the use of spatially-localized active-intensity (SLAI) vectors. SLAI vectors are particularly interesting as they allow direction-of-arrival (DoA) estimates to be extracted in multiple spatially-localized sectors, such that sound sources and/or noise present in one sector has reduced influence on the DoA estimate made in the other sectors. These DoA estimates may then be used to visualize the sound-field by either: i) directly depicting the estimates as icons, with their relative size dictated by the corresponding energy of each sector; ii) generating traditional activity-maps via histogram analysis of the DoA estimates; or iii) by using the DoA estimates to re-assign energy and subsequently sharpen traditional beamformer-based activity-maps. Since SLAI-based DoA estimates are continuous, these approaches are inherently computationally efficient, as they forgo the need for dense scanning grids to attain high-resolution imaging. AB - This article details and evaluates three alternative approaches to sound-field visualization, which all employ the use of spatially-localized active-intensity (SLAI) vectors. SLAI vectors are particularly interesting as they allow direction-of-arrival (DoA) estimates to be extracted in multiple spatially-localized sectors, such that sound sources and/or noise present in one sector has reduced influence on the DoA estimate made in the other sectors. These DoA estimates may then be used to visualize the sound-field by either: i) directly depicting the estimates as icons, with their relative size dictated by the corresponding energy of each sector; ii) generating traditional activity-maps via histogram analysis of the DoA estimates; or iii) by using the DoA estimates to re-assign energy and subsequently sharpen traditional beamformer-based activity-maps. Since SLAI-based DoA estimates are continuous, these approaches are inherently computationally efficient, as they forgo the need for dense scanning grids to attain high-resolution imaging. U2 - 10.17743/jaes.2019.0041 DO - 10.17743/jaes.2019.0041 M3 - Article VL - 67 SP - 840 EP - 854 JO - Journal of the Audio Engineering Society JF - Journal of the Audio Engineering Society SN - 1549-4950 IS - 11 ER - TY - JOUR T1 - Approximate Controllability for Navier–Stokes Equations in 3D Rectangles Under Lions Boundary Conditions AU - Phan, Duy AU - Rodrigues, Sérgio S. PY - 2019/7 Y1 - 2019/7 N2 - The 3D Navier–Stokes system, under Lions boundary conditions, is proven to be approximately controllable provided a suitable saturating set does exist. An explicit saturating set for 3D rectangles is given. AB - The 3D Navier–Stokes system, under Lions boundary conditions, is proven to be approximately controllable provided a suitable saturating set does exist. An explicit saturating set for 3D rectangles is given. KW - Approximate controllability KW - Navier–Stokes equations KW - Saturating set U2 - 10.1007/s10883-018-9412-0 DO - 10.1007/s10883-018-9412-0 M3 - Article VL - 25 SP - 351 EP - 376 JO - Journal of Dynamical and Control Systems JF - Journal of Dynamical and Control Systems SN - 1079-2724 IS - 3 ER - TY - JOUR T1 - Approximative solutions to the bicriterion Vechile Routing Problem with Time Windows AU - Muller, Juliane N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1016/j.ejor.2009.04.029 DO - 10.1016/j.ejor.2009.04.029 M3 - Article VL - 202 SP - 223 EP - 231 JO - European Journal of Operational Research JF - European Journal of Operational Research SN - 0377-2217 IS - 1 ER - TY - JOUR T1 - A realistic, accurate and fast source modeling approach for the EEG forward problem AU - Miinalainen, Tuuli AU - Rezaei, Atena AU - Us, Defne AU - Nüßing, Andreas AU - Engwer, Christian AU - Wolters, Carsten H. AU - Pursiainen, Sampsa PY - 2019 Y1 - 2019 N2 - The aim of this paper is to advance electroencephalography (EEG) source analysis using finite element method (FEM) head volume conductor models that go beyond the standard three compartment (skin, skull, brain) approach and take brain tissue inhomogeneity (gray and white matter and cerebrospinal fluid) into account. The new approach should enable accurate EEG forward modeling in the thin human cortical structures and, more specifically, in the especially thin cortices in children brain research or in pathological applications. The source model should thus be focal enough to be usable in the thin cortices, but should on the other side be more realistic than the current standard mathematical point dipole. Furthermore, it should be numerically accurate and computationally fast. We propose to achieve the best balance between these demands with a current preserving (divergence conforming) dipolar source model. We develop and investigate a varying number of current preserving source basis elements n (n=1,…,n=5). For validation, we conducted numerical experiments within a multi-layered spherical domain, where an analytical solution exists. We show that the accuracy increases along with the number of basis elements, while focality decreases. The results suggest that the best balance between accuracy and focality in thin cortices is achieved with n=4 (or in extreme cases even n=3) basis functions, while in thicker cortices n=5 is recommended to obtain the highest accuracy. We also compare the current preserving approach to two further FEM source modeling techniques, namely partial integration and St. Venant, and show that the best current preserving source model outperforms the competing methods with regard to overall balance. For all tested approaches, FEM transfer matrices enable high computational speed. We implemented the new EEG forward modeling approaches into the open source duneuro library for forward modeling in bioelectromagnetism to enable its broader use by the brain research community. This library is build upon the DUNE framework for parallel finite elements simulations and integrates with high-level toolboxes like FieldTrip. Additionally, an inversion test has been implemented using the realistic head model to demonstrate and compare the differences between the aforementioned source models. AB - The aim of this paper is to advance electroencephalography (EEG) source analysis using finite element method (FEM) head volume conductor models that go beyond the standard three compartment (skin, skull, brain) approach and take brain tissue inhomogeneity (gray and white matter and cerebrospinal fluid) into account. The new approach should enable accurate EEG forward modeling in the thin human cortical structures and, more specifically, in the especially thin cortices in children brain research or in pathological applications. The source model should thus be focal enough to be usable in the thin cortices, but should on the other side be more realistic than the current standard mathematical point dipole. Furthermore, it should be numerically accurate and computationally fast. We propose to achieve the best balance between these demands with a current preserving (divergence conforming) dipolar source model. We develop and investigate a varying number of current preserving source basis elements n (n=1,…,n=5). For validation, we conducted numerical experiments within a multi-layered spherical domain, where an analytical solution exists. We show that the accuracy increases along with the number of basis elements, while focality decreases. The results suggest that the best balance between accuracy and focality in thin cortices is achieved with n=4 (or in extreme cases even n=3) basis functions, while in thicker cortices n=5 is recommended to obtain the highest accuracy. We also compare the current preserving approach to two further FEM source modeling techniques, namely partial integration and St. Venant, and show that the best current preserving source model outperforms the competing methods with regard to overall balance. For all tested approaches, FEM transfer matrices enable high computational speed. We implemented the new EEG forward modeling approaches into the open source duneuro library for forward modeling in bioelectromagnetism to enable its broader use by the brain research community. This library is build upon the DUNE framework for parallel finite elements simulations and integrates with high-level toolboxes like FieldTrip. Additionally, an inversion test has been implemented using the realistic head model to demonstrate and compare the differences between the aforementioned source models. KW - Divergence conforming vector fields KW - DUNE toolbox KW - Electroencephalography (EEG) KW - Finite element method (FEM) KW - Focal sources U2 - 10.1016/j.neuroimage.2018.08.054 DO - 10.1016/j.neuroimage.2018.08.054 M3 - Article VL - 184 SP - 56 EP - 67 JO - NeuroImage JF - NeuroImage SN - 1053-8119 IS - 1 ER - TY - JOUR T1 - A Self-Tuning Robust Regulator for Infinite-Dimensional Systems AU - Hämäläinen, Timo AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Electrical and Electronics Engineers IEEE PY - 2011 Y1 - 2011 U2 - 10.1109/TAC.2011.2129310 DO - 10.1109/TAC.2011.2129310 M3 - Article VL - 56 SP - 2116 EP - 2127 JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 IS - 9 ER - TY - JOUR T1 - A Simple Character String Proof of the "True but Unprovable'' Version of Gödel's First Incompleteness Theorem AU - Valmari, Antti N1 - Paper presented also in the Proceedings of the 14th International Conference Automata and Formal Languages (AFL 2014).

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-11-17

Publisher name: Open Publishing Association PY - 2014 Y1 - 2014 U2 - 10.4204/EPTCS.151.25 DO - 10.4204/EPTCS.151.25 M3 - Article VL - 151 SP - 355 EP - 369 JO - Electronic Proceedings in Theoretical Computer Science JF - Electronic Proceedings in Theoretical Computer Science SN - 2075-2180 M1 - 25 ER - TY - JOUR T1 - Assessing coupling dynamics from an ensemble of time series AU - Gómez-Herrero, Germán AU - Wu, Wei AU - Rutanen, Kalle AU - Soriano, Miguel C. AU - Pipa, Gordon AU - Vicente, Raul N1 - EXT="Gómez-Herrero,Germán" PY - 2015 Y1 - 2015 N2 - Finding interdependency relations between time series provides valuable knowledge about the processes that generated the signals. Information theory sets a natural framework for important classes of statistical dependencies. However, a reliable estimation from information-theoretic functionals is hampered when the dependency to be assessed is brief or evolves in time. Here, we show that these limitations can be partly alleviated when we have access to an ensemble of independent repetitions of the time series. In particular, we gear a data-efficient estimator of probability densities to make use of the full structure of trial-based measures. By doing so, we can obtain time-resolved estimates for a family of entropy combinations (including mutual information, transfer entropy and their conditional counterparts), which are more accurate than the simple average of individual estimates over trials. We show with simulated and real data generated by coupled electronic circuits that the proposed approach allows one to recover the time-resolved dynamics of the coupling between different subsystems. AB - Finding interdependency relations between time series provides valuable knowledge about the processes that generated the signals. Information theory sets a natural framework for important classes of statistical dependencies. However, a reliable estimation from information-theoretic functionals is hampered when the dependency to be assessed is brief or evolves in time. Here, we show that these limitations can be partly alleviated when we have access to an ensemble of independent repetitions of the time series. In particular, we gear a data-efficient estimator of probability densities to make use of the full structure of trial-based measures. By doing so, we can obtain time-resolved estimates for a family of entropy combinations (including mutual information, transfer entropy and their conditional counterparts), which are more accurate than the simple average of individual estimates over trials. We show with simulated and real data generated by coupled electronic circuits that the proposed approach allows one to recover the time-resolved dynamics of the coupling between different subsystems. KW - Ensemble KW - Entropy KW - Estimator KW - Time series KW - Transfer entropy KW - Trial UR - http://www.scopus.com/inward/record.url?scp=84930319366&partnerID=8YFLogxK U2 - 10.3390/e17041958 DO - 10.3390/e17041958 M3 - Article VL - 17 SP - 1958 EP - 1970 JO - Entropy JF - Entropy SN - 1099-4300 IS - 4 ER - TY - JOUR T1 - Asteroid 2867 Steins - II. Multi-telescope visible observations, shape reconstruction, and rotational state AU - Lamy, P.L. AU - Kaasalainen, M. AU - Lowry, S. AU - Weissman, P. AU - Barucci, M.A. AU - Carvano, J. AU - Choi, Y.-J. AU - Colas, F. AU - Faury, G. AU - Fornasier, S. AU - Groussin, O. AU - Hicks, M.D. AU - Jorda, L. AU - Kryszczynska, A. AU - Larson, S. AU - Toth, I. AU - Warner, B. N1 - Contribution: organisation=mat,FACT1=1

Publisher name: EDP Sciences PY - 2008 Y1 - 2008 U2 - 10.1051/0004-6361:20078995 DO - 10.1051/0004-6361:20078995 M3 - Article VL - 487 SP - 1179 EP - 1185 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - 3 ER - TY - JOUR T1 - Asteroid (2867) Steins: Shape, topography and global physical properties from OSIRIS observations AU - Jorda, L. AU - Lamy, P. AU - Gaskell, R. AU - Kaasalainen, Mikko AU - Groussin, O. AU - Besse, S. AU - Faury, G. N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Academic Press PY - 2012 Y1 - 2012 U2 - 10.1016/j.icarus.2012.07.035 DO - 10.1016/j.icarus.2012.07.035 M3 - Article VL - 221 SP - 1089 EP - 1100 JO - Icarus JF - Icarus SN - 0019-1035 IS - 2 ER - TY - JOUR T1 - Asteroid models from combined sparse and dense photometric data AU - Durech, J. AU - Kaasalainen, M. AU - Warner, B.D. AU - Fauerbach, M. AU - Mark, S.A. AU - Fauvaud, S. AU - Fauvaud, M. AU - Vugnon, J.-M. AU - Pilcher, F. AU - Bernasconi, L. AU - Behrend, R. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 U2 - 10.1051/0004-6361:200810393 DO - 10.1051/0004-6361:200810393 M3 - Article VL - 493 SP - 291 EP - 297 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - 1 ER - TY - JOUR T1 - Asteroid models from the Pan-STARRS photometry AU - Durech, J. AU - Grav, T. AU - Jedicke, R. AU - Kaasalainen, M. AU - Denneau, L. N1 - Contribution: organisation=mat,FACT1=1 PY - 2005 Y1 - 2005 U2 - 10.1007/s11038-006-9084-8 DO - 10.1007/s11038-006-9084-8 M3 - Article VL - 97 SP - 179 EP - 187 JO - Earth, Moon, and Planets JF - Earth, Moon, and Planets IS - 3-4 ER - TY - JOUR T1 - A study of crown development mechanisms using a shoot-based tree model and segmented terrestrial laser scanning data AU - Sievänen, Risto AU - Raumonen, Pasi AU - Perttunen, Jari AU - Nikinmaa, Eero AU - Kaitaniemi, Pekka PY - 2018/8/27 Y1 - 2018/8/27 N2 - Background and Aims Functional-structural plant models (FSPMs) allow simulation of tree crown development as the sum of modular (e.g. shoot-level) responses triggered by the local environmental conditions. The actual process of space filling by the crowns can be studied. Although the FSPM simulations are at organ scale, the data for their validation have usually been at more aggregated levels (whole-crown or whole-tree). Measurements made by terrestrial laser scanning (TLS) that have been segmented into elementary units (internodes) offer a phenotyping tool to validate the FSPM predictions at levels comparable with their detail. We demonstrate the testing of different formulations of crown development of Scots pine trees in the LIGNUM model using segmented TLS data. Methods We made TLS measurements from four sample trees growing in a forest on a relatively poor soil from sapling size to mature stage. The TLS data were segmented into internodes. The segmentation also produced information on whether needles were present in the internode. We applied different formulations of crown development (flushing of buds and length of growth of new internodes) in LIGNUM. We optimized the parameter values of each formulation using genetic algorithms to observe the best fit of LIGNUM simulations to the measured trees. The fitness function in the estimation combined both tree-level characteristics (e.g. tree height and crown length) and measures of crown shape (e.g. spatial distribution of needle area). Key Results Comparison of different formulations against the data indicates that the Extended Borchert-Honda model for shoot elongation works best within LIGNUM. Control of growth by local density in the crown was important for all shoot elongation formulations. Modifying the number of lateral buds as a function of local density in the crown was the best way to accomplish density control. Conclusions It was demonstrated how segmented TLS data can be used in the context of a shoot-based model to select model components. AB - Background and Aims Functional-structural plant models (FSPMs) allow simulation of tree crown development as the sum of modular (e.g. shoot-level) responses triggered by the local environmental conditions. The actual process of space filling by the crowns can be studied. Although the FSPM simulations are at organ scale, the data for their validation have usually been at more aggregated levels (whole-crown or whole-tree). Measurements made by terrestrial laser scanning (TLS) that have been segmented into elementary units (internodes) offer a phenotyping tool to validate the FSPM predictions at levels comparable with their detail. We demonstrate the testing of different formulations of crown development of Scots pine trees in the LIGNUM model using segmented TLS data. Methods We made TLS measurements from four sample trees growing in a forest on a relatively poor soil from sapling size to mature stage. The TLS data were segmented into internodes. The segmentation also produced information on whether needles were present in the internode. We applied different formulations of crown development (flushing of buds and length of growth of new internodes) in LIGNUM. We optimized the parameter values of each formulation using genetic algorithms to observe the best fit of LIGNUM simulations to the measured trees. The fitness function in the estimation combined both tree-level characteristics (e.g. tree height and crown length) and measures of crown shape (e.g. spatial distribution of needle area). Key Results Comparison of different formulations against the data indicates that the Extended Borchert-Honda model for shoot elongation works best within LIGNUM. Control of growth by local density in the crown was important for all shoot elongation formulations. Modifying the number of lateral buds as a function of local density in the crown was the best way to accomplish density control. Conclusions It was demonstrated how segmented TLS data can be used in the context of a shoot-based model to select model components. KW - forest stand KW - Functional-structural model KW - Scots pine KW - terrestrial laser scanning U2 - 10.1093/aob/mcy082 DO - 10.1093/aob/mcy082 M3 - Article VL - 122 SP - 423 EP - 434 JO - Annals of Botany JF - Annals of Botany SN - 0305-7364 IS - 3 ER - TY - JOUR T1 - Asymptotic behaviour in the robot rendezvous problem AU - Paunonen, Lassi AU - Seifert, David PY - 2017/5/1 Y1 - 2017/5/1 N2 - This paper presents a natural extension of the results obtained by Feintuch and Francis in (2012a,b) concerning the so-called robot rendezvous problem. In particular, we revisit a known necessary and sufficient condition for convergence of the solution in terms of Cesàro convergence of the translates Skx0, k≥0, of the sequence x0 of initial positions under the right-shift operator S, thus shedding new light on questions left open in Feintuch and Francis (2012a,b). We then present a new proof showing that a certain stronger ergodic condition on x0 ensures that the corresponding solution converges to its limit at the optimal rate O(t−1/2) as t→∞. After considering a natural two-sided variant of the robot rendezvous problem already studied in Feintuch and Francis (2012a) and in particular proving a new quantified result in this case, we conclude by relating the robot rendezvous problem to a more realistic model of vehicle platoons. AB - This paper presents a natural extension of the results obtained by Feintuch and Francis in (2012a,b) concerning the so-called robot rendezvous problem. In particular, we revisit a known necessary and sufficient condition for convergence of the solution in terms of Cesàro convergence of the translates Skx0, k≥0, of the sequence x0 of initial positions under the right-shift operator S, thus shedding new light on questions left open in Feintuch and Francis (2012a,b). We then present a new proof showing that a certain stronger ergodic condition on x0 ensures that the corresponding solution converges to its limit at the optimal rate O(t−1/2) as t→∞. After considering a natural two-sided variant of the robot rendezvous problem already studied in Feintuch and Francis (2012a) and in particular proving a new quantified result in this case, we conclude by relating the robot rendezvous problem to a more realistic model of vehicle platoons. KW - Autonomous systems KW - Mobile robots KW - Rates of convergence KW - Stability U2 - 10.1016/j.automatica.2017.02.015 DO - 10.1016/j.automatica.2017.02.015 M3 - Article VL - 79 SP - 127 EP - 130 JO - Automatica JF - Automatica SN - 0005-1098 ER - TY - JOUR T1 - Asymptotic Behaviour of Coupled Systems in Discrete and Continuous Time AU - Paunonen, Lassi AU - Seifert, David PY - 2018/6 Y1 - 2018/6 N2 - This paper investigates the asymptotic behaviour of solutions to certain infinite systems of coupled recurrence relations. In particular, we obtain a characterisation of those initial values which lead to a convergent solution, and for initial values satisfying a slightly stronger condition we obtain an optimal estimate on the rate of convergence. By establishing a connection with a related problem in continuous time, we are able to use this optimal estimate to improve the rate of convergence in the continuous setting obtained by the authors in a previous paper. We illustrate the power of the general approach by using it to study several concrete examples, both in continuous and in discrete time. AB - This paper investigates the asymptotic behaviour of solutions to certain infinite systems of coupled recurrence relations. In particular, we obtain a characterisation of those initial values which lead to a convergent solution, and for initial values satisfying a slightly stronger condition we obtain an optimal estimate on the rate of convergence. By establishing a connection with a related problem in continuous time, we are able to use this optimal estimate to improve the rate of convergence in the continuous setting obtained by the authors in a previous paper. We illustrate the power of the general approach by using it to study several concrete examples, both in continuous and in discrete time. KW - $C_0$-semigroups KW - Asymptotic behaviour KW - Power-boundeness KW - Rates of convergence KW - Recurrence relations KW - Spectral theory KW - System U2 - 10.1007/s10884-016-9547-1 DO - 10.1007/s10884-016-9547-1 M3 - Article VL - 30 SP - 433 EP - 445 JO - JOURNAL OF DYNAMICS AND DIFFERENTIAL EQUATIONS JF - JOURNAL OF DYNAMICS AND DIFFERENTIAL EQUATIONS SN - 1040-7294 IS - 2 ER - TY - JOUR T1 - Asymptotic modeling of unconstrained control of a tethered power kite moving along a given closed-loop spherical trajectory AU - Silvennoinen, Risto AU - Argatov, Ivan N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Springer Netherlands PY - 2012 Y1 - 2012 U2 - 10.1007/s10665-011-9475-3 DO - 10.1007/s10665-011-9475-3 M3 - Article VL - 72 SP - 187 EP - 203 JO - Journal of Engineering Mathematics JF - Journal of Engineering Mathematics SN - 0022-0833 IS - 1 ER - TY - JOUR T1 - Asymptotics for infinite systems of differential equations AU - Paunonen, Lassi AU - Seifert, David PY - 2017 Y1 - 2017 N2 - This paper investigates the asymptotic behavior of solutions to certain infinite systems of ordinary differential equations. In particular, we use results from ergodic theory and the asymptotic theory of C0-semigroups to obtain a characterization, in terms of convergence of certain Cesàro averages, of those initial values which lead to convergent solutions. Moreover, we obtain estimates on the rate of convergence for solutions whose initial values satisfy a stronger ergodic condition. These results rely on a detailed spectral analysis of the operator describing the system, which is made possible by certain structural assumptions on the operator. The resulting class of systems is sufficiently broad to cover a number of important applications including, in particular, both the so-called robot rendezvous problem and an important class of platoon systems arising in control theory. Our method leads to new results in both cases. AB - This paper investigates the asymptotic behavior of solutions to certain infinite systems of ordinary differential equations. In particular, we use results from ergodic theory and the asymptotic theory of C0-semigroups to obtain a characterization, in terms of convergence of certain Cesàro averages, of those initial values which lead to convergent solutions. Moreover, we obtain estimates on the rate of convergence for solutions whose initial values satisfy a stronger ergodic condition. These results rely on a detailed spectral analysis of the operator describing the system, which is made possible by certain structural assumptions on the operator. The resulting class of systems is sufficiently broad to cover a number of important applications including, in particular, both the so-called robot rendezvous problem and an important class of platoon systems arising in control theory. Our method leads to new results in both cases. KW - Asymptotic behavior KW - C0-semigroup KW - Ergodic theory KW - Ordinary differential equations KW - Rates of convergence KW - Spectrum KW - System U2 - 10.1137/15M1051993 DO - 10.1137/15M1051993 M3 - Article VL - 55 SP - 1153 EP - 1178 JO - SIAM Journal on Control and Optimization JF - SIAM Journal on Control and Optimization SN - 0363-0129 IS - 2 ER - TY - JOUR T1 - Asymptotics for periodic systems AU - Paunonen, Lassi AU - Seifert, David PY - 2019/5 Y1 - 2019/5 N2 - This paper investigates the asymptotic behaviour of solutions of periodic evolution equations. Starting with a general result concerning the quantified asymptotic behaviour of periodic evolution families we go on to consider a special class of dissipative systems arising naturally in applications. For this class of systems we analyse in detail the spectral properties of the associated monodromy operator, showing in particular that it is a so-called Ritt operator under a natural ‘resonance’ condition. This allows us to deduce from our general result a precise description of the asymptotic behaviour of the corresponding solutions. In particular, we present conditions for rational rates of convergence to periodic solutions in the case where the convergence fails to be uniformly exponential. We illustrate our general results by applying them to concrete problems including the one-dimensional wave equation with periodic damping. AB - This paper investigates the asymptotic behaviour of solutions of periodic evolution equations. Starting with a general result concerning the quantified asymptotic behaviour of periodic evolution families we go on to consider a special class of dissipative systems arising naturally in applications. For this class of systems we analyse in detail the spectral properties of the associated monodromy operator, showing in particular that it is a so-called Ritt operator under a natural ‘resonance’ condition. This allows us to deduce from our general result a precise description of the asymptotic behaviour of the corresponding solutions. In particular, we present conditions for rational rates of convergence to periodic solutions in the case where the convergence fails to be uniformly exponential. We illustrate our general results by applying them to concrete problems including the one-dimensional wave equation with periodic damping. KW - Damped wave equation KW - Evolution family KW - Non-autonomous system KW - Periodic KW - Rates of convergence KW - Ritt operator U2 - 10.1016/j.jde.2018.11.028 DO - 10.1016/j.jde.2018.11.028 M3 - Article VL - 266 SP - 7152 EP - 7172 JO - Journal of Differential Equations JF - Journal of Differential Equations SN - 0022-0396 IS - 11 ER - TY - JOUR T1 - A Time-Domain Multigrid Solver With Higher-Order Born Approximation for Full-Wave Radar Tomography of a Complex-Shaped Target AU - Sorsa, Liisa-Ida AU - Takala, Mika AU - Eyraud, Christelle AU - Pursiainen, Sampsa PY - 2020/1/6 Y1 - 2020/1/6 N2 - This article introduces and evaluates numerically a multigrid solver for non-linear tomographic radar imaging. Our goal is to enable the fast and robust inversion of sparse time-domain data with a mathematical full-wave approach utilizing a higher-order Born approximation (BA). Full-wave inversion is computationally expensive, hence techniques to speed up the numerical procedures are needed. To model the wave propagation effectively, we use the finite element time-domain (FETD) method, which is equipped with a multigrid scheme to enable the rapid evaluation of the higher-order BA. As a potential application, we consider the tomography of small solar system bodies (SSSBs) and asteroid interiors particular, the latter of which can contain internal details observable by radar, e.g., layers, voids and cracks. In the numerical experiments, we investigated monostatic, bistatic and multistatic measurement configurations. The results obtained suggest that, with a relevant noise level, the tomographic reconstruction quality can be improved by applying the higher-order BA in comparison to the first-order case, which we interpret as a linearization of the inverse problem. Our open multigrid-FETD solver for Matlab (The Mathworks Inc.) is available online. It applies Matlabs features for graphics computing unit acceleration to enhance computational performance. AB - This article introduces and evaluates numerically a multigrid solver for non-linear tomographic radar imaging. Our goal is to enable the fast and robust inversion of sparse time-domain data with a mathematical full-wave approach utilizing a higher-order Born approximation (BA). Full-wave inversion is computationally expensive, hence techniques to speed up the numerical procedures are needed. To model the wave propagation effectively, we use the finite element time-domain (FETD) method, which is equipped with a multigrid scheme to enable the rapid evaluation of the higher-order BA. As a potential application, we consider the tomography of small solar system bodies (SSSBs) and asteroid interiors particular, the latter of which can contain internal details observable by radar, e.g., layers, voids and cracks. In the numerical experiments, we investigated monostatic, bistatic and multistatic measurement configurations. The results obtained suggest that, with a relevant noise level, the tomographic reconstruction quality can be improved by applying the higher-order BA in comparison to the first-order case, which we interpret as a linearization of the inverse problem. Our open multigrid-FETD solver for Matlab (The Mathworks Inc.) is available online. It applies Matlabs features for graphics computing unit acceleration to enhance computational performance. U2 - 10.1109/TCI.2020.2964252 DO - 10.1109/TCI.2020.2964252 M3 - Article VL - 6 JO - IEEE Transactions on Computational Imaging JF - IEEE Transactions on Computational Imaging SN - 2333-9403 IS - December ER - TY - JOUR T1 - Automatic tree species recognition with quantitative structure models AU - Åkerblom, Markku AU - Raumonen, Pasi AU - Mäkipää, Raisa AU - Kaasalainen, Mikko PY - 2017/3/15 Y1 - 2017/3/15 N2 - We present three robust methods to accurately and automatically recognize tree species from terrestrial laser scanner data. The recognition is based on the use of quantitative structure tree models, which are hierarchical geometric primitive models accurately approximating the branching structure, geometry, and volume of the trees. Fifteen robust tree features are presented and tested with all different combinations for tree species classification. The classification methods presented are k-nearest neighbours, multinomial regression, and support vector machine based approaches. Three mainly single-species forest plots of Silver birch, Scots pine and Norway spruce, and two mixed-species forest plots located in Finland and a total number of trees over 1200 were used for demonstration. The results show that by using single-species forest plots for training and testing, it is possible to find a feature combination between 5 and 15 features, that results in an average classification accuracy above 93% for all the methods. For the preliminary mixed-species forest plot testing, accuracy was lower but the classification approach presented potential to generalize to more diverse cases. Moreover, the results show that the post-processing of terrestrial laser scanning data of multi-hectare forest, from tree extraction and modelling to species classification, can be done automatically. AB - We present three robust methods to accurately and automatically recognize tree species from terrestrial laser scanner data. The recognition is based on the use of quantitative structure tree models, which are hierarchical geometric primitive models accurately approximating the branching structure, geometry, and volume of the trees. Fifteen robust tree features are presented and tested with all different combinations for tree species classification. The classification methods presented are k-nearest neighbours, multinomial regression, and support vector machine based approaches. Three mainly single-species forest plots of Silver birch, Scots pine and Norway spruce, and two mixed-species forest plots located in Finland and a total number of trees over 1200 were used for demonstration. The results show that by using single-species forest plots for training and testing, it is possible to find a feature combination between 5 and 15 features, that results in an average classification accuracy above 93% for all the methods. For the preliminary mixed-species forest plot testing, accuracy was lower but the classification approach presented potential to generalize to more diverse cases. Moreover, the results show that the post-processing of terrestrial laser scanning data of multi-hectare forest, from tree extraction and modelling to species classification, can be done automatically. KW - Quantitative structure model KW - Terrestrial laser scanning KW - Tree reconstruction KW - Tree species recognition U2 - 10.1016/j.rse.2016.12.002 DO - 10.1016/j.rse.2016.12.002 M3 - Article VL - 191 SP - 1 EP - 12 JO - Remote Sensing of Environment JF - Remote Sensing of Environment SN - 0034-4257 ER - TY - JOUR T1 - Autonomous Prediction of GPS and GLONASS Satellite Orbits AU - Seppänen, Mari AU - Ala-Luhtala, Juha AU - Piche, Robert AU - Martikainen, Simo AU - Ali-Löytty, Simo N1 - ei ut-numeroa 29.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Navigation PY - 2012 Y1 - 2012 U2 - 10.1002/navi.10 DO - 10.1002/navi.10 M3 - Article VL - 59 SP - 119 EP - 134 JO - Navigation JF - Navigation SN - 0028-1522 IS - 2 ER - TY - JOUR T1 - Bayes Forest T2 - A data-intensive generator of morphological tree clones AU - Potapov, Ilya AU - Järvenpää, Marko AU - Åkerblom, Markku AU - Raumonen, Pasi AU - Kaasalainen, Mikko N1 - EXT="Järvenpää, Marko" PY - 2017 Y1 - 2017 N2 - Detailed and realistic tree form generators have numerous applications in ecology and forestry. For example, the varying morphology of trees contributes differently to formation of landscapes, natural habitats of species, and eco-physiological characteristics of the biosphere. Here, we present an algorithm for generating morphological tree "clones" based on the detailed reconstruction of the laser scanning data, statistical measure of similarity, and a plant growth model with simple stochastic rules. The algorithm is designed to produce tree forms, i.e., morphological clones, similar (and not identical) in respect to tree-level structure, but varying in fine-scale structural detail. Although we opted for certain choices in our algorithm, individual parts may vary depending on the application, making it a general adaptable pipeline. Namely, we showed that a specific multipurpose procedural stochastic growth model can be algorithmically adjusted to produce the morphological clones replicated from the target experimentally measured tree. For this, we developed a statistical measure of similarity (structural distance) between any given pair of trees, which allows for the comprehensive comparing of the tree morphologies by means of empirical distributions describing the geometrical and topological features of a tree. Finally, we developed a programmable interface to manipulate data required by the algorithm. Our algorithm can be used in a variety of applications for exploration of the morphological potential of the growth models (both theoretical and experimental), arising in all sectors of plant science research. AB - Detailed and realistic tree form generators have numerous applications in ecology and forestry. For example, the varying morphology of trees contributes differently to formation of landscapes, natural habitats of species, and eco-physiological characteristics of the biosphere. Here, we present an algorithm for generating morphological tree "clones" based on the detailed reconstruction of the laser scanning data, statistical measure of similarity, and a plant growth model with simple stochastic rules. The algorithm is designed to produce tree forms, i.e., morphological clones, similar (and not identical) in respect to tree-level structure, but varying in fine-scale structural detail. Although we opted for certain choices in our algorithm, individual parts may vary depending on the application, making it a general adaptable pipeline. Namely, we showed that a specific multipurpose procedural stochastic growth model can be algorithmically adjusted to produce the morphological clones replicated from the target experimentally measured tree. For this, we developed a statistical measure of similarity (structural distance) between any given pair of trees, which allows for the comprehensive comparing of the tree morphologies by means of empirical distributions describing the geometrical and topological features of a tree. Finally, we developed a programmable interface to manipulate data required by the algorithm. Our algorithm can be used in a variety of applications for exploration of the morphological potential of the growth models (both theoretical and experimental), arising in all sectors of plant science research. KW - Empirical distributions KW - Large scale data KW - Morphological clone KW - Quantitative structure tree model KW - Stochastic data driven model KW - Terrestrial laser scanning U2 - 10.1093/gigascience/gix079 DO - 10.1093/gigascience/gix079 M3 - Article VL - 6 JO - GigaScience JF - GigaScience SN - 2047-217X IS - 10 M1 - gix079 ER - TY - JOUR T1 - Bayesian analysis of GUHA hypotheses AU - Piche, Robert AU - Järvenpää, Marko AU - Turunen, Esko AU - Simunek, Milan N1 - Online first

Contribution: organisation=ase,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Portfolio EDEND: 2013-07-29

Publisher name: Springer PY - 2013 Y1 - 2013 U2 - 10.1007/s10844-013-0255-6 DO - 10.1007/s10844-013-0255-6 M3 - Article VL - 42 SP - 47 EP - 73 JO - Journal of Intelligent Information Systems JF - Journal of Intelligent Information Systems SN - 0925-9902 IS - 1 ER - TY - JOUR T1 - Binomial Gaussian mixture filter AU - Raitoharju, Matti AU - Ali-Löytty, Simo AU - Piché, Robert N1 - ORG=ase,0.75 ORG=mat,0.25 PY - 2015/12/2 Y1 - 2015/12/2 N2 - In this work, we present a novel method for approximating a normal distribution with a weighted sum of normal distributions. The approximation is used for splitting normally distributed components in a Gaussian mixture filter, such that components have smaller covariances and cause smaller linearization errors when nonlinear measurements are used for the state update. Our splitting method uses weights from the binomial distribution as component weights. The method preserves the mean and covariance of the original normal distribution, and in addition, the resulting probability density and cumulative distribution functions converge to the original normal distribution when the number of components is increased. Furthermore, an algorithm is presented to do the splitting such as to keep the linearization error below a given threshold with a minimum number of components. The accuracy of the estimate provided by the proposed method is evaluated in four simulated single-update cases and one time series tracking case. In these tests, it is found that the proposed method is more accurate than other Gaussian mixture filters found in the literature when the same number of components is used and that the proposed method is faster and more accurate than particle filters. AB - In this work, we present a novel method for approximating a normal distribution with a weighted sum of normal distributions. The approximation is used for splitting normally distributed components in a Gaussian mixture filter, such that components have smaller covariances and cause smaller linearization errors when nonlinear measurements are used for the state update. Our splitting method uses weights from the binomial distribution as component weights. The method preserves the mean and covariance of the original normal distribution, and in addition, the resulting probability density and cumulative distribution functions converge to the original normal distribution when the number of components is increased. Furthermore, an algorithm is presented to do the splitting such as to keep the linearization error below a given threshold with a minimum number of components. The accuracy of the estimate provided by the proposed method is evaluated in four simulated single-update cases and one time series tracking case. In these tests, it is found that the proposed method is more accurate than other Gaussian mixture filters found in the literature when the same number of components is used and that the proposed method is faster and more accurate than particle filters. KW - Estimation KW - Gaussian mixture filter KW - Nonlinear filtering UR - http://www.scopus.com/inward/record.url?scp=84934283964&partnerID=8YFLogxK U2 - 10.1186/s13634-015-0221-2 DO - 10.1186/s13634-015-0221-2 M3 - Article VL - 2015 JO - Eurasip Journal on Advances in Signal Processing JF - Eurasip Journal on Advances in Signal Processing SN - 1687-6172 IS - 1 M1 - 36 ER - TY - JOUR T1 - Bistatic full-wave radar tomography detects deep interior voids, cracks and boulders in a rubble-pile asteroid model. AU - Sorsa, Liisa-Ida AU - Takala, Mika AU - Bambach, Patrick AU - Deller, Jakob AU - Vilenius, Esa AU - Pursiainen, Sampsa PY - 2019/2/8 Y1 - 2019/2/8 N2 - In this paper, we investigate full-wave computed radar tomography (CRT) using a rubble-pile asteroid model in which a realistic shape (Itokawa) is coupled with a synthetic material composition and structure model. The aim is to show that sparse bistatic radar measurements can distinguish details inside a complex-structured rubble-pile asteroid. The results obtained suggest that distinct local permittivity distribution changes such as surface layers, voids, low-permittivity anomalies, high-permittivity boulders, and cracks can be detected with bistatic CRT, when the total noise level in the data is around −10 dB with respect to the signal amplitude. Moreover, the bistatic measurement setup improves the robustness of the inversion compared to the monostatic case. Reconstructing the smooth Gaussian background distribution was found to be difficult with the present approach, suggesting that complementary techniques, such as gravimetry, might be needed to improve the reliability of the inference in practice. AB - In this paper, we investigate full-wave computed radar tomography (CRT) using a rubble-pile asteroid model in which a realistic shape (Itokawa) is coupled with a synthetic material composition and structure model. The aim is to show that sparse bistatic radar measurements can distinguish details inside a complex-structured rubble-pile asteroid. The results obtained suggest that distinct local permittivity distribution changes such as surface layers, voids, low-permittivity anomalies, high-permittivity boulders, and cracks can be detected with bistatic CRT, when the total noise level in the data is around −10 dB with respect to the signal amplitude. Moreover, the bistatic measurement setup improves the robustness of the inversion compared to the monostatic case. Reconstructing the smooth Gaussian background distribution was found to be difficult with the present approach, suggesting that complementary techniques, such as gravimetry, might be needed to improve the reliability of the inference in practice. U2 - 10.3847/1538-4357/aafba2 DO - 10.3847/1538-4357/aafba2 M3 - Article VL - 872 JO - Astrophysical Journal JF - Astrophysical Journal SN - 0004-637X IS - 1 M1 - 44 ER - TY - JOUR T1 - Box Gaussian mixture filter AU - Ali-Löytty, Simo N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1109/TAC.2010.2051486 DO - 10.1109/TAC.2010.2051486 M3 - Article VL - 55 SP - 2165 EP - 2169 JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 IS - 9 ER - TY - JOUR T1 - Canonical methods of constructing invariant tori by phase-space sampling AU - Laakso, T. AU - Kaasalainen, M. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: Elsevier PY - 2013 Y1 - 2013 U2 - 10.1016/j.physd.2012.09.010 DO - 10.1016/j.physd.2012.09.010 M3 - Article VL - 243 SP - 14 EP - 19 JO - Physica D: Nonlinear Phenomena JF - Physica D: Nonlinear Phenomena SN - 0167-2789 IS - 1 ER - TY - JOUR T1 - Cauchy–Riemann Operators in Octonionic Analysis AU - Kauhanen, Janne AU - Orelma, Heikki PY - 2018 Y1 - 2018 N2 - In this paper we first recall the definition of the octonion algebra and its algebraic properties. We derive the so called e4-calculus and using it we obtain the list of generalized Cauchy–Riemann systems for octonionic monogenic functions. AB - In this paper we first recall the definition of the octonion algebra and its algebraic properties. We derive the so called e4-calculus and using it we obtain the list of generalized Cauchy–Riemann systems for octonionic monogenic functions. KW - Cauchy–Riemann operators KW - Dirac operators KW - Monogenic functions KW - Octonions U2 - 10.1007/s00006-018-0826-2 DO - 10.1007/s00006-018-0826-2 M3 - Article VL - 28 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 1 M1 - 1 ER - TY - JOUR T1 - Change Detection of Tree Biomass with Terrestrial Laser Scanning and Quantitative Structure Modelling AU - Kaasalainen, Sanna AU - Krooks, Anssi AU - Liski, Jari AU - Raumonen, Pasi AU - Kaartinen, Harri AU - Kaasalainen, Mikko AU - Puttonen, Eetu AU - Anttila, Kati AU - Mäkipää, Raisa N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-09-30

Publisher name: MDPI AG PY - 2014 Y1 - 2014 U2 - 10.3390/rs6053906 DO - 10.3390/rs6053906 M3 - Article VL - 6 SP - 3906 EP - 3922 JO - Remote Sensing JF - Remote Sensing SN - 2072-4292 IS - 5 ER - TY - JOUR T1 - Closed classes of functions, generalized constraints, and clusters AU - Lehtonen, Erkko N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1007/s00012-010-0071-6 DO - 10.1007/s00012-010-0071-6 M3 - Article VL - 63 SP - 203 EP - 234 JO - Algebra Universalis JF - Algebra Universalis SN - 0002-5240 IS - 2-3 ER - TY - JOUR T1 - Closing the gap between Earth-based and interplanetary mission observations T2 - Vesta seen by VLT/SPHERE AU - Fétick, R. J.L. AU - Jorda, L. AU - Vernazza, P. AU - Marsset, M. AU - Drouard, A. AU - Fusco, T. AU - Carry, B. AU - Marchis, F. AU - Hanuš, J. AU - Viikinkoski, M. AU - Birlan, M. AU - Bartczak, P. AU - Berthier, J. AU - Castillo-Rogez, J. AU - Cipriani, F. AU - Colas, F. AU - Dudziński, G. AU - Dumas, C. AU - Ferrais, M. AU - Jehin, E. AU - Kaasalainen, M. AU - Kryszczynska, A. AU - Lamy, P. AU - Le Coroller, H. AU - Marciniak, A. AU - Michalowski, T. AU - Michel, P. AU - Mugnier, L. M. AU - Neichel, B. AU - Pajuelo, M. AU - Podlewska-Gaca, E. AU - Santana-Ros, T. AU - Tanga, P. AU - Vachier, F. AU - Vigan, A. AU - Witasse, O. AU - Yang, B. PY - 2019/3/1 Y1 - 2019/3/1 N2 - Context. Over the past decades, several interplanetary missions have studied small bodies in situ, leading to major advances in our understanding of their geological and geophysical properties. These missions, however, have had a limited number of targets. Among them, the NASA Dawn mission has characterised in detail the topography and albedo variegation across the surface of asteroid (4) Vesta down to a spatial resolution of ~20 m pixel -1 scale. Aims. Here our aim was to determine how much topographic and albedo information can be retrieved from the ground with VLT/SPHERE in the case of Vesta, having a former space mission (Dawn) providing us with the ground truth that can be used as a benchmark. Methods. We observed Vesta with VLT/SPHERE/ZIMPOL as part of our ESO large programme (ID 199.C-0074) at six different epochs, and deconvolved the collected images with a parametric point spread function (PSF). We then compared our images with synthetic views of Vesta generated from the 3D shape model of the Dawn mission, on which we projected Vesta's albedo information. Results. We show that the deconvolution of the VLT/SPHERE images with a parametric PSF allows the retrieval of the main topographic and albedo features present across the surface of Vesta down to a spatial resolution of ~20-30 km. Contour extraction shows an accuracy of ~1 pixel (3.6 mas). The present study provides the very first quantitative estimate of the accuracy of ground-based adaptive-optics imaging observations of asteroid surfaces. Conclusions. In the case of Vesta, the upcoming generation of 30-40 m telescopes (ELT, TMT, GMT) should in principle be able to resolve all of the main features present across its surface, including the troughs and the north-south crater dichotomy, provided that they operate at the diffraction limit. AB - Context. Over the past decades, several interplanetary missions have studied small bodies in situ, leading to major advances in our understanding of their geological and geophysical properties. These missions, however, have had a limited number of targets. Among them, the NASA Dawn mission has characterised in detail the topography and albedo variegation across the surface of asteroid (4) Vesta down to a spatial resolution of ~20 m pixel -1 scale. Aims. Here our aim was to determine how much topographic and albedo information can be retrieved from the ground with VLT/SPHERE in the case of Vesta, having a former space mission (Dawn) providing us with the ground truth that can be used as a benchmark. Methods. We observed Vesta with VLT/SPHERE/ZIMPOL as part of our ESO large programme (ID 199.C-0074) at six different epochs, and deconvolved the collected images with a parametric point spread function (PSF). We then compared our images with synthetic views of Vesta generated from the 3D shape model of the Dawn mission, on which we projected Vesta's albedo information. Results. We show that the deconvolution of the VLT/SPHERE images with a parametric PSF allows the retrieval of the main topographic and albedo features present across the surface of Vesta down to a spatial resolution of ~20-30 km. Contour extraction shows an accuracy of ~1 pixel (3.6 mas). The present study provides the very first quantitative estimate of the accuracy of ground-based adaptive-optics imaging observations of asteroid surfaces. Conclusions. In the case of Vesta, the upcoming generation of 30-40 m telescopes (ELT, TMT, GMT) should in principle be able to resolve all of the main features present across its surface, including the troughs and the north-south crater dichotomy, provided that they operate at the diffraction limit. KW - Methods: observational KW - Minor planets, asteroids: individual: Vesta KW - Techniques: high angular resolution KW - Techniques: image processing U2 - 10.1051/0004-6361/201834749 DO - 10.1051/0004-6361/201834749 M3 - Article VL - 623 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A6 ER - TY - JOUR T1 - Clustering and achievement of engineering students based on their attitudes, orientations, motivations and intentions AU - Huikkola, M. AU - Silius, K. AU - Pohjolainen, S. N1 - Contribution: organisation=mat hyplab,FACT1=1 PY - 2008 Y1 - 2008 M3 - Article VL - 5 SP - 342 EP - 354 JO - WSEAS Transactions on Advances in Engineering Education JF - WSEAS Transactions on Advances in Engineering Education SN - 1790-1979 IS - 5 ER - TY - JOUR T1 - Column-partitioned matrices over rings without invertible transversal submatrices AU - Foldes, Stephane AU - Lehtonen, Erkko N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Article VL - 97 SP - 33 EP - 39 JO - Ars Combinatoria JF - Ars Combinatoria SN - 0381-7032 ER - TY - JOUR T1 - Combining asteroid models derived by lightcurve inversion with asteroidal occultation silhouettes AU - Durech, Josef AU - Kaasalainen, Mikko AU - Herald, David AU - Dunham, David AU - Timerson, Brad AU - Hanus, Josef AU - Frappa, Eric AU - Talbot, John AU - Hayamizu, Tsutomu AU - Warener, Brian D. AU - Pilcher, Frederick AU - Galad, Adrian N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1016/j.icarus.2011.03.016 DO - 10.1016/j.icarus.2011.03.016 M3 - Article VL - 214 SP - 652 EP - 670 JO - Icarus JF - Icarus SN - 0019-1035 IS - 2 ER - TY - JOUR T1 - Commutative bounded integral residuated orthomodular lattices are Boolean algebras AU - Tladlec, Josef AU - Turunen, Esko N1 - online first March 10, 2010

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1007/s00500-010-0572-4 DO - 10.1007/s00500-010-0572-4 M3 - Article VL - 15 SP - 635 EP - 636 JO - Soft Computing JF - Soft Computing SN - 1432-7643 IS - 4 ER - TY - JOUR T1 - Compact YORP formulation and stability analysis AU - Kaasalainen, M. AU - Nortunen, H. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: EDP Sciences PY - 2013 Y1 - 2013 U2 - 10.1051/0004-6361/201322221 DO - 10.1051/0004-6361/201322221 M3 - Article VL - 558 SP - 1 EP - 8 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A104 ER - TY - JOUR T1 - Comparison of wood volume estimates of young trees from terrestrial laser scan data AU - Kunz, Matthias AU - Hess, Carsten AU - Raumonen, Pasi AU - Bienert, Anne AU - Hackenberg, Jan AU - Maas, Hans Gerd AU - Härdtle, Werner AU - Fichtner, Andreas AU - Von Oheimb, Goddert PY - 2017/4/1 Y1 - 2017/4/1 N2 - Many analyses in ecology and forestry require wood volume estimates of trees. However, non-destructive measurements are not straightforward because trees are differing in their three-dimensional structures and shapes. In this paper we compared three methods (one voxel-based and two cylinder-based methods) for wood volume calculation of trees from point clouds obtained by terrestrial laser scanning. We analysed a total of 24 young trees, composed of four different species ranging between 1.79 m to 7.96 m in height, comparing the derived volume estimates from the point clouds with xylometric reference volumes for each tree. We found that both voxel-and cylinder-based approaches are able to compute wood volumes with an average accuracy above 90% when compared to reference volumes. The best results were achieved with the voxel-based method (r2 = 0.98). Cylinder-model based methods (r2 = 0.90 and 0.92 respectively) did perform slightly less well but offer valuable additional opportunities to analyse structural parameters for each tree. We found that the error of volume estimates from point clouds are strongly species-specific. Therefore, species-specific parameter sets for point-cloud based wood volume estimation methods are required for more robust estimates across a number of tree species. AB - Many analyses in ecology and forestry require wood volume estimates of trees. However, non-destructive measurements are not straightforward because trees are differing in their three-dimensional structures and shapes. In this paper we compared three methods (one voxel-based and two cylinder-based methods) for wood volume calculation of trees from point clouds obtained by terrestrial laser scanning. We analysed a total of 24 young trees, composed of four different species ranging between 1.79 m to 7.96 m in height, comparing the derived volume estimates from the point clouds with xylometric reference volumes for each tree. We found that both voxel-and cylinder-based approaches are able to compute wood volumes with an average accuracy above 90% when compared to reference volumes. The best results were achieved with the voxel-based method (r2 = 0.98). Cylinder-model based methods (r2 = 0.90 and 0.92 respectively) did perform slightly less well but offer valuable additional opportunities to analyse structural parameters for each tree. We found that the error of volume estimates from point clouds are strongly species-specific. Therefore, species-specific parameter sets for point-cloud based wood volume estimation methods are required for more robust estimates across a number of tree species. KW - Mixed forests KW - Quantitative structure models KW - Voxel-based KW - Xylometry U2 - 10.3832/ifor2151-010 DO - 10.3832/ifor2151-010 M3 - Article VL - 10 SP - 451 EP - 458 JO - iForest - Biogeosciences and Forestry JF - iForest - Biogeosciences and Forestry SN - 1971-7458 IS - 2 ER - TY - JOUR T1 - Comparison Study for Whitney (Raviart-Thomas) Type Source Models in Finite Element Method Based EEG Forward Modeling AU - Pursiainen, Sampsa AU - Bauer, Martin AU - Vorwerk, Johannes AU - Köstler, Harald AU - Wolters, Carsten H. PY - 2015/11 Y1 - 2015/11 N2 - This study concentrates on finite element method (FEM)based electroencephalography (EEG) forward simulation in which theelectric potential evoked by neural activity in the brain is to be calculatedat the surface of the head. The main advantage of the FEM is that it allowsrealistic modeling of tissue conductivity inhomogeneity. However, it is notstraightforward to apply the classical model of a dipolar source with theFEM, due to its strong singularity and the resulting irregularity. The focusof this study is on comparing different methods to cope with this problem.In particular, we evaluate the accuracy of Whitney (Raviart-Thomas) typedipole-like source currents compared to two reference dipole modelingmethods: the St. Venant and partial integration approach. Commonto all these methods is that they enable direct approximation of thepotential field utilizing linear basis functions. In the present context,Whitney elements are particularly interesting, as they provide a simplemeans to model a divergence-conforming primary current vector fieldsatisfying the square integrability condition. Our results show that aWhitney type source model can provide simulation accuracy comparableto the present reference methods. It can lead to superior accuracy underoptimized conditions with respect to both source location and orientationin a tetrahedral mesh. For random source orientations, the St. Venantapproach turns out to be the method of choice over the interpolatedversion of the Whitney model. The overall moderate differences obtainedsuggest that practical aspects, such as the focality, should be prioritizedwhen choosing a source model. AB - This study concentrates on finite element method (FEM)based electroencephalography (EEG) forward simulation in which theelectric potential evoked by neural activity in the brain is to be calculatedat the surface of the head. The main advantage of the FEM is that it allowsrealistic modeling of tissue conductivity inhomogeneity. However, it is notstraightforward to apply the classical model of a dipolar source with theFEM, due to its strong singularity and the resulting irregularity. The focusof this study is on comparing different methods to cope with this problem.In particular, we evaluate the accuracy of Whitney (Raviart-Thomas) typedipole-like source currents compared to two reference dipole modelingmethods: the St. Venant and partial integration approach. Commonto all these methods is that they enable direct approximation of thepotential field utilizing linear basis functions. In the present context,Whitney elements are particularly interesting, as they provide a simplemeans to model a divergence-conforming primary current vector fieldsatisfying the square integrability condition. Our results show that aWhitney type source model can provide simulation accuracy comparableto the present reference methods. It can lead to superior accuracy underoptimized conditions with respect to both source location and orientationin a tetrahedral mesh. For random source orientations, the St. Venantapproach turns out to be the method of choice over the interpolatedversion of the Whitney model. The overall moderate differences obtainedsuggest that practical aspects, such as the focality, should be prioritizedwhen choosing a source model. U2 - 10.1109/TBME.2015.2439282 DO - 10.1109/TBME.2015.2439282 M3 - Article VL - 62 SP - 2648 EP - 2656 JO - IEEE Transactions on Biomedical Engineering JF - IEEE Transactions on Biomedical Engineering SN - 0018-9294 IS - 11 ER - TY - JOUR T1 - Complex-domain Joint Broadband Hyperspectral Image Denoising AU - Katkovnik, Vladimir AU - Shevkunov, Igor AU - Claus, Daniel AU - Pedrini, Giancarlo AU - Egiazarian, Karen PY - 2019/5/1 Y1 - 2019/5/1 N2 - In this paper, we propose a novel complex domain denoising algorithm for hyperspectral data. The algorithm is based on the Complex Domain Block-Matching 3D (CDBM3D) filter and on similarity of hyperspectral data, which are usually slow varying for close values of wavelengths. Singular Value Decomposition (SVD) of the hyperspectral data is used in order to define an optimal small dimension data subspace. The CDBM3D is applied for 2D images of this subspace. The efficiency of the algorithm is demonstrated in simulation tests and for experimental data obtained by spectrally resolved digital holography of a transparent color object. It is proved that the proposed filtering algorithm retrieves amplitude and phase distributions even from very noisy data. AB - In this paper, we propose a novel complex domain denoising algorithm for hyperspectral data. The algorithm is based on the Complex Domain Block-Matching 3D (CDBM3D) filter and on similarity of hyperspectral data, which are usually slow varying for close values of wavelengths. Singular Value Decomposition (SVD) of the hyperspectral data is used in order to define an optimal small dimension data subspace. The CDBM3D is applied for 2D images of this subspace. The efficiency of the algorithm is demonstrated in simulation tests and for experimental data obtained by spectrally resolved digital holography of a transparent color object. It is proved that the proposed filtering algorithm retrieves amplitude and phase distributions even from very noisy data. M3 - Article VL - 233 SP - 33 EP - 39 JO - Sensors and Transducers JF - Sensors and Transducers SN - 1726-5479 IS - 5 ER - TY - JOUR T1 - Complexity of Rainbow Vertex Connectivity Problems for Restricted Graph Classes AU - Lauri, Juho PY - 2017/3/11 Y1 - 2017/3/11 N2 - A path in a vertex-colored graph G is vertex rainbow if all of its internal vertices have a distinct color. The graph G is said to be rainbow vertex connected if there is a vertex rainbow path between every pair of its vertices. Similarly, the graph G is strongly rainbow vertex connected if there is a shortest path which is vertex rainbow between every pair of its vertices. We consider the complexity of deciding if a given vertex-colored graph is rainbow or strongly rainbow vertex connected. We call these problems Rainbow Vertex Connectivity and Strong Rainbow Vertex Connectivity, respectively. We prove both problems remain NP-complete on very restricted graph classes including bipartite planar graphs of maximum degree 3, interval graphs, and kk-regular graphs for k≥3k≥3. We settle precisely the complexity of both problems from the viewpoint of two width parameters: pathwidth and tree-depth. More precisely, we show both problems remain NP-complete for bounded pathwidth graphs, while being fixed-parameter tractable parameterized by tree-depth. Moreover, we show both problems are solvable in polynomial time for block graphs, while Strong Rainbow Vertex Connectivity is tractable for cactus graphs and split graphs. AB - A path in a vertex-colored graph G is vertex rainbow if all of its internal vertices have a distinct color. The graph G is said to be rainbow vertex connected if there is a vertex rainbow path between every pair of its vertices. Similarly, the graph G is strongly rainbow vertex connected if there is a shortest path which is vertex rainbow between every pair of its vertices. We consider the complexity of deciding if a given vertex-colored graph is rainbow or strongly rainbow vertex connected. We call these problems Rainbow Vertex Connectivity and Strong Rainbow Vertex Connectivity, respectively. We prove both problems remain NP-complete on very restricted graph classes including bipartite planar graphs of maximum degree 3, interval graphs, and kk-regular graphs for k≥3k≥3. We settle precisely the complexity of both problems from the viewpoint of two width parameters: pathwidth and tree-depth. More precisely, we show both problems remain NP-complete for bounded pathwidth graphs, while being fixed-parameter tractable parameterized by tree-depth. Moreover, we show both problems are solvable in polynomial time for block graphs, while Strong Rainbow Vertex Connectivity is tractable for cactus graphs and split graphs. U2 - 10.1016/j.dam.2016.11.023 DO - 10.1016/j.dam.2016.11.023 M3 - Article VL - 219 SP - 132 EP - 146 JO - Discrete Applied Mathematics JF - Discrete Applied Mathematics SN - 0166-218X ER - TY - JOUR T1 - Computational study of noise in a large signal transduction network AU - Intosalmi, Jukka AU - Manninen, Tiina AU - Ruohonen, Keijo AU - Linne, Marja-Leena N1 - Contribution: organisation=sgn,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5 PY - 2011 Y1 - 2011 U2 - 10.1186/1471-2105-12-252 DO - 10.1186/1471-2105-12-252 M3 - Article VL - 12 SP - 1 EP - 8 JO - BMC Bioinformatics JF - BMC Bioinformatics SN - 1471-2105 M1 - 252 ER - TY - JOUR T1 - Compute mindlessly. Not! map consciously AU - Niemelä, P. AU - Mikkolainen, V. AU - Vuorinen, J. PY - 2018/11/1 Y1 - 2018/11/1 N2 - This paper utilizes concept mapping as a tool for conscious and deliberate knowledge building in mathematics and its extension to algorithms. Currently, alleged defects in mathematics education are obvious: instead of conceptual elaboration, everyday praxis relies on routine computations that are likely to lead into alienated concepts with weak connections to prior knowledge. A concept map visualizes the existing conceptual structure, and whenever new information is brought in, it will be placed in the map by clearly explicating its linkage to the previous concepts. In the Finnish mathematics education, such new knowledge is programming content that is integrated into elementary school mathematics in 2014 Finnish National Curriculum. This content is crystallized as the requirements of computational and algorithmic thinking, the utilization of respective data structures, and adequate amount of hands-on practice to internalize good coding conventions. This study examines secondary (N = 19) and higher education students (N = 10) and their conceptual knowledge of mathematics concentrating on the domain of algorithms in particular. The concept maps drawn by the students are evaluated using the SOLO taxonomy. To conclude, a consensus map of algorithms is represented and linked to the elementary mathematics syllabus. AB - This paper utilizes concept mapping as a tool for conscious and deliberate knowledge building in mathematics and its extension to algorithms. Currently, alleged defects in mathematics education are obvious: instead of conceptual elaboration, everyday praxis relies on routine computations that are likely to lead into alienated concepts with weak connections to prior knowledge. A concept map visualizes the existing conceptual structure, and whenever new information is brought in, it will be placed in the map by clearly explicating its linkage to the previous concepts. In the Finnish mathematics education, such new knowledge is programming content that is integrated into elementary school mathematics in 2014 Finnish National Curriculum. This content is crystallized as the requirements of computational and algorithmic thinking, the utilization of respective data structures, and adequate amount of hands-on practice to internalize good coding conventions. This study examines secondary (N = 19) and higher education students (N = 10) and their conceptual knowledge of mathematics concentrating on the domain of algorithms in particular. The concept maps drawn by the students are evaluated using the SOLO taxonomy. To conclude, a consensus map of algorithms is represented and linked to the elementary mathematics syllabus. KW - Concept Mapping KW - Meta-cognitive Skills KW - SOLO Taxonomy KW - Visualizations U2 - 10.13189/ujer.2018.061133 DO - 10.13189/ujer.2018.061133 M3 - Article VL - 6 SP - 2669 EP - 2678 JO - Universal Journal of Educational Research JF - Universal Journal of Educational Research SN - 2332-3205 IS - 11 ER - TY - JOUR T1 - Computing minimum rainbow and strong rainbow colorings of block graphs AU - Keranen, Melissa AU - Lauri, Juho PY - 2018 Y1 - 2018 N2 - A path in an edge-colored graph G is rainbow if no two edges of it are colored the same. The graph G is rainbowconnected if there is a rainbow path between every pair of vertices. If there is a rainbow shortest path between every pair of vertices, the graph G is strongly rainbow-connected. The minimum number of colors needed to make G rainbow-connected is known as the rainbow connection number of G, and is denoted by rc(G). Similarly, the minimum number of colors needed to make G strongly rainbow-connected is known as the strong rainbow connection number ofG, and is denoted by src(G). We prove that for every k ≥ 3, deciding whether src(G) ≤ k is NP-complete for split graphs, which form a subclass of chordal graphs. Furthermore, there exists no polynomial-time algorithm for approximating the strong rainbow connection number of an n-vertex split graph with a factor of n1-2-ϵ for any ϵ > 0 unless P = NP. We then turn our attention to block graphs, which also form a subclass of chordal graphs. We determine the strong rainbow connection number of block graphs, and show it can be computed in linear time. Finally, we provide a polynomial-time characterization of bridgeless block graphs with rainbow connection number at most 4. AB - A path in an edge-colored graph G is rainbow if no two edges of it are colored the same. The graph G is rainbowconnected if there is a rainbow path between every pair of vertices. If there is a rainbow shortest path between every pair of vertices, the graph G is strongly rainbow-connected. The minimum number of colors needed to make G rainbow-connected is known as the rainbow connection number of G, and is denoted by rc(G). Similarly, the minimum number of colors needed to make G strongly rainbow-connected is known as the strong rainbow connection number ofG, and is denoted by src(G). We prove that for every k ≥ 3, deciding whether src(G) ≤ k is NP-complete for split graphs, which form a subclass of chordal graphs. Furthermore, there exists no polynomial-time algorithm for approximating the strong rainbow connection number of an n-vertex split graph with a factor of n1-2-ϵ for any ϵ > 0 unless P = NP. We then turn our attention to block graphs, which also form a subclass of chordal graphs. We determine the strong rainbow connection number of block graphs, and show it can be computed in linear time. Finally, we provide a polynomial-time characterization of bridgeless block graphs with rainbow connection number at most 4. KW - Block graph KW - Computational complexity KW - Rainbow coloring U2 - 10.23638/DMTCS-20-1-22 DO - 10.23638/DMTCS-20-1-22 M3 - Article VL - 20 JO - Discrete Mathematics and Theoretical Computer Science JF - Discrete Mathematics and Theoretical Computer Science SN - 1462-7264 IS - 1 M1 - 22 ER - TY - JOUR T1 - Constructing Minimal Coverability Sets AU - Piipponen, Artturi AU - Valmari, Antti PY - 2016/3/4 Y1 - 2016/3/4 N2 - This publication addresses two bottlenecks in the construction of minimal coverability sets of Petri nets: the detection of situations where the marking of a place can be converted to ω, and the manipulation of the set A of maximal ω-markings that have been found so far. For the former, a technique is presented that consumes very little time in addition to what maintaining A consumes. It is based on Tarjan's algorithm for detecting maximal strongly connected components of a directed graph. For the latter, a data structure is introduced that resembles BDDs and Covering Sharing Trees, but has additional heuristics designed for the present use. Results from a few experiments are shown. They demonstrate significant savings in running time and varying savings in memory consumption compared to an earlier state-of-the-art technique. AB - This publication addresses two bottlenecks in the construction of minimal coverability sets of Petri nets: the detection of situations where the marking of a place can be converted to ω, and the manipulation of the set A of maximal ω-markings that have been found so far. For the former, a technique is presented that consumes very little time in addition to what maintaining A consumes. It is based on Tarjan's algorithm for detecting maximal strongly connected components of a directed graph. For the latter, a data structure is introduced that resembles BDDs and Covering Sharing Trees, but has additional heuristics designed for the present use. Results from a few experiments are shown. They demonstrate significant savings in running time and varying savings in memory consumption compared to an earlier state-of-the-art technique. KW - antichain data structure KW - coverability set KW - Tarjan's algorithm U2 - 10.3233/FI-2016-1319 DO - 10.3233/FI-2016-1319 M3 - Article VL - 143 SP - 393 EP - 414 JO - Fundamenta Informaticae JF - Fundamenta Informaticae SN - 0169-2968 IS - 3-4 ER - TY - JOUR T1 - Controller Design for Robust Output Regulation of Regular Linear Systems AU - Paunonen, L. PY - 2016 Y1 - 2016 N2 - We present three dynamic error feedback controllers for robust output regulation of regular linear systems. These controllers are (i) a minimal order robust controller for exponentially stable systems (ii) an observer-based robust controller and (iii) a new internal model based robust controller structure. In addition, we present two controllers that are by construction robust with respect to predefined classes of perturbations. The results are illustrated with an example where we study robust output tracking of a sinusoidal reference signal for a two-dimensional heat equation with boundary control and observation. AB - We present three dynamic error feedback controllers for robust output regulation of regular linear systems. These controllers are (i) a minimal order robust controller for exponentially stable systems (ii) an observer-based robust controller and (iii) a new internal model based robust controller structure. In addition, we present two controllers that are by construction robust with respect to predefined classes of perturbations. The results are illustrated with an example where we study robust output tracking of a sinusoidal reference signal for a two-dimensional heat equation with boundary control and observation. KW - Linear systems KW - Robustness KW - Robust output regulation KW - controller design KW - feedback KW - regular linear systems U2 - 10.1109/TAC.2015.2509439 DO - 10.1109/TAC.2015.2509439 M3 - Article VL - 61 SP - 2974 EP - 2986 JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 IS - 10 ER - TY - JOUR T1 - Cuts for 3-D magnetic scalar potentials T2 - Visualizing unintuitive surfaces arising from trivial knots AU - Stockrahm, Alex AU - Lahtinen, Valtteri AU - Kangas, Jari J.J. AU - Kotiuga, P. Robert PY - 2019 Y1 - 2019 N2 - A wealth of literature exists on computing and visualizing cuts for the magnetic scalar potential of a current carrying conductor via Finite Element Methods (FEM) and harmonic maps to the circle. By a cut we refer to an orientable surface bounded by a given current carrying path (such that the flux through it may be computed) that restricts contour integrals on a curl-zero vector field to those that do not link the current-carrying path, analogous to branch cuts of complex analysis. This work is concerned with a study of a peculiar contour that illustrates topologically unintuitive aspects of cuts obtained from a trivial loop and raises questions about the notion of an optimal cut. Specifically, an unknotted curve that bounds only high genus surfaces in its convex hull is analyzed. The current work considers the geometric realization as a current-carrying wire in order to construct a magnetic scalar potential. Moreover, we consider the problem of choosing an energy functional on the space of maps, suggesting an algorithm for computing cuts via minimizing a conformally invariant functional utilizing Newton iteration. AB - A wealth of literature exists on computing and visualizing cuts for the magnetic scalar potential of a current carrying conductor via Finite Element Methods (FEM) and harmonic maps to the circle. By a cut we refer to an orientable surface bounded by a given current carrying path (such that the flux through it may be computed) that restricts contour integrals on a curl-zero vector field to those that do not link the current-carrying path, analogous to branch cuts of complex analysis. This work is concerned with a study of a peculiar contour that illustrates topologically unintuitive aspects of cuts obtained from a trivial loop and raises questions about the notion of an optimal cut. Specifically, an unknotted curve that bounds only high genus surfaces in its convex hull is analyzed. The current work considers the geometric realization as a current-carrying wire in order to construct a magnetic scalar potential. Moreover, we consider the problem of choosing an energy functional on the space of maps, suggesting an algorithm for computing cuts via minimizing a conformally invariant functional utilizing Newton iteration. KW - Homology KW - Magnetic fields KW - Visualization U2 - 10.1016/j.camwa.2019.05.023 DO - 10.1016/j.camwa.2019.05.023 M3 - Article JO - Computers & Mathematics with Applications JF - Computers & Mathematics with Applications SN - 0898-1221 ER - TY - JOUR T1 - CytoSpectre T2 - A tool for spectral analysis of oriented structures on cellular and subcellular levels AU - Kartasalo, Kimmo AU - Polonen, Risto-Pekka AU - Ojala, Marisa AU - Rasku, Jyrki AU - Lekkala, Jukka AU - Aalto-Setälä, Katriina AU - Kallio, Pasi PY - 2015/10/26 Y1 - 2015/10/26 N2 - Background: Orientation and the degree of isotropy are important in many biological systems such as the sarcomeres of cardiomyocytes and other fibrillar structures of the cytoskeleton. Image based analysis of such structures is often limited to qualitative evaluation by human experts, hampering the throughput, repeatability and reliability of the analyses. Software tools are not readily available for this purpose and the existing methods typically rely at least partly on manual operation.Results: We developed CytoSpectre, an automated tool based on spectral analysis, allowing the quantification of orientation and also size distributions of structures in microscopy images. CytoSpectre utilizes the Fourier transform to estimate the power spectrum of an image and based on the spectrum, computes parameter values describing, among others, the mean orientation, isotropy and size of target structures. The analysis can be further tuned to focus on targets of particular size at cellular or subcellular scales. The software can be operated via a graphical user interface without any programming expertise. We analyzed the performance of CytoSpectre by extensive simulations using artificial images, by benchmarking against FibrilTool and by comparisons with manual measurements performed for real images by a panel of human experts. The software was found to be tolerant against noise and blurring and superior to FibrilTool when analyzing realistic targets with degraded image quality. The analysis of real images indicated general good agreement between computational and manual results while also revealing notable expert-to-expert variation. Moreover, the experiment showed that CytoSpectre can handle images obtained of different cell types using different microscopy techniques. Finally, we studied the effect of mechanical stretching on cardiomyocytes to demonstrate the software in an actual experiment and observed changes in cellular orientation in response to stretching.Conclusions: CytoSpectre, a versatile, easy-to-use software tool for spectral analysis of microscopy images was developed. The tool is compatible with most 2D images and can be used to analyze targets at different scales. We expect the tool to be useful in diverse applications dealing with structures whose orientation and size distributions are of interest. While designed for the biological field, the software could also be useful in non-biological applications. AB - Background: Orientation and the degree of isotropy are important in many biological systems such as the sarcomeres of cardiomyocytes and other fibrillar structures of the cytoskeleton. Image based analysis of such structures is often limited to qualitative evaluation by human experts, hampering the throughput, repeatability and reliability of the analyses. Software tools are not readily available for this purpose and the existing methods typically rely at least partly on manual operation.Results: We developed CytoSpectre, an automated tool based on spectral analysis, allowing the quantification of orientation and also size distributions of structures in microscopy images. CytoSpectre utilizes the Fourier transform to estimate the power spectrum of an image and based on the spectrum, computes parameter values describing, among others, the mean orientation, isotropy and size of target structures. The analysis can be further tuned to focus on targets of particular size at cellular or subcellular scales. The software can be operated via a graphical user interface without any programming expertise. We analyzed the performance of CytoSpectre by extensive simulations using artificial images, by benchmarking against FibrilTool and by comparisons with manual measurements performed for real images by a panel of human experts. The software was found to be tolerant against noise and blurring and superior to FibrilTool when analyzing realistic targets with degraded image quality. The analysis of real images indicated general good agreement between computational and manual results while also revealing notable expert-to-expert variation. Moreover, the experiment showed that CytoSpectre can handle images obtained of different cell types using different microscopy techniques. Finally, we studied the effect of mechanical stretching on cardiomyocytes to demonstrate the software in an actual experiment and observed changes in cellular orientation in response to stretching.Conclusions: CytoSpectre, a versatile, easy-to-use software tool for spectral analysis of microscopy images was developed. The tool is compatible with most 2D images and can be used to analyze targets at different scales. We expect the tool to be useful in diverse applications dealing with structures whose orientation and size distributions are of interest. While designed for the biological field, the software could also be useful in non-biological applications. KW - Orientation KW - Isotropy KW - Spectral analysis KW - Fourier transform KW - Power spectrum KW - Image analysis KW - Microscopy KW - Artificial images KW - Cardiomyocytes KW - Stretching KW - FAST FOURIER-TRANSFORM KW - PLURIPOTENT STEM-CELLS KW - QUANTITATIVE-ANALYSIS KW - AUTOMATED MEASUREMENT KW - MICROSCOPY IMAGES KW - CARDIOMYOCYTES KW - ORIENTATION KW - ALIGNMENT KW - DIFFERENTIATION KW - MATURATION UR - http://www.scopus.com/inward/record.url?scp=84958912496&partnerID=8YFLogxK U2 - 10.1186/s12859-015-0782-y DO - 10.1186/s12859-015-0782-y M3 - Article VL - 16 JO - BMC Bioinformatics JF - BMC Bioinformatics SN - 1471-2105 IS - 1 M1 - 344 ER - TY - JOUR T1 - DAMIT: a database of asteroid models AU - Durech, J. AU - Sidorin, V. AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1051/0004-6361/200912693 DO - 10.1051/0004-6361/200912693 M3 - Article VL - 513 SP - 1 EP - 13 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - A46 ER - TY - JOUR T1 - Data-based stochastic modeling of tree growth and structure formation AU - Potapov, Ilya AU - Järvenpää, Marko AU - Åkerblom, Markku AU - Raumonen, Pasi AU - Kaasalainen, Mikko PY - 2016 Y1 - 2016 N2 - We introduce a general procedure to match a stochastic functional-structural tree model (here LIGNUM augmented with stochastic rules) with real tree structures depicted by quantitative structure models (QSMs) based on terrestrial laser scanning. The matching is done by iteratively finding the maximum correspondence between the measured tree structure and the stochastic choices of the algorithm. First, we analyze the match to synthetic data (generated by the model itself), where the target values of the parameters to be estimated are known in advance, and show that the algorithm converges properly. We then carry out the procedure on real data obtaining a realistic model. We thus conclude that the proposed stochastic structure model (SSM) approach is a viable solution for formulating realistic plant models based on data and accounting for the stochastic influences. AB - We introduce a general procedure to match a stochastic functional-structural tree model (here LIGNUM augmented with stochastic rules) with real tree structures depicted by quantitative structure models (QSMs) based on terrestrial laser scanning. The matching is done by iteratively finding the maximum correspondence between the measured tree structure and the stochastic choices of the algorithm. First, we analyze the match to synthetic data (generated by the model itself), where the target values of the parameters to be estimated are known in advance, and show that the algorithm converges properly. We then carry out the procedure on real data obtaining a realistic model. We thus conclude that the proposed stochastic structure model (SSM) approach is a viable solution for formulating realistic plant models based on data and accounting for the stochastic influences. KW - Data fitting KW - Form diversity KW - Morphological plasticity KW - Plant model KW - Quantitative structure models KW - Stochastic functional-structural KW - Terrestrial lidar U2 - 10.14214/sf.1413 DO - 10.14214/sf.1413 M3 - Article VL - 50 JO - Silva Fennica JF - Silva Fennica SN - 0037-5330 IS - 1 M1 - 1413 ER - TY - JOUR T1 - Designing controllers with reduced order internal models AU - Paunonen, Lassi PY - 2015/3/1 Y1 - 2015/3/1 N2 - In this technical note we study robust output tracking for autonomous linear systems. We introduce a new approach to designing robust controllers using a recent observation that a full internal model is not always necessary for robustness. Especially this may be the case if the control law is only required to be robust with respect to a specific predetermined class of uncertainties in the parameters of the plant. The results are illustrated with an example on robust output tracking for coupled harmonic oscillators. AB - In this technical note we study robust output tracking for autonomous linear systems. We introduce a new approach to designing robust controllers using a recent observation that a full internal model is not always necessary for robustness. Especially this may be the case if the control law is only required to be robust with respect to a specific predetermined class of uncertainties in the parameters of the plant. The results are illustrated with an example on robust output tracking for coupled harmonic oscillators. UR - http://www.scopus.com/inward/record.url?scp=84923355671&partnerID=8YFLogxK U2 - 10.1109/TAC.2014.2329212 DO - 10.1109/TAC.2014.2329212 M3 - Article VL - 60 SP - 775 EP - 780 JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 IS - 3 M1 - 6826480 ER - TY - JOUR T1 - Detection of anomalies in radio tomography of asteroids: source count and forward errors AU - Pursiainen, S. AU - Kaasalainen, M. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-17

