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  • 1.
    Viteckova, Slavka
    et al.
    Faculty of Biomedical Engineering, Czech Technical University in Prague, Prague, Czech Republic.
    Khandelwal, Siddhartha
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Kutilek, Patrik
    Faculty of Biomedical Engineering, Czech Technical University in Prague, Prague, Czech Republic.
    Krupicka, Radim
    Faculty of Biomedical Engineering, Czech Technical University in Prague, Prague, Czech Republic.
    Szabo, Zoltan
    Faculty of Biomedical Engineering, Czech Technical University in Prague, Prague, Czech Republic.
    Gait symmetry methods: Comparison of waveform-based Methods and recommendation for use2020Ingår i: Biomedical Signal Processing and Control, ISSN 1746-8094, E-ISSN 1746-8108, Vol. 55, artikel-id 101643Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gait symmetry has been shown to be a relevant measure for differentiating between normal and pathological gait. Although a number of symmetry methods exist, it is not clear which of these methods should be used as they have been developed using data collected from varying experimental protocols. This paper presents a comparison of state-of-the-art waveform-based symmetry methods and tests them on walking data collected from different environments. Acceleration signals collected from the ankle are used to analyse symmetry methods under different signal circumstances, such as phase shift, waveform shape difference, signal length (i.e. number of gait cycles) and gait initiation phase. The cyclogram based method is invariant to signal phase shifts, signal length and the gait initiation phase. The trend symmetry method is not affected by signal scaling and the gait initiation phase but is affected by signal length depending on the environment. Similar to the trend method, the cross-correlation symmetry method is not responsive to signal scaling and the gait initiation phase. The results of the symbolic method are not influenced by signal scaling, gait initiation and depending on the environment by the signal phase shift. From the results of the performed analysis, we recommend the trend method to gait symmetry assessment. The comparison of waveform-based symmetry methods brings new knowledge that will help in selecting an appropriate method for gait symmetry assessment under different experimental protocols. © 2019 Elsevier Ltd. All rights reserved.

  • 2.
    Gholami Shahbandi, Saeed
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Magnusson, Martin
    Örebro University, Örebro, Sweden.
    2D Map Alignment With Region Decomposition2019Ingår i: Autonomous Robots, ISSN 0929-5593, E-ISSN 1573-7527, Vol. 43, nr 5, s. 1117-1136Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In many applications of autonomous mobile robots the following problem is encountered. Two maps of the same environment are available, one a prior map and the other a sensor map built by the robot. To benefit from all available information in both maps, the robot must find the correct alignment between the two maps. There exist many approaches to address this challenge, however, most of the previous methods rely on assumptions such as similar modalities of the maps, same scale, or existence of an initial guess for the alignment. In this work we propose a decomposition-based method for 2D spatial map alignment which does not rely on those assumptions. Our proposed method is validated and compared with other approaches, including generic data association approaches and map alignment algorithms. Real world examples of four different environments with thirty six sensor maps and four layout maps are used for this analysis. The maps, along with an implementation of the method, are made publicly available online. © 2018, The Author(s).

  • 3.
    Friel, Ross
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Gerling-Gedin, Maria
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Nilsson, Emil
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab). Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Andreasson, Björn Pererik
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    3D Printed Radar Lenses with Anti-Reflective Structures2019Ingår i: Designs, E-ISSN 2411-9660, Vol. 3, nr 2, artikel-id 28Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The purpose of this study was to determine if 3D printed lenses with wavelength specific anti-reflective (AR) surface structures would improve beam intensity and thus radar efficiency for a Printed Circuit Board (PCB)-based 60 GHz radar. This would have potential for improved low-cost radar lenses for the consumer product market. Methods: A hyperbolic lens was designed in 3D Computer Aided Design (CAD) software and was then modified with a wavelength specified AR structure. Electromagnetic computer simulation was performed on both the ‘smooth’ and ‘AR structure’ lenses and compared to actual 60 GHz radar measurements of 3D printed polylactic acid (PLA) lenses. Results: The simulation results showed an increase of 10% in signal intensity of the AR structure lens over the smooth lens. Actual measurement showed an 8% increase in signal of the AR structure lens over the smooth lens. Conclusions: Low cost and readily available Fused Filament Fabrication (FFF) 3D printing has been shown to be capable of printing an AR structure coated hyperbolic lens for millimeter wavelength radar applications. These 3D Printed AR structure lenses are effective in improving radar measurements over non-AR structure lenses.

  • 4.
    Savas, Süleyman
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Ul-Abdin, Zain
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Nordström, Tomas
    RISE Research Institutes of Sweden, Gothenburg, Sweden.
    A Configurable Two Dimensional Mesh Network-on-Chip Implementation in Chisel2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    On-chip communication plays a significant role in the performance of manycore architectures. Therefore, they require a proper on-chip communication infrastructure that can scale with the number of the cores. As a solution, network-on-chip structures have emerged and are being used.

    This paper presents description of a two dimensional mesh network-on-chip router and a network interface, which are implemented in Chisel to be integrated to the rocket chip generator that generates RISC-V (rocket) cores. The router is implemented in VHDL as well and the two implementations are verified and compared.

    Hardware resource usage and performance of different sized networks are analyzed. The implementations are synthesized for a Xilinx Ultrascale FPGA via Xilinx tools for the hardware resource usage and clock frequency results. The performance results including latency and throughput measurements with different traffic patterns, are collected with cycle accurate emulations. 

    The implementations in Chisel and VHDL do not show a significant difference. Chisel requires around 10% fewer lines of code, however, the difference in the synthesis results is negligible. Our latency result are better than the majority of the other studies. The other results such as hardware usage, clock frequency, and throughput are competitive when compared to the related works.

  • 5.
    Savas, Süleyman
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Ul-Abdin, Zain
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Nordström, Tomas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    A Framework to Generate Domain-Specific Manycore Architectures from Dataflow Programs2019Ingår i: Microprocessors and microsystems, ISSN 0141-9331, E-ISSN 1872-9436Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the last 15 years we have seen, as a response to power and thermal limits for current chip technologies, an explosion in the use of multiple and even many computer cores on a single chip. But now, to further improve performance and energy efficiency, when there are potentially hundreds of computing cores on a chip, we see a need for a specialization of individual cores and the development of heterogeneous manycore computer architectures.

    However, developing such heterogeneous architectures is a significant challenge. Therefore, we propose a design method to generate domain specific manycore architectures based on RISC-V instruction set architecture and automate the main steps of this method with software tools. The design method allows generation of manycore architectures with different configurations including core augmentation through instruction extensions and custom accelerators. The method starts from developing applications in a high-level dataflow language and ends by generating synthesizable Verilog code and cycle accurate emulator for the generated architecture.

    We evaluate the design method and the software tools by generating several architectures specialized for two different applications and measure their performance and hardware resource usages. Our results show that the design method can be used to generate specialized manycore architectures targeting applications from different domains. The specialized architectures show at least 3 to 4 times better performance than the general purpose counterparts. In certain cases, replacing general purpose components with specialized components saves hardware resources. Automating the method increases the speed of architecture development and facilitates the design space exploration of manycore architectures.

  • 6.
    Aramrattana, Maytheewat
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Larsson, Tony
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Jansson, Jonas
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Nåbo, Arne
    The Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    A simulation framework for cooperative intelligent transport systems testing and evaluation2019Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour, ISSN 1369-8478, E-ISSN 1873-5517, Vol. 61, s. 268-280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Connected and automated driving in the context of cooperative intelligent transport systems (C-ITS) is an emerging area in transport systems research. Interaction and cooperation between actors in transport systems are now enabled by the connectivity by means of vehicle-to-vehicle and vehicle-to-infrastructure (V2X) communication. To ensure the goals of C-ITS, which are safer and more efficient transport systems, testing and evaluation are required before deployment of C-ITS applications. Therefore, this paper presents a simulation framework—consisting of driving-, traffic-, and network-simulators—for testing and evaluation of C-ITS applications. Examples of cooperative adaptive cruise control (CACC) applications are presented, and are used as test cases for the simulation framework as well as to elaborate on potential use cases of it. Challenges from combining the simulators into one framework, and limitations are reported and discussed. Finally, the paper concludes with future development directions, and applications of the simulation framework in testing and evaluation of C-ITS. © 2017 Elsevier Ltd. All rights reserved.

  • 7.
    Pejner, Norell Margaretha
    et al.
    Högskolan i Halmstad, Akademin för hälsa och välfärd, Centrum för forskning om välfärd, hälsa och idrott (CVHI).
    Ourique de Morais, Wagner
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Lundström, Jens
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Laurell, Hélène
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, Centrum för innovations-, entreprenörskaps- och lärandeforskning (CIEL).
    Skärsäter, Ingela
    Högskolan i Halmstad, Akademin för hälsa och välfärd, Centrum för forskning om välfärd, hälsa och idrott (CVHI).
    A Smart Home System for Information Sharing, Health Assessments, and Medication Self-Management for Older People: Protocol for a Mixed-Methods Study2019Ingår i: JMIR Research Protocols, ISSN 1929-0748, E-ISSN 1929-0748, Vol. 8, nr 4, artikel-id e12447Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Older adults often want to stay in a familiar place, such as their home, as they get older. This so-called aging in place, which may involve support from relatives or care professionals, can promote older people’s independence and well-being. The combination of aging and disease, however, can lead to complex medication regimes, and difficulties for care providers in correctly assessing the older person's health. In addition, the organization of the health care is fragmented, which makes it difficult for health professionals to encourage older people to participate in their care. It is also a challenge to perform adequate health assessment and appropriate communication between health care professionals.

    Objective: The purpose of this paper is to describe the design for an integrated home-based system that can acquire and compile health-related evidence for guidance and information sharing among care providers and care receivers in order to support and promote medication self-management among older people.

