Resolution and contrast in terahertz pulse time-domain holographic reconstruction

Here, we present a comprehensive study of the reconstruction quality in terahertz (THz) pulse time-domain holography. We look into single wavelength reconstructions, as well as broadband recovery enabled by the ultrabroadband nature of radiation and coherent detection enabled by electro-optic or photoconductive sensing. We demonstrate the transverse resolution dependence for amplitude and phase objects on the solid angle of the inline recorded time-domain THz hologram, and then turn to the contrast of reconstructed binary amplitude objects, and further to longitudinal resolution of phase objects. We show that transverse resolution can reach values comparable to the wavelength of the radiation used, and longitudinally, phase objects can be resolved with even greater precision. We compare the obtained resolution with theoretical estimates and show that THz pulse time-domain holography is a powerful non-contact imaging tool.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computing Sciences, ITMO University, University of Birmingham
Contributors: Turov, A. T., Kulya, M. S., Petrov, N. V., Gorodetsky, A.
Pages: G231-G240
Publication date: 1 Dec 2019
Peer-reviewed: Yes

Publication information

Journal: Applied Optics
Volume: 58
Issue number: 34
ISSN (Print): 1559-128X
Original language: English
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics, Engineering (miscellaneous), Electrical and Electronic Engineering
Source: Scopus
Source ID: 85075600417

Research output: Contribution to journalArticleScientificpeer-review

Terahertz pulse time-domain holography with balance detection: Complex-domain sparse imaging

We investigated the peculiarities of the terahertz pulse time-domain holography principle in the case of raster scanning with the balance detection system. The noise in this system represents a Skellam distribution model, which differentiates it from systems based on a photoconductive antenna. We analyzed this Skellam model and provided both numerical and experimental investigations. We found that the variance of the noise in the balance detection system does not depend on the true signal. Complex-domain images obtained in this model are filtered by block-matching algorithms adapted for spatio-temporal and spatiospectral volumetric data. We presented a new cube complex-domain filter algorithm that uses block matching in all 3D data sets simultaneously in spatial and frequency coordinates. A combination of temporal and complex-domain filters allows us to expand the dynamic range of terahertz frequencies for which we can obtain amplitude/phase information. Experimental data demonstrate an improvement in the quality of the resultant images both in the time domain and complex-spectral domain. The simulation and experimental results are in good agreement.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Computing Sciences, Research group: Computational Imaging-CI, ITMO University
Contributors: Kulya, M., Petrov, N. V., Katkovnik, V., Egiazarian, K.
Pages: G61-G70
Publication date: 1 Dec 2019
Peer-reviewed: Yes

Publication information

Journal: Applied Optics
Volume: 58
Issue number: 34
ISSN (Print): 1559-128X
Original language: English
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics, Engineering (miscellaneous), Electrical and Electronic Engineering
Source: Scopus
Source ID: 85075613421

Research output: Contribution to journalArticleScientificpeer-review

Measuring stem diameters with TLS in boreal forests by complementary fitting procedure

Point clouds generated by terrestrial laser scanners (TLS) have enabled new ways to measure stem diameters. A common method for diameter calculation is to fit cylindrical or circular shapes into the TLS point cloud, which can be based either on a single scan or a co-registered combination of several scans. However, as various defects in the point cloud may affect the final diameter results, we propose an automatized processing chain which takes advantage of complementing steps. Processing consists of two fitting phases and an additional taper curve calculation to define the final diameter measurements. First, stems are detected from co-registered data of several scans using surface normals and cylinder fitting. This provides a robust framework for localizing the stems and estimating diameters at various heights. Then, guided by the cylinders and their indicative diameters, another fitting round is performed by cutting the stems into thin horizontal slices and reassessing their diameters by circular shape. For each slice, the quality of the cylinder-modelled diameter is evaluated first with co-registered data and if it is found to be deficient, potentially due to modelling defects or co-registration errors, diameter is detected through single scans. Finally, slice diameters are applied to construct a spline-based taper curve model for each tree, which is used to calculate the final stem dimensions. This methodology was tested in southern Finland using a set of 505 trees. At the breast height level (1.3 m), the results indicate 5.2 mm mean difference (3.2%), −0.4 mm bias (-0.3%) and 7.3 mm root mean squared error (4.4%) to reference measurements, and at the height of 6.0 m, respective values are 6.5 mm (3.6%), +1.6 mm (0.9%) and 8.4 mm (4.8%). These values are smaller compared to most of the corresponding contemporary studies, and outperform the initial cylinder models. This indicates that the applied processing chain is capable of producing relatively accurate diameter measurements, which can, at the cost of computational heaviness, remove various defects and improve the modelling results.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Mathematics, Natural Resources Institute Finland (Luke)
Contributors: Pitkänen, T. P., Raumonen, P., Kangas, A.
Number of pages: 13
Pages: 294-306
Publication date: 2019
Peer-reviewed: Yes
Early online date: 8 Dec 2018