Publisher name: Pergamon PY - 2014 Y1 - 2014 U2 - 10.1016/j.pss.2014.04.017 DO - 10.1016/j.pss.2014.04.017 M3 - Article VL - 99 SP - 36 EP - 47 JO - Planetary and Space Science JF - Planetary and Space Science SN - 0032-0633 ER - TY - JOUR T1 - Detection of the YORP effect in asteroid (1620) Geographos AU - Durech, J. AU - Vokrouhlicky, D. AU - Kaasalainen, M. AU - Higgins, D. AU - Krugly, Y. AU - Gaftonyuk, N. AU - Shevchenko, V. AU - Chiorny, V. AU - Hamanowa, H. AU - Reddy, V. AU - Dyvig, R. N1 - Contribution: organisation=mat,FACT1=1 PY - 2008 Y1 - 2008 U2 - 10.1051/0004-6361:200810672 DO - 10.1051/0004-6361:200810672 M3 - Article VL - 489 SP - pp. L25-L28 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - 2 ER - TY - JOUR T1 - Device self-calibration in location systems using signal strength histograms AU - Laoudias, Christos AU - Piche, Robert AU - Panayiotou, Christos G. N1 - Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2013-07-29

Publisher name: Taylor & Francis PY - 2013 Y1 - 2013 U2 - 10.1080/17489725.2013.816792 DO - 10.1080/17489725.2013.816792 M3 - Article VL - 7 SP - 165 EP - 181 JO - Journal of Location Based Services JF - Journal of Location Based Services SN - 1748-9725 IS - 3 ER - TY - JOUR T1 - Dimensional Reduction of Electromagnetic Boundary Value Problems AU - Raumonen, Pasi AU - Suuriniemi, Saku AU - Kettunen, Lauri N1 - 50 % Matematiikka, 50 % Sähkömagnetiikka

Contribution: organisation=mat,FACT1=0.5

Contribution: organisation=ele smg,FACT2=0.5 PY - 2011 Y1 - 2011 U2 - 10.1186/1687-2770-2011-9 DO - 10.1186/1687-2770-2011-9 M3 - Article VL - 2011 SP - 1 EP - 25 JO - Boundary Value Problems JF - Boundary Value Problems SN - 1687-2762 M1 - 9 ER - TY - JOUR T1 - Directed structure at infinity for infinite-dimensional systems AU - Laakkonen, Petteri AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1080/00207179.2011.572999 DO - 10.1080/00207179.2011.572999 M3 - Article VL - 84 SP - 702 EP - 715 JO - International Journal of Control JF - International Journal of Control SN - 0020-7179 IS - 4 ER - TY - JOUR T1 - Discrete maximum principles for FE solutions of nonstationary diffusion-reaction problems with mixed boundary conditions AU - Farago, I. AU - Horvath, R. AU - Korotov, Sergey N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1002/num.20547 DO - 10.1002/num.20547 M3 - Article VL - 27 SP - 702 EP - 720 JO - Numerical Methods for Partial Differential Equations JF - Numerical Methods for Partial Differential Equations SN - 0749-159X IS - 3 ER - TY - JOUR T1 - DISCUS – The Deep Interior Scanning CubeSat mission to a rubble pile near-Earth asteroid AU - Bambach, Patrick AU - Deller, Jakob AU - Vilenius, Esa AU - Pursiainen, Sampsa AU - Takala, Mika AU - Braun, Hans Martin AU - Lentz, Harald AU - Wittig, Manfred PY - 2018/12 Y1 - 2018/12 N2 - We have performed an initial stage conceptual design study for the Deep Interior Scanning CubeSat (DISCUS), a tandem 6U CubeSat carrying a bistatic radar as the main payload. DISCUS will be operated either as an independent mission or accompanying a larger one. It is designed to determine the internal macroporosity of a 260–600 m diameter Near Earth Asteroid (NEA) from a few kilometers distance. The main goal will be to achieve a global penetration with a low-frequency signal as well as to analyze the scattering strength for various different penetration depths and measurement positions. Moreover, the measurements will be inverted through a computed radar tomography (CRT) approach. The scientific data provided by DISCUS would bring more knowledge of the internal configuration of rubble pile asteroids and their collisional evolution in the Solar System. It would also advance the design of future asteroid deflection concepts. We aim at a single-unit (1U) radar design equipped with a half-wavelength dipole antenna. The radar will utilize a stepped-frequency modulation technique the baseline of which was developed for ESA's technology projects GINGER and PIRA. The radar measurements will be used for CRT and shape reconstruction. The CubeSat will also be equipped with an optical camera system and laser altimeter to support navigation and shape reconstruction. We provide the details of the measurement methods to be applied along with the requirements derived from the known characteristics of rubble pile asteroids. Additionally, an initial design study of the platform and targets accessible within 20 lunar distances are presented. AB - We have performed an initial stage conceptual design study for the Deep Interior Scanning CubeSat (DISCUS), a tandem 6U CubeSat carrying a bistatic radar as the main payload. DISCUS will be operated either as an independent mission or accompanying a larger one. It is designed to determine the internal macroporosity of a 260–600 m diameter Near Earth Asteroid (NEA) from a few kilometers distance. The main goal will be to achieve a global penetration with a low-frequency signal as well as to analyze the scattering strength for various different penetration depths and measurement positions. Moreover, the measurements will be inverted through a computed radar tomography (CRT) approach. The scientific data provided by DISCUS would bring more knowledge of the internal configuration of rubble pile asteroids and their collisional evolution in the Solar System. It would also advance the design of future asteroid deflection concepts. We aim at a single-unit (1U) radar design equipped with a half-wavelength dipole antenna. The radar will utilize a stepped-frequency modulation technique the baseline of which was developed for ESA's technology projects GINGER and PIRA. The radar measurements will be used for CRT and shape reconstruction. The CubeSat will also be equipped with an optical camera system and laser altimeter to support navigation and shape reconstruction. We provide the details of the measurement methods to be applied along with the requirements derived from the known characteristics of rubble pile asteroids. Additionally, an initial design study of the platform and targets accessible within 20 lunar distances are presented. KW - Computed radar tomography KW - Deep-space CubeSat KW - Near earth asteroid KW - Radar KW - Rubble pile asteroid U2 - 10.1016/j.asr.2018.06.016 DO - 10.1016/j.asr.2018.06.016 M3 - Article VL - 62 SP - 3357 EP - 3368 JO - Advances in Space Research JF - Advances in Space Research SN - 0273-1177 IS - 12 ER - TY - JOUR T1 - Distribution of shape elongations of main belt asteroids derived from Pan-STARRS1 photometry AU - Cibulková, H. AU - Nortunen, H. AU - Ďurech, J. AU - Kaasalainen, M. AU - Vereš, P. AU - Jedicke, R. AU - Wainscoat, R. J. AU - Mommert, M. AU - Trilling, D. E. AU - Schunová-Lilly, E. AU - Magnier, E. A. AU - Waters, C. AU - Flewelling, H. PY - 2018/3/1 Y1 - 2018/3/1 N2 - Context. A considerable amount of photometric data is produced by surveys such as Pan-STARRS, LONEOS, WISE, or Catalina. These data are a rich source of information about the physical properties of asteroids. There are several possible approaches for using these data. Light curve inversion is a typical method that works with individual asteroids. Our approach in focusing on large groups of asteroids, such as dynamical families and taxonomic classes, is statistical; the data are not sufficient for individual models.Aim. Our aim is to study the distributions of shape elongation ba and the spin axis latitude β for various subpopulations of asteroids and to compare our results, based on Pan-STARRS1 survey, with statistics previously carried out using various photometric databases, such as Lowell and WISE.Methods. We used the LEADER algorithm to compare the ba and β distributions for various subpopulations of asteroids. The algorithm creates a cumulative distributive function (CDF) of observed brightness variations, and computes the ba and β distributions with analytical basis functions that yield the observed CDF. A variant of LEADER is used to solve the joint distributions for synthetic populations to test the validity of the method.Results. When comparing distributions of shape elongation for groups of asteroids with different diameters D, we found that there are no differences for D < 25 km. We also constructed distributions for asteroids with different rotation periods and revealed that the fastest rotators with P = 0 - 4 h are more spheroidal than the population with P = 4-8 h. AB - Context. A considerable amount of photometric data is produced by surveys such as Pan-STARRS, LONEOS, WISE, or Catalina. These data are a rich source of information about the physical properties of asteroids. There are several possible approaches for using these data. Light curve inversion is a typical method that works with individual asteroids. Our approach in focusing on large groups of asteroids, such as dynamical families and taxonomic classes, is statistical; the data are not sufficient for individual models.Aim. Our aim is to study the distributions of shape elongation ba and the spin axis latitude β for various subpopulations of asteroids and to compare our results, based on Pan-STARRS1 survey, with statistics previously carried out using various photometric databases, such as Lowell and WISE.Methods. We used the LEADER algorithm to compare the ba and β distributions for various subpopulations of asteroids. The algorithm creates a cumulative distributive function (CDF) of observed brightness variations, and computes the ba and β distributions with analytical basis functions that yield the observed CDF. A variant of LEADER is used to solve the joint distributions for synthetic populations to test the validity of the method.Results. When comparing distributions of shape elongation for groups of asteroids with different diameters D, we found that there are no differences for D < 25 km. We also constructed distributions for asteroids with different rotation periods and revealed that the fastest rotators with P = 0 - 4 h are more spheroidal than the population with P = 4-8 h. KW - asteroids KW - general KW - Methods KW - Minor planets KW - photometric KW - statistical KW - Techniques U2 - 10.1051/0004-6361/201731554 DO - 10.1051/0004-6361/201731554 M3 - Article VL - 611 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A86 ER - TY - JOUR T1 - Distribution of spin-axes longitudes and shape elongations of main-belt asteroids AU - Cibulkova, Helena AU - Durech, Josef AU - Vokrouhlicky, David AU - Kaasalainen, Mikko AU - Oszkiewicz, Dagmara A. PY - 2016/12 Y1 - 2016/12 U2 - 10.1051/0004-6361/201629192 DO - 10.1051/0004-6361/201629192 M3 - Article VL - 596 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A57 ER - TY - JOUR T1 - Dynamical tomography of gravitationally bound systems AU - Kaasalainen, M. N1 - Contribution: organisation=mat,FACT1=1 PY - 2008 Y1 - 2008 U2 - 10.3934/ipi.2008.2.527 DO - 10.3934/ipi.2008.2.527 M3 - Article VL - 2 SP - 527 EP - 546 JO - Inverse Problems and Imaging JF - Inverse Problems and Imaging SN - 1930-8337 IS - 4 ER - TY - JOUR T1 - Electroencephalography (EEG) forward modeling via H(div) finite element sources with focal interpolation AU - Pursiainen, S AU - Vorwerk, J AU - Wolters, C H PY - 2016/11/15 Y1 - 2016/11/15 N2 - The goal of this study is to develop focal, accurate and robust finite element method (FEM) based approaches which can predict the electric potential on the surface of the computational domain given its structure and internal primary source current distribution. While conducting an EEG evaluation, the placement of source currents to the geometrically complex grey matter compartment is a challenging but necessary task to avoid forward errors attributable to tissue conductivity jumps. Here, this task is approached via a mathematically rigorous formulation, in which the current field is modeled via divergence conforming H(div) basis functions. Both linear and quadratic functions are used while the potential field is discretized via the standard linear Lagrangian (nodal) basis. The resulting model includes dipolar sources which are interpolated into a random set of positions and orientations utilizing two alternative approaches: the position based optimization (PBO) and the mean position/orientation (MPO) method. These results demonstrate that the present dipolar approach can reach or even surpass, at least in some respects, the accuracy of two classical reference methods, the partial integration (PI) and St. Venant (SV) approach which utilize monopolar loads instead of dipolar currents. AB - The goal of this study is to develop focal, accurate and robust finite element method (FEM) based approaches which can predict the electric potential on the surface of the computational domain given its structure and internal primary source current distribution. While conducting an EEG evaluation, the placement of source currents to the geometrically complex grey matter compartment is a challenging but necessary task to avoid forward errors attributable to tissue conductivity jumps. Here, this task is approached via a mathematically rigorous formulation, in which the current field is modeled via divergence conforming H(div) basis functions. Both linear and quadratic functions are used while the potential field is discretized via the standard linear Lagrangian (nodal) basis. The resulting model includes dipolar sources which are interpolated into a random set of positions and orientations utilizing two alternative approaches: the position based optimization (PBO) and the mean position/orientation (MPO) method. These results demonstrate that the present dipolar approach can reach or even surpass, at least in some respects, the accuracy of two classical reference methods, the partial integration (PI) and St. Venant (SV) approach which utilize monopolar loads instead of dipolar currents. U2 - 10.1088/0031-9155/61/24/8502 DO - 10.1088/0031-9155/61/24/8502 M3 - Article VL - 61 SP - 8502 EP - 8520 JO - Physics in Medicine and Biology JF - Physics in Medicine and Biology SN - 0031-9155 IS - 24 ER - TY - JOUR T1 - Emptiness problems for distributed automata AU - Kuusisto, Antti AU - Reiter, Fabian PY - 2019 Y1 - 2019 N2 - We investigate the decidability of the emptiness problem for three classes of distributed automata. These devices operate on finite directed graphs, acting as networks of identical finite-state machines that communicate in an infinite sequence of synchronous rounds. The problem is shown to be decidable in LOGSPACE for a class of forgetful automata, where the nodes see the messages received from their neighbors but cannot remember their own state. When restricted to the appropriate families of graphs, these forgetful automata are equivalent to classical finite word automata, but strictly more expressive than finite tree automata. On the other hand, we also show that the emptiness problem is undecidable in general. This already holds for two heavily restricted classes of distributed automata: those that reject immediately if they receive more than one message per round, and those whose state diagram must be acyclic except for self-loops. Additionally, to demonstrate the flexibility of distributed automata in simulating different models of computation, we provide a characterization of constraint satisfaction problems by identifying a class of automata with exactly the same computational power. AB - We investigate the decidability of the emptiness problem for three classes of distributed automata. These devices operate on finite directed graphs, acting as networks of identical finite-state machines that communicate in an infinite sequence of synchronous rounds. The problem is shown to be decidable in LOGSPACE for a class of forgetful automata, where the nodes see the messages received from their neighbors but cannot remember their own state. When restricted to the appropriate families of graphs, these forgetful automata are equivalent to classical finite word automata, but strictly more expressive than finite tree automata. On the other hand, we also show that the emptiness problem is undecidable in general. This already holds for two heavily restricted classes of distributed automata: those that reject immediately if they receive more than one message per round, and those whose state diagram must be acyclic except for self-loops. Additionally, to demonstrate the flexibility of distributed automata in simulating different models of computation, we provide a characterization of constraint satisfaction problems by identifying a class of automata with exactly the same computational power. KW - Distributed computing KW - Emptiness problem KW - Finite automata U2 - 10.1016/j.ic.2019.104503 DO - 10.1016/j.ic.2019.104503 M3 - Article JO - Information and Computation JF - Information and Computation SN - 0890-5401 M1 - 104503 ER - TY - JOUR T1 - Energy conversion efficiency of the pumping kite wind generator AU - Argatov, Ivan AU - Silvennoinen, Risto N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1016/j.renene.2009.09.006 DO - 10.1016/j.renene.2009.09.006 M3 - Article VL - 35 SP - 1052 EP - 1060 JO - Renewable Energy JF - Renewable Energy SN - 0960-1481 ER - TY - JOUR T1 - Equivalence of Set- and Bag-Valued Orbits AU - Ruohonen, Keijo N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 M3 - Article VL - 14 SP - 247 EP - 253 JO - Journal of Automata, Languages and Combinatorics JF - Journal of Automata, Languages and Combinatorics SN - 1430-189X IS - 3/4 ER - TY - JOUR T1 - Estimation of above-ground biomass of large tropical trees with terrestrial LiDAR AU - Gonzalez de Tanago, Jose AU - Lau, Alvaro AU - Bartholomeus, Harm AU - Herold, Martin AU - Avitabile, Valerio AU - Raumonen, Pasi AU - Martius, Christopher AU - Goodman, Rosa AU - Disney, Mathias AU - Manuri, Solichin AU - Burt, Andrew AU - Calders, Kim PY - 2017/11/13 Y1 - 2017/11/13 N2 - 1. Tropical forest biomass is a crucial component of global carbon emission estimations. However, calibration and validation of such estimates require accurate and effective methods to estimate in situ above-ground biomass (AGB). Present methods rely on allometric models that are highly uncertain for large tropical trees. Terrestrial laser scanning (TLS) tree modelling has demonstrated to be more accurate than these models to infer forest AGB. Nevertheless, applying TLS methods on tropical large trees is still challenging. We propose a method to estimate AGB of large tropical trees by three-dimensional (3D) tree modelling of TLS point clouds.2. Twenty-nine plots were scanned with a TLS in three study sites (Peru, Indonesia and Guyana). We identified the largest tree per plot (mean diameter at breast height of 73.5 cm), extracted its point cloud and calculated its volume by 3D modelling its structure using quantitative structure models (QSM) and converted to AGB using species-specific wood density. We also estimated AGB using pantropical and local allometric models. To assess the accuracy of our and allometric methods, we harvest the trees and took destructive measurements.3. AGB estimates by the TLS–QSM method showed the best agreement in comparison to destructive harvest measurements (28.37% coefficient of variation of root mean square error [CV-RMSE] and concordance correlation coefficient [CCC] of 0.95), outperforming the pantropical allometric models tested (35.6%–54.95% CV-RMSE and CCC of 0.89–0.73). TLS–QSM showed also the lowest bias (overall underestimation of 3.7%) and stability across tree size range, contrasting with the allometric models that showed a systematic bias (overall underestimation ranging 15.2%–35.7%) increasing linearly with tree size. The TLS–QSM method also provided accurate tree wood volume estimates (CV RMSE of 23.7%) with no systematic bias regardless the tree structural characteristics.4. Our TLS–QSM method accounts for individual tree biophysical structure more effectively than allometric models, providing more accurate and less biased AGB estimates for large tropical trees, independently of their morphology. This non-destructive method can be further used for testing and calibrating new allometric models, reducing the current under-representation of large trees in and enhancing present and past estimates of forest biomass and carbon emissions from tropical forests. AB - 1. Tropical forest biomass is a crucial component of global carbon emission estimations. However, calibration and validation of such estimates require accurate and effective methods to estimate in situ above-ground biomass (AGB). Present methods rely on allometric models that are highly uncertain for large tropical trees. Terrestrial laser scanning (TLS) tree modelling has demonstrated to be more accurate than these models to infer forest AGB. Nevertheless, applying TLS methods on tropical large trees is still challenging. We propose a method to estimate AGB of large tropical trees by three-dimensional (3D) tree modelling of TLS point clouds.2. Twenty-nine plots were scanned with a TLS in three study sites (Peru, Indonesia and Guyana). We identified the largest tree per plot (mean diameter at breast height of 73.5 cm), extracted its point cloud and calculated its volume by 3D modelling its structure using quantitative structure models (QSM) and converted to AGB using species-specific wood density. We also estimated AGB using pantropical and local allometric models. To assess the accuracy of our and allometric methods, we harvest the trees and took destructive measurements.3. AGB estimates by the TLS–QSM method showed the best agreement in comparison to destructive harvest measurements (28.37% coefficient of variation of root mean square error [CV-RMSE] and concordance correlation coefficient [CCC] of 0.95), outperforming the pantropical allometric models tested (35.6%–54.95% CV-RMSE and CCC of 0.89–0.73). TLS–QSM showed also the lowest bias (overall underestimation of 3.7%) and stability across tree size range, contrasting with the allometric models that showed a systematic bias (overall underestimation ranging 15.2%–35.7%) increasing linearly with tree size. The TLS–QSM method also provided accurate tree wood volume estimates (CV RMSE of 23.7%) with no systematic bias regardless the tree structural characteristics.4. Our TLS–QSM method accounts for individual tree biophysical structure more effectively than allometric models, providing more accurate and less biased AGB estimates for large tropical trees, independently of their morphology. This non-destructive method can be further used for testing and calibrating new allometric models, reducing the current under-representation of large trees in and enhancing present and past estimates of forest biomass and carbon emissions from tropical forests. U2 - 10.1111/2041-210X.12904 DO - 10.1111/2041-210X.12904 M3 - Article JO - Methods in Ecology and Evolution JF - Methods in Ecology and Evolution SN - 2041-210X ER - TY - JOUR T1 - E-type asteroid Steins as imaged by OSIRIS on board Rosetta AU - Keller, H.U. AU - Barbieri, C. AU - Koschny, D. AU - Lamy, P. AU - Rickman, H. AU - Rodrigo, R. AU - Sierks, H. AU - A'Hearn, M.F. AU - Angrilli, F. AU - Barucci, M.A. AU - Bertaux, J.-L. AU - Cremonese, G. AU - Da Deppo, V. AU - Davidsson, B. AU - De Cecco, M. AU - Debei, S. AU - Fornasier, S. AU - Fulle, M. AU - Groussin, O. AU - Gutierrez, P.J. AU - Hviid, S.F. AU - Ip, W.-H. AU - Jorda, L. AU - Knollenberg, J. AU - Kramm, J.R. AU - Kuhrt, E. AU - Kuppers, M. AU - Lara, L.-M. AU - Lazzarin, M. AU - Lopez Moreno, J. AU - Marzari, F. AU - Michalik, H. AU - Naletto, G. AU - Sabau, L. AU - Thomas, N. AU - Wenzel, K.-P. AU - Bertini, I. AU - Besse, S. AU - Ferri, F. AU - Kaasalainen, Mikko AU - Lowry, S. AU - Marchi, S. AU - Mottola, S. AU - Sabolo, W. AU - Schröder, S.E. AU - Spjuth, S. AU - Vernazza, P. N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1126/science.1179559 DO - 10.1126/science.1179559 M3 - Article VL - 327 SP - 190 EP - 193 JO - Science JF - Science SN - 0036-8075 IS - 5962 ER - TY - JOUR T1 - Fair testing and stubborn sets AU - Valmari, Antti AU - Vogler, Walter PY - 2018 Y1 - 2018 N2 - Partial order methods alleviate state explosion by considering only a subset of actions in each constructed state. The choice of the subset depends on the properties that the method promises to preserve. Many methods have been developed ranging from deadlock-preserving to CTL(Formula presented.)-preserving and divergence-sensitive branching bisimilarity preserving. The less the method preserves, the smaller state spaces it constructs. Fair testing equivalence unifies deadlocks with livelocks that cannot be exited and ignores the other livelocks. It is the weakest congruence that preserves whether or not the system may enter a livelock that it cannot leave. We prove that a method that was designed for trace equivalence also preserves fair testing equivalence. We demonstrate its effectiveness on a protocol with a connection and data transfer phase. This is the first practical partial order method that deals with a practical fairness assumption. AB - Partial order methods alleviate state explosion by considering only a subset of actions in each constructed state. The choice of the subset depends on the properties that the method promises to preserve. Many methods have been developed ranging from deadlock-preserving to CTL(Formula presented.)-preserving and divergence-sensitive branching bisimilarity preserving. The less the method preserves, the smaller state spaces it constructs. Fair testing equivalence unifies deadlocks with livelocks that cannot be exited and ignores the other livelocks. It is the weakest congruence that preserves whether or not the system may enter a livelock that it cannot leave. We prove that a method that was designed for trace equivalence also preserves fair testing equivalence. We demonstrate its effectiveness on a protocol with a connection and data transfer phase. This is the first practical partial order method that deals with a practical fairness assumption. KW - Fair testing equivalence KW - Fairness KW - Partial order methods KW - Progress KW - Stubborn sets U2 - 10.1007/s10009-017-0481-2 DO - 10.1007/s10009-017-0481-2 M3 - Article SP - 589 EP - 610 JO - International Journal on Software Tools for Technology Transfer JF - International Journal on Software Tools for Technology Transfer SN - 1433-2779 ER - TY - JOUR T1 - Far-Field Inversion for the Deep Interior Scanning CubeSat AU - Takala, M. AU - Bambach, P. AU - Deller, J. AU - Vilenius, E. AU - Wittig, M. AU - Lentz, H. AU - Braun, H. M. AU - Kaasalainen, M. AU - Pursiainen, S. PY - 2018 Y1 - 2018 N2 - This study aims at advancing mathematical and computational techniques for reconstructing the interior structure of a small Solar System body via Computed Radar Tomography (CRT). We introduce a far-field model for full-wave CRT and validate it numerically for an orbiting distance of 5 km using a synthetic 3D target asteroid and sparse limited-angle data. As a potential future application of the proposed method, we consider the Deep Interior Scanning CUbeSat (DISCUS) concept in which the goal is to localize macroporosities inside a rubble pile near-Earth asteroid with two small spacecraft carrying a bistatic radar. AB - This study aims at advancing mathematical and computational techniques for reconstructing the interior structure of a small Solar System body via Computed Radar Tomography (CRT). We introduce a far-field model for full-wave CRT and validate it numerically for an orbiting distance of 5 km using a synthetic 3D target asteroid and sparse limited-angle data. As a potential future application of the proposed method, we consider the Deep Interior Scanning CUbeSat (DISCUS) concept in which the goal is to localize macroporosities inside a rubble pile near-Earth asteroid with two small spacecraft carrying a bistatic radar. KW - Cathode ray tubes KW - Computed Radar Tomography KW - Extraterrestrial measurements KW - Far-Field Measurements KW - Frequency measurement KW - Inverse Imaging KW - Near-Earth Asteroids KW - Radar KW - Small Solar System Bodies KW - Space vehicles U2 - 10.1109/TAES.2018.2874755 DO - 10.1109/TAES.2018.2874755 M3 - Article JO - IEEE Transactions on Aerospace and Electronic Systems JF - IEEE Transactions on Aerospace and Electronic Systems SN - 0018-9251 ER - TY - JOUR T1 - Fast automatic precision tree models from terrestrial laser scanner data AU - Raumonen, Pasi AU - Kaasalainen, Mikko AU - Åkerblom, Markku AU - Kaasalainen, Sanna AU - Kaartinen, Harri AU - Vastaranta, Mikko AU - Holopainen, Markus AU - Disney, Mathia AU - Lewis, Philip N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-07-29

Publisher name: MDPI PY - 2013 Y1 - 2013 U2 - 10.3390/rs5020491 DO - 10.3390/rs5020491 M3 - Article VL - 5 SP - 491 EP - 520 JO - Remote Sensing JF - Remote Sensing SN - 2072-4292 IS - 2 ER - TY - JOUR T1 - Finite-dimensional regulators for a class of regular hyperbolic PDE systems AU - Xu, Xiadong AU - Pohjolainen, Seppo AU - Dubljevic, Stevan PY - 2017/8/30 Y1 - 2017/8/30 N2 - In this paper, the output regulation problem is addressed for a class of linear hyperbolic infinite-dimensional systems with spatially varying coefficients modelling a large class of convection-dominated transport reaction systems. In particular, distributed parameter systems with bounded input and unbounded output operators are considered. First, we demonstrate a general conclusion about the exponential stability of the considered system by relating the stability to the solution of an associated differential equation. Based on the assumption that the hyperbolic system satisfies the exponential stability conditions, the main manuscript contribution is the development of two novel finite-dimensional regulators, output and error feedback regulators, such that the controlled output of the plant tracks a reference signal generated by a known signal process (exosystem). In order to guarantee the feasibility of the proposed regulators, the solvability of the corresponding Sylvester equations is discussed and the solvability conditions are provided. Finally, simulations of output regulation of an axial dispersion reactor and a relevant numerical example illustrate the main results and performance of the proposed regulators synthesis. AB - In this paper, the output regulation problem is addressed for a class of linear hyperbolic infinite-dimensional systems with spatially varying coefficients modelling a large class of convection-dominated transport reaction systems. In particular, distributed parameter systems with bounded input and unbounded output operators are considered. First, we demonstrate a general conclusion about the exponential stability of the considered system by relating the stability to the solution of an associated differential equation. Based on the assumption that the hyperbolic system satisfies the exponential stability conditions, the main manuscript contribution is the development of two novel finite-dimensional regulators, output and error feedback regulators, such that the controlled output of the plant tracks a reference signal generated by a known signal process (exosystem). In order to guarantee the feasibility of the proposed regulators, the solvability of the corresponding Sylvester equations is discussed and the solvability conditions are provided. Finally, simulations of output regulation of an axial dispersion reactor and a relevant numerical example illustrate the main results and performance of the proposed regulators synthesis. KW - Hyperbolic PDE systems, finite-dimensional regulators, output feedback regulator, Sylvester equation U2 - 10.1080/00207179.2017.1369575 DO - 10.1080/00207179.2017.1369575 M3 - Article SP - 1 EP - 18 JO - International Journal of Control JF - International Journal of Control SN - 0020-7179 ER - TY - JOUR T1 - Finite element analysis of trees in the wind based on terrestrial laser scanning data AU - Jackson, T. AU - Shenkin, A. AU - Wellpott, A. AU - Calders, K. AU - Origo, N. AU - Disney, M. AU - Burt, A. AU - Raumonen, P. AU - Gardiner, B. AU - Herold, M. AU - Fourcaud, T. AU - Malhi, Y. PY - 2019/2/15 Y1 - 2019/2/15 N2 - Wind damage is an important driver of forest structure and dynamics, but it is poorly understood in natural broadleaf forests. This paper presents a new approach in the study of wind damage: combining terrestrial laser scanning (TLS) data and finite element analysis. Recent advances in tree reconstruction from TLS data allowed us to accurately represent the 3D geometry of a tree in a mechanical simulation, without the need for arduous manual mapping or simplifying assumptions about tree shape. We used this simulation to predict the mechanical strains produced on the trunks of 21 trees in Wytham Woods, UK, and validated it using strain data measured on these same trees. For a subset of five trees near the anemometer, the model predicted a five-minute time-series of strain with a mean cross-correlation coefficient of 0.71, when forced by the locally measured wind speed data. Additionally, the maximum strain associated with a 5 ms−1 or 15 ms-1 wind speed was well predicted by the model (N = 17, R2 = 0.81 and R2 = 0.79, respectively). We also predicted the critical wind speed at which the trees will break from both the field data and models and find a good overall agreement (N = 17, R2 = 0.40). Finally, the model predicted the correct trend in the fundamental frequencies of the trees (N = 20, R2 = 0.38) although there was a systematic underprediction, possibly due to the simplified treatment of material properties in the model. The current approach relies on local wind data, so must be combined with wind flow modelling to be applicable at the landscape-scale or over complex terrain. This approach is applicable at the plot level and could also be applied to open-grown trees, such as in cities or parks. AB - Wind damage is an important driver of forest structure and dynamics, but it is poorly understood in natural broadleaf forests. This paper presents a new approach in the study of wind damage: combining terrestrial laser scanning (TLS) data and finite element analysis. Recent advances in tree reconstruction from TLS data allowed us to accurately represent the 3D geometry of a tree in a mechanical simulation, without the need for arduous manual mapping or simplifying assumptions about tree shape. We used this simulation to predict the mechanical strains produced on the trunks of 21 trees in Wytham Woods, UK, and validated it using strain data measured on these same trees. For a subset of five trees near the anemometer, the model predicted a five-minute time-series of strain with a mean cross-correlation coefficient of 0.71, when forced by the locally measured wind speed data. Additionally, the maximum strain associated with a 5 ms−1 or 15 ms-1 wind speed was well predicted by the model (N = 17, R2 = 0.81 and R2 = 0.79, respectively). We also predicted the critical wind speed at which the trees will break from both the field data and models and find a good overall agreement (N = 17, R2 = 0.40). Finally, the model predicted the correct trend in the fundamental frequencies of the trees (N = 20, R2 = 0.38) although there was a systematic underprediction, possibly due to the simplified treatment of material properties in the model. The current approach relies on local wind data, so must be combined with wind flow modelling to be applicable at the landscape-scale or over complex terrain. This approach is applicable at the plot level and could also be applied to open-grown trees, such as in cities or parks. KW - Critical wind speed KW - Finite element analysis KW - Resonant frequency KW - Terrestrial laser scanning KW - TLS KW - Wind damage U2 - 10.1016/j.agrformet.2018.11.014 DO - 10.1016/j.agrformet.2018.11.014 M3 - Article VL - 265 SP - 137 EP - 144 JO - Agricultural and Forest Meteorology JF - Agricultural and Forest Meteorology SN - 0168-1923 ER - TY - JOUR T1 - Flexible Identification Procedure for Thermodynamic Constitutive Models for Magnetostrictive Materials AU - Rasilo, Paavo AU - Singh, Deepak AU - Jeronen, Juha AU - Aydin, Ugur AU - Martin, Floran AU - Belahcen, Anouar AU - Daniel, Laurent AU - Kouhia, Reijo PY - 2019 Y1 - 2019 N2 - We present a novel approach for identifying a multiaxial thermodynamic magneto-mechanical constitutive law by direct bi- or trivariate spline interpolation from available magnetization and magnetostriction data. Reference data are first produced with a multiscale model in the case of a magnetic field and uniaxial and shear stresses. The thermodynamic model fits well to the results of the multiscale model, after which the models are compared under complex multiaxial loadings. A surprisingly good agreement between the two models is found, but some differences in the magnetostrictive behaviour are also pointed out. Finally, the model is fitted to measurement results from an electrical steel sheet. The spline-based constitutive law overcomes several drawbacks of analytical approaches used earlier. The presented models and measurement results are openly available. AB - We present a novel approach for identifying a multiaxial thermodynamic magneto-mechanical constitutive law by direct bi- or trivariate spline interpolation from available magnetization and magnetostriction data. Reference data are first produced with a multiscale model in the case of a magnetic field and uniaxial and shear stresses. The thermodynamic model fits well to the results of the multiscale model, after which the models are compared under complex multiaxial loadings. A surprisingly good agreement between the two models is found, but some differences in the magnetostrictive behaviour are also pointed out. Finally, the model is fitted to measurement results from an electrical steel sheet. The spline-based constitutive law overcomes several drawbacks of analytical approaches used earlier. The presented models and measurement results are openly available. U2 - 10.1098/rspa.2018.0280 DO - 10.1098/rspa.2018.0280 M3 - Article JO - Proceedings of the Royal Society A: Mathematical Physical and Engineering Sciences JF - Proceedings of the Royal Society A: Mathematical Physical and Engineering Sciences SN - 1364-5021 M1 - 20180280 ER - TY - JOUR T1 - Forecasting the diffusion of innovation: A stochastic bass model with log-normal and mean-reverting error process AU - Kanniainen, Juho AU - Mäkinen, Saku AU - Piche, Robert AU - Chakrabarti, Alok N1 - Contribution: organisation=tta,FACT1=0.75

Contribution: organisation=mat,FACT2=0.25 PY - 2011 Y1 - 2011 N2 - Forecasting the diffusion of innovations plays a major role in managing technology development and in engineering management overall. In this paper, we extend the conventional Bass model stochastically by specifying the error process of sales as log-normal and mean-reverting. Our model satisfies the following reasonable properties, which are generally ignored in the existing literature: sales cannot be negative, the error process can have a memory, and sales fluctuate more when they are high and less when they are low. The conventional and widely used model that assumes normally distributed error term does not have these properties. We address how to forecast properly under the log-normal and mean-reverting error process, and show analytically and numerically that in our extended model sales forecasts can substantially alter conventional Bass forecasts. We also analyze the model empirically, showing that our extension can improve the accuracy of future sales forecasts. AB - Forecasting the diffusion of innovations plays a major role in managing technology development and in engineering management overall. In this paper, we extend the conventional Bass model stochastically by specifying the error process of sales as log-normal and mean-reverting. Our model satisfies the following reasonable properties, which are generally ignored in the existing literature: sales cannot be negative, the error process can have a memory, and sales fluctuate more when they are high and less when they are low. The conventional and widely used model that assumes normally distributed error term does not have these properties. We address how to forecast properly under the log-normal and mean-reverting error process, and show analytically and numerically that in our extended model sales forecasts can substantially alter conventional Bass forecasts. We also analyze the model empirically, showing that our extension can improve the accuracy of future sales forecasts. U2 - 10.1109/TEM.2010.2048912 DO - 10.1109/TEM.2010.2048912 M3 - Article VL - 99 SP - 1 EP - 22 JO - IEEE Transactions on Engineering Management JF - IEEE Transactions on Engineering Management SN - 0018-9391 ER - TY - JOUR T1 - Formula size games for modal logic and mu-calculus AU - Hella, Lauri T AU - Vilander, Miikka S N1 - INT=comp."Hella, Lauri" PY - 2019/12/13 Y1 - 2019/12/13 N2 - We propose a new version of formula size game for modal logic. The game characterizes the equivalence of pointed Kripke models up to formulas of given numbers of modal operators and binary connectives. Our game is similar to the well-known Adler–Immerman game. However, due to a crucial difference in the definition of positions of the game, its winning condition is simpler, and the second player does not have a trivial optimal strategy. Thus, unlike the Adler–Immerman game, our game is a genuine two-person game. We illustrate the use of the game by proving a non-elementary succinctness gap between bisimulation invariant first-order logic FO and (basic) modal logic ML. We also present a version of the game for the modal μ-calculus Lμ and show that FO is also non-elementarily more succinct than Lμ. AB - We propose a new version of formula size game for modal logic. The game characterizes the equivalence of pointed Kripke models up to formulas of given numbers of modal operators and binary connectives. Our game is similar to the well-known Adler–Immerman game. However, due to a crucial difference in the definition of positions of the game, its winning condition is simpler, and the second player does not have a trivial optimal strategy. Thus, unlike the Adler–Immerman game, our game is a genuine two-person game. We illustrate the use of the game by proving a non-elementary succinctness gap between bisimulation invariant first-order logic FO and (basic) modal logic ML. We also present a version of the game for the modal μ-calculus Lμ and show that FO is also non-elementarily more succinct than Lμ. KW - succinctness KW - formula size game KW - modal logic KW - modal mu-calculus KW - bisimulation invariant first-order logic U2 - 10.1093/logcom/exz025 DO - 10.1093/logcom/exz025 M3 - Article JO - JOURNAL OF LOGIC AND COMPUTATION JF - JOURNAL OF LOGIC AND COMPUTATION SN - 0955-792X M1 - exz025 ER - TY - JOUR T1 - Forward and Inverse Effects of the Complete Electrode Model in Neonatal EEG AU - Pursiainen, Sampsa AU - Lew, Seok AU - Wolters, Carsten Hermann N1 - Copyright © 2016, Journal of Neurophysiology. PY - 2017/3 Y1 - 2017/3 N2 - This paper investigates finite element method (FEM) based modeling in the context of neonatal electroencephalography (EEG). In particular, the focus lies on electrode boundary conditions. We compare the complete electrode model (CEM) to the point electrode model (PEM), which is the current standard in EEG. In the CEM, the voltage experienced by an electrode is modeled more realistically as the integral average of the potential distribution over its contact surface, whereas the PEM relies on a point value. Consequently, the CEM takes into account the sub-electrode shunting currents which are absent in the PEM. In this study, we aim to find out how the electrode voltage predicted by these two models differ, if standard size electrodes are attached to a head of a neonate. Additionally, we study voltages and voltage variation on electrode surfaces with two source locations: (A) next to the 5-th electrode and (B) directly under the frontal fontanel. A realistic model of a neonatal head including a skull with fontanels and sutures is used. Based on the results, the forward simulation differences between CEM and PEM are in general small, but significant outliers can occur in the vicinity of the electrodes. The CEM can be considered as an integral part of the outer head model. The outcome of this study helps understanding volume conduction of neonatal EEG as it enlightens the role of advanced skull and electrode modeling in forward and inverse computations. AB - This paper investigates finite element method (FEM) based modeling in the context of neonatal electroencephalography (EEG). In particular, the focus lies on electrode boundary conditions. We compare the complete electrode model (CEM) to the point electrode model (PEM), which is the current standard in EEG. In the CEM, the voltage experienced by an electrode is modeled more realistically as the integral average of the potential distribution over its contact surface, whereas the PEM relies on a point value. Consequently, the CEM takes into account the sub-electrode shunting currents which are absent in the PEM. In this study, we aim to find out how the electrode voltage predicted by these two models differ, if standard size electrodes are attached to a head of a neonate. Additionally, we study voltages and voltage variation on electrode surfaces with two source locations: (A) next to the 5-th electrode and (B) directly under the frontal fontanel. A realistic model of a neonatal head including a skull with fontanels and sutures is used. Based on the results, the forward simulation differences between CEM and PEM are in general small, but significant outliers can occur in the vicinity of the electrodes. The CEM can be considered as an integral part of the outer head model. The outcome of this study helps understanding volume conduction of neonatal EEG as it enlightens the role of advanced skull and electrode modeling in forward and inverse computations. U2 - 10.1152/jn.00427.2016 DO - 10.1152/jn.00427.2016 M3 - Article VL - 117 SP - 876 EP - 884 JO - Journal of Neurophysiology JF - Journal of Neurophysiology SN - 0022-3077 IS - 3 ER - TY - JOUR T1 - Frequency domain robust regulation of signals generated by an infinite-dimensional exosystem AU - Laakkonen, Petteri AU - Pohjolainen, Seppo PY - 2015 Y1 - 2015 N2 - This paper deals with frequency domain robust regulation of signals generated by an infinite-dimensional exosystem. The problem is formulated and the stability types are chosen so that one can generalize the existing finite-dimensional theory to more general classes of infinite-dimensional systems and signals. The main results of this article are extensions of the internal model principle, of a necessary and sufficient solvability condition for the robust regulation problem, and of Davison's simple servo compensator for stable plants in the chosen algebraic framework. AB - This paper deals with frequency domain robust regulation of signals generated by an infinite-dimensional exosystem. The problem is formulated and the stability types are chosen so that one can generalize the existing finite-dimensional theory to more general classes of infinite-dimensional systems and signals. The main results of this article are extensions of the internal model principle, of a necessary and sufficient solvability condition for the robust regulation problem, and of Davison's simple servo compensator for stable plants in the chosen algebraic framework. KW - Frequency domain KW - Infinite-dimensional exosystems KW - Infinite-dimensional systems KW - Internal model KW - Robust regulation UR - http://www.scopus.com/inward/record.url?scp=84923923144&partnerID=8YFLogxK U2 - 10.1137/130950057 DO - 10.1137/130950057 M3 - Article VL - 53 SP - 139 EP - 166 JO - SIAM Journal on Control and Optimization JF - SIAM Journal on Control and Optimization SN - 0363-0129 IS - 1 ER - TY - JOUR T1 - Function classes and relational constraints stable under compositions with clones AU - Couceiro, M. AU - Foldes, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 M3 - Article VL - 29 SP - 109 EP - 121 JO - Discussiones Mathematicae - General Algebra and Applications JF - Discussiones Mathematicae - General Algebra and Applications SN - 1509-9415 ER - TY - JOUR T1 - Fundamental solution of k-hyperbolic harmonic functions in odd spaces AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki PY - 2015/4/13 Y1 - 2015/4/13 N2 - We study k-hyperbolic harmonic functions in the upper half space . The operator is the Laplace-Beltrami operator with respect to the Riemannian metric . In case k = n - 1 the Riemannian metric is the hyperbolic distance of Poincare upper half space. The proposed functions are connected to the axially symmetric potentials studied notably by Weinstein, Huber and Leutwiler. We present the fundamental solution in case n is even using the hyperbolic metric. The main tool is the transformation of k-hyperbolic harmonic functions to eigenfunctions of the hyperbolic Laplace operator. AB - We study k-hyperbolic harmonic functions in the upper half space . The operator is the Laplace-Beltrami operator with respect to the Riemannian metric . In case k = n - 1 the Riemannian metric is the hyperbolic distance of Poincare upper half space. The proposed functions are connected to the axially symmetric potentials studied notably by Weinstein, Huber and Leutwiler. We present the fundamental solution in case n is even using the hyperbolic metric. The main tool is the transformation of k-hyperbolic harmonic functions to eigenfunctions of the hyperbolic Laplace operator. UR - http://www.scopus.com/inward/record.url?scp=84928019119&partnerID=8YFLogxK U2 - 10.1088/1742-6596/597/1/012034 DO - 10.1088/1742-6596/597/1/012034 M3 - Article VL - 597 JO - Journal of Physics: Conference Series JF - Journal of Physics: Conference Series SN - 1742-6588 IS - 1 M1 - 012034 ER - TY - JOUR T1 - Further hardness results on rainbow and strong rainbow connectivity AU - Lauri, Juho PY - 2016 Y1 - 2016 N2 - A path in an edge-colored graph is rainbow if no two edges of it are colored the same. The graph is said to be rainbow connected if there is a rainbow path between every pair of vertices. If there is a rainbow shortest path between every pair of vertices, the graph is strong rainbow connected. We consider the complexity of the problem of deciding if a given edge-colored graph is rainbow or strong rainbow connected. These problems are called Rainbow connectivity and Strong rainbow connectivity, respectively. We prove both problems remain NP-complete on interval outerplanar graphs and k-regular graphs for k≥3. Previously, no graph class was known where the complexity of the two problems would differ. We show that for block graphs, which form a subclass of chordal graphs, Rainbow connectivity is NP-complete while Strong rainbow connectivity is in P. We conclude by considering some tractable special cases, and show for instance that both problems are in XP when parameterized by tree-depth. AB - A path in an edge-colored graph is rainbow if no two edges of it are colored the same. The graph is said to be rainbow connected if there is a rainbow path between every pair of vertices. If there is a rainbow shortest path between every pair of vertices, the graph is strong rainbow connected. We consider the complexity of the problem of deciding if a given edge-colored graph is rainbow or strong rainbow connected. These problems are called Rainbow connectivity and Strong rainbow connectivity, respectively. We prove both problems remain NP-complete on interval outerplanar graphs and k-regular graphs for k≥3. Previously, no graph class was known where the complexity of the two problems would differ. We show that for block graphs, which form a subclass of chordal graphs, Rainbow connectivity is NP-complete while Strong rainbow connectivity is in P. We conclude by considering some tractable special cases, and show for instance that both problems are in XP when parameterized by tree-depth. KW - Computational complexity KW - Rainbow connectivity U2 - 10.1016/j.dam.2015.07.041 DO - 10.1016/j.dam.2015.07.041 M3 - Article VL - 201 SP - 191 EP - 200 JO - Discrete Applied Mathematics JF - Discrete Applied Mathematics SN - 0166-218X ER - TY - JOUR T1 - Gaussian filtering and variational approximations for Bayesian smoothing in continuous-discrete stochastic dynamic systems AU - Ala-Luhtala, Juha AU - Särkkä, Simo AU - Piche, Robert N1 - Available online 19 Dec,2014, preprint http://arxiv.org/abs/1407.5874 (vol 111, June2015, s. 124-136)

Contribution: organisation=ase,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Portfolio EDEND: 2015-01-09

Publisher name: Elsevier

publication_forum:67104 PY - 2015/6 Y1 - 2015/6 N2 - The Bayesian smoothing equations are generally intractable for systems described by nonlinear stochastic differential equations and discrete-time measurements. Gaussian approximations are a computationally efficient way to approximate the true smoothing distribution. In this work, we present a comparison between two Gaussian approximation methods. The Gaussian filtering based Gaussian smoother uses a Gaussian approximation for the filtering distribution to form an approximation for the smoothing distribution. The variational Gaussian smoother is based on minimizing the Kullback-Leibler divergence of the approximate smoothing distribution with respect to the true distribution. The results suggest that for highly nonlinear systems, the variational Gaussian smoother can be used to iteratively improve the Gaussian filtering based smoothing solution. We also present linearization and sigma-point methods to approximate the intractable Gaussian expectations in the variational Gaussian smoothing equations. In addition, we extend the variational Gaussian smoother for certain class of systems with singular diffusion matrix. AB - The Bayesian smoothing equations are generally intractable for systems described by nonlinear stochastic differential equations and discrete-time measurements. Gaussian approximations are a computationally efficient way to approximate the true smoothing distribution. In this work, we present a comparison between two Gaussian approximation methods. The Gaussian filtering based Gaussian smoother uses a Gaussian approximation for the filtering distribution to form an approximation for the smoothing distribution. The variational Gaussian smoother is based on minimizing the Kullback-Leibler divergence of the approximate smoothing distribution with respect to the true distribution. The results suggest that for highly nonlinear systems, the variational Gaussian smoother can be used to iteratively improve the Gaussian filtering based smoothing solution. We also present linearization and sigma-point methods to approximate the intractable Gaussian expectations in the variational Gaussian smoothing equations. In addition, we extend the variational Gaussian smoother for certain class of systems with singular diffusion matrix. U2 - 10.1016/j.sigpro.2014.12.013 DO - 10.1016/j.sigpro.2014.12.013 M3 - Article VL - 111 SP - 124 EP - 136 JO - Signal Processing JF - Signal Processing SN - 0165-1684 ER - TY - JOUR T1 - Gaussian Process Regression for Forest Attribute Estimation From Airborne Laser Scanning Data AU - Varvia, Petri AU - Lähivaara, Timo AU - Maltamo, Matti AU - Packalen, Petteri AU - Seppänen, Aku PY - 2019/6 Y1 - 2019/6 N2 - While the analysis of airborne laser scanning (ALS) data often provides reliable estimates for certain forest stand attributes-such as total volume or basal area-there is still room for improvement, especially in estimating species-specific attributes. Moreover, while the information on the estimate uncertainty would be useful in various economic and environmental analyses on forests, a computationally feasible framework for uncertainty quantifying in ALS is still missing. In this paper, the species-specific stand attribute estimation and uncertainty quantification (UQ) is approached using Gaussian process regression (GPR), which is a nonlinear and nonparametric machine learning method. Multiple species-specific stand attributes are estimated simultaneously: tree height, stem diameter, stem number, basal area, and stem volume. The cross-validation results show that GPR yields on average an improvement of 4.6% in estimate root mean square error over a state-of-the-art k-nearest neighbors (kNNs) implementation, negligible bias and well performing UQ (credible intervals), while being computationally fast. The performance advantage over kNN and the feasibility of credible intervals persists even when smaller training sets are used. AB - While the analysis of airborne laser scanning (ALS) data often provides reliable estimates for certain forest stand attributes-such as total volume or basal area-there is still room for improvement, especially in estimating species-specific attributes. Moreover, while the information on the estimate uncertainty would be useful in various economic and environmental analyses on forests, a computationally feasible framework for uncertainty quantifying in ALS is still missing. In this paper, the species-specific stand attribute estimation and uncertainty quantification (UQ) is approached using Gaussian process regression (GPR), which is a nonlinear and nonparametric machine learning method. Multiple species-specific stand attributes are estimated simultaneously: tree height, stem diameter, stem number, basal area, and stem volume. The cross-validation results show that GPR yields on average an improvement of 4.6% in estimate root mean square error over a state-of-the-art k-nearest neighbors (kNNs) implementation, negligible bias and well performing UQ (credible intervals), while being computationally fast. The performance advantage over kNN and the feasibility of credible intervals persists even when smaller training sets are used. KW - Area-based approach (ABA) KW - forest inventory KW - Gaussian process (GP) KW - light detection and ranging (LiDAR) KW - machine learning. U2 - 10.1109/TGRS.2018.2883495 DO - 10.1109/TGRS.2018.2883495 M3 - Article VL - 57 SP - 3361 EP - 3369 JO - IEEE Transactions on Geoscience and Remote Sensing JF - IEEE Transactions on Geoscience and Remote Sensing SN - 0196-2892 IS - 6 ER - TY - JOUR T1 - Gaussian Scale Mixture Models For Robust Linear Multivariate Regression With Missing Data AU - Ala-Luhtala, Juha AU - Piche, Robert N1 - Online first.Accepted author version posted online 19 Jun 2014

Contribution: organisation=mat,FACT1=0.25

Contribution: organisation=ase,FACT2=0.75

Portfolio EDEND: 2014-11-25

Publisher name: Taylor & Francis PY - 2014 Y1 - 2014 N2 - We present an algorithm for multivariate robust Bayesian linear regression with missing data. The iterative algorithm computes an approximative posterior for the model parameters based on the variational Bayes (VB) method. Compared to the EM algorithm, the VB method has the advantage that the variance for the model parameters is also computed directly by the algorithm. We consider three families of Gaussian scale mixture models for the measurements, which include as special cases the multivariate t distribution, the multivariate Laplace distribution, and the contaminated normal model. The observations can contain missing values, assuming that the missing data mechanism can be ignored. A Matlab/Octave implementation of the algorithm is presented and applied to solve threereference examples from the literature. AB - We present an algorithm for multivariate robust Bayesian linear regression with missing data. The iterative algorithm computes an approximative posterior for the model parameters based on the variational Bayes (VB) method. Compared to the EM algorithm, the VB method has the advantage that the variance for the model parameters is also computed directly by the algorithm. We consider three families of Gaussian scale mixture models for the measurements, which include as special cases the multivariate t distribution, the multivariate Laplace distribution, and the contaminated normal model. The observations can contain missing values, assuming that the missing data mechanism can be ignored. A Matlab/Octave implementation of the algorithm is presented and applied to solve threereference examples from the literature. U2 - 10.1080/03610918.2013.875565 DO - 10.1080/03610918.2013.875565 M3 - Article JO - Communications in Statistics: Simulation and Computation JF - Communications in Statistics: Simulation and Computation SN - 0361-0918 ER - TY - JOUR T1 - General Integral Formulas for k-hyper-mono-genic Functions AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki PY - 2017 Y1 - 2017 N2 - We are studying a function theory of k-hypermonogenic functions connected to k-hyperbolic harmonic functions that are harmonic with respect to the hyperbolic Riemannian metric k2=xn2k1-n(dx02+⋯+dxn2)in the upper half space R+n+1={(x0,…,xn)|xi∈R,xn>0}. The function theory based on this metric is important, since in case k= n- 1 , the metric is the hyperbolic metric of the Poincaré upper half space and Leutwiler noticed that the power function xm(m∈N0), calculated using Clifford algebras, is a conjugate gradient of a hyperbolic harmonic function. We find a fundamental k-hyperbolic harmonic function. Using this function we are able to find kernels and integral formulas for k-hypermonogenic functions. Earlier these results have been verified for hypermonogenic functions (k= n- 1) and for k-hyperbolic harmonic functions in odd dimensional spaces. AB - We are studying a function theory of k-hypermonogenic functions connected to k-hyperbolic harmonic functions that are harmonic with respect to the hyperbolic Riemannian metric k2=xn2k1-n(dx02+⋯+dxn2)in the upper half space R+n+1={(x0,…,xn)|xi∈R,xn>0}. The function theory based on this metric is important, since in case k= n- 1 , the metric is the hyperbolic metric of the Poincaré upper half space and Leutwiler noticed that the power function xm(m∈N0), calculated using Clifford algebras, is a conjugate gradient of a hyperbolic harmonic function. We find a fundamental k-hyperbolic harmonic function. Using this function we are able to find kernels and integral formulas for k-hypermonogenic functions. Earlier these results have been verified for hypermonogenic functions (k= n- 1) and for k-hyperbolic harmonic functions in odd dimensional spaces. U2 - 10.1007/s00006-015-0629-7 DO - 10.1007/s00006-015-0629-7 M3 - Article VL - 27 SP - 99 EP - 110 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 1 ER - TY - JOUR T1 - Graph entropy based on the number of spanning forests of c-cyclic graphs AU - Wan, Pengfei AU - Tu, Jianhua AU - Dehmer, Matthias AU - Zhang, Shenggui AU - Emmert-Streib, Frank PY - 2019/12/15 Y1 - 2019/12/15 N2 - Graph entropies have been introduced to quantitatively measure the structural information content of graphs and networks; they have plenty of applications in various fields. Utilizing the number of subgraphs to establish measures for determining the complexity of molecular graphs are also prevalent in the study of mathematical chemistry. In this paper, we develop a new graph entropy measure that is based on the number of spanning forests. We prove explicit expressions for the entropy for trees, unicyclic and bicyclic graphs, and show that the cycle graph Cn attains the maximal value of the entropy for unicyclic graphs with order n and large cycle lengths. Based on generating numerical results, we conjecture extremal unicyclic graphs with respect to the entropy as well as we compare the values of our entropy for c-cyclic graphs, and generate graphs of bicyclic graphs and tricyclic graphs with 6 vertices for performing further research. AB - Graph entropies have been introduced to quantitatively measure the structural information content of graphs and networks; they have plenty of applications in various fields. Utilizing the number of subgraphs to establish measures for determining the complexity of molecular graphs are also prevalent in the study of mathematical chemistry. In this paper, we develop a new graph entropy measure that is based on the number of spanning forests. We prove explicit expressions for the entropy for trees, unicyclic and bicyclic graphs, and show that the cycle graph Cn attains the maximal value of the entropy for unicyclic graphs with order n and large cycle lengths. Based on generating numerical results, we conjecture extremal unicyclic graphs with respect to the entropy as well as we compare the values of our entropy for c-cyclic graphs, and generate graphs of bicyclic graphs and tricyclic graphs with 6 vertices for performing further research. KW - Graph entropy KW - Spanning forest KW - Subgraph U2 - 10.1016/j.amc.2019.124616 DO - 10.1016/j.amc.2019.124616 M3 - Article VL - 363 JO - Applied Mathematics and Computation JF - Applied Mathematics and Computation SN - 0096-3003 M1 - 124616 ER - TY - JOUR T1 - Gravitational scattering by giant planets AU - Laakso, T. AU - Rantala, J. AU - Kaasalainen, M. N1 - Contribution: organisation=mat,FACT1=1 PY - 2006 Y1 - 2006 U2 - 10.1051/0004-6361:20065121 DO - 10.1051/0004-6361:20065121 M3 - Article VL - 456 SP - 373 EP - 378 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 ER - TY - JOUR T1 - Guard-based Partial Order Reduction AU - Laarman, Alfons AU - Pater, Elwin AU - Van de Pol, Jaco AU - Hansen, Henri PY - 2014/12 Y1 - 2014/12 N2 - This paper aims at making partial-order reduction independent of the modeling language. To this end, we present a guard-based method which is a general-purpose implementation of the stubborn set method. We approach the implementation through so-called necessary enabling sets and do-not-accord sets, and give an algorithm suitable for an abstract model checking interface. We also introduce necessary disabling sets and heuristics to produce smaller stubborn sets and thus better reduction at low costs. We explore the effect of these methods using an implementation in the model checker LTSmin. We experiment with partial-order reduction on a number of Promela models, on benchmarks from the BEEM database in the DVE language, and with several with LTL properties. The efficiency of the heuristic algorithm is established by a comparison to the subset-minimal Deletion algorithm and the simple closure algorithm. We also compare our results to the Spin model checker. While the reductions take longer, they are consistently better than Spin ’s ample set and often surpass the upper bound for the process-based ample sets, established empirically earlier on BEEM models. AB - This paper aims at making partial-order reduction independent of the modeling language. To this end, we present a guard-based method which is a general-purpose implementation of the stubborn set method. We approach the implementation through so-called necessary enabling sets and do-not-accord sets, and give an algorithm suitable for an abstract model checking interface. We also introduce necessary disabling sets and heuristics to produce smaller stubborn sets and thus better reduction at low costs. We explore the effect of these methods using an implementation in the model checker LTSmin. We experiment with partial-order reduction on a number of Promela models, on benchmarks from the BEEM database in the DVE language, and with several with LTL properties. The efficiency of the heuristic algorithm is established by a comparison to the subset-minimal Deletion algorithm and the simple closure algorithm. We also compare our results to the Spin model checker. While the reductions take longer, they are consistently better than Spin ’s ample set and often surpass the upper bound for the process-based ample sets, established empirically earlier on BEEM models. U2 - 10.1007/s10009-014-0363-9 DO - 10.1007/s10009-014-0363-9 M3 - Article VL - 18 SP - 427 EP - 448 JO - International Journal on Software Tools for Technology Transfer JF - International Journal on Software Tools for Technology Transfer SN - 1433-2779 IS - 4 ER - TY - JOUR T1 - Harmonic Forms on Conformal Euclidean Manifolds: The Clifford Multivector Approach AU - Orelma, Heikki N1 - Online first, Springer

Contribution: organisation=mat,FACT1=1 PY - 2012 Y1 - 2012 U2 - 10.1007/s00006-011-0297-1 DO - 10.1007/s00006-011-0297-1 M3 - Article VL - 22 SP - 143 EP - 158 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 1 ER - TY - JOUR T1 - Hierarchical Bayesian inference for the EEG inverse problem using realistic FE head models: Depth localization and source separation for focal primary currents AU - Lucka, Felix AU - Pursiainen, Sampsa AU - Burger, Martin AU - Wolters, Carsten H. N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Elsevier PY - 2012 Y1 - 2012 U2 - 10.1016/j.neuroimage.2012.04.017 DO - 10.1016/j.neuroimage.2012.04.017 M3 - Article VL - 61 SP - 1364 EP - 1382 JO - NeuroImage JF - NeuroImage SN - 1053-8119 IS - 4 ER - TY - JOUR T1 - Homogeneous internal structure of CM-like asteroid (41) Daphne AU - Carry, B. AU - Vachier, F. AU - Berthier, J. AU - Marsset, M. AU - Vernazza, P. AU - Grice, J. AU - Merline, W. J. AU - Lagadec, E. AU - Fienga, A. AU - Conrad, A. AU - Podlewska-Gaca, E. AU - Santana-Ros, T. AU - Viikinkoski, M. AU - Hanuš, J. AU - Dumas, C. AU - Drummond, J. D. AU - Tamblyn, P. M. AU - Chapman, C. R. AU - Behrend, R. AU - Bernasconi, L. AU - Bartczak, P. AU - Benkhaldoun, Z. AU - Birlan, M. AU - Castillo-Rogez, J. AU - Cipriani, F. AU - Colas, F. AU - Drouard, A. AU - Durech, J. AU - Enke, B. L. AU - Fauvaud, S. AU - Ferrais, M. AU - Fetick, R. AU - Fusco, T. AU - Gillon, M. AU - Jehin, E. AU - Jorda, L. AU - Kaasalainen, M. AU - Keppler, M. AU - Kryszczynska, A. AU - Lamy, P. AU - Marchis, F. AU - Marciniak, A. AU - Michalowski, T. AU - Michel, P. AU - Pajuelo, M. AU - Tanga, P. AU - Vigan, A. AU - Warner, B. AU - Witasse, O. AU - Yang, B. AU - Zurlo, A. PY - 2019/3/1 Y1 - 2019/3/1 N2 - Context. CM-like asteroids (Ch and Cgh classes) are a major population within the broader C-complex, encompassing about 10% of the mass of the main asteroid belt. Their internal structure has been predicted to be homogeneous, based on their compositional similarity as inferred from spectroscopy and numerical modeling of their early thermal evolution. Aims. Here we aim to test this hypothesis by deriving the density of the CM-like asteroid (41) Daphne from detailed modeling of its shape and the orbit of its small satellite. Methods. We observed Daphne and its satellite within our imaging survey with the Very Large Telescope extreme adaptive-optics SPHERE/ZIMPOL camera and complemented this data set with earlier Keck/NIRC2 and VLT/NACO observations. We analyzed the dynamics of the satellite with our Genoid meta-heuristic algorithm. Combining our high-angular resolution images with optical lightcurves and stellar occultations, we determine the spin period, orientation, and 3D shape, using our ADAM shape modeling algorithm. Results. The satellite orbits Daphne on an equatorial, quasi-circular, prograde orbit, like the satellites of many other large main-belt asteroids. The shape model of Daphne reveals several large flat areas that could be large impact craters. The mass determined from this orbit combined with the volume computed from the shape model implies a density for Daphne of 1.77 ± 0.26 g cm -3 (3 σ). This densityis consistent with a primordial CM-like homogeneous internal structure with some level of macroporosity (≈ 17%). Conclusions. Based on our analysis of the density of Daphne and 75 other Ch/Cgh-type asteroids gathered from the literature, we conclude that the primordial internal structure of the CM parent bodies was homogeneous. AB - Context. CM-like asteroids (Ch and Cgh classes) are a major population within the broader C-complex, encompassing about 10% of the mass of the main asteroid belt. Their internal structure has been predicted to be homogeneous, based on their compositional similarity as inferred from spectroscopy and numerical modeling of their early thermal evolution. Aims. Here we aim to test this hypothesis by deriving the density of the CM-like asteroid (41) Daphne from detailed modeling of its shape and the orbit of its small satellite. Methods. We observed Daphne and its satellite within our imaging survey with the Very Large Telescope extreme adaptive-optics SPHERE/ZIMPOL camera and complemented this data set with earlier Keck/NIRC2 and VLT/NACO observations. We analyzed the dynamics of the satellite with our Genoid meta-heuristic algorithm. Combining our high-angular resolution images with optical lightcurves and stellar occultations, we determine the spin period, orientation, and 3D shape, using our ADAM shape modeling algorithm. Results. The satellite orbits Daphne on an equatorial, quasi-circular, prograde orbit, like the satellites of many other large main-belt asteroids. The shape model of Daphne reveals several large flat areas that could be large impact craters. The mass determined from this orbit combined with the volume computed from the shape model implies a density for Daphne of 1.77 ± 0.26 g cm -3 (3 σ). This densityis consistent with a primordial CM-like homogeneous internal structure with some level of macroporosity (≈ 17%). Conclusions. Based on our analysis of the density of Daphne and 75 other Ch/Cgh-type asteroids gathered from the literature, we conclude that the primordial internal structure of the CM parent bodies was homogeneous. KW - asteroids: general KW - Methods: observational KW - Minor planets KW - Minor planets, asteroids: individual: Daphne KW - Techniques: high angular resolution U2 - 10.1051/0004-6361/201833898 DO - 10.1051/0004-6361/201833898 M3 - Article VL - 623 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A132 ER - TY - JOUR T1 - Hosoya entropy of fullerene graphs AU - Ghorbani, Modjtaba AU - Dehmer, Matthias AU - Rajabi-Parsa, Mina AU - Emmert-Streib, Frank AU - Mowshowitz, Abbe PY - 2019/7/1 Y1 - 2019/7/1 N2 - Entropy-based methods are useful tools for investigating various problems in mathematical chemistry, computational physics and pattern recognition. In this paper we introduce a general framework for applying Shannon entropy to fullerene graphs, and used it to investigate their properties. We show that important physical properties of these molecules can be determined by applying Hosoya entropy to their corresponding graphs. AB - Entropy-based methods are useful tools for investigating various problems in mathematical chemistry, computational physics and pattern recognition. In this paper we introduce a general framework for applying Shannon entropy to fullerene graphs, and used it to investigate their properties. We show that important physical properties of these molecules can be determined by applying Hosoya entropy to their corresponding graphs. KW - Graph entropy KW - Graph automorphism KW - Fullerene graphs U2 - 10.1016/j.amc.2019.01.024 DO - 10.1016/j.amc.2019.01.024 M3 - Article VL - 352 SP - 88 EP - 98 JO - Applied Mathematics and Computation JF - Applied Mathematics and Computation SN - 0096-3003 ER - TY - JOUR T1 - How management intensity and neighborhood composition affect the structure of beech (Fagus sylvatica L.) trees AU - Juchheim, Julia AU - Annighöfer, Peter AU - Ammer, Christian AU - Calders, Kim AU - Raumonen, Pasi AU - Seidel, Dominik PY - 2017/7/14 Y1 - 2017/7/14 N2 - Key message: The intensity of silvicultural interventions and the neighborhood composition determine branching patterns, crown shape, and trunk attributes of beech (Fagus sylvaticaL.) trees.Abstract: The intensity of silvicultural interventions and the composition of tree species are important forest management decisions. Both determine tree shape and thus influence the value of a tree, be it in terms of economy (trunk form, branchiness), or in terms of ecology (microhabitats). However, our knowledge on the distinct changes in tree architecture due to silvicultural management intensity or different neighborhood diversities is still limited, especially if the focus is on single tree attributes, e.g., branching patterns or crown shapes. We used terrestrial laser scanner data to calculate 25 structural measures for 55 European beech (Fagus sylvatica L.) trees that grew either in pure stands along a gradient of management intensity or in intra or interspecific neighborhoods in unmanaged stands. We found a lower height of maximal horizontal crown extension, a higher crown surface area, and straighter trunks with increasing management intensity. Moreover, our study revealed that beech trees surrounded by valuable hardwoods showed a lower height of maximal horizontal crown extension, a lower height–diameter ratio, and longer branches with flatter branch angles than beech trees surrounded by conspecific neighbors. Our findings provide evidence of phenotypic plasticity of European beech to diverse environmental conditions. The differences in tree structure indicate an increasing crown competition with decreasing management intensity and stronger competitive pressure for beech surrounded by conspecific neighbors in comparison to alien neighbors. AB - Key message: The intensity of silvicultural interventions and the neighborhood composition determine branching patterns, crown shape, and trunk attributes of beech (Fagus sylvaticaL.) trees.Abstract: The intensity of silvicultural interventions and the composition of tree species are important forest management decisions. Both determine tree shape and thus influence the value of a tree, be it in terms of economy (trunk form, branchiness), or in terms of ecology (microhabitats). However, our knowledge on the distinct changes in tree architecture due to silvicultural management intensity or different neighborhood diversities is still limited, especially if the focus is on single tree attributes, e.g., branching patterns or crown shapes. We used terrestrial laser scanner data to calculate 25 structural measures for 55 European beech (Fagus sylvatica L.) trees that grew either in pure stands along a gradient of management intensity or in intra or interspecific neighborhoods in unmanaged stands. We found a lower height of maximal horizontal crown extension, a higher crown surface area, and straighter trunks with increasing management intensity. Moreover, our study revealed that beech trees surrounded by valuable hardwoods showed a lower height of maximal horizontal crown extension, a lower height–diameter ratio, and longer branches with flatter branch angles than beech trees surrounded by conspecific neighbors. Our findings provide evidence of phenotypic plasticity of European beech to diverse environmental conditions. The differences in tree structure indicate an increasing crown competition with decreasing management intensity and stronger competitive pressure for beech surrounded by conspecific neighbors in comparison to alien neighbors. KW - Competition KW - Crown plasticity KW - Quantitative structural models KW - Terrestrial laser scanning KW - Thinning KW - Tree architecture U2 - 10.1007/s00468-017-1581-z DO - 10.1007/s00468-017-1581-z M3 - Article VL - 31 SP - 1723 EP - 1735 JO - TREES-STRUCTURE AND FUNCTION JF - TREES-STRUCTURE AND FUNCTION SN - 0931-1890 IS - 5 ER - TY - JOUR T1 - Hubble Space Telescope observations of the nucleus and inner coma of comet 67P AU - Lamy, P.L. AU - Toth, I. AU - Weaver, H.A. AU - Jorda, L. AU - Kaasalainen, M. AU - Gutierrez, P. N1 - Contribution: organisation=mat,FACT1=1 PY - 2006 Y1 - 2006 U2 - 10.1051/0004-6361:20065253 DO - 10.1051/0004-6361:20065253 M3 - Article VL - 458 SP - 669 EP - 678 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 ER - TY - JOUR T1 - Hyperbolic extensions of integral formulas AU - Eriksson, Sirkka-Liisa N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1007/s00006-010-0211-2 DO - 10.1007/s00006-010-0211-2 M3 - Article VL - 20 SP - 575 EP - 586 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 3-4 ER - TY - JOUR T1 - Hyperbolic Function Theory in the Skew-Field of Quaternions AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - EXT="Eriksson, Sirkka-Liisa" PY - 2019/11/1 Y1 - 2019/11/1 N2 - We are studying hyperbolic function theory in the total skew-field of quaternions. Earlier the theory has been studied for quaternion valued functions depending only on three reduced variables. Our functions are depending on all four coordinates of quaternions. We consider functions, called α-hyperbolic harmonic, that are harmonic with respect to the Riemannian metric dsα2=dx02+dx12+dx22+dx32x3αin the upper half space R+4={(x0,x1,x2,x3)∈R4:x3>0}. If α= 2 , the metric is the hyperbolic metric of the Poincaré upper half-space. Hempfling and Leutwiler started to study this case and noticed that the quaternionic power function xm(m∈Z), is a conjugate gradient of a 2-hyperbolic harmonic function. They researched polynomial solutions. Using fundamental α-hyperbolic harmonic functions, depending only on the hyperbolic distance and x3, we verify a Cauchy type integral formula for conjugate gradient of α-hyperbolic harmonic functions. We also compare these results with the properties of paravector valued α-hypermonogenic in the Clifford algebra Cℓ0,3. AB - We are studying hyperbolic function theory in the total skew-field of quaternions. Earlier the theory has been studied for quaternion valued functions depending only on three reduced variables. Our functions are depending on all four coordinates of quaternions. We consider functions, called α-hyperbolic harmonic, that are harmonic with respect to the Riemannian metric dsα2=dx02+dx12+dx22+dx32x3αin the upper half space R+4={(x0,x1,x2,x3)∈R4:x3>0}. If α= 2 , the metric is the hyperbolic metric of the Poincaré upper half-space. Hempfling and Leutwiler started to study this case and noticed that the quaternionic power function xm(m∈Z), is a conjugate gradient of a 2-hyperbolic harmonic function. They researched polynomial solutions. Using fundamental α-hyperbolic harmonic functions, depending only on the hyperbolic distance and x3, we verify a Cauchy type integral formula for conjugate gradient of α-hyperbolic harmonic functions. We also compare these results with the properties of paravector valued α-hypermonogenic in the Clifford algebra Cℓ0,3. KW - Clifford algebra KW - Hyperbolic Laplace operator KW - Hyperbolic metric KW - Laplace–Beltrami operator KW - Monogenic function KW - Quaternions KW - α-hyperbolic harmonic KW - α-hypermonogenic U2 - 10.1007/s00006-019-1017-5 DO - 10.1007/s00006-019-1017-5 M3 - Article VL - 29 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 5 M1 - 97 ER - TY - JOUR T1 - Hyperbolic Laplace Operator and the Weinstein Equation in R^3 AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - Online first; Published online: 22 October 2013