    Methods: The authors used a participatory design (PD) approach for this mixed-method project, which was divided into four phases: Phase I, Conceptualization, consisted of the conceptualization of a system to support medication self- management, objective health assessments, and communication between health care professionals. Phase II, Development of a System, consisted of building and bringing together the conceptualized systems from phase I. Phases III (pilot study) and IV (a full-scale study) are described briefly.

    Results: Our participants in phase I were people who were involved in some way in the care of older adults, and included older adults themselves, relatives of older adults, care professionals, and industrial partners. With input from phase I participants, we identified two relevant concepts for promoting medication self-management, both of which related to systems that participants believed could provide guidance for the older adults themselves, relatives of older adults, and care professionals. The system will also encourage information sharing between care providers and care receivers. The first is the concept of the Intelligent Friendly Home (IAFH), defined as an integrated residential system that evolves to sense, reason and act in response to individual needs, preferences and behaviors as these change over time. The second concept is the MedOP system, a system that would be supported by the IAFH, and which consists of three related components: one that assess health behaviors, another that communicates health data, and a third that promotes medication self-management.

    Conclusions: The participants in this project were older adults, relatives of older adults, care professionals, and our industrial partners. With input from the participants, we identified two main concepts that could comprise a system for health assessment, communication and medication self-management: the Intelligent Friendly Home (IAFH), and the MedOP system. These concepts will be tested in this study to determine whether they can facilitate and promote medication self-management in older people. © The authors. All rights reserved. 

  • 8.
    Alonso-Fernandez, Fernando
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Farrugia, Reuben A.
    University of Malta, Msida, Malta.
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Fierrez, Julian
    Universidad Autonoma de Madrid, Madrid, Spain.
    Gonzalez-Sosa, Ester
    Nokia Bell-Labs, Madrid, Spain.
    A Survey of Super-Resolution in Iris Biometrics with Evaluation of Dictionary-Learning2019Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 6519-6544Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The lack of resolution has a negative impact on the performance of image-based biometrics. While many generic super-resolution methods have been proposed to restore low-resolution images, they usually aim to enhance their visual appearance. However, an overall visual enhancement of biometric images does not necessarily correlate with a better recognition performance. Reconstruction approaches need thus to incorporate specific information from the target biometric modality to effectively improve recognition performance. This paper presents a comprehensive survey of iris super-resolution approaches proposed in the literature. We have also adapted an Eigen-patches reconstruction method based on PCA Eigentransformation of local image patches. The structure of the iris is exploited by building a patch-position dependent dictionary. In addition, image patches are restored separately, having their own reconstruction weights. This allows the solution to be locally optimized, helping to preserve local information. To evaluate the algorithm, we degraded high-resolution images from the CASIA Interval V3 database. Different restorations were considered, with 15 × 15 pixels being the smallest resolution evaluated. To the best of our knowledge, this is among the smallest resolutions employed in the literature. The experimental framework is complemented with six publicly available iris comparators, which were used to carry out biometric verification and identification experiments. Experimental results show that the proposed method significantly outperforms both bilinear and bicubic interpolation at very low-resolution. The performance of a number of comparators attain an impressive Equal Error Rate as low as 5%, and a Top-1 accuracy of 77-84% when considering iris images of only 15 × 15 pixels. These results clearly demonstrate the benefit of using trained super-resolution techniques to improve the quality of iris images prior to matching. © 2018, Emerald Publishing Limited.

  • 9.
    Pink, Sarah
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS). RMIT University, Melbourne, Australia.
    Fors, Vaike
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Glöss, Mareike
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Automated futures and the mobile present: In-car video ethnographies2019Ingår i: Ethnography, ISSN 1466-1381, E-ISSN 1741-2714, Vol. 20, nr 1, s. 88-107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New technological possibilities associated with autonomous driving (AD) cars are generating new questions and imaginaries about automated futures. In this article we advance a theoretical-methodological approach towards researching this context based in design anthropological theory and sensory ethnographic practice. In doing so we explain and discuss the findings of an in-car video ethnography study designed to investigate the usually unspoken and not necessarily visible elements of car-based mobility. Such an approach is needed, we argue, both in order to inform a research agenda that is capable of addressing the emergence of automated vehicles specifically, as well as in preparation for understanding the implications of automation more generally as human mobility is increasingly entangled with automated technologies and the future imaginaries associated with them. © The British Association of Hand Therapists Ltd 2017.

  • 10.
    Cooney, Martin
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Ong, Linda
    I+ srl, Florence, Italy.
    Pashami, Sepideh
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Järpe, Eric
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Ashfaq, Awais
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Avoiding Improper Treatment of Dementia Patients by Care Robots2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    The phrase “most cruel and revolting crimes” has been used to describe some poor historical treatment of vulnerable impaired persons by precisely those who should have had the responsibility of protecting and helping them. We believe we might be poised to see history repeat itself, as increasingly humanlike aware robots become capable of engaging in behavior which we would consider immoral in a human–either unknowingly or deliberately. In the current paper we focus in particular on exploring some potential dangers affecting persons with dementia (PWD), which could arise from insufficient software or external factors, and describe a proposed solution involving rich causal models and accountability measures: Specifically, the Consequences of Needs-driven Dementia-compromised Behaviour model (C-NDB) could be adapted to be used with conversation topic detection, causal networks and multi-criteria decision making, alongside reports, audits, and deterrents. Our aim is that the considerations raised could help inform the design of care robots intended to support well-being in PWD.

  • 11.
    Bocharova, Irina
    et al.
    Department of Information Systems, St. Petersburg University of Information Technologies, Mechanics and Optics, St.-Petersburg, Russia & Institute of Computer Science, University of Tartu, Estonia.
    Kudryashov, Boris
    Department of Information Systems, St. Petersburg University of Information Technologies, Mechanics and Optics, St.-Petersburg, Russia & Institute of Computer Science, University of Tartu, Estonia.
    Rabi, Maben
    Högskolan i Halmstad.
    Lyamin, Nikita
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Dankers, Wouter
    Volvo GTT, Goteborg, Sweden.
    Frick, Erik
    AstaZero, Hällered, Sandhult, Sweden.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). Department of Electrical Engineering, Western Norway University of Applied Sciences, Bergen, Norway.
    Characterizing Packet Losses in Vehicular Networks2019Ingår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 68, nr 9, s. 8347-8358Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    To enable testing and performance evaluation of new connected and autonomous driving functions, it is important to characterize packet losses caused by degradation in vehicular (V2X) communication channels. In this paper we suggest an approach to constructing packet loss models based on the socalled Pseudo-Markov chains (PMC). The PMC based model needs only short training sequences, has low computational complexity, and yet provides more precise approximations than known techniques. We show how to learn PMC models from either empirical records of packet receptions, or from analytical models of fluctuations in the received signal strength. In particular, we validate our approach by applying it on (i) V2X packet reception data collected from an active safety test run, which used the LTE network of the AstaZero automotive testing site in Sweden, and (ii) variants of the Rician fading channel models corresponding to two models of correlations of packet losses. We also show that initializing the Baum-Welch algorithm with a second order PMC model leads to a high accuracy model.

  • 12.
    Hilt, Benoît
    et al.
    University of Haute Alsace, Mulhouse, Colmar, France.
    Berbineau, MarionFrench Institute of Science and Technology, Spatial Planning, Development, and Networks, Villeneuve d'Ascq, France.Vinel, AlexeyHögskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).Jonsson, MagnusHögskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).Pirovano, AlainÉcole Nationale de l’Aviation Civile, Toulouse, France.
    Communication Technologies for Vehicles: 14th International Workshop, Nets4Cars/Nets4Trains/Nets4Aircraft 2019, Colmar, France, May 16–17, 2019, Proceedings2019Proceedings (redaktörskap) (Refereegranskat)
  • 13.
    Varshosaz, Mahsa
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Mousavi, Mohammad Reza
    Department of Informatics, University of Leicester, Leicester, United Kingdom.
    Comparative Expressiveness of Product Line Calculus of Communicating Systems and 1-Selecting Modal Transition Systems2019Ingår i: SOFSEM 2019: Theory and Practice of Computer Science / [ed] Barbara Catania, Rastislav Královič, Jerzy Nawrocki & Giovanni Pighizzini, Cham: Springer, 2019, s. 490-503Konferensbidrag (Refereegranskat)
    Abstract [en]

    Product line calculus of communicating systems (PL-CCSs) is a process calculus proposed to model the behavior of software product lines. Modal transition systems (MTSs) are also used to model variability in behavioral models. MTSs are known to be strictly less expressive than PL-CCS. In this paper, we show that the extension of MTSs with hyper transitions by Fecher and Schmidt, called 1-selecting modal transition systems (1MTSs), closes this expressiveness gap. To this end, we propose a novel notion of refinement for 1MTSs that makes them more suitable for specifying variability for software product lines and prove its various essential properties. © Springer Nature Switzerland AG 2019

  • 14.
    Lyamin, Nikita
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Bellalta, Boris
    Universitat Pompeu Fabra, Barcelona, Catalunya, Spain.
    Configuring the Decentralized Congestion Control for ETSI ITS-G5 C-ITS Applications2019Ingår i: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Decentralized Congestion Control (DCC) is one the central components of inter-vehicular communications protocol stack enabling Cooperative Intelligent Transportation System (C-ITS). In this letter we first present an analytical framework that allows to tune parameters of the DCC algorithm specified by ETSI. Then we suggest two approaches to optimize the DCC configuration using our framework. Finally, we evaluate the performance of the proposed approaches using detailed simulation experiments. We demonstrate that proposed approaches are able to control channel busy ratio stably, while proposed analytical model precisely estimates application level metrics.