Publication information

Journal: ISPRS Journal of Photogrammetry and Remote Sensing
Volume: 147
ISSN (Print): 0924-2716
Original language: English
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics, Engineering (miscellaneous), Computer Science Applications, Computers in Earth Sciences
Keywords: Circle fitting, Cylinder fitting, Stem extraction, Taper curve, Terrestrial laser scanning
Electronic versions: 
Source: Scopus
Source ID: 85057752987

Research output: Contribution to journalArticleScientificpeer-review

Social capital characteristics in RD project networks

Network research has multiple approaches that offer knowledge related to multiple network types. This article identifies and discusses social capital characteristics in the context of government-funded RD project networks. Previous literature on this context has typically focused on collaboration between universities and firms while our interest is solely on interfirm relationships. Secondly, the previous literature on interfirm collaboration concerns typically other types of networks such as strategic alliances. We argue, that to understand the dynamics of inter firm collaboration in RD project networks, the research needs to be conducted in coherent environment. Data for this qualitative research was collected by interviewing 18 firm representatives who had experience on participating government-funded RD projects. We recognized social capital characteristics in RD projects and organized these findings under structural, cognitive and relational dimensions of social capital. Results indicate that project networks' social capital characteristics differ in many parts from strategic alliances and thus support our argument. The results can be exploited by project coordinators, innovation officers and project network members to facilitate the interfirm collaboration in RD project networks.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Mechanical Engineering and Industrial Systems, Research area: Manufacturing and Automation
Contributors: Majuri, M., Lanz, M.
Publication date: 4 Oct 2018

Host publication information

Title of host publication: 2018 Portland International Conference on Management of Engineering and Technology (PICMET)
Publisher: IEEE
Article number: 8481775
ISBN (Electronic): 9781890843373
ASJC Scopus subject areas: Strategy and Management, Communication, Engineering (miscellaneous), Management of Technology and Innovation, Organizational Behavior and Human Resource Management, Computer Networks and Communications, Decision Sciences (miscellaneous)

Bibliographical note

jufoid=9093

Source: Scopus
Source ID: 85056486979

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Focus model for metric depth estimation in standard plenoptic cameras

In recent years, a lot of efforts have been devoted to the problem of depth estimation from lightfield images captured by standard plenoptic cameras. However, most of the metric depth estimation methods in the state-of-the-art leverage pixel disparity only. In this paper, we tackle the problem of focus-based metric depth estimation in standard plenoptic cameras. For this purpose we propose a closed-form model that relates the refocusing parameter with the focus distance of a plenoptic camera in order to allow for metric depth estimation. Based on the proposed model, we develop a calibration procedure that allows finding the parameters of the model. Using measurements of a time-of-flight sensor as ground-truth, experimental validation in a distance range of 0.2–1.6 m shows that focus-based depth estimation is feasible with a root-mean-squared error of less than 5 cm.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Signal Processing, Universidad Industrial de Santander, Universidad Antonio Nariño
Contributors: Pertuz, S., Pulido-Herrera, E., Kämäräinen, J.
Number of pages: 10
Pages: 38-47
Publication date: 1 Oct 2018
Peer-reviewed: Yes

Publication information

Journal: ISPRS Journal of Photogrammetry and Remote Sensing
Volume: 144
ISSN (Print): 0924-2716
Ratings: 
  • Scopus rating (2018): CiteScore 8.64 SJR 2.979 SNIP 2.862
Original language: English
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics, Engineering (miscellaneous), Computer Science Applications, Computers in Earth Sciences
Keywords: Calibration, Depth estimation, Focus, Lightfield, Plenoptic camera
Source: Scopus
Source ID: 85049523458

Research output: Contribution to journalArticleScientificpeer-review

A Consequence of AI on Engineering Education: Growing Demand for Deeper Understanding

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Electrical Energy Engineering, Tampere University of Applied Sciences
Contributors: Korpela, A., Mikkonen, R.
Pages: 244-252
Publication date: 17 Sep 2018

Host publication information

Title of host publication: Proceedings of the SEFI annual conference 17-22 September 2018
Place of publication: Copenhagen
Publisher: European Society for Engineering Education SEFI
Editors: Clark, R., Hussmann, P., Järvinen, H., Murphy, M., Vigild, M.
ISBN (Electronic): 978-2-87352-016-8
ASJC Scopus subject areas: Engineering (miscellaneous)

Bibliographical note

EXT="Korpela, A."

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Industrial impact on courses in software enginering: an empirical study on contents of software engineering courses in 1990-2016

Development of the curriculum is based on academic knowledge and research, but there are often topics where the industrial impact is clearly present. Developers of curricula should keep the contents up-to-date, both in the academic and professional points of view; especially in software engineering, where much of the experiences come from the companies. Institutions like ACM are making regular model curricula to help in the development process, but they are often a little bit delayed when compared with actively developed curricula.
In this paper, we have three points of view. The first one, based on material collected for paper [1], discusses the topics of master's theses, or how the topics have changed during the time. The second one studies the changes made for the offered courses, and we like to see if changes in the master's topics and courses have any connection. The third viewpoint is a short note how the ACM model curriculum of software engineering has changed at the same time.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Pervasive Computing
Contributors: Järvinen, H.
Number of pages: 8
Pages: 928-935
Publication date: 17 Sep 2018