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-11-29

Publisher name: Springer PY - 2013 Y1 - 2013 U2 - 10.1007/s00006-013-0425-1 DO - 10.1007/s00006-013-0425-1 M3 - Article SP - 1 EP - 16 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 ER - TY - JOUR T1 - Hypermonogenic Plane Wave Solutions of the Dirac Equation in Superspace AU - Adán, Alí Guzmán AU - Orelma, Heikki AU - Sommen, Frank PY - 2019/9/1 Y1 - 2019/9/1 N2 - In this paper, we obtain Cauchy–Kovalevskaya theorems for hypermonogenic superfunctions depending only on purely bosonic and fermionic vector variables. In addition, we use these results to construct plane wave examples of such functions. AB - In this paper, we obtain Cauchy–Kovalevskaya theorems for hypermonogenic superfunctions depending only on purely bosonic and fermionic vector variables. In addition, we use these results to construct plane wave examples of such functions. KW - Cauchy–Kovalevskaya extension KW - Clifford analysis KW - Hypermonogenic functions KW - Plane waves KW - Superspace U2 - 10.1007/s00006-019-0981-0 DO - 10.1007/s00006-019-0981-0 M3 - Article VL - 29 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 4 M1 - 71 ER - TY - JOUR T1 - If a student takes control: facilitators' tasks and responsibilities AU - Väljataga, T. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 U2 - 10.1007/978-3-642-03426-8_47 DO - 10.1007/978-3-642-03426-8_47 M3 - Article VL - 5686 SP - 390 EP - 399 JO - Lecture Notes in Computer Science JF - Lecture Notes in Computer Science SN - 0302-9743 ER - TY - JOUR T1 - Images of asteroid 21 Lutetia: A remnant planetesimal from the early solar system AU - Sierks, H. AU - Lamy, P. AU - Barbieri, C. AU - Koschny, D. AU - Rickman, H. AU - Rodrigo, R. AU - A'Hearn, M.F. AU - Angrilli, F. AU - Barucci, M.A. AU - Bertaux, J.-L. AU - Bertini, I. AU - Besse, S. AU - Carry, B. AU - Cremonese, G. AU - Da Deppo, V. AU - Davidsson, B. AU - Debei, S. AU - De Cecco, M. AU - De Leon, J. AU - Ferri, F. AU - Fornasier, S. AU - Fulle, M. AU - Hviid, S.F. AU - Gaskell, R.W. AU - Groussin, O. AU - Gutierrez, P. AU - Ip, W. AU - Jorda, L. AU - Kaasalainen, M. AU - Keller, H.U. AU - Knollenberg, J. AU - Kramm, R. AU - Kührt, E. AU - Küppers, M. AU - Lara, L. AU - Lazzarin, M. AU - Leyrat, C. AU - Lopez Moreno, J.J. AU - Magrin, S. AU - Marchi, S. AU - Marzari, F. AU - Massironi, M. AU - Michalik, H. AU - Moissl, R. AU - Naletto, G. AU - Preusker, F. AU - Sabau, L. AU - Sabolo, W. AU - Scholten, F. AU - Snodgrass, C. AU - Thomas, N. AU - Tubiana, C. AU - Vernazza, P. AU - Vincent, J.-B. AU - Wenzel, K.-P. AU - Andert, T. AU - Pätzold, M. AU - Weiss, B.P N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1126/science.1207325 DO - 10.1126/science.1207325 M3 - Article VL - 334 SP - 487 EP - 490 JO - Science JF - Science SN - 0036-8075 IS - 6055 ER - TY - JOUR T1 - Improved EEG source localization with Bayesian uncertainty modelling of unknown skull conductivity AU - Rimpiläinen, Ville AU - Koulouri, Alexandra AU - Lucka, Felix AU - Kaipio, Jari P. AU - Wolters, Carsten H. N1 - EXT="Rimpiläinen, Ville" PY - 2019/3/1 Y1 - 2019/3/1 N2 - Electroencephalography (EEG) source imaging is an ill-posed inverse problem that requires accurate conductivity modelling of the head tissues, especially the skull. Unfortunately, the conductivity values are difficult to determine in vivo. In this paper, we show that the exact knowledge of the skull conductivity is not always necessary when the Bayesian approximation error (BAE) approach is exploited. In BAE, we first postulate a probability distribution for the skull conductivity that describes our (lack of) knowledge on its value, and model the effects of this uncertainty on EEG recordings with the help of an additive error term in the observation model. Before the Bayesian inference, the likelihood is marginalized over this error term. Thus, in the inversion we estimate only our primary unknown, the source distribution. We quantified the improvements in the source localization when the proposed Bayesian modelling was used in the presence of different skull conductivity errors and levels of measurement noise. Based on the results, BAE was able to improve the source localization accuracy, particularly when the unknown (true) skull conductivity was much lower than the expected standard conductivity value. The source locations that gained the highest improvements were shallow and originally exhibited the largest localization errors. In our case study, the benefits of BAE became negligible when the signal-to-noise ratio dropped to 20 dB. AB - Electroencephalography (EEG) source imaging is an ill-posed inverse problem that requires accurate conductivity modelling of the head tissues, especially the skull. Unfortunately, the conductivity values are difficult to determine in vivo. In this paper, we show that the exact knowledge of the skull conductivity is not always necessary when the Bayesian approximation error (BAE) approach is exploited. In BAE, we first postulate a probability distribution for the skull conductivity that describes our (lack of) knowledge on its value, and model the effects of this uncertainty on EEG recordings with the help of an additive error term in the observation model. Before the Bayesian inference, the likelihood is marginalized over this error term. Thus, in the inversion we estimate only our primary unknown, the source distribution. We quantified the improvements in the source localization when the proposed Bayesian modelling was used in the presence of different skull conductivity errors and levels of measurement noise. Based on the results, BAE was able to improve the source localization accuracy, particularly when the unknown (true) skull conductivity was much lower than the expected standard conductivity value. The source locations that gained the highest improvements were shallow and originally exhibited the largest localization errors. In our case study, the benefits of BAE became negligible when the signal-to-noise ratio dropped to 20 dB. KW - Bayesian inverse problem KW - Electroencephalography KW - Skull conductivity KW - Source localization KW - Uncertainty modelling U2 - 10.1016/j.neuroimage.2018.11.058 DO - 10.1016/j.neuroimage.2018.11.058 M3 - Article VL - 188 SP - 252 EP - 260 JO - NeuroImage JF - NeuroImage SN - 1053-8119 ER - TY - JOUR T1 - Indirect Emissions of Forest Bioenergy: Detailed Modelling of Stump-Root Systems AU - Liski, Jari AU - Kaasalainen, Sanna AU - Raumonen, Pasi AU - Akujärvi, Anu AU - Krooks, Anssi AU - Repo, Anna AU - Kaasalainen, Mikko N1 - Article first published online: 26 MAY 2013

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-07-29

Publisher name: Wiley-Blackwell PY - 2014 Y1 - 2014 U2 - 10.1111/gcbb.12091 DO - 10.1111/gcbb.12091 M3 - Article VL - 6 SP - 777 EP - 784 JO - Global Change Biology Bioenergy JF - Global Change Biology Bioenergy SN - 1757-1693 IS - 6 ER - TY - JOUR T1 - Information Diversity in Structure and Dynamics of Simulated Neuronal Networks AU - Mäki-Marttunen, Tuomo AU - Acimovic, Jugoslava AU - Nykter, Matti AU - Kesseli, Juha AU - Ruohonen, Keijo AU - Yli-Harja, Olli AU - Linne, Marja-Leena N1 - Ei UT-numeroa 5.4.2014

Contribution: organisation=sgn,FACT1=0.7

Contribution: organisation=mat,FACT2=0.3 PY - 2011 Y1 - 2011 N2 - Neuronal networks exhibit a wide diversity of structures, which contributes to the diversity of the dynamics therein. The presented work applies an information theoretic framework to simultaneously analyze structure and dynamics in neuronal networks. Information diversity within the structure and dynamics of a neuronal network is studied using the normalized compression distance. To describe the structure, a scheme for generating distance-dependent networks with identical in-degree distribution but variable strength of dependence on distance is presented. The resulting network structure classes possess differing path length and clustering coefficient distributions. In parallel, comparable realistic neuronal networks are generated with NETMORPH simulator and similar analysis is done on them. To describe the dynamics, network spike trains are simulated using different network structures and their bursting behaviors are analyzed. For the simulation of the network activity the Izhikevich model of spiking neurons is used together with the Tsodyks model of dynamical synapses. We show that the structure of the simulated neuronal networks affects the spontaneous bursting activity when measured with bursting frequency and a set of intraburst measures: the more locally connected produce more and longer bursts than the more random networks. The information diversity of the structure of a network is greatest in the most locally connected, smallest in random networks, and somewhere in between in the networks between order and disorder. As for the dynamics, the most locally connected and some of the in-between networks produce the most complex intraburst spike trains. The same result also holds for sparser of the two considered network densities in the case of full spike trains. AB - Neuronal networks exhibit a wide diversity of structures, which contributes to the diversity of the dynamics therein. The presented work applies an information theoretic framework to simultaneously analyze structure and dynamics in neuronal networks. Information diversity within the structure and dynamics of a neuronal network is studied using the normalized compression distance. To describe the structure, a scheme for generating distance-dependent networks with identical in-degree distribution but variable strength of dependence on distance is presented. The resulting network structure classes possess differing path length and clustering coefficient distributions. In parallel, comparable realistic neuronal networks are generated with NETMORPH simulator and similar analysis is done on them. To describe the dynamics, network spike trains are simulated using different network structures and their bursting behaviors are analyzed. For the simulation of the network activity the Izhikevich model of spiking neurons is used together with the Tsodyks model of dynamical synapses. We show that the structure of the simulated neuronal networks affects the spontaneous bursting activity when measured with bursting frequency and a set of intraburst measures: the more locally connected produce more and longer bursts than the more random networks. The information diversity of the structure of a network is greatest in the most locally connected, smallest in random networks, and somewhere in between in the networks between order and disorder. As for the dynamics, the most locally connected and some of the in-between networks produce the most complex intraburst spike trains. The same result also holds for sparser of the two considered network densities in the case of full spike trains. U2 - 10.3389/fncom.2011.00026 DO - 10.3389/fncom.2011.00026 M3 - Article VL - 5 SP - 1 EP - 17 JO - Frontiers in Computational Neuroscience JF - Frontiers in Computational Neuroscience SN - 1662-5188 M1 - 26 ER - TY - JOUR T1 - Integral kernels for k-hypermonogenic functions AU - Vuojamo, Vesa AU - Eriksson, Sirkka-Liisa N1 - EXT="Eriksson, Sirkka-Liisa" PY - 2017 Y1 - 2017 N2 - We consider the modified Cauchy–Riemann operator (Formula presented.) in the universal Clifford algebra (Formula presented.) with the basis (Formula presented.). The null-solutions of this operator are called k-hypermonogenic functions. We calculate the k-hyperbolic harmonic fundamental solutions, i.e. solutions to (Formula presented.), and use these solutions to find k-hypermonogenic kernels for a Cauchy-type integral formula in the upper half-space. AB - We consider the modified Cauchy–Riemann operator (Formula presented.) in the universal Clifford algebra (Formula presented.) with the basis (Formula presented.). The null-solutions of this operator are called k-hypermonogenic functions. We calculate the k-hyperbolic harmonic fundamental solutions, i.e. solutions to (Formula presented.), and use these solutions to find k-hypermonogenic kernels for a Cauchy-type integral formula in the upper half-space. KW - Cauchy integral formula KW - Clifford algebra KW - hyperbolic Laplace–Beltrami KW - k-hyperbolic harmonic KW - k-hypermonogenic U2 - 10.1080/17476933.2016.1250402 DO - 10.1080/17476933.2016.1250402 M3 - Article VL - 62 SP - 1 EP - 12 JO - Complex Variables and Elliptic Equations JF - Complex Variables and Elliptic Equations SN - 1747-6933 IS - 9 ER - TY - JOUR T1 - Internal model theory for distributed parameter systems AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 N2 - In this paper we consider robust output regulation of distributed parameter systems and the internal model principle. The main purpose is to generalize the internal model principle by Francis and Wonham for infinite-dimensional systems and clarify the relationships between different generalizations of the internal model. We also construct a signal generator capable of generating infinite-dimensional polynomially increasing signals. AB - In this paper we consider robust output regulation of distributed parameter systems and the internal model principle. The main purpose is to generalize the internal model principle by Francis and Wonham for infinite-dimensional systems and clarify the relationships between different generalizations of the internal model. We also construct a signal generator capable of generating infinite-dimensional polynomially increasing signals. U2 - 10.1137/090760957 DO - 10.1137/090760957 M3 - Article VL - 48 SP - 4753 EP - 4775 JO - SIAM Journal on Control and Optimization JF - SIAM Journal on Control and Optimization SN - 0363-0129 IS - 7 ER - TY - JOUR T1 - Interval decomposition lattices are balanced AU - Foldes, Stephane AU - Radeleczki, Sándor PY - 2016/9/1 Y1 - 2016/9/1 N2 - Intervals in binary or n-ary relations or other discrete structures generalize the concept of an interval in a linearly ordered set. They are defined abstractly as closed sets of a closure system on a set, satisfying certain axioms. Join-irreducible partitions into intervals are characterized in the lattice of all interval decompositions. This result is used to show that the lattice of interval decompositions is balanced, and the case when this lattice is distributive is also characterised. AB - Intervals in binary or n-ary relations or other discrete structures generalize the concept of an interval in a linearly ordered set. They are defined abstractly as closed sets of a closure system on a set, satisfying certain axioms. Join-irreducible partitions into intervals are characterized in the lattice of all interval decompositions. This result is used to show that the lattice of interval decompositions is balanced, and the case when this lattice is distributive is also characterised. KW - Balanced lattice KW - Closure system KW - Interval decomposition KW - Join-irreducible element KW - Semimodular lattice KW - Strong set U2 - 10.1515/dema-2016-0023 DO - 10.1515/dema-2016-0023 M3 - Article VL - 49 SP - 271 EP - 281 JO - DEMONSTRATIO MATHEMATICA JF - DEMONSTRATIO MATHEMATICA SN - 0420-1213 IS - 3 ER - TY - JOUR T1 - Interventions for second-order change in higher education: challenges and barriers AU - Fiedler, Sebastian AU - Väljataga, Terje N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Article VL - 8 SP - 85 EP - 92 JO - Electronic Journal of e-Learning JF - Electronic Journal of e-Learning SN - 1479-4403 IS - 2 ER - TY - JOUR T1 - Inverse problems of generalized projection operators AU - Kaasalainen, M. AU - Lamberg, L. N1 - Contribution: organisation=mat,FACT1=1 PY - 2006 Y1 - 2006 U2 - 10.1088/0266-5611/22/3/002 DO - 10.1088/0266-5611/22/3/002 M3 - Article VL - 22 SP - 749 EP - 769 JO - Inverse Problems JF - Inverse Problems SN - 0266-5611 IS - 3 ER - TY - JOUR T1 - Invertibility and Dedekind finiteness in structural matrix rings AU - Foldes, Stephan AU - Szigeti, Jeno AU - van Wyk, Leon N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1080/03081080903357653 DO - 10.1080/03081080903357653 M3 - Article VL - 59 SP - 221 EP - 227 JO - Linear and Multilinear Algebra JF - Linear and Multilinear Algebra SN - 0308-1087 IS - 2 ER - TY - JOUR T1 - Iterative alternating sequential (IAS) method for radio tomography of asteroids in 3D AU - Pursiainen, S. AU - Kaasalainen, M. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: Pergamon PY - 2013 Y1 - 2013 U2 - 10.1016/j.pss.2013.04.001 DO - 10.1016/j.pss.2013.04.001 M3 - Article VL - 82-83 SP - 84 EP - 98 JO - Planetary and Space Science JF - Planetary and Space Science SN - 0032-0633 ER - TY - JOUR T1 - Kalman filter with a linear state model for PDR+WLAN positioning and its application to assisting a particle filter AU - Raitoharju, Matti AU - Nurminen, Henri AU - Piché, Robert PY - 2015/12/1 Y1 - 2015/12/1 N2 - Indoor positioning based on wireless local area network (WLAN) signals is often enhanced using pedestrian dead reckoning (PDR) based on an inertial measurement unit. The state evolution model in PDR is usually nonlinear. We present a new linear state evolution model for PDR. In simulated-data and real-data tests of tightly coupled WLAN-PDR positioning, the positioning accuracy with this linear model is better than with the traditional models when the initial heading is not known, which is a common situation. The proposed method is computationally light and is also suitable for smoothing. Furthermore, we present modifications to WLAN positioning based on Gaussian coverage areas and show how a Kalman filter using the proposed model can be used for integrity monitoring and (re)initialization of a particle filter. AB - Indoor positioning based on wireless local area network (WLAN) signals is often enhanced using pedestrian dead reckoning (PDR) based on an inertial measurement unit. The state evolution model in PDR is usually nonlinear. We present a new linear state evolution model for PDR. In simulated-data and real-data tests of tightly coupled WLAN-PDR positioning, the positioning accuracy with this linear model is better than with the traditional models when the initial heading is not known, which is a common situation. The proposed method is computationally light and is also suitable for smoothing. Furthermore, we present modifications to WLAN positioning based on Gaussian coverage areas and show how a Kalman filter using the proposed model can be used for integrity monitoring and (re)initialization of a particle filter. KW - Computational modeling KW - Indoor positioning KW - Pedestrian dead reckoning KW - Wireless LAN UR - http://www.scopus.com/inward/record.url?scp=84928397748&partnerID=8YFLogxK U2 - 10.1186/s13634-015-0216-z DO - 10.1186/s13634-015-0216-z M3 - Article VL - 2015 JO - Eurasip Journal on Advances in Signal Processing JF - Eurasip Journal on Advances in Signal Processing SN - 1687-6172 IS - 1 M1 - 33 ER - TY - JOUR T1 - Kehittämistutkimus: vuorovaikutteisten Matlab-opetusohjelmien vaikutus minäpystyvyyteen ja oppimistuloksiin yliopistomatematiikassa AU - Kaarakka, Terhi Elina AU - Ali-Löytty, Simo AU - Huhtanen, Miika PY - 2018 Y1 - 2018 N2 - Tampereen teknillisessä yliopistossa luotiin keväällä 2017 kehittämistutkimuksena opetusmoduuli matriisilaskennan sekä MATLAB-ohjelmiston harjoitteluun. Moduulissa olevien vuorovaikutteisten opetusohjelmien yksi tavoite on vaikuttaa positiivisesti opiskelijoiden minäpystyvyyteen matematiikassa ja MATLABin käytössä. Tutkimuksen tässä vaiheessa selvitettiin eroja oppimistuloksissa sekä minäpystyvyyden muutoksissa opetusohjelmilla harjoittelevien ja itsenäisesti opiskelevien opiskelijoiden välillä. Tässä tutkimuksessa ei havaittu tilastollisesti merkitsevää eroa ryhmien välillä. Alkutilanteessa koeryhmän minäpystyvyystuntemukset eri mittareilla olivat matalampia, mutta erot tasoittuivat tutkimuksen aikana. Ryhmien epähomogeenisuus alussa heikentää tulosten yleistettävyyttä, mutta tulokset ovat lupaavia ja rohkaisevat tutkimaan asiaa enemmän. AB - Tampereen teknillisessä yliopistossa luotiin keväällä 2017 kehittämistutkimuksena opetusmoduuli matriisilaskennan sekä MATLAB-ohjelmiston harjoitteluun. Moduulissa olevien vuorovaikutteisten opetusohjelmien yksi tavoite on vaikuttaa positiivisesti opiskelijoiden minäpystyvyyteen matematiikassa ja MATLABin käytössä. Tutkimuksen tässä vaiheessa selvitettiin eroja oppimistuloksissa sekä minäpystyvyyden muutoksissa opetusohjelmilla harjoittelevien ja itsenäisesti opiskelevien opiskelijoiden välillä. Tässä tutkimuksessa ei havaittu tilastollisesti merkitsevää eroa ryhmien välillä. Alkutilanteessa koeryhmän minäpystyvyystuntemukset eri mittareilla olivat matalampia, mutta erot tasoittuivat tutkimuksen aikana. Ryhmien epähomogeenisuus alussa heikentää tulosten yleistettävyyttä, mutta tulokset ovat lupaavia ja rohkaisevat tutkimaan asiaa enemmän. M3 - Article VL - 2 SP - 67 EP - 77 JO - FMSERA Journal JF - FMSERA Journal SN - 2489-4583 IS - 1 ER - TY - JOUR T1 - Kriging prediction of stand-level forest information using mobile laser scanning data adjusted for nondetection AU - Saarela, Svetlana AU - Breidenbach, Johannes AU - Raumonen, Pasi AU - Grafström, Anton AU - Ståhl, Göran AU - Ducey, Mark J. AU - Astrup, Rasmus PY - 2017 Y1 - 2017 N2 - This study presents an approach for predicting stand-level forest attributes utilizing mobile laser scanning data collected as a nonprobability sample. Firstly, recordings of stem density were made at point locations every 10th metre along a subjectively chosen mobile laser scanning track in a forest stand. Secondly, kriging was applied to predict stem density values for the centre point of all grid cells in a 5 m x 5 m lattice across the stand. Thirdly, due to nondetectability issues, a correction term was computed based on distance sampling theory. Lastly, the mean stem density at stand level was predicted as the mean of the point-level predictions multiplied with the correction factor, and the corresponding variance was estimated. Many factors contribute to the uncertainty of the stand-level prediction; in the variance estimator, we accounted for the uncertainties due to kriging prediction and due to estimating a detectability model from the laser scanning data. The results from our new approach were found to correspond fairly well to estimates obtained using field measurements from an independent set of 54 circular sample plots. The predicted number of stems in the stand based on the proposed methodology was 1366 with a 12.9% relative standard error. The corresponding estimate based on the field plots was 1677 with a 7.5% relative standard error. AB - This study presents an approach for predicting stand-level forest attributes utilizing mobile laser scanning data collected as a nonprobability sample. Firstly, recordings of stem density were made at point locations every 10th metre along a subjectively chosen mobile laser scanning track in a forest stand. Secondly, kriging was applied to predict stem density values for the centre point of all grid cells in a 5 m x 5 m lattice across the stand. Thirdly, due to nondetectability issues, a correction term was computed based on distance sampling theory. Lastly, the mean stem density at stand level was predicted as the mean of the point-level predictions multiplied with the correction factor, and the corresponding variance was estimated. Many factors contribute to the uncertainty of the stand-level prediction; in the variance estimator, we accounted for the uncertainties due to kriging prediction and due to estimating a detectability model from the laser scanning data. The results from our new approach were found to correspond fairly well to estimates obtained using field measurements from an independent set of 54 circular sample plots. The predicted number of stems in the stand based on the proposed methodology was 1366 with a 12.9% relative standard error. The corresponding estimate based on the field plots was 1677 with a 7.5% relative standard error. KW - covariogram KW - detectability function KW - forest management KW - model-based inference KW - TREE STEM KW - ABOVEGROUND BIOMASS KW - ASSISTED ESTIMATION KW - SPACEBORNE LIDAR KW - BOUNDARY OVERLAP KW - AIRBORNE KW - INVENTORY KW - MODELS KW - SYSTEM KW - VOLUME U2 - 10.1139/cjfr-2017-0019 DO - 10.1139/cjfr-2017-0019 M3 - Article VL - 47 SP - 1257 EP - 1265 JO - CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE JF - CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE SN - 0045-5067 IS - 9 ER - TY - JOUR T1 - Kullback-Leibler Divergence Approach to Partitioned Update Kalman Filter AU - Raitoharju, Matti AU - García-Fernádez, Ángel AU - Piche, Robert PY - 2017 Y1 - 2017 N2 - Kalman filtering is a widely used framework for Bayesian estimation. The partitioned update Kalman filter applies a Kalman filter update in parts so that the most linear parts of measurements are applied first. In this paper, we generalize partitioned update Kalman filter, which requires the use of the second order extended Kalman filter, so that it can be used with any Kalman filter extension such as the unscented Kalman filter. To do so, we use a Kullback-Leibler divergence approach to measure the nonlinearity of the measurement, which is theoretically more sound than the nonlinearity measure used in the original partitioned update Kalman filter. Results show that the use of the proposed partitioned update filter improves the estimation accuracy. AB - Kalman filtering is a widely used framework for Bayesian estimation. The partitioned update Kalman filter applies a Kalman filter update in parts so that the most linear parts of measurements are applied first. In this paper, we generalize partitioned update Kalman filter, which requires the use of the second order extended Kalman filter, so that it can be used with any Kalman filter extension such as the unscented Kalman filter. To do so, we use a Kullback-Leibler divergence approach to measure the nonlinearity of the measurement, which is theoretically more sound than the nonlinearity measure used in the original partitioned update Kalman filter. Results show that the use of the proposed partitioned update filter improves the estimation accuracy. U2 - 10.1016/j.sigpro.2016.07.007 DO - 10.1016/j.sigpro.2016.07.007 M3 - Article VL - 130 JO - Signal Processing JF - Signal Processing SN - 0165-1684 ER - TY - JOUR T1 - LEADER T2 - fast estimates of asteroid shape elongation and spin latitude distributions from scarce photometry AU - Nortunen, Hari AU - Kaasalainen, Mikko PY - 2017 Y1 - 2017 N2 - Context. Many asteroid databases with lightcurve brightness measurements (e.g. WISE, Pan-STARRS1) contain enormous amounts of data for asteroid shape and spin modelling. While lightcurve inversion is not plausible for individual targets with scarce data, it is possible for large populations with thousands of asteroids, where the distributions of the shape and spin characteristics of the populations are obtainable.Aims. We aim to introduce a software implementation of a method that computes the joint shape elongation p and spin latitude β distributions for a population, with the brightness observations given in an asteroid database. Other main goals are to include a method for performing validity checks of the algorithm, and a tool for a statistical comparison of populations.Methods. The LEADER software package read the brightness measurement data for a user-defined subpopulation from a given database. The observations were used to compute estimates of the brightness variations of the population members. A cumulative distribution function (CDF) was constructed of these estimates. A superposition of known analytical basis functions yielded this CDF as a function of the (shape, spin) distribution. The joint distribution can be reconstructed by solving a linear constrained inverse problem. To test the validity of the method, the algorithm can be run with synthetic asteroid models, where the shape and spin characteristics are known, and by using the geometries taken from the examined database.Results. LEADER is a fast and robust software package for solving shape and spin distributions for large populations. There are major differences in the quality and coverage of measurements depending on the database used, so synthetic simulations are always necessary before a database can be reliably used. We show examples of differences in the results when switching to another database. AB - Context. Many asteroid databases with lightcurve brightness measurements (e.g. WISE, Pan-STARRS1) contain enormous amounts of data for asteroid shape and spin modelling. While lightcurve inversion is not plausible for individual targets with scarce data, it is possible for large populations with thousands of asteroids, where the distributions of the shape and spin characteristics of the populations are obtainable.Aims. We aim to introduce a software implementation of a method that computes the joint shape elongation p and spin latitude β distributions for a population, with the brightness observations given in an asteroid database. Other main goals are to include a method for performing validity checks of the algorithm, and a tool for a statistical comparison of populations.Methods. The LEADER software package read the brightness measurement data for a user-defined subpopulation from a given database. The observations were used to compute estimates of the brightness variations of the population members. A cumulative distribution function (CDF) was constructed of these estimates. A superposition of known analytical basis functions yielded this CDF as a function of the (shape, spin) distribution. The joint distribution can be reconstructed by solving a linear constrained inverse problem. To test the validity of the method, the algorithm can be run with synthetic asteroid models, where the shape and spin characteristics are known, and by using the geometries taken from the examined database.Results. LEADER is a fast and robust software package for solving shape and spin distributions for large populations. There are major differences in the quality and coverage of measurements depending on the database used, so synthetic simulations are always necessary before a database can be reliably used. We show examples of differences in the results when switching to another database. U2 - 10.1051/0004-6361/201731360 DO - 10.1051/0004-6361/201731360 M3 - Article VL - 608 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A91 ER - TY - JOUR T1 - Learner control and personal learning environment: a challenge for instructional design AU - Väljataga, Terje AU - Laanpere, Mart N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1080/10494820.2010.500546 DO - 10.1080/10494820.2010.500546 M3 - Article VL - 18 SP - 277 EP - 291 JO - Interactive Learning Environments JF - Interactive Learning Environments SN - 1049-4820 IS - 3 ER - TY - JOUR T1 - Main-belt binary asteroidal systems with circular orbits AU - Marchis, F. AU - Descamps, P. AU - Baek, M. AU - Harris, A. AU - Kaasalainen, M. AU - Berthier, J. AU - Hestroffer, D. AU - Vachier, F. N1 - Contribution: organisation=mat,FACT1=1 PY - 2008 Y1 - 2008 U2 - 10.1016/j.icarus.2008.03.007 DO - 10.1016/j.icarus.2008.03.007 M3 - Article VL - 196 SP - 97 EP - 118 JO - Icarus JF - Icarus SN - 0019-1035 ER - TY - JOUR T1 - Manifolds in electromagnetism and superconductor modelling: Using their properties to model critical current of twisted conductors in self-field with 2-D model AU - Stenvall, A. AU - Tarhasaari, T. AU - Grilli, F. AU - Raumonen, P. AU - Vojenciak, M. AU - Pellikka, M. N1 - Contribution: organisation=dee,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Portfolio EDEND: 2013-04-29

Publisher name: Pergamon PY - 2013 Y1 - 2013 U2 - 10.1016/j.cryogenics.2012.06.005 DO - 10.1016/j.cryogenics.2012.06.005 M3 - Article VL - 53 SP - 135 EP - 141 JO - Cryogenics JF - Cryogenics SN - 0011-2275 ER - TY - JOUR T1 - Maximal perpendicularity in certain Abelian groups AU - Mattila, Mika AU - Merikoski, Jorma K. AU - Haukkanen, Pentti AU - Tossavainen, Timo PY - 2017 Y1 - 2017 N2 - We define perpendicularity in an Abelian group G as a binary relation satisfying certain five axioms. Such a relation is maximal if it is not a subrelation of any other perpendicularity in G. A motivation for the study is that the poset (P, ⊆) of all perpendicularities in G is a lattice if G has a unique maximal perpendicularity, and only a meet-semilattice if not. We study the cardinality of the set of maximal perpendicularities and, on the other hand, conditions on the existence of a unique maximal perpendicularity in the following cases: G ≅ ℤn, G is finite, G is finitely generated, and G = ℤ ⊕ ℤ ⊕⋯. A few such conditions are found and a few conjectured. In studying ℝn, we encounter perpendicularity in a vector space. AB - We define perpendicularity in an Abelian group G as a binary relation satisfying certain five axioms. Such a relation is maximal if it is not a subrelation of any other perpendicularity in G. A motivation for the study is that the poset (P, ⊆) of all perpendicularities in G is a lattice if G has a unique maximal perpendicularity, and only a meet-semilattice if not. We study the cardinality of the set of maximal perpendicularities and, on the other hand, conditions on the existence of a unique maximal perpendicularity in the following cases: G ≅ ℤn, G is finite, G is finitely generated, and G = ℤ ⊕ ℤ ⊕⋯. A few such conditions are found and a few conjectured. In studying ℝn, we encounter perpendicularity in a vector space. KW - Abelian group KW - Perpendicularity U2 - 10.1515/ausm-2017-0016 DO - 10.1515/ausm-2017-0016 M3 - Article VL - 9 SP - 235 EP - 247 JO - ACTA UNIVERSITATIS SAPIENTIAE: MATHEMATICA JF - ACTA UNIVERSITATIS SAPIENTIAE: MATHEMATICA SN - 1844-6094 IS - 1 ER - TY - JOUR T1 - Mean Value Properties for the Weinstein Equation Using the Hyperbolic Metric AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - Tallennettu Online first

Contribution: organisation=mat,FACT1=1

Publisher name: Birkhäuser PY - 2013 Y1 - 2013 U2 - 10.1007/s11785-012-0280-4 DO - 10.1007/s11785-012-0280-4 M3 - Article VL - 7 SP - 1609 EP - 1621 JO - Complex Analysis and Operator Theory JF - Complex Analysis and Operator Theory SN - 1661-8254 IS - 5 ER - TY - JOUR T1 - Meeting a deadline T2 - shortest paths on stochastic directed acyclic graphs with information gathering AU - Lauri, Mikko AU - Ropponen, Aino AU - Ritala, Risto PY - 2017/4 Y1 - 2017/4 N2 - We consider the problem of an agent traversing a directed graph with the objective of maximizing the probability of reaching a goal node before a given deadline. Only the probability of the travel times of edges is known to the agent. The agent must balance between traversal actions towards the goal, and delays due to actions improving information about graph edge travel times. We describe the relationship of the problem to the more general partially observable Markov decision process. Further, we show that if edge travel times are independent and the underlying directed graph is acyclic, a closed loop solution can be computed. The solution specifies whether to execute a traversal or information-gathering action as a function of the current node, the time remaining until the deadline, and the information about edge travel times. We present results from two case studies, quantifying the usefulness of information-gathering as opposed to applying only traversal actions. AB - We consider the problem of an agent traversing a directed graph with the objective of maximizing the probability of reaching a goal node before a given deadline. Only the probability of the travel times of edges is known to the agent. The agent must balance between traversal actions towards the goal, and delays due to actions improving information about graph edge travel times. We describe the relationship of the problem to the more general partially observable Markov decision process. Further, we show that if edge travel times are independent and the underlying directed graph is acyclic, a closed loop solution can be computed. The solution specifies whether to execute a traversal or information-gathering action as a function of the current node, the time remaining until the deadline, and the information about edge travel times. We present results from two case studies, quantifying the usefulness of information-gathering as opposed to applying only traversal actions. KW - Applied probability KW - Decision processes KW - Dynamic programming KW - Markov processes KW - Transportation U2 - 10.1007/s10472-016-9527-5 DO - 10.1007/s10472-016-9527-5 M3 - Article VL - 79 SP - 337 EP - 370 JO - Annals of Mathematics and Artificial Intelligence JF - Annals of Mathematics and Artificial Intelligence SN - 1012-2443 IS - 4 ER - TY - JOUR T1 - Minimal Characterization of O-notation in Algorithm Analysis AU - Rutanen, Kalle PY - 2018/2 Y1 - 2018/2 N2 - Previously, we showed that linear dominance is the only definition of O-notation suitable for algorithm analysis [1,2]. Linear dominance was characterized by 8 primitive properties as a down-set of a non-trivial scale-invariant preorder which is preserved under certain modifications to algorithms and is consistent with pointwise partial order. In this paper, we provide a minimal characterization of O-notation, where there are no redundant properties. Such is given by excluding locality from primitive properties. AB - Previously, we showed that linear dominance is the only definition of O-notation suitable for algorithm analysis [1,2]. Linear dominance was characterized by 8 primitive properties as a down-set of a non-trivial scale-invariant preorder which is preserved under certain modifications to algorithms and is consistent with pointwise partial order. In this paper, we provide a minimal characterization of O-notation, where there are no redundant properties. Such is given by excluding locality from primitive properties. KW - O-notation KW - characterization KW - minimal U2 - 10.1016/j.tcs.2017.12.026 DO - 10.1016/j.tcs.2017.12.026 M3 - Article VL - 713 SP - 31 EP - 41 JO - Theoretical Computer Science JF - Theoretical Computer Science SN - 0304-3975 ER - TY - JOUR T1 - Minimal solutions of general fuzzy relation equations on linear carriers. An algebraic characterization AU - Diaz-Moreno, Juan Carlos AU - Medina, Jesus AU - Turunen, Esko PY - 2017 Y1 - 2017 N2 - This paper considers a general fuzzy relation equation, which has minimal solutions, if it is solvable. In this case, an algebraic characterization is introduced which provides an interesting method to compute minimal solutions in this general setting. Moreover, a comparison with other frameworks is also given. AB - This paper considers a general fuzzy relation equation, which has minimal solutions, if it is solvable. In this case, an algebraic characterization is introduced which provides an interesting method to compute minimal solutions in this general setting. Moreover, a comparison with other frameworks is also given. U2 - 10.1016/j.fss.2016.02.004 DO - 10.1016/j.fss.2016.02.004 M3 - Article VL - 311 SP - 112 EP - 123 JO - Fuzzy Sets and Systems JF - Fuzzy Sets and Systems SN - 0165-0114 ER - TY - JOUR T1 - Minors of Boolean functions with respect to clique functions and hypergraph homomorphisms AU - Lehtonen, Erkko AU - Nesetril, Jaroslav N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1016/j.ejc.2010.05.007 DO - 10.1016/j.ejc.2010.05.007 M3 - Article VL - 31 SP - 1981 EP - 1995 JO - European Journal of Combinatorics JF - European Journal of Combinatorics SN - 0195-6698 IS - 8 ER - TY - JOUR T1 - Mixture surrogate models based on Dempster-Shafer theory for global optimization problems AU - Muller, Juliane AU - Piche, Robert N1 - Online first

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 N2 - Recent research in algorithms for solving global optimization problems using response surface methodology has shown that it is in general not possible to use one surrogate model for solving different kinds of problems. In this paper the approach of applying Dempster-Shafer theory to surrogate model selection and their combination is described. Various conflict redistribution rules have been examined with respect to their influence on the results. Furthermore, the implications of the surrogate model type, i.e. using combined, single or a hybrid of both, have been studied. The suggested algorithms were applied to several well-known global optimization test problems. The results indicate that the used approach leads for all problems to a thorough exploration of the variable domain, i.e. the vicinities of global optima could be detected, and that the global minima could in most cases be approximated with high accuracy. AB - Recent research in algorithms for solving global optimization problems using response surface methodology has shown that it is in general not possible to use one surrogate model for solving different kinds of problems. In this paper the approach of applying Dempster-Shafer theory to surrogate model selection and their combination is described. Various conflict redistribution rules have been examined with respect to their influence on the results. Furthermore, the implications of the surrogate model type, i.e. using combined, single or a hybrid of both, have been studied. The suggested algorithms were applied to several well-known global optimization test problems. The results indicate that the used approach leads for all problems to a thorough exploration of the variable domain, i.e. the vicinities of global optima could be detected, and that the global minima could in most cases be approximated with high accuracy. U2 - 10.1007/s10898-010-9620-y DO - 10.1007/s10898-010-9620-y M3 - Article VL - 51 SP - 79 EP - 104 JO - Journal of Global Optimization JF - Journal of Global Optimization SN - 0925-5001 IS - 1 ER - TY - JOUR T1 - Mobile Context-Aware Systems T2 - Technologies, Resources and Applications AU - Rivero-Rodriguez, Alejandro AU - Pileggi, Paolo AU - Nykänen, Ossi Antero PY - 2016 Y1 - 2016 N2 - Mobile applications often adapt their behavior according to user context, however, they are often limited to consider few sources of contextual information, such as user position or language. This article reviews existing work in context-aware systems (CAS), e.g., how to model context, and discusses further development of CAS and its potential applications by looking at available information, methods and technologies. Social Media seems to be an interesting source of personal information when appropriately exploited. In addition, there are many types of general information, ranging from weather and public transport to information of books and museums. These information sources can be combined in previously unexplored ways, enabling the development of smarter mobile services in different domains. Users are, however, reluctant to provide their personal information to applications; therefore, there is a crave for new regulations and systems that allow applications to use such contextual data without compromising the user privacy. AB - Mobile applications often adapt their behavior according to user context, however, they are often limited to consider few sources of contextual information, such as user position or language. This article reviews existing work in context-aware systems (CAS), e.g., how to model context, and discusses further development of CAS and its potential applications by looking at available information, methods and technologies. Social Media seems to be an interesting source of personal information when appropriately exploited. In addition, there are many types of general information, ranging from weather and public transport to information of books and museums. These information sources can be combined in previously unexplored ways, enabling the development of smarter mobile services in different domains. Users are, however, reluctant to provide their personal information to applications; therefore, there is a crave for new regulations and systems that allow applications to use such contextual data without compromising the user privacy. KW - Context-aware Services KW - Context Awareness KW - Context Management KW - Mobile Computing U2 - 10.3991/ijim.v10i2.5367 DO - 10.3991/ijim.v10i2.5367 M3 - Article VL - 10 SP - 25 EP - 32 JO - International Journal of Interactive Mobile Technologies JF - International Journal of Interactive Mobile Technologies SN - 1865-7923 IS - 2 ER - TY - JOUR T1 - Mobile Tracking in Mixed Line-of-Sight/Non-Line-of-Sight Conditions: Algorithm and Theoretical Lower Bound AU - Chen, Liang AU - Ali-Löytty, Simo AU - Piche, Robert AU - Wu, Lenan N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Springer PY - 2012 Y1 - 2012 N2 - The paper investigates the problem of mobile tracking in mixed line-of-sight (LOS)/non-line-of-sight (NLOS) conditions. The motion of mobile station is modeled by a dynamic white noise acceleration model, while the measurements are time of arrival (TOA). A first-order Markov model is employed to describe the dynamic transition of LOS/NLOS conditions. An improved Rao-Blackwellized particle filter (RBPF) is proposed, in which the LOS/NLOS sight conditions are estimated by particle filtering using the optimal trial distribution, and the mobile state is computed by applying approximated analytical methods. The theoretical error lower bound is further studied in the described problem. A new method is presented to compute the posterior Cramer-Rao lower bound (CRLB): the mobile state is first estimated by decentralized extended Kalman filter (EKF) method, then sigma point set and unscented transformation are applied to calculate Fisher information matrix (FIM). Simulation results show that the improved RBPF is more accurate than current methods, and its performance approaches to the theoretical bound. AB - The paper investigates the problem of mobile tracking in mixed line-of-sight (LOS)/non-line-of-sight (NLOS) conditions. The motion of mobile station is modeled by a dynamic white noise acceleration model, while the measurements are time of arrival (TOA). A first-order Markov model is employed to describe the dynamic transition of LOS/NLOS conditions. An improved Rao-Blackwellized particle filter (RBPF) is proposed, in which the LOS/NLOS sight conditions are estimated by particle filtering using the optimal trial distribution, and the mobile state is computed by applying approximated analytical methods. The theoretical error lower bound is further studied in the described problem. A new method is presented to compute the posterior Cramer-Rao lower bound (CRLB): the mobile state is first estimated by decentralized extended Kalman filter (EKF) method, then sigma point set and unscented transformation are applied to calculate Fisher information matrix (FIM). Simulation results show that the improved RBPF is more accurate than current methods, and its performance approaches to the theoretical bound. U2 - 10.1007/s11277-011-0294-7 DO - 10.1007/s11277-011-0294-7 M3 - Article VL - 65 SP - 753 EP - 771 JO - WIRELESS PERSONAL COMMUNICATIONS JF - WIRELESS PERSONAL COMMUNICATIONS SN - 0929-6212 IS - 4 ER - TY - JOUR T1 - Modeling of Neuronal Growth In Vitro: Comparison of Simulation Tools NETMORPH and CX3D AU - Acimovic, Jugoslava AU - Mäki-Marttunen, Tuomo AU - Havela, Riikka AU - Teppola, Heidi AU - Linne, Marja-Leena N1 - ei ut-numeroa 12.10.2013

Contribution: organisation=sgn,FACT1=0.9

Contribution: organisation=mat,FACT2=0.1 PY - 2011 Y1 - 2011 N2 - We simulate the growth of neuronal networks using the two recently published tools, NETMORPH and CX3D. The goals of the work are (1) to examine and compare the simulation tools, (2) to construct a model of growth of neocortical cultures, and (3) to characterize the changes in network connectivity during growth, using standard graph theoretic methods. Parameters for the neocortical culture are chosen after consulting both the experimental and the computational work presented in the literature. The first (three) weeks in culture are known to be a time of development of extensive dendritic and axonal arbors and establishment of synaptic connections between the neurons. We simulate the growth of networks from day 1 to day 21. It is shown that for the properly selected parameters, the simulators can reproduce the experimentally obtained connectivity. The selected graph theoretic methods can capture the structural changes during growth. AB - We simulate the growth of neuronal networks using the two recently published tools, NETMORPH and CX3D. The goals of the work are (1) to examine and compare the simulation tools, (2) to construct a model of growth of neocortical cultures, and (3) to characterize the changes in network connectivity during growth, using standard graph theoretic methods. Parameters for the neocortical culture are chosen after consulting both the experimental and the computational work presented in the literature. The first (three) weeks in culture are known to be a time of development of extensive dendritic and axonal arbors and establishment of synaptic connections between the neurons. We simulate the growth of networks from day 1 to day 21. It is shown that for the properly selected parameters, the simulators can reproduce the experimentally obtained connectivity. The selected graph theoretic methods can capture the structural changes during growth. U2 - 10.1155/2011/616382 DO - 10.1155/2011/616382 M3 - Article VL - 2011 SP - 1 EP - 13 JO - Eurasip Journal on Bioinformatics and Systems Biology JF - Eurasip Journal on Bioinformatics and Systems Biology SN - 1687-4145 M1 - 616382 ER - TY - JOUR T1 - Modelling anisotropy in non-oriented electrical steel sheet using vector Jiles-Atherton model AU - Upadhaya, Brijesh AU - Martin, Floran AU - Rasilo, Paavo AU - Handgruber, Paul AU - Belahcen, Anouar AU - Arkkio, Antero PY - 2017 Y1 - 2017 U2 - 10.1108/COMPEL-09-2016-0399 DO - 10.1108/COMPEL-09-2016-0399 M3 - Article VL - 36 SP - 764 EP - 773 JO - COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering JF - COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering SN - 0332-1649 IS - 3 ER - TY - JOUR T1 - Modifications of the 85/85 test and the temperature cycling test for tantalum capacitors AU - Virkki, Johanna AU - Sydänheimo, Lauri AU - Raumonen, Pasi N1 - Tulospisteet 90 % ELE / 10 % MAT

Contribution: organisation=ele,FACT1=0.9

Contribution: organisation=mat,FACT2=0.1 PY - 2011 Y1 - 2011 U2 - 10.1108/09540911111146926 DO - 10.1108/09540911111146926 M3 - Article VL - 23 SP - 168 EP - 176 JO - Soldering and Surface Mount Technology JF - Soldering and Surface Mount Technology SN - 0954-0911 IS - 3 ER - TY - JOUR T1 - Multicolor, rotationally resolved photometry of asteroid 21 Lutetia from Osiris/Rosetta observations AU - Lamy, P. AU - Faury, G. AU - Jorda, L. AU - Kaasalainen, Mikko AU - Hviid, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1051/0004-6361/201014452 DO - 10.1051/0004-6361/201014452 M3 - Article VL - 521 SP - 1 EP - 10 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - A19 ER - TY - JOUR T1 - Multigrid-Based Inversion for Volumetric Radar Imaging With Asteroid Interior Reconstruction as a Potential Application AU - Takala, M. AU - Us, D. AU - Pursiainen, S. PY - 2018/6/1 Y1 - 2018/6/1 N2 - This study concentrates on advancing mathematical and computational methodology for radar tomography imaging in which the unknown volumetric velocity distribution of a wave within a bounded domain is to be reconstructed. Our goal is to enable effective simulation and inversion of a large amount of full-wave data within a realistic 2-D or 3-D geometry. For propagating and inverting the wave, we present a rigorous multigrid-based forward approach that utilizes the finite-difference time-domain method and a nested finite element grid structure. We also introduce and validate a multigrid-based inversion algorithm that allows regularization of the unknown distribution through a coarse-to-fine inversion scheme. Using this approach, sparse signals can be effectively inverted, as the coarse fluctuations are reconstructed before the finer ones. Furthermore, the number of nonzero entries in the system matrix can be compressed and, thus, the inversion procedure can be speeded up. As the test scenario, we investigate satellite-based asteroid interior reconstruction. We use both full-wave and projected wave data and estimate the accuracy of the inversion under different error sources: noise and positioning inaccuracies. The results suggest that the present inversion technique allows recovering the interior with a single satellite recording backscattering data. Robust results can be achieved, when the peak-to-peak signal-to-noise ratio is above 10 dB. Furthermore, the robustness for the deep interior part can be enhanced if two satellites can be utilized in the measurements. AB - This study concentrates on advancing mathematical and computational methodology for radar tomography imaging in which the unknown volumetric velocity distribution of a wave within a bounded domain is to be reconstructed. Our goal is to enable effective simulation and inversion of a large amount of full-wave data within a realistic 2-D or 3-D geometry. For propagating and inverting the wave, we present a rigorous multigrid-based forward approach that utilizes the finite-difference time-domain method and a nested finite element grid structure. We also introduce and validate a multigrid-based inversion algorithm that allows regularization of the unknown distribution through a coarse-to-fine inversion scheme. Using this approach, sparse signals can be effectively inverted, as the coarse fluctuations are reconstructed before the finer ones. Furthermore, the number of nonzero entries in the system matrix can be compressed and, thus, the inversion procedure can be speeded up. As the test scenario, we investigate satellite-based asteroid interior reconstruction. We use both full-wave and projected wave data and estimate the accuracy of the inversion under different error sources: noise and positioning inaccuracies. The results suggest that the present inversion technique allows recovering the interior with a single satellite recording backscattering data. Robust results can be achieved, when the peak-to-peak signal-to-noise ratio is above 10 dB. Furthermore, the robustness for the deep interior part can be enhanced if two satellites can be utilized in the measurements. KW - finite difference time-domain analysis KW - geometry KW - inverse problems KW - radar imaging KW - tomography KW - unknown volumetric velocity distribution KW - bounded domain KW - full-wave data KW - 3-D geometry KW - rigorous multigrid-based forward approach KW - finite-difference time-domain method KW - nested finite element grid structure KW - multigrid-based inversion algorithm KW - coarse-to-fine inversion scheme KW - asteroid interior reconstruction KW - inversion technique KW - single satellite recording backscattering data KW - peak-to-peak signal-to-noise ratio KW - deep interior part KW - volumetric radar imaging KW - mathematical methodology KW - computational methodology KW - radar tomography imaging KW - Image reconstruction KW - Solar system KW - Radar imaging KW - Permittivity KW - Tomography KW - Computational modeling KW - Multigrid methods KW - radio tomography KW - microw-ave tomography KW - asteroids KW - biomedical imaging U2 - 10.1109/TCI.2018.2811908 DO - 10.1109/TCI.2018.2811908 M3 - Article VL - 4 SP - 228 EP - 240 JO - IEEE Transactions on Computational Imaging JF - IEEE Transactions on Computational Imaging SN - 2333-9403 IS - 2 ER - TY - JOUR T1 - Multimodal inverse problems: maximum compatibility estimate and shape reconstruction AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.3934/ipi.2011.5.37 DO - 10.3934/ipi.2011.5.37 M3 - Article VL - 5 SP - 37 EP - 57 JO - Inverse Problems and Imaging JF - Inverse Problems and Imaging SN - 1930-8337 IS - 1 ER - TY - JOUR T1 - Multiplierless filtered-OFDM transmitter for narrow-band IoT devices AU - Loulou, Alaa Eddin AU - Yli-Kaakinen, Juha AU - Levanen, Toni AU - Lehtinen, Vesa AU - Schaich, Frank AU - Wild, Thorsten AU - Renfors, Markku AU - Valkama, Mikko PY - 2020/2/13 Y1 - 2020/2/13 N2 - In cyclic-prefix orthogonal frequency-division multiplexing (CP-OFDM) based radio access, the coexistence of different technologies without precise time-frequency synchronization is limited due to high out-of-band emissions. Therefore, spectrum enhancement techniques play a key role to relax the synchronization and power control requirements. This allows higher degree of opportunistic spectrum use with minimized interference. In addition, all transmitting devices have to fulfill specific transmitted signal quality requirements, including the maximum out-of-band radiated signal power. With OFDM based radio access, some additional signal processing for improved spectrum containment is commonly needed to achieve these requirements. Filtering and time-domain windowing are two fundamentally different approaches for spectrum enhancement. Filtered OFDM (F-OFDM) provides better spectrum localization than the timewindowing schemes (such as windowed overlap-add, WOLA), with the cost of higher complexity. This paper introduces lowcomplexity solutions for spectrally enhanced narrow-band OFDM transmitters based on the use of a look-up tables (LUTs). The proposed LUT approach, requiring only memory units and a low number of additions, allows to avoid all computationally expensive operations in on-line transmitter processing, as it builds the transmitted signal by summing the stored partial waveforms optimized off-line. In certain cases, completely multiplication and summation free designs are possible. The transmitters of narrowband Internet of things (NB-IoT) devices are natural applications for the proposed LUT approach, as they require additional digital baseband signal processing to reach the emission requirements. It is shown that the proposed LUT schemes can provide signicant savings in real-time computations of NB-IoT devices, while fulfilling the 3GPP requirements. AB - In cyclic-prefix orthogonal frequency-division multiplexing (CP-OFDM) based radio access, the coexistence of different technologies without precise time-frequency synchronization is limited due to high out-of-band emissions. Therefore, spectrum enhancement techniques play a key role to relax the synchronization and power control requirements. This allows higher degree of opportunistic spectrum use with minimized interference. In addition, all transmitting devices have to fulfill specific transmitted signal quality requirements, including the maximum out-of-band radiated signal power. With OFDM based radio access, some additional signal processing for improved spectrum containment is commonly needed to achieve these requirements. Filtering and time-domain windowing are two fundamentally different approaches for spectrum enhancement. Filtered OFDM (F-OFDM) provides better spectrum localization than the timewindowing schemes (such as windowed overlap-add, WOLA), with the cost of higher complexity. This paper introduces lowcomplexity solutions for spectrally enhanced narrow-band OFDM transmitters based on the use of a look-up tables (LUTs). The proposed LUT approach, requiring only memory units and a low number of additions, allows to avoid all computationally expensive operations in on-line transmitter processing, as it builds the transmitted signal by summing the stored partial waveforms optimized off-line. In certain cases, completely multiplication and summation free designs are possible. The transmitters of narrowband Internet of things (NB-IoT) devices are natural applications for the proposed LUT approach, as they require additional digital baseband signal processing to reach the emission requirements. It is shown that the proposed LUT schemes can provide signicant savings in real-time computations of NB-IoT devices, while fulfilling the 3GPP requirements. U2 - 10.1109/JIOT.2019.2945186 DO - 10.1109/JIOT.2019.2945186 M3 - Article VL - 7 SP - 846 EP - 862 JO - IEEE Internet of Things Journal JF - IEEE Internet of Things Journal SN - 2327-4662 IS - 2 ER - TY - JOUR T1 - Multi-stable dynamics of the non-adiabatic repressilator AU - Potapov, Ilya AU - Zhurov, Boris AU - Volkov, Evgeny PY - 2015/3/6 Y1 - 2015/3/6 N2 - The assumption of the fast binding of transcription factors (TFs) to promoters is a typical point in studies of synthetic genetic circuits functioning in bacteria. Although the assumption is effective for simplifying the models, it becomes questionable in the light of in vivo measurements of the times TF spends searching for its cognate DNA sites. We investigated the dynamics of the full idealized model of the paradigmatic genetic oscillator, the repressilator, using deterministic mathematical modelling and stochastic simulations. We found (using experimentally approved parameter values) that decreases in the TF binding rate changes the type of transition between steady state and oscillation. As a result, this gives rise to the hysteresis region in the parameter space, where both the steady state and the oscillation coexist. We further show that the hysteresis is persistent over a considerable range of the parameter values, but the presence of the oscillations is limited by the low rate of TF dimer degradation. Finally, the stochastic simulation of the model confirms the hysteresis with switching between the two attractors, resulting in highly skewed period distributions. Moreover, intrinsic noise stipulates trains of large-amplitude modulations around the stable steady state outside the hysteresis region, which makes the period distributions bimodal. AB - The assumption of the fast binding of transcription factors (TFs) to promoters is a typical point in studies of synthetic genetic circuits functioning in bacteria. Although the assumption is effective for simplifying the models, it becomes questionable in the light of in vivo measurements of the times TF spends searching for its cognate DNA sites. We investigated the dynamics of the full idealized model of the paradigmatic genetic oscillator, the repressilator, using deterministic mathematical modelling and stochastic simulations. We found (using experimentally approved parameter values) that decreases in the TF binding rate changes the type of transition between steady state and oscillation. As a result, this gives rise to the hysteresis region in the parameter space, where both the steady state and the oscillation coexist. We further show that the hysteresis is persistent over a considerable range of the parameter values, but the presence of the oscillations is limited by the low rate of TF dimer degradation. Finally, the stochastic simulation of the model confirms the hysteresis with switching between the two attractors, resulting in highly skewed period distributions. Moreover, intrinsic noise stipulates trains of large-amplitude modulations around the stable steady state outside the hysteresis region, which makes the period distributions bimodal. KW - Adiabatic KW - Bimodality KW - Genetic oscillator KW - Hysteresis KW - Multi-stability UR - http://www.scopus.com/inward/record.url?scp=84923240824&partnerID=8YFLogxK U2 - 10.1098/rsif.2014.1315 DO - 10.1098/rsif.2014.1315 M3 - Article VL - 12 JO - Journal of the Royal Society. Interface JF - Journal of the Royal Society. Interface SN - 1742-5689 IS - 104 M1 - 20141315 ER - TY - JOUR T1 - Nanosatellite attitude estimation using Kalman-type filters with non-Gaussian noise AU - Cilden-Guler, Demet AU - Raitoharju, Matti AU - Piche, Robert AU - Hajiyev, Chingiz PY - 2019/9 Y1 - 2019/9 N2 - In order to control the orientation of a satellite, it is important to estimate the attitude accurately. Time series estimation is especially important in micro and nanosatellites, whose sensors are usually low-cost and have higher noise levels than high end sensors. Also, the algorithms should be able to run on systems with very restricted computer power. In this work, we evaluate five Kalman-type filtering algorithms for attitude estimation with 3-axis magnetometer and sun sensor measurements. The Kalman-type filters are selected so that each of them is designed to mitigate one error source for the unscented Kalman filter that is used as baseline. We investigate the distribution of the magnetometer noises and show that the Student's t-distribution is a better model for them than the Gaussian distribution. We consider filter responses in four operation modes: steady state, recovery from incorrect initial state, short-term sensor noise increment, and long-term increment. We find that a Kalman-type filter designed for Student's t sensor noises has the best combination of accuracy and computational speed for these problems, which leads to a conclusion that one can achieve more improvements in estimation accuracy by using a filter that can work with heavy tailed noise than by using a nonlinearity minimizing filter that assumes Gaussian noise. AB - In order to control the orientation of a satellite, it is important to estimate the attitude accurately. Time series estimation is especially important in micro and nanosatellites, whose sensors are usually low-cost and have higher noise levels than high end sensors. Also, the algorithms should be able to run on systems with very restricted computer power. In this work, we evaluate five Kalman-type filtering algorithms for attitude estimation with 3-axis magnetometer and sun sensor measurements. The Kalman-type filters are selected so that each of them is designed to mitigate one error source for the unscented Kalman filter that is used as baseline. We investigate the distribution of the magnetometer noises and show that the Student's t-distribution is a better model for them than the Gaussian distribution. We consider filter responses in four operation modes: steady state, recovery from incorrect initial state, short-term sensor noise increment, and long-term increment. We find that a Kalman-type filter designed for Student's t sensor noises has the best combination of accuracy and computational speed for these problems, which leads to a conclusion that one can achieve more improvements in estimation accuracy by using a filter that can work with heavy tailed noise than by using a nonlinearity minimizing filter that assumes Gaussian noise. U2 - 10.1016/j.ast.2019.05.055 DO - 10.1016/j.ast.2019.05.055 M3 - Article VL - 92 SP - 66 EP - 76 JO - Aerospace Science and Technology JF - Aerospace Science and Technology SN - 1270-9638 ER - TY - JOUR T1 - New determination of the size and bulk density of binary asteroid 22 Kalliope from observations of mutual eclipses AU - Descamps, P. AU - Marchis, F. AU - Pollock, J. AU - Berthier, J. AU - Vachier, F. AU - Birlan, M. AU - Kaasalainen, M. AU - Harris, A.W. AU - Wong, M.H. AU - Romanishin, W.J. AU - Cooper, E.M. AU - Kettner, K.A. AU - Wiggins, P. AU - Kryszczynska, A. AU - Polinska, M. AU - Coliac, J.-F. AU - Devyatkin, A. AU - Verestchagina, I. AU - Gorshanov, D. N1 - Contribution: organisation=mat,FACT1=1 PY - 2008 Y1 - 2008 U2 - 10.1016/j.icarus.2008.10.001 DO - 10.1016/j.icarus.2008.10.001 M3 - Article VL - 196 SP - 578 EP - 600 JO - Icarus JF - Icarus SN - 0019-1035 ER - TY - JOUR T1 - New Insights for Relational Capital AU - Still, Kaisa AU - Huhtamäki, Jukka AU - Russell, Martha G. PY - 2015 Y1 - 2015 N2 - In this paper, we concentrate on relational capital, manifestation of the old adage ”it is not what you know but who you know”. We propose that in this networked world, the importance of relationships between multiple stakeholders created by key personnel and financing becomes fundamental, and hence understanding and measuring those becomes fundamental, too. Accordingly, we highlight a need to go beyond social, individual or personal relationships and organizational context, as well as beyond the limitations of the dyadic (one actor to one actor) view on relationships. Hence, we are introducing the ecosystem as the context for measuring relational capital. This paper builds on a construct of ecosystemic relational capital, created for understanding and measuring the importance of relationships in the context of ecosystems. It looks at the totality of relationships both at organizational level and at individual level, measuring the structures and characteristics related to individuals, organizations as well as the ecosystem as a whole (Still et al. 2014a). We acknowledge that the initial framework emphasizes the “networking capabilities” element of relational capital, with less attention to the element of “customer loyalty and reputation”, which is the motivation for building on the construct. The processes of ecosystemic relational capital are built on the possibilities afforded by the volumes of digital data, mostly from social media, providing details on the relationships between various actors related to various regions, sectors, technologies and products. However, we propose enhancing the holistic integration for better understanding and measuring of relational capital with the application of methods of social network analysis (SNA), network visualizations and social media analytics. In this paper, we present concrete examples of the enhanced framework. At the same time, we acknowledge that there are many other avenues for obtaining novel insights for relational capital with these analytics, and we strongly encourage researchers and practitioners to do so. AB - In this paper, we concentrate on relational capital, manifestation of the old adage ”it is not what you know but who you know”. We propose that in this networked world, the importance of relationships between multiple stakeholders created by key personnel and financing becomes fundamental, and hence understanding and measuring those becomes fundamental, too. Accordingly, we highlight a need to go beyond social, individual or personal relationships and organizational context, as well as beyond the limitations of the dyadic (one actor to one actor) view on relationships. Hence, we are introducing the ecosystem as the context for measuring relational capital. This paper builds on a construct of ecosystemic relational capital, created for understanding and measuring the importance of relationships in the context of ecosystems. It looks at the totality of relationships both at organizational level and at individual level, measuring the structures and characteristics related to individuals, organizations as well as the ecosystem as a whole (Still et al. 2014a). We acknowledge that the initial framework emphasizes the “networking capabilities” element of relational capital, with less attention to the element of “customer loyalty and reputation”, which is the motivation for building on the construct. The processes of ecosystemic relational capital are built on the possibilities afforded by the volumes of digital data, mostly from social media, providing details on the relationships between various actors related to various regions, sectors, technologies and products. However, we propose enhancing the holistic integration for better understanding and measuring of relational capital with the application of methods of social network analysis (SNA), network visualizations and social media analytics. In this paper, we present concrete examples of the enhanced framework. At the same time, we acknowledge that there are many other avenues for obtaining novel insights for relational capital with these analytics, and we strongly encourage researchers and practitioners to do so. M3 - Article VL - 13 SP - 167 EP - 182 JO - Electronic Journal of Knowledge Management JF - Electronic Journal of Knowledge Management SN - 1479-4411 IS - 1 ER - TY - JOUR T1 - New insights on the binary asteroid 121 Hermione AU - Descamps, P. AU - Marchis, F. AU - Durech, J. AU - Emery, J. AU - Harris, A.W. AU - Kaasalainen, M. AU - Berthier, J. AU - Teng-Chuen-Yu, J.-P. AU - Peyrot, A. AU - Hutton, L. AU - Greene, J. AU - Pollock, J. AU - Assafin, M. AU - Vieira-Martins, R. AU - Camargo, J.I.B. AU - Braga-Ribas, F. AU - Vachier, F. AU - Reichart, D.E. AU - Ivarsen, K.M. AU - Crain, J.A. AU - Nysewander, M.C. AU - Lacluyze, A.P. AU - Haislip, J.B. AU - Behrend, R. AU - Colas, F. AU - Lecaheux, J. AU - Bernasconi, L. AU - Roy, R. AU - Baudouin, P. AU - Brunetto, L. AU - Sposetti, S. AU - Manzini, F. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 U2 - 10.1016/j.icarus.2009.04.032 DO - 10.1016/j.icarus.2009.04.032 M3 - Article VL - 203 SP - 88 EP - 101 JO - Icarus JF - Icarus SN - 0019-1035 ER - TY - JOUR T1 - New photometric observations of asteroids (1862) Apollo and (25143) Itokawa - analysis of YORP effect AU - Durech, J. AU - Vokrouhlicky, D. AU - Kaasalainen, M. AU - Weissman, P. AU - Lowry, S.C. AU - Beshore, E. AU - Higgins, D. AU - Krugly, Y.N. AU - Shevchenko, V.G. AU - Gaftonyuk, N.M. AU - Choi, Y.-J. AU - Kowalski, R.A. AU - Larson, S. AU - Warner, B.D. AU - Marshalkina, A.L. AU - Ibrahimov, M.A. AU - Molotov, I.E. AU - Michalowski, T. AU - Kitazato, K. N1 - Contribution: organisation=mat,FACT1=1 PY - 2008 Y1 - 2008 U2 - 10.1051/0004-6361:200809663 DO - 10.1051/0004-6361:200809663 M3 - Article VL - 488 SP - 345 EP - 350 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 ER - TY - JOUR T1 - n-Fold implicative basic logic is Gödel logic AU - Turunen, Esko AU - Tchikapa, Nganteu AU - Lele, Celestin N1 - Online first

Contribution: organisation=mat,FACT1=1

Publisher name: Springer PY - 2012 Y1 - 2012 U2 - 10.1007/s00500-011-0761-9 DO - 10.1007/s00500-011-0761-9 M3 - Article VL - 16 SP - 177 EP - 181 JO - Soft Computing JF - Soft Computing SN - 1432-7643 IS - 1 ER - TY - JOUR T1 - Nondestructive estimates of above-ground biomass using terrestrial laser scanning AU - Calders, Kim AU - Newnhamn, Glenn AU - Burt, Andrew AU - Murphy, Simon AU - Raumonen, Pasi AU - Herold, Martin AU - Culvenor, Darius AU - Avitable, Valerio AU - Disney, Mathias AU - Armston, John AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-16

Publisher name: Wiley-Blackwell Publishing PY - 2015 Y1 - 2015 U2 - 10.1111/2041-210X.12301 DO - 10.1111/2041-210X.12301 M3 - Article VL - 6 SP - 198 EP - 208 JO - Methods in Ecology and Evolution JF - Methods in Ecology and Evolution SN - 2041-210X IS - 2 ER - TY - JOUR T1 - Non-destructive tree volume estimation through quantitative structure modelling T2 - Comparing UAV laser scanning with terrestrial LIDAR AU - Brede, Benjamin AU - Calders, Kim AU - Lau, Alvaro AU - Raumonen, Pasi AU - Bartholomeus, Harm M. AU - Herold, Martin AU - Kooistra, Lammert PY - 2019/11/1 Y1 - 2019/11/1 N2 - Above-Ground Biomass (AGB) product calibration and validation require ground reference plots at hectometric scales to match space-borne missions' resolution. Traditional forest inventory methods that use allometric equations for single tree AGB estimation suffer from biases and low accuracy, especially when dealing with large trees. Terrestrial Laser Scanning (TLS) and explicit tree modelling show high potential for direct estimates of tree volume, but at the cost of time demanding fieldwork. This study aimed to assess if novel Unmanned Aerial Vehicle Laser Scanning (UAV-LS) could overcome this limitation, while delivering comparable results. For this purpose, the performance of UAV-LS in comparison with TLS for explicit tree modelling was tested in a Dutch temperate forest. In total, 200 trees with Diameter at Breast Height (DBH) ranging from 6 to 91 cm from 5 stands, including coniferous and deciduous species, have been scanned, segmented and subsequently modelled with TreeQSM. TreeQSM is a method that builds explicit tree models from laser scanner point clouds. Direct comparison with TLS derived models showed that UAV-LS reliably modelled the volume of trunks and branches with diameter ≥30 cm in the mature beech and oak stand with Concordance Correlation Coefficient (CCC) of 0.85 and RMSE of1.12 m3. Including smaller branch volume led to a considerable overestimation and decrease in correspondence to CCC of 0.51 and increase in RMSE to 6.59 m3. Denser stands prevented sensing of trunks and further decreased CCC to 0.36 in the Norway spruce stand. Also small, young trees posed problems by preventing a proper depiction of the trunk circumference and decreased CCC to 0.01. This dependence on stand indicated a strong impact of canopy structure on the UAV-LS volume modelling capacity. Improved flight paths, repeated acquisition flights or alternative modelling strategies could improve UAV-LS modelling performance under these conditions. This study contributes to the use of UAV-LS for fast tree volume and AGB estimation on scales relevant for satellite AGB product calibration and validation. AB - Above-Ground Biomass (AGB) product calibration and validation require ground reference plots at hectometric scales to match space-borne missions' resolution. Traditional forest inventory methods that use allometric equations for single tree AGB estimation suffer from biases and low accuracy, especially when dealing with large trees. Terrestrial Laser Scanning (TLS) and explicit tree modelling show high potential for direct estimates of tree volume, but at the cost of time demanding fieldwork. This study aimed to assess if novel Unmanned Aerial Vehicle Laser Scanning (UAV-LS) could overcome this limitation, while delivering comparable results. For this purpose, the performance of UAV-LS in comparison with TLS for explicit tree modelling was tested in a Dutch temperate forest. In total, 200 trees with Diameter at Breast Height (DBH) ranging from 6 to 91 cm from 5 stands, including coniferous and deciduous species, have been scanned, segmented and subsequently modelled with TreeQSM. TreeQSM is a method that builds explicit tree models from laser scanner point clouds. Direct comparison with TLS derived models showed that UAV-LS reliably modelled the volume of trunks and branches with diameter ≥30 cm in the mature beech and oak stand with Concordance Correlation Coefficient (CCC) of 0.85 and RMSE of1.12 m3. Including smaller branch volume led to a considerable overestimation and decrease in correspondence to CCC of 0.51 and increase in RMSE to 6.59 m3. Denser stands prevented sensing of trunks and further decreased CCC to 0.36 in the Norway spruce stand. Also small, young trees posed problems by preventing a proper depiction of the trunk circumference and decreased CCC to 0.01. This dependence on stand indicated a strong impact of canopy structure on the UAV-LS volume modelling capacity. Improved flight paths, repeated acquisition flights or alternative modelling strategies could improve UAV-LS modelling performance under these conditions. This study contributes to the use of UAV-LS for fast tree volume and AGB estimation on scales relevant for satellite AGB product calibration and validation. KW - Above-Ground Biomass (AGB) KW - Forest KW - Laser scanning KW - Quantitative Structure Model (QSM) KW - UAV U2 - 10.1016/j.rse.2019.111355 DO - 10.1016/j.rse.2019.111355 M3 - Article VL - 233 JO - Remote Sensing of Environment JF - Remote Sensing of Environment SN - 0034-4257 M1 - 111355 ER - TY - JOUR T1 - Nonlinear iteration semigroups of fuzzy Cauchy problems AU - Kaleva, Osmo N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Elsevier BV North-Holland PY - 2012 Y1 - 2012 U2 - 10.1016/j.fss.2012.04.016 DO - 10.1016/j.fss.2012.04.016 M3 - Article VL - 209 SP - 104 EP - 110 JO - Fuzzy Sets and Systems JF - Fuzzy Sets and Systems SN - 0165-0114 ER - TY - JOUR T1 - NP-completeness results for partitioning a graph into total dominating sets AU - Koivisto, Mikko AU - Laakkonen, Petteri AU - Lauri, Juho PY - 2018/1/1 Y1 - 2018/1/1 N2 - A total domatic k-partition of a graph is a partition of its vertex set into k subsets such that each intersects the open neighborhood of each vertex. The maximum k for which a total domatic k-partition exists is known as the total domatic number of a graph G, denoted by dt(G). We extend considerably the known hardness results by showing it is[Formula presented]-complete to decide whether dt(G)≥3 where G is a bipartite planar graph of bounded maximum degree. Similarly, for every k≥3, it is[Formula presented]-complete to decide whether dt(G)≥k, where G is split or k-regular. In particular, these results complement recent combinatorial results regarding dt(G) on some of these graph classes by showing that the known results are, in a sense, best possible. Finally, for general n-vertex graphs, we show the problem is solvable in 2nnO(1) time, and derive even faster algorithms for special graph classes. AB - A total domatic k-partition of a graph is a partition of its vertex set into k subsets such that each intersects the open neighborhood of each vertex. The maximum k for which a total domatic k-partition exists is known as the total domatic number of a graph G, denoted by dt(G). We extend considerably the known hardness results by showing it is[Formula presented]-complete to decide whether dt(G)≥3 where G is a bipartite planar graph of bounded maximum degree. Similarly, for every k≥3, it is[Formula presented]-complete to decide whether dt(G)≥k, where G is split or k-regular. In particular, these results complement recent combinatorial results regarding dt(G) on some of these graph classes by showing that the known results are, in a sense, best possible. Finally, for general n-vertex graphs, we show the problem is solvable in 2nnO(1) time, and derive even faster algorithms for special graph classes. KW - Combinatorics KW - Computational complexity KW - Graph theory KW - Total domatic number U2 - 10.1016/j.tcs.2018.04.006 DO - 10.1016/j.tcs.2018.04.006 M3 - Article JO - Theoretical Computer Science JF - Theoretical Computer Science SN - 0304-3975 ER - TY - JOUR T1 - Old and New Algorithms for Minimal Coverability Sets AU - Valmari, Antti AU - Hansen, Henri N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-11-17

Publisher name: IOS Press PY - 2014 Y1 - 2014 U2 - 10.3233/FI-2014-1002 DO - 10.3233/FI-2014-1002 M3 - Article VL - 131 SP - 1 EP - 25 JO - Fundamenta Informaticae JF - Fundamenta Informaticae SN - 0169-2968 IS - 1 ER - TY - JOUR T1 - On Computational Complexity Reduction Methods for Kalman Filter Extensions AU - Raitoharju, Matti AU - Piche, Robert PY - 2019/10/7 Y1 - 2019/10/7 N2 - The Kalman filter and its extensions are used in a vast number of aerospace and navigation applications for nonlinear state estimation of time series. In the literature, different approaches have been proposed to exploit the structure of the state and measurement models to reduce the computational demand of the algorithms. In this tutorial, we survey existing code optimization methods and present them using unified notation that allows them to be used with various Kalman filter extensions. We develop the optimization methods to cover a wider range of models, show how different structural optimizations can be combined, and present new applications for the existing optimizations. Furthermore, we present an example that shows that the exploitation of the structure of the problem can lead to improved estimation accuracy while reducing the computational load. This tutorial is intended for persons who are familiar with Kalman filtering and want to get insights for reducing the computational demand of different Kalman filter extensions. AB - The Kalman filter and its extensions are used in a vast number of aerospace and navigation applications for nonlinear state estimation of time series. In the literature, different approaches have been proposed to exploit the structure of the state and measurement models to reduce the computational demand of the algorithms. In this tutorial, we survey existing code optimization methods and present them using unified notation that allows them to be used with various Kalman filter extensions. We develop the optimization methods to cover a wider range of models, show how different structural optimizations can be combined, and present new applications for the existing optimizations. Furthermore, we present an example that shows that the exploitation of the structure of the problem can lead to improved estimation accuracy while reducing the computational load. This tutorial is intended for persons who are familiar with Kalman filtering and want to get insights for reducing the computational demand of different Kalman filter extensions. U2 - 10.1109/MAES.2019.2927898 DO - 10.1109/MAES.2019.2927898 M3 - Article VL - 34 SP - 2 EP - 19 JO - IEEE Aerospace and Electronic Systems Magazine JF - IEEE Aerospace and Electronic Systems Magazine SN - 0885-8985 IS - 10 ER - TY - JOUR T1 - On constructibility and unconstructibility of LTS operators from other LTS operators AU - Valmari, Antti PY - 2015 Y1 - 2015 N2 - An LTS operator can be constructed from a set of LTS operators up to an equivalence if and only if there is an LTS expression that only contains operators from the set and whose result is equivalent to the result of the operator. In this publication this idea is made precise in the context where each LTS has an alphabet of its own and the operators may depend on the alphabets. Then the extent to which LTS operators are constructible is studied. Most, if not all, established LTS operators have the property that each trace of the result arises from the execution of no more than one trace of each of its argument LTSs, and similarly for infinite traces. All LTS operators that have this property and satisfy some other rather weak regularity properties can be constructed from parallel composition and hiding up to the equivalence that compares the alphabets, traces, and infinite traces of the LTSs. Furthermore, a collection of other miscellaneous constructibility and unconstructibility results is presented. AB - An LTS operator can be constructed from a set of LTS operators up to an equivalence if and only if there is an LTS expression that only contains operators from the set and whose result is equivalent to the result of the operator. In this publication this idea is made precise in the context where each LTS has an alphabet of its own and the operators may depend on the alphabets. Then the extent to which LTS operators are constructible is studied. Most, if not all, established LTS operators have the property that each trace of the result arises from the execution of no more than one trace of each of its argument LTSs, and similarly for infinite traces. All LTS operators that have this property and satisfy some other rather weak regularity properties can be constructed from parallel composition and hiding up to the equivalence that compares the alphabets, traces, and infinite traces of the LTSs. Furthermore, a collection of other miscellaneous constructibility and unconstructibility results is presented. U2 - 10.1007/s00236-015-0217-2 DO - 10.1007/s00236-015-0217-2 M3 - Article VL - 52 SP - 207 EP - 234 JO - Acta Informatica JF - Acta Informatica SN - 0001-5903 IS - 2-3 ER - TY - JOUR T1 - On finding rainbow and colorful paths AU - Kowalik, Łukasz AU - Lauri, Juho PY - 2016 Y1 - 2016 N2 - In the Colorful Path problem we are given a graph G=(V,E) and an arbitrary vertex coloring function c:V→[k]. The goal is to find a colorful path, i.e., a path on k vertices, that visits each color. This problem has been introduced in the classical work of Alon et al. (1995) [1], and the authors proposed a dynamic programming algorithm that runs in time 2knO(1) and uses O(2k) space. Since then the only progress obtained is reducing the space size to a polynomial at the cost of using randomization. In this work we show that a progress in time complexity is unlikely: if Colorful Path can be solved in time (2-ε)knO(1), then Set Cover admits a (2-ε')n(nm)O(1)-time algorithm. The same applies to other versions of the problem: when edges are colored instead of vertices, or we ask for a walk instead of a path, or when the requested path/walk has specified endpoints.We study also a second, very related problem. In Rainbow s t -Connectivity, we are given a k-edge-colored graph and two vertices s and t. The goal is to decide whether there is a rainbow path between s and t, that is, a path on which no color repeats. In its vertex variant (Rainbow Vertex s t -Connectivity) the input graph is k-vertex-colored, and a rainbow path is defined analogously. Uchizawa et al. (2011) [14] show that both variants can be solved in 2knO(1) time and exponential space. We show that the space size can be reduced to a polynomial, while keeping the same running time. In contrast to the polynomial space algorithm for Colorful Path, our algorithm for finding rainbow paths is deterministic. AB - In the Colorful Path problem we are given a graph G=(V,E) and an arbitrary vertex coloring function c:V→[k]. The goal is to find a colorful path, i.e., a path on k vertices, that visits each color. This problem has been introduced in the classical work of Alon et al. (1995) [1], and the authors proposed a dynamic programming algorithm that runs in time 2knO(1) and uses O(2k) space. Since then the only progress obtained is reducing the space size to a polynomial at the cost of using randomization. In this work we show that a progress in time complexity is unlikely: if Colorful Path can be solved in time (2-ε)knO(1), then Set Cover admits a (2-ε')n(nm)O(1)-time algorithm. The same applies to other versions of the problem: when edges are colored instead of vertices, or we ask for a walk instead of a path, or when the requested path/walk has specified endpoints.We study also a second, very related problem. In Rainbow s t -Connectivity, we are given a k-edge-colored graph and two vertices s and t. The goal is to decide whether there is a rainbow path between s and t, that is, a path on which no color repeats. In its vertex variant (Rainbow Vertex s t -Connectivity) the input graph is k-vertex-colored, and a rainbow path is defined analogously. Uchizawa et al. (2011) [14] show that both variants can be solved in 2knO(1) time and exponential space. We show that the space size can be reduced to a polynomial, while keeping the same running time. In contrast to the polynomial space algorithm for Colorful Path, our algorithm for finding rainbow paths is deterministic. U2 - 10.1016/j.tcs.2016.03.017 DO - 10.1016/j.tcs.2016.03.017 M3 - Article VL - 628 SP - 110 EP - 114 JO - Theoretical Computer Science JF - Theoretical Computer Science SN - 0304-3975 ER - TY - JOUR T1 - On Fractional Ornstein-Uhlenbeck Process AU - Kaarakka, Terhi AU - Salminen, Paavo N1 - ei ut-numeroa 22.3.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Article VL - 5 SP - 121 EP - 133 JO - Communications on Stochastic Analysis JF - Communications on Stochastic Analysis SN - 0973-9599 IS - 1 ER - TY - JOUR T1 - On homomorphisms between products of median algebras AU - Couceiro, Miguel AU - Foldes, Stephan AU - Meletiou, Gerasimos C. PY - 2017 Y1 - 2017 N2 - Homomorphisms of products of median algebras are studied with particular attention to the case when the codomain is a tree. In particular, we show that all mappings from a product (Formula presented.) of median algebras to a median algebra (Formula presented.) are essentially unary whenever the codomain (Formula presented.) is a tree. In view of this result, we also characterize trees as median algebras and semilattices by relaxing the defining conditions of conservative median algebras. AB - Homomorphisms of products of median algebras are studied with particular attention to the case when the codomain is a tree. In particular, we show that all mappings from a product (Formula presented.) of median algebras to a median algebra (Formula presented.) are essentially unary whenever the codomain (Formula presented.) is a tree. In view of this result, we also characterize trees as median algebras and semilattices by relaxing the defining conditions of conservative median algebras. U2 - 10.1007/s00012-017-0468-6 DO - 10.1007/s00012-017-0468-6 M3 - Article VL - 78 SP - 545 EP - 553 JO - Algebra Universalis JF - Algebra Universalis SN - 0002-5240 IS - 4 ER - TY - JOUR T1 - On hypermonogenic functions AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - Taylor&Francis Online first: Forthcoming articles 14.9.2011.Poistettu Portfolio13:sta tuplat r=1850 ja r=1851.