  • 15.
    Zhang, Ke
    et al.
    University of Electronic Science and Technology of China, Chengdu, China.
    Mao, Yuming
    University of Electronic Science and Technology of China, Chengdu, China.
    Leng, Supeng
    University of Electronic Science and Technology of China, Chengdu, China.
    Maharjan, Sabita
    Simula Research Laboratory, Fornebu, Norway & University of Oslo, Oslo, Norway.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Zhang, Yan
    University of Oslo, Oslo, Norway.
    Contract-theoretic Approach for Delay Constrained Offloading in Vehicular Edge Computing Networks2019Ingår i: Journal on spesial topics in mobile networks and applications, ISSN 1383-469X, E-ISSN 1572-8153, Vol. 24, nr 3, s. 1003-1014Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mobile Edge Computing (MEC) is a promising solution to improve vehicular services through offloading computation to cloud servers in close proximity to mobile vehicles. However, the self-interested nature together with the high mobility characteristic of the vehicles make the design of the computation offloading scheme a significant challenge. In this paper, we propose a new Vehicular Edge Computing (VEC) framework to model the computation offloading process of the mobile vehicles running on a bidirectional road. Based on this framework, we adopt a contract theoretic approach to design optimal offloading strategies for the VEC service provider, which maximize the revenue of the provider while enhancing the utilities of the vehicles. To further improve the utilization of the computing resources of the VEC servers, we incorporate task priority distinction as well as additional resource providing into the design of the offloading scheme, and propose an efficient VEC server selection and computing resource allocation algorithm. Numerical results indicate that our proposed schemes greatly enhance the revenue of the VEC provider, and concurrently improve the utilization of cloud computing resources. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

  • 16.
    Hernandez-Diaz, Kevin
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Alonso-Fernandez, Fernando
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Cross Spectral Periocular Matching using ResNet Features2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Periocular recognition has gained attention in the last years thanks to its high discrimination capabilities in less constraint scenarios than other ocular modalities. In this paper we propose a method for periocular verification under different light spectra using CNN features with the particularity that the network has not been trained for this purpose. We use a ResNet-101 pretrained model for the ImageNet Large Scale Visual Recognition Challenge to extract features from the IIITD Multispectral Periocular Database. At each layer the features are compared using χ 2 distance and cosine similitude to carry on verification between images, achieving an improvement in the EER and accuracy at 1% FAR of up to 63.13% and 24.79% in comparison to previous works that employ the same database. In addition to this, we train a neural network to match the best CNN feature layer vector from each spectrum. With this procedure, we achieve improvements of up to 65% (EER) and 87% (accuracy at 1% FAR) in cross-spectral verification with respect to previous studies.

  • 17.
    Hernandez-Diaz, Kevin
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Alonso-Fernandez, Fernando
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Cross-Spectral Biometric Recognition with Pretrained CNNs as Generic Feature Extractors2019Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Periocular recognition has gained attention in the last years thanks to its high discrimination capabilities in less constraint scenarios than face or iris. In this paper we propose a method for periocular verification under different light spectra using CNN features with the particularity that the network has not been trained for this purpose. We use a ResNet-101 pretrained model for the ImageNet Large Scale Visual Recognition Challenge to extract features from the IIITD Multispectral Periocular Database. At each layer the features are compared using χ 2 distance and cosine similitude to carry on verification between images, achieving an improvement in the EER and accuracy at 1% FAR of up to 63.13% and 24.79% in comparison to previous works that employ the same database. In addition to this, we train a neural network to match the best CNN feature layer vector from each spectrum. With this procedure, we achieve improvements of up to 65% (EER) and 87% (accuracy at 1% FAR) in cross-spectral verification with respect to previous studies.

  • 18.
    Mashad Nemati, Hassan
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Data analytics for weak spot detection in power distribution grids2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This research aims to develop data-driven methods that extract information from the available data in distribution grids for detecting weak spots, including the components with degraded reliability and areas with power quality problems. The results enable power distribution companies to change from reactive maintenance to predictive maintenance by deriving benefits from available data. In particular, the data is exploited for three purposes: (a) failure pattern discovery, (b) reliability evaluation of power cables, and (c) analyzing and modeling propagation of power quality disturbances (PQDs) in low-voltage grids.

    To analyze failure characteristics it is important to discover which failures share common features, e.g., if there are any types of failures that happen mostly in certain parts of the grid or at certain times. This analysis provides information about correlation between different features and identifying the most vulnerable components. In this case, we applied statistical analysis and association rules to discover failure patterns. Furthermore, we propose a visualization of the correlations between different factors representing failures by using an approximated Bayesian network. We show that the Bayesian Network constructed based on the interesting rules of two items is a good approximation of the real dataset.

    The main focus of reliability evaluation is on failure rate estimation and reliability ranking. In case of power cables, the limited amount of recorded events makes it difficult to perform failure rate modeling. Therefore, we propose a method for interpreting the results of goodness-of-fit measures with confidence intervals, estimated using synthetic data.

    To perform reliability ranking of power cables, in addition to the age of cables, we consider other factors. Then, we use the proportional hazard model (PHM) to assess the impact of the factors and calculate the failure rate of each individual cable. In reliability evaluation, it is important to consider the fact that power cables are repairable components. We discuss that the conclusions about different factors in PHM and cables ranking will be misleading if one considers the cables as non-repairable components.

    In low-voltage distribution grids, analyzing PQDs is important as we are moving towards smart grids with the next generation of producers and consumers. Installing Power Quality and Monitoring Systems (PQMS) at all the nodes in the network, for monitoring the impacts of the new consumer/producer, is prohibitively expensive. Instead, we demonstrate that power companies can utilize the available smart meters, which are widely deployed in the low-voltage grids, for monitoring power quality events and identifying areas with power quality problems. In particular, several models for propagation of PQDs, within neighbor customers in different levels of the grid topology, are investigated. The results show that meters data can be used to detect and describe propagation in low-voltage grids.

    The developed methods of (a) failure pattern discovery are applied on data from Halmstad Energi och Miljö (HEM Nät), Öresundskraft, Göteborg Energy, and Växjö Energy, four different distribution system operators in Sweden. The developed methods of (b) reliability evaluation of power cables and (c) analyzing and modeling propagation of PQDs are applied on data from HEM Nät.

  • 19.
    Ashfaq, Awais
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Lönn, Stefan
    Research and Development, Region Halland, Sweden.
    Nilsson, Håkan
    Economic Department, Region Halland, Sweden.
    Eriksson, Jonny
    Halland Hospital, Region Halland, Sweden.
    Kwatra, Japneet
    Brigham and Women’s Hospital, US.
    Yasin, Zayed
    Brigham and Women’s Hospital, US.
    Slutzman, Jonathan
    Massachusetts General Hospital, US.
    Wallenfeldt, Thomas
    CGI Group Inc. Consultants to Government and Industries, Sweden.
    Obermeyer, Ziad
    School of Public Health, University of California at Berkeley, US.
    Anderson, Philip
    Department of Emergency Medicine, Brigham & Women’s Hospital, Harvard Medical School, Boston, US..
    Lingman, Markus
    Halland Hospital, Region Halland, Sweden.
    Data Profile: Regional Healthcare Information Platform in Halland, Sweden2019Ingår i: International Journal of Epidemiology, ISSN 0300-5771, E-ISSN 1464-3685Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accurate and comprehensive healthcare data coupled with modern analytical tools can play a vital role in enabling care providers to make better-informed decisions, leading to effective and cost-efficient care delivery. This paper describes a novel strategic healthcare analysis and research platform that encapsulates 360-degree pseudo-anonymized data covering clinical, operational capacity and financial data on over 500,000 patients treated since 2009 across all care delivery units in the county of Halland, Sweden. The over-arching goal is to develop a comprehensive healthcare data infrastructure that captures complete care processes at individual, organizational and population levels. These longitudinal linked healthcare data are a valuable tool for research in a broad range of areas including health economy and process development using real world evidence.

    Key messages

    Structured and standardized variables have been linked from different regional healthcare sources into a research information platform including all healthcare visits in the county of Halland in Sweden, from 2009 to date.

    Since 2015, the regional information platform integrates a cost component to each healthcare visit: thus being able to quantify patient level value, safety and cost efficiency across the continuum of care.

  • 20.
    Cooney, Martin
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Berck, Peter
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Designing a Robot Which Paints With a Human: Visual Metaphors to Convey Contingency and Artistry2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    Socially assistive robots could contribute to fulfilling an important need for interaction in contexts where human caregivers are scarce–such as art therapy, where peers, or patients and therapists, can make art together. However, current art-making robots typically generate art either by themselves, or as tools under the control of a human artist; how to make art together with a human in a good way has not yet received much attention, possibly because some concepts related to art, such as emotion and creativity, are not yet well understood. The current work reports on our use of a collaborative prototyping approach to explore this concept of a robot which can paint together with people. The result is a proposed design, based on an idea of using visual metaphors to convey contingency and artistry. Our aim is that the identified considerations will help support next steps, toward supporting positive experiences for people through art-making with a robot.

  • 21.
    Amadeo, Marica
    et al.
    Dipartimento DIIES, Università Mediterranea di Reggio Calabria, Reggio Calabria, Italy.
    Campolo, Claudia
    Dipartimento DIIES, Università Mediterranea di Reggio Calabria, Reggio Calabria, Italy.
    Molinaro, Antonella
    Dipartimento DIIES, Università Mediterranea di Reggio Calabria, Reggio Calabria, Italy & Laboratoire des Signaux et Systémes (L2S), CentraleSupélec-CNRS-Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
    Harri, Jerome
    Department of Communication Systems, EURECOM, Sophia Antipolis, France.
    Rothenberg, Christian Esteve
    School of Electrical and Computer Engineering, University of Campinas (UNICAMP), Campinas, Brazil.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Enhancing the 3GPP V2X Architecture with Information-Centric Networking2019Ingår i: Future Internet, ISSN 1999-5903, E-ISSN 1999-5903, Vol. 11, nr 9, artikel-id 199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Vehicle-to-everything (V2X) communications allow a vehicle to interact with other vehicles and with communication parties in its vicinity (e.g., road-side units, pedestrian users, etc.) with the primary goal of making the driving and traveling experience safer, smarter and more comfortable. A wide set of V2X-tailored specifications have been identified by the Third Generation Partnership Project (3GPP) with focus on the design of architecture enhancements and a flexible air interface to ensure ultra-low latency, highly reliable and high-throughput connectivity as the ultimate aim. This paper discusses the potential of leveraging Information-Centric Networking (ICN) principles in the 3GPP architecture for V2X communications. We consider Named Data Networking (NDN) as reference ICN architecture and elaborate on the specific design aspects, required changes and enhancements in the 3GPP V2X architecture to enable NDN-based data exchange as an alternative/complementary solution to traditional IP networking, which barely matches the dynamics of vehicular environments. Results are provided to showcase the performance improvements of the NDN-based proposal in disseminating content requests over the cellular network against a traditional networking solution. © 2019 by the authors.