Host publication information

Title of host publication: Proceedings of the SEFI annual conference 17-22 September 2018
Place of publication: Copenhagen
Publisher: European Society for Engineering Education SEFI
Editors: Clark, R., Hussmann, P., Järvinen, H., Murphy, M., Vigild, M.
ISBN (Electronic): 978-2-87352-016-8

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Restoration of low-dose digital breast tomosynthesis

In breast cancer screening, the radiation dose must be kept to the minimum necessary to achieve the desired diagnostic objective, thus minimizing risks associated with cancer induction. However, decreasing the radiation dose also degrades the image quality. In this work we restore digital breast tomosynthesis (DBT) projections acquired at low radiation doses with the goal of achieving a quality comparable to that obtained from current standard full-dose imaging protocols. A multiframe denoising algorithm was applied to low-dose projections, which are filtered jointly. Furthermore, a weighted average was used to inject a varying portion of the noisy signal back into the denoised one, in order to attain a signal-to-noise ratio comparable to that of standard full-dose projections. The entire restoration framework leverages a signal-dependent noise model with quantum gain which varies both upon the projection angle and on the pixel position. A clinical DBT system and a 3D anthropomorphic breast phantom were used to validate the proposed method, both on DBT projections and slices from the 3D reconstructed volume. The framework is shown to attain the standard full-dose image quality from data acquired at 50% lower radiation dose, whereas progressive loss of relevant details compromises the image quality if the dosage is further decreased.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Signal Processing, University of São Paulo, Noiseless Imaging Ltd, University of Pennsylvania
Contributors: Borges, L. R., Azzari, L., Bakic, P. R., Maidment, A. D., Vieira, M. A., Foi, A.
Publication date: 19 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Measurement Science and Technology
Volume: 29
Issue number: 6
Article number: 064003
ISSN (Print): 0957-0233
Ratings: 
  • Scopus rating (2018): CiteScore 2.21 SJR 0.57 SNIP 1.243
Original language: English
ASJC Scopus subject areas: Instrumentation, Engineering (miscellaneous), Applied Mathematics
Keywords: denoising, digital breast tomosynthesis, dose reduction, variance stabilization
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 85047322570

Research output: Contribution to journalArticleScientificpeer-review

A multi-agent approach for processing industrial enterprise data

The C2NET project aims to provide cloud-based platform for the supply chain interactions. The architecture of such platform includes a Data Collection Framework (DCF) for managing the collection of the company's data. The DCF collects, transforms and stores data from both Internet of Things (IoT) devices in the factory shopfloor and company enterprises data via two types of hub; Legacy system hub (LSH) and IoT hub. Since the C2NET, targets the Small and Medium-sized Enterprises (SMEs), the enterprise data, or legacy data as called in the C2NET project, can be provided via excel files. Thus, this research work highlights a technique for processing the excel files in the LSHs. This technique adopts the concept of Multi-Agent Systems for processing the data as table in the excel files in the LSH. The multi-agent approach allows the LSH to process any excel file regardless the complexity in the data structure or in the file table. Furthermore, the presented approach enhances the processing of the excel files in different aspects, such as the size of the excel file or the required processing power.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Automation and Hydraulic Engineering, Research group: Automation and Systems Theory, Universitat Politècnica de València, Instituto de Desenvolvimento de Novas Tecnologias
Contributors: Mohammed, W. M., Ferrer, B. R., Martinez, J. L., Sanchis, R., Andres, B., Agostinho, C.
Number of pages: 7
Pages: 1209-1215
Publication date: 2 Feb 2018

Host publication information

Title of host publication: 2017 International Conference on Engineering, Technology and Innovation : Engineering, Technology and Innovation Management Beyond 2020: New Challenges, New Approaches, ICE/ITMC 2017 - Proceedings
Publisher: IEEE
ISBN (Electronic): 9781538607749
ASJC Scopus subject areas: Computer Science Applications, Software, Engineering (miscellaneous), Computer Networks and Communications
Keywords: Cloud Based, Data Collection, Enterprise, Multi-Agent Systems, supply Chain
Source: Scopus
Source ID: 85047492606

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

An approach to production scheduling optimization a case of an oil lubrication and hydraulic systems manufacturer

Cloud-enabled tools developed in the Cloud Collaborative Manufacturing Networks (C2NET) project address the needs of small and medium enterprises with respect to information exchange and visibility across the collaboration partners in the supply network, coupled with automated and collaborative production planning and supply management. This paper analyses a case of an oil lubrication and hydraulic systems manufacturer and describes a pilot application of C2NET where the production schedule is optimized according to the priorities of the pilot company. In this case the goal is a highly adaptive just-in-time manufacturing schedule with guaranteed on time delivery.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Automation and Hydraulic Engineering, VTT Technical Research Centre of Finland, Roberto Camp Fluidhouse Ltd.
Contributors: Katasonov, A., Lastusilta, T., Korvola, T., Saari, L., Bendas, D., Mohammed, W. M., Lee, A. N.
Number of pages: 8
Pages: 1123-1130
Publication date: 2 Feb 2018