Contribution: organisation=mat,FACT1=1 PY - 2013 Y1 - 2013 U2 - 10.1080/17476933.2011.613118 DO - 10.1080/17476933.2011.613118 M3 - Article VL - 58 SP - 975 EP - 990 JO - Complex Variables and Elliptic Equations JF - Complex Variables and Elliptic Equations SN - 1747-6933 IS - 7 ER - TY - JOUR T1 - On k-Hypermonogenic Functions and Their Mean Value Properties AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki PY - 2016 Y1 - 2016 N2 - We study a hyperbolic version of holomorphic functions to higher dimensions. In this frame work, a generalization of holomorphic functions are called (Formula presented.)-hypermonogenic functions. These functions are depending on several real variables and their values are in a Clifford algebra. They are defined in terms of hyperbolic Dirac operators. They are connected to harmonic functions with respect to the Riemannian metric (Formula presented.) in the same way as the usual harmonic function to holomorphic functions. We present the mean value property for (Formula presented.)-hypermonogenic functions and related results. Earlier the mean value properties has been proved for hypermonogenic functions. The key tools are the invariance properties of the hyperbolic metric. AB - We study a hyperbolic version of holomorphic functions to higher dimensions. In this frame work, a generalization of holomorphic functions are called (Formula presented.)-hypermonogenic functions. These functions are depending on several real variables and their values are in a Clifford algebra. They are defined in terms of hyperbolic Dirac operators. They are connected to harmonic functions with respect to the Riemannian metric (Formula presented.) in the same way as the usual harmonic function to holomorphic functions. We present the mean value property for (Formula presented.)-hypermonogenic functions and related results. Earlier the mean value properties has been proved for hypermonogenic functions. The key tools are the invariance properties of the hyperbolic metric. KW - Dirac operator KW - Hyperbolic metric KW - Hypermonogenic KW - Monogenic U2 - 10.1007/s11785-015-0445-z DO - 10.1007/s11785-015-0445-z M3 - Article VL - 10 SP - 311 EP - 325 JO - Complex Analysis and Operator Theory JF - Complex Analysis and Operator Theory SN - 1661-8254 IS - 2 ER - TY - JOUR T1 - Online tests of Kalman filter consistency AU - Piché, Robert PY - 2016 Y1 - 2016 N2 - The normalised innovation squared (NIS) test, which is used to assess whether a Kalman filter's noise assumptions are consistent with realised measurements, can be applied online with real data, and does not require future data, repeated experiments or knowledge of the true state. In this work, it is shown that the NIS test is equivalent to three other model criticism procedures, which are as follows: (i) it can be derived as a Bayesian p-test for the prior predictive distribution; (ii) as a nested-model parameter significance test; and (iii) from a recently-proposed filter residual test. A new NIS-like test corresponding to a posterior predictive Bayesian p-test is presented. AB - The normalised innovation squared (NIS) test, which is used to assess whether a Kalman filter's noise assumptions are consistent with realised measurements, can be applied online with real data, and does not require future data, repeated experiments or knowledge of the true state. In this work, it is shown that the NIS test is equivalent to three other model criticism procedures, which are as follows: (i) it can be derived as a Bayesian p-test for the prior predictive distribution; (ii) as a nested-model parameter significance test; and (iii) from a recently-proposed filter residual test. A new NIS-like test corresponding to a posterior predictive Bayesian p-test is presented. KW - Kalman filter KW - Model consistency KW - Normalised innovations squared KW - Predictive distribution U2 - 10.1002/acs.2571 DO - 10.1002/acs.2571 M3 - Article VL - 30 SP - 115 EP - 124 JO - International Journal of Adaptive Control and Signal Processing JF - International Journal of Adaptive Control and Signal Processing SN - 0890-6327 IS - 1 ER - TY - JOUR T1 - On the complexity of rainbow coloring problems AU - Eiben, Eduard AU - Ganian, Robert AU - Lauri, Juho PY - 2018/9 Y1 - 2018/9 N2 - An edge-colored graph G is said to be rainbow connected if between each pair of vertices there exists a path which uses each color at most once. The rainbow connection number , denoted by rc(G), is the minimum number of colors needed to make G rainbow connected. Along with its variants, which consider vertex colorings and/or so-called strong colorings, the rainbow connection number has been studied from both the algorithmic and graph-theoretic points of view.In this paper we present a range of new results on the computational complexity of computing the four major variants of the rainbow connection number. In particular, we prove that the Strong Rainbow Vertex Coloring problem is View the MathML source-complete even on graphs of diameter 3, and also when the number of colors is restricted to 2. On the other hand, we show that if the number of colors is fixed then all of the considered problems can be solved in linear time on graphs of bounded treewidth. Moreover, we provide a linear-time algorithm which decides whether it is possible to obtain a rainbow coloring by saving a fixed number of colors from a trivial upper bound. Finally, we give a linear-time algorithm for computing the exact rainbow connection numbers for three variants of the problem on graphs of bounded vertex cover number. AB - An edge-colored graph G is said to be rainbow connected if between each pair of vertices there exists a path which uses each color at most once. The rainbow connection number , denoted by rc(G), is the minimum number of colors needed to make G rainbow connected. Along with its variants, which consider vertex colorings and/or so-called strong colorings, the rainbow connection number has been studied from both the algorithmic and graph-theoretic points of view.In this paper we present a range of new results on the computational complexity of computing the four major variants of the rainbow connection number. In particular, we prove that the Strong Rainbow Vertex Coloring problem is View the MathML source-complete even on graphs of diameter 3, and also when the number of colors is restricted to 2. On the other hand, we show that if the number of colors is fixed then all of the considered problems can be solved in linear time on graphs of bounded treewidth. Moreover, we provide a linear-time algorithm which decides whether it is possible to obtain a rainbow coloring by saving a fixed number of colors from a trivial upper bound. Finally, we give a linear-time algorithm for computing the exact rainbow connection numbers for three variants of the problem on graphs of bounded vertex cover number. U2 - 10.1016/j.dam.2016.10.021 DO - 10.1016/j.dam.2016.10.021 M3 - Article VL - 246 SP - 38 EP - 48 JO - Discrete Applied Mathematics JF - Discrete Applied Mathematics SN - 0166-218X ER - TY - JOUR T1 - On the complexity of restoring corrupted colorings AU - De Biasi, Marzio AU - Lauri, Juho PY - 2019/5 Y1 - 2019/5 N2 - In the r-Fix problem, we are given a graph G, a (non-proper) vertex-coloring c: V(G) → [r] , and a positive integer k. The goal is to decide whether a proper r-coloring c′ is obtainable from c by recoloring at most k vertices of G. Recently, Junosza-Szaniawski et al. (in: SOFSEM 2015: theory and practice of computer science, Springer, Berlin, 2015) asked whether the problem has a polynomial kernel parameterized by the number of recolorings k. In a full version of the manuscript, the authors together with Garnero and Montealegre, answered the question in the negative: for every r≥ 3 , the problem r-Fix does not admit a polynomial kernel unless [InlineEquation not available: see fulltext.]. Independently of their work, we give an alternative proof of the theorem. Furthermore, we study the complexity of r-Swap, where the only difference from r-Fix is that instead of k recolorings we have a budget of k color swaps. We show that for every r≥ 3 , the problem r-Swap is [InlineEquation not available: see fulltext.]-hard whereas r-Fix is known to be FPT. Moreover, when r is part of the input, we observe both Fix and Swap are [InlineEquation not available: see fulltext.]-hard parameterized by the treewidth of the input graph. We also study promise variants of the problems, where we are guaranteed that a proper r-coloring c′ is indeed obtainable from c by some finite number of swaps. For instance, we prove that for r= 3 , the problems r-Fix-Promise and r-Swap-Promise are [InlineEquation not available: see fulltext.]-hard for planar graphs. As a consequence of our reduction, the problems cannot be solved in 2o(n) time unless the Exponential Time Hypothesis fails. AB - In the r-Fix problem, we are given a graph G, a (non-proper) vertex-coloring c: V(G) → [r] , and a positive integer k. The goal is to decide whether a proper r-coloring c′ is obtainable from c by recoloring at most k vertices of G. Recently, Junosza-Szaniawski et al. (in: SOFSEM 2015: theory and practice of computer science, Springer, Berlin, 2015) asked whether the problem has a polynomial kernel parameterized by the number of recolorings k. In a full version of the manuscript, the authors together with Garnero and Montealegre, answered the question in the negative: for every r≥ 3 , the problem r-Fix does not admit a polynomial kernel unless [InlineEquation not available: see fulltext.]. Independently of their work, we give an alternative proof of the theorem. Furthermore, we study the complexity of r-Swap, where the only difference from r-Fix is that instead of k recolorings we have a budget of k color swaps. We show that for every r≥ 3 , the problem r-Swap is [InlineEquation not available: see fulltext.]-hard whereas r-Fix is known to be FPT. Moreover, when r is part of the input, we observe both Fix and Swap are [InlineEquation not available: see fulltext.]-hard parameterized by the treewidth of the input graph. We also study promise variants of the problems, where we are guaranteed that a proper r-coloring c′ is indeed obtainable from c by some finite number of swaps. For instance, we prove that for r= 3 , the problems r-Fix-Promise and r-Swap-Promise are [InlineEquation not available: see fulltext.]-hard for planar graphs. As a consequence of our reduction, the problems cannot be solved in 2o(n) time unless the Exponential Time Hypothesis fails. KW - Combinatorial reconfiguration KW - Computational complexity KW - Graph coloring KW - Local search KW - Parameterized complexity U2 - 10.1007/s10878-018-0342-2 DO - 10.1007/s10878-018-0342-2 M3 - Article VL - 37 SP - 1150 EP - 1169 JO - Journal of Combinatorial Optimization JF - Journal of Combinatorial Optimization SN - 1382-6905 IS - 4 ER - TY - JOUR T1 - On the Discrete-Time Regulator Problem in Infinite-Dimensional Spaces AU - Pohjolainen, S. A. PY - 1980 Y1 - 1980 N2 - The linear, discrete-time regulator problem is considered in infinite-dimensional spaces without posing in advance any positivity conditions on quadratic criterion. The convergence of the finite-time optimum solution is studied, when time increases to infinity with a stable, stabilizable, and detectable system. AB - The linear, discrete-time regulator problem is considered in infinite-dimensional spaces without posing in advance any positivity conditions on quadratic criterion. The convergence of the finite-time optimum solution is studied, when time increases to infinity with a stable, stabilizable, and detectable system. U2 - 10.1007/BF00934502 DO - 10.1007/BF00934502 M3 - Article VL - 30 SP - 319 EP - 327 JO - Journal of Optimization Theory and Applications JF - Journal of Optimization Theory and Applications SN - 0022-3239 IS - 2 ER - TY - JOUR T1 - On the distribution of coefficients of powers of positive polynomials AU - Major, Lazlo N1 - ei ut-numeroa 5.4.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Article VL - 49 SP - 239 EP - 243 JO - Australasian Journal of Combinatorics JF - Australasian Journal of Combinatorics SN - 1034-4942 ER - TY - JOUR T1 - On the fine-grained complexity of rainbow coloring AU - Kowalik, Lukasz AU - Lauri, Juho AU - La, Arkadiusz Soca PY - 2018 Y1 - 2018 N2 - The Rainbow k-Coloring problem asks whether the edges of a given graph can be colored in k colors so that every pair of vertices is connected by a rainbow path, i.e., a path with all edges of different colors. Our main result states that for any k ≥ 2, there is no algorithm for Rainbow k-Coloring running in time 2o(n 3/2), unless the exponential time hypothesis fails. Motivated by this negative result we consider two parameterized variants of the problem. In the Subset Rainbow k-Coloring problem, introduced by Chakraborty et al. [J. Comb. Optim., 21 (2009), pp. 330-347], we are additionally given a set S of pairs of vertices and we ask if there is a coloring in which all the pairs in S are connected by rainbow paths. We show that Subset Rainbow k-Coloring is fixed parameter tractable (FPT) when parameterized by |S|. We also study the Maximum Rainbow k-Coloring problem, where we are additionally given an integer q, and we ask if there is a coloring in which at least q anti-edges are connected by rainbow paths. We show that the problem is FPT when parameterized by q and has a kernel of size O(q) for every k ≥ 2, extending the result of Ananth, Nasre, and Sarpatwar, in FSTTCS, LIPIcs, Schloss Dagstuhl-Leibniz-Zentum für Informatik, Dagstuhl, Germany, 2011, pp. 241-251. We believe that our techniques used for the lower bounds may shed some light on the complexity of the classical Edge Coloring problem, where it is a major open question if a 2O(n)-time algorithm exists. AB - The Rainbow k-Coloring problem asks whether the edges of a given graph can be colored in k colors so that every pair of vertices is connected by a rainbow path, i.e., a path with all edges of different colors. Our main result states that for any k ≥ 2, there is no algorithm for Rainbow k-Coloring running in time 2o(n 3/2), unless the exponential time hypothesis fails. Motivated by this negative result we consider two parameterized variants of the problem. In the Subset Rainbow k-Coloring problem, introduced by Chakraborty et al. [J. Comb. Optim., 21 (2009), pp. 330-347], we are additionally given a set S of pairs of vertices and we ask if there is a coloring in which all the pairs in S are connected by rainbow paths. We show that Subset Rainbow k-Coloring is fixed parameter tractable (FPT) when parameterized by |S|. We also study the Maximum Rainbow k-Coloring problem, where we are additionally given an integer q, and we ask if there is a coloring in which at least q anti-edges are connected by rainbow paths. We show that the problem is FPT when parameterized by q and has a kernel of size O(q) for every k ≥ 2, extending the result of Ananth, Nasre, and Sarpatwar, in FSTTCS, LIPIcs, Schloss Dagstuhl-Leibniz-Zentum für Informatik, Dagstuhl, Germany, 2011, pp. 241-251. We believe that our techniques used for the lower bounds may shed some light on the complexity of the classical Edge Coloring problem, where it is a major open question if a 2O(n)-time algorithm exists. KW - Computational complexity KW - FPT algorithms KW - Graph coloring KW - Lower bounds U2 - 10.1137/16M1102690 DO - 10.1137/16M1102690 M3 - Article VL - 32 SP - 1672 EP - 1705 JO - SIAM Journal on Discrete Mathematics JF - SIAM Journal on Discrete Mathematics SN - 0895-4801 IS - 3 ER - TY - JOUR T1 - On the spectral and Frobenius norm of a generalized Fibonacci r-circulant matrix AU - Merikoski, Jorma K. AU - Haukkanen, Pentti AU - Mattila, Mika AU - Tossavainen, Timo PY - 2018/1/1 Y1 - 2018/1/1 N2 - Consider the recursion g0 = a, g1 = b, gn = gn-1 + gn-2, n = 2, 3, . . . . We compute the Frobenius norm of the r-circulant matrix corresponding to g0, . . . , gn-1. We also give three lower bounds (with equality conditions) for the spectral norm of this matrix. For this purpose, we present three ways to estimate the spectral norm from below in general. AB - Consider the recursion g0 = a, g1 = b, gn = gn-1 + gn-2, n = 2, 3, . . . . We compute the Frobenius norm of the r-circulant matrix corresponding to g0, . . . , gn-1. We also give three lower bounds (with equality conditions) for the spectral norm of this matrix. For this purpose, we present three ways to estimate the spectral norm from below in general. KW - Euclidean norm KW - Frobenius norm KW - generalized Fibonacci numbers KW - r-circulant matrix KW - spectral norm U2 - 10.1515/spma-2018-0003 DO - 10.1515/spma-2018-0003 M3 - Article VL - 6 SP - 23 EP - 36 JO - Special Matrices JF - Special Matrices SN - 2300-7451 IS - 1 ER - TY - JOUR T1 - On the Structure of Octonion Regular Functions AU - Kauhanen, Janne AU - Orelma, Heikki PY - 2019/9 Y1 - 2019/9 N2 - In this paper, we study octonion regular functions and the structural differences between regular functions in octonion, quaternion, and Clifford analyses. AB - In this paper, we study octonion regular functions and the structural differences between regular functions in octonion, quaternion, and Clifford analyses. U2 - 10.1007/s00006-019-0983-y DO - 10.1007/s00006-019-0983-y M3 - Article VL - 29 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 4 M1 - 77 ER - TY - JOUR T1 - On the Succinctness of Atoms of Dependency AU - Vilander, Miikka AU - Lück, Martin PY - 2019/8/20 Y1 - 2019/8/20 N2 - Propositional team logic is the propositional analog to first-order team logic. Non-classical atoms of dependence, independence, inclusion, exclusion and anonymity can be expressed in it, but for all atoms except dependence only exponential translations are known. In this paper, we systematically compare their succinctness in the existential fragment, where the splitting disjunction only occurs positively, and in full propositional team logic with unrestricted negation. By introducing a variant of the Ehrenfeucht-Fra\"{i}ssé game called formula size game into team logic, we obtain exponential lower bounds in the existential fragment for all atoms. In the full fragment, we present polynomial upper bounds also for all atoms. AB - Propositional team logic is the propositional analog to first-order team logic. Non-classical atoms of dependence, independence, inclusion, exclusion and anonymity can be expressed in it, but for all atoms except dependence only exponential translations are known. In this paper, we systematically compare their succinctness in the existential fragment, where the splitting disjunction only occurs positively, and in full propositional team logic with unrestricted negation. By introducing a variant of the Ehrenfeucht-Fra\"{i}ssé game called formula size game into team logic, we obtain exponential lower bounds in the existential fragment for all atoms. In the full fragment, we present polynomial upper bounds also for all atoms. KW - team semantics KW - succinctness KW - dependence atom M3 - Article VL - 15 SP - 17:1-17:28 JO - Logical Methods in Computer Science JF - Logical Methods in Computer Science SN - 1860-5974 IS - 3 ER - TY - JOUR T1 - On the Underlying Mathematical and Quantum Structure of Quantum Cryptography AU - Gotkhindikar, Ajey Dilip PY - 2016/2 Y1 - 2016/2 N2 - Quantum cryptography is a novel approach to provide secure communication, based on the laws of physics. It offers perfect security for the communication between two authorized parties, while assuming very high computational capacity for the eavesdropper, who may be attempting to intrude into this communication. It provides a very high rate of intrusion detection as against the classical systems. Classical cryptography is built on a fundamental assumption that it is difficult to invert some of mathematical functions, in a limited time, with the use of efficient computing resources. While, quantum cryptography is based on formidable laws of nature, making it less prone to attack. With the advent of quantum computing, boundaries between various subjects like quantum physics, computer science and mathematics are getting reduced. In the early seventies, Steven Wiesner made pioneering efforts in the field Quantum Cryptography. In its present form, Quantum Cryptography depends on two essential principles of Quantum Mechanics. One is that no information is available without causing disturbance in the system and other is Principle of No-Cloning. In this paper we present some of fundamental aspects of Quantum Cryptography and the underlying structures that makes it a credible option for providing perfect security of information. AB - Quantum cryptography is a novel approach to provide secure communication, based on the laws of physics. It offers perfect security for the communication between two authorized parties, while assuming very high computational capacity for the eavesdropper, who may be attempting to intrude into this communication. It provides a very high rate of intrusion detection as against the classical systems. Classical cryptography is built on a fundamental assumption that it is difficult to invert some of mathematical functions, in a limited time, with the use of efficient computing resources. While, quantum cryptography is based on formidable laws of nature, making it less prone to attack. With the advent of quantum computing, boundaries between various subjects like quantum physics, computer science and mathematics are getting reduced. In the early seventies, Steven Wiesner made pioneering efforts in the field Quantum Cryptography. In its present form, Quantum Cryptography depends on two essential principles of Quantum Mechanics. One is that no information is available without causing disturbance in the system and other is Principle of No-Cloning. In this paper we present some of fundamental aspects of Quantum Cryptography and the underlying structures that makes it a credible option for providing perfect security of information. U2 - 10.18535/ijecs/v5i2.7 DO - 10.18535/ijecs/v5i2.7 M3 - Article VL - 5 SP - 15685 EP - 15699 JO - International Journal of Engineering and Computer Science JF - International Journal of Engineering and Computer Science SN - 2319-7242 IS - 2 ER - TY - JOUR T1 - On Vekua Systems and Their Connections to Hyperbolic Function Theory in the Plane AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2015-01-14

Publisher name: Birkhaeuser Science PY - 2014 Y1 - 2014 U2 - 10.1007/s00006-014-0507-8 DO - 10.1007/s00006-014-0507-8 M3 - Article VL - 24 SP - 1027 EP - 1038 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 4 ER - TY - JOUR T1 - Optical properties of snow in backscatter AU - Kaasalainen, S. AU - Kaasalainen, M. AU - Mielonen, T. AU - Suomalainen, J. AU - Peltoniemi, J. AU - Näränen, J. N1 - Contribution: organisation=mat,FACT1=1 PY - 2006 Y1 - 2006 M3 - Article VL - 52 SP - 574 EP - 584 JO - Journal of Glaciology JF - Journal of Glaciology SN - 0022-1430 IS - 179 ER - TY - JOUR T1 - Optimal computation of brightness integrals parametrized on the unit sphere AU - Kaasalainen, Mikko AU - Lu, X. AU - Vänttinen, A.-V. N1 - Contribution: organisation=mat,FACT1=1

Publisher name: EDP Sciences PY - 2012 Y1 - 2012 U2 - 10.1051/0004-6361/201117982 DO - 10.1051/0004-6361/201117982 M3 - Article VL - 539 SP - 7 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A96 ER - TY - JOUR T1 - Optimal energy decay for the wave-heat system on a rectangular domain AU - Batty, Charles AU - Paunonen, Lassi AU - Seifert, David PY - 2019 Y1 - 2019 N2 - We study the rate of energy decay for solutions of a coupled wave-heat system on a rectangular domain. Using techniques from the theory of C 0 -semigroups, and in particular a well-known result due to Borichev and Tomilov, we prove that the energy of classical solutions decays like t - 2/ 3 as t \rightarrow \infty . This rate is moreover shown to be sharp. Our result implies in particular that a general estimate in the literature, which predicts at least logarithmic decay and is known to be best possible in general, is suboptimal in the special case under consideration here. Our strategy of proof involves direct estimates based on separation of variables and a refined version of the technique developed in our earlier paper for a one-dimensional wave-heat system. AB - We study the rate of energy decay for solutions of a coupled wave-heat system on a rectangular domain. Using techniques from the theory of C 0 -semigroups, and in particular a well-known result due to Borichev and Tomilov, we prove that the energy of classical solutions decays like t - 2/ 3 as t \rightarrow \infty . This rate is moreover shown to be sharp. Our result implies in particular that a general estimate in the literature, which predicts at least logarithmic decay and is known to be best possible in general, is suboptimal in the special case under consideration here. Our strategy of proof involves direct estimates based on separation of variables and a refined version of the technique developed in our earlier paper for a one-dimensional wave-heat system. KW - C -semigroups KW - Coupled KW - Energy KW - Heat equation KW - Rates of decay KW - Rectangular domain KW - Resolvent estimates KW - Wave equation U2 - 10.1137/18M1195796 DO - 10.1137/18M1195796 M3 - Article VL - 51 SP - 808 EP - 819 JO - SIAM JOURNAL ON MATHEMATICAL ANALYSIS JF - SIAM JOURNAL ON MATHEMATICAL ANALYSIS SN - 0036-1410 IS - 2 ER - TY - JOUR T1 - Optimal energy decay in a one-dimensional coupled wave–heat system AU - Batty, Charles AU - Paunonen, Lassi AU - Seifert, David PY - 2016/9 Y1 - 2016/9 N2 - We study a simple one-dimensional coupled wave–heat system and obtain a sharp estimate for the rate of energy decay of classical solutions. Our approach is based on the asymptotic theory of C0-semigroups and in particular on a result due to Borichev and Tomilov (Math Ann 347:455–478, 2010), which reduces the problem of estimating the rate of energy decay to finding a growth bound for the resolvent of the semigroup generator. This technique not only leads to an optimal result, it is also simpler than the methods used by other authors in similar situations. AB - We study a simple one-dimensional coupled wave–heat system and obtain a sharp estimate for the rate of energy decay of classical solutions. Our approach is based on the asymptotic theory of C0-semigroups and in particular on a result due to Borichev and Tomilov (Math Ann 347:455–478, 2010), which reduces the problem of estimating the rate of energy decay to finding a growth bound for the resolvent of the semigroup generator. This technique not only leads to an optimal result, it is also simpler than the methods used by other authors in similar situations. KW - C-semigroups KW - Coupled KW - Energy KW - Heat equation KW - Rates of decay KW - Resolvent estimates KW - Wave equation U2 - 10.1007/s00028-015-0316-0 DO - 10.1007/s00028-015-0316-0 M3 - Article VL - 16 SP - 649 EP - 664 JO - Journal of Evolution Equations JF - Journal of Evolution Equations SN - 1424-3199 IS - 3 ER - TY - JOUR T1 - Optimization of large-area OLED current distribution grids with self-aligned passivation AU - Janka, M. AU - Saukko, E. AU - Raumonen, P. AU - Lupo, D. N1 - Contribution: organisation=elt,FACT1=0.8

Contribution: organisation=fys,FACT2=0.1

Contribution: organisation=mat,FACT3=0.1

Portfolio EDEND: 2014-11-11

Publisher name: Elsevier BV PY - 2014 Y1 - 2014 U2 - 10.1016/j.orgel.2014.09.028 DO - 10.1016/j.orgel.2014.09.028 M3 - Article VL - 15 SP - 3431 EP - 3438 JO - Organic Electronics JF - Organic Electronics SN - 1566-1199 IS - 12 ER - TY - JOUR T1 - Orbiter-to-orbiter tomography T2 - a potential approach for small solar system bodies AU - Pursiainen, Sampsa AU - Kaasalainen, Mikko PY - 2016 Y1 - 2016 N2 - The goal of this paper is to advance mathematical and computational methodology for orbiter-to-orbiter radio tomography of small solar system bodies. In this study, an advanced full waveform forward model is coupled with a total variation-based inversion technique. We use a satellite formation model in which a single unit receives a signal that is transmitted by one or more transponder satellites. Numerical results for a two-dimensional domain are presented. AB - The goal of this paper is to advance mathematical and computational methodology for orbiter-to-orbiter radio tomography of small solar system bodies. In this study, an advanced full waveform forward model is coupled with a total variation-based inversion technique. We use a satellite formation model in which a single unit receives a signal that is transmitted by one or more transponder satellites. Numerical results for a two-dimensional domain are presented. U2 - 10.1109/TAES.2016.150638 DO - 10.1109/TAES.2016.150638 M3 - Article VL - 52 SP - 2747 EP - 2759 JO - IEEE Transactions on Aerospace and Electronic Systems JF - IEEE Transactions on Aerospace and Electronic Systems SN - 0018-9251 IS - 6 ER - TY - JOUR T1 - Paraconsistent Many-Valued Logic in GUHA Framework AU - Turunen, Esko PY - 2018/5/3 Y1 - 2018/5/3 N2 - The primary aim of this paper is to establish a formal connection between a particular many-valued paraconsistent logic and the logic of a KDD method, namely the GUHA data mining method by introducing a new quantifier called Paraconsistent Separation quantifier. This quantifier is implemented to LISp-Miner Software. The secondary aim is to demonstrate a possible usefulness of this quantifier in social and other applied sciences by examples taking from family planning context. AB - The primary aim of this paper is to establish a formal connection between a particular many-valued paraconsistent logic and the logic of a KDD method, namely the GUHA data mining method by introducing a new quantifier called Paraconsistent Separation quantifier. This quantifier is implemented to LISp-Miner Software. The secondary aim is to demonstrate a possible usefulness of this quantifier in social and other applied sciences by examples taking from family planning context. U2 - 10.18267/j.aip.116 DO - 10.18267/j.aip.116 M3 - Article VL - 7 SP - 104 EP - 111 JO - Acta Informatica Pragensia, University of Economics, Prague JF - Acta Informatica Pragensia, University of Economics, Prague SN - 1805-4951 IS - 1 ER - TY - JOUR T1 - Paraconsistent semantics for Pavelka style fuzzy sentential logic AU - Turunen, Esko AU - Özturkb, M. AU - Tsoukisc, A. N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1016/j.fss.2009.12.017 DO - 10.1016/j.fss.2009.12.017 M3 - Article VL - 161 SP - 1926 EP - 1940 JO - Fuzzy Sets and Systems JF - Fuzzy Sets and Systems SN - 0165-0114 IS - 14 ER - TY - JOUR T1 - Partitioned Update Kalman Filter AU - Raitoharju, Matti AU - Piché, Robert AU - Ala-Luhtala, Juha AU - Ali-Löytty, Simo N1 - ORG=ase,0.75 ORG=mat,0.25 PY - 2016/6 Y1 - 2016/6 N2 - In this paper we present a new Kalman filter extension for state update called Partitioned Update Kalman Filter (PUKF). PUKF updates state using multidimensional measurements in parts. PUKF evaluates the nonlinearity of the measurement function within Gaussian prior by comparing the innovation covariance caused by the second order linearization to the Gaussian measurement noise. A linear transformation is applied to measurements to minimize the nonlinearity of a part of the measurement. The measurement update is applied then using only the part of the measurement that has low nonlinearity and the process is then repeated for the updated state using the remaining part of the transformed measurement until the whole measurement has been used. PUKF does the linearizations numerically and no analytical differentiation is required. Results show that when measurement geometry allows effective partitioning, the proposed algorithm improves estimation accuracy and produces accurate covariance estimates. AB - In this paper we present a new Kalman filter extension for state update called Partitioned Update Kalman Filter (PUKF). PUKF updates state using multidimensional measurements in parts. PUKF evaluates the nonlinearity of the measurement function within Gaussian prior by comparing the innovation covariance caused by the second order linearization to the Gaussian measurement noise. A linear transformation is applied to measurements to minimize the nonlinearity of a part of the measurement. The measurement update is applied then using only the part of the measurement that has low nonlinearity and the process is then repeated for the updated state using the remaining part of the transformed measurement until the whole measurement has been used. PUKF does the linearizations numerically and no analytical differentiation is required. Results show that when measurement geometry allows effective partitioning, the proposed algorithm improves estimation accuracy and produces accurate covariance estimates. KW - math.OC KW - math.PR M3 - Article VL - 11 SP - 3 EP - 14 JO - Journal of Advances in Information Fusion JF - Journal of Advances in Information Fusion SN - 1557-6418 IS - 1 ER - TY - JOUR T1 - Pedagogical experiments with MathCheck in university teaching AU - Kaarakka, Terhi AU - Helkala, Kirsi AU - Valmari, Antti AU - Joutsenlahti, Marjukka PY - 2019/12/16 Y1 - 2019/12/16 N2 - MathCheck is a relatively new online tool that gives students feedback on their solutions to elementary university mathematics and theoretical computer science exercises. MathCheck was designed with constructivism learning theory in mind and it differs from other online tools as it checks the solutions step by step and shows a counter-example if the step is incorrect. It has been in student use since the autumn of 2015 and under design-based research from the first online day. The main research questions of this study are the following. 1) How can the usage of MathCheck support the aspects of conceptual understanding and procedural fluency of constructivism learning? 2) How can MathCheck empower both students and teachers in the education of mathematics? This paper presents the results of five pedagogical experiments considering both students’ and teachers’ point of views. In each experiment, the students have suggested improvements, which have affected the further development of MathCheck. In general, both students and teachers have given positive feedback on MathCheck. MathCheck seems to support learning better than tools that only provide the “incorrect”/“correct” verdict after checking the answer. MathCheck is suitable for independent studying as well as an addition to traditional lectures. In the best case, it can reduce teachers’ workload during courses. AB - MathCheck is a relatively new online tool that gives students feedback on their solutions to elementary university mathematics and theoretical computer science exercises. MathCheck was designed with constructivism learning theory in mind and it differs from other online tools as it checks the solutions step by step and shows a counter-example if the step is incorrect. It has been in student use since the autumn of 2015 and under design-based research from the first online day. The main research questions of this study are the following. 1) How can the usage of MathCheck support the aspects of conceptual understanding and procedural fluency of constructivism learning? 2) How can MathCheck empower both students and teachers in the education of mathematics? This paper presents the results of five pedagogical experiments considering both students’ and teachers’ point of views. In each experiment, the students have suggested improvements, which have affected the further development of MathCheck. In general, both students and teachers have given positive feedback on MathCheck. MathCheck seems to support learning better than tools that only provide the “incorrect”/“correct” verdict after checking the answer. MathCheck is suitable for independent studying as well as an addition to traditional lectures. In the best case, it can reduce teachers’ workload during courses. KW - Education KW - MathCheck KW - Mathematics KW - Pedagogy U2 - 10.31129/LUMAT.7.3.428 DO - 10.31129/LUMAT.7.3.428 M3 - Article VL - 7 SP - 84 EP - 112 JO - Lumat JF - Lumat SN - 2323-7112 IS - 3 ER - TY - JOUR T1 - Perfect Pavelka Logic AU - Turunen, Esko AU - Navara, Mirko N1 - In Press.Siirretään Portfolio15

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2015-01-08

Publisher name: Elsevier BV PY - 2015 Y1 - 2015 U2 - 10.1016/j.fss.2014.06.011 DO - 10.1016/j.fss.2014.06.011 M3 - Article JO - Fuzzy Sets and Systems JF - Fuzzy Sets and Systems SN - 0165-0114 ER - TY - JOUR T1 - Periodic Output Regulation for Distributed Parameter Systems AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Springer UK PY - 2012 Y1 - 2012 N2 - In this paper the output regulation of a linear distributed parameter system with a nonautonomous periodic exosystem is considered. It is shown that the solvability of the output regulation problem can be characterized by the solvability of a certain constrained infinite-dimensional Sylvester differential equation. Conditions are given for the existence of feedforward and feedback controllers solving the regulation problem along with a method for their construction. The theoretical results are applied to output regulation of a controlled delay equation. AB - In this paper the output regulation of a linear distributed parameter system with a nonautonomous periodic exosystem is considered. It is shown that the solvability of the output regulation problem can be characterized by the solvability of a certain constrained infinite-dimensional Sylvester differential equation. Conditions are given for the existence of feedforward and feedback controllers solving the regulation problem along with a method for their construction. The theoretical results are applied to output regulation of a controlled delay equation. U2 - 10.1007/s00498-012-0087-x DO - 10.1007/s00498-012-0087-x M3 - Article VL - 24 SP - 403 EP - 441 JO - Mathematics of Control Signals and Systems JF - Mathematics of Control Signals and Systems SN - 0932-4194 IS - 4 ER - TY - JOUR T1 - Perturbation of strongly and polynomially stable Riesz-spectral operators AU - Paunonen, Lassi N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 N2 - In this paper we consider bounded and relatively bounded finite rank perturbations of a Riesz-spectral operator generating a polynomially stable semigroup of linear operators on a Hilbert space. We concentrate on a commonly encountered situation where the spectrum of the unperturbed operator is contained in the open left half-plane of the complex plane and approaches the imaginary axis asymptotically. We present conditions on the perturbing operator such that the spectrum of the perturbed operator is contained in the open left half-plane of the complex plane and additional conditions for the strong and polynomial stabilities of the perturbed semigroup. We consider two applications of the perturbation results. In the first example we apply the results to the perturbation of a polynomially stabilized one-dimensional wave equation. In the second example we consider perturbation of a closed-loop system consisting of a distributed parameter system and an observer-based feedback controller solving the robust output regulation problem related to an infinite-dimensional signal generator. AB - In this paper we consider bounded and relatively bounded finite rank perturbations of a Riesz-spectral operator generating a polynomially stable semigroup of linear operators on a Hilbert space. We concentrate on a commonly encountered situation where the spectrum of the unperturbed operator is contained in the open left half-plane of the complex plane and approaches the imaginary axis asymptotically. We present conditions on the perturbing operator such that the spectrum of the perturbed operator is contained in the open left half-plane of the complex plane and additional conditions for the strong and polynomial stabilities of the perturbed semigroup. We consider two applications of the perturbation results. In the first example we apply the results to the perturbation of a polynomially stabilized one-dimensional wave equation. In the second example we consider perturbation of a closed-loop system consisting of a distributed parameter system and an observer-based feedback controller solving the robust output regulation problem related to an infinite-dimensional signal generator. U2 - 10.1016/j.sysconle.2011.01.005 DO - 10.1016/j.sysconle.2011.01.005 M3 - Article VL - 60 SP - 234 EP - 248 JO - Systems and Control Letters JF - Systems and Control Letters SN - 0167-6911 IS - 4 ER - TY - JOUR T1 - Photometry and models of selected main-belt asteroids (II) AU - Michalowski, T. AU - Kaasalainen, M. AU - Marciniak, A. AU - Denchev, P. AU - Kwiatkowski, T. AU - Kryszczynska, A. AU - Hirsch, R. AU - Velichko, F.P. AU - Erikson, A. AU - Szabo, Gy.M. AU - Kowalski, R. N1 - Contribution: organisation=mat,FACT1=1 PY - 2005 Y1 - 2005 U2 - 10.1051/0004-6361:20053656 DO - 10.1051/0004-6361:20053656 M3 - Article VL - 443 SP - 329 EP - 335 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - 1 ER - TY - JOUR T1 - Photometry and models of selected main-belt asteroids. III AU - Michalowski, T. AU - Kaasalainen, M. AU - Polinska, M. AU - Marciniak, A. AU - Kwiatkowski, A. AU - Kryszczynska, A. AU - Velichko, F.P. N1 - Contribution: organisation=mat,FACT1=1 PY - 2006 Y1 - 2006 U2 - 10.1051/0004-6361:20065877 DO - 10.1051/0004-6361:20065877 M3 - Article VL - 459 SP - 663 EP - 668 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 ER - TY - JOUR T1 - Photometry and models of selected main-belt asteroids. IV AU - Marciniak, A. AU - Michalowski, T. AU - Kaasalainen, M. AU - Durech, J. AU - Polinska, M. AU - Kwiatkowski, T. AU - Kryszczynska, A. AU - Hirsch, R. AU - Kaminski, K. AU - Fagas, M. AU - Colas, F. AU - Fauvaud, S. AU - Santacana, G. AU - Behrend, R. AU - Ro, R. N1 - Contribution: organisation=mat,FACT1=1 PY - 2007 Y1 - 2007 U2 - 10.1051/0004-6361:20077694 DO - 10.1051/0004-6361:20077694 M3 - Article VL - 473 SP - 633 EP - 639 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 ER - TY - JOUR T1 - Photometry and models of selected main-belt asteroids. V. AU - Marciniak, A. AU - Michalowski, T. AU - Kaasalainen, M. AU - Kryszczynska, A. AU - Kwiatkowski, T. AU - Hirsch, R. AU - Kaminski, K. AU - Fagas, M. AU - Polinska, M. AU - Velichko, F.P. AU - Michalowski, M.J. AU - Snodgrass, C. AU - Behrend, R. AU - Bernasconi, L. N1 - Contribution: organisation=mat,FACT1=1 PY - 2008 Y1 - 2008 U2 - 10.1051/0004-6361:20078930 DO - 10.1051/0004-6361:20078930 M3 - Article VL - 478 SP - 559 EP - 565 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - 2 ER - TY - JOUR T1 - Physical models of ten asteroids from an observers' collaboration network AU - Durech, J. AU - Kaasalainen, M. AU - Marciniak, A. AU - Allen, W.H. AU - Behrend, R. AU - Bembrick, C. AU - Bennett, T. AU - Bernasconi, L. AU - Berthier, J. AU - Bolt, G. AU - Boroumand, S. AU - Crespo da Silva, L. AU - Crippa, R. AU - Crow, M. AU - Durkee, R. AU - Dymock, R. AU - Fagas, M. AU - Fauerbach, M. AU - Fauvad, S. AU - Frey, M. N1 - Contribution: organisation=mat,FACT1=1 PY - 2006 Y1 - 2006 U2 - 10.1051/0004-6361:20066347 DO - 10.1051/0004-6361:20066347 M3 - Article VL - 465 SP - 331 EP - 337 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - 1 ER - TY - JOUR T1 - Physical properties of 2 Pallas AU - Carry, Benoit AU - Dumas, Christophe AU - Kaasalainen, Mikko AU - Berthier, Jerome AU - Merline, William J. AU - Erard, Stephane AU - Conrad, Al AU - Drummondg, Jack D. AU - Hestroffer, Daniel AU - Fulchignoni, Marcello AU - Fusco, Thierry N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1016/j.icarus.2009.08.007 DO - 10.1016/j.icarus.2009.08.007 M3 - Article VL - 205 SP - 460 EP - 472 JO - Icarus JF - Icarus SN - 0019-1035 IS - 2 ER - TY - JOUR T1 - Physical properties of the ESA ROsetta target asteroid (21) Lutetia. II. Shape and flyby geometry AU - Carry, B. AU - Kaasalainen, Mikko AU - Leyrat, C. AU - Merline, W.J. AU - Drummond, J.D. AU - Conrad, A. AU - Weaver, H.A. AU - Tamblyn, P.M. AU - Chapman, C.R. AU - Dumas, C. AU - Colas, F. AU - Christou, J.C. AU - Dotto, E. AU - Perna, D. AU - Fornasier, S. AU - Bernasconi, L. AU - Behrend, R. AU - Vachier, F. AU - Kryszczynska, A. AU - Polinska, M. AU - Fulchignoni, M. AU - Roy, R. AU - Naves, R. AU - Poncy, R. AU - Wiggins, P. N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1051/0004-6361/201015074 DO - 10.1051/0004-6361/201015074 M3 - Article VL - 523 SP - 1 EP - 19 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - A94 ER - TY - JOUR T1 - Planning the Schedule for the Disposal of the Spent Nuclear Fuel with Interactive Multiobjective Optimization AU - Montonen, Outi AU - Ranta, Timo AU - Makela, Marko M. PY - 2019/11/25 Y1 - 2019/11/25 N2 - Several countries utilize nuclear power and face the problem of what to do with the spent nuclear fuel. One possibility, which is under the scope in this paper, is to dispose of the fuel assemblies in the disposal facility. Before the assemblies can be disposed of, they must cool down their decay heat power in the interim storage. Next, they are loaded into canisters in the encapsulation facility, and finally, the canisters are placed in the disposal facility. In this paper, we model this process as a nonsmooth multiobjective mixed-integer nonlinear optimization problem with the minimization of nine objectives: the maximum number of assemblies in the storage, maximum storage time, average storage time, total number of canisters, end time of the encapsulation, operation time of the encapsulation facility, the lengths of disposal and central tunnels, and total costs. As a result, we obtain the disposal schedule i.e., amount of canisters disposed of periodically. We introduce the interactive multiobjective optimization method using the two-slope parameterized achievement scalarizing functions which enables us to obtain systematically several different Pareto optimal solutions from the same preference information. Finally, a case study adapting the disposal in Finland is given. The results obtained are analyzed in terms of the objective values and disposal schedules. AB - Several countries utilize nuclear power and face the problem of what to do with the spent nuclear fuel. One possibility, which is under the scope in this paper, is to dispose of the fuel assemblies in the disposal facility. Before the assemblies can be disposed of, they must cool down their decay heat power in the interim storage. Next, they are loaded into canisters in the encapsulation facility, and finally, the canisters are placed in the disposal facility. In this paper, we model this process as a nonsmooth multiobjective mixed-integer nonlinear optimization problem with the minimization of nine objectives: the maximum number of assemblies in the storage, maximum storage time, average storage time, total number of canisters, end time of the encapsulation, operation time of the encapsulation facility, the lengths of disposal and central tunnels, and total costs. As a result, we obtain the disposal schedule i.e., amount of canisters disposed of periodically. We introduce the interactive multiobjective optimization method using the two-slope parameterized achievement scalarizing functions which enables us to obtain systematically several different Pareto optimal solutions from the same preference information. Finally, a case study adapting the disposal in Finland is given. The results obtained are analyzed in terms of the objective values and disposal schedules. KW - achievement scalarizing functions KW - interactive method KW - multiobjective optimization KW - nonsmooth optimization KW - spent nuclear fuel disposal KW - ACHIEVEMENT SCALARIZING FUNCTION KW - BUNDLE METHOD KW - NONSMOOTH KW - CANISTERS U2 - 10.3390/a12120252 DO - 10.3390/a12120252 M3 - Article VL - 12 JO - Algorithms JF - Algorithms SN - 1999-4893 IS - 12 M1 - 252 ER - TY - JOUR T1 - Poincaré inverse problem and torus construction in phase space AU - Laakso, Teemu AU - Kaasalainen, Mikko PY - 2016 Y1 - 2016 N2 - The phase space of an integrable Hamiltonian system is foliated by invariant tori. For an arbitrary Hamiltonian H such a foliation may not exist, but we can artificially construct one through a parameterised family of surfaces, with the intention of finding, in some sense, the closest integrable approximation to H . This is the Poincaré inverse problem (PIP). In this paper, we review the available methods of solving the PIP and present a new iterative approach which works well for the often problematic thin orbits. AB - The phase space of an integrable Hamiltonian system is foliated by invariant tori. For an arbitrary Hamiltonian H such a foliation may not exist, but we can artificially construct one through a parameterised family of surfaces, with the intention of finding, in some sense, the closest integrable approximation to H . This is the Poincaré inverse problem (PIP). In this paper, we review the available methods of solving the PIP and present a new iterative approach which works well for the often problematic thin orbits. KW - Near integrability KW - Invariant torus KW - Torus construction KW - Surface construction in N dimensions KW - Poincare inverse problem KW - Geometric inverse problems U2 - 10.1016/j.physd.2015.10.011 DO - 10.1016/j.physd.2015.10.011 M3 - Article VL - 315 SP - 72 EP - 82 JO - Physica D: Nonlinear Phenomena JF - Physica D: Nonlinear Phenomena SN - 0167-2789 ER - TY - JOUR T1 - Polynomial Input-Output Stability for Linear Systems AU - Paunonen, Lassi AU - Laakkonen, Petteri PY - 2015/10/1 Y1 - 2015/10/1 N2 - We introduce the concept of polynomial input-output stability for infinite-dimensional linear systems. We show that this stability type corresponds exactly to the recent notion of P-stability in the frequency domain. In addition, we show that on a Hilbert space a regular linear system whose system operator generates a polynomially stable semigroup is always polynomially input-output stable, and present additional conditions under which the system is input-output stable. The results are illustrated with an example of a polynomially input-output stable one-dimensional wave system. AB - We introduce the concept of polynomial input-output stability for infinite-dimensional linear systems. We show that this stability type corresponds exactly to the recent notion of P-stability in the frequency domain. In addition, we show that on a Hilbert space a regular linear system whose system operator generates a polynomially stable semigroup is always polynomially input-output stable, and present additional conditions under which the system is input-output stable. The results are illustrated with an example of a polynomially input-output stable one-dimensional wave system. KW - Distributed parameter system KW - Stability UR - http://www.scopus.com/inward/record.url?scp=84942853446&partnerID=8YFLogxK U2 - 10.1109/TAC.2015.2398890 DO - 10.1109/TAC.2015.2398890 M3 - Article VL - 60 SP - 2797 EP - 2802 JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 IS - 10 ER - TY - JOUR T1 - Polynomial stability of semigroups generated by operator matrices AU - Paunonen, Lassi N1 - Published online: 11 July 2014

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-10-20

Publisher name: Birkhaeuser Verlag AG PY - 2014 Y1 - 2014 U2 - 10.1007/s00028-014-0243-5 DO - 10.1007/s00028-014-0243-5 M3 - Article VL - 14 SP - 885 EP - 911 JO - Journal of Evolution Equations JF - Journal of Evolution Equations SN - 1424-3199 IS - 4 ER - TY - JOUR T1 - Predicting Heat Propagation in Roebel-Cable Based Accelerator Magnet Prototype: One-Dimensional Approach with Coupled Turns AU - Ruuskanen, Janne AU - Stenvall, Antti AU - Lahtinen, Valtteri PY - 2017/6 Y1 - 2017/6 N2 - When designing superconductor based magnets, it is of the utmost importance to be prepared for the loss of thermal stability under operation. In this paper, heat propagation during a quench in Roebel-cable based accelerator magnet prototype is predicted using one-dimensional approach. The heat diffusion equation is solved using the finite element method and thermal coupling between the turns is taken into account using thermal network model. However, when reducing the dimensions of the problem, modelling decisions are often unavoidable. Here, we present the challenges of this approach and discuss the appropriateness of these decisions via simulations. AB - When designing superconductor based magnets, it is of the utmost importance to be prepared for the loss of thermal stability under operation. In this paper, heat propagation during a quench in Roebel-cable based accelerator magnet prototype is predicted using one-dimensional approach. The heat diffusion equation is solved using the finite element method and thermal coupling between the turns is taken into account using thermal network model. However, when reducing the dimensions of the problem, modelling decisions are often unavoidable. Here, we present the challenges of this approach and discuss the appropriateness of these decisions via simulations. KW - Delays KW - Heating KW - Magnetic domains KW - Magnetosphere KW - Mathematical model KW - Superconducting magnets KW - Switches KW - Accelerator magnets KW - Finite element methods KW - HTS cables KW - Quench U2 - 10.1109/TASC.2016.2630844 DO - 10.1109/TASC.2016.2630844 M3 - Article VL - 27 JO - IEEE Transactions on Applied Superconductivity JF - IEEE Transactions on Applied Superconductivity SN - 1051-8223 IS - 4 ER - TY - JOUR T1 - Predicting tree structure from tree height using terrestrial laser scanning and quantitative structure models AU - Krooks, Anssi AU - Kaasalainen, Sanna AU - Kankare, Ville AU - Joensuu, Marianna AU - Raumonen, Pasi AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-09-30

Publisher name: The Finnish Society of Forest Science PY - 2014 Y1 - 2014 U2 - 10.14214/sf.1125 DO - 10.14214/sf.1125 M3 - Article VL - 48 SP - 1 EP - 11 JO - Silva Fennica JF - Silva Fennica SN - 0037-5330 IS - 2 M1 - 1125 ER - TY - JOUR T1 - Probabilistic assessment of the influence of lake properties in long-term radiation doses to humans AU - Pohjola, Jari AU - Turunen, Jari AU - Lipping, Tarmo AU - Ikonen, Ari T.K. PY - 2016 Y1 - 2016 N2 - The assessment processes concerning the safety of nuclear waste repositories include the modelling of radionuclide transport in biosphere and the evaluation of the doses to the most affected humans. In this paper, a scenario, in which a contaminated lake is the water source for drinking water, irrigation water and watering of livestock, is presented. The objective of the paper is to probabilistically study the influence of lake properties as parameters in the assessment scenario. The properties of the lake are a result of previously conducted probabilistic studies, where the land uplift of the terrain surrounding the repositories and the formation of water bodies were studied in a 10,000-year time span using Monte Carlo simulation. The lake is formed at 3000 years from present day and the changing properties of the lake have been used in the study. The studied radionuclides 36Cl, 135Cs, 129I, 237Np, 90Sr, 99Tc and 238U enter the lake with a rate of 1 Bq/year. The transport process from the lake water to humans is described and the doses (dose conversion factors) to adult humans are evaluated based on a study on average food consumption. Sensitivity analysis is used for identifying the parameters having the most influence on the outcome of the dose. Based on the results from the sensitivity analysis, the volumetric outflow rate of the lake and the volume of the lake were taken into closer consideration. The results show the influence of probabilistically derived geomorphic lake input parameters on the dose. AB - The assessment processes concerning the safety of nuclear waste repositories include the modelling of radionuclide transport in biosphere and the evaluation of the doses to the most affected humans. In this paper, a scenario, in which a contaminated lake is the water source for drinking water, irrigation water and watering of livestock, is presented. The objective of the paper is to probabilistically study the influence of lake properties as parameters in the assessment scenario. The properties of the lake are a result of previously conducted probabilistic studies, where the land uplift of the terrain surrounding the repositories and the formation of water bodies were studied in a 10,000-year time span using Monte Carlo simulation. The lake is formed at 3000 years from present day and the changing properties of the lake have been used in the study. The studied radionuclides 36Cl, 135Cs, 129I, 237Np, 90Sr, 99Tc and 238U enter the lake with a rate of 1 Bq/year. The transport process from the lake water to humans is described and the doses (dose conversion factors) to adult humans are evaluated based on a study on average food consumption. Sensitivity analysis is used for identifying the parameters having the most influence on the outcome of the dose. Based on the results from the sensitivity analysis, the volumetric outflow rate of the lake and the volume of the lake were taken into closer consideration. The results show the influence of probabilistically derived geomorphic lake input parameters on the dose. U2 - 10.1016/j.jenvrad.2016.08.001 DO - 10.1016/j.jenvrad.2016.08.001 M3 - Article VL - 164 SP - 258 EP - 267 JO - JOURNAL OF ENVIRONMENTAL RADIOACTIVITY JF - JOURNAL OF ENVIRONMENTAL RADIOACTIVITY SN - 0265-931X ER - TY - JOUR T1 - Projektityöskentelyn kehittäminen yläkoulun matematiikan opetuksessa AU - Viro, Ida Elina AU - Joutsenlahti, Jorma PY - 2018 Y1 - 2018 N2 - Perusopetuksen opetussuunnitelman perusteiden 2014 aikana ovat ilmiölähtöinen oppiminen ja projektiluontoinen työskentely lisääntyneet peruskouluissa merkittävästi. Tässä tutkimuksessa tarkastellaan oppilaan ja opettajan näkökulmasta lähinnä yläkoulun matematiikan opetukseen liitetyn projektityöskentelyn kehittämiskohteita sekä niihin mahdollisia kehittämisehdotuksia. Tutkimusaineistoa on kerätty kyselylomakkeilla ja havainnoinnilla LUMA Suomen Projektioppiminen-kehittämishankkeesta, StarT-projektikilpailusta ja Teknologiateollisuuden My TecH –ohjelmasta. Tutkimukseen osallistui 365 oppilasta ja 19 opettajaa. Projektityöskentelyn suurimmat haasteet voidaan luokitella oppilaan ja opettajan toimintaan, itse projektiin tai koulutoiminnan puitteisiin liittyviksi. Jokaiseen osa-alueeseen opettaja voi omalla toiminnallaan vaikuttaa. AB - Perusopetuksen opetussuunnitelman perusteiden 2014 aikana ovat ilmiölähtöinen oppiminen ja projektiluontoinen työskentely lisääntyneet peruskouluissa merkittävästi. Tässä tutkimuksessa tarkastellaan oppilaan ja opettajan näkökulmasta lähinnä yläkoulun matematiikan opetukseen liitetyn projektityöskentelyn kehittämiskohteita sekä niihin mahdollisia kehittämisehdotuksia. Tutkimusaineistoa on kerätty kyselylomakkeilla ja havainnoinnilla LUMA Suomen Projektioppiminen-kehittämishankkeesta, StarT-projektikilpailusta ja Teknologiateollisuuden My TecH –ohjelmasta. Tutkimukseen osallistui 365 oppilasta ja 19 opettajaa. Projektityöskentelyn suurimmat haasteet voidaan luokitella oppilaan ja opettajan toimintaan, itse projektiin tai koulutoiminnan puitteisiin liittyviksi. Jokaiseen osa-alueeseen opettaja voi omalla toiminnallaan vaikuttaa. M3 - Article VL - 2 SP - 90 EP - 99 JO - FMSERA Journal JF - FMSERA Journal SN - 2489-4583 IS - 1 ER - TY - JOUR T1 - Properties of duration drift AU - Kanniainen, Juho AU - Ruohonen, Keijo N1 - ei ut-numeroa 22.3.2014

Contribution: organisation=tta,FACT1=0.8

Contribution: organisation=mat,FACT2=0.2 PY - 2011 Y1 - 2011 M3 - Article VL - 3 SP - 176 EP - 191 JO - International Journal of Economics and Business Research JF - International Journal of Economics and Business Research SN - 1756-9850 IS - 2 ER - TY - JOUR T1 - Quantifying branch architecture of tropical trees using terrestrial LiDAR and 3D modelling AU - Lau, Alvaro AU - Bentley, Lisa Patrick AU - Martius, Christopher AU - Shenkin, Alexander AU - Bartholomeus, Harm AU - Raumonen, Pasi AU - Malhi, Yadvinder AU - Jackson, Tobias AU - Herold, Martin PY - 2018/10 Y1 - 2018/10 N2 - Key message: A method using terrestrial laser scanning and 3D quantitative structure models opens up new possibilities to reconstruct tree architecture from tropical rainforest trees. Abstract: Tree architecture is the three-dimensional arrangement of above ground parts of a tree. Ecologists hypothesize that the topology of tree branches represents optimized adaptations to tree’s environment. Thus, an accurate description of tree architecture leads to a better understanding of how form is driven by function. Terrestrial laser scanning (TLS) has demonstrated its potential to characterize woody tree structure. However, most current TLS methods do not describe tree architecture. Here, we examined nine trees from a Guyanese tropical rainforest to evaluate the utility of TLS for measuring tree architecture. First, we scanned the trees and extracted individual tree point clouds. TreeQSM was used to reconstruct woody structure through 3D quantitative structure models (QSMs). From these QSMs, we calculated: (1) length and diameter of branches > 10 cm diameter, (2) branching order and (3) tree volume. To validate our method, we destructively harvested the trees and manually measured all branches over 10 cm (279). TreeQSM found and reconstructed 95% of the branches thicker than 30 cm. Comparing field and QSM data, QSM overestimated branch lengths thicker than 50 cm by 1% and underestimated diameter of branches between 20 and 60 cm by 8%. TreeQSM assigned the correct branching order in 99% of all cases and reconstructed 87% of branch lengths and 97% of tree volume. Although these results are based on nine trees, they validate a method that is an important step forward towards using tree architectural traits based on TLS and open up new possibilities to use QSMs for tree architecture. AB - Key message: A method using terrestrial laser scanning and 3D quantitative structure models opens up new possibilities to reconstruct tree architecture from tropical rainforest trees. Abstract: Tree architecture is the three-dimensional arrangement of above ground parts of a tree. Ecologists hypothesize that the topology of tree branches represents optimized adaptations to tree’s environment. Thus, an accurate description of tree architecture leads to a better understanding of how form is driven by function. Terrestrial laser scanning (TLS) has demonstrated its potential to characterize woody tree structure. However, most current TLS methods do not describe tree architecture. Here, we examined nine trees from a Guyanese tropical rainforest to evaluate the utility of TLS for measuring tree architecture. First, we scanned the trees and extracted individual tree point clouds. TreeQSM was used to reconstruct woody structure through 3D quantitative structure models (QSMs). From these QSMs, we calculated: (1) length and diameter of branches > 10 cm diameter, (2) branching order and (3) tree volume. To validate our method, we destructively harvested the trees and manually measured all branches over 10 cm (279). TreeQSM found and reconstructed 95% of the branches thicker than 30 cm. Comparing field and QSM data, QSM overestimated branch lengths thicker than 50 cm by 1% and underestimated diameter of branches between 20 and 60 cm by 8%. TreeQSM assigned the correct branching order in 99% of all cases and reconstructed 87% of branch lengths and 97% of tree volume. Although these results are based on nine trees, they validate a method that is an important step forward towards using tree architectural traits based on TLS and open up new possibilities to use QSMs for tree architecture. KW - Destructive harvesting KW - Quantitative structure models KW - Terrestrial LiDAR KW - Tree architecture KW - Tree metrics U2 - 10.1007/s00468-018-1704-1 DO - 10.1007/s00468-018-1704-1 M3 - Article VL - 32 SP - 1219 EP - 1231 JO - TREES-STRUCTURE AND FUNCTION JF - TREES-STRUCTURE AND FUNCTION SN - 0931-1890 IS - 5 ER - TY - JOUR T1 - Quantitative Analysis of Dynamic Association in Live Biological Fluorescent Samples AU - Ruusuvuori, Pekka AU - Paavolainen, Lassi AU - Rutanen, Kalle AU - Maki, Anita AU - Huttunen, Heikki AU - Marjomaki, Varpu N1 - Contribution: organisation=sgn,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Portfolio EDEND: 2014-11-25

Publisher name: Public Library of Science

publication_forum: 65163 PY - 2014/4/11 Y1 - 2014/4/11 N2 - Determining vesicle localization and association in live microscopy may be challenging due to non-simultaneous imaging of rapidly moving objects with two excitation channels. Besides errors due to movement of objects, imaging may also introduce shifting between the image channels, and traditional colocalization methods cannot handle such situations. Our approach to quantifying the association between tagged proteins is to use an object-based method where the exact match of object locations is not assumed. Point-pattern matching provides a measure of correspondence between two point-sets under various changes between the sets. Thus, it can be used for robust quantitative analysis of vesicle association between image channels. Results for a large set of synthetic images shows that the novel association method based on point-pattern matching demonstrates robust capability to detect association of closely located vesicles in live cell-microscopy where traditional colocalization methods fail to produce results. In addition, the method outperforms compared Iterated Closest Points registration method. Results for fixed and live experimental data shows the association method to perform comparably to traditional methods in colocalization studies for fixed cells and to perform favorably in association studies for live cells. AB - Determining vesicle localization and association in live microscopy may be challenging due to non-simultaneous imaging of rapidly moving objects with two excitation channels. Besides errors due to movement of objects, imaging may also introduce shifting between the image channels, and traditional colocalization methods cannot handle such situations. Our approach to quantifying the association between tagged proteins is to use an object-based method where the exact match of object locations is not assumed. Point-pattern matching provides a measure of correspondence between two point-sets under various changes between the sets. Thus, it can be used for robust quantitative analysis of vesicle association between image channels. Results for a large set of synthetic images shows that the novel association method based on point-pattern matching demonstrates robust capability to detect association of closely located vesicles in live cell-microscopy where traditional colocalization methods fail to produce results. In addition, the method outperforms compared Iterated Closest Points registration method. Results for fixed and live experimental data shows the association method to perform comparably to traditional methods in colocalization studies for fixed cells and to perform favorably in association studies for live cells. KW - COLOCALIZATION KW - IMAGES KW - MICROSCOPY KW - REGISTRATION KW - ALGORITHM KW - TRACKING KW - OBJECTS U2 - 10.1371/journal.pone.0094245 DO - 10.1371/journal.pone.0094245 M3 - Article VL - 9 JO - PLoS ONE JF - PLoS ONE SN - 1932-6203 IS - 4 M1 - 94245 ER - TY - JOUR T1 - Radar observations and shape model of asteroid 16 Psyche AU - Shepard, Michael K. AU - Richardson, James AU - Taylor, Patrick A. AU - Rodriguez-Ford, Linda A. AU - Conrad, Al AU - de Pater, Imke AU - Adamkovics, Mate AU - de Kleer, Katherine AU - Males, Jared R. AU - Morzinski, Katie M. AU - Close, Laird M. AU - Kaasalainen, Mikko AU - Viikinkoski, Matti AU - Timerson, Bradley AU - Reddy, Vishnu AU - Magri, Christopher AU - Nolan, Michael C. AU - Howell, Ellen S. AU - Benner, Lance A M AU - Giorgini, Jon D. AU - Warner, Brian D. AU - Harris, Alan W. PY - 2016 Y1 - 2016 N2 - Using the S-band radar at Arecibo Observatory, we observed 16 Psyche, the largest M-class asteroid in the main belt. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images (Drummond et al., 2016) to generate a three-dimensional shape model of Psyche. Our model is consistent with a previously published AO image (Hanus et al., 2013) and three multi-chord occultations. Our shape model has dimensions 279 × 232 × 189 km (± 10%), Deff = 226 ± 23 km, and is 6% larger than, but within the uncertainties of, the most recently published size and shape model generated from the inversion of lightcurves (Hanus et al., 2013). Psyche is roughly ellipsoidal but displays a mass-deficit over a region spanning 90° of longitude. There is also evidence for two ∼50–70 km wide depressions near its south pole. Our size and published masses lead to an overall bulk density estimate of 4500 ± 1400 kgm−3. Psyche's mean radar albedo of 0.37 ± 0.09 is consistent with a near-surface regolith composed largely of iron-nickel and ∼40% porosity. Its radar reflectivity varies by a factor of 1.6 as the asteroid rotates, suggesting global variations in metal abundance or bulk density in the near surface. The variations in radar albedo appear to correlate with large and small-scale shape features. Our size and Psyche's published absolute magnitude lead to an optical albedo of pv = 0.15 ± 0.03, and there is evidence for albedo variegations that correlate with shape features. AB - Using the S-band radar at Arecibo Observatory, we observed 16 Psyche, the largest M-class asteroid in the main belt. We obtained 18 radar imaging and 6 continuous wave runs in November and December 2015, and combined these with 16 continuous wave runs from 2005 and 6 recent adaptive-optics (AO) images (Drummond et al., 2016) to generate a three-dimensional shape model of Psyche. Our model is consistent with a previously published AO image (Hanus et al., 2013) and three multi-chord occultations. Our shape model has dimensions 279 × 232 × 189 km (± 10%), Deff = 226 ± 23 km, and is 6% larger than, but within the uncertainties of, the most recently published size and shape model generated from the inversion of lightcurves (Hanus et al., 2013). Psyche is roughly ellipsoidal but displays a mass-deficit over a region spanning 90° of longitude. There is also evidence for two ∼50–70 km wide depressions near its south pole. Our size and published masses lead to an overall bulk density estimate of 4500 ± 1400 kgm−3. Psyche's mean radar albedo of 0.37 ± 0.09 is consistent with a near-surface regolith composed largely of iron-nickel and ∼40% porosity. Its radar reflectivity varies by a factor of 1.6 as the asteroid rotates, suggesting global variations in metal abundance or bulk density in the near surface. The variations in radar albedo appear to correlate with large and small-scale shape features. Our size and Psyche's published absolute magnitude lead to an optical albedo of pv = 0.15 ± 0.03, and there is evidence for albedo variegations that correlate with shape features. KW - Asteroids KW - Asteroids Composition KW - Radar KW - Surfaces Asteroids U2 - 10.1016/j.icarus.2016.08.011 DO - 10.1016/j.icarus.2016.08.011 M3 - Article VL - 281 SP - 388 EP - 403 JO - Icarus JF - Icarus SN - 0019-1035 ER - TY - JOUR T1 - Radar observations of Itokawa in 2004 and improved shape estimation. AU - Steven, J. Ostro AU - Benner, L.A.M. AU - Magri, C. AU - Giorgini, J.D. AU - Rose, R. AU - Jurgens, R.F. AU - Yeomans, D.K. AU - Hine, A.A. AU - Nolan, M.C. AU - Scheeres, D.J. AU - Broschart, S.B. AU - Kaasalainen, M. AU - Margot, J.-L. N1 - Contribution: organisation=mat,FACT1=1 PY - 2005 Y1 - 2005 U2 - 10.1111/j.1945-5100.2005.tb00131.x DO - 10.1111/j.1945-5100.2005.tb00131.x M3 - Article VL - 40 SP - 1563 EP - 1574 JO - Meteoritics and Planetary Science JF - Meteoritics and Planetary Science SN - 1086-9379 IS - 11 ER - TY - JOUR T1 - Radiometric calibration of LIDAR intensity with commercially available reference targets AU - Kaasalainen, S. AU - Hyyppä, H. AU - Kukko, A. AU - Litkey, P. AU - Ahokas, E. AU - Hyyppä, J. AU - Lehner, H. AU - Jaakkola, A. AU - Suomalainen, J. AU - Akujärvi, A. AU - Kaasalainen, M. AU - Pyysalo, U. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 U2 - 10.1109/TGRS.2008.2003351 DO - 10.1109/TGRS.2008.2003351 M3 - Article VL - 47 SP - 588 EP - 598 JO - IEEE Transactions on Geoscience and Remote Sensing JF - IEEE Transactions on Geoscience and Remote Sensing SN - 0196-2892 IS - 2 ER - TY - JOUR T1 - Raviart-Thomas-type sources adapted to applied EEG and MEG: Implementation and results AU - Pursiainen, Sampsa N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Physics Publishing PY - 2012 Y1 - 2012 U2 - 10.1088/0266-5611/28/6/065013 DO - 10.1088/0266-5611/28/6/065013 M3 - Article VL - 28 JO - Inverse Problems JF - Inverse Problems SN - 0266-5611 IS - 6 M1 - 065013 ER - TY - JOUR T1 - Reduced Order Controller Design for Robust Output Regulation AU - Paunonen, Lassi AU - Phan, Duy PY - 2019/7/22 Y1 - 2019/7/22 N2 - We study robust output regulation for parabolic partial differential equations and other infinite-dimensional linear systems with analytic semigroups. As our main results we show that robust output tracking and disturbance rejection for our class of systems can be achieved using a finite-dimensional controller and present algorithms for construction of two different internal model based robust controllers. The controller parameters are chosen based on a Galerkin approximation of the original PDE system and employ balanced truncation to reduce the orders of the controllers. In the second part of the paper we design controllers for robust output tracking and disturbance rejection for a 1D reaction-diffusion equation with boundary disturbances, a 2D diffusion-convection equation, and a 1D beam equation with Kelvin-Voigt damping. AB - We study robust output regulation for parabolic partial differential equations and other infinite-dimensional linear systems with analytic semigroups. As our main results we show that robust output tracking and disturbance rejection for our class of systems can be achieved using a finite-dimensional controller and present algorithms for construction of two different internal model based robust controllers. The controller parameters are chosen based on a Galerkin approximation of the original PDE system and employ balanced truncation to reduce the orders of the controllers. In the second part of the paper we design controllers for robust output tracking and disturbance rejection for a 1D reaction-diffusion equation with boundary disturbances, a 2D diffusion-convection equation, and a 1D beam equation with Kelvin-Voigt damping. KW - Mathematical model KW - Method of moments KW - Closed loop systems KW - Hilbert space KW - Reduced order systems KW - Adaptive control KW - Robust output regulation KW - partial differential equation KW - controller design KW - Galerkin approximation KW - model reduction U2 - 10.1109/TAC.2019.2930185 DO - 10.1109/TAC.2019.2930185 M3 - Article JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 ER - TY - JOUR T1 - Reduced order internal models in robust output regulation AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-11-29

Publisher name: IEEE PY - 2013 Y1 - 2013 N2 - In this paper we consider robust output regulation and the internal model principle for infinite-dimensional linear systems. We concentrate on a problem where the control law is required to be robust with respect to a restricted class of perturbations. We show that depending on the class of admissible perturbations, it is often possible to construct a robust controller with a smaller internal model than the one given by the internal model principle. In addition, we also look for minimal classes of perturbations that make the full internal model necessary. We introduce a straightforward way of testing for robustness of the control law for a given set of perturbations. The test in particular shows that the robustness is only dependent on the way the perturbations affect the transfer function of the plant at the frequencies of the exosystem. The theoretic results are applied to designing controllers for a one-dimensional wave equation and for a system consisting of three independent shock absorber models. AB - In this paper we consider robust output regulation and the internal model principle for infinite-dimensional linear systems. We concentrate on a problem where the control law is required to be robust with respect to a restricted class of perturbations. We show that depending on the class of admissible perturbations, it is often possible to construct a robust controller with a smaller internal model than the one given by the internal model principle. In addition, we also look for minimal classes of perturbations that make the full internal model necessary. We introduce a straightforward way of testing for robustness of the control law for a given set of perturbations. The test in particular shows that the robustness is only dependent on the way the perturbations affect the transfer function of the plant at the frequencies of the exosystem. The theoretic results are applied to designing controllers for a one-dimensional wave equation and for a system consisting of three independent shock absorber models. U2 - 10.1109/TAC.2013.2257596 DO - 10.1109/TAC.2013.2257596 M3 - Article VL - 58 SP - 2307 EP - 2318 JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 IS - 9 ER - TY - JOUR T1 - Regional compensation for statistical maximum likelihood reconstruction error of PET image pixels AU - Forma, J. AU - Niemi, J.A. AU - Ruotsalainen, U. N1 - Contribution: organisation=sgn,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Portfolio EDEND: 2013-07-29

Publisher name: IOP Publishing PY - 2013 Y1 - 2013 U2 - 10.1088/0031-9155/58/14/4849 DO - 10.1088/0031-9155/58/14/4849 M3 - Article VL - 58 SP - 4849 EP - 4864 JO - Physics in Medicine and Biology JF - Physics in Medicine and Biology SN - 0031-9155 IS - 14 ER - TY - JOUR T1 - Robust controller design for infinite-dimensional exosystems AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Online first

Contribution: organisation=mat,FACT1=1

Publisher name: John Wiley & Sons PY - 2014 Y1 - 2014 U2 - 10.1002/rnc.2920 DO - 10.1002/rnc.2920 M3 - Article VL - 24 SP - 825 EP - 858 JO - International Journal of Robust and Nonlinear Control JF - International Journal of Robust and Nonlinear Control SN - 1049-8923 IS - 5 ER - TY - JOUR T1 - Robust controllers for regular linear systems with infinite-dimensional exosystems AU - Paunonen, Lassi PY - 2017 Y1 - 2017 N2 - We construct two error feedback controllers for robust output tracking and disturbance rejection of a regular linear system with nonsmooth reference and disturbance signals. We show that for sufficiently smooth signals the output converges to the reference at a rate that depends on the behavior of the transfer function of the plant on the imaginary axis. In addition, we construct a controller that can be designed to achieve robustness with respect to a given class of uncertainties in the system, and we present a novel controller structure for output tracking and disturbance rejection without the robustness requirement. We also generalize the internal model principle for regular linear systems with boundary disturbance and for controllers with unbounded input and output operators. The construction of controllers is illustrated with an example where we consider output tracking of a nonsmooth periodic reference signal for a two-dimensional heat equation with boundary control and observation, and with periodic disturbances on the boundary. AB - We construct two error feedback controllers for robust output tracking and disturbance rejection of a regular linear system with nonsmooth reference and disturbance signals. We show that for sufficiently smooth signals the output converges to the reference at a rate that depends on the behavior of the transfer function of the plant on the imaginary axis. In addition, we construct a controller that can be designed to achieve robustness with respect to a given class of uncertainties in the system, and we present a novel controller structure for output tracking and disturbance rejection without the robustness requirement. We also generalize the internal model principle for regular linear systems with boundary disturbance and for controllers with unbounded input and output operators. The construction of controllers is illustrated with an example where we consider output tracking of a nonsmooth periodic reference signal for a two-dimensional heat equation with boundary control and observation, and with periodic disturbances on the boundary. KW - Controller Design KW - Feedback KW - Regular Linear Systems KW - Robust Output Regulation KW - Stability U2 - 10.1137/16M107181X DO - 10.1137/16M107181X M3 - Article VL - 55 SP - 1567 EP - 1597 JO - SIAM Journal on Control and Optimization JF - SIAM Journal on Control and Optimization SN - 0363-0129 IS - 3 ER - TY - JOUR T1 - Robustness of polynomial stability with respect to unbounded perturbations AU - Paunonen, Lassi N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-07-29