  • 22.
    Teng, Xudong
    et al.
    Key Laboratory of Modern Acoustics, Ministry of Education, Institute of Acoustics, Nanjing University, Nanjing, China & School of Electronic and Electric Engineering, Shanghai University of Engineering Science, Shanghai, China.
    Zhang, Xin
    Nanjing Manse Acoustics Technology Co. Ltd., Nanjing, China.
    Fan, Yuantao
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Zhang, Dong
    Key Laboratory of Modern Acoustics, Ministry of Education, Institute of Acoustics, Nanjing University, Nanjing, China.
    Evaluation of Cracks in Metallic Material Using a Self-Organized Data-Driven Model of Acoustic Echo-Signal2019Ingår i: Applied Sciences: APPS, ISSN 1454-5101, E-ISSN 1454-5101, Vol. 9, nr 1, artikel-id 95Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Non-linear acoustic technique is an attractive approach in evaluating early fatigue as well as cracks in material. However, its accuracy is greatly restricted by external non-linearities of ultra-sonic measurement systems. In this work, an acoustical data-driven deviation detection method, called the consensus self-organizing models (COSMO) based on statistical probability models, was introduced to study the evolution of localized crack growth. By using pitch-catch technique, frequency spectra of acoustic echoes collected from different locations of a specimen were compared, resulting in a Hellinger distance matrix to construct statistical parameters such as z-score, p-value and T-value. It is shown that statistical significance p-value of COSMO method has a strong relationship with the crack growth. Particularly, T-values, logarithm transformed p-value, increases proportionally with the growth of cracks, which thus can be applied to locate the position of cracks and monitor the deterioration of materials. © 2018 by the authors. 

  • 23.
    Lindgren, Thomas
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS). Volvo Cars, Gothenburg, Sweden.
    Fors, Vaike
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Pink, Sarah
    Monash University, Melbourne, Australia.
    Bergquist, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Experiencing the Future Car: Anticipatory UX as a Social and Digital Phenomenon2019Ingår i: Scandinavian Journal of Information Systems, ISSN 0905-0167, E-ISSN 1901-0990, Vol. 31, nr 1, artikel-id 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In order to be innovative and competitive, the automotive industry seeks to understand how to attract new customers, even before they have experienced the product. User Experience (UX) research often provides insights into situated uses of products, and reflections after their use, however tells us little about how products and services are experienced before use. We propose anticipation theory as a way to understand how shared experiences between people in an online discussion forum relate to UX of cars before they are actually experienced in real-life. We took an ethnographic approach to analyse the activities of members of a self-organised web-based discussion forum for Tesla car enthusiasts, to understand how product anticipation emerges in a digital-material setting. Our study identifies how anticipatory experiences create UX of car ownership which evolves through members’ engagement in a self-organised online community enabled through the digitalisation and connectivity of the car, and how such car experiences generate new forms of digital anticipation of the car. We conclude that the shift towards digitalisation of cars and subscription services creates a need for more interdisciplinary research into spatial and temporal aspects, where socially shared anticipatory experiences are increasingly important for the overall UX. © Scandinavian Journal of Information Systems,.

  • 24.
    Gonzalez-Sosa, Ester
    et al.
    Universidad Autonoma de Madrid, Madrid, Spain.
    Vera-Rodriguez, Ruben
    Universidad Autonoma de Madrid, Madrid, Spain.
    Fierrez, Julian
    Universidad Autonoma de Madrid, Madrid, Spain.
    Alonso-Fernandez, Fernando
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Patel, Vishal M.
    Rutgers University, NJ, USA.
    Exploring Body Texture From mmW Images for Person Recognition2019Ingår i: IEEE Transactions on Biometrics, Behavior, and Identity Science, E-ISSN 2637-6407, Vol. 1, nr 2, s. 139-151Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Imaging using millimeter waves (mmWs) has many advantages including the ability to penetrate obscurants, such as clothes and polymers. After having explored shape information retrieved from mmW images for person recognition, in this paper we aim to gain some insight about the potential of using mmW texture information for the same task, considering not only the mmW face, but also mmW torso and mmW wholebody. We report experimental results using the mmW TNO database consisting of 50 individuals based on both hand-crafted and learned features from Alexnet and VGG-face pretrained convolutional neural networks (CNNs) models. First, we analyze the individual performance of three mmW body parts, concluding that: 1) mmW torso region is more discriminative than mmW face and the whole body; 2) CNN features produce better results compared to hand-crafted features on mmW faces and the entire body; and 3) hand-crafted features slightly outperform CNN features on mmW torso. In the second part of this paper, we analyze different multi-algorithmic and multi-modal techniques, including a novel CNN-based fusion technique, improving verification results to 2% EER and identification rank-1 results up to 99%. Comparative analyses with mmW body shape information and face recognition in the visible and NIR spectral bands are also reported.

  • 25.
    Lindberg, Susanne
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Människa och Informationsteknologi (MI-lab).
    Gamification for Self-Directed Learning in Higher Education2019Ingår i: EDULEARN19 Proceedings, The International Academy of Technology, Education and Development, 2019, s. 1764-1773Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports on how gamification was used to promote Self-Directed Learning (SDL) in a course at a Swedish university. SDL is a strategy to lifelong learning [1], and essential in today's fast-changing society. However, it is challenging to achieve in higher education due to an emphasis on extrinsic motivation, and a tradition of the teacher being in control. Gamification is the use of game elements in non-game contexts [2] and has been used in educational contexts to motivate and engage students. Based on six years experience of teaching a gamified course, this paper seeks to answer the question: How can gamification support Self-Directed Learning in higher education?

    Self-directed learners continue to learn after the formal education has ended, which is essential in most professions today. The concept was described by Garrison [1] as having three dimensions: self-management (control), self-monitoring (responsibility) and motivation. This paper focuses on SDL as one perspective on learning, exploring the possibility for using gamification to support SDL.

    The paper reports on the experiences from the past six years of teaching a gamified course for first-year interaction design undergraduate students. A total of 253 students have taken the course, which implements several game elements: points, levels, choice, boss, collaboration, player status, and feedback. The students' experiences have been evaluated in several ways: the university’s standard summative evaluation form, since 2015 also a summative oral evaluation, and during 2016 and 2017 oral evaluations were also performed halfway through the course. The experiences from teaching the course are analysed using the three dimensions of SDL.

    For example, self-management is supported by the use of choice and the transparency of the player status page. In this case, the students were able to strategically choose some of their assignments, based on their level of ambition, through the overview of their current points. Self-monitoring is for example supported by the transparency of the reward structure and frequent external feedback; in this case, the point system and associated profile page.

    Furthermore, the reward structure, levels, choice, bosses, and the overall novelty of the concept supported motivation. The challenge in SDL is to internalise extrinsic motivation [1], and in this case the overall strong grades of the students, and their continued motivation to participate in course activities show that this was at least partly successful. In this case, the challenge was how to balance the game elements in order to achieve SLD, yet still maintain the structure of formal education.

    We formulate four ways in which gamification can support SDL: feedback can support all three dimensions of SDL and is one of the essential game elements in higher education; game elements can be used to direct students towards critical thinking activities, and thus support self-monitoring; choice can be used to support self-management, but is the most difficult to design; and intrinsic motivation can be supported by using appropriate reward structures and frequent feedback. 

    References:

    [1] Garrison, D.R., Self-directed learning: Toward a comprehensive model. Adult education quarterly, 1997. 48(1): p. 18-33.

    [2] Deterding, S. et al. From game design elements to gamefulness: defining gamification. in Proceedings of the 15th international academic MindTrek conference: Envisioning future media environments. 2011.

  • 26.
    Chalangar, Ebrahim
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS). Linköping University, Linköping, Sweden.
    Graphene-based nanocomposites for electronics and photocatalysis2019Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The development of future electronics depends on the availability of suitable functional materials. Printed electronics, for example, relies on access to highly conductive, inexpensive and printable materials, while strong light absorption and low carrier recombination rates are demanded in photocatalysis industry. Despite all efforts to develop new materials, it still remains a challenge to have all the desirable aspects in a single material. One possible route towards novel functional materials, with improved and unprecedented physical properties, is to form composites of different selected materials.

    In this work, we report on hydrothermal growth and characterization of graphene/zinc oxide (GR/ZnO) nanocomposites, suited for electronics and photocatalysis application. For conductive purposes, highly Al-doped ZnO nanorods grown on graphene nanoplates (GNPs) prevent the GNPs from agglomerating and promote conductive paths between the GNPs. The effect of the ZnO nanorod morphology and GR dispersity on the nanocomposite conductivity and GR/ZnO nanorod bonding strength were investigated by conductivity measurements and optical spectroscopy. The inspected samples show that growth in high pH solutions promotes a better graphene dispersity, higher doping and enhanced bonding between the GNPs and the ZnO nanorods. Growth in low pH solutions yield samples characterized by a higher conductivity and a reduced number of surface defects.