Host publication information

Title of host publication: 2017 International Conference on Engineering, Technology and Innovation : Engineering, Technology and Innovation Management Beyond 2020: New Challenges, New Approaches, ICE/ITMC 2017 - Proceedings
Publisher: IEEE
ISBN (Electronic): 9781538607749
ASJC Scopus subject areas: Computer Science Applications, Software, Engineering (miscellaneous), Computer Networks and Communications
Keywords: cloud-supported manufacturing, enterprise collaboration, information exchange, just-in-time manufacturing, Mixed-Integer Linear Programming, on time delivery, optimization, production scheduling, Small and Medium size Enterprise, supply network
Source: Scopus
Source ID: 85047524893

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Configuring and visualizing the data resources in a cloud-based data collection framework

The Manufacturing Enterprise Solutions Association (MESA) provided the abstract and general definition of the Manufacturing Execution Systems (MES). A dedicated function has been reserved for the data collection activities. In this matter, the Cloud Collaborative Manufacturing Networks (C2NET) project tends to provide a cloud based platform for hosting the interactions of the supply chain in a collaborative network. Within the architecture of the C2NET project, a Data Collection Framework (DCF) is designed to fulfill the function of data collection. This allows the companies to provide their data, which can be both enterprise and Internet of Things (IoT) devices type of data to the platform for further use. The collection of the data is achieved by a specific third party application, i.e., the Legacy System Hub (LSH). This research work presents the approach of configuring and visualizing the data resources in the C2NET platform. This approach employs the web-based applications and the help of the LSH. This permits the C2NET platform to adapt to any kind of third party application, which manipulates enterprise data, following the generic and flexible solution of this approach.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Automation and Hydraulic Engineering, Research group: Automation and Systems Theory, Instituto de Desenvolvimento de Novas Tecnologias
Contributors: Mohammed, W. M., Ferrer, B. R., Jose, L., Lastra, M., Aleixo, D., Agostinho, C.
Number of pages: 8
Pages: 1201-1208
Publication date: 2 Feb 2018

Host publication information

Title of host publication: 2017 International Conference on Engineering, Technology and Innovation : Engineering, Technology and Innovation Management Beyond 2020: New Challenges, New Approaches, ICE/ITMC 2017 - Proceedings
Publisher: IEEE
ISBN (Electronic): 9781538607749
ASJC Scopus subject areas: Computer Science Applications, Software, Engineering (miscellaneous), Computer Networks and Communications
Keywords: Cloud Based, Data Collection, Data Resources, Supply Chain, Visualization

Bibliographical note

INT=aut,"Jose, L."

Source: Scopus
Source ID: 85047476305

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Exploiting suppliers' potential in construction innovations

There is a need to understand ways to enhance innovations in the construction industry. It is argued that suppliers have potential to develop new innovations, but they are largely neglected in earlier construction-related research. This research focuses on suppliers' role in construction innovations, and the aim of the research is to increase understanding of practices for exploiting suppliers' potential in that context. A qualitative, explanatory research strategy is employed in the context of construction industry in Finland. Eighteen interviews are conducted with contractors to discover experiences and practices related to suppliers' potential in construction innovations. The results reveal practices for exploiting supplier's potential in construction innovations. As a key contribution, the research shows that suppliers have an important role in construction innovation but exploitation of suppliers' potential is still rather underdeveloped.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Research group: Center for Research on Operations Projects and Services, Industrial and Information Management
Contributors: Sariola, R.
Number of pages: 7
Pages: 678-684
Publication date: 2 Feb 2018

Host publication information

Title of host publication: 2017 International Conference on Engineering, Technology and Innovation : Engineering, Technology and Innovation Management Beyond 2020: New Challenges, New Approaches, ICE/ITMC 2017 - Proceedings
Publisher: IEEE
ISBN (Electronic): 9781538607749
ASJC Scopus subject areas: Computer Science Applications, Software, Engineering (miscellaneous), Computer Networks and Communications
Keywords: construction innovation, project networks, supplier management
Source: Scopus
Source ID: 85047528988

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Analysis of outdoor and indoor propagation at 15 GHz and millimeter wave frequencies in microcellular environment

The main target of this article is to perform the multidimensional analysis of multipath propagation in an indoor and outdoor environment at higher frequencies i.e. 15 GHz, 28 GHz and 60 GHz, using “sAGA” a 3D ray tracing tool. A real world outdoor Line of Sight (LOS) microcellular environment from the Yokusuka city of Japan is considered for the analysis. The simulation data acquired from the 3D ray tracing tool includes the received signal strength, power angular spectrum and the power delay profile. The different propagation mechanisms were closely analyzed. The simulation results show the difference of propagation in indoor and outdoor environment at higher frequencies and draw a special attention on the impact of diffuse scattering at 28 GHz and 60 GHz. In a simple outdoor microcellular environment with a valid LOS link between the transmitter and a receiver, the mean received signal at 28 GHz and 60 GHz was found around 5.7 dB and 13 dB inferior in comparison with signal level at 15 GHz. Whereas the difference in received signal levels at higher frequencies were further extended in an indoor environment due to higher building penetration loss. However, the propagation and penetration loss at higher frequency can be compensated by using the antenna with narrow beamwidth and larger gain.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Laboratory of Radio Network Planning, Research group: Wireless Communications and Positioning
Contributors: Sheikh, M. U., Lempiainen, J.
Number of pages: 8
Pages: 160-167
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Advances in Science, Technology and Engineering Systems
Volume: 3
Issue number: 1
ISSN (Print): 2415-6698
Original language: English
ASJC Scopus subject areas: Engineering (miscellaneous), Management of Technology and Innovation, Physics and Astronomy (miscellaneous)
Keywords: 3D ray tracing, 5G, Microcellular, Millimeter wave frequencies, Multipath propagation, System performance
Source: Scopus
Source ID: 85061718805