Publisher name: Elsevier PY - 2013 Y1 - 2013 N2 - In this paper we present conditions for the preservation of strong and polynomial stability of a strongly continuous semigroup under unbounded finite rank perturbations of its infinitesimal generator. In addition, we also improve recent perturbation results for bounded finite rank perturbations. The results are illustrated with two examples. In the first one we consider the preservation of stability of a one-dimensional wave equation that has been stabilized polynomially with boundary feedback. In the second example we find conditions for the preservation of polynomial stability of a multiplication semigroup under unbounded rank one perturbations. AB - In this paper we present conditions for the preservation of strong and polynomial stability of a strongly continuous semigroup under unbounded finite rank perturbations of its infinitesimal generator. In addition, we also improve recent perturbation results for bounded finite rank perturbations. The results are illustrated with two examples. In the first one we consider the preservation of stability of a one-dimensional wave equation that has been stabilized polynomially with boundary feedback. In the second example we find conditions for the preservation of polynomial stability of a multiplication semigroup under unbounded rank one perturbations. U2 - 10.1016/j.sysconle.2013.01.005 DO - 10.1016/j.sysconle.2013.01.005 M3 - Article VL - 62 SP - 331 EP - 337 JO - Systems and Control Letters JF - Systems and Control Letters SN - 0167-6911 IS - 4 ER - TY - JOUR T1 - Robustness of strongly and polynomially stable semigroups AU - Paunonen, Lassi N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Academic Press PY - 2012 Y1 - 2012 N2 - In this paper we study the robustness properties of strong and polynomial stability of semigroups of operators. We show that polynomial stability of a semigroup is robust with respect to a large and easily identifiable class of perturbations to its infinitesimal generator. The presented results apply to general polynomially stable semigroups and bounded perturbations. The conditions on the perturbations generalize well-known criteria for the preservation of exponential stablity of semigroups. We also show that the general results can be improved if the perturbation is of finite rank or if the semigroup is generated by a Riesz-spectral operator. The theory is applied to deriving concrete conditions for the preservation of stability of a strongly stabilized one-dimensional wave equation. AB - In this paper we study the robustness properties of strong and polynomial stability of semigroups of operators. We show that polynomial stability of a semigroup is robust with respect to a large and easily identifiable class of perturbations to its infinitesimal generator. The presented results apply to general polynomially stable semigroups and bounded perturbations. The conditions on the perturbations generalize well-known criteria for the preservation of exponential stablity of semigroups. We also show that the general results can be improved if the perturbation is of finite rank or if the semigroup is generated by a Riesz-spectral operator. The theory is applied to deriving concrete conditions for the preservation of stability of a strongly stabilized one-dimensional wave equation. U2 - 10.1016/j.jfa.2012.08.023 DO - 10.1016/j.jfa.2012.08.023 M3 - Article VL - 263 SP - 2555 EP - 2583 JO - Journal of Functional Analysis JF - Journal of Functional Analysis SN - 0022-1236 IS - 9 ER - TY - JOUR T1 - Robustness of strong stability of discrete semigroups AU - Paunonen, Lassi N1 - Siirretään Portfolio15

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2015-01-08

Publisher name: Elsevier BV PY - 2015 Y1 - 2015 N2 - In this paper we study the robustness of strong stability of a discrete semigroup on a Hilbert space under bounded perturbations. As the main result we present classes of perturbations preserving the strong stability of the semigroup. AB - In this paper we study the robustness of strong stability of a discrete semigroup on a Hilbert space under bounded perturbations. As the main result we present classes of perturbations preserving the strong stability of the semigroup. U2 - 10.1016/j.sysconle.2014.11.004 DO - 10.1016/j.sysconle.2014.11.004 M3 - Article VL - 75 SP - 35 EP - 40 JO - Systems and Control Letters JF - Systems and Control Letters SN - 0167-6911 ER - TY - JOUR T1 - Robustness of strong stability of semigroups AU - Paunonen, Lassi N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-10-20

Publisher name: Academic Press PY - 2014 Y1 - 2014 U2 - 10.1016/j.jde.2014.08.011 DO - 10.1016/j.jde.2014.08.011 M3 - Article VL - 257 SP - 4403 EP - 4436 JO - Journal of Differential Equations JF - Journal of Differential Equations SN - 0022-0396 IS - 12 ER - TY - JOUR T1 - Robust output regulation and the preservation of polynomial closed-loop stability AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Online first; Article first published online: 24 AUG 2013

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-11-29

Publisher name: John Wiley & Sons PY - 2013 Y1 - 2013 U2 - 10.1002/rnc.3064 DO - 10.1002/rnc.3064 M3 - Article SP - 1 EP - 28 JO - International Journal of Robust and Nonlinear Control JF - International Journal of Robust and Nonlinear Control SN - 1049-8923 ER - TY - JOUR T1 - Robust regulation of distributed parameter systems with infinite-dimensional exosystems AU - Hämäläinen, Timo AU - Pohjolainen, Seppo N1 - poistettu tupla r=3127

Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1137/090757976 DO - 10.1137/090757976 M3 - Article VL - 48 SP - 4846 EP - 4873 JO - SIAM Journal on Control and Optimization JF - SIAM Journal on Control and Optimization SN - 0363-0129 IS - 8 ER - TY - JOUR T1 - Robust Regulation of Infinite-Dimensional Port-Hamiltonian Systems AU - Humaloja, Jukka-Pekka AU - Paunonen, Lassi PY - 2018 Y1 - 2018 N2 - We will give general sufficient conditions under which a controller achieves robust regulation for a boundary control and observation system. Utilizing these conditions we construct a minimal order robust controller for an arbitrary order impedance passive linear port-Hamiltonian system. The theoretical results are illustrated with a numerical example where we implement a controller for a one-dimensional Euler-Bernoulli beam with boundary controls and boundary observations. AB - We will give general sufficient conditions under which a controller achieves robust regulation for a boundary control and observation system. Utilizing these conditions we construct a minimal order robust controller for an arbitrary order impedance passive linear port-Hamiltonian system. The theoretical results are illustrated with a numerical example where we implement a controller for a one-dimensional Euler-Bernoulli beam with boundary controls and boundary observations. KW - Aerospace electronics KW - Closed loop systems KW - distributed parameter systems KW - Generators KW - Impedance KW - linear systems KW - port-Hamiltonian systems KW - robust control KW - Robustness KW - Transfer functions U2 - 10.1109/TAC.2017.2748055 DO - 10.1109/TAC.2017.2748055 M3 - Article VL - 63 JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 IS - 5 ER - TY - JOUR T1 - Robust Regulation Theory for Transfer Functions With a Coprime Factorization AU - Laakkonen, Petteri PY - 2015 Y1 - 2015 N2 - Classical frequency domain results of robust regulation are extended by requiring only a right or a left coprime factorization of a plant, but not both. The famous internal model principle is generalized first, which leads to a necessary and sufficient solvability condition of the robust regulation problem and to a parametrization of all robustly regulating controllers. In addition, a procedure for constructing robustly regulating controllers is proposed. AB - Classical frequency domain results of robust regulation are extended by requiring only a right or a left coprime factorization of a plant, but not both. The famous internal model principle is generalized first, which leads to a necessary and sufficient solvability condition of the robust regulation problem and to a parametrization of all robustly regulating controllers. In addition, a procedure for constructing robustly regulating controllers is proposed. KW - Frequency-domain analysis KW - Nickel KW - Robustness KW - Stability analysis KW - Topology KW - Transfer functions KW - Yttrium KW - Distributed parameter systems KW - linear systems KW - parametrization KW - robust control U2 - 10.1109/TAC.2015.2497898 DO - 10.1109/TAC.2015.2497898 M3 - Article JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 ER - TY - JOUR T1 - RS-BL-algebras are MV-algebras AU - Turunen, Esko PY - 2016/12/1 Y1 - 2016/12/1 N2 - We prove that RS-BL-algebras are MV-algebras. AB - We prove that RS-BL-algebras are MV-algebras. M3 - Article VL - 13 SP - 153 EP - 154 JO - Iranian Journal of Fuzzy Systems JF - Iranian Journal of Fuzzy Systems SN - 1735-0654 IS - 6 ER - TY - JOUR T1 - Satisfiability of modal inclusion logic T2 - Lax and strict semantics AU - Hella, Lauri AU - Kuusisto, Antti AU - Meier, Arne AU - Vollmer, Heribert N1 - DUPL=50949587 PY - 2019/10/1 Y1 - 2019/10/1 N2 - We investigate the computational complexity of the satisfiability problem of modal inclusion logic. We distinguish two variants of the problem: one for the strict and another one for the lax semantics. Both problems turn out to be EXPTIME-complete on general structures. Finally,we showhowfor a specific class of structures NEXPTIME-completeness for these problems under strict semantics can be achieved. AB - We investigate the computational complexity of the satisfiability problem of modal inclusion logic. We distinguish two variants of the problem: one for the strict and another one for the lax semantics. Both problems turn out to be EXPTIME-complete on general structures. Finally,we showhowfor a specific class of structures NEXPTIME-completeness for these problems under strict semantics can be achieved. KW - Computational complexity KW - Modal inclusion logic KW - Satisfiability KW - Team semantics U2 - 10.1145/3356043 DO - 10.1145/3356043 M3 - Article VL - 21 JO - ACM TRANSACTIONS ON COMPUTATIONAL LOGIC JF - ACM TRANSACTIONS ON COMPUTATIONAL LOGIC SN - 1529-3785 IS - 1 M1 - 7 ER - TY - JOUR T1 - Semantic Labeling of User Location Context Based on Phone Usage Features AU - Leppäkoski, Helena AU - Rivero-Rodriguez, Alejandro AU - Rautalin, Sakari AU - Muñoz Martínez, David AU - Käppi, Jani AU - Ali-Löytty, Simo AU - Piche, Robert N1 - INT=mat,”Rautalin, Sakari” PY - 2017/8/24 Y1 - 2017/8/24 N2 - In mobile phones, the awareness of the user’s context allows services better tailored to the user’s needs. We propose a machine learning based method for semantic labeling that utilizes phone usage features to detect the user’s home, work, and other visited places. For place detection, we compare seven different classification methods. We organize the phone usage data based on periods of uninterrupted time that the user has been in a certain place. We consider three approaches to represent this data: visits, places, and cumulative samples. Our main contribution is semantic place labeling using a small set of privacy-preserving features and novel data representations suitable for resource constrained mobile devices. The contributions include (1) introduction of novel data representations including accumulation and averaging of the usage, (2) analysis of the effect of the data accumulation time on the accuracy of the place classification, (3) analysis of the confidence on the classification outcome, and (4) identification of the most relevant features obtained through feature selection methods. With a small set of privacy-preserving features and our data representations, we detect the user’s home and work with probability of 90% or better, and in 3-class problem the overall classification accuracy was 89% or better. AB - In mobile phones, the awareness of the user’s context allows services better tailored to the user’s needs. We propose a machine learning based method for semantic labeling that utilizes phone usage features to detect the user’s home, work, and other visited places. For place detection, we compare seven different classification methods. We organize the phone usage data based on periods of uninterrupted time that the user has been in a certain place. We consider three approaches to represent this data: visits, places, and cumulative samples. Our main contribution is semantic place labeling using a small set of privacy-preserving features and novel data representations suitable for resource constrained mobile devices. The contributions include (1) introduction of novel data representations including accumulation and averaging of the usage, (2) analysis of the effect of the data accumulation time on the accuracy of the place classification, (3) analysis of the confidence on the classification outcome, and (4) identification of the most relevant features obtained through feature selection methods. With a small set of privacy-preserving features and our data representations, we detect the user’s home and work with probability of 90% or better, and in 3-class problem the overall classification accuracy was 89% or better. U2 - 10.1155/2017/3876906 DO - 10.1155/2017/3876906 M3 - Article VL - 2017 SP - 1 EP - 21 JO - Mobile Information Systems JF - Mobile Information Systems SN - 1574-017X ER - TY - JOUR T1 - Shape modeling technique KOALA validated by ESA Rosetta at (21) Lutetia AU - Carry, B. AU - Kaasalainen, Mikko AU - Merline, W.J. AU - Muller, T.G. AU - Jorda, L. AU - Drummond, J.D. AU - Berthier, J. AU - O'Rourke, L. AU - Durech, J. AU - Küppers, M. AU - Conrad, A. AU - Tamblyn, P. AU - Dumas, C. AU - Sierks, H. N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Pergamon PY - 2012 Y1 - 2012 U2 - 10.1016/j.pss.2011.12.018 DO - 10.1016/j.pss.2011.12.018 M3 - Article VL - 66 SP - 200 EP - 212 JO - Planetary and Space Science JF - Planetary and Space Science SN - 0032-0633 IS - 1 ER - TY - JOUR T1 - Shape model of asteroid (130) Elektra from optical photometry and disk-resolved images from VLT/SPHERE and Nirc2/Keck AU - Hanuš, J. AU - Marchis, F. AU - Viikinkoski, M. AU - Yang, B. AU - Kaasalainen, M. PY - 2017/3/1 Y1 - 2017/3/1 N2 - Context. Asteroid (130) Elektra belongs to one of the six known triple asteroids in the main belt, so its mass has been reliably determined.Aims. We aim to use all available disk-resolved images of (130) Elektra obtained by the SPHERE instrument at VLT and by the Nirc2 of the Keck telescope together with the disk-integrated photometry to determine its shape model and its size. The volume can be then used in combination with the known mass to derive the bulk density of the primary.Methods. We have applied the All-Data Asteroid Modeling (ADAM) algorithm to the optical disk-integrated data, two disk-resolved images obtained by the SPHERE instrument, and 13 disk-resolved images from the Nirc2 of the Keck telescope. We have also derived the shape model and size of Elektra.Results. We present the shape model, volume-equivalent diameter (199 ± 7 km) and bulk density (1.60 ± 0.13 g cm-3) of the C-type asteroid Elektra. AB - Context. Asteroid (130) Elektra belongs to one of the six known triple asteroids in the main belt, so its mass has been reliably determined.Aims. We aim to use all available disk-resolved images of (130) Elektra obtained by the SPHERE instrument at VLT and by the Nirc2 of the Keck telescope together with the disk-integrated photometry to determine its shape model and its size. The volume can be then used in combination with the known mass to derive the bulk density of the primary.Methods. We have applied the All-Data Asteroid Modeling (ADAM) algorithm to the optical disk-integrated data, two disk-resolved images obtained by the SPHERE instrument, and 13 disk-resolved images from the Nirc2 of the Keck telescope. We have also derived the shape model and size of Elektra.Results. We present the shape model, volume-equivalent diameter (199 ± 7 km) and bulk density (1.60 ± 0.13 g cm-3) of the C-type asteroid Elektra. KW - Methods: numerical KW - Methods: observational KW - Minor planets, asteroids: individual: (130) Elektra U2 - 10.1051/0004-6361/201629592 DO - 10.1051/0004-6361/201629592 M3 - Article VL - 599 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A36 ER - TY - JOUR T1 - Shape reconstruction from images: Pixel fields and Fourier transform AU - Viikinkoski, Matti AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-17

Publisher name: American Institute of Mathematical Sciences PY - 2014 Y1 - 2014 U2 - 10.3934/ipi.2014.8.885 DO - 10.3934/ipi.2014.8.885 M3 - Article VL - 8 SP - 885 EP - 900 JO - Inverse Problems and Imaging JF - Inverse Problems and Imaging SN - 1930-8337 IS - 3 ER - TY - JOUR T1 - Shape reconstruction of irregular bodies with multiple complementary data sources AU - Kaasalainen, Mikko AU - Viikinkoski, Matti N1 - Contribution: organisation=mat,FACT1=1

Publisher name: EDP Sciences PY - 2012 Y1 - 2012 U2 - 10.1051/0004-6361/201219267 DO - 10.1051/0004-6361/201219267 M3 - Article VL - 543 SP - 9 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A97 ER - TY - JOUR T1 - Shape, size and multiplicity of main-belt asteroids. I. Keck adaptive optics survey AU - Marchis, F. AU - Kaasalainen, M. AU - Hom, E. AU - Berthier, J. AU - Enriquez, J. AU - Hestroffer, D. AU - Le Mignant, D. AU - de Pater, I. N1 - Contribution: organisation=mat,FACT1=1 PY - 2006 Y1 - 2006 U2 - 10.1016/j.icarus.2006.06.001 DO - 10.1016/j.icarus.2006.06.001 M3 - Article VL - 185 SP - 39 EP - 63 JO - Icarus JF - Icarus SN - 0019-1035 IS - 1 ER - TY - JOUR T1 - Similar temperature sensitivity of soil mineral-associated organic carbon regardless of age AU - Karhu, Kristiina AU - Hilasvuori, Emmi AU - Järvenpää, Marko AU - Arppe, Laura AU - Christensen, Bent T. AU - Fritze, Hannu AU - Kulmala, Liisa AU - Oinonen, Markku AU - Pitkänen, Juha Matti AU - Vanhala, Pekka AU - Heinonsalo, Jussi AU - Liski, Jari PY - 2019/9/1 Y1 - 2019/9/1 N2 - Most of the carbon (C) stored in temperate arable soils is present in organic matter (OM) intimately associated with soil minerals and with slow turnover rates. The sensitivity of mineral-associated OM to changes in temperature is crucial for reliable predictions of the response of soil C turnover to global warming and the associated flux of carbon dioxide (CO2) from the soil to the atmosphere. We studied the temperature sensitivity of C in <63 μm fractions rich in mineral-associated organic matter (MOM) and of C in >63 μm fractions rich in particulate organic matter (POM). The fractions were isolated by physical separation of two light-textured arable soils where the C4-plant silage maize had replaced C3-crops 25 years ago. Differences in 13C abundance allowed for calculation of the age of C in the soil-size fractions (old C, C3–C > 25 years; recent C, C4–C < 25 years). We incubated bulk soils (<2 mm) and size fractions sequentially at 6, 18, 26 and 34 °C (ramping up and down the temperature scale) and calculated the temperature sensitivity of old and recent C from 12CO2 and 13CO2 evolution rates. The temperature sensitivity was similar or slightly higher for POM than for MOM. Within the POM fraction, old C3–C was more sensitive to changes in temperature than recent C4–C. For the MOM fraction, the temperature sensitivity was unrelated to the age of C. Quantitative PCR analysis indicated that the proportions of bacteria, archaea and fungi did not change during incubation. Our results suggest that while OM stabilizing mechanisms affect the temperature sensitivity of soil C, temperature sensitivity appears unrelated to the age of mineral-associated OM. AB - Most of the carbon (C) stored in temperate arable soils is present in organic matter (OM) intimately associated with soil minerals and with slow turnover rates. The sensitivity of mineral-associated OM to changes in temperature is crucial for reliable predictions of the response of soil C turnover to global warming and the associated flux of carbon dioxide (CO2) from the soil to the atmosphere. We studied the temperature sensitivity of C in <63 μm fractions rich in mineral-associated organic matter (MOM) and of C in >63 μm fractions rich in particulate organic matter (POM). The fractions were isolated by physical separation of two light-textured arable soils where the C4-plant silage maize had replaced C3-crops 25 years ago. Differences in 13C abundance allowed for calculation of the age of C in the soil-size fractions (old C, C3–C > 25 years; recent C, C4–C < 25 years). We incubated bulk soils (<2 mm) and size fractions sequentially at 6, 18, 26 and 34 °C (ramping up and down the temperature scale) and calculated the temperature sensitivity of old and recent C from 12CO2 and 13CO2 evolution rates. The temperature sensitivity was similar or slightly higher for POM than for MOM. Within the POM fraction, old C3–C was more sensitive to changes in temperature than recent C4–C. For the MOM fraction, the temperature sensitivity was unrelated to the age of C. Quantitative PCR analysis indicated that the proportions of bacteria, archaea and fungi did not change during incubation. Our results suggest that while OM stabilizing mechanisms affect the temperature sensitivity of soil C, temperature sensitivity appears unrelated to the age of mineral-associated OM. KW - C natural abundance KW - Bayesian statistics KW - Climate change KW - Decomposition KW - Soil organic matter KW - Temperature sensitivity U2 - 10.1016/j.soilbio.2019.107527 DO - 10.1016/j.soilbio.2019.107527 M3 - Article VL - 136 JO - Soil Biology and Biochemistry JF - Soil Biology and Biochemistry SN - 0038-0717 M1 - 107527 ER - TY - JOUR T1 - SimpleTree T2 - An Efficient Open Source Tool to Build Tree Models from TLS Clouds AU - Hackenberg, Jan AU - Spiecker, Heinrich AU - Calders, Kim AU - Disney, Mathias AU - Raumonen, Pasi PY - 2015/11/23 Y1 - 2015/11/23 N2 - An open source tool named SimpleTree, capable of modelling highly accurate cylindrical tree models from terrestrial laser scan point clouds, is presented and evaluated. All important functionalities, accessible in the software via buttons and dialogues, are described including the explanation of all necessary input parameters. The method is validated utilizing 101 point clouds of six different tree species, in the main evergreen and coniferous trees. All scanned trees have been destructively harvested to get accurate estimates of above ground biomass with which we assess the accuracy of the SimpleTree-reconstructed cylinder models. The trees were grouped into four data sets and for each one a Concordance Correlation Coefficient of at least 0.92 (0.92, 0.97, 0.92, 0.94) and an total relative error at most ~8 % (2.42%, 3.59%, –4.59%, 8.27%) was achieved in the comparison of the model results to the ground truth data. A global statistical improvement of derived cylinder radii is presented as well as an efficient optimization approach to automatically improve user given input parameters. An additional check of the SimpleTree results is presented via comparison to the results of trees reconstructed using an alternative, published method. AB - An open source tool named SimpleTree, capable of modelling highly accurate cylindrical tree models from terrestrial laser scan point clouds, is presented and evaluated. All important functionalities, accessible in the software via buttons and dialogues, are described including the explanation of all necessary input parameters. The method is validated utilizing 101 point clouds of six different tree species, in the main evergreen and coniferous trees. All scanned trees have been destructively harvested to get accurate estimates of above ground biomass with which we assess the accuracy of the SimpleTree-reconstructed cylinder models. The trees were grouped into four data sets and for each one a Concordance Correlation Coefficient of at least 0.92 (0.92, 0.97, 0.92, 0.94) and an total relative error at most ~8 % (2.42%, 3.59%, –4.59%, 8.27%) was achieved in the comparison of the model results to the ground truth data. A global statistical improvement of derived cylinder radii is presented as well as an efficient optimization approach to automatically improve user given input parameters. An additional check of the SimpleTree results is presented via comparison to the results of trees reconstructed using an alternative, published method. UR - http://www.mdpi.com/1999-4907/6/11/4245 U2 - 10.3390/f6114245 DO - 10.3390/f6114245 M3 - Article VL - 6 SP - 4245 EP - 4294 JO - Forests: Open Access Journal JF - Forests: Open Access Journal SN - 1999-4907 IS - 11 ER - TY - JOUR T1 - Simulating solar-induced chlorophyll fluorescence in a boreal forest stand reconstructed from terrestrial laser scanning measurements AU - Liu, Weiwei AU - Atherton, Jon AU - Mõttus, Matti AU - Gastellu-Etchegorry, Jean Philippe AU - Malenovský, Zbyněk AU - Raumonen, Pasi AU - Åkerblom, Markku AU - Mäkipää, Raisa AU - Porcar-Castell, Albert PY - 2019 Y1 - 2019 N2 - Solar-induced chlorophyll fluorescence (SIF) has been shown to be a suitable remote sensing proxy of photosynthesis at multiple scales. However, the relationship between fluorescence and photosynthesis observed at the leaf level cannot be directly applied to the interpretation of retrieved SIF due to the impact of canopy structure. We carried out a SIF modelling study for a heterogeneous forest canopy considering the effect of canopy structure in the Discrete Anisotropic Radiative Transfer (DART) model. A 3D forest simulation scene consisting of realistic trees and understory, including multi-scale clumping at branch and canopy level, was constructed from terrestrial laser scanning data using the combined model TreeQSM and FaNNI for woody structure and leaf insertion, respectively. Next, using empirical data and a realistic range of leaf-level biochemical and physiological parameters, we conducted a local sensitivity analysis to demonstrate the potential of the approach for assessing the impact of structural, biochemical and physiological factors on top of canopy (TOC) SIF. The analysis gave insight into the factors that drive the intensity and spectral properties of TOC SIF in heterogeneous boreal forest canopies. DART simulated red TOC fluorescence was found to be less affected by biochemical factors such as chlorophyll and dry matter contents or the senescent factor than far-red fluorescence. In contrast, canopy structural factors such as overstory leaf area index (LAI), leaf angle distribution and fractional cover had a substantial and comparable impact across all SIF wavelengths, with the exception of understory LAI that affected predominantly far-red fluorescence. Finally, variations in the fluorescence quantum efficiency (Fqe) of photosystem II affected all TOC SIF wavelengths. Our results also revealed that not only canopy structural factors but also understory fluorescence should be considered in the interpretation of tower, airborne and satellite SIF datasets, especially when acquired in the (near-) nadir viewing direction and for forests with open canopies. We suggest that the modelling strategy introduced in this study, coupled with the increasing availability of TLS and other 3D data sources, can be applied to resolve the interplay between physiological, biochemical and structural factors affecting SIF across ecosystems and independently of canopy complexity, paving the way for future SIF-based 3D photosynthesis models. AB - Solar-induced chlorophyll fluorescence (SIF) has been shown to be a suitable remote sensing proxy of photosynthesis at multiple scales. However, the relationship between fluorescence and photosynthesis observed at the leaf level cannot be directly applied to the interpretation of retrieved SIF due to the impact of canopy structure. We carried out a SIF modelling study for a heterogeneous forest canopy considering the effect of canopy structure in the Discrete Anisotropic Radiative Transfer (DART) model. A 3D forest simulation scene consisting of realistic trees and understory, including multi-scale clumping at branch and canopy level, was constructed from terrestrial laser scanning data using the combined model TreeQSM and FaNNI for woody structure and leaf insertion, respectively. Next, using empirical data and a realistic range of leaf-level biochemical and physiological parameters, we conducted a local sensitivity analysis to demonstrate the potential of the approach for assessing the impact of structural, biochemical and physiological factors on top of canopy (TOC) SIF. The analysis gave insight into the factors that drive the intensity and spectral properties of TOC SIF in heterogeneous boreal forest canopies. DART simulated red TOC fluorescence was found to be less affected by biochemical factors such as chlorophyll and dry matter contents or the senescent factor than far-red fluorescence. In contrast, canopy structural factors such as overstory leaf area index (LAI), leaf angle distribution and fractional cover had a substantial and comparable impact across all SIF wavelengths, with the exception of understory LAI that affected predominantly far-red fluorescence. Finally, variations in the fluorescence quantum efficiency (Fqe) of photosystem II affected all TOC SIF wavelengths. Our results also revealed that not only canopy structural factors but also understory fluorescence should be considered in the interpretation of tower, airborne and satellite SIF datasets, especially when acquired in the (near-) nadir viewing direction and for forests with open canopies. We suggest that the modelling strategy introduced in this study, coupled with the increasing availability of TLS and other 3D data sources, can be applied to resolve the interplay between physiological, biochemical and structural factors affecting SIF across ecosystems and independently of canopy complexity, paving the way for future SIF-based 3D photosynthesis models. KW - Boreal forest KW - DART KW - FaNNI KW - Far-red SIF KW - LiDAR KW - Red SIF KW - Silver birch KW - Solar-induced chlorophyll fluorescence KW - TreeQSM KW - Understory U2 - 10.1016/j.rse.2019.111274 DO - 10.1016/j.rse.2019.111274 M3 - Article JO - Remote Sensing of Environment JF - Remote Sensing of Environment SN - 0034-4257 M1 - 111274 ER - TY - JOUR T1 - Small-angle goniometry for backscattering measurements in the broadband spectrum AU - Kaasalainen, S. AU - Peltoniemi, J. AU - Näränen, J. AU - Suomalainen, J. AU - Kaasalainen, M. AU - Stenman, F. N1 - Contribution: organisation=mat,FACT1=1 PY - 2005 Y1 - 2005 U2 - 10.1364/AO.44.001485 DO - 10.1364/AO.44.001485 M3 - Article VL - 44 SP - 1485 EP - 1490 JO - Applied Optics JF - Applied Optics SN - 1559-128X IS - 8 ER - TY - JOUR T1 - SO-I: a surrogate model algorithm for expensive nonlinear integer programming problems including global optimization applications AU - Müller, Juliane AU - Shoemaker, Christine AU - Piche, Robert N1 - Online first

Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2013-10-29

Publisher name: Springer US PY - 2013 Y1 - 2013 U2 - 10.1007/s10898-013-0101-y DO - 10.1007/s10898-013-0101-y M3 - Article SP - 1 EP - 25 JO - Journal of Global Optimization JF - Journal of Global Optimization SN - 0925-5001 ER - TY - JOUR T1 - Some remarks on structural matrix rings and matrices with ideal entries AU - Foldes, Stephan AU - Meletiou, Gerasimos N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Article VL - 12 SP - 25 EP - 29 JO - Miskolc Mathematical Notes JF - Miskolc Mathematical Notes SN - 1787-2405 IS - 1 ER - TY - JOUR T1 - Some Ring Theory from Jeno Szigeti AU - Foldes, Stephane PY - 2015 Y1 - 2015 N2 - A selection of ring theory papers by Jeno Szigeti is reviewed with an emphasis on aspects related to matrix algebras. AB - A selection of ring theory papers by Jeno Szigeti is reviewed with an emphasis on aspects related to matrix algebras. KW - LIE NILPOTENT RINGS KW - MATRIX-RINGS KW - POLYNOMIAL-IDENTITIES KW - DETERMINANTS KW - ALGEBRAS M3 - Article VL - 16 SP - 115 EP - 121 JO - Miskolc Mathematical Notes JF - Miskolc Mathematical Notes SN - 1787-2405 IS - 1 ER - TY - JOUR T1 - SO-MI: A surrogate model algorithm for computationally expensive nonlinear mixed-integer black-box global optimization problems AU - Müller, Juliane AU - Shoemaker, C. AU - Piche, Robert N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Pergamon PY - 2013 Y1 - 2013 N2 - This paper introduces a surrogate model based algorithm for computationally expensive mixed-integer black-box global optimization problems with both binary and non-binary integer variables that may have computationally expensive constraints. The goal is to find accurate solutions with relatively few function evaluations. A radial basis function surrogate model (response surface) is used to select candidates for integer and continuous decision variable points at which the computationally expensive objective and constraint functions are to be evaluated. In every iteration multiple new points are selected based on different methods, and the function evaluations are done in parallel. The algorithm converges to the global optimum almost surely. The performance of this new algorithm, SO-MI, is compared to a branch and bound algorithm for nonlinear problems, a genetic algorithm, and the NOMAD (Nonsmooth Optimization by Mesh Adaptive Direct Search) algorithm for mixed-integer problems on 16 test problems from the literature (constrained, unconstrained, unimodal and multimodal problems), as well as on two application problems arising from structural optimization, and three application problems from optimal reliability design. The numerical experiments show that SO-MI reaches significantly better results than the other algorithms when the number of function evaluations is very restricted (200–300 evaluations). AB - This paper introduces a surrogate model based algorithm for computationally expensive mixed-integer black-box global optimization problems with both binary and non-binary integer variables that may have computationally expensive constraints. The goal is to find accurate solutions with relatively few function evaluations. A radial basis function surrogate model (response surface) is used to select candidates for integer and continuous decision variable points at which the computationally expensive objective and constraint functions are to be evaluated. In every iteration multiple new points are selected based on different methods, and the function evaluations are done in parallel. The algorithm converges to the global optimum almost surely. The performance of this new algorithm, SO-MI, is compared to a branch and bound algorithm for nonlinear problems, a genetic algorithm, and the NOMAD (Nonsmooth Optimization by Mesh Adaptive Direct Search) algorithm for mixed-integer problems on 16 test problems from the literature (constrained, unconstrained, unimodal and multimodal problems), as well as on two application problems arising from structural optimization, and three application problems from optimal reliability design. The numerical experiments show that SO-MI reaches significantly better results than the other algorithms when the number of function evaluations is very restricted (200–300 evaluations). U2 - 10.1016/j.cor.2012.08.022 DO - 10.1016/j.cor.2012.08.022 M3 - Article VL - 40 SP - 1383 EP - 1400 JO - Computers and Operations Research JF - Computers and Operations Research SN - 0305-0548 IS - 5 ER - TY - JOUR T1 - Sparse source travel-time tomography of a laboratory target: accuracy and robustness of anomaly detection AU - Pursiainen, S. AU - Kaasalainen, M. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-17

Publisher name: Institute of Physics Publishing PY - 2014 Y1 - 2014 U2 - 10.1088/0266-5611/30/11/114016 DO - 10.1088/0266-5611/30/11/114016 M3 - Article VL - 30 SP - 1 EP - 19 JO - Inverse Problems JF - Inverse Problems SN - 0266-5611 IS - 11 M1 - 114016 ER - TY - JOUR T1 - Spectral study of the Eunomia family. I: Eunomia AU - Nathues, A. AU - Mottola, S. AU - Kaasalainen, M. AU - Neukum, G. N1 - Contribution: organisation=mat,FACT1=1 PY - 2005 Y1 - 2005 U2 - 10.1016/j.icarus.2004.12.013 DO - 10.1016/j.icarus.2004.12.013 M3 - Article VL - 175 SP - 452 EP - 463 JO - Icarus JF - Icarus SN - 0019-1035 ER - TY - JOUR T1 - Spin vectors in the Koronis family. II AU - Slivan, S. AU - Binzel, R.P. AU - Kaasalainen, M. AU - Hock, A. AU - Klesman, A. AU - Eckelman, L. AU - Stephens, R. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 U2 - 10.1016/j.icarus.2008.11.025 DO - 10.1016/j.icarus.2008.11.025 M3 - Article VL - 200 SP - 514 EP - 530 JO - Icarus JF - Icarus SN - 0019-1035 ER - TY - JOUR T1 - Stabilization to trajectories for parabolic equations AU - Phan, Duy AU - Rodrigues, Sérgio S. PY - 2018/6/1 Y1 - 2018/6/1 N2 - Both internal and boundary feedback exponential stabilization to trajectories for semilinear parabolic equations in a given bounded domain are addressed. The values of the controls are linear combinations of a finite number of actuators which are supported in a small region. A condition on the family of actuators is given which guarantees the local stabilizability of the control system. It is shown that a linearization-based Riccati feedback stabilizing controller can be constructed. The results of numerical simulations are presented and discussed. AB - Both internal and boundary feedback exponential stabilization to trajectories for semilinear parabolic equations in a given bounded domain are addressed. The values of the controls are linear combinations of a finite number of actuators which are supported in a small region. A condition on the family of actuators is given which guarantees the local stabilizability of the control system. It is shown that a linearization-based Riccati feedback stabilizing controller can be constructed. The results of numerical simulations are presented and discussed. KW - Feedback stabilization to trajectories KW - Semilinear parabolic equations U2 - 10.1007/s00498-018-0218-0 DO - 10.1007/s00498-018-0218-0 M3 - Article VL - 30 JO - Mathematics of Control Signals and Systems JF - Mathematics of Control Signals and Systems SN - 0932-4194 IS - 2 M1 - 11 ER - TY - JOUR T1 - Statistical Path Loss Parameter Estimation and Positioning using RSS Measurements AU - Nurminen, Henri AU - Talvitie, Jukka AU - Ali-Löytty, Simo AU - Muller, Philipp AU - Lohan, Elena-Simona AU - Piche, Robert AU - Renfors, Markku N1 - Contribution: organisation=elt,FACT1=0.35

Contribution: organisation=ase,FACT2=0.5

Contribution: organisation=mat,FACT3=0.15

Portfolio EDEND: 2014-08-20

Publisher name: Scientific Research Publishing PY - 2013 Y1 - 2013 M3 - Article VL - 12 SP - 13 EP - 27 JO - Journal of Global Positioning Systems JF - Journal of Global Positioning Systems SN - 1446-3156 IS - 1 ER - TY - JOUR T1 - Stock Price Dynamics and Option Valuations under Volatility Feedback Effect AU - Kanniainen, Juho AU - Piche, Robert N1 - Tallennettu Online First 2012:na.Final version published online 22 Dec 2012

Contribution: organisation=tta,FACT1=0.8

Contribution: organisation=mat,FACT2=0.2

Publisher name: Elsevier PY - 2013 Y1 - 2013 N2 - According to the volatility feedback effect, an unexpected increase in squared volatility leads to an immediate decline in the price-dividend ratio. In this paper, we consider the properties of stock price dynamics and option valuations under the volatility feedback effect by modeling the joint dynamics of stock price, dividends, and volatility in continuous time. Most importantly, our model predicts the negative effect of an increase in squared return volatility on the value of deep-in-the-money call options and, furthermore, attempts to explain the volatility puzzle. We theoretically demonstrate a mechanism by which the market price of diffusion return risk, or an equity risk-premium, affects option prices and empirically illustrate how to identify that mechanism using forward-looking information on option contracts. Our theoretical and empirical results support the relevance of the volatility feedback effect. Overall, the results indicate that the prevailing practice of ignoring the time-varying dividend yield in option pricing can lead to oversimplification of the stock market dynamics. AB - According to the volatility feedback effect, an unexpected increase in squared volatility leads to an immediate decline in the price-dividend ratio. In this paper, we consider the properties of stock price dynamics and option valuations under the volatility feedback effect by modeling the joint dynamics of stock price, dividends, and volatility in continuous time. Most importantly, our model predicts the negative effect of an increase in squared return volatility on the value of deep-in-the-money call options and, furthermore, attempts to explain the volatility puzzle. We theoretically demonstrate a mechanism by which the market price of diffusion return risk, or an equity risk-premium, affects option prices and empirically illustrate how to identify that mechanism using forward-looking information on option contracts. Our theoretical and empirical results support the relevance of the volatility feedback effect. Overall, the results indicate that the prevailing practice of ignoring the time-varying dividend yield in option pricing can lead to oversimplification of the stock market dynamics. U2 - 10.1016/j.physa.2012.10.004 DO - 10.1016/j.physa.2012.10.004 M3 - Article VL - 392 SP - 722 EP - 740 JO - Physica A: Statistical Mechanics and Its Applications JF - Physica A: Statistical Mechanics and Its Applications SN - 0378-4371 IS - 4 ER - TY - JOUR T1 - Stop it, and be stubborn! AU - Valmari, Antti PY - 2017/1/1 Y1 - 2017/1/1 N2 - This publication discusses how automatic verification of concurrent systems can be made more efficient by focusing on always may-terminating systems. First, making a system always may-terminating is a method formeeting a modelling need that exists independently of this publication. It is illustrated that without doing so, non-progress errors may be lost. Second, state explosion is often alleviated with stubborn, ample, and persistent set methods. They use expensive cycle or terminal strong component conditions in many cases. It is proven that for many important classes of properties, if the systems are always may-terminating, then these conditions can be left out. AB - This publication discusses how automatic verification of concurrent systems can be made more efficient by focusing on always may-terminating systems. First, making a system always may-terminating is a method formeeting a modelling need that exists independently of this publication. It is illustrated that without doing so, non-progress errors may be lost. Second, state explosion is often alleviated with stubborn, ample, and persistent set methods. They use expensive cycle or terminal strong component conditions in many cases. It is proven that for many important classes of properties, if the systems are always may-terminating, then these conditions can be left out. KW - Ignoring problem KW - Safety/progress/liveness properties KW - Stubborn set/ample set/persistent set/partial order methods U2 - 10.1145/3012279 DO - 10.1145/3012279 M3 - Article VL - 16 JO - ACM Transactions on Embedded Computing Systems JF - ACM Transactions on Embedded Computing Systems SN - 1539-9087 IS - 2 M1 - 46 ER - TY - JOUR T1 - Stress-strain behavior of polyamide 6 staple fibers of punch-needled press felts under simulated wet-pressing conditions AU - Hakala, Tomi AU - Kaleva, Osmo AU - Harlin, Ali N1 - Contribution: organisation=mol,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Publisher name: Routledge PY - 2012 Y1 - 2012 U2 - 10.1080/00405000.2012.677566 DO - 10.1080/00405000.2012.677566 M3 - Article VL - 103 SP - 1280 EP - 1293 JO - Journal of the Textile Institute JF - Journal of the Textile Institute SN - 0040-5000 IS - 12 ER - TY - JOUR T1 - Structural optimization of the pumping kite wind generator AU - Argatov, Ivan AU - Silvennoinen, Risto N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1007/s00158-009-0391-3 DO - 10.1007/s00158-009-0391-3 M3 - Article VL - 40 SP - 585 EP - 595 JO - Structural and Multidisciplinary Optimization JF - Structural and Multidisciplinary Optimization SN - 1615-147X IS - 1-6 ER - TY - JOUR T1 - Structure-Dynamics Relationships in Bursting Neuronal Networks Revealed Using a Prediction Framework AU - Mäki-Marttunen, Tuomo AU - Acimovic, Jugoslava AU - Linne, Marja-Leena AU - Ruohonen, Keijo N1 - Contribution: organisation=sgn,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Portfolio EDEND: 2013-12-29

Publisher name: Public Library of Science PY - 2013 Y1 - 2013 N2 - The question of how the structure of a neuronal network affects its functionality has gained a lot of attention in neuroscience. However, the vast majority of the studies on structure-dynamics relationships consider few types of network structures and assess limited numbers of structural measures. In this in silico study, we employ a wide diversity of network topologies and search among many possibilities the aspects of structure that have the greatest effect on the network excitability. The network activity is simulated using two point-neuron models, where the neurons are activated by noisy fluctuation of the membrane potential and their connections are described by chemical synapse models, and statistics on the number and quality of the emergent network bursts are collected for each network type. We apply a prediction framework to the obtained data in order to find out the most relevant aspects of network structure. In this framework, predictors that use different sets of graph-theoretic measures are trained to estimate the activity properties, such as burst count or burst length, of the networks. The performances of these predictors are compared with each other. We show that the best performance in prediction of activity properties for networks with sharp in-degree distribution is obtained when the prediction is based on clustering coefficient. By contrast, for networks with broad in-degree distribution, the maximum eigenvalue of the connectivity graph gives the most accurate prediction. The results shown for small (N~100) networks hold with few exceptions when different neuron models, different choices of neuron population and different average degrees are applied. We confirm our conclusions using larger (N~900) networks as well. Our findings reveal the relevance of different aspects of network structure from the viewpoint of network excitability, and our integrative method could serve as a general framework for structure-dynamics studies in biosciences. AB - The question of how the structure of a neuronal network affects its functionality has gained a lot of attention in neuroscience. However, the vast majority of the studies on structure-dynamics relationships consider few types of network structures and assess limited numbers of structural measures. In this in silico study, we employ a wide diversity of network topologies and search among many possibilities the aspects of structure that have the greatest effect on the network excitability. The network activity is simulated using two point-neuron models, where the neurons are activated by noisy fluctuation of the membrane potential and their connections are described by chemical synapse models, and statistics on the number and quality of the emergent network bursts are collected for each network type. We apply a prediction framework to the obtained data in order to find out the most relevant aspects of network structure. In this framework, predictors that use different sets of graph-theoretic measures are trained to estimate the activity properties, such as burst count or burst length, of the networks. The performances of these predictors are compared with each other. We show that the best performance in prediction of activity properties for networks with sharp in-degree distribution is obtained when the prediction is based on clustering coefficient. By contrast, for networks with broad in-degree distribution, the maximum eigenvalue of the connectivity graph gives the most accurate prediction. The results shown for small (N~100) networks hold with few exceptions when different neuron models, different choices of neuron population and different average degrees are applied. We confirm our conclusions using larger (N~900) networks as well. Our findings reveal the relevance of different aspects of network structure from the viewpoint of network excitability, and our integrative method could serve as a general framework for structure-dynamics studies in biosciences. U2 - 10.1371/journal.pone.0069373 DO - 10.1371/journal.pone.0069373 M3 - Article VL - 8 SP - 1 EP - 16 JO - PLoS ONE JF - PLoS ONE SN - 1932-6203 IS - 7 M1 - e69373 ER - TY - JOUR T1 - Structure-preserving mesh coupling based on the Buffa-Christiansen complex AU - Niemimäki, Ossi AU - Kurz, Stefan AU - Kettunen, Lauri PY - 2017 Y1 - 2017 N2 - The state of the art for mesh coupling at nonconforming interfaces is presented and reviewed. Mesh coupling is frequently applied to the modeling and simulation of motion in electromagnetic actuators and machines. The paper exploits Whitney elements to present the main ideas. Both interpolation- and projection-based methods are considered. In addition to accuracy and efficiency, we emphasize the question whether the schemes preserve the structure of the de Rham complex, which underlies Maxwell's equations. As a new contribution, a structure-preserving projection method is presented, in which Lagrange multiplier spaces are chosen from the Buffa-Christiansen complex. Its performance is compared with a straightforward interpolation based on Whitney and de Rham maps, and with Galerkin projection. AB - The state of the art for mesh coupling at nonconforming interfaces is presented and reviewed. Mesh coupling is frequently applied to the modeling and simulation of motion in electromagnetic actuators and machines. The paper exploits Whitney elements to present the main ideas. Both interpolation- and projection-based methods are considered. In addition to accuracy and efficiency, we emphasize the question whether the schemes preserve the structure of the de Rham complex, which underlies Maxwell's equations. As a new contribution, a structure-preserving projection method is presented, in which Lagrange multiplier spaces are chosen from the Buffa-Christiansen complex. Its performance is compared with a straightforward interpolation based on Whitney and de Rham maps, and with Galerkin projection. U2 - 10.1090/mcom/3121 DO - 10.1090/mcom/3121 M3 - Article VL - 86 SP - 507 EP - 524 JO - Mathematics of Computation JF - Mathematics of Computation SN - 0025-5718 ER - TY - JOUR T1 - Students’ motivations for social media enhanced studying and learning AU - Silius, Kirsi AU - Miilumäki, Thumas AU - Huhtamäki, Jukka AU - Tebest, Teemo AU - Meriläinen, Joonas AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat hyplab,FACT1=1 PY - 2010 Y1 - 2010 M3 - Article VL - 2 SP - 51 EP - 67 JO - Knowledge Management & E-Learning: An International Journal (KM&EL) JF - Knowledge Management & E-Learning: An International Journal (KM&EL) SN - 2073-7904 IS - 1 ER - TY - JOUR T1 - Studying the inertias of LCM matrices and revisiting the Bourque-Ligh conjecture AU - Haukkanen, Pentti AU - Mattila, Mika AU - Mäntysalo, Jori PY - 2020/4/1 Y1 - 2020/4/1 N2 - Let S={x1,x2,…,xn} be a finite set of distinct positive integers. Throughout this article we assume that the set S is GCD closed. The LCM matrix [S] of the set S is defined to be the n×n matrix with lcm(xi,xj) as its ij element. The famous Bourque-Ligh conjecture used to state that the LCM matrix of a GCD closed set S is always invertible, but currently it is a well-known fact that any nontrivial LCM matrix is indefinite and under the right circumstances it can be even singular (even if the set S is assumed to be GCD closed). However, not much more is known about the inertia of LCM matrices in general. The ultimate goal of this article is to improve this situation. Assuming that S is a meet closed set we define an entirely new lattice-theoretic concept by saying that an element xi∈S generates a double-chain set in S if the set meetcl(CS(xi))∖CS(xi) can be expressed as a union of two disjoint chains (here the set CS(xi) consists of all the elements of the set S that are covered by xi and meetcl(CS(xi)) is the smallest meet closed subset of S that contains the set CS(xi)). We then proceed by studying the values of the Möbius function on sets in which every element generates a double-chain set and use the properties of the Möbius function to explain why the Bourque-Ligh conjecture holds in so many cases and fails in certain very specific instances. After that we turn our attention to the inertia and see that in some cases it is possible to determine the inertia of an LCM matrix simply by looking at the lattice-theoretic structure of (S,|) alone. Finally, we are going to show how to construct LCM matrices in which the majority of the eigenvalues is either negative or positive. AB - Let S={x1,x2,…,xn} be a finite set of distinct positive integers. Throughout this article we assume that the set S is GCD closed. The LCM matrix [S] of the set S is defined to be the n×n matrix with lcm(xi,xj) as its ij element. The famous Bourque-Ligh conjecture used to state that the LCM matrix of a GCD closed set S is always invertible, but currently it is a well-known fact that any nontrivial LCM matrix is indefinite and under the right circumstances it can be even singular (even if the set S is assumed to be GCD closed). However, not much more is known about the inertia of LCM matrices in general. The ultimate goal of this article is to improve this situation. Assuming that S is a meet closed set we define an entirely new lattice-theoretic concept by saying that an element xi∈S generates a double-chain set in S if the set meetcl(CS(xi))∖CS(xi) can be expressed as a union of two disjoint chains (here the set CS(xi) consists of all the elements of the set S that are covered by xi and meetcl(CS(xi)) is the smallest meet closed subset of S that contains the set CS(xi)). We then proceed by studying the values of the Möbius function on sets in which every element generates a double-chain set and use the properties of the Möbius function to explain why the Bourque-Ligh conjecture holds in so many cases and fails in certain very specific instances. After that we turn our attention to the inertia and see that in some cases it is possible to determine the inertia of an LCM matrix simply by looking at the lattice-theoretic structure of (S,|) alone. Finally, we are going to show how to construct LCM matrices in which the majority of the eigenvalues is either negative or positive. KW - Bourque-Ligh conjecture KW - GCD matrix KW - LCM matrix KW - Smith determinant U2 - 10.1016/j.jcta.2019.105161 DO - 10.1016/j.jcta.2019.105161 M3 - Article VL - 171 JO - JOURNAL OF COMBINATORIAL THEORY SERIES A JF - JOURNAL OF COMBINATORIAL THEORY SERIES A SN - 0097-3165 M1 - 105161 ER - TY - JOUR T1 - Studying the various properties of MIN and MAX matrices - elementary vs. more advanced methods AU - Mattila, Mika AU - Haukkanen, Pentti PY - 2016/1 Y1 - 2016/1 N2 - Let T = {z1, z2, . . . , zn} be a finite multiset of real numbers, where z1 ≤ z2 ≤ · · · ≤ zn. The purpose of this article is to study the different properties of MIN and MAX matrices of the set T with min(zi , zj) and max(zi , zj) as their ij entries, respectively.We are going to do this by interpreting these matrices as so-called meet and join matrices and by applying some known results for meet and join matrices. Once the theorems are found with the aid of advanced methods, we also consider whether it would be possible to prove these same results by using elementary matrix methods only. In many cases the answer is positive. AB - Let T = {z1, z2, . . . , zn} be a finite multiset of real numbers, where z1 ≤ z2 ≤ · · · ≤ zn. The purpose of this article is to study the different properties of MIN and MAX matrices of the set T with min(zi , zj) and max(zi , zj) as their ij entries, respectively.We are going to do this by interpreting these matrices as so-called meet and join matrices and by applying some known results for meet and join matrices. Once the theorems are found with the aid of advanced methods, we also consider whether it would be possible to prove these same results by using elementary matrix methods only. In many cases the answer is positive. KW - MIN matrix KW - MAX matrix KW - meet matrix KW - join matrix U2 - 10.1515/spma-2016-0010 DO - 10.1515/spma-2016-0010 M3 - Article VL - 4 SP - 101 EP - 109 JO - Special Matrices JF - Special Matrices SN - 2300-7451 IS - 1 ER - TY - JOUR T1 - Supporting students to self-direct intentional learning projects with social media AU - Väljataga, T. AU - Fiedler, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 M3 - Article VL - 12 SP - 58 EP - 69 JO - Journal of Educational Technology and Society JF - Journal of Educational Technology and Society SN - 1436-4522 IS - 3 ER - TY - JOUR T1 - Teachers' perspectives on project-based learning in mathematics and science AU - Viro, Elina AU - Lehtonen, Daranee AU - Joutsenlahti, Jorma AU - Tahvanainen, Ville PY - 2020 Y1 - 2020 M3 - Article VL - 8 SP - 12 EP - 31 JO - European Journal of Science and Mathematics Education JF - European Journal of Science and Mathematics Education SN - 2301-251X IS - 1 ER - TY - JOUR T1 - Teleconsultation: Changes in technology and costs over a 12-year period AU - Lamminen, Johanna AU - Forsvik, Heikki Johan AU - Voipio, Ville AU - Ruohonen, Keijo N1 - Contribution: organisation=sgn,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5 PY - 2011 Y1 - 2011 U2 - 10.1258/jtt.2011.110211 DO - 10.1258/jtt.2011.110211 M3 - Article VL - 17 SP - 412 EP - 416 JO - Journal of Telemedicine and Telecare JF - Journal of Telemedicine and Telecare SN - 1357-633X IS - 8 ER - TY - JOUR T1 - Terrestrial laser scanning for non-destructive estimates of liana stem biomass AU - Krishna Moorthy, Sruthi M. AU - Raumonen, Pasi AU - Van den Bulcke, Jan AU - Calders, Kim AU - Verbeeck, Hans PY - 2020/1/15 Y1 - 2020/1/15 N2 - Lianas are important and yet understudied components of tropical forests. Recent studies have shown that lianas are increasing in abundance and biomass in neotropical forests. However, aboveground biomass estimates of lianas are highly uncertain when calculated from allometric relations. This is mainly because of the limited sample size, especially for large lianas, used to construct the allometric models. Furthermore, the allometry of lianas can be weakly constrained mechanically throughout its development from sapling to mature form. In this study, we propose to extract liana stem biomass from terrestrial laser scanning (TLS) data of tropical forests. We show good agreement with a concordance correlation coefficient (CCC) of 0.94 between the TLS-derived volume to reference volume from eleven synthetic lianas. We also compare the TLS-derived biomass for ten real lianas in Nouragues, French Guiana, with the biomass derived from all existing allometric equations for lianas. Our results show relatively low CCC values for all the allometric models with the most commonly used pantropical model overestimating the total biomass by up to 133% compared to the TLS-derived biomass. Our study not only facilitates the testing of allometric equations but also enables non-destructive estimation of liana stem biomass. Since lianas are disturbance-adapted plants, liana abundance is likely to increase with increased forest disturbance. Our method will facilitate the long-term monitoring of liana biomass change in regenerating forests after disturbance, which is critical for developing effective forest management strategies. AB - Lianas are important and yet understudied components of tropical forests. Recent studies have shown that lianas are increasing in abundance and biomass in neotropical forests. However, aboveground biomass estimates of lianas are highly uncertain when calculated from allometric relations. This is mainly because of the limited sample size, especially for large lianas, used to construct the allometric models. Furthermore, the allometry of lianas can be weakly constrained mechanically throughout its development from sapling to mature form. In this study, we propose to extract liana stem biomass from terrestrial laser scanning (TLS) data of tropical forests. We show good agreement with a concordance correlation coefficient (CCC) of 0.94 between the TLS-derived volume to reference volume from eleven synthetic lianas. We also compare the TLS-derived biomass for ten real lianas in Nouragues, French Guiana, with the biomass derived from all existing allometric equations for lianas. Our results show relatively low CCC values for all the allometric models with the most commonly used pantropical model overestimating the total biomass by up to 133% compared to the TLS-derived biomass. Our study not only facilitates the testing of allometric equations but also enables non-destructive estimation of liana stem biomass. Since lianas are disturbance-adapted plants, liana abundance is likely to increase with increased forest disturbance. Our method will facilitate the long-term monitoring of liana biomass change in regenerating forests after disturbance, which is critical for developing effective forest management strategies. KW - Liana biomass KW - Quantitative structure models KW - Terrestrial laser scanning KW - Total forest biomass KW - Tropical forests U2 - 10.1016/j.foreco.2019.117751 DO - 10.1016/j.foreco.2019.117751 M3 - Article VL - 456 JO - FOREST ECOLOGY AND MANAGEMENT JF - FOREST ECOLOGY AND MANAGEMENT SN - 0378-1127 M1 - 117751 ER - TY - JOUR T1 - The arithmetic Jacobian matrix and determinant AU - Haukkanen, Pentti AU - Merikoski, Jorma K. AU - Mattila, Mika AU - Tossavainen, Timo PY - 2017 Y1 - 2017 N2 - Let α1,…, αm be such real numbers that can be expressed as a finite product of prime powers with rational exponents. Using arithmetic partial derivatives, we define the arithmetic Jacobian matrix Ja of the vector a = (α1,…, αm) analogously to the Jacobian matrix Jf of a vector function f. We introduce the concept of multiplicative independence of {α1,…, αm} and show that Ja plays in it a similar role as Jf does in functional independence. We also present a kind of arithmetic implicit function 1 theorem and show that Ja applies to it somewhat analogouslytheorem and show that Ja applies to it somewhat analogously as Jf applies to the ordinary implicit function theorem. AB - Let α1,…, αm be such real numbers that can be expressed as a finite product of prime powers with rational exponents. Using arithmetic partial derivatives, we define the arithmetic Jacobian matrix Ja of the vector a = (α1,…, αm) analogously to the Jacobian matrix Jf of a vector function f. We introduce the concept of multiplicative independence of {α1,…, αm} and show that Ja plays in it a similar role as Jf does in functional independence. We also present a kind of arithmetic implicit function 1 theorem and show that Ja applies to it somewhat analogouslytheorem and show that Ja applies to it somewhat analogously as Jf applies to the ordinary implicit function theorem. KW - Arithmetic derivative KW - Arithmetic partial derivative KW - Implicit function theorem KW - Jacobian determinant KW - Jacobian matrix KW - Multiplicative independence M3 - Article VL - 20 JO - Journal of Integer Sequences JF - Journal of Integer Sequences SN - 1530-7638 IS - 9 M1 - 17.9.2 ER - TY - JOUR T1 - The Cauchy-Schwarz inequality in Cayley graph and tournament structures on finite fields AU - Foldes, Stephan AU - Major, Laszlo N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2015-01-21

Publisher name: Miskolci Egyetem PY - 2014 Y1 - 2014 M3 - Article VL - 15 SP - 153 EP - 158 JO - Miskolc Mathematical Notes JF - Miskolc Mathematical Notes SN - 1787-2405 IS - 1 ER - TY - JOUR T1 - The complementarity of astrometric and radial velocity exoplanet observations. Determining exoplanet mass with astrometric snapshots. AU - Tuomi, M. AU - Kotiranta, S. AU - Kaasalainen, M. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 U2 - 10.1051/0004-6361:200810288 DO - 10.1051/0004-6361:200810288 M3 - Article VL - 494 SP - 769 EP - 774 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 ER - TY - JOUR T1 - The effect of hardware-computed travel time on localization accuracy in the inversion of experimental (acoustic) waveform data AU - Takala, Mika AU - Hämäläinen, Timo AU - Pursiainen, Sampsa PY - 2017/6 Y1 - 2017/6 N2 - This study aims to advance hardware-level computations for travel-time tomography applications in which the wavelength is close to the diameter of the information that has to be recovered. Such can be the case, for example, in the imaging applications of 1) biomedical physics; 2) astrogeophysics; and 3) civil engineering. Our aim is to shed light on the effect of that preprocessing the digital waveform signal has on the inversion results and to find computational solutions that guarantee robust inversion when there are incomplete and/or noisy measurements. We describe a hardware-level implementation for integrated and thresholded travel-time computation (ITT and TTT). We compare the ITT and TTT approaches in inversion analysis with experimental acoustic travel-time data recorded using a ring geometry for the transmission and measurement points. The results obtained suggest that ITT is essential for maintaining the robustness of the inversion with imperfect signal digitization and sparsity. In order to ensure the relevance of the results, the specifications of the test setup were related to those of applications 1-3. AB - This study aims to advance hardware-level computations for travel-time tomography applications in which the wavelength is close to the diameter of the information that has to be recovered. Such can be the case, for example, in the imaging applications of 1) biomedical physics; 2) astrogeophysics; and 3) civil engineering. Our aim is to shed light on the effect of that preprocessing the digital waveform signal has on the inversion results and to find computational solutions that guarantee robust inversion when there are incomplete and/or noisy measurements. We describe a hardware-level implementation for integrated and thresholded travel-time computation (ITT and TTT). We compare the ITT and TTT approaches in inversion analysis with experimental acoustic travel-time data recorded using a ring geometry for the transmission and measurement points. The results obtained suggest that ITT is essential for maintaining the robustness of the inversion with imperfect signal digitization and sparsity. In order to ensure the relevance of the results, the specifications of the test setup were related to those of applications 1-3. U2 - 10.1109/TCI.2017.2686698 DO - 10.1109/TCI.2017.2686698 M3 - Article VL - 3 SP - 344 EP - 354 JO - IEEE Transactions on Computational Imaging JF - IEEE Transactions on Computational Imaging SN - 2333-9403 IS - 2 ER - TY - JOUR T1 - The Graph Curvature Calculator and the curvatures of cubic graphs AU - Cushing, David AU - Kangaslampi, Riikka AU - Lipiäinen, Valtteri AU - Liu, Shiping AU - Stagg, George W. PY - 2019/9/14 Y1 - 2019/9/14 N2 - We classify all cubic graphs with either non-negative Ollivier-Ricci curvature or non-negative Bakry-Émery curvature everywhere. We show in both curvature notions that the non-negatively curved graphs are the prism graphs and the Möbius ladders. We also highlight an online tool for calculating the curvature of graphs under several variants of these curvature notions that we use in the classification. As a consequence of the classification result we show, that non-negatively curved cubic expanders do not exist. AB - We classify all cubic graphs with either non-negative Ollivier-Ricci curvature or non-negative Bakry-Émery curvature everywhere. We show in both curvature notions that the non-negatively curved graphs are the prism graphs and the Möbius ladders. We also highlight an online tool for calculating the curvature of graphs under several variants of these curvature notions that we use in the classification. As a consequence of the classification result we show, that non-negatively curved cubic expanders do not exist. U2 - 10.1080/10586458.2019.1660740 DO - 10.1080/10586458.2019.1660740 M3 - Article JO - Experimental Mathematics JF - Experimental Mathematics SN - 1058-6458 ER - TY - JOUR T1 - The impact crater at the origin of the Julia family detected with VLT/SPHERE? AU - Vernazza, P. AU - Broz, M. AU - Drouard, A. AU - Hanuš, J. AU - Viikinkoski, M. AU - Marsset, M. AU - Jorda, L. AU - Fetick, R. AU - Carry, B. AU - Marchis, F. AU - Birlan, M. AU - Fusco, T. AU - Santana-Ros, T. AU - Podlewska-Gaca, E. AU - Jehin, E. AU - Ferrais, M. AU - Bartczak, P. AU - Dudziński, G. AU - Berthier, J. AU - Castillo-Rogez, J. AU - Cipriani, F. AU - Colas, F. AU - Dumas, C. AU - Urech, J. AU - Kaasalainen, M. AU - Kryszczynska, A. AU - Lamy, P. AU - Le Coroller, H. AU - Marciniak, A. AU - Michalowski, T. AU - Michel, P. AU - Pajuelo, M. AU - Tanga, P. AU - Vachier, F. AU - Vigan, A. AU - Warner, B. AU - Witasse, O. AU - Yang, B. AU - Asphaug, E. AU - Richardson, D. C. AU - Ševeček, P. AU - Gillon, M. AU - Benkhaldoun, Z. PY - 2018/10/1 Y1 - 2018/10/1 N2 - Context. The vast majority of the geophysical and geological constraints (e.g., internal structure, cratering history) for main-belt asteroids have so far been obtained via dedicated interplanetary missions (e.g., ESA Rosetta, NASA Dawn). The high angular resolution of SPHERE/ZIMPOL, the new-generation visible adaptive-optics camera at ESO VLT, implies that these science objectives can now be investigated from the ground for a large fraction of D 100 km main-belt asteroids. The sharp images acquired by this instrument can be used to accurately constrain the shape and thus volume of these bodies (hence density when combined with mass estimates) and to characterize the distribution and topography of D 30 km craters across their surfaces. Aims. Here, via several complementary approaches, we evaluated the recently proposed hypothesis that the S-type asteroid (89) Julia is the parent body of a small compact asteroid family that formed via a cratering collisional event. Methods. We observed (89) Julia with VLT/SPHERE/ZIMPOL throughout its rotation, derived its 3D shape, and performed a reconnaissance and characterization of the largest craters. We also performed numerical simulations to first confirm the existence of the Julia family and to determine its age and the size of the impact crater at its origin. Finally, we utilized the images/3D shape in an attempt to identify the origin location of the small collisional family. Results. On the one hand, our VLT/SPHERE observations reveal the presence of a large crater (D 75 km) in Julias southern hemisphere. On the other hand, our numerical simulations suggest that (89) Julia was impacted 30-120 Myrs ago by a D 8 km asteroid, thereby creating a D 60 km impact crater at the surface of Julia. Given the small size of the impactor, the obliquity of Julia and the particular orientation of the family in the (a,i) space, the imaged impact crater is likely to be the origin of the family. Conclusions. New doors into ground-based asteroid exploration, namely, geophysics and geology, are being opened thanks to the unique capabilities of VLT/SPHERE. Also, the present work may represent the beginning of a new era of asteroid-family studies. In the fields of geophysics, geology, and asteroid family studies, the future will only get brighter with the forthcoming arrival of 30-40 m class telescopes like ELT, TMT, and GMT. AB - Context. The vast majority of the geophysical and geological constraints (e.g., internal structure, cratering history) for main-belt asteroids have so far been obtained via dedicated interplanetary missions (e.g., ESA Rosetta, NASA Dawn). The high angular resolution of SPHERE/ZIMPOL, the new-generation visible adaptive-optics camera at ESO VLT, implies that these science objectives can now be investigated from the ground for a large fraction of D 100 km main-belt asteroids. The sharp images acquired by this instrument can be used to accurately constrain the shape and thus volume of these bodies (hence density when combined with mass estimates) and to characterize the distribution and topography of D 30 km craters across their surfaces. Aims. Here, via several complementary approaches, we evaluated the recently proposed hypothesis that the S-type asteroid (89) Julia is the parent body of a small compact asteroid family that formed via a cratering collisional event. Methods. We observed (89) Julia with VLT/SPHERE/ZIMPOL throughout its rotation, derived its 3D shape, and performed a reconnaissance and characterization of the largest craters. We also performed numerical simulations to first confirm the existence of the Julia family and to determine its age and the size of the impact crater at its origin. Finally, we utilized the images/3D shape in an attempt to identify the origin location of the small collisional family. Results. On the one hand, our VLT/SPHERE observations reveal the presence of a large crater (D 75 km) in Julias southern hemisphere. On the other hand, our numerical simulations suggest that (89) Julia was impacted 30-120 Myrs ago by a D 8 km asteroid, thereby creating a D 60 km impact crater at the surface of Julia. Given the small size of the impactor, the obliquity of Julia and the particular orientation of the family in the (a,i) space, the imaged impact crater is likely to be the origin of the family. Conclusions. New doors into ground-based asteroid exploration, namely, geophysics and geology, are being opened thanks to the unique capabilities of VLT/SPHERE. Also, the present work may represent the beginning of a new era of asteroid-family studies. In the fields of geophysics, geology, and asteroid family studies, the future will only get brighter with the forthcoming arrival of 30-40 m class telescopes like ELT, TMT, and GMT. KW - Methods: numerical KW - Methods: observational KW - Minor planets asteroids: individual: (89) Julia KW - Techniques: high angular resolution U2 - 10.1051/0004-6361/201833477 DO - 10.1051/0004-6361/201833477 M3 - Article VL - 618 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - 33477 ER - TY - JOUR T1 - The Internal Model Principle for Systems with Unbounded Control and Observation AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-31

Publisher name: Society for Industrial and Applied Mathematics PY - 2014 Y1 - 2014 U2 - 10.1137/130921362 DO - 10.1137/130921362 M3 - Article VL - 52 SP - 3967 EP - 4000 JO - SIAM Journal on Control and Optimization JF - SIAM Journal on Control and Optimization SN - 0363-0129 IS - 6 ER - TY - JOUR T1 - The Kraft Sum as a Monotone Function of the Refinement-Ordered Set of Uniquely Decipherable Codes AU - Foldes, Stephan N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-11-29

Publisher name: Institute of Mathematics. Brno University of Technology PY - 2013 Y1 - 2013 M3 - Article VL - 2 SP - 1 EP - 4 JO - Mathematics for Applications JF - Mathematics for Applications SN - 1805-3610 IS - 1 ER - TY - JOUR T1 - The puzzling mutual orbit of the binary Trojan asteroid (624) Hektor AU - Marchis, F. AU - Durech, J. AU - Castillo-Rogez, J. AU - Vachier, F. AU - Cuk, M. AU - Berthier, J. AU - Wong, M.H. AU - Kalas, P. AU - Duchene, G. AU - Van Dam, M.A. AU - Hamanowa, H. AU - Viikinkoski, M. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2015-01-13

Publisher name: Institute of Physics Publishing Ltd. PY - 2014 Y1 - 2014 U2 - 10.1088/2041-8205/783/2/L37 DO - 10.1088/2041-8205/783/2/L37 M3 - Article VL - 783 JO - Astrophysical Journal Letters JF - Astrophysical Journal Letters SN - 2041-8205 IS - 2 ER - TY - JOUR T1 - The Resolved Asteroid Program – Size, shape, and pole of (52) Europa AU - Merline, W.J. AU - Drummond, J.D. AU - Carry, B. AU - Conrad, A. AU - Tamblyn, P.M. AU - Dumas, C. AU - Kaasalainen, M. AU - Erikson, A. AU - Mottola, S. AU - Durech, J. AU - Rousseau, G. AU - Behrend, R. AU - Casalnuovo, G.B. AU - Chinaglia, B. AU - Christou, J.C. AU - Chapman, C.R. AU - Neyman, C. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: Academic Press PY - 2013 Y1 - 2013 U2 - 10.1016/j.icarus.2013.01.010 DO - 10.1016/j.icarus.2013.01.010 M3 - Article VL - 225 SP - 794 EP - 805 JO - Icarus JF - Icarus SN - 0019-1035 IS - 1 ER - TY - JOUR T1 - Thermal infrared observations of the Hayabusa spacecraft target asteroid 25143 Itokawa AU - Mueller, T.G. AU - Sekiguchi, T. AU - Kaasalainen, M. AU - Abe, M. AU - Hasegawa, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2005 Y1 - 2005 U2 - 10.1051/0004-6361:20053862 DO - 10.1051/0004-6361:20053862 M3 - Article VL - 443 SP - 347 EP - 355 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 ER - TY - JOUR T1 - Thermal properties of asteroid 21 Lutetia from Spitzer Space Telescope observations AU - Lamy, P. AU - Groussin, O. AU - Fornasier, S. AU - Jorda, L. AU - Kaasalainen, Mikko AU - Barucci, M. N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1051/0004-6361/201014361 DO - 10.1051/0004-6361/201014361 M3 - Article VL - 516 SP - 1 EP - 10 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 IS - A74 ER - TY - JOUR T1 - The Role of Exosystems in Output Regulation AU - Paunonen, Lassi N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-10-20

Publisher name: IEEE PY - 2014 Y1 - 2014 U2 - 10.1109/TAC.2014.2303214 DO - 10.1109/TAC.2014.2303214 M3 - Article VL - 59 SP - 2301 EP - 2305 JO - IEEE Transactions on Automatic Control JF - IEEE Transactions on Automatic Control SN - 0018-9286 IS - 8 ER - TY - JOUR T1 - The shape and rotation of asteroid 2008 TC3 AU - Scheirich, Peter AU - Durech, Josef AU - Pravec, Petr AU - Kozubal, Marek AU - Dantowitz, Ron AU - Kaasalainen, Mikko AU - Betzler, Alberto Silva AU - Beltrame, Paolo AU - Muler, Gustavo AU - Birtwhistle, Peter AU - Kugel, Francois N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1111/j.1945-5100.2010.01146.x DO - 10.1111/j.1945-5100.2010.01146.x M3 - Article VL - 45 SP - 1804 EP - 1811 JO - Meteoritics and Planetary Science JF - Meteoritics and Planetary Science SN - 1086-9379 IS - 10-11 ER - TY - JOUR T1 - The shape of (7) Iris as evidence of an ancient large impact? AU - Hanuš, J. AU - Marsset, M. AU - Vernazza, P. AU - Viikinkoski, M. AU - Drouard, A. AU - Broa, M. AU - Carry, B. AU - Fetick, R. AU - Marchis, F. AU - Jorda, L. AU - Fusco, T. AU - Birlan, M. AU - Santana-Ros, T. AU - Podlewska-Gaca, E. AU - Jehin, E. AU - Ferrais, M. AU - Grice, J. AU - Bartczak, P. AU - Berthier, J. AU - Castillo-Rogez, J. AU - Cipriani, F. AU - Colas, F. AU - Dudziński, G. AU - Dumas, C. AU - Äž Urech, J. AU - Kaasalainen, M. AU - Kryszczynska, A. AU - Lamy, P. AU - Le Coroller, H. AU - Marciniak, A. AU - Michalowski, T. AU - Michel, P. AU - Pajuelo, M. AU - Tanga, P. AU - Vachier, F. AU - Vigan, A. AU - Witasse, O. AU - Yang, B. PY - 2019/4/1 Y1 - 2019/4/1 N2 - Context. Asteroid (7) Iris is an ideal target for disk-resolved imaging owing to its brightness (V ~ 7-8) and large angular size of 0.33′′ during its apparitions. Iris is believed to belong to the category of large unfragmented asteroids that avoided internal differentiation, implying that its current shape and topography may record the first few 100 Myr of the solar system's collisional evolution. Aims. We recovered information about the shape and surface topography of Iris from disk-resolved VLT/SPHERE/ZIMPOL images acquired in the frame of our ESO large program. Methods. We used the All-Data Asteroid Modeling (ADAM) shape reconstruction algorithm to model the 3D shape of Iris, using optical disk-integrated data and disk-resolved images from SPHERE and earlier AO systems as inputs. We analyzed the SPHERE images and our model to infer the asteroid's global shape and the morphology of its main craters. Results. We present the 3D shape, volume-equivalent diameter D eq = 214 ± 5 km, and bulk density ρ = 2.7 ± 0.3 g cm -3 of Iris. Its shape appears to be consistent with that of an oblate spheroid with a large equatorial excavation. We identified eight putative surface features 20-40 km in diameter detected at several epochs, which we interpret as impact craters, and several additional crater candidates. Craters on Iris have depth-To-diameter ratios that are similar to those of analogous 10 km craters on Vesta. Conclusions. The bulk density of Iris is consistent with that of its meteoritic analog based on spectroscopic observations, namely LL ordinary chondrites. Considering the absence of a collisional family related to Iris and the number of large craters on its surface, we suggest that its equatorial depression may be the remnant of an ancient (at least 3 Gyr) impact. Iris's shape further opens the possibility that large planetesimals formed as almost perfect oblate spheroids. Finally, we attribute the difference in crater morphology between Iris and Vesta to their different surface gravities, and the absence of a substantial impact-induced regolith on Iris. AB - Context. Asteroid (7) Iris is an ideal target for disk-resolved imaging owing to its brightness (V ~ 7-8) and large angular size of 0.33′′ during its apparitions. Iris is believed to belong to the category of large unfragmented asteroids that avoided internal differentiation, implying that its current shape and topography may record the first few 100 Myr of the solar system's collisional evolution. Aims. We recovered information about the shape and surface topography of Iris from disk-resolved VLT/SPHERE/ZIMPOL images acquired in the frame of our ESO large program. Methods. We used the All-Data Asteroid Modeling (ADAM) shape reconstruction algorithm to model the 3D shape of Iris, using optical disk-integrated data and disk-resolved images from SPHERE and earlier AO systems as inputs. We analyzed the SPHERE images and our model to infer the asteroid's global shape and the morphology of its main craters. Results. We present the 3D shape, volume-equivalent diameter D eq = 214 ± 5 km, and bulk density ρ = 2.7 ± 0.3 g cm -3 of Iris. Its shape appears to be consistent with that of an oblate spheroid with a large equatorial excavation. We identified eight putative surface features 20-40 km in diameter detected at several epochs, which we interpret as impact craters, and several additional crater candidates. Craters on Iris have depth-To-diameter ratios that are similar to those of analogous 10 km craters on Vesta. Conclusions. The bulk density of Iris is consistent with that of its meteoritic analog based on spectroscopic observations, namely LL ordinary chondrites. Considering the absence of a collisional family related to Iris and the number of large craters on its surface, we suggest that its equatorial depression may be the remnant of an ancient (at least 3 Gyr) impact. Iris's shape further opens the possibility that large planetesimals formed as almost perfect oblate spheroids. Finally, we attribute the difference in crater morphology between Iris and Vesta to their different surface gravities, and the absence of a substantial impact-induced regolith on Iris. KW - Methods: numerical KW - Methods: observational KW - Minor planets, asteroids: individual: 7 Iris U2 - 10.1051/0004-6361/201834541 DO - 10.1051/0004-6361/201834541 M3 - Article VL - 624 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A121 ER - TY - JOUR T1 - The StarT Project Competition from the Perspective of Mathematics and Academic Literacy AU - Viro, Elina AU - Joutsenlahti, Jorma PY - 2018/5/4 Y1 - 2018/5/4 N2 - This article concerns mathematical project work in the context of Finnish StarT project competition. The focus is on how well pupils achieve the learning objective of their project work: learning mathematics and practicing 21st century skills. Development of the learning objectives is considered from the viewpoint of Finnish national core curriculum and evaluated using the framework of academic literacy. The research material consists of teams’ project reports, observation, and questionnaires. Project work in the StarT competition seems to develop the learning objectives of project-based learning: pupils practice 21st century skills while studying mathematical contents. AB - This article concerns mathematical project work in the context of Finnish StarT project competition. The focus is on how well pupils achieve the learning objective of their project work: learning mathematics and practicing 21st century skills. Development of the learning objectives is considered from the viewpoint of Finnish national core curriculum and evaluated using the framework of academic literacy. The research material consists of teams’ project reports, observation, and questionnaires. Project work in the StarT competition seems to develop the learning objectives of project-based learning: pupils practice 21st century skills while studying mathematical contents. KW - project-based learning KW - academic literacy KW - Mathematics KW - Education U2 - 10.3390/educsci8020067 DO - 10.3390/educsci8020067 M3 - Article VL - 8 JO - EDUCATION SCIENCES JF - EDUCATION SCIENCES SN - 2227-7102 IS - 2 ER - TY - JOUR T1 - Tiedonlouhintaa tieliikenneonnettomuussatasta AU - Turunen, Esko N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-09-30