    In addition, different GR/ZnO nanocomposites, decorated with plasmonic silver iodide (AgI) nanoparticles, were synthesized and analyzed for solar-driven photocatalysis. The addition of Ag/AgI generates a strong surface plasmon resonance effect involving metallic Ag0, which redshifts the optical absorption maximum into the visible light region enhancing the photocatalytic performance under solar irradiation. A wide range of characterization techniques including, electron microscopy, photoelectron spectroscopy and x-ray diffraction confirm a successful formation of photocatalysts.

    Our findings show that the novel proposed GR-based nanocomposites can lead to further development of efficient photocatalyst materials with applications in removal of organic pollutants, or for fabrication of large volumes of inexpensive porous conjugated GR-semiconductor composites.

  • 27.
    Adam, Rania E.
    et al.
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Chalangar, Ebrahim
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS). Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Pirhashemi, Mahsa
    Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
    Pozina, Galia
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Liu, Xianjie
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Palisaitis, Justinas
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Pettersson, Håkan
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS). Department of Sciences and Technology, Linköping University, Norrköping, Sweden & Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Willander, Magnus
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Nur, Omer
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities2019Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, nr 52, s. 30585-30598Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    High-efficiency photocatalysts are crucial for the removal of organic pollutants and environmental sustainability. In the present work, we report on a new low-temperature hydrothermal chemical method, assisted by ultrasonication, to synthesize disruptive plasmonic ZnO/graphene/Ag/AgI nanocomposites for solar-driven photocatalysis. The plasmonic nanocomposites were investigated by a wide range of characterization techniques, confirming successful formation of photocatalysts with excellent degradation efficiency. Using Congo red as a model dye molecule, our experimental results demonstrated a photocatalytic reactivity exceeding 90% efficiency after one hour simulated solar irradiation. The significantly enhanced degradation efficiency is attributed to improved electronic properties of the nanocomposites by hybridization of the graphene and to the addition of Ag/AgI which generates a strong surface plasmon resonance effect in the metallic silver further improving the photocatalytic activity and stability under solar irradiation. Scavenger experiments suggest that superoxide and hydroxyl radicals are responsible for the photodegradation of Congo red. Our findings are important for the fundamental understanding of the photocatalytic mechanism of ZnO/graphene/Ag/AgI nanocomposites and can lead to further development of novel efficient photocatalyst materials. © 2019 Elsevier B.V.

  • 28.
    Savas, Süleyman
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Hardware/Software Co-Design of Heterogeneous Manycore Architectures2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In the era of big data, advanced sensing, and artificial intelligence, the required computation power is provided mostly by multicore and manycore architectures. However, the performance demand keeps growing. Thus the computer architectures need to continue evolving and provide higher performance. The applications, which are executed on the manycore architectures, are divided into several tasks to be mapped on separate cores and executed in parallel. Usually these tasks are not identical and may be executed more efficiently on different types of cores within a heterogeneous architecture. Therefore, we believe that the heterogeneous manycores are the next step for the computer architectures. However, there is a lack of knowledge on what form of heterogeneity is the best match for a given application or application domain. This knowledge can be acquired through designing these architectures and testing different design configurations. However, designing these architectures is a great challenge. Therefore, there is a need for an automated design method to facilitate the architecture design and design space exploration to gather knowledge on architectures with different configurations. Additionally, it is already difficult to program manycore architectures efficiently and this difficulty will only increase further with the introduction of heterogeneity due to the increase in the complexity of the architectures, unless this complexity is somehow hidden. There is a need for software development tools to facilitate the software development for these architectures and enable portability of the same software across different manycore platforms.

    In this thesis, we first address the challenges of the software development for manycore architectures. We evaluate a dataflow language (CAL) and a source-to-source compilation framework (Cal2Many) with several case studies in order to reveal their impact on productivity and performance of the software. The language supports task level parallelism by adopting actor model and the framework takes CAL code and generates implementations in the native language of several different architectures.

    In order to address the challenge of custom hardware development, we first evaluate a commercial manycore architecture namely Epiphany and identify its demerits. Then we study manycore architectures in order to reveal possible uses of heterogeneity in manycores and facilitate choice of architecture for software and hardware development. We define a taxonomy for manycore architectures that is based on the levels of heterogeneity they contain and discuss the benefits and drawbacks of these levels. We finally develop and evaluate a design method to design heterogeneous manycore architectures customized based on application requirements. The architectures designed with this method consist of cores with application specific accelerators. The majority of the design method is automated with software tools, which support different design configurations in order to increase the productivity of the hardware developer and enable design space exploration.

    Our results show that the dataflow language, together with the software development tool, decreases software development efforts significantly (25-50%), while having a small impact (2-17%) on the performance. The evaluation of the design method reveal that the performance of automatically generated accelerators is between 96-100% of the performance of their manually developed counterparts. Additionally, it is possible to increase the performance of the architectures by increasing the number of cores and using application specific accelerators, usually with a cost on the area usage. However, under certain circumstances, using accelerator may lead to avoiding usage of large general purpose components such as the floating-point unit and therefore improves the area utilization. Eventually, the final impact on the performance and area usage depends on the configurations. When compared to the Epiphany architecture, which is a commercial homogeneous manycore, the generated manycores show competitive results. We can conclude that the automated design method simplifies heterogeneous manycore architecture design and facilitates design space exploration with the use of configurable parameters.

  • 29.
    Fors, Vaike
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Pink, Sarah
    Monash University, Melbourne, Australia.
    Berg, Martin
    Malmö University, Malmö, Sweden.
    O'Dell, Tom
    Lund University, Lund, Sweden.
    Imagining Personal Data: Experiences of Self-Tracking2019 (uppl. 1)Bok (Refereegranskat)
    Abstract [en]

    Digital self-tracking devices and data have become normal elements of everyday life. Imagining Personal Data examines the implications of the rise of body monitoring and digital self-tracking for how we inhabit, experience and imagine our everyday worlds and futures. Through a focus on how it feels to live in environments where data is emergent, present and characterized by a sense of uncertainty, the authors argue for a new interdisciplinary approach to understanding the implications of self-tracking, which attends to its past, present and possible future. Building on social science approaches the book accounts for the concerns of scholars working in design, philosophy and human-computer interaction. It problematizes the body and senses in relation to data and tracking devices, presents an accessible analytical account of the sensory and affective experiences of self-tracking, and questions the status of big data. In doing so, the book proposes an agenda for future research and design that puts people at its centre.

  • 30.
    Krish, Ram P.
    et al.
    School of Electronic Engineering, Dublin City University, Ireland.
    Fierrez, Julian
    School of Engineering, Universidad Autonoma de Madrid, Spain.
    Ramos, Daniel
    School of Engineering, Universidad Autonoma de Madrid, Spain.
    Alonso-Fernandez, Fernando
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Improving Automated Latent Fingerprint Identification Using Extended Minutia Types2019Ingår i: Information Fusion, ISSN 1566-2535, E-ISSN 1872-6305, Vol. 50, s. 9-19Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Latent fingerprints are usually processed with Automated Fingerprint Identification Systems (AFIS) by law enforcement agencies to narrow down possible suspects from a criminal database. AFIS do not commonly use all discriminatory features available in fingerprints but typically use only some types of features automatically extracted by a feature extraction algorithm. In this work, we explore ways to improve rank identification accuracies of AFIS when only a partial latent fingerprint is available. Towards solving this challenge, we propose a method that exploits extended fingerprint features (unusual/rare minutiae) not commonly considered in AFIS. This new method can be combined with any existing minutiae-based matcher. We first compute a similarity score based on least squares between latent and tenprint minutiae points, with rare minutiae features as reference points. Then the similarity score of the reference minutiae-based matcher at hand is modified based on a fitting error from the least square similarity stage. We use a realistic forensic fingerprint casework database in our experiments which contains rare minutiae features obtained from Guardia Civil, the Spanish law enforcement agency. Experiments are conducted using three minutiae-based matchers as a reference, namely: NIST-Bozorth3, VeriFinger-SDK and MCC-SDK. We report significant improvements in the rank identification accuracies when these minutiae matchers are augmented with our proposed algorithm based on rare minutiae features. © 2018 Elsevier B.V.

  • 31.
    Pirasteh, Parivash
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Pashami, Sepideh
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Löwenadler, Magnus
    Aftermarket Solutions Department, Volvo Trucks, Gothenburg, Sweden.
    Thunberg, Klas
    Service Market Products, Volvo Buses, Gothenburg, Sweden.
    Ydreskog, Henrik
    Aftermarket Solutions Department, Volvo Trucks, Gothenburg, Sweden.
    Berck, Peter
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Interactive feature extraction for diagnostic trouble codes in predictive maintenance: A case study from automotive domain2019Ingår i: Proceedings of the Workshop on Interactive Data Mining, New York, NY: Association for Computing Machinery (ACM), 2019, artikel-id 4Konferensbidrag (Refereegranskat)
    Abstract [en]

    Predicting future maintenance needs of equipment can be addressed in a variety of ways. Methods based on machine learning approaches provide an interesting platform for mining large data sets to find patterns that might correlate with a given fault. In this paper, we approach predictive maintenance as a classification problem and use Random Forest to separate data readouts within a particular time window into those corresponding to faulty and non-faulty component categories. We utilize diagnostic trouble codes (DTCs) as an example of event-based data, and propose four categories of features that can be derived from DTCs as a predictive maintenance framework. We test the approach using large-scale data from a fleet of heavy duty trucks, and show that DTCs can be used within our framework as indicators of imminent failures in different components.