Research output: Contribution to journalArticleScientificpeer-review

Bringing stimulated ideation in a web environment: Students’ evaluations of a basic software release

Previous studies have demonstrated that creative design activities benefit from stimuli and that textual prompts might extend the exploration of the design space. However, the number of stimuli to conduct a wide exploration is large and the support of an ICT platform results necessary to manage a creative task effectively because of the presumably large number of generated ideas. Within a project named Startled, a very simple first release of a web application has been developed that supports ideation activities by means of stimuli. Dozens of students enrolled in different courses and Universities have tested the platform and answered a questionnaire, which aimed to elucidate their self-efficacy, perceived workload, ease of use and utility of the present version of the web application. The outcomes show, beyond few differences between students with diverse backgrounds, a majority of neutral and slightly positive answers. The results are not fully satisfying and the authors intend to make the ICT-supported creative tool more guided, user-friendly and intuitive.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Computing Sciences, Free University of Bolzano-Bozen, CNR-INO
Contributors: Borgianni, Y., Lenarduzzi, V., Rotini, F., Taibi, D.
Publication date: 2018

Host publication information

Title of host publication: ICDC 2018 - 5th International Conference on Design Creativity, Conference Proceedings
Publisher: DESIGN SOCIETY
Editors: Dekoninck, E., Wodehouse, A., Snider, C., Georgiev, G., Cascini, G.
ISBN (Electronic): 9781904670834

Publication series

Name: Proceedings of the International Conference on Engineering Design, ICED
ISSN (Print): 2220-4334
ISSN (Electronic): 2220-4342
ASJC Scopus subject areas: Engineering (miscellaneous), Industrial and Manufacturing Engineering, Modelling and Simulation
Keywords: New product benefits, Questionnaires, Stimulated ideation, Web application
Source: Scopus
Source ID: 85072785974

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Enhanced outdoor to indoor propagation models and impact of different ray tracing approaches at higher frequencies

The main target of this article is to study the provision of indoor service (coverage) using outdoor base station at higher frequencies i.e. 10 GHz, 30 GHz and 60 GHz. In an outdoor to indoor propagation, an angular wall loss model is used in the General Building Penetration (GBP) model for estimating the additional loss at the intercept point of the building exterior wall. A novel angular wall loss model based on a separate incidence angle in azimuth and elevation plane is proposed in this paper. In the second part of this study, an Extended Building Penetration (EBP) model is proposed, and the performance of EBP model is compared with the GBP model. In EBP model, the additional fifth path known as the “Direct path” is proposed to be included in the GBP model. Based on the evaluation results, the impact of the direct path is found significant for the indoor users having the same or closed by height as that of the height of the transmitter. For the indoor users located far away from the exterior wall of building, a modified and enhanced approach of ray tracing type is proposed in this article. In the light of acquired simulation results, the impact of a modified ray tracing approach is emphasized.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Electrical Engineering, Research group: Laboratory of Radio Network Planning, Research group: Wireless Communications and Positioning, Ericsson Research
Contributors: Sheikh, M. U., Hiltunen, K., Lempiainen, J.
Number of pages: 11
Pages: 58-68
Publication date: 2018
Peer-reviewed: Yes

Publication information

Journal: Advances in Science, Technology and Engineering Systems
Volume: 3
Issue number: 2
ISSN (Print): 2415-6698
Original language: English
ASJC Scopus subject areas: Engineering (miscellaneous), Management of Technology and Innovation, Physics and Astronomy (miscellaneous)
Keywords: Angular loss, Building penetration loss, Outdoor to indoor, Propagation, Ray tracing, Wall loss model
Source: Scopus
Source ID: 85061801748

Research output: Contribution to journalArticleScientificpeer-review

Reliability of ACA interconnections on microvia HDI PCBs in thermal cycling conditions

New packaging technologies require new high density substrates. In built up high density interconnect (HDI) printed circuit boards (PCB) high density is achieved by using built up microvia layers. Such HDI PCBs may be used in many applications. In flip chip technology a bare chip is attached directly to a substrate which enables very high density and requires often also HDI PCBs. Anisotropic conductive adhesives (ACA) are especially well suited interconnection materials for high density flip chip applications. In this study the reliability of flip chip ACA attachments on several different HDI PCBs was studied. The PCBs had similar core layers, but the microvia layers of the PCBs were different. Test chips were attached on these PCBs using an ACA film (ACF). The reliability of the interconnections was tested using fast thermal cycling between the temperatures of -40?C and 125?C. Several failures were seen with all PCB materials during the 2,000 cycles of testing. The differences in the reliability of the different microvia layers were found to be relatively small and the microvia layer composition did not seem to be critical for the thermal cycling reliability of the ACF interconnections.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Department of Electrical Engineering, Research area: Reliability
Contributors: Frisk, L., Lahokallio, S., Kiilunen, J.
Publication date: 5 Jun 2016