Publisher name: Liikennesuunnittelun Seura ry PY - 2013 Y1 - 2013 M3 - Article VL - 31 SP - 7 EP - 8 JO - Liikenne JF - Liikenne SN - 0359-9345 IS - 2 ER - TY - JOUR T1 - Tomographic inversion of gravity gradient field for a synthetic Itokawa model AU - Sorsa, Liisa-Ida AU - Takala, Mika AU - Bambach, Patrick AU - Deller, Jakob AU - Vilenius, Esa AU - Agarwal, Jessica AU - Carroll, Kieran A. AU - Karatekin, Özgür AU - Pursiainen, Sampsa PY - 2020/1/15 Y1 - 2020/1/15 N2 - This article investigates reconstructing the internal mass density of a numerical asteroid model using the gradient of a simulated gravity field as synthetic measurement data. Our goal is to advance the mathematical inversion methodology and find feasibility constraints for the resolution, noise and orbit selection for future space missions. We base our model on the shape of the asteroid Itokawa as well as on the recent observations and simulation studies which suggest that the internal density varies, increasing towards the center, and that the asteroid may have a detailed structure. We introduce randomized multiresolution scan algorithm which might provide a robust way to cancel out bias and artifact effects related to the measurement noise and numerical discretization. In this scheme, the inverse algorithm can reconstruct details of various sizes without fixing the exact resolution a priori, and the randomization minimizes the effect of discretization on the solution. We show that the adopted methodology provides an advantageous way to diminish the surface bias of the inverse solution. The results also suggest that a noise level below 80 Eotvos will be sufficient for the detection of internal voids and high density anomalies, if a sparse set of measurements can be obtained from a close-enough distance to the target. AB - This article investigates reconstructing the internal mass density of a numerical asteroid model using the gradient of a simulated gravity field as synthetic measurement data. Our goal is to advance the mathematical inversion methodology and find feasibility constraints for the resolution, noise and orbit selection for future space missions. We base our model on the shape of the asteroid Itokawa as well as on the recent observations and simulation studies which suggest that the internal density varies, increasing towards the center, and that the asteroid may have a detailed structure. We introduce randomized multiresolution scan algorithm which might provide a robust way to cancel out bias and artifact effects related to the measurement noise and numerical discretization. In this scheme, the inverse algorithm can reconstruct details of various sizes without fixing the exact resolution a priori, and the randomization minimizes the effect of discretization on the solution. We show that the adopted methodology provides an advantageous way to diminish the surface bias of the inverse solution. The results also suggest that a noise level below 80 Eotvos will be sufficient for the detection of internal voids and high density anomalies, if a sparse set of measurements can be obtained from a close-enough distance to the target. KW - Asteroid Itokawa KW - Geophysical techniques KW - Interiors U2 - 10.1016/j.icarus.2019.113425 DO - 10.1016/j.icarus.2019.113425 M3 - Article VL - 336 JO - Icarus JF - Icarus SN - 0019-1035 M1 - 113425 ER - TY - JOUR T1 - Topics on hyperbolic function theory in geometric algebra with a positive signature AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - Poistetu tupla r=3013

Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Article VL - 10 SP - 249 EP - 263 JO - Computational Methods in Function Theory JF - Computational Methods in Function Theory SN - 1617-9447 IS - 1 ER - TY - JOUR T1 - Towards a unified framework for decomposability of processes AU - Lahtinen, Valtteri AU - Stenvall, Antti PY - 2016 Y1 - 2016 N2 - The concept of process is ubiquitous in science, engineering and everyday life. Category theory, and monoidal categories in particular, provide an abstract framework for modelling processes of many kinds. In this paper, we concentrate on sequential and parallel decomposability of processes in the framework of monoidal categories: We will give a precise definition, what it means for processes to be decomposable. Moreover, through examples, we argue that viewing parallel processes as coupled in this framework can be seen as a category mistake or a misinterpretation. We highlight the suitability of category theory for a structuralistic interpretation of mathematical modelling and argue that for appliers of mathematics, such as engineers, there is a pragmatic advantage from this. AB - The concept of process is ubiquitous in science, engineering and everyday life. Category theory, and monoidal categories in particular, provide an abstract framework for modelling processes of many kinds. In this paper, we concentrate on sequential and parallel decomposability of processes in the framework of monoidal categories: We will give a precise definition, what it means for processes to be decomposable. Moreover, through examples, we argue that viewing parallel processes as coupled in this framework can be seen as a category mistake or a misinterpretation. We highlight the suitability of category theory for a structuralistic interpretation of mathematical modelling and argue that for appliers of mathematics, such as engineers, there is a pragmatic advantage from this. U2 - 10.1007/s11229-016-1139-4 DO - 10.1007/s11229-016-1139-4 M3 - Article VL - 194 SP - 4411 EP - 4427 JO - SYNTHESE JF - SYNTHESE SN - 0039-7857 IS - 11 ER - TY - JOUR T1 - Tree biomass equations from terrestrial LiDAR T2 - A case study in Guyana AU - Lau, Alvaro AU - Calders, Kim AU - Bartholomeus, Harm AU - Martius, Christopher AU - Raumonen, Pasi AU - Herold, Martin AU - Vicari, Matheus AU - Sukhdeo, Hansrajie AU - Singh, Jeremy AU - Goodman, Rosa C. PY - 2019/6/1 Y1 - 2019/6/1 N2 - Large uncertainties in tree and forest carbon estimates weaken national efforts to accurately estimate aboveground biomass (AGB) for their national monitoring, measurement, reporting and verification system. Allometric equations to estimate biomass have improved, but remain limited. They rely on destructive sampling; large trees are under-represented in the data used to create them; and they cannot always be applied to different regions. These factors lead to uncertainties and systematic errors in biomass estimations. We developed allometric models to estimate tree AGB in Guyana. These models were based on tree attributes (diameter, height, crown diameter) obtained from terrestrial laser scanning (TLS) point clouds from 72 tropical trees and wood density. We validated our methods and models with data from 26 additional destructively harvested trees. We found that our best TLS-derived allometric models included crown diameter, provided more accurate AGB estimates (R2 = 0.92-0.93) than traditional pantropical models (R2 = 0.85-0.89), and were especially accurate for large trees (diameter > 70 cm). The assessed pantropical models underestimated AGB by 4 to 13%. Nevertheless, one pantropical model (Chave et al. 2005 without height) consistently performed best among the pantropical models tested (R2 = 0.89) and predicted AGB accurately across all size classes-which but for this could not be known without destructive or TLS-derived validation data. Our methods also demonstrate that tree height is difficult to measure in situ, and the inclusion of height in allometric models consistently worsened AGB estimates. We determined that TLS-derived AGB estimates were unbiased. Our approach advances methods to be able to develop, test, and choose allometric models without the need to harvest trees. AB - Large uncertainties in tree and forest carbon estimates weaken national efforts to accurately estimate aboveground biomass (AGB) for their national monitoring, measurement, reporting and verification system. Allometric equations to estimate biomass have improved, but remain limited. They rely on destructive sampling; large trees are under-represented in the data used to create them; and they cannot always be applied to different regions. These factors lead to uncertainties and systematic errors in biomass estimations. We developed allometric models to estimate tree AGB in Guyana. These models were based on tree attributes (diameter, height, crown diameter) obtained from terrestrial laser scanning (TLS) point clouds from 72 tropical trees and wood density. We validated our methods and models with data from 26 additional destructively harvested trees. We found that our best TLS-derived allometric models included crown diameter, provided more accurate AGB estimates (R2 = 0.92-0.93) than traditional pantropical models (R2 = 0.85-0.89), and were especially accurate for large trees (diameter > 70 cm). The assessed pantropical models underestimated AGB by 4 to 13%. Nevertheless, one pantropical model (Chave et al. 2005 without height) consistently performed best among the pantropical models tested (R2 = 0.89) and predicted AGB accurately across all size classes-which but for this could not be known without destructive or TLS-derived validation data. Our methods also demonstrate that tree height is difficult to measure in situ, and the inclusion of height in allometric models consistently worsened AGB estimates. We determined that TLS-derived AGB estimates were unbiased. Our approach advances methods to be able to develop, test, and choose allometric models without the need to harvest trees. KW - 3D tree modelling KW - Aboveground biomass estimation KW - Destructive sampling KW - Guyana KW - LiDAR KW - Local tree allometry KW - Model evaluation KW - Quantitative structural model U2 - 10.3390/f10060527 DO - 10.3390/f10060527 M3 - Article VL - 10 JO - Forests: Open Access Journal JF - Forests: Open Access Journal SN - 1999-4907 IS - 6 M1 - 527 ER - TY - JOUR T1 - Tree Root System Characterization and Volume Estimation by Terrestrial Laser Scanning and Quantitative Structure Modeling AU - Smith, Aaron AU - Astrup, Rasmus AU - Raumonen, Pasi AU - Liski, Jari AU - Krooks, Anssi AU - Kaasalainen, Sanna AU - Åkerblom, Markku AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-17

Publisher name: MDPI AG PY - 2014 Y1 - 2014 U2 - 10.3390/f5123274 DO - 10.3390/f5123274 M3 - Article VL - 5 SP - 3274 EP - 3294 JO - Forests: Open Access Journal JF - Forests: Open Access Journal SN - 1999-4907 ER - TY - JOUR T1 - Tumbling asteroids AU - Pravec, P. AU - Harris, A.W. AU - Scheirich, P. AU - Kunirak, P. AU - Sarounova, L. AU - Hergenrother, C.W. AU - Mottola, S. AU - Hicks, M.D. AU - Masi, G. AU - Kruglyh, Yu.N. AU - Shevchenkoh, V.G. AU - Nolan, M.C. AU - Howell, E.S. AU - Kaasalainen, M. AU - Galad, A. AU - Brown, P. AU - DeGraff, D.R. AU - Lambert, J.V. AU - Cooney, W.R. AU - Foglia, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2005 Y1 - 2005 U2 - 10.1016/j.icarus.2004.07.021 DO - 10.1016/j.icarus.2004.07.021 M3 - Article VL - 173 SP - 108 EP - 131 JO - Icarus JF - Icarus SN - 0019-1035 IS - 1 ER - TY - JOUR T1 - Two-Sided Hypergenic Functions AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki AU - Vieira, Nelson PY - 2017 Y1 - 2017 N2 - In this paper we present an analogous of the class of two-sided axial monogenic functions to the case of axial κ-hypermonogenic functions. In order to do that we will solve a Vekua-type system in terms of Bessel functions. AB - In this paper we present an analogous of the class of two-sided axial monogenic functions to the case of axial κ-hypermonogenic functions. In order to do that we will solve a Vekua-type system in terms of Bessel functions. KW - $${\kappa}$$κ-Hypergenic functions KW - Clifford algebras KW - Hypergenic functions KW - Two-side hypergenic functions UR - http://www.scopus.com/inward/record.url?scp=84941331725&partnerID=8YFLogxK U2 - 10.1007/s00006-015-0605-2 DO - 10.1007/s00006-015-0605-2 M3 - Article VL - 27 SP - 111 EP - 123 JO - Advances in Applied Clifford Algebras JF - Advances in Applied Clifford Algebras SN - 0188-7009 IS - 1 ER - TY - JOUR T1 - Uncertainty in multispectral lidar signals caused by incidence angle effects AU - Kaasalainen, Sanna AU - Åkerblom, Markku AU - Nevalainen, Olli AU - Hakala, Teemu AU - Kaasalainen, Mikko PY - 2018/4/6 Y1 - 2018/4/6 N2 - Multispectral terrestrial laser scanning (TLS) is an emerging technology. Several manufacturers already offer commercial dual or three wavelength airborne laser scanners, while multispectral TLS is still carried out mainly with research instruments. Many of these research efforts have focused on the study of vegetation. The aim of this paper is to study the uncertainty of the measurement of spectral indices of vegetation with multispectral lidar. Using two spectral indices as examples, we find that the uncertainty is due to systematic errors caused by the wavelength dependency of laser incidence angle effects. This finding is empirical, and the error cannot be removed by modelling or instrument modification. The discovery and study of these effects has been enabled by hyperspectral and multispectral TLS, and it has become a subject of active research within the past few years. We summarize the most recent studies on multi-wavelength incidence angle effects and present new results on the effect of specular reflection from the leaf surface, and the surface structure, which have been suggested to play a key role. We also discuss the consequences to the measurement of spectral indices with multispectral TLS, and a possible correction scheme using a synthetic laser footprint. AB - Multispectral terrestrial laser scanning (TLS) is an emerging technology. Several manufacturers already offer commercial dual or three wavelength airborne laser scanners, while multispectral TLS is still carried out mainly with research instruments. Many of these research efforts have focused on the study of vegetation. The aim of this paper is to study the uncertainty of the measurement of spectral indices of vegetation with multispectral lidar. Using two spectral indices as examples, we find that the uncertainty is due to systematic errors caused by the wavelength dependency of laser incidence angle effects. This finding is empirical, and the error cannot be removed by modelling or instrument modification. The discovery and study of these effects has been enabled by hyperspectral and multispectral TLS, and it has become a subject of active research within the past few years. We summarize the most recent studies on multi-wavelength incidence angle effects and present new results on the effect of specular reflection from the leaf surface, and the surface structure, which have been suggested to play a key role. We also discuss the consequences to the measurement of spectral indices with multispectral TLS, and a possible correction scheme using a synthetic laser footprint. KW - Hyperspectral KW - Incidence angle KW - Laser scanning KW - Vegetation U2 - 10.1098/rsfs.2017.0033 DO - 10.1098/rsfs.2017.0033 M3 - Article VL - 8 JO - Interface Focus JF - Interface Focus SN - 2042-8898 IS - 2 M1 - 20170033 ER - TY - JOUR T1 - Unimodality and log-concavity of f-vectors for cyclic and ordinary polytopes AU - Major, Laszlo N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: Elsevier PY - 2013 Y1 - 2013 U2 - 10.1016/j.dam.2013.01.008 DO - 10.1016/j.dam.2013.01.008 M3 - Article VL - 161 SP - 1669 EP - 1672 JO - Discrete Applied Mathematics JF - Discrete Applied Mathematics SN - 0166-218X IS - 10-11 ER - TY - JOUR T1 - Using GUHA Data Mining Method in Analyzing Road Traffic Accidents Occurred in the Years 2004–2008 in Finland AU - Turunen, Esko PY - 2017/11/27 Y1 - 2017/11/27 N2 - The suitability of the GUHA data mining method in analyzing a big data matrix is studied in this report in general, and, in particular, a data matrix containing more than 80,000 road traffic accidents occurred in Finland in 2004–2008 is examined by LISp-Miner, a software implementation of GUHA. The general principles of GUHA are first outlined, and then, the road accident data is analyzed. As a result, more than 10,000 associations and dependencies, called hypothesis in the GUHA language, were found; some easily understandable of them are presented here. Our conclusion is that the GUHA method is useful, in particular when one wants to explore relatively small size, but still significant dependencies in a given large data matrix. AB - The suitability of the GUHA data mining method in analyzing a big data matrix is studied in this report in general, and, in particular, a data matrix containing more than 80,000 road traffic accidents occurred in Finland in 2004–2008 is examined by LISp-Miner, a software implementation of GUHA. The general principles of GUHA are first outlined, and then, the road accident data is analyzed. As a result, more than 10,000 associations and dependencies, called hypothesis in the GUHA language, were found; some easily understandable of them are presented here. Our conclusion is that the GUHA method is useful, in particular when one wants to explore relatively small size, but still significant dependencies in a given large data matrix. U2 - 10.1007/s41019-017-0044-2 DO - 10.1007/s41019-017-0044-2 M3 - Article VL - 2 SP - 224 EP - 231 JO - Data Science and Engineering JF - Data Science and Engineering SN - 2364-1185 IS - 3 ER - TY - JOUR T1 - Using video games to combine learning and assessment in mathematics education AU - Kiili, Kristian AU - Devlin, Keith AU - Perttula, Arttu AU - Tuomi, Sanna AU - Lindstedt, Antero PY - 2015 Y1 - 2015 UR - http://journal.seriousgamessociety.org/index.php?journal=IJSG&page=announcement&op=view&path%5B%5D=5 U2 - 10.17083/ijsg.v2i4.98 DO - 10.17083/ijsg.v2i4.98 M3 - Article VL - 2 JO - International Journal of Serious Games JF - International Journal of Serious Games SN - 2384-8766 IS - 4 ER - TY - JOUR T1 - UWB Positioning with Generalized Gaussian Mixture Filters AU - Muller, Philipp AU - Wymeersch, Henk AU - Piche, Robert N1 - Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2014-08-30

Publisher name: Institute of Electrical and Electronics Engineers PY - 2014/10 Y1 - 2014/10 N2 - Low-complexity Bayesian filtering for nonlinear models is challenging. Approximative methods based on Gaussian mixtures (GM) and particle filters are able to capture multimodality, but suffer from high computational demand. In this paper, we provide an in-depth analysis of a generalized GM (GGM), which allows component weights to be negative, and requires significantly fewer components than the traditional GM for ranging models. Based on simulations and tests with real data from a network of UWB nodes, we show how the algorithm’s accuracy depends on the uncertainty of the measurements. For nonlinear ranging the GGM filter outperforms the extended Kalman filter (EKF) in both positioning accuracy and consistency in environments with uncertain measurements, and requires only slightly higher computational effort when the number of measurement channels is small. In networks with highly reliable measurements, the GGM filter yields similar accuracy and better consistency than the EKF. AB - Low-complexity Bayesian filtering for nonlinear models is challenging. Approximative methods based on Gaussian mixtures (GM) and particle filters are able to capture multimodality, but suffer from high computational demand. In this paper, we provide an in-depth analysis of a generalized GM (GGM), which allows component weights to be negative, and requires significantly fewer components than the traditional GM for ranging models. Based on simulations and tests with real data from a network of UWB nodes, we show how the algorithm’s accuracy depends on the uncertainty of the measurements. For nonlinear ranging the GGM filter outperforms the extended Kalman filter (EKF) in both positioning accuracy and consistency in environments with uncertain measurements, and requires only slightly higher computational effort when the number of measurement channels is small. In networks with highly reliable measurements, the GGM filter yields similar accuracy and better consistency than the EKF. KW - Bayesian filtering KW - Gaussian Mixture KW - indoor positioning KW - UWB U2 - 10.1109/TMC.2014.2307301 DO - 10.1109/TMC.2014.2307301 M3 - Article VL - 13 SP - 2406 EP - 2414 JO - IEEE Transactions on Mobile Computing JF - IEEE Transactions on Mobile Computing SN - 1536-1233 IS - 10 ER - TY - JOUR T1 - VLT/SPHERE- and ALMA-based shape reconstruction of asteroid (3) Juno AU - Viikinkoski, M. AU - Kaasalainen, M. AU - Durech, J. AU - Carry, B. AU - Marsset, M. AU - Fusco, T. AU - Dumas, C. AU - Merline, W. J. AU - Yang, B. AU - Berthier, J. AU - Kervella, P. AU - Vernazza, P. PY - 2015/9/1 Y1 - 2015/9/1 N2 - We use the recently released Atacama Large Millimeter Array (ALMA) and VLT/SPHERE science verification data, together with earlier adaptive-optics images, stellar occultation, and lightcurve data to model the 3D shape and spin of the large asteroid (3) Juno with the all-data asteroid modelling (ADAM) procedure. These data set limits on the plausible range of shape models, yielding reconstructions suggesting that, despite its large size, Juno has sizable unrounded features moulded by non-gravitational processes such as impacts. AB - We use the recently released Atacama Large Millimeter Array (ALMA) and VLT/SPHERE science verification data, together with earlier adaptive-optics images, stellar occultation, and lightcurve data to model the 3D shape and spin of the large asteroid (3) Juno with the all-data asteroid modelling (ADAM) procedure. These data set limits on the plausible range of shape models, yielding reconstructions suggesting that, despite its large size, Juno has sizable unrounded features moulded by non-gravitational processes such as impacts. KW - Instrumentation: adaptive optics KW - Instrumentation: interferometers KW - Methods: numerical KW - Minor planets, asteroids: individual: (3) Juno UR - http://www.scopus.com/inward/record.url?scp=84941207014&partnerID=8YFLogxK U2 - 10.1051/0004-6361/201526626 DO - 10.1051/0004-6361/201526626 M3 - Article VL - 581 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - L3 ER - TY - JOUR T1 - Volumes and bulk densities of forty asteroids from ADAM shape modeling AU - Hanuš, J. AU - Viikinkoski, M. AU - Marchis, F. AU - Durech, J. AU - Kaasalainen, M. AU - Delbo, M. AU - Herald, D. AU - Frappa, E. AU - Hayamizu, T. AU - Kerr, S. AU - Preston, S. AU - Timerson, B. AU - Dunham, D. AU - Talbot, J. PY - 2017/5/1 Y1 - 2017/5/1 N2 - Context. Disk-integrated photometric data of asteroids do not contain accurate information on shape details or size scale. Additional data such as disk-resolved images or stellar occultation measurements further constrain asteroid shapes and allow size estimates. Aims. We aim to use all the available disk-resolved images of approximately forty asteroids obtained by the Near-InfraRed Camera (Nirc2) mounted on the W.M. Keck II telescope together with the disk-integrated photometry and stellar occultation measurements to determine their volumes. We can then use the volume, in combination with the known mass, to derive the bulk density. Methods. We downloaded and processed all the asteroid disk-resolved images obtained by the Nirc2 that are available in the Keck Observatory Archive (KOA). We combined optical disk-integrated data and stellar occultation profiles with the disk-resolved images and use the All-Data Asteroid Modeling (ADAM) algorithm for the shape and size modeling. Our approach provides constraints on the expected uncertainty in the volume and size as well. Results. We present shape models and volume for 41 asteroids. For 35 of these asteroids, the knowledge of their mass estimates from the literature allowed us to derive their bulk densities. We see a clear trend of lower bulk densities for primitive objects (C-complex) and higher bulk densities for S-complex asteroids. The range of densities in the X-complex is large, suggesting various compositions. We also identified a few objects with rather peculiar bulk densities, which is likely a hint of their poor mass estimates. Asteroid masses determined from the Gaia astrometric observations should further refine most of the density estimates. AB - Context. Disk-integrated photometric data of asteroids do not contain accurate information on shape details or size scale. Additional data such as disk-resolved images or stellar occultation measurements further constrain asteroid shapes and allow size estimates. Aims. We aim to use all the available disk-resolved images of approximately forty asteroids obtained by the Near-InfraRed Camera (Nirc2) mounted on the W.M. Keck II telescope together with the disk-integrated photometry and stellar occultation measurements to determine their volumes. We can then use the volume, in combination with the known mass, to derive the bulk density. Methods. We downloaded and processed all the asteroid disk-resolved images obtained by the Nirc2 that are available in the Keck Observatory Archive (KOA). We combined optical disk-integrated data and stellar occultation profiles with the disk-resolved images and use the All-Data Asteroid Modeling (ADAM) algorithm for the shape and size modeling. Our approach provides constraints on the expected uncertainty in the volume and size as well. Results. We present shape models and volume for 41 asteroids. For 35 of these asteroids, the knowledge of their mass estimates from the literature allowed us to derive their bulk densities. We see a clear trend of lower bulk densities for primitive objects (C-complex) and higher bulk densities for S-complex asteroids. The range of densities in the X-complex is large, suggesting various compositions. We also identified a few objects with rather peculiar bulk densities, which is likely a hint of their poor mass estimates. Asteroid masses determined from the Gaia astrometric observations should further refine most of the density estimates. KW - Methods: Numerical KW - Methods: Observational KW - Minor planets, asteroids: General KW - Techniques: Photometric U2 - 10.1051/0004-6361/201629956 DO - 10.1051/0004-6361/201629956 M3 - Article VL - 601 JO - Astronomy and Astrophysics JF - Astronomy and Astrophysics SN - 0004-6361 M1 - A114 ER - TY - JOUR T1 - Yksilöllinen opetus ja itsearviointi osana yliopistomatematiikan opintojakson suoritusta AU - Erämaa, Juha AU - Kaarakka, Terhi AU - Elomaa, Tapio PY - 2020/4/30 Y1 - 2020/4/30 N2 - Eriyttämisen tarve ja sähköisten oppimisympäristöjen antama tuki ovat suunnanneet yliopistojen opintojaksojen käytännön järjestelyjä kohti sulautuvaa oppimista ja opetusta. Toisaalta työelämä tarvitsee oppimiskykyisiä ammattilaisia erilaisiin toimiin. Itse arviointi on yksi oppimiskykyä vahvistava työelämätaito. Teimme Tampereen teknillisellä yliopistolla opetuskokeilun, jossa edellä mainitut asiat yhdistettiin. Opiskelijat tekivät itsenäisesti sähköisestä materiaalista muodostetun oppimiskokonaisuuden, jossa eritasoisilla monipuolisilla sähköisillä tehtävillä ja itsearvioinnilla pyrittiin syvällisempään oppimiseen. Artikkelissa on kuvattu tutkimusta ja siitä saatuja alustavia positiivisia tuloksia. Tutkimukseen osallistui 62 opiskelijaa kurssiin 163:sta osallistujasta. Tutkimusaineiston kysymykset olivat osana oppimiskokonaisuuden tehtäviä. AB - Eriyttämisen tarve ja sähköisten oppimisympäristöjen antama tuki ovat suunnanneet yliopistojen opintojaksojen käytännön järjestelyjä kohti sulautuvaa oppimista ja opetusta. Toisaalta työelämä tarvitsee oppimiskykyisiä ammattilaisia erilaisiin toimiin. Itse arviointi on yksi oppimiskykyä vahvistava työelämätaito. Teimme Tampereen teknillisellä yliopistolla opetuskokeilun, jossa edellä mainitut asiat yhdistettiin. Opiskelijat tekivät itsenäisesti sähköisestä materiaalista muodostetun oppimiskokonaisuuden, jossa eritasoisilla monipuolisilla sähköisillä tehtävillä ja itsearvioinnilla pyrittiin syvällisempään oppimiseen. Artikkelissa on kuvattu tutkimusta ja siitä saatuja alustavia positiivisia tuloksia. Tutkimukseen osallistui 62 opiskelijaa kurssiin 163:sta osallistujasta. Tutkimusaineiston kysymykset olivat osana oppimiskokonaisuuden tehtäviä. M3 - Article VL - 3 SP - 44 EP - 58 JO - FMSERA Journal JF - FMSERA Journal SN - 2490-1583 IS - 1 ER - TY - JOUR T1 - Yliopistomatematiikan sähköisten tehtävien ja matemaattisen ajattelun kehittäminen AU - Myllykoski, Tuomas Jaakko AU - Mattila, Pekka AU - Ali-Löytty, Simo AU - Kaarakka, Terhi AU - Viro, Elina PY - 2018 Y1 - 2018 N2 - Matemaattisten tehtävien ratkaisujen kirjoittaminen digitaaliseen muotoon yleistyy koko ajan ylioppilaskirjoitusten, sähköisen tenttimisen ja avointen verkkokurssien takia. Samalla tarve ratkaisujen automaattiseen arviointiin kasvaa. Vaikka monet peruskurssitason harjoitustehtävät tarkistetaan jo nyt sähköisesti, olisi hyödyllistä voida tarkistaa opiskelijan koko päättelyketju pelkän vastauksen sijaan. Tässä julkaisussa saadaan luokiteltua, millaisia virheitä opiskelijat tekevät yhdessä tehtävässä ja pohditaan, kuinka tätä voidaan hyödyntää opiskelijoille annettavassa, automatisoidussa palautteessa siten, että palautteella ohjataan opiskelijan matemaattisen ajattelun kehittymistä. Lisäksi TTY:llä on pitkään testattu ensimmäisen vuoden opiskelijoiden matemaattisia perustaitoja, joten osaamme kohdentaa tukitoimet keskeisiin ongelma-alueisiin, kuten trigonometriaan. AB - Matemaattisten tehtävien ratkaisujen kirjoittaminen digitaaliseen muotoon yleistyy koko ajan ylioppilaskirjoitusten, sähköisen tenttimisen ja avointen verkkokurssien takia. Samalla tarve ratkaisujen automaattiseen arviointiin kasvaa. Vaikka monet peruskurssitason harjoitustehtävät tarkistetaan jo nyt sähköisesti, olisi hyödyllistä voida tarkistaa opiskelijan koko päättelyketju pelkän vastauksen sijaan. Tässä julkaisussa saadaan luokiteltua, millaisia virheitä opiskelijat tekevät yhdessä tehtävässä ja pohditaan, kuinka tätä voidaan hyödyntää opiskelijoille annettavassa, automatisoidussa palautteessa siten, että palautteella ohjataan opiskelijan matemaattisen ajattelun kehittymistä. Lisäksi TTY:llä on pitkään testattu ensimmäisen vuoden opiskelijoiden matemaattisia perustaitoja, joten osaamme kohdentaa tukitoimet keskeisiin ongelma-alueisiin, kuten trigonometriaan. M3 - Article VL - 2 SP - 46 EP - 56 JO - FMSERA Journal JF - FMSERA Journal SN - 2489-4583 IS - 1 ER - TY - JOUR T1 - Bagdad - matematiikkaa täältä ikuisuuteen matematiikkanäyttely AU - Eriksson, Sirkka-Liisa AU - Vainio, Johanna N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2015-01-14 PY - 2014 Y1 - 2014 M3 - Article VL - 2 SP - 17 EP - 46 JO - Lumat JF - Lumat SN - 2323-7112 IS - 1 ER - TY - JOUR T1 - Projekteja yläkoulun matematiikkaan AU - Eriksson, Sirkka-Liisa AU - Salminen, Juho AU - Viro, Elina PY - 2016/2/15 Y1 - 2016/2/15 M3 - Article JO - LUMA-sanomat JF - LUMA-sanomat SN - 1799-3385 ER - TY - JOUR T1 - Projektioppiminen T2 - lähtökohtana ympäröivä maailma AU - Eriksson, Sirkka-Liisa AU - Viro, Elina PY - 2015/3/11 Y1 - 2015/3/11 N2 - Oppilaat tarvitsevat matematiikkaa arjessa ja tulevassa työelämässä, ei vain matematiikan tunneilla. Projektioppiminen-kehittämishankeen tarkoituksena on lisätä yläkouluikäisten oppilaiden motivaatiota matematiikkaa kohtaan ja luoda samalla matematiikkainnostusta. AB - Oppilaat tarvitsevat matematiikkaa arjessa ja tulevassa työelämässä, ei vain matematiikan tunneilla. Projektioppiminen-kehittämishankeen tarkoituksena on lisätä yläkouluikäisten oppilaiden motivaatiota matematiikkaa kohtaan ja luoda samalla matematiikkainnostusta. KW - Projektioppiminen KW - matematiikan opetus M3 - Article JO - LUMA-sanomat JF - LUMA-sanomat SN - 1799-3385 ER - TY - JOUR T1 - Projektioppiminen yläkoulun matematiikassa AU - Viro, Elina AU - Eriksson, Sirkka-Liisa PY - 2015 Y1 - 2015 UR - http://luma.fi/lumat/4273 M3 - Article VL - 3 SP - 1005 EP - 1009 JO - Lumat JF - Lumat SN - 2323-7112 IS - 7 ER - TY - JOUR T1 - Projektipankki yläkoulun matematiikkaan AU - Viro, Elina PY - 2016/10/26 Y1 - 2016/10/26 M3 - Article VL - 2016 SP - 29 EP - 30 JO - Dimensio JF - Dimensio SN - 0782-6648 IS - 5 ER - TY - JOUR T1 - Sähkömagneettinen malli funktoreina ja luonnollisina muunnoksina AU - Kovanen, Tuomas AU - Tarhasaari, Timo AU - Kettunen, Lauri PY - 2016 Y1 - 2016 M3 - Article SP - 21 EP - 30 JO - Arkhimedes JF - Arkhimedes SN - 0004-1920 ER - TY - JOUR T1 - Simulointi nopeuttaa käyttöiän määritystä AU - Ojala, Petteri AU - Saarenrinne, Pentti AU - Miettinen, Juha AU - Multanen, Petteri AU - Kiilunen, Janne AU - Hietala, Jukka-Pekka AU - Kolu, Antti AU - Pippola, Juha AU - Mostofizadeh, Milad AU - Ylönen, Markku N1 - ORG=mol,0.25 ORG=mei,0.25 ORG=iha,0.25 ORG=dee,0.25 PY - 2015 Y1 - 2015 M3 - Article VL - 2 SP - 24 EP - 27 JO - Promaint JF - Promaint SN - 1797-2000 ER - TY - JOUR T1 - Taivaalliset projektiot: terapiaa imversio-ongelmaisille AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-17

Publisher name: Suomen Fyysikkoseura PY - 2014 Y1 - 2014 M3 - Article SP - 25 EP - 31 JO - Arkhimedes JF - Arkhimedes SN - 0004-1920 IS - 4 ER - TY - JOUR T1 - Tampereen matemaattisten aineiden aineenopettajakoulutus AU - Eriksson, Sirkka-Liisa AU - Haukkanen, Pentti AU - Hukka, Terttu I. AU - Lemmetyinen, Helge N1 - ORG=mat,0.7 ORG=keb,0.3 PY - 2015/3/11 Y1 - 2015/3/11 N2 - Esittelemme tässä artikkelissa yleisesti Tampereen yliopistojen aineenopettajakoulutusta. Aineenopettajakoulutuksessa on Tampereen yliopiston ja Tampereen teknillisen yliopiston välillä paljon yhteistä toimintaa. Kerromme Tampereen aineenopettajakoulutuksen taustasta. Tämän jälkeen kuvaamme opetuksen tärkeimpiä piirteitä kummastakin yliopistosta erikseen ja sen jälkeen kokoamme esityksen yhteisesti toteutettavasta osioista. Lopuksi esittelemme opetukseen liittyvää kehitystoimintaa ja tutkimusta. AB - Esittelemme tässä artikkelissa yleisesti Tampereen yliopistojen aineenopettajakoulutusta. Aineenopettajakoulutuksessa on Tampereen yliopiston ja Tampereen teknillisen yliopiston välillä paljon yhteistä toimintaa. Kerromme Tampereen aineenopettajakoulutuksen taustasta. Tämän jälkeen kuvaamme opetuksen tärkeimpiä piirteitä kummastakin yliopistosta erikseen ja sen jälkeen kokoamme esityksen yhteisesti toteutettavasta osioista. Lopuksi esittelemme opetukseen liittyvää kehitystoimintaa ja tutkimusta. M3 - Article VL - 3 SP - 800 EP - 807 JO - Lumat JF - Lumat SN - 2323-7112 IS - 6 ER - TY - JOUR T1 - Uusi koulukohtainen syventävä kurssi ja oppikirja lukioihin AU - Eriksson, Sirkka-Liisa AU - Kaarakka, Terhi N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Article VL - 1 SP - 29 EP - 30 JO - Solmu Matematiikkalehti JF - Solmu Matematiikkalehti SN - 1458-8048 ER - TY - JOUR T1 - Maaliskuun puheenaihe: Mielenkiintoista matematiikkaa opetukseen LUMA-sanomat AU - Eriksson, Sirkka-Liisa N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Article SP - 1 EP - 3 JO - LUMA-sanomat JF - LUMA-sanomat SN - 1799-3385 IS - Maaliskuu ER - TY - JOUR T1 - On the arity gap of finite functions T2 - Results and applications AU - Couceiro, Miguel AU - Lehtonen, Erkko PY - 2016 Y1 - 2016 N2 - Let A be a finite set and B an arbitrary set with at least two elements. The arity gap of a function f : An → B is the minimum decrease in the number of essential variables when essential variables of f are identified. A non- Trivial fact is that the arity gap of such B-valued functions on A is at most |A|. Even less trivial to verify is the fact that the arity gap of B-valued functions on A with more than |A| essential variables is at most 2. These facts ask for a classification of B-valued functions on A in terms of their arity gap. In this paper, we survey what is known about this problem. We present a general characterization of the arity gap of B-valued functions on A and provide explicit classifications of the arity gap of Boolean and pseudo-Boolean functions. Moreover, we reveal unsettled questions related to this topic, and discuss links and possible applications of some results to other subjects of research. AB - Let A be a finite set and B an arbitrary set with at least two elements. The arity gap of a function f : An → B is the minimum decrease in the number of essential variables when essential variables of f are identified. A non- Trivial fact is that the arity gap of such B-valued functions on A is at most |A|. Even less trivial to verify is the fact that the arity gap of B-valued functions on A with more than |A| essential variables is at most 2. These facts ask for a classification of B-valued functions on A in terms of their arity gap. In this paper, we survey what is known about this problem. We present a general characterization of the arity gap of B-valued functions on A and provide explicit classifications of the arity gap of Boolean and pseudo-Boolean functions. Moreover, we reveal unsettled questions related to this topic, and discuss links and possible applications of some results to other subjects of research. UR - http://www.scopus.com/inward/record.url?scp=84979953947&partnerID=8YFLogxK M3 - Review Article VL - 27 SP - 193 EP - 207 JO - Journal of Multiple-Valued Logic and Soft Computing JF - Journal of Multiple-Valued Logic and Soft Computing SN - 1542-3980 IS - 2-3 ER - TY - JOUR T1 - Neighbour species richness and local structural variability modulate aboveground allocation patterns and crown morphology of individual trees AU - Kunz, Matthias AU - Fichtner, Andreas AU - Härdtle, Werner AU - Raumonen, Pasi AU - Bruelheide, Helge AU - von Oheimb, Goddert PY - 2019 Y1 - 2019 N2 - Local neighbourhood interactions are considered a main driver for biodiversity–productivity relationships in forests. Yet, the structural responses of individual trees in species mixtures and their relation to crown complementarity remain poorly understood. Using a large-scale forest experiment, we studied the impact of local tree species richness and structural variability on above-ground wood volume allocation patterns and crown morphology. We applied terrestrial laser scanning to capture the three-dimensional structure of trees and their temporal dynamics. We found that crown complementarity and crown plasticity increased with species richness. Trees growing in species-rich neighbourhoods showed enhanced aboveground wood volume both in trunks and branches. Over time, neighbourhood diversity induced shifts in wood volume allocation in favour of branches, in particular for morphologically flexible species. Our results demonstrate that diversity-mediated shifts in allocation pattern and crown morphology are a fundamental mechanism for crown complementarity and may be an important driver of overyielding. AB - Local neighbourhood interactions are considered a main driver for biodiversity–productivity relationships in forests. Yet, the structural responses of individual trees in species mixtures and their relation to crown complementarity remain poorly understood. Using a large-scale forest experiment, we studied the impact of local tree species richness and structural variability on above-ground wood volume allocation patterns and crown morphology. We applied terrestrial laser scanning to capture the three-dimensional structure of trees and their temporal dynamics. We found that crown complementarity and crown plasticity increased with species richness. Trees growing in species-rich neighbourhoods showed enhanced aboveground wood volume both in trunks and branches. Over time, neighbourhood diversity induced shifts in wood volume allocation in favour of branches, in particular for morphologically flexible species. Our results demonstrate that diversity-mediated shifts in allocation pattern and crown morphology are a fundamental mechanism for crown complementarity and may be an important driver of overyielding. KW - BEF-China KW - biodiversity KW - crown complementarity KW - ecosystem functioning KW - forests KW - productivity KW - terrestrial laser scanning U2 - 10.1111/ele.13400 DO - 10.1111/ele.13400 M3 - Letter VL - 22 SP - 2130 EP - 2140 JO - ECOLOGY LETTERS JF - ECOLOGY LETTERS SN - 1461-023X IS - 12 ER - TY - JOUR T1 - Application and theory of Petri nets and other models of concurrency T2 - Special issue of selected papers from Petri Nets 2015 AU - Devillers, Raymond AU - Valmari, Antti AU - Penczek, Wojciech PY - 2016/9/13 Y1 - 2016/9/13 U2 - 10.3233/FI-2016-1373 DO - 10.3233/FI-2016-1373 M3 - Editorial VL - 146 SP - v-vi JO - Fundamenta Informaticae JF - Fundamenta Informaticae SN - 0169-2968 IS - 1 ER - TY - JOUR T1 - Editorial: is Game-Based Math Learning Finally Coming of Age? AU - Kiili, Kristian AU - Devlin, Keith AU - Multisilta, Jari PY - 2015/12/8 Y1 - 2015/12/8 M3 - Editorial VL - 2 JO - International Journal of Serious Games JF - International Journal of Serious Games SN - 2384-8766 IS - 4 M1 - 1 ER - TY - CHAP T1 - Abstractions for transition systems with applications to stubborn sets AU - Hansen, Henri PY - 2017/1/1 Y1 - 2017/1/1 N2 - Partial order reduction covers a range of techniques based on eliminating unnecessary transitions when generating a state space. On the other hand, abstractions replace sets of states of a system with abstract representatives in order to create a smaller state space. This article explores how stubborn sets and abstraction can be combined. We provide examples to provide intuition and expand on some recent results. We provide a classification of abstractions and give some novel results on what is needed to combine abstraction and partial order reduction in a sound way. AB - Partial order reduction covers a range of techniques based on eliminating unnecessary transitions when generating a state space. On the other hand, abstractions replace sets of states of a system with abstract representatives in order to create a smaller state space. This article explores how stubborn sets and abstraction can be combined. We provide examples to provide intuition and expand on some recent results. We provide a classification of abstractions and give some novel results on what is needed to combine abstraction and partial order reduction in a sound way. U2 - 10.1007/978-3-319-51046-0_6 DO - 10.1007/978-3-319-51046-0_6 M3 - Chapter SN - 978-3-319-51045-3 T3 - Lecture Notes in Computer Science SP - 104 EP - 123 BT - Concurrency, Security, and Puzzles A2 - Gibson-Robinson, Thomas A2 - Hopcroft, Philippa A2 - Lazić, Ranko PB - Springer International Publishing ER - TY - CHAP T1 - Akustinen mallinnus AU - Pohjolainen, Seppo AU - Suutala, Antti N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Chapter SN - 978-951-0-35408-7 SP - 238 EP - 259 BT - Matemaattinen mallinnus A2 - Pohjolainen, Seppo PB - WSOYpro CY - Helsinki ER - TY - CHAP T1 - Datapohjaiset mallit AU - Merikoski, Jorma AU - Turunen, Esko AU - Raivio, Kimmo AU - Mantere, Timo N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Chapter SN - 978-951-0-35408-7 SP - 77 EP - 146 BT - Matemaattinen mallinnus A2 - Pohjolainen, Seppo PB - WSOYpro CY - Helsinki ER - TY - CHAP T1 - Kokonaislukumallit AU - Silvennoinen, Risto N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Chapter SN - 978-951-0-35408-7 SP - 52 EP - 76 BT - Matemaattinen mallinnus A2 - Pohjolainen, Seppo PB - WSOYpro CY - Helsinki ER - TY - CHAP T1 - Laskenta ja visualisointi AU - Piche, Robert N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Chapter SN - 978-951-0-35408-7 SP - 211 EP - 222 BT - Matemaattinen mallinnus A2 - Pohjolainen, Seppo PB - WSOYpro CY - Helsinki ER - TY - CHAP T1 - Mathematics Education in EU for STEM Disciplines AU - Pohjolainen, Seppo PY - 2018 Y1 - 2018 U2 - 10.1007/978-3-319-71416-5_1 DO - 10.1007/978-3-319-71416-5_1 M3 - Chapter SN - 978-3-319-71415-8 SP - 1 EP - 6 BT - Modern Mathematics Education for Engineering Curricula in Europe A2 - Pohjolainen, Seppo A2 - Myllykoski, Tuomas A2 - Mercat, Christian A2 - Sosnovsky, Sergey PB - Birkhäuser ER - TY - CHAP T1 - Mobile Tracking in Mixed Line-ofsight/Non-line-of-sight Conditions: Algorithms and Theoretical Lower Bound. Chapter 21 AU - Liang, Chen AU - Ali-Löytty, Simo AU - Piche, Robert AU - Lenan, Wu N1 - ei ut-numeroa 5.4.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Chapter SN - 978-0-470-94342-7 SP - 685 EP - 708 BT - Handbook of Position Location: Theory, Practice and Advances A2 - Zekavat, Reza A2 - Buehrer, R. Michael PB - WILEY-IEEE PRESS CY - Hoboken, NJ ER - TY - CHAP T1 - More stubborn set methods for process algebras AU - Valmari, Antti PY - 2017/1/1 Y1 - 2017/1/1 N2 - Six stubborn set methods for computing reduced labelled transition systems are presented. Two of them preserve the traces, and one is tailored for on-the-fly verification of safety properties. The rest preserve the tree failures, fair testing equivalence, or the divergence traces. Two methods are entirely new, the ideas of three are recent and the adaptation to the process-algebraic setting with non-deterministic actions is new, and one is recent but slightly generalized. Most of the methods address problems in earlier solutions to the so-called ignoring problem. The correctness of each method is proven, and efficient implementation is discussed. AB - Six stubborn set methods for computing reduced labelled transition systems are presented. Two of them preserve the traces, and one is tailored for on-the-fly verification of safety properties. The rest preserve the tree failures, fair testing equivalence, or the divergence traces. Two methods are entirely new, the ideas of three are recent and the adaptation to the process-algebraic setting with non-deterministic actions is new, and one is recent but slightly generalized. Most of the methods address problems in earlier solutions to the so-called ignoring problem. The correctness of each method is proven, and efficient implementation is discussed. UR - http://www.scopus.com/inward/record.url?scp=85006810860&partnerID=8YFLogxK U2 - 10.1007/978-3-319-51046-0_13 DO - 10.1007/978-3-319-51046-0_13 M3 - Chapter SN - 978-3-319-51045-3 T3 - Lecture Notes in Computer Science SP - 246 EP - 271 BT - Concurrency, Security, and Puzzles A2 - Gibson-Robinson, Thomas A2 - Hopcroft, Philippa A2 - Lazić, Ranko PB - Springer International Publishing ER - TY - CHAP T1 - Overview of the Results and Recommendations AU - Pohjolainen, Seppo AU - Sosnovsky, Sergey AU - Mercat, Christian PY - 2018 Y1 - 2018 U2 - 10.1007/978-3-319-71416-5_10 DO - 10.1007/978-3-319-71416-5_10 M3 - Chapter SN - 978-3-319-71415-8 SP - 185 EP - 196 BT - Modern Mathematics Education for Engineering Curricula in Europe A2 - Pohjolainen, Seppo A2 - Myllykoski, Tuomas A2 - Mercat, Christian A2 - Sosnovsky, Sergey PB - Birkhäuser CY - Switzerland ER - TY - CHAP T1 - Acoustic Modelling AU - Pohjolainen, Seppo AU - Suutala, Antti N1 - INT=mat,”Suutala, Antti" PY - 2016/6/30 Y1 - 2016/6/30 N2 - Let us examine the behaviour of sound in a gas or in a liquid medium. From a physical point of view, the sound we hear is created by the pressure change in the medium surrounding us that is sensed by our ears. The equations describing the behaviour of a liquid or a gas are based on well-known equations of fluid mechanics. Therefore in acoustics, they are often referred to as fluids. In the following sections we present a simple wave equation, which is the simplest of (linear) equations used to model acoustical phenomena. Even though the wave equation is quite a simplified model, it has proven to be extremely useful for describing the behaviour of sound in the most common fluid we face every day, namely air. AB - Let us examine the behaviour of sound in a gas or in a liquid medium. From a physical point of view, the sound we hear is created by the pressure change in the medium surrounding us that is sensed by our ears. The equations describing the behaviour of a liquid or a gas are based on well-known equations of fluid mechanics. Therefore in acoustics, they are often referred to as fluids. In the following sections we present a simple wave equation, which is the simplest of (linear) equations used to model acoustical phenomena. Even though the wave equation is quite a simplified model, it has proven to be extremely useful for describing the behaviour of sound in the most common fluid we face every day, namely air. U2 - 10.1007/978-3-319-27836-0_11 DO - 10.1007/978-3-319-27836-0_11 M3 - Chapter SN - 978-3-319-27834-6 SP - 185 EP - 205 BT - Mathematical Modelling A2 - Pohjolainen, Seppo PB - Springer CY - Switzerland ER - TY - CHAP T1 - A differential form approach to Dirac operators on surfaces AU - Orelma, Heikki AU - Sommen, Frank N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1007/978-3-0346-0246-4_15 DO - 10.1007/978-3-0346-0246-4_15 M3 - Chapter SN - 978-3-0346-0245-7 SP - 213 EP - 232 BT - Hypercomplex Analysis and Applications. Trends in Mathematics A2 - Sabadini, Irene A2 - Sommen, Frank PB - Birkhäuser CY - Basel ER - TY - CHAP T1 - A hyperbolic interpretation of Cauchy-type kernels in hyperbolic function theory in hypercomplex analysis AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1007/978-3-0346-0246-4_4 DO - 10.1007/978-3-0346-0246-4_4 M3 - Chapter SN - 978-3-0346-0245-7 SP - 43 EP - 59 BT - Hypercomplex Analysis and Applications. Trends in Mathematics A2 - Sabadini, Irene A2 - Sommen, Frank PB - Birkhäuser CY - Basel ER - TY - CHAP T1 - A Lukasiewicz-style Many-Valued Similarity Reasoning T2 - Review AU - Turunen, Esko PY - 2003 Y1 - 2003 M3 - Chapter SN - 3-7908-1541-1 T3 - Studies in Fuzziness and Soft Computing SP - 315 EP - 348 BT - Beyond Two A2 - Fitting, Melvin A2 - Orlowska, Ewa PB - Physica-Verlag CY - Heidelberg ER - TY - CHAP T1 - A Network-Centric Snapshot of Value Co-Creation in Finnish Innovation Financing AU - Huhtamäki, Jukka AU - Russell, Martha G. AU - Still, K. AU - Rubens, Neil N1 - ei ut-numeroa 8.3.2014

Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Chapter SP - 13 EP - 21 BT - The Open Source Business Resource A2 - McPhee, Chris A2 - Seppä, Marko A2 - Tanev, Stoyan PB - Talent First Network ER - TY - CHAP T1 - Asteroid Models from Multiple Data Sources AU - Ďurech, J. AU - Carry, Benoit AU - Delbo, Marco AU - Kaasalainen, Mikko AU - Viikinkoski, Matti PY - 2015 Y1 - 2015 UR - http://www.uapress.arizona.edu/Books/bid2555.htm U2 - 10.2458/azu_uapress_9780816532131-ch010 DO - 10.2458/azu_uapress_9780816532131-ch010 M3 - Chapter SN - 978-0-8165-3213-1 SP - 183 EP - 202 BT - Asteroids IV A2 - Michel, Patrick A2 - DeMeo, Francesca E. A2 - Bottke Jr., William F. PB - UNIVERSITY OF ARIZONA PRESS CY - Tucson ER - TY - CHAP T1 - Considering learners' perspectives to personal learning environments in course design AU - Väljataga, T. AU - Pata, K. AU - Tammets, K. N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Chapter SP - 85 EP - 108 BT - WEB 2.0 Based E-Learning: Applying Social Informatics for Tertiary Teaching A2 - Lee, M.J.W. PB - IGI Global CY - Hershey ER - TY - CHAP T1 - Context Awareness for Semantic Mobile Computing AU - Rivero-Rodriguez, Alejandro AU - Nykänen, Ossi PY - 2017 Y1 - 2017 N2 - In a plethora of smart phones and related mobile applications, users crave innovative and personalized services that adapt to their situation. To achieve that, smart phones need to understand user context and needs for latter providing them with adequate services. This chapter discusses how context can be understood, represented and exploited in smart phones, using techniques from the fields of Semantic Computing, Machine Learning and Graph Theory. AB - In a plethora of smart phones and related mobile applications, users crave innovative and personalized services that adapt to their situation. To achieve that, smart phones need to understand user context and needs for latter providing them with adequate services. This chapter discusses how context can be understood, represented and exploited in smart phones, using techniques from the fields of Semantic Computing, Machine Learning and Graph Theory. U2 - 10.1007/978-3-319-50427-8_12 DO - 10.1007/978-3-319-50427-8_12 M3 - Chapter SN - 978-3-319-50426-1 SP - 251 EP - 267 BT - Multi-Technology Positioning A2 - Nurmi, Jari A2 - Lohan, Elena-Simona A2 - Wymeersch, Henk A2 - Seco-Granados, Gonzalo A2 - Nykänen, Ossi PB - Springer International Publishing CY - Cham ER - TY - CHAP T1 - Estimation of Model Parameters AU - Piche, Robert N1 - Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2013-05-29 PY - 2013 Y1 - 2013 M3 - Chapter SN - 978-1-1182-9441-3 SP - 169 EP - 190 BT - Mathematical Modeling with Multidisciplinary Applications A2 - Yang, Xin-She PB - John Wiley & Sons CY - Hoboken, NJ, USA ER - TY - CHAP T1 - Estimation of the Mechanical Power of a Kite Wind Generator AU - Rautakorpi, Pauli AU - Argatov, Ivan AU - Silvennoinen, Risto N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-07-29 PY - 2013 Y1 - 2013 M3 - Chapter SN - 978-1-922227-10-2 SP - 1 EP - 28 BT - Renewable Energy for Sustainable Future A2 - Lohani, Sunil Prasad PB - ICONCEPT PRESS CY - Hong Kong ER - TY - CHAP T1 - Integer Models AU - Silvennoinen, Risto AU - Merikoski, Jorma PY - 2016 Y1 - 2016 N2 - The examples on “network design” (p. 15), “river and flood models” (p. 20) and “urban water systems” (p. 21) lead us to consider networks. A useful way to describe a network is to define for each pair of nodes a function whose value is 1 if there is a direct connection between these nodes in the network, and 0 otherwise. More generally, x = 1 can be used to indicate that a certain event occurs and x = 0 that it does not. Indeed, binary (i.e., 0-1-valued) variables appear in many models, and so do also other integer-valued variables. In this chapter we shall take a look at such models. AB - The examples on “network design” (p. 15), “river and flood models” (p. 20) and “urban water systems” (p. 21) lead us to consider networks. A useful way to describe a network is to define for each pair of nodes a function whose value is 1 if there is a direct connection between these nodes in the network, and 0 otherwise. More generally, x = 1 can be used to indicate that a certain event occurs and x = 0 that it does not. Indeed, binary (i.e., 0-1-valued) variables appear in many models, and so do also other integer-valued variables. In this chapter we shall take a look at such models. U2 - 10.1007/978-3-319-27836-0_4 DO - 10.1007/978-3-319-27836-0_4 M3 - Chapter SN - 978-3-319-27834-6 SP - 35 EP - 54 BT - Mathematical Modelling A2 - Pohjolainen, Seppo PB - Springer International Publishing ER - TY - CHAP T1 - Integral Formulas for k-hypermonogenic Functions in R3 AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki AU - Nelson, Vieira N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2015-01-14

Publisher name: Springer PY - 2014 Y1 - 2014 U2 - 10.1007/978-3-319-08771-9_8 DO - 10.1007/978-3-319-08771-9_8 M3 - Chapter SN - 978-3-319-08770-2 T3 - Trends in Mathematics SP - 119 EP - 132 BT - Hypercomplex Analysis: New Perspectives and Applications PB - Springer ER - TY - CHAP T1 - Korkeakoulumatematiikka teekkarin kompastuskivenä? AU - Silius, Kirsi AU - Pohjolainen, Seppo AU - Miilumäki, Thumas AU - Kangas, Jussi AU - Joutsenlahti, Jorma N1 - Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Chapter SN - 978-951-44-8610-4 SP - 242 EP - 265 BT - Korkeajännityksiä - kohti osallisuutta luovaa korkeakoulutusta A2 - Mäkinen, Marita A2 - Korhonen, Vesa A2 - Annala, Johanna A2 - Kalli, Pekka A2 - Svärd, Päivi A2 - Värri, Veli-Matti PB - Tampere University Press CY - Tampere ER - TY - CHAP T1 - On Robustness of Strongly Stable Semigroups with Spectrum on iR AU - Paunonen, Lassi PY - 2015 Y1 - 2015 N2 - We study the robustness properties of strong stability of a strongly continuous semigroup on a Hilbert space. We concentrate on a situation where the generator of the unperturbed semigroup has a finite spectral point on the imaginary axis and the resolvent operator is polynomially bounded elsewhere on the imaginary axis. As our main result we present conditions for preservation of the strong stability of the semigroup under bounded perturbations. AB - We study the robustness properties of strong stability of a strongly continuous semigroup on a Hilbert space. We concentrate on a situation where the generator of the unperturbed semigroup has a finite spectral point on the imaginary axis and the resolvent operator is polynomially bounded elsewhere on the imaginary axis. As our main result we present conditions for preservation of the strong stability of the semigroup under bounded perturbations. KW - Strongly Continuous Semigroup KW - Functional Analysis U2 - 10.1007/978-3-319-12145-1 DO - 10.1007/978-3-319-12145-1 M3 - Chapter SN - 978-3-319-12144-4 T3 - Springer Proceedings in Mathematics & Statistics SP - 105 EP - 121 BT - Semigroups of Operators -Theory and Applications A2 - Banasiak, Jacek A2 - Bobrowski, Adam A2 - Lachowicz, Mirosław PB - Springer International Publishing ER - TY - CHAP T1 - Ostinato T2 - The Exploration-Automation Cycle of User-Centric, Process-Automated Data-Driven Visual Network Analytics AU - Huhtamäki, Jukka AU - Russell, Martha G. AU - Rubens, Neil AU - Still, Kaisa PY - 2015 Y1 - 2015 U2 - 10.1007/978-3-319-18552-1 DO - 10.1007/978-3-319-18552-1 M3 - Chapter SN - 978-3-319-18551-4 T3 - Computational Social Science SP - 197 EP - 222 BT - Transparency in Social Media A2 - Matei, Sorin Adam A2 - Russell, Martha G. A2 - Bertino, Elisa PB - Springer International Publishing ER - TY - CHAP T1 - Quaternionic Hyperbolic Function Theory AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - EXT="Eriksson, Sirkka-Liisa" jufoid=87581 PY - 2019 Y1 - 2019 N2 - We are studying hyperbolic function theory in the skew-field of quaternions. This theory is connected to k-hyperbolic harmonic functions that are harmonic with respect to the hyperbolic Riemannian metric (Formula Presented) in the upper half space (Formula Presented). In the case k = 2, the metric is the hyperbolic metric of the Poincaré upper half-space. Hempfling and Leutwiler started to study this case and noticed that the quaternionic power function xm(m ε Z), is a conjugate gradient of a 2-hyperbolic harmonic function. They researched polynomial solutions. We find fundamental k-hyperbolic harmonic functions depending only on the hyperbolic distance and x3. Using these functions we are able to verify a Cauchy type integral formula. Earlier these results have been verified for quaternionic functions depending only on reduced variables (x0, x1, x2). Our functions are depending on four variables. AB - We are studying hyperbolic function theory in the skew-field of quaternions. This theory is connected to k-hyperbolic harmonic functions that are harmonic with respect to the hyperbolic Riemannian metric (Formula Presented) in the upper half space (Formula Presented). In the case k = 2, the metric is the hyperbolic metric of the Poincaré upper half-space. Hempfling and Leutwiler started to study this case and noticed that the quaternionic power function xm(m ε Z), is a conjugate gradient of a 2-hyperbolic harmonic function. They researched polynomial solutions. We find fundamental k-hyperbolic harmonic functions depending only on the hyperbolic distance and x3. Using these functions we are able to verify a Cauchy type integral formula. Earlier these results have been verified for quaternionic functions depending only on reduced variables (x0, x1, x2). Our functions are depending on four variables. KW - Clifford algebra KW - Hyperbolic Laplace operator KW - Hyperbolic metric KW - Laplace-Beltrami operator KW - Monogenic function KW - Quaternions KW - α-Hyperbolic harmonic KW - α-Hypermonogenic U2 - 10.1007/978-3-030-23854-4_2 DO - 10.1007/978-3-030-23854-4_2 M3 - Chapter SN - 978-3-030-23853-7 T3 - Trends in Mathematics SP - 25 EP - 52 BT - Topics in Clifford Analysis PB - Springer ER - TY - CHAP T1 - Robust Kalman-type filtering in positioning applications AU - Perälä, Tommi N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Chapter SN - 978-953-307-094-0 SP - 271 EP - 288 BT - Kalman Filter A2 - Kordic, Verdan PB - InTech CY - Croatia ER - TY - CHAP T1 - Soft Computing Methods AU - Turunen, Esko AU - Raivio, Kimmo AU - Mantere, Timo PY - 2016 Y1 - 2016 N2 - Soft computing methods of modelling usually include fuzzy logics , neural computation , genetical algorithms and probabilistic deduction , with the addition of data mining and chaos theory in some cases. Unlike the traditional “hardcore methods” of modelling, these new methods allow for the gained results to be incomplete or inexact. Methodologically, the different approaches of these soft methods are quite heterogeneous. Still, all of them have a few things in common, namely that they have all been developed during the last 30–50 years (Bayes formula in 1763 and Lukasiewicz logic in 1920 being the exceptions), and that they would probably have not achieved their current standards without the exceptional growth in computational capacities of computers. AB - Soft computing methods of modelling usually include fuzzy logics , neural computation , genetical algorithms and probabilistic deduction , with the addition of data mining and chaos theory in some cases. Unlike the traditional “hardcore methods” of modelling, these new methods allow for the gained results to be incomplete or inexact. Methodologically, the different approaches of these soft methods are quite heterogeneous. Still, all of them have a few things in common, namely that they have all been developed during the last 30–50 years (Bayes formula in 1763 and Lukasiewicz logic in 1920 being the exceptions), and that they would probably have not achieved their current standards without the exceptional growth in computational capacities of computers. U2 - 10.1007/978-3-319-27836-0_6 DO - 10.1007/978-3-319-27836-0_6 M3 - Chapter SN - 978-3-319-27834-6 SP - 79 EP - 112 BT - Mathematical Modelling A2 - Pohjolainen, Seppo PB - Springer International Publishing ER - TY - CHAP T1 - Teollinen internet ja semanttinen mallinnus AU - Nykänen, Ossi PY - 2017 Y1 - 2017 M3 - Chapter SN - 978-952-68687-0-7 SP - 102 EP - 123 BT - Teollinen internet uudistaa palveluliiketoimintaa ja kunnossapitoa A2 - Martinsuo, Miia A2 - Kärri, Timo PB - Kunnossapitoyhdistys ProMaint CY - Kerava ER - TY - CHAP T1 - Towards Human Cell Simulation AU - Spolaor, Simone AU - Gribaudo, Marco AU - Iacono, Mauro AU - Kadavy, Tomas AU - Komínková Oplatková, Zuzana AU - Mauri, Giancarlo AU - Pllana, Sabri AU - Senkerik, Roman AU - Stojanovic, Natalija AU - Turunen, Esko AU - Viktorin, Adam AU - Vitabile, Salvatore AU - Zamuda, Aleš AU - Nobile, Marco S. N1 - jufoid=62555 PY - 2019/3/25 Y1 - 2019/3/25 N2 - The faithful reproduction and accurate prediction of the phenotypes and emergent behaviors of complex cellular systems are among the most challenging goals in Systems Biology. Although mathematical models that describe the interactions among all biochemical processes in a cell are theoretically feasible, their simulation is generally hard because of a variety of reasons. For instance, many quantitative data (e.g., kinetic rates) are usually not available, a problem that hinders the execution of simulation algorithms as long as some parameter estimation methods are used. Though, even with a candidate parameterization, the simulation of mechanistic models could be challenging due to the extreme computational effort required. In this context, model reduction techniques and High-Performance Computing infrastructures could be leveraged to mitigate these issues. In addition, as cellular processes are characterized by multiple scales of temporal and spatial organization, novel hybrid simulators able to harmonize different modeling approaches (e.g., logic-based, constraint-based, continuous deterministic, discrete stochastic, spatial) should be designed. This chapter describes a putative unified approach to tackle these challenging tasks, hopefully paving the way to the definition of large-scale comprehensive models that aim at the comprehension of the cell behavior by means of computational tools. AB - The faithful reproduction and accurate prediction of the phenotypes and emergent behaviors of complex cellular systems are among the most challenging goals in Systems Biology. Although mathematical models that describe the interactions among all biochemical processes in a cell are theoretically feasible, their simulation is generally hard because of a variety of reasons. For instance, many quantitative data (e.g., kinetic rates) are usually not available, a problem that hinders the execution of simulation algorithms as long as some parameter estimation methods are used. Though, even with a candidate parameterization, the simulation of mechanistic models could be challenging due to the extreme computational effort required. In this context, model reduction techniques and High-Performance Computing infrastructures could be leveraged to mitigate these issues. In addition, as cellular processes are characterized by multiple scales of temporal and spatial organization, novel hybrid simulators able to harmonize different modeling approaches (e.g., logic-based, constraint-based, continuous deterministic, discrete stochastic, spatial) should be designed. This chapter describes a putative unified approach to tackle these challenging tasks, hopefully paving the way to the definition of large-scale comprehensive models that aim at the comprehension of the cell behavior by means of computational tools. U2 - 10.1007/978-3-030-16272-6_8 DO - 10.1007/978-3-030-16272-6_8 M3 - Chapter SN - 978-3-030-16271-9 T3 - Lecture Notes in Computer Science SP - 221 EP - 249 BT - High-Performance Modelling and Simulation for Big Data Applications A2 - Kolodziej, Joanna A2 - Gonzalez-Velez, Horacio PB - Springer Verlag ER - TY - CHAP T1 - Two Consistent Many-Valued Logics for Paraconsistent Phenomena AU - Turunen, Esko AU - Rodrigues, J. Tinguaro N1 - JUFOID=84290 PY - 2016/3/9 Y1 - 2016/3/9 U2 - 10.1007/978-81-322-2719-9 DO - 10.1007/978-81-322-2719-9 M3 - Chapter SN - 978-81-322-2717-5 T3 - Springer Proceedings in Mathematics & Statistics SP - 185 EP - 210 BT - New Directions in Paraconsistent Logic A2 - Beziau, Jean-Yves A2 - Chakraborty, Mihir A2 - Dutta, Soma PB - Springer Verlag CY - New Delhi Heidelberg New York Dordrecht London ER - TY - CHAP T1 - Verkostoanalyysi sosiaalisen median tutkimuksessa AU - Huhtamäki, Jukka AU - Parviainen, Olli N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29 PY - 2013 Y1 - 2013 M3 - Chapter SN - 978-951-768-410-1 SP - 245 EP - 273 BT - Otteita verkosta - verkon ja sosiaalisen median tutkimusmenetelmät A2 - Laaksonen, Salla-Maaria A2 - Matikainen, Janne A2 - Tikka, Minttu PB - Vastapaino CY - Tampere ER - TY - CHAP T1 - What’s out there? Asteroid models for target selection and mission planning AU - Kaasalainen, Mikko AU - Durech, Josef N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29 PY - 2013 Y1 - 2013 U2 - 10.1007/978-3-642-39244-3 DO - 10.1007/978-3-642-39244-3 M3 - Chapter SN - 978-3-642-39243-6 SP - 131 EP - 150 BT - Asteroids: prospective energy and material resources A2 - Badescu, Viorel PB - Springer CY - Heidelberg ER - TY - CHAP T1 - Engineering Mathematics Education in Finland T2 - A Comparative Analysis of EU, Russia, Georgia and Armenia AU - Pohjolainen, Seppo AU - Myllykoski, Tuomas PY - 2018 Y1 - 2018 M3 - Chapter SN - 978-3-319-71415-8 SP - 69 EP - 75 BT - Modern Mathematics Education for Engineering Curricula in Europe A2 - Pohjolainen, Seppo A2 - Myllykoski, Tuomas A2 - Mercat, Christian A2 - Sosnovsky, Sergey PB - Birkhäuser ER - TY - CHAP T1 - Matematiikan oppimisen tukeminen teknillisessä yliopistokoulutuksessa AU - Pohjolainen, Seppo AU - Rasila, Antti AU - Kuosa, Kirsi PY - 2018 Y1 - 2018 KW - mathematics education KW - mathematics teaching KW - mathematics learning M3 - Chapter SN - 978-951-39-7584-5 SP - 450 EP - 474 BT - Matematiikan opetus ja oppiminen A2 - Joutsenlahti, Jorma A2 - Silfverberg, Harry A2 - Räsänen, Pekka PB - Niilo Mäki Instituutti CY - Porvoo ER - TY - CHAP T1 - Matematiikkaklinikka AU - Kangas, Jussi N1 - Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Chapter SN - 978-952-60-4185-8 SP - 56 EP - 60 BT - Oppaiden opas - vinkkejä opetukseen opintopolun eri vaiheissa. Aalto-yliopiston julkaisusarja Tiede + Teknologia A2 - Myller, Eeva PB - Aalto-yliopisto CY - Helsinki ER - TY - CHAP T1 - Miten opiskella matematiikkaa yliopistossa - opas opiskelijoille AU - Kailanto, Meri N1 - Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Chapter SN - 978-952-60-4185-8 SP - 53 EP - 55 BT - Oppaiden opas - vinkkejä opetukseen opintopolun eri vaiheissa. Aalto-yliopiston julkaisusarja Tiede + Teknologia A2 - Myller, Eeva PB - Aalto-yliopisto CY - Helsinki ER - TY - GEN T1 - A New Method and Format for Describing CANopen System Topology AU - Helminen, Matti AU - Salonen, Jaakko AU - Saha, Heikki AU - Nykänen, Ossi AU - Koskinen, Kari T. AU - Ranta, Pekka AU - Pohjolainen, Seppo N1 - ei ut-numeroa 13.8.2013

Contribution: organisation=iha,FACT1=0.6

Contribution: organisation=mat,FACT2=0.4

Publisher name: CAN in Automation e.V. PY - 2012 Y1 - 2012 M3 - Conference contribution T3 - International CAN Conference SP - 1 EP - 8 BT - Proceedings of the 13th International CAN Conference, iCC 2012 in Hambach Castle, March 5 to March 6, Germany PB - CAN in Automation e.V. ER - TY - GEN T1 - A Stochastic Mixture Surrogate Model Algorithm for Computationally Expensive Black-Box Global Optimization Problems AU - Müller, Juliane AU - Shoemaker, Christine AU - Piche, Robert N1 - ei ut-numeroa 22.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Universidade Federal do Rio Grande do Norte PY - 2012 Y1 - 2012 M3 - Conference contribution T3 - Global Optimization Workshop SP - 1 EP - 4 BT - Proceedings of Global Optimization Workshop 2012, 26-29 June 2012, Natal, Brazil PB - Universidade Federal do Rio Grande do Norte CY - Natal, Brazil ER - TY - GEN T1 - Autonomous satellite orbit prediction AU - Seppänen, Mari N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 N2 - A method to predict satellite orbits in a GPS device without a network connection is presented. The motivation for this work was to improve the startup performance of a navigation device without Assisted GPS. Tests of our algorithm show that in 95% of the cases the error in satellite’s predicted position stays under 21 meters for one day and under 94 meters for three days. AB - A method to predict satellite orbits in a GPS device without a network connection is presented. The motivation for this work was to improve the startup performance of a navigation device without Assisted GPS. Tests of our algorithm show that in 95% of the cases the error in satellite’s predicted position stays under 21 meters for one day and under 94 meters for three days. M3 - Conference contribution SN - 978-952-15-2557-5 T3 - TISE Seminar SP - 5 EP - 10 BT - Digest of TISE Seminar 2011. TISE publications A2 - Niemistö, Antti PB - Tampere Graduate School in Information Science and Engineering (TISE). Tampere University of Technology CY - Tampere ER - TY - GEN T1 - Autonomous satellite orbit prediction AU - Seppänen, Mari AU - Perälä, Tommi AU - Piche, Robert N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 N2 - A method to predict satellite orbits in a GPS device without a network connection is presented. The motivation for this work was to reduce time to first fix when assistance data is not available. The orbit of a satellite is predicted by numerically integrating the differential equation that models its motion. The initial position and velocity values used in prediction correspond to those received from the broadcast when the device was last operated. These initial values are given in the Earth centered, Earth fixed reference frame and have to be transformed into an inertial reference frame prior to substitution into the equation of motion and subsequent integration. For this purpose, one needs to predict the movement of Earth’s rotation axis with respect to both space (nutation and precession) and to the Earth’s crust (polar motion). Using precise ephemeris as the initial condition, we found that this kind of model gave quite accurate prediction results. However, the results were worse when initial conditions were computed from the less accurate broadcast ephemeris which, unfortunately, is the only ephemeris available to the navigation device without a network connection. In addition, we were not able to find a model that would be able to predict Earth’s polar motion with sufficient accuracy within the assumed lifetime of the device. Without the polar motion parameters, one cannot do the transformation from ECEF to an inertial reference frame. In this paper we will present a method to improve the accuracy of the initial velocity of the satellite computed from the broadcast and simultaneously solve the unknown polar motion parameters. Tests of our algorithm show that in 95%of the cases the error in satellite’s predicted position stays under 21 meters for one day and under 94 meters for three days. AB - A method to predict satellite orbits in a GPS device without a network connection is presented. The motivation for this work was to reduce time to first fix when assistance data is not available. The orbit of a satellite is predicted by numerically integrating the differential equation that models its motion. The initial position and velocity values used in prediction correspond to those received from the broadcast when the device was last operated. These initial values are given in the Earth centered, Earth fixed reference frame and have to be transformed into an inertial reference frame prior to substitution into the equation of motion and subsequent integration. For this purpose, one needs to predict the movement of Earth’s rotation axis with respect to both space (nutation and precession) and to the Earth’s crust (polar motion). Using precise ephemeris as the initial condition, we found that this kind of model gave quite accurate prediction results. However, the results were worse when initial conditions were computed from the less accurate broadcast ephemeris which, unfortunately, is the only ephemeris available to the navigation device without a network connection. In addition, we were not able to find a model that would be able to predict Earth’s polar motion with sufficient accuracy within the assumed lifetime of the device. Without the polar motion parameters, one cannot do the transformation from ECEF to an inertial reference frame. In this paper we will present a method to improve the accuracy of the initial velocity of the satellite computed from the broadcast and simultaneously solve the unknown polar motion parameters. Tests of our algorithm show that in 95%of the cases the error in satellite’s predicted position stays under 21 meters for one day and under 94 meters for three days. M3 - Conference contribution T3 - Institute of Navigation International Technical Meeting SP - 554 EP - 564 BT - Proceedings of The Institute of Navigation 2011 International Technical Meeting, January 24-26, 2011, San Diego, CA, USA PB - The Institute of Navigation CY - San Diego, CA ER - TY - GEN T1 - Bayesian Positioning Using Gaussian Mixture Models with Time-varying Component Weights AU - Pesonen, Henri AU - Piche, Robert N1 - ei ut-numeroa 26.4.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 N2 - Gaussian mixture models are often used in target tracking applications to take into account maneuvers in state dynamics or changing levels of observation noise. In this study it is assumed that the measurement or the state transition model can have two plausible candidates, as for example in positioning with line-of-sight or non-line-sight-signals. The plausibility described by the mixture component weight is modeled as a time-dependent random variable and is formulated as a Markov process with a heuristic model based on the Beta distribution. The proposed system can be used to approximate some well-known multiple model systems by tuning the parameter of the state transition distribution for the component weight. The posterior distribution of the state can be solved approximately using a Rao-Blackwellized particle filter. Simulations of GPS pedestrian tracking are used to test the proposed method. The results indicate that the new system is able to find the true models and its root mean square error-performance is comparable to filters that know the true models. AB - Gaussian mixture models are often used in target tracking applications to take into account maneuvers in state dynamics or changing levels of observation noise. In this study it is assumed that the measurement or the state transition model can have two plausible candidates, as for example in positioning with line-of-sight or non-line-sight-signals. The plausibility described by the mixture component weight is modeled as a time-dependent random variable and is formulated as a Markov process with a heuristic model based on the Beta distribution. The proposed system can be used to approximate some well-known multiple model systems by tuning the parameter of the state transition distribution for the component weight. The posterior distribution of the state can be solved approximately using a Rao-Blackwellized particle filter. Simulations of GPS pedestrian tracking are used to test the proposed method. The results indicate that the new system is able to find the true models and its root mean square error-performance is comparable to filters that know the true models. M3 - Conference contribution T3 - Joint Statistical Meetings JSM SP - 4516 EP - 4524 BT - JSM 2011 Joint Statistical Meetings 2011, Miami Beach, Florida, USA, July 30-August 4, 2011 PB - American Statistical Association CY - Miami Beach, FL ER - TY - GEN T1 - Briefly about the root-locus of linear systems AU - Laakkonen, Petteri N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Conference contribution SN - 978-952-15-2368-7 SP - 101 EP - 106 BT - Digest of TISE Seminar 2010, Ylöjärvi, Finland, 26.5.2010. TISE Publications A2 - Koivisto, Pertti ER - TY - GEN T1 - Characterizing n-Fold Positive Implicative BL-logics AU - Turunen, Esko AU - Lele, Celestin AU - Tchikapa, Ngentau N1 - ei ut-numeroa 21.9.2013