  • 32.
    Aein, Mohamad Javad
    et al.
    Department for Computational Neuroscience at the Bernstein Center Göttingen (Inst. of Physics 3) & Leibniz Science Campus for Primate Cognition, Georg-August-Universität Göttingen, Göttingen, Germany.
    Aksoy, Eren
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Wörgötter, Florentin
    Department for Computational Neuroscience at the Bernstein Center Göttingen (Inst. of Physics 3) & Leibniz Science Campus for Primate Cognition, Georg-August-Universität Göttingen, Göttingen, Germany.
    Internet Provisioning in VANETs: Performance Modeling of Drive-Thru Scenarios2019Ingår i: The international journal of robotics research, ISSN 0278-3649, E-ISSN 1741-3176, Vol. 38, nr 8, s. 910-934Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Drive-thru-Internet is a scenario in cooperative intelligent transportation systems (C-ITSs), where a road-side unit (RSU) provides multimedia services to vehicles that pass by. Performance of the drive-thru-Internet depends on various factors, including data traffic intensity, vehicle traffic density, and radio-link quality within the coverage area of the RSU, and must be evaluated at the stage of system design in order to fulfill the quality-of-service requirements of the customers in C-ITS. In this paper, we present an analytical framework that models downlink traffic in a drive-thru-Internet scenario by means of a multidimensional Markov process: the packet arrivals in the RSU buffer constitute Poisson processes and the transmission times are exponentially distributed. Taking into account the state space explosion problem associated with multidimensional Markov processes, we use iterative perturbation techniques to calculate the stationary distribution of the Markov chain. Our numerical results reveal that the proposed approach yields accurate estimates of various performance metrics, such as the mean queue content and the mean packet delay for a wide range of workloads. © 2019 IEEE.

  • 33.
    Evdokimova, Ekaterina
    et al.
    Department of Telecommunications and Information, Ghent University, Gent, Belgium.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). Department of Electrical Engineering, Western Norway University of Applied Sciences, Bergen, Norway.
    Lyamin, Nikita
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Fiems, Dieter
    Department of Telecommunications and Information, Ghent University, Gent, Belgium.
    Internet Provisioning in VANETs: Performance Modeling of Drive-Thru Scenarios2019Ingår i: IEEE transactions on intelligent transportation systems (Print), ISSN 1524-9050, E-ISSN 1558-0016, s. 1-15Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Drive-thru-Internet is a scenario in cooperative intelligent transportation systems (C-ITSs), where a road-side unit (RSU) provides multimedia services to vehicles that pass by. Performance of the drive-thru-Internet depends on various factors, including data traffic intensity, vehicle traffic density, and radio-link quality within the coverage area of the RSU, and must be evaluated at the stage of system design in order to fulfill the quality-of-service requirements of the customers in C-ITS. In this paper, we present an analytical framework that models downlink traffic in a drive-thru-Internet scenario by means of a multidimensional Markov process: the packet arrivals in the RSU buffer constitute Poisson processes and the transmission times are exponentially distributed. Taking into account the state space explosion problem associated with multidimensional Markov processes, we use iterative perturbation techniques to calculate the stationary distribution of the Markov chain. Our numerical results reveal that the proposed approach yields accurate estimates of various performance metrics, such as the mean queue content and the mean packet delay for a wide range of workloads. © 2019 IEEE.

  • 34.
    Ribeiro, Eduardo
    et al.
    University of Salzburg, Salzburg, Austria & Federal University of Tocantins, Palmas, Brazil.
    Uhl, Andreas
    University of Salzburg, Salzburg, Austria.
    Alonso-Fernandez, Fernando
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Iris Super-Resolution using CNNs: is Photo-Realism Important to Iris Recognition?2019Ingår i: IET Biometrics, ISSN 2047-4938, E-ISSN 2047-4946, Vol. 8, nr 1, s. 69-78Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of low-resolution images adopting more relaxed acquisition conditions such as mobile phones and surveillance videos is becoming increasingly common in Iris Recognition nowadays. Concurrently, a great variety of single image Super-Resolution techniques are emerging, specially with the use of convolutional neural networks. The main objective of these methods is to try to recover finer texture details generating more photo-realistic images based on the optimization of an objective function depending basically on the CNN architecture and the training approach. In this work, we explore single image Super-Resolution using CNNs for iris recognition. For this, we test different CNN architectures as well as the use of different training databases, validating our approach on a database of 1.872 near infrared iris images and on a mobile phone image database. We also use quality assessment, visual results and recognition experiments to verify if the photo-realism provided by the CNNs which have already proven to be effective for natural images can reflect in a better recognition rate for Iris Recognition. The results show that using deeper architectures trained with texture databases that provide a balance between edge preservation and the smoothness of the method can lead to good results in the iris recognition process. © The Institution of Engineering and Technology 2015

  • 35.
    Lien, Shao-Yu
    et al.
    National Chung Cheng University, Chia-Yi, Taiwan.
    Kuo, Yen-Chih
    National Formosa University, Yulin, Taiwan.
    Deng, Der-Jiunn
    National Changhua University of Education, Changhua, Taiwan.
    Tsai, Hua-Lung
    Industrial Technology Research Institute, Hsinchu, Taiwan.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Benslimane, Abderrahim
    University of Avignon, Avignon, France.
    Latency-Optimal mmWave Radio Access for V2X Supporting Next Generation Driving Use Cases2019Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 7, s. 6782-6795Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With the facilitation of the fifth generation (5G) New Radio (NR), Vehicle-to-Everything (V2X) applications have entered a brand new era to sustain the next generation driving use cases of advanced driving, vehicle platooning, extended sensors and remote driving. To deploy these driving use cases, the service requirements however include low latency, high reliability, and high data rates, which thus render utilizing millimeter wave (mmWave) carriers (spectrum above 6 GHz) as a remedy to empower the next generation driving use cases. However, suffering from severe signal attenuation, transmission range of mmWave carriers may be very limited, which is unfavorable in mobile network deployment to offer seamless services, and compel directional transmission/reception using beamforming mandatory. For this purpose, both a transmitter and a receiver should sweep their beams toward different directions over time, and a communication link can be established only if a transmitter and a receiver arrange their beam directions toward each other at the same time (known as beam alignment). Unfortunately, latency of performing beam sweeping to achieve beam alignment turns out the be a dominating challenge to exploit mmWave, especially for the next generation driving use cases. In this paper, we consequently derive essential principles and designs for beam sweeping at the transmitter side and receivers side, which not only guarantee the occurrence of beam alignment but also optimize the latency to achieve beam alignment. Based on the availabilities of a common geographic reference and the knowledge of beam sweeping scheme at the transmitter side, we derive corresponding performance bounds in terms of latency to achieve beam alignment, and device corresponding latency-optimal beam sweeping schemes. The provided engineering insights therefore pave inevitable foundations to practice the next generation driving use cases using mmWave carriers.

  • 36.
    Bocharova, Irina
    et al.
    St.-Petersburg University of Information Technologies, Mechanics and Optics, St.-Petersburg, Russia & University of Tartu, Tartu, Estonia.
    Kudryashov, Boris
    St.-Petersburg University of Information Technologies, Mechanics and Optics, St.-Petersburg, Russia & University of Tartu, Tartu, Estonia.
    Lyamin, Nikita
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Frick, Erik
    AstaZero Hällered, Sandhult, Sweden.
    Rabi, Maben
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). Department of Electrical Engineering, Western Norway University of Applied Sciences, Bergen, Norway.
    Low Delay Inter-Packet Coding in Vehicular Networks2019Ingår i: Future Internet, ISSN 1999-5903, E-ISSN 1999-5903, Vol. 11, nr 12, artikel-id 212Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In Cooperative Intelligent Transportation Systems (C-ITSs), vehicles need to wirelessly connect with Roadside units (RSUs) over limited durations when such point-to-point connections are possible. One example of such communications is the downloading of maps to the C-ITS vehicles. Another example occurs in the testing of C-ITS vehicles, where the tested vehicles upload trajectory records to the roadside units. Because of real-time requirements, and limited bandwidths, data are sent as User Datagram Protocol (UDP) packets. We propose an inter-packet error control coding scheme that improves the recovery of data when some of these packets are lost; we argue that the coding scheme has to be one of convolutional coding. We measure performance through the session averaged probability of successfully delivering groups of packets. We analyze two classes of convolution codes and propose a low-complexity decoding procedure suitable for network applications. We conclude that Reed–Solomon convolutional codes perform better than Wyner–Ash codes at the cost of higher complexity. We show this by simulation on the memoryless binary erasure channel (BEC) and channels with memory, and through simulations of the IEEE 802.11p DSRC/ITS-G5 network at the C-ITS test track AstaZero.

  • 37.
    Ashfaq, Awais
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Halland Hospital, Region Halland, Halmstad, Sweden.
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Machine learning in healthcare - a system’s perspective2019Ingår i: Proceedings of the ACM SIGKDD Workshop on Epidemiology meets Data Mining and Knowledge Discovery (epiDAMIK) / [ed] B. Aditya Prakash, Anil Vullikanti, Shweta Bansal, Adam Sadelik, Arlington, 2019, s. 14-17Konferensbidrag (Refereegranskat)
    Abstract [en]

    A consequence of the fragmented and siloed healthcare landscape is that patient care (and data) is split along multitude of different facilities and computer systems and enabling interoperability between these systems is hard. The lack interoperability not only hinders continuity of care and burdens providers, but also hinders effective application of Machine Learning (ML) algorithms. Thus, most current ML algorithms, designed to understand patient care and facilitate clinical decision-support, are trained on limited datasets. This approach is analogous to the Newtonian paradigm of Reductionism in which a system is broken down into elementary components and a description of the whole is formed by understanding those components individually. A key limitation of the reductionist approach is that it ignores the component-component interactions and dynamics within the system which are often of prime significance in understanding the overall behaviour of complex adaptive systems (CAS). Healthcare is a CAS.

    Though the application of ML on health data have shown incremental improvements for clinical decision support, ML has a much a broader potential to restructure care delivery as a whole and maximize care value. However, this ML potential remains largely untapped: primarily due to functional limitations of Electronic Health Records (EHR) and the inability to see the healthcare system as a whole. This viewpoint (i) articulates the healthcare as a complex system which has a biological and an organizational perspective, (ii) motivates with examples, the need of a system's approach when addressing healthcare challenges via ML and, (iii) emphasizes to unleash EHR functionality - while duly respecting all ethical and legal concerns - to reap full benefits of ML.