Host publication information

Title of host publication: IMAPS Nordic Annual Conference 2016 Proceedings
Publisher: IMAPS-International Microelectronics and Packaging Society
Editor: Kutilainen, J.
ISBN (Electronic): 9781510827226
ASJC Scopus subject areas: Electrical and Electronic Engineering, Engineering (miscellaneous), Electronic, Optical and Magnetic Materials
Keywords: Anisotropic conductive adhesive, Flip chip, High density interconnect, Printed circuit board, Reliability, Thermal cycling
Source: Scopus
Source ID: 84988001295

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Correlation of wear and work in dual pivoted jaw crusher tests

A laboratory sized jaw crusher with uniform movement of the jaws, the Dual Pivoted Jaw Crusher (DPJC), was used to determine the relationship between wear and work. Wear was concentrated on the jaw plates opposing each other and was measured as mass loss of the specimens. Work was measured directly from the force and the displacement of the instrumented jaw, which allowed work to accumulate only from the actual crushing events. The tests were conducted with several jaw geometries and with two motional settings, where the relation of compressive and sliding motion between the jaws was varied.
The comminution of rock is presumed to be irreversible, meaning that the energy used for crack formation in the rock particles eventually results in the fracture of the particles. Therefore, the amount of energy needed to comminute rock particles should be roughly constant and not dependent on the loading conditions, if the speed of the loading contact is not changed. The DPJC test method allows the separation of work components into comminution specific work and sliding specific work. The results can be used to compare the crushability of minerals without the influence of the used test geometry or the selected jaw plate materials. The sliding work can be used for the comparison of the wear of the jaw plate materials

General information

Publication status: Published
MoE publication type: D3 Professional conference proceedings
Organisations: Materials Science, Research group: Materials Characterization, Research group: Materials Characterization, Metso Minerals, Inc.
Contributors: Terva, J., Valtonen, K., Siitonen, P., Kuokkala, V.
Publication date: Jun 2016

Host publication information

Title of host publication: The 17th Nordic Symposium on Tribology - NORDTRIB 2016
ASJC Scopus subject areas: Materials Science(all), Engineering (miscellaneous), Energy (miscellaneous)
Keywords: Jaw crusher, Comminution, Work, Wear, Abrasive wear
Electronic versions: 

Research output: Chapter in Book/Report/Conference proceedingConference contributionProfessional

Fracture Characteristics of High-Velocity Suspension Flame-Sprayed Aluminum Oxide Coatings

General information

Publication status: Published
MoE publication type: B3 Non-refereed article in conference proceedings
Organisations: Department of Materials Science, Research group: Surface Engineering, Research group: Materials Characterization, University of Stuttgart
Contributors: Kiilakoski, J., Lutoschkin, A., Plachetta, M., Apostol, M., Koivuluoto, H., Killinger, A., Vuoristo, P.
Number of pages: 6
Pages: 466-471
Publication date: 2016

Host publication information

Title of host publication: International Thermal Spray Conference & Exposition, ITSC 2016
Publisher: DVS Media GmbH
ISBN (Electronic): 978-3-87155-574-9
ASJC Scopus subject areas: Surfaces, Coatings and Films, Engineering (miscellaneous)
Keywords: ALUMINA COATINGS, HVOF spraying, Thermal spray coating, Bending test, Fracture

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientific

The effects of microstructure on erosive-abrasive wear behavior of carbide free bainitic and boron steels

The wear resistance of carbide free bainitic (CFB) microstructures have shown to be excellent in sliding, sliding-rolling and erosive-abrasive wear. Whereas, boron steels are often an economically favorable alternative used in applications subjected to erosive and abrasive wear. In this study the erosive-abrasive wear resistance of CFB and boron steels with different heat treatments were compared and the effect of microstructure on wear was investigated. An application oriented dry-pot laboratory test method with 8-10 mm granite gravel was used to produce erosive-abrasive wear environment. The tested materials were CFB and boron steels. The CFB steels had hardness values of 500 and 600 HV. The boron steels, both quenched and quenched and tempered, had a hardness of 500 HV. The influence of the microstructures on wear was studied by wear test results as well as by optical and scanning electron microscopy. The phase compositions were determined by XRD. The effect of wear, in addition to weight loss was also characterized by surface profilometry, hardness and hardness profile determinations. The wear resistance of the steels was compared with results achieved in a field test in an industrial mining application. Moreover, the effect of the different microstructures on wear behavior is discussed. The carbide free bainitic steels showed better wear performance than the martensitic boron steels. The boron steels were subjected to microcutting and microploughing, whereas the CFB steels exhibited more shallow impact craters with thin platelets.