Contribution: organisation=mat,FACT1=1 PY - 2012 Y1 - 2012 M3 - Conference contribution T3 - ManyVal SP - 60 EP - 64 BT - ManyVal'12 In Honour of Antonio Di Nola's 65th Birthday, Salerno, Italy, 4.7.7.2012 ER - TY - GEN T1 - Gaussian mixture filter in hybrid navigation AU - Ali-Löytty, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2007 Y1 - 2007 M3 - Conference contribution SP - 1 EP - 5 BT - Digest of TISE Seminar 2007, Nokia, Finland, 5 June 2007 A2 - Koivisto, P. ER - TY - GEN T1 - Mobile tracking in unknown non-line-of-sight conditions AU - Liang, Chen AU - Pesonen, Henri AU - Piche, Robert N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 N2 - This paper studies the mobile tracking problem in mixed line-of-sight (LOS) and non-line-of-sight (NLOS) conditions, where the statistics of NLOS error are assumed unknown. Three different models are used to describe the NLOS errors. A Rao-Blackwellized particle filtering with parameter learning (RBPF-PL) is presented, in which the posterior of sight conditions is estimated by particle filtering while the mobile state and NLOS parameters are analytically computed. Simulation results are provided to evaluate the performance of RBPF-PL variants in different situations. Simulation show that unless it is known that NLOS noise has the same bias and variance in all the observations, the more complicated models should be employed as they work correctly even in NLOS model mismatch, with only slightly more computational complexity. AB - This paper studies the mobile tracking problem in mixed line-of-sight (LOS) and non-line-of-sight (NLOS) conditions, where the statistics of NLOS error are assumed unknown. Three different models are used to describe the NLOS errors. A Rao-Blackwellized particle filtering with parameter learning (RBPF-PL) is presented, in which the posterior of sight conditions is estimated by particle filtering while the mobile state and NLOS parameters are analytically computed. Simulation results are provided to evaluate the performance of RBPF-PL variants in different situations. Simulation show that unless it is known that NLOS noise has the same bias and variance in all the observations, the more complicated models should be employed as they work correctly even in NLOS model mismatch, with only slightly more computational complexity. U2 - 10.1109/UPINLBS.2010.5654324 DO - 10.1109/UPINLBS.2010.5654324 M3 - Conference contribution SN - 978-1-4244-7879-8 SP - 1 EP - 4 BT - Proceedings of the International Conference on Ubiquitous Positioning, Indoor Navigation and Location-Based Service UPINLBS 2010, October 14-15, 2010, Kirkkonummi, Finland CY - Helsinki ER - TY - GEN T1 - Periodic output regulation of infinite-dimensional systems AU - Paunonen, Lassi N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Conference contribution SN - 978-952-15-2368-7 SP - 113 EP - 118 BT - Digest of TISE Seminar 2010, Ylöjärvi, Finland, 26.5.2010. TISE Publications A2 - Koivisto, Pertti ER - TY - GEN T1 - Robust output regulation and the internal model principle AU - Paunonen, Lassi N1 - ei ut-numeroa 26.4.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution SN - 978-952-15-2557-5 T3 - TISE Seminar SP - 71 EP - 75 BT - Digest of TISE Seminar 2011. TISE publications A2 - Niemistö, Antti PB - Tampere Graduate School in Information Science and Engineering (TISE). Tampere University of Technology CY - Tampere ER - TY - GEN T1 - Robust regulation: From state-space to frequency domain AU - Laakkonen, Petteri N1 - ei ut-numeroa 20.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Tampere Graduate School in Information Science and Engineering (TISE). Tampere University of Technology, University of Tampere PY - 2012 Y1 - 2012 M3 - Conference contribution SN - 978-952-15-2845-3 T3 - TISE Seminar SP - 135 EP - 140 BT - Digest of TISE Seminar 2012, Nokia, Finland, 14 June, 2012. TISE Publications A2 - Niemistö, Antti PB - Tampere Graduate School in Information Science and Engineering (TISE). Tampere University of Technology, University of Tampere CY - Tampere ER - TY - GEN T1 - Sitikka - motivointia matematiikan opiskeluun AU - Talvitie, Jukka AU - Valkama, Mikko AU - Huttunen, Heikki AU - Laaksonen, Merja N1 - Contribution: organisation=tlt,FACT1=0.34

Contribution: organisation=sgn,FACT2=0.33

Contribution: organisation=mat,FACT3=0.33 PY - 2010 Y1 - 2010 M3 - Conference contribution SP - 156 EP - 158 BT - Tekniikan opetuksen symposium, 9.-10.12.2010, Dipoli, Espoo. Dipoli-raportit B ER - TY - GEN T1 - Studying the quality of noise in a large biochemical reaction network as a function of the system volume AU - Intosalmi, Jukka AU - Manninen, Tiina AU - Ruohonen, Keijo AU - Linne, Marja-Leena N1 - ei ut-numeroa 15.3.2014

Contribution: organisation=sgn,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5 PY - 2011 Y1 - 2011 M3 - Conference contribution T3 - International Conference on Applied Mathematics, Modeling and Computational Science AMMCS SP - 409 BT - The International Conference on Applied Mathematics, Modeling and Computational Science, AMMCS 2011, 25 - 29 July, Waterloo, Ontario, Canada PB - AMMCS 2011 CY - Waterloo, Ontario, Canada ER - TY - GEN T1 - The root-locus analysis: An outline AU - Laakkonen, Petteri N1 - ei ut-numeroa 29.3.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution SN - 978-952-15-2557-5 T3 - TISE Seminar SP - 1 EP - 4 BT - TISE Seminar 2011, Tampere, 25.5.2011. Digest of TISE Seminar 2011 A2 - Niemistö, Antti PB - Tampere Graduate School in Information Science and Engineering (TISE). Tampere University of Technology CY - Tampere ER - TY - GEN T1 - A case study of focal bayesian EEG inversion for whitney element source spaces T2 - Mesh-based vs. cartesian orientations AU - Miinalainen, T. AU - Pursiainen, S. N1 - jufoid=58152 PY - 2018 Y1 - 2018 N2 - This paper concentrates on the Bayesian detection of the neuronal current distributions in the electroencephalography (EEG) imaging of the brain activity. In particular, we focus on a hierarchical maximum a posteriori inversion technique applicable when the lead field matrix is constructed via the finite element method. We utilize the linear Whitney (Raviart-Thomas) basis functions as source currents. In the numerical experiments, the accuracy was investigated using two spherical head models. The results obtained suggest that the interpolation of the dipolar source space does not necessarily bring any advantage for FEM based inverse computations. Furthermore, the divergence conforming Whitney-type sources were found to be sufficient for precise and highly focal Bayesian modeling of dipole-like currents. AB - This paper concentrates on the Bayesian detection of the neuronal current distributions in the electroencephalography (EEG) imaging of the brain activity. In particular, we focus on a hierarchical maximum a posteriori inversion technique applicable when the lead field matrix is constructed via the finite element method. We utilize the linear Whitney (Raviart-Thomas) basis functions as source currents. In the numerical experiments, the accuracy was investigated using two spherical head models. The results obtained suggest that the interpolation of the dipolar source space does not necessarily bring any advantage for FEM based inverse computations. Furthermore, the divergence conforming Whitney-type sources were found to be sufficient for precise and highly focal Bayesian modeling of dipole-like currents. KW - Electroencephalography (EEG) KW - Finite element method (FEM) KW - Hierarchical Bayesian inverse model KW - Whitney elements U2 - 10.1007/978-981-10-5122-7_266 DO - 10.1007/978-981-10-5122-7_266 M3 - Conference contribution SN - 9789811051210 T3 - IFMBE Proceedings SP - 1065 EP - 1068 BT - EMBEC and NBC 2017 - Joint Conference of the European Medical and Biological Engineering Conference EMBEC 2017 and the Nordic-Baltic Conference on Biomedical Engineering and Medical Physics, NBC 2017 PB - Springer Verlag ER - TY - GEN T1 - Accelerated simulation of a neuronal population via mathematical model order reduction AU - Lehtimäki, Mikko AU - Seppälä, Ippa AU - Paunonen, Lassi AU - Linne, Marja-Leena N1 - INT=bmte,"Seppälä, Ippa" PY - 2020 Y1 - 2020 N2 - Mathematical modeling of biological neuronal networks is important in order to increase understanding of the brain and develop systems capable of brain-like learning. While mathematical analysis of these comprehensive, stochastic, and complex models is intractable, and their numerical simulation is very resource intensive, mean-field modeling is an effective tool in enabling the analysis of these models. The mean-field approach allows the study of populations of biophysically detailed neurons with some assumptions of the mean behaviour of the population, but ultimately requires numerical solving of highdimensional differential equation systems. Mathematical model order reduction methods can be employed to accelerate the analysis of high-dimensional nonlinear models with a purely softwarebased approach. Here we compare state-of-the-art methods for improving the simulation time of a neuronal mean-field model and show that a nonlinear Fokker-Planck-McKean-Vlasov model can be accurately approximated in low-dimensional subspaces with these methods. Using Proper Orthogonal Decomposition and different variations of the Discrete Empirical Interpolation Method, we improved the simulation time by over three orders of magnitude while achieving low approximation error. AB - Mathematical modeling of biological neuronal networks is important in order to increase understanding of the brain and develop systems capable of brain-like learning. While mathematical analysis of these comprehensive, stochastic, and complex models is intractable, and their numerical simulation is very resource intensive, mean-field modeling is an effective tool in enabling the analysis of these models. The mean-field approach allows the study of populations of biophysically detailed neurons with some assumptions of the mean behaviour of the population, but ultimately requires numerical solving of highdimensional differential equation systems. Mathematical model order reduction methods can be employed to accelerate the analysis of high-dimensional nonlinear models with a purely softwarebased approach. Here we compare state-of-the-art methods for improving the simulation time of a neuronal mean-field model and show that a nonlinear Fokker-Planck-McKean-Vlasov model can be accurately approximated in low-dimensional subspaces with these methods. Using Proper Orthogonal Decomposition and different variations of the Discrete Empirical Interpolation Method, we improved the simulation time by over three orders of magnitude while achieving low approximation error. U2 - 10.1109/AICAS48895.2020.9073844 DO - 10.1109/AICAS48895.2020.9073844 M3 - Conference contribution SN - 978-1-7281-4923-3 SP - 118 EP - 122 BT - 2020 2nd IEEE International Conference on Artificial Intelligence Circuits and Systems (AICAS) PB - IEEE ER - TY - GEN T1 - A field test of parametric WLAN-fingerprint-positioning methods AU - Muller, Philip AU - Raitoharju, Matti AU - Piche, Robert N1 - The paper is available in ieeexplore, and will later also appear at http://isif.org/content/conference-proceedings

Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2014-11-21 PY - 2014 Y1 - 2014 M3 - Conference contribution SN - 978-84-9012-355-3 SP - 1 EP - 8 BT - 17th International Conference on Information Fusion (FUSION), 7-10 July 2014, Salamanca, Spain PB - Institute of Electrical and Electronics Engineers CY - Piscataway ER - TY - GEN T1 - Algorithms and Logic as Programming Primers AU - Niemelä, Pia AU - Valmari, Antti AU - Ali-Löytty, Simo N1 - jufoid=53801 EXT="Valmari, Antti" PY - 2019/6 Y1 - 2019/6 N2 - To adapt all-immersive digitalization, the Finnish National Curriculum 2014 (FNC-2014) ‘digi-jumps’ by integrating programming into elementary education. However, applying the change to mathematics teachers’ everyday praxis is hindered by a too high-level specification. To elaborate FNC-2014 into more concrete learning targets, we review the computer science syllabi of countries that are well ahead, as well as the education recommendations set by computer science organizations, such as ACM and IEEE. The whole mathematics syllabus should be critically viewed in the light of these recommendations and feedback collected from software professionals and educators. The feedback reveals an imbalance between supply and demand, i.e., what is over-taught versus under-taught, from the point of the requirements of current working life. The surveyed software engineers criticize the unnecessary surplus of calculus and differential equations, i.e., continuous mathematics. In contrast, the emphasis should shift more towards algorithms and data structures, flexibility in handling multiple data representations, and logic: in short – discrete mathematics. The ground for discrete mathematics should be prepared early enough, started already from primary level and continued consistently throughout the secondary till tertiary education. This paper aims to contribute to the further refinement of the mathematics syllabus by proposing such a discrete mathematics subset that especially supports the needs of computer science education, the focus being on algorithms and data structures, and logic in particular. AB - To adapt all-immersive digitalization, the Finnish National Curriculum 2014 (FNC-2014) ‘digi-jumps’ by integrating programming into elementary education. However, applying the change to mathematics teachers’ everyday praxis is hindered by a too high-level specification. To elaborate FNC-2014 into more concrete learning targets, we review the computer science syllabi of countries that are well ahead, as well as the education recommendations set by computer science organizations, such as ACM and IEEE. The whole mathematics syllabus should be critically viewed in the light of these recommendations and feedback collected from software professionals and educators. The feedback reveals an imbalance between supply and demand, i.e., what is over-taught versus under-taught, from the point of the requirements of current working life. The surveyed software engineers criticize the unnecessary surplus of calculus and differential equations, i.e., continuous mathematics. In contrast, the emphasis should shift more towards algorithms and data structures, flexibility in handling multiple data representations, and logic: in short – discrete mathematics. The ground for discrete mathematics should be prepared early enough, started already from primary level and continued consistently throughout the secondary till tertiary education. This paper aims to contribute to the further refinement of the mathematics syllabus by proposing such a discrete mathematics subset that especially supports the needs of computer science education, the focus being on algorithms and data structures, and logic in particular. KW - Computational thinking KW - algorithms KW - logic U2 - 10.1007/978-3-030-21151-6_18 DO - 10.1007/978-3-030-21151-6_18 M3 - Conference contribution SN - 9783030211509 T3 - Communications in Computer and Information Science SP - 357 EP - 383 BT - Computer Supported Education PB - Springer Nature ER - TY - GEN T1 - A linear state model for PDR+WLAN positioning AU - Raitoharju, Matti AU - Nurminen, Henri AU - Piche, Robert N1 - to appear in IEEEXPLORE

Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2013-10-29 PY - 2013 Y1 - 2013 N2 - Indoor positioning based on WLAN signals is often enhanced using pedestrian dead reckoning (PDR) based on an inertial measurement unit. The state evolution model in PDR is usually nonlinear. We present a new linear state evolution model for PDR. In simulated-data and real-data tests of tightly coupled WLAN-PDR positioning, we find that the positioning accuracy with this linear model is almost as good as with traditional models when the initial state is known, and better when the initial state is not known. The proposed method is computationally light and is also suitable for smoothing. AB - Indoor positioning based on WLAN signals is often enhanced using pedestrian dead reckoning (PDR) based on an inertial measurement unit. The state evolution model in PDR is usually nonlinear. We present a new linear state evolution model for PDR. In simulated-data and real-data tests of tightly coupled WLAN-PDR positioning, we find that the positioning accuracy with this linear model is almost as good as with traditional models when the initial state is known, and better when the initial state is not known. The proposed method is computationally light and is also suitable for smoothing. M3 - Conference contribution SN - 979-10-92279-02-3 T3 - Conference on Design and Architectures for Signal and Image Processing SP - 113 EP - 118 BT - Proceedings of the 2013 Conference on Design and Architectures for Signal and Image Processing DASIP Cagliari, Italy, October 8-10, 2013 A2 - Morawiec, Adam A2 - Hinderscheit, Jinnie PB - European Electronic Chips & Systems Design Initiative (ECSI) CY - Belmont France ER - TY - GEN T1 - Alumni Network Analysis AU - Rubens, Neil AU - Russell, Martha G. AU - Perez, Rafael AU - Huhtamäki, Jukka AU - Still, Kaisa AU - Kaplan, Dain AU - Okamoto, Toshio N1 - ei ut-numeroa 5.3.2014

Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 U2 - 10.1109/EDUCON.2011.5773200 DO - 10.1109/EDUCON.2011.5773200 M3 - Conference contribution SN - 978-1-61284-642-2 T3 - IEEE Global Engineering Education Conference EDUCON SP - 606 EP - 611 BT - 2011 IEEE 2nd Global Engineering Education Conference EDUCON, 4-6 April 2011, Amman, Jordan PB - IEEE CY - Piscataway, NJ ER - TY - GEN T1 - A method to enforce map constraints in a particle filter's position estimate AU - Piche, Robert AU - Koivisto, Mike N1 - Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2014-09-05

Publisher name: IEEE PY - 2014 Y1 - 2014 U2 - 10.1109/WPNC.2014.6843284 DO - 10.1109/WPNC.2014.6843284 M3 - Conference contribution BT - 2014 11th Workshop on Positioning, Navigation and Communication (WPNC), 12-13 March 2014, Dresden, Germany PB - IEEE ER - TY - GEN T1 - A motion model for articulated vehicles and a distributed acceleration measurement system AU - Sirola, Niilo AU - Rouhe, Jarkko N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1109/WPNC.2010.5650556 DO - 10.1109/WPNC.2010.5650556 M3 - Conference contribution SN - 978-1-4244-7157-7 SP - 164 EP - 167 BT - Proceedings of the 7th Workshop on Positioning, Navigation and Communication 2010 WPNC'10, 11-12 March 2010, Dresden, Germany ER - TY - GEN T1 - An empirical solar radiation pressure model for autonomous GNSS orbit prediction AU - Ala-Luhtala, Juha AU - Seppänen, Mari AU - Piche, Robert N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Electrical and Electronics Engineers IEEE PY - 2012 Y1 - 2012 N2 - GNSS satellite orbits can be predicted by integrating the satellites’ equation of motion. If the prediction is done in a consumer grade positioning device, a simplified version of the equation of motion is required. The forces due to Earth’s gravitation, solar gravitation and lunar gravitation should be included, but the models for the smaller non-gravitational forces can be fairly simple. This paper presents a simple empirical two parameter solar radiation pressure model for an orbit prediction application in a navigation device that does not have a network connection. The model is tested by predicting the orbits of GPS and GLONASS satellites up to 5 days into the future, using position and improved velocity from broadcast ephemerides as an initial state. The predicted orbits are compared to the precise orbits from International GNSS Service (IGS). AB - GNSS satellite orbits can be predicted by integrating the satellites’ equation of motion. If the prediction is done in a consumer grade positioning device, a simplified version of the equation of motion is required. The forces due to Earth’s gravitation, solar gravitation and lunar gravitation should be included, but the models for the smaller non-gravitational forces can be fairly simple. This paper presents a simple empirical two parameter solar radiation pressure model for an orbit prediction application in a navigation device that does not have a network connection. The model is tested by predicting the orbits of GPS and GLONASS satellites up to 5 days into the future, using position and improved velocity from broadcast ephemerides as an initial state. The predicted orbits are compared to the precise orbits from International GNSS Service (IGS). U2 - 10.1109/PLANS.2012.6236929 DO - 10.1109/PLANS.2012.6236929 M3 - Conference contribution SN - 978-1-4673-0385-9 T3 - IEEE/ION Position Location and Navigation Symposium SP - 568 EP - 575 BT - 2012 IEEE/ION Position Location and Navigation Symposium PLANS, 23-26 April 2012, Myrtle Beach, SC, USA PB - Institute of Electrical and Electronics Engineers IEEE CY - Piscataway, NJ ER - TY - GEN T1 - A Network-Centric Snapshot of Value Co-Creation in Finnish Innovation Financing AU - Huhtamäki, Jukka AU - Russell, Martha G. AU - Still, Kaisa AU - Rubens, Neil N1 - ei ut-numeroa 8.3.2014

Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution SN - 978-952-15-2529-2 T3 - Research Forum to Understand Business in Knowledge Society EBRF SP - 1 EP - 15 BT - EBRF 2010, Research Forum to Understand Business in Knowledge Society, September 15-17, 2010, Nokia, Finland A2 - Seppä, Marko A2 - Helander, Nina A2 - Ilvonen, Ilona PB - GVL Finland CY - Nokia ER - TY - GEN T1 - A New Cauchy Type Integral Formula for Quaternionic k-hypermonogenic Functions AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - EXT="Eriksson, Sirkka-Liisa" PY - 2016/11/23 Y1 - 2016/11/23 N2 - In complex function theory holomorphic functions are conjugate gradient of real harmonic functions. We may build function theories in higher dimensions based on this idea if we generalize harmonic functions and define the conjugate gradient operator. We study this type of function theory in R3 connected to harmonic functions with respect to the Laplace–Beltrami operator of the Riemannian metric ds2=x−2k2(∑2i=0dx2i). The domain of the definition of our functions is in R3 and the image space is the associative algebra of quaternions H generated by 1, e1, e2 and e12 = e1e2 satisfying the relation e i e j + e j e i = –2δ ij , i, j = 1, 2. The complex field C is identified by the set {x0+x1e1|x0,x1εB}. The conjugate gradient is defined in terms of modified Dirac operator, introduced by Mkf=Df+kx−12Qf¯¯¯¯¯¯¯, where Qf is given by the decomposition f (x) = Pf (x) + Qf (x) e2 with Pf (x) and Qf (x) in C and Qf¯¯¯¯¯¯¯ is the usual complex conjugation.Leutwiler noticed around 1990 that if the usual Euclidean metric is changed to the hyperbolic metric of the Poincaré upper half-space model (k = 1), then the power function (x0 + x1e1 + x2e2) n , calculated using quaternions, is the conjugate gradient of the a hyperbolic harmonic function. We study functions, called k-hypermonogenic, satisfying M k f = 0. Monogenic functions are 0-hypermonogenic. Moreover, 1-hypermonogenic functions are hypermonogenic defined by H. Leutwiler and the first author.We prove a new Cauchy type integral formulas for k-hypermonogenic functions where the kernels are calculated using the hyperbolic distance and are k-hypermonogenic functions. This formula gives the known formulas in case of monogenic and hypermonogenic functions. It also produces new Cauchy and Teodorescu type integral operators investigated in the future research. AB - In complex function theory holomorphic functions are conjugate gradient of real harmonic functions. We may build function theories in higher dimensions based on this idea if we generalize harmonic functions and define the conjugate gradient operator. We study this type of function theory in R3 connected to harmonic functions with respect to the Laplace–Beltrami operator of the Riemannian metric ds2=x−2k2(∑2i=0dx2i). The domain of the definition of our functions is in R3 and the image space is the associative algebra of quaternions H generated by 1, e1, e2 and e12 = e1e2 satisfying the relation e i e j + e j e i = –2δ ij , i, j = 1, 2. The complex field C is identified by the set {x0+x1e1|x0,x1εB}. The conjugate gradient is defined in terms of modified Dirac operator, introduced by Mkf=Df+kx−12Qf¯¯¯¯¯¯¯, where Qf is given by the decomposition f (x) = Pf (x) + Qf (x) e2 with Pf (x) and Qf (x) in C and Qf¯¯¯¯¯¯¯ is the usual complex conjugation.Leutwiler noticed around 1990 that if the usual Euclidean metric is changed to the hyperbolic metric of the Poincaré upper half-space model (k = 1), then the power function (x0 + x1e1 + x2e2) n , calculated using quaternions, is the conjugate gradient of the a hyperbolic harmonic function. We study functions, called k-hypermonogenic, satisfying M k f = 0. Monogenic functions are 0-hypermonogenic. Moreover, 1-hypermonogenic functions are hypermonogenic defined by H. Leutwiler and the first author.We prove a new Cauchy type integral formulas for k-hypermonogenic functions where the kernels are calculated using the hyperbolic distance and are k-hypermonogenic functions. This formula gives the known formulas in case of monogenic and hypermonogenic functions. It also produces new Cauchy and Teodorescu type integral operators investigated in the future research. U2 - 10.1007/978-3-319-42529-0_9 DO - 10.1007/978-3-319-42529-0_9 M3 - Conference contribution SN - 978-3-319-42528-3 T3 - Trends in Mathematics SP - 175 EP - 189 BT - Modern Trends in Hypercomplex Analysis A2 - Bernstein, Swanhild A2 - Kähler, Uwe A2 - Sabadini, Irene A2 - Sommen, Franciscus PB - Springer International Publishing ER - TY - GEN T1 - A New Characterization for n-Fold Positive Implicative BL-logics AU - Turunen, Esko AU - Tchikapa, Nganteu AU - Lele, Celestin N1 - ei ut-numeroa 21.9.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Springer PY - 2012 Y1 - 2012 U2 - 10.1007/978-3-642-31709-5_56 DO - 10.1007/978-3-642-31709-5_56 M3 - Conference contribution SN - 978-3-642-31708-8 T3 - International Conference on Information Processing and Management of Uncertainty in Knowledge-Based Systems SP - 552 EP - 560 BT - Advances on Computational Intelligence 14th International Conference on Information Processing and Management of Uncertainty in Knowledge-Based Systems, IPMU 2012, Catania, Italy, July 9-13, 2012. Proceedings, Part I. Communications in Computer and Information Science A2 - Greco, Salvatore A2 - Bouchon-Meunier, Bernadette A2 - Coletti, Giulianella A2 - Fedrizzi, Mario A2 - Matarazzo, Benedetto A2 - Yager, Ronald R. PB - Springer CY - Berlin Heidelberg ER - TY - GEN T1 - A New Controller Structure for Robust Output Regulation AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-18

Publisher name: IEEE PY - 2014 Y1 - 2014 M3 - Conference contribution SN - 978-1-4673-6088-3 T3 - IEEE Conference on Decision and Control SP - 4721 EP - 4726 BT - Proceedings of the 53rd IEEE Conference on Decision and Control, IEEE CDC 2014, 15-17 December, 2014, Los Angeles, CA, USA PB - IEEE ER - TY - GEN T1 - A NLOS-robust TOA positioning filter based on a skew-t measurement noise model AU - Nurminen, Henri AU - Ardeshiri, Tohid AU - Piche, Robert AU - Gustafsson, Fredrik PY - 2015/10/1 Y1 - 2015/10/1 N2 - A skew-t variational Bayes filter (STVBF) is applied to indoor positioning with time-of-arrival (TOA) based distance measurements and pedestrian dead reckoning (PDR). The proposed filter accommodates large positive outliers caused by occasional non-line-of-sight (NLOS) conditions by using a skew-t model of measurement errors. Real-data tests using the fusion of inertial sensors based PDR and ultra-wideband based TOA ranging show that the STVBF clearly outperforms the extended Kalman filter (EKF) in positioning accuracy with the computational complexity about three times that of the EKF. AB - A skew-t variational Bayes filter (STVBF) is applied to indoor positioning with time-of-arrival (TOA) based distance measurements and pedestrian dead reckoning (PDR). The proposed filter accommodates large positive outliers caused by occasional non-line-of-sight (NLOS) conditions by using a skew-t model of measurement errors. Real-data tests using the fusion of inertial sensors based PDR and ultra-wideband based TOA ranging show that the STVBF clearly outperforms the extended Kalman filter (EKF) in positioning accuracy with the computational complexity about three times that of the EKF. KW - Approximation methods KW - Computational modeling KW - Distance measurement KW - Gaussian distribution KW - Measurement errors KW - Noise measurement KW - Position measurement KW - NLOS KW - TOA KW - UWB KW - indoor positioning KW - robust filtering KW - skew t KW - skewness KW - variational Bayes U2 - 10.1109/IPIN.2015.7346786 DO - 10.1109/IPIN.2015.7346786 M3 - Conference contribution SN - 978-1-4673-8402-5 SP - 1 EP - 7 BT - 2015 International Conference on Indoor Positioning and Indoor Navigation (IPIN) PB - IEEE ER - TY - GEN T1 - A Notion of Positive Definiteness for Arithmetical Functions AU - Mattila, Mika AU - Haukkanen, Pentti N1 - jufoid=84299 PY - 2019 Y1 - 2019 N2 - In the theory of Fourier transform some functions are said to be positive deﬁnite based on the positive deﬁniteness property of a certain class of matrices associated with these functions. In the present article we consider how to deﬁne a similar positive deﬁniteness property for arithmetical functions, whose domain is not the set of real numbers but merely the set of positive integers. After ﬁnding a suitable deﬁnition for this concept we shall use it to construct a partial ordering on the set of arithmetical functions. We shall study some of the basic properties of our newly deﬁned relations and consider a couple of well-known arithmetical functions as examples. AB - In the theory of Fourier transform some functions are said to be positive deﬁnite based on the positive deﬁniteness property of a certain class of matrices associated with these functions. In the present article we consider how to deﬁne a similar positive deﬁniteness property for arithmetical functions, whose domain is not the set of real numbers but merely the set of positive integers. After ﬁnding a suitable deﬁnition for this concept we shall use it to construct a partial ordering on the set of arithmetical functions. We shall study some of the basic properties of our newly deﬁned relations and consider a couple of well-known arithmetical functions as examples. U2 - 10.1007/978-3-030-17519-1_5 DO - 10.1007/978-3-030-17519-1_5 M3 - Conference contribution SN - 978-3-030-17518-4 T3 - Contributions to Statistics SP - 61 EP - 74 BT - Matrices, Statistics and Big Data A2 - Ahmed, S. Ejaz A2 - Carvalho, Francisco A2 - Puntanen, Simo PB - Springer Nature ER - TY - GEN T1 - Application of Design Review to Probabilistic Risk Assessment in a Large Investment Project AU - Virtanen, Seppo AU - Penttinen, Jussi-Pekka AU - Kiiski, Mikko AU - Jokinen, Juuso N1 - Contribution: organisation=mei,FACT1=1

Portfolio EDEND: 2014-12-13 PY - 2014 Y1 - 2014 M3 - Conference contribution SP - 1 EP - 12 BT - Proceedings of the Probabilistic Safety Assessment and Management PSAM12, June 2014, Honolulu, Hawaii ER - TY - GEN T1 - Application of Hill-Clohessy-Wiltshire Equation in GNSS Orbit Prediction AU - Zhang, Xiaolong AU - Piche, Robert N1 - Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2014-10-30 PY - 2014 Y1 - 2014 U2 - 10.1109/ICL-GNSS.2014.6934162 DO - 10.1109/ICL-GNSS.2014.6934162 M3 - Conference contribution SN - 978-1-4799-5122-2 SP - 1 EP - 6 BT - Proceedings of 2014 International Conference on Localization and GNSS (ICL-GNSS), Helsinki, Finland, June 24-26, 2014 A2 - Nurmi, Jari A2 - Ruotsalainen, Laura A2 - Lohan, Elena-Simona A2 - Salcedo, Jose A2 - Thombre, Sarang PB - IEEE CY - Piscataway ER - TY - GEN T1 - Approach for Investigating Crowdfunding Campaigns with Platform Data: Case Indiegogo AU - Huhtamäki, Jukka AU - Lasrado, Lester AU - Menon, Karan AU - Kärkkäinen, Hannu AU - Jussila, Jari N1 - ORG=mat,0.5 ORG=tlo,0.5 PY - 2015 Y1 - 2015 N2 - Crowdfunding via the internet is a relatively new phenomenon in research and gaining momentum currently. While taking a data-driven approach into investigating the properties and dynamics of crowdfunding campaigns would allow the use of computational social science in investigations on crowdfunding, existing data-driven research on crowdfunding remains very limited. This is particularly true on the level of individual funder data. In this study, we contribute to the empirical body of knowledge on crowdfunding by introducing Indiegogo as a data source and, more specifically, the development and implementation of a crawler and scraper for accessing Indiegogo campaign data, and sharing this openly for other researchers. Due to the extremely dynamic and rapidly increasing amount of crowdfunding data in terms of the number of crowdfunding campaigns and the available investment and individual investor data, we believe our approach is useful for supporting public and open data-driven research, instead of providing merely a static data set. AB - Crowdfunding via the internet is a relatively new phenomenon in research and gaining momentum currently. While taking a data-driven approach into investigating the properties and dynamics of crowdfunding campaigns would allow the use of computational social science in investigations on crowdfunding, existing data-driven research on crowdfunding remains very limited. This is particularly true on the level of individual funder data. In this study, we contribute to the empirical body of knowledge on crowdfunding by introducing Indiegogo as a data source and, more specifically, the development and implementation of a crawler and scraper for accessing Indiegogo campaign data, and sharing this openly for other researchers. Due to the extremely dynamic and rapidly increasing amount of crowdfunding data in terms of the number of crowdfunding campaigns and the available investment and individual investor data, we believe our approach is useful for supporting public and open data-driven research, instead of providing merely a static data set. KW - Crowdfunding KW - Data Extraction KW - Indiegogo KW - entrepreneur KW - crawling KW - scraping KW - computational social science U2 - 10.1145/2818187.2818289 DO - 10.1145/2818187.2818289 M3 - Conference contribution SN - 978-1-4503-3948-3 BT - Academic MindTrek’15 PB - ACM ER - TY - GEN T1 - Approximation of Volume and Branch Size Distribution of Trees from Laser Scanner Data AU - Raumonen, Pasi AU - Kaasalainen, Sanna AU - Kaasalainen, Mikko AU - Kaartinen, Harri N1 - ei ut-numeroa 3.5.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution T3 - ISPRS Workshop Laser Scanning SP - 1 EP - 6 BT - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, ISPRS Workshop Laser Scanning, 2011, 29.-31.8.2011, Calgary, Canada PB - ISPRS CY - Calgary ER - TY - GEN T1 - A Reduced-Order Two-Degree-of-Freedom Composite Nonlinear Feedback Control for a Rotary DC Servo Motor AU - Pyrhönen, Veli-Pekka AU - Koivisto, Hannu AU - Vilkko, Matti PY - 2017/12/12 Y1 - 2017/12/12 N2 - We study in this paper nonlinear control of a rotary DC servo motor application. To be more specific, we design a reduced-order two-degree-of-freedom (2DOF) composite nonlinear feedback (CNF) controller for a Quanser QUBE-Servo 2 unit with a disc attachment. We compare our results with a carefully tuned proportional-derivative (PD) controller with set point weighting. Our simulation and experimental results show that the closed-loop system using 2DOF CNF controller yields much better set point tracking performance compared with the system using conventional PD-controller in terms of settling time. AB - We study in this paper nonlinear control of a rotary DC servo motor application. To be more specific, we design a reduced-order two-degree-of-freedom (2DOF) composite nonlinear feedback (CNF) controller for a Quanser QUBE-Servo 2 unit with a disc attachment. We compare our results with a carefully tuned proportional-derivative (PD) controller with set point weighting. Our simulation and experimental results show that the closed-loop system using 2DOF CNF controller yields much better set point tracking performance compared with the system using conventional PD-controller in terms of settling time. KW - Nonlinear control KW - Composite nonlinear feedback KW - motion control KW - Robust control KW - High performance control KW - Servo systems U2 - 10.1109/CDC.2017.8263951 DO - 10.1109/CDC.2017.8263951 M3 - Conference contribution SP - 2065 EP - 2071 BT - Proceedings of the 56th IEEE Conference on Decision and Control CY - Melbourne, Australia ER - TY - GEN T1 - A Simple Controller with a Reduced Order Internal Model in the Frequency Domain AU - Laakkonen, Alpo AU - Paunonen, Lassi PY - 2016 Y1 - 2016 N2 - We use frequency domain methods to study robust output regulation of a stable plant in a situation where the controller is only required to be robust with respect to a predeﬁned class of perturbations. We present a characterization for the solvability of the control problem and design a minimal order controller that achieves robustness with respect to a given class of uncertainties. The construction of the controller is illustrated with an example. AB - We use frequency domain methods to study robust output regulation of a stable plant in a situation where the controller is only required to be robust with respect to a predeﬁned class of perturbations. We present a characterization for the solvability of the control problem and design a minimal order controller that achieves robustness with respect to a given class of uncertainties. The construction of the controller is illustrated with an example. U2 - 10.1109/ECC.2016.7810583 DO - 10.1109/ECC.2016.7810583 M3 - Conference contribution SP - 1988 EP - 1992 BT - Proceedings of European Control Conference 2016 PB - IEEE ER - TY - GEN T1 - A simulator for infinite-dimensional systems with a self-tuning controller AU - Åkerblom, M. AU - Hämäläinen, T. AU - Pohjolainen, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2009 Y1 - 2009 M3 - Conference contribution SP - 5 p BT - IFAC Workshop on Control Applications of Optimization CAO'09, 6-8 May, 2009 Jyväskylä, Finland ER - TY - GEN T1 - Asteroid models from photometry and complementary data sources AU - Kaasalainen, Mikko N1 - JUFOID=50722 PY - 2016 Y1 - 2016 N2 - I discuss inversion methods for asteroid shape and spin reconstruction with photometry (lightcurves) and complementary data sources such as adaptive optics or other images, occultation timings, interferometry, and range-Doppler radar data. These are essentially different sampling modes (generalized projections) of plane-of-sky images. An important concept in this approach is the optimal weighting of the various data modes. The maximum compatibility estimate, a multimodal generalization of the maximum likelihood estimate, can be used for this purpose. I discuss the fundamental properties of lightcurve inversion by examining the two-dimensional case that, though not usable in our three-dimensional world, is simple to analyze, and it shares essentially the same uniqueness and stability properties as the 3-D case. After this, I review the main aspects of 3-D shape representations, lightcurve inversion, and the inclusion of complementary data. AB - I discuss inversion methods for asteroid shape and spin reconstruction with photometry (lightcurves) and complementary data sources such as adaptive optics or other images, occultation timings, interferometry, and range-Doppler radar data. These are essentially different sampling modes (generalized projections) of plane-of-sky images. An important concept in this approach is the optimal weighting of the various data modes. The maximum compatibility estimate, a multimodal generalization of the maximum likelihood estimate, can be used for this purpose. I discuss the fundamental properties of lightcurve inversion by examining the two-dimensional case that, though not usable in our three-dimensional world, is simple to analyze, and it shares essentially the same uniqueness and stability properties as the 3-D case. After this, I review the main aspects of 3-D shape representations, lightcurve inversion, and the inclusion of complementary data. KW - Asteroids KW - Inverse problems KW - Photometry KW - Adaptive optics KW - Interferometry KW - LIGHTCURVE INVERSION KW - OPTIMIZATION METHODS KW - SHAPE KW - RECONSTRUCTION KW - POLYHEDRON U2 - 10.1063/1.4948806 DO - 10.1063/1.4948806 M3 - Conference contribution T3 - AIP Conference Proceedings BT - Graduate School In Astronomy A2 - Chavero, C A2 - Cunha, K A2 - Carvano, J A2 - Fernandes, MB A2 - Dupke, R PB - AMER INST PHYSICS ER - TY - GEN T1 - Asymptotic Behaviour of Platoon Systems AU - Paunonen, Lassi AU - Seifert, David PY - 2016/7 Y1 - 2016/7 N2 - In this paper we study the asymptotic behaviour of various platoon-type systems using the general theory developed by the authors in a recent article. The aim is to steer an infinite number of vehicles towards a target configuration in which each vehicle has a prescribed separation from its neighbour and all vehicles are moving at a given velocity. More specifically, we study systems in which state feedback is possible, systems in which observer-based dynamic output feedback is required, and also a situation in which the control objective is modified to allow the target separations to depend on the vehicles’ velocities. We show that in the first and third cases the objective can be achieved, but that in the second case the system is unstable in the sense that the associated semigroup is not uniformly bounded. We also present some quantified results concerning the rate of convergence of the platoon to its limit state when the limit exists. AB - In this paper we study the asymptotic behaviour of various platoon-type systems using the general theory developed by the authors in a recent article. The aim is to steer an infinite number of vehicles towards a target configuration in which each vehicle has a prescribed separation from its neighbour and all vehicles are moving at a given velocity. More specifically, we study systems in which state feedback is possible, systems in which observer-based dynamic output feedback is required, and also a situation in which the control objective is modified to allow the target separations to depend on the vehicles’ velocities. We show that in the first and third cases the objective can be achieved, but that in the second case the system is unstable in the sense that the associated semigroup is not uniformly bounded. We also present some quantified results concerning the rate of convergence of the platoon to its limit state when the limit exists. KW - Vehicle platoon KW - ordinary differential equations KW - asymptotic behaviour KW - state feedback KW - rates of convergence M3 - Conference contribution SP - 830 EP - 836 BT - Proceedings of the 22nd International Symposium on Mathematical Theory of Networks and Systems PB - University of Minnesota ER - TY - GEN T1 - Axiomatic Extensions of Höhle's Monoidal Logic AU - Turunen, Esko N1 - Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution SN - 978-90-7877-00-0 T3 - Conference of the European Society for Fuzzy Logic and Technology EUSFLAT-LFA SP - 163 EP - 168 BT - Proceedings of the 7th conference of the European Society for Fuzzy Logic and Technology EUSFLAT-LFA 2011, Aix-Les-Bains, France, 18 - 22 July 2011 PB - Atlantis Press CY - Amsterdam ER - TY - GEN T1 - Bandwidth and Storage Reduction of Radio Maps for Offline WLAN Positioning AU - Wirola, Laura AU - Wirola, Lauri AU - Piche, Robert N1 - to appear in IEEEXPLORE

Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2013-11-29

Publisher name: IEEE PY - 2013 Y1 - 2013 N2 - Most of the existing mobile device positioning methods require data connectivity, i.e. they work in the mobile-assisted, or online mode. However, this consumes energy, induces transmission costs and results in unnecessarily long time-to-first-fix. These issues can be alleviated using mobile-based, or offline, mode. In this mode the device carries a subset of the global radio map in memory for fast positioning without data connection. The challenge of this approach is the large size of the offline radio map that needs to be downloaded, stored and updated periodically in the mobile device. This paper presents a method to find the significant APs in the global radio map and proposes using only those in offline positioning in order to compress the size of the required offline radio map. We also propose a method to further compress the size of the offline radio map by hashing the globally unique AP BSSIDs into locally unique shortened BSSIDs. We test the proposed methods with real-world data. AB - Most of the existing mobile device positioning methods require data connectivity, i.e. they work in the mobile-assisted, or online mode. However, this consumes energy, induces transmission costs and results in unnecessarily long time-to-first-fix. These issues can be alleviated using mobile-based, or offline, mode. In this mode the device carries a subset of the global radio map in memory for fast positioning without data connection. The challenge of this approach is the large size of the offline radio map that needs to be downloaded, stored and updated periodically in the mobile device. This paper presents a method to find the significant APs in the global radio map and proposes using only those in offline positioning in order to compress the size of the required offline radio map. We also propose a method to further compress the size of the offline radio map by hashing the globally unique AP BSSIDs into locally unique shortened BSSIDs. We test the proposed methods with real-world data. M3 - Conference contribution T3 - International Conference on Indoor Positioning and Indoor Navigation SP - 665 EP - 673 BT - International Conference on Indoor Positioning and Indoor Navigation, IPIN 2013, 28-31 Oct 2013, Montbéliard-Belfort, France PB - IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Bayesian assaying of GUHA nuggets AU - Piche, Robert AU - Turunen, Esko N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1007/978-3-642-14055-6_36 DO - 10.1007/978-3-642-14055-6_36 M3 - Conference contribution SN - 978-3-642-14054-9 SP - 348 EP - 355 BT - Information Processing and Management of Uncertainty in Knowledge-Based Systems. Theory and Methods, 13th International Conference, IPMU 2010, Dortmund, Germany, June 28 - July 2, 2010. Communications in Computer and Information Science A2 - Hüllermeier, Eyke A2 - Kruse, Rudolf A2 - Hoffmann, Frank ER - TY - GEN T1 - Bayesian Methods for Hybrid Indoor Positioning AU - Nurminen, Henri N1 - siirretään 2015

Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2015-01-14 xabstract PY - 2014 Y1 - 2014 M3 - Conference contribution BT - IPIN 2014 - 5th International Conference on Indoor Positioning and Indoor Navigation, 27th - 30 th October, 2014, Busan, South Korea ER - TY - GEN T1 - Bayes trees and forests: combining precise empirical and theoretical tree models AU - Kaasalainen, Mikko AU - Potapov, Ilya AU - Raumonen, Pasi AU - Åkerblom, Markku AU - Sievänen, Risto AU - Kaasalainen, Sanna N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: Finnish Society of Forest Science; Finnish Forest Research Institute; University of Helsinki PY - 2013 Y1 - 2013 M3 - Conference contribution SN - 978-951-651-408-9 T3 - International Conference on Functional-Structural Plant Models SP - 61 EP - 63 BT - 7th International Conference on Functional-Structural Plant Models, FSPM2013, FSPM2013, 9.-14.6.2013, Saariselkä, Finland A2 - Sievänen, R. A2 - Nikinmaa, E. A2 - Godin, C. A2 - Lintunen, A. A2 - Nygren, P. PB - Finnish Society of Forest Science; Finnish Forest Research Institute; University of Helsinki CY - Vantaa ER - TY - GEN T1 - Business Angels and Investment Organizations as Networked Co-creators of the Finnish Innovation Ecosystem AU - Huhtamäki, Jukka AU - Russell, Martha G. AU - Still, K. AU - Rubens, Neil AU - Yu, Jiafeng (Camilla) N1 - ei ut-numeroa 8.3.2014

Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution T3 - Triple Helix International Conference SP - 1 EP - 15 BT - Proceedings of the Triple Helix IX International Conference: Silicon Valley: Global Model or Unique Anomaly? 11-14 July, 2011, Stanford, California, USA PB - Stanford University, H-STAR Institute Center for Innovation and Communication CY - Stanford, CA ER - TY - GEN T1 - Challenges in Heterogeneous Web Data Analytics - Case Finnish Growth Companies in Social Media AU - Salonen, Jaakko AU - Huhtamäki, Jukka AU - Nykänen, Ossi N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: ACM PY - 2013 Y1 - 2013 N2 - Diverse data about various phenomena are implicitly available in the modern web. In particular websites categorized as social media provide rich and heterogeneous data about various entities such as people, corporations, brands as well as their properties and relationships. An analyst who seeks to leverage this diverse data is faced with the challenge of integrating and making sense of a set of heterogeneous data sources. In this paper, we provide an introduction and a problem statement for heterogeneous web data analytics. To further highlight and discuss practical challenges, we introduce a case study of Finnish growth companies in social media. Instead of a purely data-driven approach, the presented approach is rooted in the idea that an analyst can actively participate in the data collection and integration process, while the process can still retain repeatability and transparency. The key contribution of this paper is the statement of the challenges related to heterogeneous web data analytics. AB - Diverse data about various phenomena are implicitly available in the modern web. In particular websites categorized as social media provide rich and heterogeneous data about various entities such as people, corporations, brands as well as their properties and relationships. An analyst who seeks to leverage this diverse data is faced with the challenge of integrating and making sense of a set of heterogeneous data sources. In this paper, we provide an introduction and a problem statement for heterogeneous web data analytics. To further highlight and discuss practical challenges, we introduce a case study of Finnish growth companies in social media. Instead of a purely data-driven approach, the presented approach is rooted in the idea that an analyst can actively participate in the data collection and integration process, while the process can still retain repeatability and transparency. The key contribution of this paper is the statement of the challenges related to heterogeneous web data analytics. U2 - 10.1145/2523429.2523481 DO - 10.1145/2523429.2523481 M3 - Conference contribution SN - 978-1-4503-1992-8 T3 - MindTrek Conference SP - 131 EP - 138 BT - 17th International Academic MindTrek Conference, October 1-4, 2013, Tampere, Finland PB - ACM ER - TY - GEN T1 - Closed-form algorithms in mobile positioning: Myths and misconceptions AU - Sirola, Niilo N1 - poistettu tupla r=3045, esitelmä http://math.tut.fi/posgroup/sirola-wpnc2010-slides.ppt

Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1109/WPNC.2010.5653789 DO - 10.1109/WPNC.2010.5653789 M3 - Conference contribution SN - 978-1-4244-7157-7 SP - 38 EP - 44 BT - Proceedings of the 7th Workshop on Positioning, Navigation and Communication 2010 WPNC'10, 11-12 March 2010, Dresden, Germany ER - TY - GEN T1 - Comparing two stochastic differential equation models for protein kinase C activation pathway AU - Intosalmi, Jukka AU - Manninen, Tiina AU - Ruohonen, Keijo AU - Linne, Marja-Leena N1 - Yhteisjulkaisu MAT kanssa

Contribution: organisation=sgn,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5 PY - 2010 Y1 - 2010 M3 - Conference contribution SP - 139 BT - Abstracts of Papers, Posters and Talks presented at the 2010 Joint RECOMB Satellite Conference on Systems Biology - Regulatory Genomics - DREAM5, New York, USA, 16-20 November 2010 ER - TY - GEN T1 - Competence advancement supported by social media AU - Väljataga, T. AU - Fielder, S. N1 - Contribution: organisation=mat,FACT1=1 PY - 2008 Y1 - 2008 M3 - Conference contribution SP - 54 EP - 66 BT - Proceedings of the TEN Competence Special Technology Track on Technology Support for Self-Organised Learners CY - Salzburg ER - TY - GEN T1 - Composite Nonlinear Feedback Control of a Chemical Reactor AU - Pyrhönen, Veli-Pekka AU - Koivisto, Hannu PY - 2015/3/18 Y1 - 2015/3/18 N2 - This paper studies the application of composite nonlinear feedback (CNF) control for a continuous time stirred tank reactor. Inside the reactor, an exothermic chemical reaction occurs, which requires cooling when concentration is commanded from low to high conversion rate to prevent a thermal runaway. A full-state CNF controller is designed for adjusting the temperature of the cooling jacket using concentration and temperature measurements. A continuous time gain-scheduled cascade controller, as well as a model predictive controller (MPC) is also fabricated for comparison. The gain-scheduled cascade controller has a proportional-integral (PI) controller as a primary loop controller, and a P-controller as a secondary loop controller. The simulation results show that the CNF controller is able to offer the best overall tracking performance as measured by the integral-of-absolute-error (IAE) criterion. In addition, the CNF controller does not need gain-scheduling for tuning purposes; the CNF controller is capable of changing its tuning as a function of control error only. AB - This paper studies the application of composite nonlinear feedback (CNF) control for a continuous time stirred tank reactor. Inside the reactor, an exothermic chemical reaction occurs, which requires cooling when concentration is commanded from low to high conversion rate to prevent a thermal runaway. A full-state CNF controller is designed for adjusting the temperature of the cooling jacket using concentration and temperature measurements. A continuous time gain-scheduled cascade controller, as well as a model predictive controller (MPC) is also fabricated for comparison. The gain-scheduled cascade controller has a proportional-integral (PI) controller as a primary loop controller, and a P-controller as a secondary loop controller. The simulation results show that the CNF controller is able to offer the best overall tracking performance as measured by the integral-of-absolute-error (IAE) criterion. In addition, the CNF controller does not need gain-scheduling for tuning purposes; the CNF controller is capable of changing its tuning as a function of control error only. KW - exothermic reaction KW - nonlinear control KW - nonlinear dynamics KW - cascade control M3 - Conference contribution T3 - SAS julkaisusarja BT - Proceedings of AutomaatioXXI, The Industrial Revolution of Internet – From Intelligent Devices to Networked Intelligence PB - Suomen Automaatioseura ry CY - Helsinki, Finland ER - TY - GEN T1 - Comprehensive Quantitative Tree Models from TLS Data AU - Åkerblom, Markku AU - Raumonen, Pasi AU - Kaasalainen, Mikko AU - Kaasalainen, Sanna AU - Kaartinen, Harri N1 - Poistettu tupla r=3140

Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Electrical and Electronics Engineers IEEE PY - 2012 Y1 - 2012 U2 - 10.1109/IGARSS.2012.6352751 DO - 10.1109/IGARSS.2012.6352751 M3 - Conference contribution SN - 978-1-4673-1160-1 T3 - IEEE International Geoscience and Remote Sensing Symposium SP - 6507 EP - 6510 BT - IEEE International Geoscience and Remote Sensing Symposium, IGARSS, 2012, 22.-27.7.2012, Munich, Germany PB - Institute of Electrical and Electronics Engineers IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Computational Model for Simulating Multifocal Imaging in Optical Projection Tomography AU - Koskela, Olli AU - Belay, Birhanu AU - Pursiainen, Sampsa AU - Figueiras, Edite AU - Hyttinen, Jari PY - 2017 Y1 - 2017 N2 - We present a computational model describing the blurring of particles with respect to focal distance in 3D optical imaging. The model can be used to improve reconstructions in optical projection tomography. AB - We present a computational model describing the blurring of particles with respect to focal distance in 3D optical imaging. The model can be used to improve reconstructions in optical projection tomography. U2 - 10.1364/MATH.2017.MTu1C.3 DO - 10.1364/MATH.2017.MTu1C.3 M3 - Conference contribution BT - Mathematics in Imaging 2017 PB - Optical Society of America ER - TY - GEN T1 - Context-Driven Social Network Visualisation: Case Wiki Co-Creation AU - Huhtamäki, Jukka AU - Salonen, Jaakko AU - Marttila, Jarno AU - Nykänen, Ossi N1 - Contribution: organisation=mat hyplab,FACT1=1 PY - 2010 Y1 - 2010 N2 - Along social media and Web 2.0, the amount of data sources potentially available for social network visualisation has snowballed. Recent development on information visualisation technologies contribute to the availability of tools enabling visualisation of social media data. Yet, applying the tools in diff erent usage contexts is often diffcult. The data formats vary and many of the tools are platform-specific. Potential tools each have their strengths but often a single tool is not suffcient for covering all the aspects of analysis. In this paper, we describe the means of applying component-based information visualisation to streamline social network visualisation. Further, through our approach, we seek to narrow the gap between everyday knowledge work and visual social network analysis of the data that knowledge workers process. We acknowledge the need of programming skills in introducing the visualisations to different usage contexts but yet we see that teams of analysts can apply the approach when conducting network analysis in varying contexts. The main contributions of this article are the following: a description and an analysis of a streamlined social network visual analysis process and a brief review of the related applications and tools, based on the idea of conceptual integration of visual social network analysis and augmented browsing. AB - Along social media and Web 2.0, the amount of data sources potentially available for social network visualisation has snowballed. Recent development on information visualisation technologies contribute to the availability of tools enabling visualisation of social media data. Yet, applying the tools in diff erent usage contexts is often diffcult. The data formats vary and many of the tools are platform-specific. Potential tools each have their strengths but often a single tool is not suffcient for covering all the aspects of analysis. In this paper, we describe the means of applying component-based information visualisation to streamline social network visualisation. Further, through our approach, we seek to narrow the gap between everyday knowledge work and visual social network analysis of the data that knowledge workers process. We acknowledge the need of programming skills in introducing the visualisations to different usage contexts but yet we see that teams of analysts can apply the approach when conducting network analysis in varying contexts. The main contributions of this article are the following: a description and an analysis of a streamlined social network visual analysis process and a brief review of the related applications and tools, based on the idea of conceptual integration of visual social network analysis and augmented browsing. M3 - Conference contribution SP - 1 EP - 13 BT - Proceedings of the Knowledge Federation 2010: Self-Organizing Collective Mind, October 3-6, 2010, Dubrovnik, Croatia A2 - Karabeg, Dino A2 - Park, Jack ER - TY - GEN T1 - Cubature-based Kalman filters for positioning AU - Pesonen, Henri AU - Piche, Robert N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1109/WPNC.2010.5653829 DO - 10.1109/WPNC.2010.5653829 M3 - Conference contribution SN - 978-1-4244-7157-7 SP - 45 EP - 49 BT - Proceedings of the 7th Workshop on Positioning, Navigation and Communication 2010 WPNC'10, 11-12 March 2010, Dresden, Germany ER - TY - GEN T1 - Datamap Visualization Technique for Interactively Visualizing Large Datasets AU - Nykänen, Ossi N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: ACM PY - 2013 Y1 - 2013 U2 - 10.1145/2523429.2523458 DO - 10.1145/2523429.2523458 M3 - Conference contribution SN - 978-1-4503-1992-8 T3 - MindTrek Conference SP - 52 EP - 58 BT - 17th International Academic MindTrek Conference, October 1-4, 2013, Tampere, Finland A2 - Lugmayr, Artur A2 - Franssila, Heljä A2 - Kärkkäinen, Hannu A2 - Paavilainen, Janne PB - ACM ER - TY - GEN T1 - Developing Learning and Teaching in Engineering Mathematics with and without Technology AU - Joutsenlahti, Jorma AU - Ali-Löytty, Simo AU - Pohjolainen, Seppo PY - 2016/9/15 Y1 - 2016/9/15 N2 - University teachers of mathematics have begun to observe that nowadays new students when beginning their studies do not have as good a mathematical proficiency as before. The phenomenon has been noticed in all western countries during recent decades [1, 2]. What shall we do? We think that there are at least two available courses of action for improved learning results in university mathematics: 1) to identify as soon as possible the students who have an insufficient knowledge base in mathematics, and to begin remedial instruction for them, and 2) to develop mathematics learning environments both with and without technology.The aim of this paper is to describe how Tampere University of Technology (TUT) has developed learning environments in mathematics during the last decade. We focus in the paper on two cases: 1) a multisemiotic approach to mathematical concepts and procedures, and 2) computer aided assessment and learning systems.The first case consists of developing studies in mathematical exercises in which new kinds of problem-solving have been constructed. In the second case new students have participated in an ICT –based basic skills test at the beginning of their mathematics studies, to enable them to practice mathematical procedures in solving processes [3]. Electronic and web-based tools make it possible for students to learn independently at any time, and for teachers, offer an effective way to evaluate students’ proficiency. AB - University teachers of mathematics have begun to observe that nowadays new students when beginning their studies do not have as good a mathematical proficiency as before. The phenomenon has been noticed in all western countries during recent decades [1, 2]. What shall we do? We think that there are at least two available courses of action for improved learning results in university mathematics: 1) to identify as soon as possible the students who have an insufficient knowledge base in mathematics, and to begin remedial instruction for them, and 2) to develop mathematics learning environments both with and without technology.The aim of this paper is to describe how Tampere University of Technology (TUT) has developed learning environments in mathematics during the last decade. We focus in the paper on two cases: 1) a multisemiotic approach to mathematical concepts and procedures, and 2) computer aided assessment and learning systems.The first case consists of developing studies in mathematical exercises in which new kinds of problem-solving have been constructed. In the second case new students have participated in an ICT –based basic skills test at the beginning of their mathematics studies, to enable them to practice mathematical procedures in solving processes [3]. Electronic and web-based tools make it possible for students to learn independently at any time, and for teachers, offer an effective way to evaluate students’ proficiency. M3 - Conference contribution BT - SEFI 2016 Annual Conference Proceedings PB - European Society for Engineering Education SEFI ER - TY - GEN T1 - Dual Look at Robust Regulation: Frequency Domain and State Space Approaches AU - Laakkonen, Petteri AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Electrical and Electronics Engineers IEEE PY - 2012 Y1 - 2012 U2 - 10.1109/MMAR.2012.6347929 DO - 10.1109/MMAR.2012.6347929 M3 - Conference contribution SN - 978-1-4673-2121-1 T3 - International Conference on Methods and Models in Automation & Robotics SP - 136 EP - 141 BT - Proceedings of MMAR 2012. 17th International Conference on Methods and Models in Automation & Robotics, MMAR 2012, 27-30 August 2012, Miedzyzdroje, Poland PB - Institute of Electrical and Electronics Engineers IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Engineering motif search for large graphs AU - Björklund, Andreas AU - Kaski, Petteri AU - Kowalik, Łukasz AU - Lauri, Juho PY - 2015 Y1 - 2015 N2 - In the graph motif problem, we are given as input a vertexcolored graph H (the host graph) and a multiset of colors M (the motif). Our task is to decide whether H has a connected set of vertices whose multiset of colors agrees with M. The graph motif problem is NP-complete but known to admit parameterized algorithms that run in linear time in the size of H. We demonstrate that algorithms based on constrained multilinear sieving are viable in practice, scaling to graphs with hundreds of millions of edges as long as M remains small. Furthermore, our implementation is topologyinvariant relative to the host graph H, meaning only the most crude graph parameters (number of edges and number of vertices) suffice in practice to determine the algorithm performance. AB - In the graph motif problem, we are given as input a vertexcolored graph H (the host graph) and a multiset of colors M (the motif). Our task is to decide whether H has a connected set of vertices whose multiset of colors agrees with M. The graph motif problem is NP-complete but known to admit parameterized algorithms that run in linear time in the size of H. We demonstrate that algorithms based on constrained multilinear sieving are viable in practice, scaling to graphs with hundreds of millions of edges as long as M remains small. Furthermore, our implementation is topologyinvariant relative to the host graph H, meaning only the most crude graph parameters (number of edges and number of vertices) suffice in practice to determine the algorithm performance. UR - http://www.scopus.com/inward/record.url?scp=84937777832&partnerID=8YFLogxK U2 - 10.1137/1.9781611973754.10 DO - 10.1137/1.9781611973754.10 M3 - Conference contribution T3 - Workshop on Algorithm Engineering and Experiments SP - 104 EP - 118 BT - 2015 Proceedings of the Seventeenth Workshop on Algorithm Engineering and Experiments (ALENEX) ER - TY - GEN T1 - Estimating Above Ground Biomass from Terrestrial Laser Scanning in Autralian Eucalypt Open Forest AU - Calders, Kim AU - Newnham, Glenn AU - Herold, Martin AU - Murphy, Simon AU - Culvenor, Darius AU - Raumonen, Pasi AU - Burt, Andrew AU - Armston, John AU - Avitabile, Valerio AU - Disney, Mathias N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: Silvilaser Beijing 2013 PY - 2013 Y1 - 2013 M3 - Conference contribution T3 - International Conference on LiDAR Applications for Assessing Forest Ecosystems SP - 1 EP - 7 BT - 13th International Conference on LiDAR Applications for Assessing Forest Ecosystems, SilviLaser 2013, 9.-11.10.2013. Beijing, China PB - Silvilaser Beijing 2013 CY - Beijing, China ER - TY - GEN T1 - Estimation of base station position using timing advance measurements AU - Raitoharju, Matti AU - Ali-Löytty, Simo AU - Wirola, Lauri N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Conference contribution SN - 978-1-4244-9103-2 SP - 182 EP - 186 BT - 2010 International Conference on Signal and Information Processing ICSIP 2010, Changsha, China, 15.12.2010 ER - TY - GEN T1 - Estimation of initial state and model parameters for autonomous GNSS orbit prediction AU - Ala-Luhtala, Juha AU - Seppänen, Mari AU - Ali-Löytty, Simo AU - Piche, Robert AU - Nurminen, Henri N1 - Book of Abstracts: http://issuu.com/robhen7979/docs/2013bookofabstracts.doc

Contribution: organisation=mat,FACT1=0.5

Contribution: organisation=ase,FACT2=0.5

Portfolio EDEND: 2013-07-29

Publisher name: IGNSS Society PY - 2013 Y1 - 2013 N2 - In self-assisted GNSS the orbit of a satellite is predicted by solving the differential equation that models its motion. Our motion model includes the most important forces: Earth's gravity, lunar and solar gravity and solar radiation pressure. Unmodeled forces are taken into account by using Gaussian white noise term with covariance matrix estimated offline from historical orbital data. The estimation of model parameters (solar radiation pressure and Earth orientation parameters) and initial state for the prediction includes both offline and online stages. In the offline stage, priors for the solar radiation pressure parameters are estimated using precise orbits issued by the International GNSS service (IGS). In the online stage, the satellite’s broadcast ephemeris is used to estimate the initial state and model parameters. The estimation of the initial state is formulated as non-linear continuous-time filtering problem with discrete-time measurements. The filtering equations are solved numerically and the performance of different numerical methods (Extended, Cubature and Unscented Kalman filters) is compared. Using the estimated initial state and model parameters, the satellite orbits are predicted 5 days into the future. The accuracy and consistency of the predicted orbits is analysed by comparing with the IGS precise ephemerides. In this paper only GPS satellites are considered, but the method can be extended to other satellite systems. AB - In self-assisted GNSS the orbit of a satellite is predicted by solving the differential equation that models its motion. Our motion model includes the most important forces: Earth's gravity, lunar and solar gravity and solar radiation pressure. Unmodeled forces are taken into account by using Gaussian white noise term with covariance matrix estimated offline from historical orbital data. The estimation of model parameters (solar radiation pressure and Earth orientation parameters) and initial state for the prediction includes both offline and online stages. In the offline stage, priors for the solar radiation pressure parameters are estimated using precise orbits issued by the International GNSS service (IGS). In the online stage, the satellite’s broadcast ephemeris is used to estimate the initial state and model parameters. The estimation of the initial state is formulated as non-linear continuous-time filtering problem with discrete-time measurements. The filtering equations are solved numerically and the performance of different numerical methods (Extended, Cubature and Unscented Kalman filters) is compared. Using the estimated initial state and model parameters, the satellite orbits are predicted 5 days into the future. The accuracy and consistency of the predicted orbits is analysed by comparing with the IGS precise ephemerides. In this paper only GPS satellites are considered, but the method can be extended to other satellite systems. M3 - Conference contribution SP - 1 EP - 15 BT - International Global Navigation Satellite Systems Society IGNSS Symposium 2013, 16-18 July, 2013, Gold Coast, Queensland, Australia PB - IGNSS Society CY - Tweed Heads, NSW, Australia ER - TY - GEN T1 - Evaluating the Consistency of Estimation AU - Ivanov, Pavel AU - Ali-Löytty, Simo AU - Piche, Robert N1 - Contribution: organisation=ase,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Portfolio EDEND: 2014-11-25 PY - 2014 Y1 - 2014 U2 - 10.1109/ICL-GNSS.2014.6934171 DO - 10.1109/ICL-GNSS.2014.6934171 M3 - Conference contribution SN - 978-1-4799-5122-2 BT - Proceedings of 2014 International Conference on Localization and GNSS (ICL-GNSS), Helsinki, Finland, June 24-26, 2014 PB - IEEE CY - Piscataway ER - TY - GEN T1 - Experienced risks in social media use – longitudinal study among university students AU - Jussila, Jari AU - Aramo-Immonen, Heli PY - 2016/7/4 Y1 - 2016/7/4 N2 - Several recent studies indicate that there is a need for increased use of ICT and social media in the Finnish education [1], [2]. This research was conducted in order to explore the attitude towards social media use among university students. The motivation for seeking answer to the research question: “What risks students experience in social media use?” derived from the need to discover learning barriers in social media based learning environments. In particular, there is a need for novel interaction means in order to co-create and learn informally [3] also beyond the traditional classroom. The assumptions, beliefs and attitudes towards social media are studied from the perspective of perceived risks of the students. The study was conducted among graduate students attending “Communities and Social Media in Knowledge Management” course between the years 2012-2016. A web-based survey was executed annually, with a total of 113 respondents. Based on the results we were able to categorize the perceived risks and derive implications on how to lower learning barriers of students in social media based learning environments. AB - Several recent studies indicate that there is a need for increased use of ICT and social media in the Finnish education [1], [2]. This research was conducted in order to explore the attitude towards social media use among university students. The motivation for seeking answer to the research question: “What risks students experience in social media use?” derived from the need to discover learning barriers in social media based learning environments. In particular, there is a need for novel interaction means in order to co-create and learn informally [3] also beyond the traditional classroom. The assumptions, beliefs and attitudes towards social media are studied from the perspective of perceived risks of the students. The study was conducted among graduate students attending “Communities and Social Media in Knowledge Management” course between the years 2012-2016. A web-based survey was executed annually, with a total of 113 respondents. Based on the results we were able to categorize the perceived risks and derive implications on how to lower learning barriers of students in social media based learning environments. KW - social media KW - social media risks KW - e-communication KW - knowledge management UR - https://iated.org/edulearn/ U2 - 10.21125/edulearn.2016.1257 DO - 10.21125/edulearn.2016.1257 M3 - Conference contribution VL - 8 T3 - EDULEARN Proceedings SP - 1255 EP - 1260 BT - EDULEARN16 Proceedings A2 - Gómez Chova, L A2 - López Martínez, A A2 - Candel Torres, I PB - IATED Academy ER - TY - GEN T1 - Explaining innovation with indicators of mobility and networks: Insights into central innovation nodes in Europe AU - Still, Kaisa AU - Russell, Martha G. AU - Huhtamäki, Jukka AU - Turpeinen, Marko AU - Rubens, Neil N1 - ei ut-numeroa 17.5.2014

Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution T3 - Triple Helix International Conference SP - 1 EP - 17 BT - Proceedings of the Triple Helix IX International Conference: Silicon Valley: Global Model or Unique Anomaly? 11-14 July, 2011, Stanford, California, USA PB - Stanford University, H-STAR Institute Center for Innovation and Communication CY - Stanford, CA ER - TY - GEN T1 - Facilitating active participation in web-based co-development AU - Friedrich, Pirjo AU - Huhtamäki, Jukka AU - Koskela-Huotari, Kaisa AU - Karppinen, Kaarina AU - Still, Kaisa N1 - ei ut-numeroa 12.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Akademika forlag PY - 2012 Y1 - 2012 M3 - Conference contribution SN - 978-82-321-0088-0 T3 - Innovation Through Social Media SP - 16 EP - 23 BT - Proceedings of Innovation through Social Media, ISM 2012 workshop proceedings, December 3, 2012, Oslo, Norway PB - AKADEMIKA FORLAG CY - Trondheim, Norway ER - TY - GEN T1 - Fast Automatic Method for Constructing Topologically and Geometrically Precise Tree Models from TLS Data AU - Raumonen, Pasi AU - Casella, Eric AU - Disney, Mathias AU - Åkerblom, Markku AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-07-29

Publisher name: Finnish Society of Forest Science; Finnish Forest Research Institute; University of Helsinki PY - 2013 Y1 - 2013 M3 - Conference contribution SN - 978-951-651-408-9 T3 - International Conference on Functional-Structural Plant Models SP - 89 EP - 91 BT - 7th International Conference on Functional-Structural Plant Models, FSPM2013, 9.-14.6.2013, Saariselkä, Finland A2 - Sievänen, R. A2 - Nikinmaa, E. A2 - Godin, C. A2 - Lintunen, A. A2 - Nygren, P. PB - Finnish Society of Forest Science; Finnish Forest Research Institute; University of Helsinki CY - Vantaa ER - TY - GEN T1 - Fast fourier color constancy and grayness index for ISPA illumination estimation challenge AU - Qian, Yanlin AU - Chen, Ke AU - Yu, Huanglin N1 - EXT="Chen, Ke" PY - 2019/10/17 Y1 - 2019/10/17 N2 - We briefly introduce two submissions to the Illumination Estimation Challenge, in the Int'l Workshop on Color Vision, affiliated to the 11th Int'l Symposium on Image and Signal Processing and Analysis. The fourier-transform-based submission is ranked 3rd, and the statistical Gray-pixel-based one ranked 6th. AB - We briefly introduce two submissions to the Illumination Estimation Challenge, in the Int'l Workshop on Color Vision, affiliated to the 11th Int'l Symposium on Image and Signal Processing and Analysis. The fourier-transform-based submission is ranked 3rd, and the statistical Gray-pixel-based one ranked 6th. KW - Color constancy KW - FFCC KW - Gray pixel KW - Illumination U2 - 10.1109/ISPA.2019.8868451 DO - 10.1109/ISPA.2019.8868451 M3 - Conference contribution T3 - International Symposium on Image and Signal Processing and Analysis, ISPA SP - 352 EP - 354 BT - ISPA 2019 - 11th International Symposium on Image and Signal Processing and Analysis A2 - Loncaric, Sven A2 - Bregovic, Robert A2 - Carli, Marco A2 - Subasic, Marko PB - IEEE ER - TY - GEN T1 - Feedforward Output Regulation for Distributed Parameter Systems with Infinite-Dimensional Exosystems AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - ei ut-numeroa 27.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: IEEE PY - 2012 Y1 - 2012 U2 - 10.1109/CDC.2012.6426567 DO - 10.1109/CDC.2012.6426567 M3 - Conference contribution SN - 978-1-4673-2065-8 T3 - IEEE Conference on Decision and Control SP - 1566 EP - 1571 BT - Proceedings of the 51st IEEE Conference on Decision and Control, IEEE CDC 2012, December 10-13 2012, Maui, Hawaii, USA PB - IEEE CY - Piscataway, NJ ER - TY - GEN T1 - FiB T2 - Squeezing loop invariants by interpolation between forward/backward predicate transformers AU - Lin, Shang-Wei AU - Sun, Jun AU - Xiao, Hao AU - Liu, Yang AU - Sanán, David AU - Hansen, Henri PY - 2017/10 Y1 - 2017/10 N2 - Loop invariant generation is a fundamental problem in program analysis and verification. In this work, we propose a new approach to automatically constructing inductive loop invariants. The key idea is to aggressively squeeze an inductive invariant based on Craig interpolants between forward and backward reachability analysis. We have evaluated our approach by a set of loop benchmarks, and experimental results show that our approach is promising. AB - Loop invariant generation is a fundamental problem in program analysis and verification. In this work, we propose a new approach to automatically constructing inductive loop invariants. The key idea is to aggressively squeeze an inductive invariant based on Craig interpolants between forward and backward reachability analysis. We have evaluated our approach by a set of loop benchmarks, and experimental results show that our approach is promising. U2 - 10.1109/ASE.2017.8115690 DO - 10.1109/ASE.2017.8115690 M3 - Conference contribution T3 - IEEE/ACM International Conference on Automated Software Engineering SP - 793 EP - 803 BT - Proceedings of the 32nd IEEE/ACM International Conference on Automated Software Engineering A2 - Rosu, Grigore A2 - Di Penta, Massimiliano A2 - Nguyen, Tien N. PB - IEEE Press ER - TY - GEN T1 - Gaussian mixture filter allowing negative weights and its application to positioning using signal strength measurements AU - Muller, Philipp AU - Ali-Löytty, Simo AU - Dashti, Marzieh AU - Nurminen, Henri AU - Piche, Robert N1 - ei ut-numeroa 22.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Electrical and Electronics Engineers IEEE PY - 2012 Y1 - 2012 N2 - This paper proposes a novel Gaussian Mixture Filter (GMF) that allows components with negative weights. In case of a ring-shaped likelihood function, the new filter keeps the number of components low by approximating the likelihood as a Gaussian mixture (GM) of two components, one with positive and the other with negative weight. In this article, the filter is applied to positioning with received signal strength (RSS) based range measurements. The filter is tested using simulated measurements, and the tests indicate that the new GMF outperforms the Extended Kalman Filter (EKF) in both accuracy and consistency. AB - This paper proposes a novel Gaussian Mixture Filter (GMF) that allows components with negative weights. In case of a ring-shaped likelihood function, the new filter keeps the number of components low by approximating the likelihood as a Gaussian mixture (GM) of two components, one with positive and the other with negative weight. In this article, the filter is applied to positioning with received signal strength (RSS) based range measurements. The filter is tested using simulated measurements, and the tests indicate that the new GMF outperforms the Extended Kalman Filter (EKF) in both accuracy and consistency. U2 - 10.1109/WPNC.2012.6268741 DO - 10.1109/WPNC.2012.6268741 M3 - Conference contribution SN - 978-1-4673-1437-4 T3 - Workshop on Positioning, Navigation and Communication SP - 71 EP - 76 BT - Proceedings of WPNC 2012, 9th Workshop on Positioning, Navigation and Communication, March 15-16, 2012, Dresden, Germany PB - Institute of Electrical and Electronics Engineers IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Gender and Innovation: Networks of Executive Women in Technology-Based Companies AU - Still, Kaisa AU - Russell, Martha G. AU - Huhtamäki, Jukka AU - Yu, Jiafeng (Camilla) AU - Rubens, Neil N1 - ei ut-numeroa 17.5.2014

Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution T3 - Triple Helix International Conference SP - 1 EP - 20 BT - Proceedings of the Triple Helix IX International Conference: Silicon Valley: Global Model or Unique Anomaly? 11-14 July, 2011, Stanford, California, USA PB - Stanford University, H-STAR Institute Center for Innovation and Communication CY - Stanford, CA ER - TY - GEN T1 - Generalized hyperbolic harmonic functions in the plane AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki AU - Vuojamo, Vesa PY - 2015/3/10 Y1 - 2015/3/10 N2 - We consider solutions of the equation yΔh (x,y)-k ah/ay=0 in the plane. These functions already have been investigated by Weinstein around 1950 in connection of generalized axially symmetric potential theory. We have found several results concerning these type of functions, called k-hyperbolic harmonic functions, in higher dimensions. In this paper, we show in the plane case that it is possible to compute the explicit fundamental solutions in terms of the hyperbolic metric. These results may be used to find fundamental solutions in all even dimensional spaces. The key tools are the transformation properties of hyperbolic metric of the Poincaré upper half space model. AB - We consider solutions of the equation yΔh (x,y)-k ah/ay=0 in the plane. These functions already have been investigated by Weinstein around 1950 in connection of generalized axially symmetric potential theory. We have found several results concerning these type of functions, called k-hyperbolic harmonic functions, in higher dimensions. In this paper, we show in the plane case that it is possible to compute the explicit fundamental solutions in terms of the hyperbolic metric. These results may be used to find fundamental solutions in all even dimensional spaces. The key tools are the transformation properties of hyperbolic metric of the Poincaré upper half space model. KW - axially symmetric KW - fundamental solution KW - Hyperbolic KW - Laplace-Beltrami U2 - 10.1063/1.4912658 DO - 10.1063/1.4912658 M3 - Conference contribution SN - 9780735412873 VL - 1648 BT - Proceedings of the International Conference on Numerical Analysis and Applied Mathematics 2014 (ICNAAM-2014) PB - American Institute of Physics Inc. ER - TY - GEN T1 - Graph-Based Map Matching for Indoor Positioning AU - Koivisto, Mike AU - Nurminen, Henri AU - Ali-Löytty, Simo AU - Piche, Robert N1 - ISBN of the USB proceedings. Will appear in IEEE Xplore. ORG=ase,0.8 ORG=mat,0.2 PY - 2015/12/1 Y1 - 2015/12/1 N2 - This article presents a probabilistic motion model that is based on an economical graph-based indoor map representation, such that the motion of the user is constrained according to the floor plan of a building. The floor plan is modeled as a combination of links and open space polygons that are connected by nodes. In the authors’ earlier work the link transition probabilities in this graph are proportional to the total link lengths that are the total lengths of the subgraphs accessible by choosing the considered link option, and this article extends this model to include open space polygons as well. A particle filter using the extended motion model in which all particles are constrained according to the map structure is presented. Furthermore, wireless local area network and Bluetooth Low Energy positioning tests show that the proposed algorithm outperforms comparison methods especially if the measurement rate is low. AB - This article presents a probabilistic motion model that is based on an economical graph-based indoor map representation, such that the motion of the user is constrained according to the floor plan of a building. The floor plan is modeled as a combination of links and open space polygons that are connected by nodes. In the authors’ earlier work the link transition probabilities in this graph are proportional to the total link lengths that are the total lengths of the subgraphs accessible by choosing the considered link option, and this article extends this model to include open space polygons as well. A particle filter using the extended motion model in which all particles are constrained according to the map structure is presented. Furthermore, wireless local area network and Bluetooth Low Energy positioning tests show that the proposed algorithm outperforms comparison methods especially if the measurement rate is low. KW - Indoor positioning KW - particle filter KW - motion model KW - map matching KW - graph U2 - 10.1109/ICICS.2015.7459983 DO - 10.1109/ICICS.2015.7459983 M3 - Conference contribution BT - 10th International Conference on Information, Communications and Signal Processing (ICICS) PB - IEEE ER - TY - GEN T1 - Hyperbolic laplace operator and the Weinstein equation in R3 AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - ei ut-numeroa 12.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: IKM PY - 2012 Y1 - 2012 M3 - Conference contribution T3 - International conference on the applications of computer science and mathematics in architecture and civil engineering SP - 15 BT - Proceedings in the 19th International Conference on the Applications of Computer Science and Mathematics in Architecture and Civil Engineering, IKM 2012, July 4-6 2012, Weimar, Germany A2 - Gürlebeck, K. A2 - Lahmer, T. A2 - Werner, F. PB - IKM CY - Weimar, Germany ER - TY - GEN T1 - Identifying weak ties from publicly available social media data in an event AU - Gupta, Jayesh Prakash AU - Menon, Karan AU - Kärkkäinen, Hannu AU - Huhtamäki, Jukka AU - Mukkamala, Raghava Rao AU - Hussain, Abid AU - Vatrapu, Ravi AU - Jussila, Jari AU - Pirkkalainen, Henri PY - 2016/10/17 Y1 - 2016/10/17 N2 - The concept of weak ties was introduced by Granovetter through the seminal paper titled "Strength of weak ties". Since then the role of weak ties in general and their specific role as occupying the structural hole has been explored in many different fields. In this study, we identify actual or potential weak ties using publicly available social media data in the context of an event. Our case study environment is community managers' online discussions in social media in connection to the yearly-organized Community Manager Appreciation Day (CMAD 2016) event in Finland. We were able to identify potential weak ties using the conversation based structural holes, making use of social network analysis methods (like clustering) and content analysis in the context of events. We add to the understanding of and useful data sources for the Strength of weak ties theory originated from Granovetter, and developed further by other researchers. Our approach may be used in future to make more sophisticated conference recommendation systems, and significantly automate the data extraction for making useful contact recommendations from them for conference participants. AB - The concept of weak ties was introduced by Granovetter through the seminal paper titled "Strength of weak ties". Since then the role of weak ties in general and their specific role as occupying the structural hole has been explored in many different fields. In this study, we identify actual or potential weak ties using publicly available social media data in the context of an event. Our case study environment is community managers' online discussions in social media in connection to the yearly-organized Community Manager Appreciation Day (CMAD 2016) event in Finland. We were able to identify potential weak ties using the conversation based structural holes, making use of social network analysis methods (like clustering) and content analysis in the context of events. We add to the understanding of and useful data sources for the Strength of weak ties theory originated from Granovetter, and developed further by other researchers. Our approach may be used in future to make more sophisticated conference recommendation systems, and significantly automate the data extraction for making useful contact recommendations from them for conference participants. KW - weak ties KW - social media UR - http://www.mindtrek.org/2016/ U2 - 10.1145/2994310.2994354 DO - 10.1145/2994310.2994354 M3 - Conference contribution SP - 11 EP - 19 BT - AcademicMindtrek '16 Proceedings of the 20th International Academic Mindtrek Conference PB - ACM ER - TY - GEN T1 - Improving engineering students' mathematics skills and analysing their behaviour using ICT - tools. AU - Pohjolainen, Seppo AU - Nykänen, Ossi AU - Venho, Janne AU - Kangas, Jussi N1 - Poistettu tupla r=2983

Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-11-29

Publisher name: European Society for Engineering Education SEFI PY - 2013 Y1 - 2013 M3 - Conference contribution T3 - Annual Conference of the European Society for Engineering Education SP - 1 EP - 8 BT - Proceedings of annual SEFI Conference, 16-20 September 2013, Leuven, Belgium PB - European Society for Engineering Education SEFI CY - Brussels, Belgium ER - TY - GEN T1 - Independent Loops Search in Flow Networks Aiming for Well-Conditioned System of Equations AU - Humaloja, Jukka-Pekka AU - Ali-Löytty, Simo AU - Pohjolainen, Seppo AU - Hämäläinen, Timo PY - 2017 Y1 - 2017 N2 - We approach the problem of choosing linearly independent loops in a pipeflow network as choosing the best-conditioned submatrix of a given larger matrix. We present some existing results of graph theory and submatrix selection problems, based on which we construct three heuristic algorithms for choosing the loops. The heuristics are tested on two pipeflow networks that differ significantly on the distribution of pipes and nodes in the network. AB - We approach the problem of choosing linearly independent loops in a pipeflow network as choosing the best-conditioned submatrix of a given larger matrix. We present some existing results of graph theory and submatrix selection problems, based on which we construct three heuristic algorithms for choosing the loops. The heuristics are tested on two pipeflow networks that differ significantly on the distribution of pipes and nodes in the network. KW - pipeflow analysis KW - independent loops U2 - 10.1007/978-3-319-63082-3 DO - 10.1007/978-3-319-63082-3 M3 - Conference contribution SN - 978-3-319-63081-6 T3 - Mathematics in industry BT - Progress in Industrial Mathematics at ECMI 2016 A2 - Quintela, Peregrina A2 - Barral, Patricia A2 - Gómez, Dolores A2 - Pena, Francisco J. A2 - Rodríguez, Jerónimo A2 - Salgado, Pilar A2 - Vázquez-Mendéz, Miguel E. PB - Springer International Publishing ER - TY - GEN T1 - Indoor positioning using WLAN coverage area estimates AU - Koski, Laura AU - Perälä, Tommi AU - Piche, Robert N1 - Poistettu tupla r=2937 (esitelmä-tietue)

Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1109/IPIN.2010.5648284 DO - 10.1109/IPIN.2010.5648284 M3 - Conference contribution SN - 978-1-4244-5862-2 SP - 1 EP - 7 BT - International Conference on Indoor Positioning and Indoor Navigation IPIN 2010, 15-17 September 2010, Zurich, Switzerland ER - TY - GEN T1 - Infinitesimals and Pavelka logic AU - Turunen, Esko AU - Navara, Mirko PY - 2015 Y1 - 2015 N2 - Rational Pavelka Logic does not admit infinitesimals. We argue that infinitesimals are important in logic and we present an alternative approach which admits them. It is built up in a similar style, but based on the Chang's perfect MV-algebra. We prove a partial result towards the completeness of this logic. We also discuss a combined approach using more complex perfect MV-algebras. AB - Rational Pavelka Logic does not admit infinitesimals. We argue that infinitesimals are important in logic and we present an alternative approach which admits them. It is built up in a similar style, but based on the Chang's perfect MV-algebra. We prove a partial result towards the completeness of this logic. We also discuss a combined approach using more complex perfect MV-algebras. KW - Mathematical fuzzy logic KW - Rational Pavelka Logic KW - Lukasiewicz operations KW - MV-algebra KW - perfect MV-algebra KW - Chang's MV-algebra KW - FUZZY LOGIC KW - PROPOSITIONAL CALCULI KW - TRUTH-CONSTANTS KW - COMPLETENESS U2 - 10.2991/ifsa-eusflat-15.2015.145 DO - 10.2991/ifsa-eusflat-15.2015.145 M3 - Conference contribution T3 - Advances in Intelligent Systems Research SP - 1027 EP - 1033 BT - PROCEEDINGS OF THE 2015 CONFERENCE OF THE INTERNATIONAL FUZZY SYSTEMS ASSOCIATION AND THE EUROPEAN SOCIETY FOR FUZZY LOGIC AND TECHNOLOGY A2 - Alonso, JM A2 - Bustince, H A2 - Reformat, M PB - Atlantis Press CY - PARIS ER - TY - GEN T1 - Infinite structure for infinite-dimensional systems: A directional approach AU - Laakkonen, Petteri AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Conference contribution SN - 978-963-311-370-7 SP - 659 EP - 666 BT - Proceedings of the 19th International Symposium on Mathematical Theory of Networks and Systems MTNS 2010, Budapest, Hungary, July 5-9, 2010 A2 - Edelmeyer, Andras ER - TY - GEN T1 - Information visualization of Twitter data for co-organizing conferences AU - Jussila, Jari AU - Huhtamäki, Jukka AU - Kärkkäinen, Hannu AU - Still, Kaisa N1 - Contribution: organisation=tlo,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5

Portfolio EDEND: 2013-12-29

Publisher name: ACM PY - 2013 Y1 - 2013 N2 - The aim of this research is to explore what kinds of insights information visualization of social media data can provide for co-organizing conferences. Our paper focuses on Twitter in ‘during-conference’ use. We present a case study based on CMAD2013 conference and on the tweet traffic during the conference day. We applied the process of data-driven visual network analysis for providing insights on Twitter use during CMAD2013 conference day. By analyzing the network of conference participants and the conference’s discussion topics, we were able to identify e.g. influential conference delegates, most interesting presentations and discussions, similarities between interests of the conference participants, and several development and information needs of conference co-organization derived from the information visualizations, which have implications for the planning and co-organizing of conferences, as well as for Twitter use in communicating during conferences. AB - The aim of this research is to explore what kinds of insights information visualization of social media data can provide for co-organizing conferences. Our paper focuses on Twitter in ‘during-conference’ use. We present a case study based on CMAD2013 conference and on the tweet traffic during the conference day. We applied the process of data-driven visual network analysis for providing insights on Twitter use during CMAD2013 conference day. By analyzing the network of conference participants and the conference’s discussion topics, we were able to identify e.g. influential conference delegates, most interesting presentations and discussions, similarities between interests of the conference participants, and several development and information needs of conference co-organization derived from the information visualizations, which have implications for the planning and co-organizing of conferences, as well as for Twitter use in communicating during conferences. U2 - 10.1145/2523429.2523482 DO - 10.1145/2523429.2523482 M3 - Conference contribution SN - 978-1-4503-1992-8 T3 - MindTrek Conference SP - 139 EP - 145 BT - 17th International Academic MindTrek Conference, October 1-4, 2013, Tampere, Finland PB - ACM CY - New York, NY ER - TY - GEN T1 - Launching context-aware visualisations AU - Salonen, Jaakko AU - Huhtamäki, Jukka N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 U2 - 10.1007/978-3-642-14859-0_12 DO - 10.1007/978-3-642-14859-0_12 M3 - Conference contribution SN - 978-3-642-14858-3 SP - 146 EP - 160 BT - Digital Eco-Systems. Third International Conference, OPAALS 2010, Aracuju, Sergipe, Brazil, March 22-23, 2010, Revised Selected Papers. Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering A2 - Colugnati, Fernando Antonio Basile A2 - Rodrigues, Lopes Lia Carrari A2 - Barretto, Saulo Faria Almeida ER - TY - GEN T1 - Least-Squares Transformations between Point-Sets AU - Rutanen, Kalle AU - Gomez-Herrero, German AU - Eriksson, Sirkka-Liisa AU - Egiazarian, Karen N1 - Contribution: organisation=mat,FACT1=0.5

Contribution: organisation=sgn,FACT2=0.5

Portfolio EDEND: 2013-10-29 PY - 2013 Y1 - 2013 U2 - 10.1007/978-3-642-38886-6_47 DO - 10.1007/978-3-642-38886-6_47 M3 - Conference contribution SN - 978-3-642-38885-9 T3 - Lecture Notes in Computer Science SP - 501 EP - 511 BT - Image Analysis, 18th Scandinavian Conference, SCIA 2013, Espoo, Finland, June 17-20, 2013, Proceedings A2 - Kämäräinen, Joni-Kristian A2 - Koskela, Markus PB - Springer CY - Berlin ER - TY - GEN T1 - Linear Equation Solvers: Comparison of LU Decomposition and a Robust ODE Solver AU - Pohjolainen, Seppo AU - Nortunen, Hari N1 - ei ut-numeroa 3.5.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution SN - 978-951-39-4331-8 T3 - CAO ECCOMAS Thematic Conference on Computational Analysis and Optimization SP - 77 EP - 80 BT - Proceedings of CAO2011 ECCOMAS Thematic Conference on Computational Analysis and Optimization, Jyväskylä, Finland, 9.6.-11.6.2011. Reports of the Department of Mathematical Information Technology. Series A Collections A2 - Repin, Sergey A2 - Tiihonen, Timo A2 - Tuovinen, Tero PB - University of Jyväskylä CY - Jyväskylä ER - TY - GEN T1 - Linear Model Predictive Control for Schrödinger Equation AU - Humaloja, Jukka-Pekka AU - Dubljevic, Stevan N1 - jufoid=65442 PY - 2018/8/9 Y1 - 2018/8/9 N2 - The paper considers the finite-horizon constrained optimal control problem for Schrödinger equation with boundary controls and boundary observations. The plant is mapped from continuous to discrete time using the Cayley-Tustin transform, which preserves input-output-stability of the plant. The proposed transformation is structure and energy preserving and does not induce order reduction associated with the spatial discretization. The controller design setting leads to the finite horizon constrained quadratic regulator problem, which is easily realized and accounts in explicit manner for input and output/state constraints. The model predictive control (MPC) design is realized for Schrödinger equation and the results are illustrated with numerical simulations showing successful stabilization of Schrödinger equation with simultaneous satisfaction of input and output/state constraints. AB - The paper considers the finite-horizon constrained optimal control problem for Schrödinger equation with boundary controls and boundary observations. The plant is mapped from continuous to discrete time using the Cayley-Tustin transform, which preserves input-output-stability of the plant. The proposed transformation is structure and energy preserving and does not induce order reduction associated with the spatial discretization. The controller design setting leads to the finite horizon constrained quadratic regulator problem, which is easily realized and accounts in explicit manner for input and output/state constraints. The model predictive control (MPC) design is realized for Schrödinger equation and the results are illustrated with numerical simulations showing successful stabilization of Schrödinger equation with simultaneous satisfaction of input and output/state constraints. U2 - 10.23919/ACC.2018.8431686 DO - 10.23919/ACC.2018.8431686 M3 - Conference contribution SN - 9781538654286 SP - 2569 EP - 2574 BT - 2018 Annual American Control Conference, ACC 2018 PB - IEEE ER - TY - GEN T1 - Massive-Scale Tree Modelling from TLS Data AU - Raumonen, P. AU - Casella, E. AU - Calders, K. AU - Murphy, S. AU - Åkerblom, M. AU - Kaasalainen, M. N1 - JUFOID=81104 PY - 2015 Y1 - 2015 N2 - This paper presents a method for reconstructing automatically the quantitative structure model of every tree in a forest plot from terrestrial laser scanner data. A new feature is the automatic extraction of individual trees from the point cloud. The method is tested with a 30-m diameter English oak plot and a 80-m diameter Australian eucalyptus plot. For the oak plot the total biomass was overestimated by about 17 %, when compared to allometry (N = 15), and the modelling time was about 100 min with a laptop. For the eucalyptus plot the total biomass was overestimated by about 8.5 %, when compared to a destructive reference (N = 27), and the modelling time was about 160 min. The method provides accurate and fast tree modelling abilities for, e. g., biomass estimation and ground truth data for airborne measurements at a massive ground scale. AB - This paper presents a method for reconstructing automatically the quantitative structure model of every tree in a forest plot from terrestrial laser scanner data. A new feature is the automatic extraction of individual trees from the point cloud. The method is tested with a 30-m diameter English oak plot and a 80-m diameter Australian eucalyptus plot. For the oak plot the total biomass was overestimated by about 17 %, when compared to allometry (N = 15), and the modelling time was about 100 min with a laptop. For the eucalyptus plot the total biomass was overestimated by about 8.5 %, when compared to a destructive reference (N = 27), and the modelling time was about 160 min. The method provides accurate and fast tree modelling abilities for, e. g., biomass estimation and ground truth data for airborne measurements at a massive ground scale. KW - quantitative structure model KW - automatic tree extraction KW - biomass KW - forest plot KW - ground truth KW - oak KW - eucalyptus KW - LiDAR KW - laser scanner data KW - terrestrial U2 - 10.5194/isprsannals-II-3-W4-189-2015 DO - 10.5194/isprsannals-II-3-W4-189-2015 M3 - Conference contribution VL - II-3/W4 T3 - International Archives of the Photogrammetry Remote Sensing and Spatial Information Sciences SP - 189 EP - 196 BT - ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences A2 - Stilla, U A2 - Heipke, C PB - COPERNICUS GESELLSCHAFT MBH CY - GOTTINGEN ER - TY - GEN T1 - Matematiikan kirjallinen kielentäminen yliopiston matematiikan opetuksessa AU - Joutsenlahti, Jorma AU - Sarikka, Hanna AU - Kangas, Jussi AU - Harjulehto, Petteri N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-11-29 PY - 2013 Y1 - 2013 M3 - Conference contribution SN - 978-951-39-5390-4 T3 - The annual conference of Finnish Mathematics and Science Education Research Association, November 8-9, 2012, Jyväskylä, Finland SP - 59 EP - 70 BT - Matematiikan ja luonnontieteiden opetuksen tutkimusseuran konferenssijulkaisu 2012. Tutkimuksia / Jyväskylän yliopisto, opettajankoulutuslaitos A2 - Hähkiöniemi, Markus A2 - Leppäaho, Henry A2 - Nieminen, Pasi A2 - Viiri, Jouni PB - University of Jyväskylä CY - Jyväskylä ER - TY - GEN T1 - Matematiikkaklinikka AU - Silius, Kirsi AU - Rautiainen, Emilia AU - Kangas, Jussi AU - Pohjolainen, Seppo AU - Miilumäki, Thumas N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Conference contribution SN - 978-952-60-3477-5 SP - 154 EP - 155 BT - ReflekTori 2010 Tekniikan opetuksen symposium 9.-10.2010, Espoo. Dipoli-raportit B A2 - Myller, Eeva PB - Aalto-yliopisto, Koulutuskeskus Dipoli CY - Espoo ER - TY - GEN T1 - Math-Bridge - Eurooppalainen silta lukio- ja korkeakoulumatematiikan välille AU - Miilumäki, Thumas AU - Pohjolainen, Seppo AU - Silius, Kirsi AU - Nykänen, Ossi AU - Kangas, Jussi N1 - Contribution: organisation=mat hyplab,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution T3 - ITK Interaktiivinen Tekniikka Koulutuksessa -konferenssi SP - 70 EP - 71 BT - ITK 2011, Interaktiivinen Tekniikka Koulutuksessa -konferenssi 2011 - Uutuuden viehätystä, ideoiden kierrätystä, Hämeenlinna, 6.-8.4.2011. Hämeen kesäyliopiston julkaisuja. Sarja B A2 - Leinamo, Sanna A2 - Salo, Hanna PB - Hämeen kesäyliopisto CY - Hämeenlinna ER - TY - GEN T1 - MathCheck: a tool for checking math solutions in detail AU - Valmari, Antti AU - Kaarakka, Terhi PY - 2016/9 Y1 - 2016/9 M3 - Conference contribution SN - 9782873520144 BT - SEFI 2016 Annual Conference Proceedings PB - European Society for Engineering Education SEFI ER - TY - GEN T1 - Mathematics Remedial Instruction with Math-Bridge e-learning system AU - Kangas, Jussi AU - Miilumäki, Thumas AU - Pohjolainen, Seppo N1 - Poistetty tupla r=3459. ei ut-numeroa 19.8.2013

Contribution: organisation=mat hyplab,FACT1=1

Publisher name: Universidad de Salamanca PY - 2012 Y1 - 2012 M3 - Conference contribution SN - 978-84-695-3960-6 T3 - SEFI MWG Seminar BT - 16th SEFI MWG Seminar - Mathematical Education of Engineers, Salamanca, Spain, 28.-30.6.2012 A2 - Alpers, Burkhard A2 - Robinson, Carol A2 - Rodriguez, Gerardo A2 - Martin, Angel A2 - de la Villa, Agustin PB - Universidad de Salamanca CY - Salamanca, Spain ER - TY - GEN T1 - Mean value properties for K-hypermonogenic functions AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - ei ut-numeroa 1.3.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution T3 - International Conference on Clifford Algebras and their Applications in Mathematical Physics SP - 1 EP - 11 BT - 9th International Conference on Clifford Algebras and their Applications in Mathematical Physics 15 - 20 July 2011, Weimar, Germany A2 - Gurlebeck, K. PB - ICCA9 CY - Weimar ER - TY - GEN T1 - Minimal Solutions of Fuzzy Relation Equations with General Operators on the Unit Interval AU - Medina, Jesus AU - Turunen, Esko AU - Bartl, Eduard AU - Diaz-Moreno, Juan Carlos N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-10-03

Publisher name: Springer International Publishing PY - 2014 Y1 - 2014 U2 - 10.1007/978-3-319-08852-5_9 DO - 10.1007/978-3-319-08852-5_9 M3 - Conference contribution SN - 978-3-319-08851-8 T3 - Communications in Computer and Information Science SP - 81 EP - 90 BT - Information Processing and Management of Uncertainty in Knowledge-Based Systems. 15th International Conference, IPMU 2014, Montpellier, France, July 15-19, 2014, Proceedings, Part III. Communications in Computer and Information Science PB - Springer International Publishing ER - TY - GEN T1 - Mobile tracking and parameter learning in unknown non-line-of-sight conditions AU - Liang, Chen AU - Piche, Robert N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 N2 - This paper studies the mobile tracking problem in mixed line-of-sight (LOS) and non-line-of-sight (NLOS) conditions, where the statistics of NLOS error is Gaussian with fixed but unknown mean and variance. A Rao-Blackwellized particle filtering and parameter learning method (RBPF-PL) is proposed, in which the particle filtering with optimal trial distribution is first applied to estimate the posterior density of sight conditions, then the decentralized extended Kalman filter (EKF) is used to estimate the mobile state. In the parameter learning step, using the conjugate prior distribution on the unknown parameters, the posterior distribution of unknown parameters is further updated according to the sufficient statistics. Simulation results show the RBPF-PL method is effective to infer the unknown NLOS parameter and could achieve good tracking performance using small number of particles. AB - This paper studies the mobile tracking problem in mixed line-of-sight (LOS) and non-line-of-sight (NLOS) conditions, where the statistics of NLOS error is Gaussian with fixed but unknown mean and variance. A Rao-Blackwellized particle filtering and parameter learning method (RBPF-PL) is proposed, in which the particle filtering with optimal trial distribution is first applied to estimate the posterior density of sight conditions, then the decentralized extended Kalman filter (EKF) is used to estimate the mobile state. In the parameter learning step, using the conjugate prior distribution on the unknown parameters, the posterior distribution of unknown parameters is further updated according to the sufficient statistics. Simulation results show the RBPF-PL method is effective to infer the unknown NLOS parameter and could achieve good tracking performance using small number of particles. M3 - Conference contribution SN - 978-0-9824438-1-1 SP - 1 EP - 6 BT - 13th International Conference on Information Fusion, 26-29 July 2010, EICC, Edinburgh, UK ER - TY - GEN T1 - Modeling growth in neuronal cell cultures: network properties in different phases of growth studied using two growth simulators AU - Mäki-Marttunen, Tuomo AU - Havela, Riikka AU - Acimovic, Jugoslava AU - Teppola, Heidi AU - Ruohonen, Keijo AU - Linne, Marja-Leena N1 - Contribution: organisation=sgn,FACT1=0.5

Contribution: organisation=mat,FACT2=0.5 PY - 2010 Y1 - 2010 N2 - In this work we study the structural changes in neuronal networks emerging during network maturation. We analyze two computational models proposed in the literature that describe the growth of neurons. The models have planar geometry and the density of cells is chosen to correspond to the ’dense’ and ’sparse’ cultures reported in the experimental studies. The growth of the model neurons and networks is simulated using two novel publicly available simulators. A graph representation of the networks is obtained from the simulation results and examined at days 7, 14, and 21. The two models are clearly different in nature. The first can model large networks phenomenologically, while the second describes some of the relevant biophysical processes in smaller networks. The difference in modeling approach is evident in the graph properties. AB - In this work we study the structural changes in neuronal networks emerging during network maturation. We analyze two computational models proposed in the literature that describe the growth of neurons. The models have planar geometry and the density of cells is chosen to correspond to the ’dense’ and ’sparse’ cultures reported in the experimental studies. The growth of the model neurons and networks is simulated using two novel publicly available simulators. A graph representation of the networks is obtained from the simulation results and examined at days 7, 14, and 21. The two models are clearly different in nature. The first can model large networks phenomenologically, while the second describes some of the relevant biophysical processes in smaller networks. The difference in modeling approach is evident in the graph properties. M3 - Conference contribution SN - 978-952-15-2384-7 SP - 4 p BT - Proceedings of the Seventh International Workshop on Computational Systems Biology, WCSB 2010, Luxembourg, June 16-18, 2010. TICSP Series A2 - Nykter, Matti A2 - Ruusuvuori, Pekka A2 - Carlberg, Carsten A2 - Yli-Harja, Olli ER - TY - GEN T1 - Modelling of Joule heating based self-alignment method for metal grid line passivation AU - Janka, Marika AU - Raumonen, Pasi AU - Tuukkanen, Sampo AU - Lupo, Donald N1 - Contribution: organisation=elt,FACT1=0.8

Contribution: organisation=mat,FACT2=0.2

Portfolio EDEND: 2014-05-08

Publisher name: Materials Research Society PY - 2014 Y1 - 2014 N2 - A Joule heating based self-alignment method for solution-processable insulator structures has been modeled for the passivation of metal grid lines, for example for organic light emitting diodes or photovoltaic cells. To minimize overhang of the passivation layer from line edges, we have studied the Joule heating approach using solution-processable, cross-linkable polymer insulator films. Finite element simulations were performed to investigate the heating of the sample using glass and poly(ethylene terephthalate) (PET) substrates. The sample was at room temperature and the current was selected to induce a temperature of 410 K at the conductor. It was found that the selection of substrate material is crucial for the localization of cross-linking. For a PET substrate, the temperature gradient at the edge of the conductor is approximately twice the gradient for glass. As a result, using a glass substrate demands high selectivity from the polymer cross-linking, thus making PET a more suitable substrate material for our application. A flexible PET substrate is, in addition, compatible with roll-to-roll mass-manufacturing processes. AB - A Joule heating based self-alignment method for solution-processable insulator structures has been modeled for the passivation of metal grid lines, for example for organic light emitting diodes or photovoltaic cells. To minimize overhang of the passivation layer from line edges, we have studied the Joule heating approach using solution-processable, cross-linkable polymer insulator films. Finite element simulations were performed to investigate the heating of the sample using glass and poly(ethylene terephthalate) (PET) substrates. The sample was at room temperature and the current was selected to induce a temperature of 410 K at the conductor. It was found that the selection of substrate material is crucial for the localization of cross-linking. For a PET substrate, the temperature gradient at the edge of the conductor is approximately twice the gradient for glass. As a result, using a glass substrate demands high selectivity from the polymer cross-linking, thus making PET a more suitable substrate material for our application. A flexible PET substrate is, in addition, compatible with roll-to-roll mass-manufacturing processes. U2 - 10.1557/opl.2014.127 DO - 10.1557/opl.2014.127 M3 - Conference contribution BT - 2013 MRS Fall Meeting - Symposium M - Large-Area Processing and Patterning for Active Optical and Electronic Devices PB - MATERIALS RESEARCH SOCIETY ER - TY - GEN T1 - Moodlen työpaja T2 - Vertaisarviointi osana opetusta yliopistomatematiikan ensimmäisellä peruskurssilla AU - Mäkelä, Ari-Mikko AU - Ali-Löytty, Simo AU - Joutsenlahti, Jorma AU - Kauhanen, Janne N1 - INT=mat,"Joutsenlahti, Jorma" PY - 2016 Y1 - 2016 KW - Moodle KW - työpaja KW - workshop M3 - Conference contribution SP - 90 EP - 99 BT - Matematiikan ja luonnontieteiden opetuksen tutkimusseuran tutkimuspäivät 2015 A2 - Silfvenberg, Harry A2 - Hästö, Peter PB - Matematiikan ja luonnontiteiden opetuksen tutkimusseura r.y. ER - TY - GEN T1 - Motion Model for Positioning with Graph-Based Indoor Map AU - Nurminen, Henri AU - Koivisto, Mike AU - Ali-Löytty, Simo AU - Piche, Robert N1 - ORG=ase,0.8 ORG=mat,0.2 PY - 2015 Y1 - 2015 N2 - This article presents a training-free probabilistic pedestrian motion model that uses indoor map information represented as a set of links that are connected by nodes. This kind of structure can be modelled as a graph. In the proposed model, as a position estimate reaches a link end, the choice probabilities of the next link are proportional to the total link lengths (TLL), the total lengths of the subgraphs accessible by choosing the considered link alternative. The TLLs can be computed off-line using only the graph, and they can be updated if training data are available. A particle filter in which all the particles move on the links following the TLL-based motion model is formulated. The TLL-based motion model has advantageous theoretical properties compared to the conventional models. Furthermore, the real-data WLAN positioning tests show that the positioning accuracy of the algorithm is similar or in many cases better than that of the conventional algorithms. The TLL-based model is found to be advantageous especially if position measurements are used infrequently, with 10-second or more time intervals. AB - This article presents a training-free probabilistic pedestrian motion model that uses indoor map information represented as a set of links that are connected by nodes. This kind of structure can be modelled as a graph. In the proposed model, as a position estimate reaches a link end, the choice probabilities of the next link are proportional to the total link lengths (TLL), the total lengths of the subgraphs accessible by choosing the considered link alternative. The TLLs can be computed off-line using only the graph, and they can be updated if training data are available. A particle filter in which all the particles move on the links following the TLL-based motion model is formulated. The TLL-based motion model has advantageous theoretical properties compared to the conventional models. Furthermore, the real-data WLAN positioning tests show that the positioning accuracy of the algorithm is similar or in many cases better than that of the conventional algorithms. The TLL-based model is found to be advantageous especially if position measurements are used infrequently, with 10-second or more time intervals. U2 - 10.1109/IPIN.2014.7275539 DO - 10.1109/IPIN.2014.7275539 M3 - Conference contribution SP - 646 EP - 655 BT - 2014 International Conference on Indoor Positioning and Indoor Navigation (IPIN), 27-30 Oct. 2014, Busan, South Korea PB - IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Motivating the Mathematics Studies by Real-life Examples of Signal Processing and Communications Engineering AU - Huttunen, Heikki AU - Valkama, Mikko AU - Talvitie, Jukka AU - Laaksonen, Merja N1 - Contribution: organisation=sgn,FACT1=0.34

Contribution: organisation=tlt,FACT2=0.33

Contribution: organisation=mat,FACT3=0.33 PY - 2011 Y1 - 2011 U2 - 10.1109/DSP-SPE.2011.5739213 DO - 10.1109/DSP-SPE.2011.5739213 M3 - Conference contribution SN - 978-1-61284-226-4 T3 - IEEE Digital Signal Processing Workshop and IEEE Signal Processing Education Workshop DSP/SPE SP - 1 EP - 6 BT - 2011 IEEE Digital Signal Processing Workshop and IEEE Signal Processing Education Workshop (DSP/SPE), Sedona, USA, 4-7 January 2011 PB - IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Networks of Growth: Case Young Innovative Companies in Finland AU - Huhtamäki, Jukka AU - Still, Kaisa AU - Isomursu, Minna AU - Russell, Martha G. AU - Rubens, Neil N1 - ei ut-numeroa 13.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Academic Publishing International Limited PY - 2012 Y1 - 2012 M3 - Conference contribution SN - 978-1-908272-68-3 T3 - European Conference on Innovation and Entrepreneurship BT - Proceedings of the 7th European Conference on Innovation and Entrepreneurship, September 20-21, 2012, Santarem, Portugal A2 - Vivas, C. A2 - Lucas, F. PB - Academic Publishing International Limited CY - Reading, UK ER - TY - GEN T1 - Networks of innovation relationships: multiscopic views on Finland AU - Still, Kaisa AU - Huhtamäki, Jukka AU - Russell, Martha G. AU - Basole, Rahul C. AU - Salonen, Jaakko AU - Rubens, Neil N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: International Society for Professional Innovation Management ISPIM PY - 2013 Y1 - 2013 M3 - Conference contribution SN - 978-952-265-420-5 T3 - International Society for Professional Innovation Management Conference SP - 1 EP - 15 BT - XXIV ISPIM Conference, Innovating in Global Markets: Challenges for Sustainable Growth, 16-19 June 2013, Helsinki, Finland A2 - Huizingh, K.R.E. A2 - Conn, S. A2 - Torkkeli, M. A2 - Schneider, S. A2 - Bitran, I. PB - International Society for Professional Innovation Management ISPIM CY - Manchester, UK ER - TY - GEN T1 - New era of Business Analytics - Making sense of business ecosystems AU - Jussila, Jari AU - Kärkkäinen, Hannu AU - Kortelainen, Samuli AU - Huhtamäki, Jukka AU - Aho, Timo AU - Tebest, Teemo N1 - Contribution: organisation=tlo,FACT1=0.67

Contribution: organisation=mat,FACT2=0.33

Portfolio EDEND: 2014-12-31

Publisher name: ACM PY - 2014 Y1 - 2014 U2 - 10.1145/2676467.2676517 DO - 10.1145/2676467.2676517 M3 - Conference contribution SN - 978-1-4503-3006-0 T3 - MindTrek Conference SP - 276 EP - 278 BT - Academic MindTrek Conference 2014, Tampere, Finland, November 4-6, 2014 A2 - Lugmayr, Artur A2 - Franssila, Heljä A2 - Paavilainen, Janne PB - ACM CY - New York, NY ER - TY - GEN T1 - Non-classical Logics with Real Life Applications AU - Turunen, Esko N1 - First published 2011

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution SN - 978-81-8387-417-5 T3 - International Conference of Rough Sets, Fuzzy Setsand Soft Computing ICRSFSSC SP - 171 EP - 178 BT - Proceedings of International Conference of Rough Sets, Fuzzy Sets and Soft Computing ICRSFSSC-2009, November 5-7 2009, Tripura University PB - Serial Publications CY - New Delhi ER - TY - GEN T1 - Normal Distributions Transform Occupancy Maps: Application to Large-Scale Online 3D Mapping AU - Saarinen, Jari AU - Andreasson, Henrik AU - Stoyanov, Todor AU - Ala-Luhtala, Juha AU - Lilienthal, Achim J. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-07-29

Publisher name: IEEE PY - 2013 Y1 - 2013 U2 - 10.1109/ICRA.2013.6630878 DO - 10.1109/ICRA.2013.6630878 M3 - Conference contribution SN - 978-1-4673-5641-1 T3 - IEEE International Conference on Robotics and Automation SP - 2233 EP - 2238 BT - 2013 IEEE International conference on Robotics and Automation, ICRA, May 6-10, 2013, Karlsruhe, Germany PB - IEEE CY - Piscataway, NJ ER - TY - GEN T1 - NP-completeness results for partitioning a graph into total dominating sets AU - Koivisto, Mikko AU - Laakkonen, Petteri AU - Lauri, Juho N1 - jufoid=62555 PY - 2017 Y1 - 2017 N2 - A total domatic k-partition of a graph is a partition of its vertex set into k subsets such that each intersects the open neighborhood of each vertex. The maximum k for which a total domatic k-partition exists is known as the total domatic number of a graph G, denoted by d:t(G). We extend considerably the known hardness results by showing it istextsc {NP} -complete to decide whether d:t(G)ge 3 where G is a bipartite planar graph of bounded maximum degree. Similarly, for every kge 3, it istextsc {NP} -complete to decide whether d:t(G)ge k, where G is a split graph or k-regular. In particular, these results complement recent combinatorial results regarding d:t(G) on some of these graph classes by showing that the known results are, in a sense, best possible. Finally, for general n-vertex graphs, we show the problem is solvable in 2^n n^{O(1)} time, and derive even faster algorithms for special graph classes. AB - A total domatic k-partition of a graph is a partition of its vertex set into k subsets such that each intersects the open neighborhood of each vertex. The maximum k for which a total domatic k-partition exists is known as the total domatic number of a graph G, denoted by d:t(G). We extend considerably the known hardness results by showing it istextsc {NP} -complete to decide whether d:t(G)ge 3 where G is a bipartite planar graph of bounded maximum degree. Similarly, for every kge 3, it istextsc {NP} -complete to decide whether d:t(G)ge k, where G is a split graph or k-regular. In particular, these results complement recent combinatorial results regarding d:t(G) on some of these graph classes by showing that the known results are, in a sense, best possible. Finally, for general n-vertex graphs, we show the problem is solvable in 2^n n^{O(1)} time, and derive even faster algorithms for special graph classes. U2 - 10.1007/978-3-319-62389-4_28 DO - 10.1007/978-3-319-62389-4_28 M3 - Conference contribution SN - 9783319623887 T3 - Lecture Notes in Computer Science SP - 333 EP - 345 BT - Computing and Combinatorics - 23rd International Conference, COCOON 2017, Proceedings PB - Springer Verlag ER - TY - GEN T1 - On Convergence and Accuracy of State-Space Approximations of Squared Exponential Covariance Functions AU - Särkkä, Simo AU - Piche, Robert N1 - Contribution: organisation=ase,FACT1=1

Portfolio EDEND: 2014-11-21 PY - 2014 Y1 - 2014 U2 - 10.1109/MLSP.2014.6958890 DO - 10.1109/MLSP.2014.6958890 M3 - Conference contribution SN - 978-1-4799-3694-6 SP - 1 EP - 6 BT - 2014 IEEE International Workshop on Machine Learning for Signal Processing (MLSP), September 21-24, 2014, Reims, France PB - Institute of Electrical and Electronics Engineers CY - Piscataway ER - TY - GEN T1 - On Detecting the Shape of an Unknown Object in an Electric Field AU - Humaloja, Jukka-Pekka AU - Hämäläinen, Timo AU - Pohjolainen, Seppo PY - 2016 Y1 - 2016 N2 - The problem discussed in this paper is detecting the shape of an unknown object in a 2-dimensional static electric field. For simplicity, the problem is defined in a partially rectangular domain, where on a part of the boundary the potential and/or its normal derivative are known. On the other part of the boundary the boundary curve is unknown, and this curve is to be determined. The unknown part of the boundary curve describes the shape of the unknown object.The problem is defined in the complex plane by an analytic function w=f(z) = u(x,y)+iv(x,y) with the potential u as its real part. Then the inverse function is given as f^{-1}(w) = x(u,v)+iy(u,v), where the functions x and y are harmonic in a rectangle with an unknown boundary condition on one boundary. The alternating-field technique is used to solve the unknown boundary condition. AB - The problem discussed in this paper is detecting the shape of an unknown object in a 2-dimensional static electric field. For simplicity, the problem is defined in a partially rectangular domain, where on a part of the boundary the potential and/or its normal derivative are known. On the other part of the boundary the boundary curve is unknown, and this curve is to be determined. The unknown part of the boundary curve describes the shape of the unknown object.The problem is defined in the complex plane by an analytic function w=f(z) = u(x,y)+iv(x,y) with the potential u as its real part. Then the inverse function is given as f^{-1}(w) = x(u,v)+iy(u,v), where the functions x and y are harmonic in a rectangle with an unknown boundary condition on one boundary. The alternating-field technique is used to solve the unknown boundary condition. KW - free boundary problem KW - industrial mathematics U2 - 10.1007/978-3-319-23413-7 DO - 10.1007/978-3-319-23413-7 M3 - Conference contribution SN - 978-3-319-23412-0 T3 - Mathematics in Industry BT - Progress in Industrial Mathematics at ECMI 2014 A2 - Russo, G. A2 - Capasso, V. A2 - Nicosia, G. A2 - Romano, V. PB - Springer International Publishing ER - TY - GEN T1 - On Hodge-de Rham systems in hyperbolic Clifford analysis AU - Eriksson, Sirkka-Liisa AU - Orelma, Heikki N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-11-29

Publisher name: American Institute of Physics AIP PY - 2013 Y1 - 2013 U2 - 10.1063/1.4825535 DO - 10.1063/1.4825535 M3 - Conference contribution SN - 978-0-7354-1184-5 T3 - AIP Conference Proceedings SP - 492 EP - 495 BT - 11th International Conference of Numerical Analysis and Applied Mathematics, ICNAAM 2013, 21-27 September 2013, Rhodes, Greece PB - American Institute of Physics AIP ER - TY - GEN T1 - On improvement of transient stage of composite nonlinear feedback control using arbitrary order set point filters AU - Pyrhönen, Veli-Pekka AU - Koivisto, Hannu PY - 2015/4/1 Y1 - 2015/4/1 N2 - This paper studies the generalization of composite nonlinear feedback (CNF) control using arbitrary order set point filters, which focus on the initial stage of the transient response. The set point filters can be used to provide more performance by shortening the rise and settling times of the control system. Furthermore, the filters operate outside the feedback loop, and hence, they do not sacrifice loop robustness. The new method is illustrated by a benchmark problem found in an open literature. The simulation results show that the proposed method improves the set point response more than 10% in terms of settling time. AB - This paper studies the generalization of composite nonlinear feedback (CNF) control using arbitrary order set point filters, which focus on the initial stage of the transient response. The set point filters can be used to provide more performance by shortening the rise and settling times of the control system. Furthermore, the filters operate outside the feedback loop, and hence, they do not sacrifice loop robustness. The new method is illustrated by a benchmark problem found in an open literature. The simulation results show that the proposed method improves the set point response more than 10% in terms of settling time. KW - Composite nonlinear feedback KW - actuator saturation KW - high performance KW - robust control KW - set point filter KW - control system synthesis KW - feedback KW - nonlinear control systems KW - transient response U2 - 10.1109/ICCSCE.2014.7072705 DO - 10.1109/ICCSCE.2014.7072705 M3 - Conference contribution SN - 978-1-4799-5685-2 SP - 147 EP - 152 BT - 2014 IEEE International Conference on Control System, Computing and Engineering (ICCSCE) PB - Institute of Electrical and Electronics Engineers IEEE ER - TY - GEN T1 - On polynomial stability of linear systems AU - Paunonen, Lassi AU - Laakkonen, Petteri N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-31

Publisher name: University of Groningen PY - 2014 Y1 - 2014 M3 - Conference contribution SN - 978-90-367-6321-9 T3 - International Symposium on Mathematical Theory of Networks and Systems SP - 233 EP - 238 BT - 21st International Symposium on Mathematical Theory of Networks and Systems, MTNS 2014, July 7-11, 2014, Groningen, the Netherlands PB - University of Groningen CY - Groningen, the Netherlands ER - TY - GEN T1 - On Robust Output Regulation for Continuous-Time Periodic Systems AU - Paunonen, Lassi PY - 2015 Y1 - 2015 N2 - We construct a controller to solve robust output tracking problem for a stable linear continuous-time periodic system on a finite-dimensional space. We begin by transforming the time-dependent plant to a time-invariant discrete-time system using the ``lifting technique''. The controller is then designed to achieve robust output tracking for the lifted system. We show that an exact solution to the control problem for a continuous-time periodic system necessarily requires an error feedback controller with an infinite-dimensional internal model. The results are illustrated with an example where robust output tracking is considered for a stable periodic scalar system. AB - We construct a controller to solve robust output tracking problem for a stable linear continuous-time periodic system on a finite-dimensional space. We begin by transforming the time-dependent plant to a time-invariant discrete-time system using the ``lifting technique''. The controller is then designed to achieve robust output tracking for the lifted system. We show that an exact solution to the control problem for a continuous-time periodic system necessarily requires an error feedback controller with an infinite-dimensional internal model. The results are illustrated with an example where robust output tracking is considered for a stable periodic scalar system. U2 - 10.1137/1.9781611974072.7 DO - 10.1137/1.9781611974072.7 M3 - Conference contribution BT - 2015 Proceedings of the SIAM Conference on Control and its Applications PB - SIAM, Society for Industrial and Applied Mathematics ER - TY - GEN T1 - On the Complexity of Rainbow Coloring Problems AU - Eiben, Eduard AU - Ganian, Robert AU - Lauri, Juho N1 - JUFOID=62555 PY - 2016/2/20 Y1 - 2016/2/20 N2 - An edge-colored graph G is said to be rainbow connected if between each pair of vertices there exists a path which uses each color at most once. The rainbow connection number, denoted by rc(G), is the minimum number of colors needed to make G rainbow connected. Along with its variants, which consider vertex colorings and/or so-called strong colorings, the rainbow connection number has been studied from both the algorithmic and graph-theoretic points of view.In this paper we present a range of new results on the computational complexity of computing the four major variants of the rainbow connection number. In particular, we prove that the Strong Rainbow Vertex Coloring problem is NP-complete even on graphs of diameter 3. We show that when the number of colors is fixed, then all of the considered problems can be solved in linear time on graphs of bounded treewidth. Moreover, we provide a linear-time algorithm which decides whether it is possible to obtain a rainbow coloring by saving a fixed number of colors from a trivial upper bound. Finally, we give a linear-time algorithm for computing the exact rainbow connection numbers for three variants of the problem on graphs of bounded vertex cover number. AB - An edge-colored graph G is said to be rainbow connected if between each pair of vertices there exists a path which uses each color at most once. The rainbow connection number, denoted by rc(G), is the minimum number of colors needed to make G rainbow connected. Along with its variants, which consider vertex colorings and/or so-called strong colorings, the rainbow connection number has been studied from both the algorithmic and graph-theoretic points of view.In this paper we present a range of new results on the computational complexity of computing the four major variants of the rainbow connection number. In particular, we prove that the Strong Rainbow Vertex Coloring problem is NP-complete even on graphs of diameter 3. We show that when the number of colors is fixed, then all of the considered problems can be solved in linear time on graphs of bounded treewidth. Moreover, we provide a linear-time algorithm which decides whether it is possible to obtain a rainbow coloring by saving a fixed number of colors from a trivial upper bound. Finally, we give a linear-time algorithm for computing the exact rainbow connection numbers for three variants of the problem on graphs of bounded vertex cover number. UR - http://iwoca2015.di.univr.it/ U2 - 10.1007/978-3-319-29516-9_18 DO - 10.1007/978-3-319-29516-9_18 M3 - Conference contribution SN - 978-3-319-29515-2 T3 - Lecture Notes in Computer Science SP - 209 EP - 220 BT - Combinatorial Algorithms A2 - Lipták, Zsuzsanna A2 - Smyth, William F. PB - Springer International Publishing ER - TY - GEN T1 - On the Fine-Grained Complexity of Rainbow Coloring AU - Kowalik, Lukasz AU - Lauri, Juho AU - Socala, Arkadiusz N1 - JUFOID=79091 PY - 2016 Y1 - 2016 N2 - The Rainbow k-Coloring problem asks whether the edges of a given graph can be colored in k colors so that every pair of vertices is connected by a rainbow path, i.e., a path with all edges of different colors. Our main result states that for any k >= 2, there is no algorithm for Rainbow k-Coloring running in time 2^{o(n^{3/2})}, unless ETH fails. Motivated by this negative result we consider two parameterized variants of the problem. In the Subset Rainbow k-Coloring problem, introduced by Chakraborty et al. [STACS 2009, J. Comb. Opt. 2009], we are additionally given a set S of pairs of vertices and we ask if there is a coloring in which all the pairs in S are connected by rainbow paths. We show that Subset Rainbow k-Coloring is FPT when parameterized by |S|. We also study Subset Rainbow k-Coloring problem, where we are additionally given an integer q and we ask if there is a coloring in which at least q anti-edges are connected by rainbow paths. We show that the problem is FPT when parameterized by q and has a kernel of size O(q) for every k >= 2, extending the result of Ananth et al. [FSTTCS 2011]. We believe that our techniques used for the lower bounds may shed some light on the complexity of the classical Edge Coloring problem, where it is a major open question if a 2^{O(n)}-time algorithm exists. AB - The Rainbow k-Coloring problem asks whether the edges of a given graph can be colored in k colors so that every pair of vertices is connected by a rainbow path, i.e., a path with all edges of different colors. Our main result states that for any k >= 2, there is no algorithm for Rainbow k-Coloring running in time 2^{o(n^{3/2})}, unless ETH fails. Motivated by this negative result we consider two parameterized variants of the problem. In the Subset Rainbow k-Coloring problem, introduced by Chakraborty et al. [STACS 2009, J. Comb. Opt. 2009], we are additionally given a set S of pairs of vertices and we ask if there is a coloring in which all the pairs in S are connected by rainbow paths. We show that Subset Rainbow k-Coloring is FPT when parameterized by |S|. We also study Subset Rainbow k-Coloring problem, where we are additionally given an integer q and we ask if there is a coloring in which at least q anti-edges are connected by rainbow paths. We show that the problem is FPT when parameterized by q and has a kernel of size O(q) for every k >= 2, extending the result of Ananth et al. [FSTTCS 2011]. We believe that our techniques used for the lower bounds may shed some light on the complexity of the classical Edge Coloring problem, where it is a major open question if a 2^{O(n)}-time algorithm exists. KW - graph coloring KW - computational complexity KW - lower bounds KW - exponential time hypothesis KW - FPT algorithms U2 - 10.4230/LIPIcs.ESA.2016.58 DO - 10.4230/LIPIcs.ESA.2016.58 M3 - Conference contribution VL - 57 T3 - Leibniz International Proceedings in Informatics (LIPIcs) BT - 24th Annual European Symposium on Algorithms (ESA 2016) A2 - Sankowski, Piotr A2 - Zaroliagis, Christos ER - TY - GEN T1 - On the Structure of Robust Controllers for Infinite-Dimensional Systems AU - Hämäläinen, Timo AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: European Control Association EUCA PY - 2013 Y1 - 2013 M3 - Conference contribution SN - 978-3-9524173-4-8 T3 - European Control Conference SP - 59 EP - 62 BT - 12th European Control Conference, ECC 2013, Zürich, Switzerland, 17.-19.7.2013 PB - European Control Association EUCA CY - Zürich, Sveitsi ER - TY - GEN T1 - On the Structure of Robust Controllers for Infinite-Dimensional Systems AU - Hämäläinen, Timo AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2014-12-30

Publisher name: University of Groningen PY - 2014 Y1 - 2014 M3 - Conference contribution SN - 978-90-367-6321-9 SP - 938 EP - 941 BT - 21st International Symposium on Mathematical Theory of Networks and Systems, MTNS 2014, July 7-11, 2014, Groningen, The Netherlands PB - University of Groningen CY - Groningen, the Netherlands ER - TY - GEN T1 - Opiskelijoiden oppimistyökalujen käyttö tietokoneavusteisessa Matematiikkajumppa -tukiopetuksessa AU - Myllykoski, Tuomas AU - Ali-Löytty, Simo Sakari AU - Pohjolainen, Seppo PY - 2017/10/31 Y1 - 2017/10/31 N2 - Tampereen teknillisessä yliopistossa aloittavat uudet opiskelijat ovat vuodesta 2002 lähtien suorittaneet opintojensa aluksi koulumatematiikan osaamista mittaavan matematiikan perustaitotestin. Opiskelijat, joiden matemaattiset perustaidot eivät testin perusteella ole olleet riittävät, on ohjattu matematiikkajumppaan: tukiopetusohjelmaan, joka suoritetaan verkkopohjaisesti opiskelijan omalla ajalla. Tässä tutkimuksessa selvitettiin miten ja mitä oppimistyökaluja opiskelijat käyttivät verkkopohjaisessa tukiopetuksessa. Tutkimuksessa havaittiin, että erilaiset oppijat toimivat eri tavalla suorittaessaan matematiikkajumppaa. Pintasuuntautuneet oppijat käyttävät paljon erilaisia työkaluja, kun taas osaajat käyttävät huomattavasti vähemmän työkaluja, ja he menestyvät tentissä pintasuuntautuneita opiskelijoita paremmin. AB - Tampereen teknillisessä yliopistossa aloittavat uudet opiskelijat ovat vuodesta 2002 lähtien suorittaneet opintojensa aluksi koulumatematiikan osaamista mittaavan matematiikan perustaitotestin. Opiskelijat, joiden matemaattiset perustaidot eivät testin perusteella ole olleet riittävät, on ohjattu matematiikkajumppaan: tukiopetusohjelmaan, joka suoritetaan verkkopohjaisesti opiskelijan omalla ajalla. Tässä tutkimuksessa selvitettiin miten ja mitä oppimistyökaluja opiskelijat käyttivät verkkopohjaisessa tukiopetuksessa. Tutkimuksessa havaittiin, että erilaiset oppijat toimivat eri tavalla suorittaessaan matematiikkajumppaa. Pintasuuntautuneet oppijat käyttävät paljon erilaisia työkaluja, kun taas osaajat käyttävät huomattavasti vähemmän työkaluja, ja he menestyvät tentissä pintasuuntautuneita opiskelijoita paremmin. M3 - Conference contribution T3 - Proceedings of the FMSERA annual symposium SP - 54 EP - 65 BT - 2017: Proceedings of the annual FMSERA symposium 2016 ER - TY - GEN T1 - Optimal combination of data modes in inverse problems: maximum compatibility estimate AU - Kaasalainen, Mikko N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Conference contribution SP - 365 EP - 372 BT - Progress in Analysis and Its Applications: Proceedings of the 7th international ISAAC Congress, London, UK, 13-18 July, 2010 A2 - Ruzhansky, Michael A2 - Wirth, Jens ER - TY - GEN T1 - Order reduction for a signaling pathway model of neuronal synaptic plasticity AU - Lehtimäki, Mikko AU - Paunonen, Lassi AU - Pohjolainen, Seppo AU - Linne, Marja-Leena N1 - jufoid=55187 INT=mat,"Lehtimäki, Mikko" PY - 2017/7/1 Y1 - 2017/7/1 N2 - In this study a nonlinear mathematical model of plasticity in the brain is reduced using the Proper Orthogonal Decomposition and Discrete Empirical Interpolation Method. Such methods are remarkably useful for connecting reduced small scale models via the inputs and outputs to form optimally performing large scale models. Novel results were obtained as mathematical model order reduction has not been applied in neuroscience without linearization of the mathematical model and never to the model presented here. The reduced order model consumes considerably less computational resources than the original while maintaining a low root mean square error between the original and reduced model. AB - In this study a nonlinear mathematical model of plasticity in the brain is reduced using the Proper Orthogonal Decomposition and Discrete Empirical Interpolation Method. Such methods are remarkably useful for connecting reduced small scale models via the inputs and outputs to form optimally performing large scale models. Novel results were obtained as mathematical model order reduction has not been applied in neuroscience without linearization of the mathematical model and never to the model presented here. The reduced order model consumes considerably less computational resources than the original while maintaining a low root mean square error between the original and reduced model. KW - cell signaling KW - Discrete Empirical Interpolation Method KW - model reduction KW - nonlinear models KW - Proper Orthogonal Decomposition KW - synaptic plasticity U2 - 10.1016/j.ifacol.2017.08.1143 DO - 10.1016/j.ifacol.2017.08.1143 M3 - Conference contribution T3 - IFAC-PapersOnLine SP - 7687 EP - 7692 BT - 20th IFAC World Congress PB - IFAC ER - TY - GEN T1 - Outlier-robust estimation of GPS satellite clock offsets AU - Martikainen, Simo AU - Piche, Robert AU - Ali-Löytty, Simo N1 - Artikkelissa ISBN-numero 978-1-4673-2343-7. ei ut-numeroa 22.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Electrical and Electronics Engineers IEEE PY - 2012 Y1 - 2012 N2 - A new method to predict a GPS satellite’s clock offset is presented. The motivation for this work is to improve the time to first fix and make the clock offset prediction less sensitive to outliers. The proposed method is tested with real data and it is shown to improve prediction accuracy compared to other known methods. AB - A new method to predict a GPS satellite’s clock offset is presented. The motivation for this work is to improve the time to first fix and make the clock offset prediction less sensitive to outliers. The proposed method is tested with real data and it is shown to improve prediction accuracy compared to other known methods. U2 - 10.1109/ICL-GNSS.2012.6253107 DO - 10.1109/ICL-GNSS.2012.6253107 M3 - Conference contribution SN - 978-1-4673-2344-4 T3 - 2012 International Conference on Localization and GNSS SP - 5 pp. BT - 2012 International Conference on Localization and GNSS ICL-GNSS, June 25-27, 2012, Starnberg, Germany PB - Institute of Electrical and Electronics Engineers IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Output Regulation for General Infinite-Dimensional Exosystems AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - ei ut-numeroa 27.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: International Federation of Automatic Control IFAC PY - 2012 Y1 - 2012 U2 - 10.3182/20120620-3-DK-2025.00113 DO - 10.3182/20120620-3-DK-2025.00113 M3 - Conference contribution SN - 978-3-902823-03-8 T3 - IFAC Symposium on Robust Control Design SP - 162 EP - 167 BT - Proceedings of the 7th IFAC Symposium on Robust Control Design, Rocond 2012, 20-22 June 2012, Aalborg, Denmark PB - International Federation of Automatic Control IFAC CY - Laxenburg, Austria ER - TY - GEN T1 - Output regulation of distributed parameter systems with time-periodic exosystems AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Conference contribution SN - 978-963-311-370-7 SP - 1637 EP - 1644 BT - Proceedings of the 19th International Symposium on Mathematical Theory of Networks and Systems, Budapest, Hungary, July 5-9, 2010 A2 - Edelmayer, Andras ER - TY - GEN T1 - Output Regulation of Infinite-Dimensional Time-Delay Systems AU - Paunonen, Lassi PY - 2017/5 Y1 - 2017/5 N2 - We study output tracking and disturbance rejection for linear infinite-dimensional time-delay systems using dynamic error feedback controllers with state delays. The class of systems covers many partial differential equations with state, input, and output delays. As our main result we characterize the solvability of the control problem in terms of the solvability of the associated regulator equations. AB - We study output tracking and disturbance rejection for linear infinite-dimensional time-delay systems using dynamic error feedback controllers with state delays. The class of systems covers many partial differential equations with state, input, and output delays. As our main result we characterize the solvability of the control problem in terms of the solvability of the associated regulator equations. U2 - 10.23919/ACC.2017.7963438 DO - 10.23919/ACC.2017.7963438 M3 - Conference contribution T3 - Proceedings of the American Control Conference SP - 3189 EP - 3193 BT - American Control Conference (ACC), 2017 PB - IEEE ER - TY - GEN T1 - Output Regulation Theory for Distributed Parameter Systems with Unbounded Control and Observation AU - Paunonen, Lassi AU - Pohjolainen, Seppo N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: IEEE PY - 2013 Y1 - 2013 M3 - Conference contribution SN - 978-1-4673-5716-6 T3 - IEEE Conference on Decision and Control SP - 1083 EP - 1088 BT - 52nd IEEE Conference on Decision and Control, IEEE CDC 2013, December 10-13, 2013, Florence, Italy PB - IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Paraconsistent fuzzy logic - A review AU - Turunen, Esko N1 - Contribution: organisation=mat,FACT1=1 PY - 2010 Y1 - 2010 M3 - Conference contribution SP - 158 EP - 162 BT - Logic, Algebra and Truth Degrees 2010, Second Conference of the Working Group on Mathematical Fuzzy Logic, 7-11 September 2010, Prague, Czech Republic ER - TY - GEN T1 - Paradigm shift in innovation indicators - from analog to digital AU - Still, Kaisa AU - Huhtamäki, Jukka AU - Russell, Martha G. AU - Rubens, Neil N1 - ei ut-numeroa 30.8.2013

Contribution: organisation=mat,FACT1=1

Publisher name: International Society for Professional Innovation Management ISPIM PY - 2012 Y1 - 2012 M3 - Conference contribution SN - 978-952-265-317-8 T3 - ISPIM Innovation Symposium BT - Proceedings of the 5th ISPIM Innovation Forum, 9-12 December, 2012, Seoul, Korea PB - International Society for Professional Innovation Management ISPIM CY - Manchester, UK ER - TY - GEN T1 - Particle filter and smoother for indoor localization AU - Nurminen, Henri AU - Ristimäki, Anssi AU - Ali-Löytty, Simo AU - Piche, Robert N1 - to appear in IEEEXPLORE

Contribution: organisation=ase,FACT1=0.75

Contribution: organisation=mat,FACT2=0.25

Portfolio EDEND: 2013-11-29

Publisher name: IEEE PY - 2013 Y1 - 2013 N2 - We present a real-time particle filter for 2D and 3D hybrid indoor positioning. It uses wireless local area network (WLAN) based position measurements, step and turn detection from a hand-held inertial sensor unit, floor plan restrictions, altitude change measurements from barometer and possibly other measurements such as occasional GNSS fixes. We also present a particle smoother, which uses future measurements to improve the position estimate for non-real-time applications. A lightweight fallback filter is run in the background for initialization, divergence monitoring and possibly re-initialization. In real-data tests the particle filter is more accurate and consistent than the methods that do not use floor plans. An example is shown on how smoothing helps to improve the filter estimate. Moreover, a floor change case is presented, in which the filter is capable of detecting the floor change and improving the 2D accuracy using the floor change information. AB - We present a real-time particle filter for 2D and 3D hybrid indoor positioning. It uses wireless local area network (WLAN) based position measurements, step and turn detection from a hand-held inertial sensor unit, floor plan restrictions, altitude change measurements from barometer and possibly other measurements such as occasional GNSS fixes. We also present a particle smoother, which uses future measurements to improve the position estimate for non-real-time applications. A lightweight fallback filter is run in the background for initialization, divergence monitoring and possibly re-initialization. In real-data tests the particle filter is more accurate and consistent than the methods that do not use floor plans. An example is shown on how smoothing helps to improve the filter estimate. Moreover, a floor change case is presented, in which the filter is capable of detecting the floor change and improving the 2D accuracy using the floor change information. U2 - http://dx.doi.org/10.1109/IPIN.2013.6817903 DO - http://dx.doi.org/10.1109/IPIN.2013.6817903 M3 - Conference contribution T3 - International Conference on Indoor Positioning and Indoor Navigation SP - 137 EP - 146 BT - International Conference on Indoor Positioning and Indoor Navigation, IPIN 2013, 28-31 Oct 2013, Montbéliard-Belfort, France PB - IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Plotting root-locus of infinite-dimensional systems AU - Laakkonen, Petteri N1 - ei ut-numeroa 29.3.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 M3 - Conference contribution SN - 978-951-39-4331-8 T3 - CAO ECCOMAS Thematic Conference on Computational Analysis and Optimization SP - 139 EP - 142 BT - Proceedings of CAO2011 ECCOMAS Thematic Conference on Computational Analysis and Optimization, Jyväskylä, Finland, 9.6.-11.6.2011. Reports of the Department of Mathematical Information Technology. Series A Collections A2 - Repin, Sergey A2 - Tiihonen, Timo A2 - Tuovinen, Tero PB - University of Jyväskylä CY - Jyväskylä ER - TY - GEN T1 - Positioning with coverage area estimates generated from location fingerprints AU - Koski, Laura AU - Piche, Robert AU - Kaseva, Ville AU - Ali-Löytty, Simo AU - Hännikäinen, Marko N1 - yhteisjulkaisu tietokonetekniikka laitoksen kanssa

Contribution: organisation=mat,FACT1=0.5

Contribution: organisation=tkt,FACT2=0.5 PY - 2010 Y1 - 2010 U2 - 10.1109/WPNC.2010.5653409 DO - 10.1109/WPNC.2010.5653409 M3 - Conference contribution SN - 978-1-4244-7157-7 SP - 99 EP - 106 BT - Proceedings of the 7th Workshop on Positioning, Navigation and Communication 2010 WPNC'10, 11-12 March 2010, Dresden, Germany ER - TY - GEN T1 - Practical Partial Order Reduction for CSP AU - Gibson-Robinson, Thomas AU - Hansen, Henri AU - Roscoe, A. Willian AU - Wang, Xu PY - 2015 Y1 - 2015 N2 - FDR is an explicit-state refinement checker for the process algebra CSP and, as such, is vulnerable to the state-explosion problem. In this paper, we show how a form of partial-order reduction, an automatic state reduction mechanism, can be utilised to soundly reduce the number of states that must be visited. In particular, we develop a compositional method for partial-order reduction that takes advantage of FDR’s internal, compositional, process representation. Further, we develop novel methods of preserving the traces of a process which allow partial-order reduction to be applied to arbitrary FDR refinement checks. We also provide details on how to efficiently implement the algorithms required for partial-order reduction. AB - FDR is an explicit-state refinement checker for the process algebra CSP and, as such, is vulnerable to the state-explosion problem. In this paper, we show how a form of partial-order reduction, an automatic state reduction mechanism, can be utilised to soundly reduce the number of states that must be visited. In particular, we develop a compositional method for partial-order reduction that takes advantage of FDR’s internal, compositional, process representation. Further, we develop novel methods of preserving the traces of a process which allow partial-order reduction to be applied to arbitrary FDR refinement checks. We also provide details on how to efficiently implement the algorithms required for partial-order reduction. U2 - 10.1007/978-3-319-17524-9_14 DO - 10.1007/978-3-319-17524-9_14 M3 - Conference contribution SN - 978-3-319-17523-2 VL - 9058 T3 - Lecture Notes in Computer Science SP - 188 EP - 203 BT - Nasa Formal Methods PB - Springer International Publishing ER - TY - GEN T1 - Prime filters on residuated lattices AU - Kondo, Michiro AU - Turunen, Esko N1 - Contribution: organisation=mat,FACT1=1

Publisher name: Institute of Electrical and Electronics Engineers IEEE PY - 2012 Y1 - 2012 U2 - 10.1109/ISMVL.2012.40 DO - 10.1109/ISMVL.2012.40 M3 - Conference contribution SN - 978-0-7695-4673-5 T3 - IEEE International Symposium on Multiple-Valued Logic SP - 89 EP - 91 BT - 2012 IEEE 42nd International Symposium on Multiple-Valued Logic ISMVL, 14-16 May, 2012, Victoria, British Columbia, Canada PB - Institute of Electrical and Electronics Engineers IEEE CY - Piscataway, NJ ER - TY - GEN T1 - Process for Measuring and Visualizing an Open Innovation Platform: Case Demola AU - Huhtamäki, Jukka AU - Luotonen, Ville AU - Kairamo, Ville AU - Still, Kaisa AU - Russell, Martha G. N1 - Contribution: organisation=mat,FACT1=1

Portfolio EDEND: 2013-12-29

Publisher name: ACM PY - 2013 Y1 - 2013 N2 - Open innovation breaks the traditional pattern for developing new innovation leading to new business and the activities toward it. Consequently, new requirements are posed to innovation measurement. Demola is an open innovation platform that takes real-life problems from companies and other organizations and puts together and facilitates projects where students from different universities come together to solve the problems. This paper describes a set of network visualizations and animations that were developed in co-creation with the Demola operators to make visible the activity that Demola has initiated. Moreover, the development process used to design the visualizations and the technical process that was applied are described and discussed. We claim that static network visualizations and animations of an open innovation platform development are useful in presenting, describing, marketing and selling the platform for existing and new stakeholders. Our experience shows that in order to develop visualizations and animations that meet the requirements set by the different stakeholders, an iterative and incremental development process is needed. Moreover, we claim that taking a data-driven approach to visualization development is a key enabler in supporting the development. AB - Open innovation breaks the traditional pattern for developing new innovation leading to new business and the activities toward it. Consequently, new requirements are posed to innovation measurement. Demola is an open innovation platform that takes real-life problems from companies and other organizations and puts together and facilitates projects where students from different universities come together to solve the problems. This paper describes a set of network visualizations and animations that were developed in co-creation with the Demola operators to make visible the activity that Demola has initiated. Moreover, the development process used to design the visualizations and the technical process that was applied are described and discussed. We claim that static network visualizations and animations of an open innovation platform development are useful in presenting, describing, marketing and selling the platform for existing and new stakeholders. Our experience shows that in order to develop visualizations and animations that meet the requirements set by the different stakeholders, an iterative and incremental development process is needed. Moreover, we claim that taking a data-driven approach to visualization development is a key enabler in supporting the development. U2 - 10.1145/2523429.2523478 DO - 10.1145/2523429.2523478 M3 - Conference contribution SN - 978-1-4503-1992-8 T3 - MindTrek Conference SP - 166 EP - 171 BT - 17th International Academic MindTrek Conference, October 1-4, 2013, Tampere, Finland PB - ACM ER - TY - GEN T1 - Projection-based order reduction of a nonlinear biophysical neuronal network model AU - Lehtimäki, Mikko AU - Paunonen, Lassi AU - Linne, Marja-Leena N1 - JUFOID=57317 PY - 2019 Y1 - 2019 N2 - In this study mathematical model order reduction is applied to a nonlinear model of a network of biophysically realistic heterogeneous neurons. The neuron model describes a pyramidal cell in the hippocampal CA3 area of the brain and includes a state-triggered jump condition. The network displays synchronized firing of action potentials (spikes), a fundamental phenomenon of sensory information processing in the brain. Simulation of the system is computationally expensive, which limits network size and hence biological realism. We reduce the network using advanced variations of Proper Orthogonal Decomposition and Discrete Empirical Interpolation Method. The reduced models should recreate the original spiking activity. We show that reduction methods with online adaptivity achieve the most accurate reduction results. Some of the reduced models consume less computational resources than the original, at the cost of changes in population activity of the tested network model. AB - In this study mathematical model order reduction is applied to a nonlinear model of a network of biophysically realistic heterogeneous neurons. The neuron model describes a pyramidal cell in the hippocampal CA3 area of the brain and includes a state-triggered jump condition. The network displays synchronized firing of action potentials (spikes), a fundamental phenomenon of sensory information processing in the brain. Simulation of the system is computationally expensive, which limits network size and hence biological realism. We reduce the network using advanced variations of Proper Orthogonal Decomposition and Discrete Empirical Interpolation Method. The reduced models should recreate the original spiking activity. We show that reduction methods with online adaptivity achieve the most accurate reduction results. Some of the reduced models consume less computational resources than the original, at the cost of changes in population activity of the tested network model. KW - Neuroscience KW - Control theory KW - Model reduction U2 - 10.1109/CDC40024.2019.9029510 DO - 10.1109/CDC40024.2019.9029510 M3 - Conference contribution SN - 978-1-7281-1399-9 T3 - IEEE Conference on Decision & Control BT - 2019 IEEE 58th Conference on Decision and Control (CDC) PB - IEEE ER - TY - GEN T1 - Projektityöskentely matematiikan opiskelussa yläkoululaisten ja heidän opettajiensa kokemana AU - Viro, Elina AU - Joutsenlahti, Jorma AU - Eriksson, Sirkka-Liisa N1 - EXT=”Eriksson, Sirkka-Liisa” PY - 2017/10/31 Y1 - 2017/10/31 N2 - Projektioppiminen on ongelmakeskeinen menetelmä, jossa tavoitteena on oppiaineen sisältöjen syvällisen ymmärryksen lisäksi työelämätaitojen harjoittelu. Opetus pyrkii yhdistämään opiskeltavan aineen oppilaiden jokapäiväiseen elämään tai tulevaan työelämään. Tässä tutkimuksessa tarkastelemme oppilaiden (N = 201) ja opettajien (N = 10) kokemuksia projektityöskentelystä yläkoulun matematiikan tunneilla. Projektit tukivat oppilaiden ymmärrystä siitä, missä matematiikkaa tarvitaan koulun ulkopuolella ja motivoivat erityisesti poikia matematiikan opiskeluun. AB - Projektioppiminen on ongelmakeskeinen menetelmä, jossa tavoitteena on oppiaineen sisältöjen syvällisen ymmärryksen lisäksi työelämätaitojen harjoittelu. Opetus pyrkii yhdistämään opiskeltavan aineen oppilaiden jokapäiväiseen elämään tai tulevaan työelämään. Tässä tutkimuksessa tarkastelemme oppilaiden (N = 201) ja opettajien (N = 10) kokemuksia projektityöskentelystä yläkoulun matematiikan tunneilla. Projektit tukivat oppilaiden ymmärrystä siitä, missä matematiikkaa tarvitaan koulun ulkopuolella ja motivoivat erityisesti poikia matematiikan opiskeluun. M3 - Conference contribution T3 - Proceedings of the FMSERA annual symposium BT - 2017: Proceedings of the annual FMSERA symposium 2016 ER - TY - GEN T1 - Rank Based Fingerprinting Algorithm for Indoor Positioning AU - Machaj, Juraj AU - Brida, Peter AU - Piche, Robert N1 - ei ut-numeroa 5.4.2014

Contribution: organisation=mat,FACT1=1 PY - 2011 Y1 - 2011 N2 - This paper describes a novel RSS rank based fingerprinting algorithm for indoor positioning. Because RSS rank is invariant to bias and scaling, the algorithm provides the same accuracy for any receiver device, without the need for calibration. Similarity metrics to compare ranked vectors are introduced and their impact on positioning accuracy is investigated in experiments. Experimental results shown that the algorithm can achieve better accuracy than some commonly used fingerprinting algorithms. AB - This paper describes a novel RSS rank based fingerprinting algorithm for indoor positioning. Because RSS rank is invariant to bias and scaling, the algorithm provides the same accuracy for any receiver device, without the need for calibration. Similarity metrics to compare ranked vectors are introduced and their impact on positioning accuracy is investigated in experiments. Experimental results shown that the algorithm can achieve better accuracy than some commonly used fingerprinting algorithms. U2 - 10.1109/IPIN.2011.6071929 DO - 10.1109/IPIN.2011.6071929 M3 - Conference contribution SN - 978-1-4577-1805-2 T3 - International Conference on Indoor Positioning and Indoor Navigation IPIN SP - 1 EP - 6 BT - 2011 International Conference on Indoor Positioning and Indoor Navigation IPIN, 21-23 September 2011, Guimarães, Portugal PB - IEEE CY - Piscataway, NJ ER -