  • 38.
    Varshosaz, Mahsa
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Luthmann, Lars
    Technische Universität Darmstadt, Darmstadt, Germany.
    Mohr, Paul
    Technische Universität Darmstadt, Darmstadt, Germany.
    Lochau, Malte
    Technische Universität Darmstadt, Darmstadt, Germany.
    Mousavi, Mohammad Reza
    University of Leicester, Leicester, United Kingdom.
    Modal Transition System Encoding of Featured Transition Systems2019Ingår i: The Journal of logical and algebraic methods in programming, ISSN 2352-2208, E-ISSN 2352-2216, Vol. 106, s. 1-28Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Featured transition systems (FTSs) and modal transition systems (MTSs) are two of the most prominent and well-studied formalisms for modeling and analyzing behavioral variability as apparent in software product line engineering. On one hand, it is well-known that for finite behavior FTSs are strictly more expressive than MTSs, essentially due to the inability of MTSs to express logically constrained behavioral variability such as persistently exclusive behaviors. On the other hand, MTSs enjoy many desirable formal properties such as compositionality of semantic refinement and parallel composition. In order to finally consolidate the two formalisms for variability modeling, we establish a rigorous connection between FTSs and MTSs by means of an encoding of one FTS into an equivalent set of multiple MTSs. To this end, we split the structure of an FTS into several MTSs whenever it is necessary to denote exclusive choices that are not expressible in a single MTS. Moreover, extra care is taken when dealing with infinite behaviour: loops may have to be unrolled to accumulate FTS path constraints when encoding them into MTSs. We prove our encoding to be semanticpreserving (i.e., the resulting set of MTSs induces, up to bisimulation, the same set of derivable variants as their FTS counterpart) and to commute with modal refinement. We further give an algorithm to calculate a concise representation of a given FTS as a minimal set of MTSs. Finally, we present experimental results gained from applying a tool implementation of our approach to a collection of case studies.

  • 39.
    Mostowski, Wojciech
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Model-based fault injection for testing gray-box systems2019Ingår i: The Journal of logical and algebraic methods in programming, ISSN 2352-2208, E-ISSN 2352-2216, Vol. 103, s. 31-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Motivated by applications in the automotive domain, particularly the Autosar basic software standard, we present a technique to improve model-based testing by allowing model-level fault injections. These models are plugged into a larger system as executable components to test it for general tolerance to slightly varying, possibly faulty components or library implementations. Such model execution is possible through applying an automated mocking mechanism and model cross-referencing. Systematic modelling and testing is possible by having comprehensive fault models which both simulate faults and guide the model-based testing procedure towards quicker discovery of these faults. We show the principles of our method on an illustrative example and discuss how it is implemented in a commercial model-based testing tool QuickCheck and applied to a more realistic case study. More generally, this work explores multi-purpose (or meta) modelling – an approach where one parametric model is used for different test targets, like functional testing or safety testing.

  • 40.
    Varshosaz, Mahsa
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Modeling and Model-Based Testing of Software Product Lines2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Software product line (SPL) engineering has become common practice for mass production and customization of variability intensive systems. A software product line comprises a family of software systems which share a managed core set of artifacts and also have a set of well-defined variabilities. The main idea in SPL engineering is to enable systematic reuse in different phases of software development to reduce cost and time to release.

    Model-Based Testing (MBT) is a technique that is widely used for quality assurance of software systems. In MBT, an abstract model, which captures the desired behavior of the system, is used to generate test cases. The test cases are executed against a real implementation of the system and the conformance between the implementation and the specification is checked by comparing the observed outputs with the ones prescribed by the model.

    Software product lines have been applied in a number of domains with mission critical systems. MBT is one of the techniques that has been used for analysis of such systems. As the number of products can be potentially large in an SPL, using conventional approaches for MBT of the products of an SPL individually can be very costly and time consuming. To tackle this problem, several approaches have been proposed in order to enable systematic reuse in different phases of the MBT process.

    An efficient modeling technique is the first step towards an efficient MBT technique for SPLs. So far, several formalisms have been proposed for modeling SPLs. In this thesis, we conduct a study on such modeling techniques, focusing on four fundamental formalisms, namely featured transition systems, modal transition systems, product line calculus of communicating systems, and 1- selecting modal transition systems. We compare the expressive power and the succinctness of these formalisms.

    Furthermore, we investigate adapting existing MBT methods for efficient testing of SPLs. As a part of this line of our research, we adapt the test case generation algorithm of one of the well-known black-box testing approaches, namely, Harmonized State Identification (HSI) method by exploiting the idea of delta-oriented programming. We apply the adapted test case generation algorithm to a case study taken from industry and the results show up to 50 percent reduction of time in test case generation by using the delta-oriented HSI method.

    In line with our research on investigating existing MBT techniques, we compare the relative efficiency and effectiveness of the test case generation algorithms of the well-known Input-Output Conformance (ioco) testing approach and the complete ioco which is another testing technique used for input output transition systems that guarantees fault coverage. The comparison is done using three case studies taken from the automotive and railway domains. The obtained results show that complete ioco is more efficient in detecting deep faults (i.e., the faults reached through longer traces) in large state spaces while ioco is more efficient in detecting shallow faults (i.e., the faults reached through shorter traces) in small state spaces.

    Moreover, we conduct a survey on sampling techniques, which have been proposed as a solution for handling the large number of products in analysis. In general, in product sampling a subset of products that collectively cover the behavior of the product line are selected. Performing tests on well selected sample set can reveal most of the faults in all products. We provide a classification for a catalog of studies on product sampling for software product lines. Additionally, we present a number of insights on the studied work as well as gaps for the future research.

  • 41.
    Bocharova, Irina
    et al.
    ITMO University, Saint Petersburg, Russia & University of Tartu, Tartu, Estonia.
    Kudryashov, Boris
    ITMO University, Saint Petersburg, Russia & University of Tartu, Tartu, Estonia.
    Rabi, Maben
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Lyamin, Nikita
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Dankers, Wouter
    Volvo GTT, Göteborg, Sweden.
    Frick, Erik
    AstaZero, Hällered, Sweden.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Modeling Packet Losses in Communication Networks2019Ingår i: 2019 IEEE International Symposium on Information Theory: Proceedings, 2019, s. 1012-1016Konferensbidrag (Refereegranskat)
    Abstract [en]

    An approach to constructing discrete models of packet losses suitable for a wide variety of communication network applications is studied. It is based on estimating parameters of probabilistic automata described via so-called pseudo-Markov chains. The new technique is applied both to approximating a discrete time analog process at the output of known channel models and to the experimental data stream. Comparison of models is performed by computing probabilities of more than m losses out of n transmitted packets (P (m, n)). It is shown that for the Rician fading channel with exponential correlation and correlation determined by a Bessel filter, the obtained rank-two and rank-three discrete modes, respectively, provide high accuracy coincidence of P (m, n) performances. The rank-three discrete model computed on the experimental data stream obtained from the LTE network provides significantly better approximation of P (≥ m, n) performance than that obtained by the Baum-Welch algorithm.

  • 42.
    Karimi, Mohammad
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab). Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Heurlin, Magnus
    Solid State Physics and NanoLund, Lund University, Lund, Sweden & Sol Voltaics AB, Lund, Sweden.
    Limpert, Steven
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Jain, Vishal
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS). Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Mansouri, Ebrahim
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Zeng, Xulu
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Samuelson, Lars
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Linke, Heiner
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Borgström, Magnus T.
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Pettersson, Håkan
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Tillämpad matematik och fysik (MPE-lab).
    Nanowire photodetectors with embedded quantum heterostructures for infrared detection2019Ingår i: Infrared physics & technology, ISSN 1350-4495, E-ISSN 1879-0275, Vol. 96, s. 209-212Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanowires offer remarkable opportunities for realizing new optoelectronic devices because of their unique fundamental properties. The ability to engineer nanowire heterostructures with large bandgap variations is particularly interesting for technologically important broadband photodetector applications. Here we report on infrared photodetectors based on arrays of InP nanowires with embedded InAsP quantum discs. We demonstrate a strongly reduced dark current in the detector elements by compensating the unintentional n-doping in the nominal intrinsic region of the InP nanowires by in-situ doping with Zn, a crucial step towards realizing high-performance devices. The optimized array detectors show a broad spectral sensitivity at normal incidence for wavelengths from visible to far-infrared up to 20 μm, promoted by both interband and intersubband transitions. Optical simulations show that the unexpected normal incidence response at long wavelengths is due to non-zero longitudinal modes hosted by the nanowires. © 2018 Elsevier B.V.

  • 43.
    Hylving, Lena
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Bygstad, Bendik
    University of Oslo, Oslo, Norway.
    Nuanced Responses to Enterprise Architecture Management: Loyalty, Voice, and Exit2019Ingår i: Journal of Management Information Systems, ISSN 0742-1222, E-ISSN 1557-928X, Vol. 36, nr 1, s. 14-36Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Enterprise Architecture Management (EAM) aims to deal with the complex- ities of information technology (IT) solutions and to achieve more organizational agility. EAM is a holistic approach to IT architecture, but the results of the approach have been variable. An under-researched aspect of EAM is how different organizational units respond to the call for a holistic approach. In this study, we investigate how different stakeholders in a large governmental agency connected to three on-going projects and their response to EAM initiatives. With a qualitative approach, we identify three options of response to EAM initiatives: (1) active compliance with the EAM strategy, (2) loyal but passive response, and (3) rebel solutions. We argue for the need of a more nuanced repertoire of actions for dealing with EAM and show how these responses are useful for understanding and managing successful EAM.