General information

Publication status: Published
MoE publication type: D3 Professional conference proceedings
Organisations: Materials Science, Research group: Materials Characterization, Luleå University of Technology, University of Oulu, Faculty of Technology
Contributors: Vuorinen, E., Heino, V., Ojala, N., Haiko, O., Hedayati, A.
Publication date: 2016

Host publication information

Title of host publication: The 17th Nordic Symposium on Tribology - NORDTRIB 2016 14th - 17th June 2016 Aulanko, Hämeenlinna, Finland
ASJC Scopus subject areas: Metals and Alloys, Engineering (miscellaneous)
Keywords: Steel, Erosion wear, Abrasive wear, Microstructure
Electronic versions: 

Research output: Chapter in Book/Report/Conference proceedingConference contributionProfessional

Evaluating a Future Remote Control Environment with an Experience-Driven Science Fiction Prototype

The case study presented in this paper aimed at discovering opportunities for ambient intelligence and new interaction methods for a future remote crane-operating environment. The theoretical objective was to carry out an experience-driven research project in an industrial work context, and the practical objective was to create and evaluate a future oriented science fiction prototype. The work was carried out in close co-operation with an industrial partner who was a domain expert in the field of crane industry. The aim was to focus on clearly defined user experience goals to which the industrial partner committed. The consequent immediate objective was to focus on two explicit experiences relating to 'Feeling of being motivated' and to 'Sense of community' that were placed at the core of the design investigations. These experiences were deliberated into a science fiction prototype entitled 'Remote operator's day in a future control centre'. The science fiction prototype was further introduced to users by twofold means: as a plain, simple short story and through an interactive experience path. The main contribution of the paper is to demonstrate how an emerging technology research of a new domain may employ science fiction prototyping method as a primary means of experience design investigations.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Augmented Human Activities (AHA), VTT Technical Research Centre of Finland, Jyväskylän yliopisto, Konecranes Ltd
Contributors: Kymalainen, T., Perala, P., Hakulinen, J., Heimonen, T., James, J., Pera, J.
Number of pages: 8
Pages: 81-88
Publication date: 12 Aug 2015

Host publication information

Title of host publication: Proceedings - 2015 International Conference on Intelligent Environments, IE 2015
Publisher: Institute of Electrical and Electronics Engineers Inc.
Article number: 7194274
ISBN (Electronic): 9781467366540
ASJC Scopus subject areas: Artificial Intelligence, Computer Science Applications, Engineering (miscellaneous), Social Sciences (miscellaneous)
Keywords: human-computer interaction (HCI), Intelligent environment (IE), remote crane operation, science fiction prototyping (SFP), user experience (UX)
Source: Scopus
Source ID: 84955492937

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Theory driven design and real proto typing of biomass pyrolitic stove

This article introduces a design approach integrating early design phase and model based engineering in order to develop innovative biomass gasifier system for rural communities in Africa. The need for such a systemic perspective is imposed by the imbrication of technical, ecological and cultural issues that cannot be ignored while designing new technology. The article proposes an integrated generic design theory approaches to discover and rank by order of importance system's variables and to single out most desired design parameters. A pre-design user requirement assessment was carried out to identify detailed stove's functions. Causal-ordering diagrams sketched for system's modelling. System functions were described graphically and synthesized through simple linear algebraic matrices. Contradictions in system functions were solved using Theory of Inventive Thinking (TRIZ 40). And system's optimization was done through simple Taguchi experimentation method. A two level L8 degree of freedom Taguchi table was used in the experimentation and optimization of the pyrolitic stove. The design approach was exemplified using the case of the "AKIBA" biomass stove.

General information

Publication status: Published
MoE publication type: A4 Article in a conference publication
Organisations: Kenya Industrial Research and Development Institute (KIRDI), Aalto University School of Engineering, Department of Engineering Design and Production, Aalto University
Contributors: Ogeya, M. C., Coatanéa, E., Medyna, G.
Number of pages: 10
Pages: 69-78
Publication date: 2013

Host publication information

Title of host publication: Proceedings of the International Conference on Engineering Design, ICED
Volume: 9 DS75-09
ISBN (Print): 9781904670520
ASJC Scopus subject areas: Engineering (miscellaneous), Industrial and Manufacturing Engineering, Modelling and Simulation
Keywords: Design theory, Early design phase, Innovation, Optimisation, Systems engineering
Source: Scopus
Source ID: 84897650359

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

Norjan valtakunnallinen lippu- ja maksujärjestelmä

The development of a nationwide ticketing system and a schedule and route guide is
included in Finland’s current Government Programme. This survey focuses on the
adoption process and the technical solutions relating to Norway’s interoperable
ticketing system. The goal is to clarify to what extent the technical solutions used in
Norway could be utilised in building the Finnish system, how the system’s
background organisation is set up and what, based on Norwegian experience, should
be taken into account when adopting an interoperable ticketing system.



It is possible to borrow the specifications for Finnish travel cards and ticket product
types from Norway’s national ticketing system. Other Norwegian specification
segments could be used to support the planning of corresponding functions for
Finland. The Norwegian national system is designed to combine regional background
systems rather than replace them, which does not correspond to Finland’s immediate
needs for regional authorities’ joint background system. A solution combining several
systems, such as in Norway, could, however, also be necessary for Finland in the
future in order to achieve nationwide interoperability. An interoperability
organisation in accordance with the Norwegian model is not suitable as such to
Finnish conditions. This is because the Norwegian IO-organisation, in principle, only
serves public organisations.



Norway’s national specification does not include an interface between the back-
ground system and field devices. In Finland this interface specification is necessary
for tendering the different parts of the system as well as for updating the existing field
devices to the new system. The interoperable ticketing system with specifications
should be built so that genuine competition between different suppliers is ensured
and the role of an individual supplier in the system is not too strong and binding.
Increasing information system know-how among public transport actors is necessary.
Future technologies should be taken into account in the design process.



Creating an interoperable nationwide ticketing system requires mutual understanding
between public transport authorities and central government about the goals, the
process, the requirements for the system and its benefits. The customer focus should
not be omitted. Building a system, even a complicated one, is useful, if it leads to easy
and simple usability for the customer.

General information

Publication status: Published
MoE publication type: D4 Published development or research report or study
Organisations: Department of Information Management and Logistics
Contributors: Rantala, T., Aura, T.
Number of pages: 45
Publication date: 2012

Publication information

Place of publication: Helsinki
Publisher: Liikennevirasto
ISBN (Electronic): 978-952-255-196-2
Original language: Finnish

Publication series

Name: Liikenneviraston tutkimuksia ja selvityksiä
Publisher: Liikennevirasto
No.: 44/2012
ISSN (Electronic): 1798-6664
ASJC Scopus subject areas: Engineering (miscellaneous)
Keywords: interoperable, Norway, public transport, ticketing system, travel card standard

Research output: Book/ReportCommissioned reportProfessional

Nonlinear pulse compression by the second-harmonic generation in quasiphase and group-velocity matched samples

We investigate numerically the second-harmonic generation from near infrared 100 fs pulses in periodically and aperiodically poled lithium niobate crystals, taking into account the group-velocity mismatch, the group-velocity dispersion, and self-action effects. For the first time, we show that a tenfold pulse compression can be obtained at both fundamental and second-harmonic frequencies. The mechanism of compression and the pertinent quality factors are discussed.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Academy of Sciences of the Republic of Uzbekistan, NooEL, University “Roma Tre”
Contributors: Sapaev, U. K., Kulagin, I. A., Usmanov, T., Assanto, G.
Number of pages: 6
Pages: 41-46
Publication date: Jan 2011
Peer-reviewed: Yes

Publication information

Journal: JOURNAL OF RUSSIAN LASER RESEARCH
Volume: 32
Issue number: 1
ISSN (Print): 1071-2836
Ratings: 
  • Scopus rating (2011): CiteScore 0.63 SJR 0.281 SNIP 0.552
Original language: English
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics, Engineering (miscellaneous)
Keywords: cascading, frequency doubling, lithium niobate, nonlinear pulse compression, parametric effects, quasiphase matching
Source: Scopus
Source ID: 79952937918

Research output: Contribution to journalArticleScientificpeer-review

Photostable second-harmonic generation from a single KTiOPO4 nanocrystal for nonlinear microscopy

A study was conducted to report the observation and the characterization of nanometric-sized crystals extracted by centrifugation from KTP (potassium titanyl phosphate) powder. In situ atomic force microscopy (AFM) analysis of its size and analysis of its second-harmonic emission properties were performed for a well-isolated single nanocrystal. The highly efficient nonlinear response leads to the emission of several SHG photons and in a photostable and blinking-free manner due to non-resonant coherent interaction. The study retrieved the in situ three-dimensional crystal orientation by recovering the radiation pattern from the recorded defocused images. Solution-based chemical synthesis of KTP nanocrystals with a monodisperse size controlled by capping agents should lead to optimized KTP nanocrystallites and to a more accurate estimate of the size-detection threshold. Fully characterized nano-KTPs are also attractive for the development of novel schemes of nonlinear microscopy.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Laboratoire de Photonique Quantique et Moléculaire-ENS Cachan, UMR CNRS 8537, Laboratoire de Physique de la Matière Condensée-Ecole Polytechnique-CNRS, Ecole Polytechnique, Cristal Laser S.A.
Contributors: Le Xuan, L., Zhou, C., Slablab, A., Chauvat, D., Tard, C., Perruchas, S., Gacoin, T., Villeval, P., Roch, J.
Number of pages: 5
Pages: 1332-1336
Publication date: Sep 2008
Peer-reviewed: Yes

Publication information

Journal: Small
Volume: 4
Issue number: 9
ISSN (Print): 1613-6810
Ratings: 
  • Scopus rating (2008): SJR 3.884 SNIP 1.517
Original language: English
ASJC Scopus subject areas: Biomaterials, Engineering (miscellaneous), Biotechnology, Medicine(all)
Keywords: Nanocrystals, Nanoparticles, Nonlinear microscopy, Second-harmonic generation
Source: Scopus
Source ID: 52649175511

Research output: Contribution to journalArticleScientificpeer-review