  • 44.
    Campolo, Claudia
    et al.
    DIIES Department, University Mediterranea of Reggio Calabria, Italy.
    Molinaro, Antonella
    DIIES Department, University Mediterranea of Reggio Calabria, Italy & CentraleSupélec/L2S, Université Paris-Saclay, France.
    Berthet, Antoine
    CentraleSupélec/L2S, Université Paris-Saclay, France.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES). Department of Electrical Engineering, Western Norway University of Applied Sciences, Bergen, Norway.
    On Latency and Reliability of Road Hazard Warnings over the Cellular V2X Sidelink Interface2019Ingår i: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Decentralized Environmental Notification Messages (DENMs) are generated by a vehicle upon detection of an accident or other hazards on the road, and need to be promptly and reliably transmitted. Delayed or lost messages may have fatal consequences, especially in critical driving situations, such as automated overtake and emergency braking, when vehicles can be very close to each other. In this letter, the DENM latency and reliability performances are characterized over the Cellular Vehicle-to-everything (C-V2X) sidelink (PC5 interface). The conducted study uses analytical tools, among which stochastic geometry, to derive performance results, then validated by simulations. Results are applied to the case of DENMs for emergency electronic brake lights, and helpful insights are provided for this crucial case and for other more general DENM-assisted V2X use cases.

  • 45.
    Lyamin, Nikita
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Performance evaluation of safety critical ITS-G5 V2V communications for cooperative driving applications2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Intelligent Transport Systems (ITS) are aiming to provide innovative services related to different modes of transport and traffic management, and enable various users to be better informed and make safer, more coordinated and smarter use of transport networks. Cooperative-ITS (C-ITS) support connectivity between vehicles, vehicles and roadside infrastructure, traffic signals as well as with other road users. In order to enable vehicular communications European Telecommunication Standards Institute (ETSI) delivered ITS-G5 -- a of set of C-ITS standards. Considering the goals of C-ITS, inter-vehicle communications should be reliable and efficient.

    The subject of this thesis is evaluation of the performance, efficiency, and dependability of ITS-G5 communications for cooperative driving applications support. This thesis includes eight scientific papers and extends the research area in three directions: evaluation of the performance of ITS-G5 beaconing protocols; studying the performance of ITS-G5 congestion control mechanisms; and studying the radio jamming Denial-of-Service (DoS) attacks and their detection methods.

    First, an overview of currently available and ongoing standardization targeting communications in C-ACC/platooning cooperative driving applications is provided. Then, as part of the first research direction, we demonstrate via a number of studies, that the adaptive beaconing approach where message generation is coupled to the speed variation of the originating ITS-s may lead to a message synchronization effect in the time domain when vehicles follow mobility scenarios that involve cooperative speed variation. We explain in detail the cause of this phenomenon and test it for a wide range of parameters. In relation to the second problem, we, first, study the influence of different available ITS-G5 legitimate setups on the C-ACC/platooning fuel efficiency and demonstrate that proper communication setup may enhance fuel savings. Then we thoroughly study the standardization of the congestion control mechanism for ITS-G5, which will affect the operation of all cooperative driving C-ITS applications as a mandatory component. We study the influence of congestion control on application performance and give recommendations for improvement to make the congestion control to target at optimizing the applications performance metrics. In the scope of the last research direction, we propose two real-time jamming DoS detection methods. The main advantage of our detection techniques is their short learning phase that not exceed a few seconds and low detection delay of a few hundreds of milliseconds. Under some assumptions, the proposed algorithms demonstrates the ability to detect certain types of attacks with high detection probability.

  • 46.
    Muhammad, Naveed
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Åstrand, Björn
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Predicting Agent Behaviour and State for Applications in a Roundabout-Scenario Autonomous Driving2019Ingår i: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, nr 19, artikel-id 4279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As human drivers, we instinctively employ our understanding of other road users' behaviour for enhanced efficiency of our drive and safety of the traffic. In recent years, different aspects of assisted and autonomous driving have gotten a lot of attention from the research and industrial community, including the aspects of behaviour modelling and prediction of future state. In this paper, we address the problem of modelling and predicting agent behaviour and state in a roundabout traffic scenario. We present three ways of modelling traffic in a roundabout based on: (i) the roundabout geometry; (ii) mean path taken by vehicles inside the roundabout; and (iii) a set of reference trajectories traversed by vehicles inside the roundabout. The roundabout models are compared in terms of exit-direction classification and state (i.e., position inside the roundabout) prediction of query vehicles inside the roundabout. The exit-direction classification and state prediction are based on a particle-filter classifier algorithm. The results show that the roundabout model based on set of reference trajectories is better suited for both the exit-direction and state prediction.

  • 47.
    Ashfaq, Awais
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Predicting clinical outcomes via machine learning on electronic health records2019Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The rising complexity in healthcare, exacerbated by an ageing population, results in ineffective decision-making leading to detrimental effects on care quality and escalates care costs. Consequently, there is a need for smart decision support systems that can empower clinician's to make better informed care decisions. Decisions, which are not only based on general clinical knowledge and personal experience, but also rest on personalised and precise insights about future patient outcomes. A promising approach is to leverage the ongoing digitization of healthcare that generates unprecedented amounts of clinical data stored in Electronic Health Records (EHRs) and couple it with modern Machine Learning (ML) toolset for clinical decision support, and simultaneously, expand the evidence base of medicine. As promising as it sounds, assimilating complete clinical data that provides a rich perspective of the patient's health state comes with a multitude of data-science challenges that impede efficient learning of ML models. This thesis primarily focuses on learning comprehensive patient representations from EHRs. The key challenges of heterogeneity and temporality in EHR data are addressed using human-derived features appended to contextual embeddings of clinical concepts and Long-Short-Term-Memory networks, respectively. The developed models are empirically evaluated in the context of predicting adverse clinical outcomes such as mortality or hospital readmissions. We also present evidence that, surprisingly, different ML models primarily designed for non-EHR analysis (like language processing and time-series prediction) can be combined and adapted into a single framework to efficiently represent EHR data and predict patient outcomes.

  • 48.
    Ashfaq, Awais
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab). Halland Hospital, Region Halland, Sweden.
    Pinheiro Sant'Anna, Anita
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Lingman, Markus
    Halland Hospital, Region Halland, Sweden & Institute of Medicine, Dept. of Molecular and Clinical Medicine/Cardiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Readmission prediction using deep learning on electronic health records2019Ingår i: Journal of Biomedical Informatics, ISSN 1532-0464, E-ISSN 1532-0480, Vol. 97, artikel-id 103256Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Unscheduled 30-day readmissions are a hallmark of Congestive Heart Failure (CHF) patients that pose significant health risks and escalate care cost. In order to reduce readmissions and curb the cost of care, it is important to initiate targeted intervention programs for patients at risk of readmission. This requires identifying high-risk patients at the time of discharge from hospital. Here, using real data from over 7,500 CHF patients hospitalized between 2012 and 2016 in Sweden, we built and tested a deep learning framework to predict 30-day unscheduled readmission. We present a cost-sensitive formulation of Long Short-Term Memory (LSTM) neural network using expert features and contextual embedding of clinical concepts. This study targets key elements of an Electronic Health Record (EHR) driven prediction model in a single framework: using both expert and machine derived features, incorporating sequential patterns and addressing the class imbalance problem. We show that the model with all key elements achieves a higher discrimination ability (AUC 0.77) compared to the rest. Additionally, we present a simple financial analysis to estimate annual savings if targeted interventions are offered to high risk patients. © 2019 The Authors

  • 49.
    Lyamin, Nikita
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Kleyko, Denis
    Department of Computer Science, Electrical and Space Engineering, Computer Science, Luleå University of Technology, Luleå, Sweden.
    Delooz, Quentin
    Center of Automotive Research on Integrated Safety Systems and Measurement Area (CARISSMA), Ingolstadt, Germany.
    Vinel, Alexey
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Real-time jamming DoS detection in safety-critical V2V C-ITS using data mining2019Ingår i: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 23, nr 3, s. 442-445Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A data mining-based method for real-time detection of radio jamming Denial-of-Service (DoS) attacks in IEEE 802.11p vehicle-to-vehicle (V2V) communications is proposed. The method aims at understanding the reasons for losses of periodic cooperative awareness messages (CAM) exchanged by vehicles in a platoon. Detection relies on a knowledge of IEEE 802.11p protocols rules as well as on historical observation of events in the V2V channel. In comparison to the state-of-the-art method, the proposed method allows operating under the realistic assumption of random jitter accompanying every CAM transmission. The method is evaluated for two jamming models: random and ON-OFF. 

  • 50.
    Mashad Nemati, Hassan
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Pinheiro Sant'Anna, Anita
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Nowaczyk, Sławomir
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Jürgensen, Jan Henning
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Hilber, Patrik
    KTH Royal Institute of Technology, Stockholm, Sweden.
    Reliability Evaluation of Power Cables Considering the Restoration Characteristic2019Ingår i: International Journal of Electrical Power & Energy Systems, ISSN 0142-0615, E-ISSN 1879-3517, Vol. 105, s. 622-631Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper Weibull parametric proportional hazard model (PHM) is used to estimate the failure rate of every individual cable based on its age and a set of explanatory factors. The required information for the proposed method is obtained by exploiting available historical cable inventory and failure data. This data-driven method does not require any additional measurements on the cables, and allows the cables to be ranked for maintenance prioritization and repair actions.

    Furthermore, the results of reliability analysis of power cables are compared when the cables are considered as repairable or non-repairable components. The paper demonstrates that the methods which estimate the time-to-the-first failure (for non-repairable components) lead to incorrect conclusions about reliability of repairable power cables.

    The proposed method is used to evaluate the failure rate of each individual Paper Insulated Lead Cover (PILC) underground cables in a distribution grid in the south of Sweden. © 2018 Elsevier Ltd

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