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  • Linde, Peter
    Blekinge Institute of Technology, The Library.
    Årsberättelse 2017 Högskolebiblioteket BTH2018Other (Other (popular science, discussion, etc.))
  • Public defence: 2018-03-20 10:00 J1650, Karlskrona
    Usman, Muhammad
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Improving Expert Estimation of Software Development Effort in Agile Contexts2018Doctoral thesis, comprehensive summary (Other academic)
  • Usman, Muhammad
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Petersen, Kai
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Börstler, Jürgen
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Neto, Pedro
    bFederal University of Piaui , BRA.
    Developing and Using Checklists to Improve Software Effort Estimation: a Multi-Case StudyManuscript (preprint) (Other academic)
  • Sievert, Thomas
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mathematics and Natural Sciences.
    Rasch, Joel
    Molflow, Gothenburg, SWE.
    Carlström, Anders
    RUAG Space AB, SWE.
    Pettersson, Mats
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mathematics and Natural Sciences.
    Analysis of reflections in GNSS radio occultation measurements using the phase matching amplitude2018In: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 11, p. 569-580Article in journal (Refereed)
    Abstract [en]

    It is well-known that in the presence of super-refractive layers in the lower-tropospheric inversion of GNSSradio occultation (RO) measurements using the Abel trans-form yields biased refractivity profiles. As such it is problem-atic to reconstruct the true refractivity from the RO signal.Additional information about this lower region of the atmo-sphere might be embedded in reflected parts of the signal. Toretrieve the bending angle, the phase matching operator canbe used. This operator produces a complex function of theimpact parameter, and from its phase we can calculate thebending angle. Instead of looking at the phase, in this paperwe focus on the function’s amplitude. The results in this pa-per show that the signatures of surface reflections in GNSSRO measurements can be significantly enhanced when usingthe phase matching method by processing only an appropri-ately selected segment of the received signal. This signatureenhancement is demonstrated by simulations and confirmedwith 10 hand-picked MetOp-A occultations with reflectedcomponents. To validate that these events show signs of re-flections, radio holographic images are generated. Our resultssuggest that the phase matching amplitude carries informa-tion that can improve the interpretation of radio occultationmeasurements in the lower troposphere.

  • Georgsson, Mattias
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Toward Patient-centered, Standardized, and Reproducible Approaches of Evaluating the Usability of mHealth Chronic Disease Self-management Systems for Diabetes2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Diabetes is a chronic disease affecting 422 million patients worldwide according to World Health Organization data with 30.3 million in the United States and 64 million in Europe. The prevalence speaks to the need for improved ways to support patients in disease self-management. mHealth solutions are increasingly used for this; however, usability is a current challenge affecting patients’ mHealth use. Recent literature emphasizes an increased focus on patient-centeredness in diabetes care, user-centeredness in chronic disease mHealth system design and standardized, systematic approaches for usability evaluation. The aim of this thesis and its individual studies was to incorporate these foci into the evaluation of two mobile health self-management systems for diabetes.

    Study I used ISO standard 9241-11 to examine the relationship between selected group characteristics of diabetes patients on specific interaction outcomes to quantitatively identify needed system modifications. Study II utilized a multi-method design to assess diabetes patients’ mHealth usage and combined two novel analytic methods to structure and analyze results. Study III used a modified, user-oriented heuristic evaluation (HE) method, validated tasks and in-depth severity factor ratings to identify critical problems from patients’ point of view. By developing and employing a modified, user-centered cognitive walkthrough method (UC-CW), study IV assessed its effectiveness and efficiency in finding relevant usability problems for users as well as patients’ acceptance. The modified CW was validated against the golden-standard user test with Think Aloud.

    Study I emphasized the importance of considering user characteristics in mHealth performance as these influenced interaction outcomes. All patients had difficulties with multiple-step tasks. Patients more recently diagnosed were able to perform tasks more successfully, with fewer errors and at faster times and had higher satisfaction scores; similar outcomes to the more experienced users. Educational level did not, however, seem to influence performance. In study II, the usability test with Think-Aloud (TA), in-depth interviews and questionnaires contributed to 19 consolidated issues, and triangulated on 5 critical usability problems for users. The combined analysis methods resulted in structured, categorized descriptions to aid in problem-solving. In Study III, the disease-related, critical information deficiencies found by expert evaluators using the modified, structured method also converged on and highlighted potentially adverse user concerns. Study IV demonstrated that the UC-CW found more critical user problems compared to the user test with TA despite both methods producing similar major average severity ratings and violations of heuristic categories. The modified method was more efficient per detected problem and experienced as less cognitively demanding and with a higher ease of use.

    These studies offer different approaches that include patient-centered, efficient and user-acceptable methods and method modifications to detect critical usability issues for users. Importantly, improved mHealth designs for users could mean improvement in interactions, interaction performance, increased adoption, and long-term perhaps even increased adherence to interventions for chronic conditions.

  • Tutschku, Kurt
    Institute of Computer ScienceUniversity of Würzburg, DEU.
    A Measurement-based Traffic Profile of the eDonkey Filesharing Service2004Conference paper (Refereed)
    Abstract [en]

    Peer-to-peer file sharing applications have evolved to one of the major traffic sources in the Internet. In particular, the eDonkey file sharing system and its derivatives are causing high amounts of traffic volume in today’s networks. The eDonkey system is typically used for exchanging very large files like audio/video CDs or even DVD images. In this report we provide a measurement based traffic profile of the eDonkey service. Furthermore, we discuss how this type of service increases the ”mice and elephants” phenomenon in the Internet traffic characteristics.

  • Stezenbach, David
    et al.
    University of Vienna, AUT.
    Tutschku, Kurt Tutschku
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    A Performance Evaluation Metric for NFV Elements on Multiple Timescales2013In: Proceeding of the Global Communications Conference 2013 (GLOBECOM 2013)., 2013Conference paper (Refereed)
    Abstract [en]

    Todays virtualization technologies are manifold and a comparison is hardly achievable. Thus, a metric independent from the virtualization technology is required to compare different systems. The metric is measurable in a passive way, hence, no artificial traffic has to be generated, and the virtualization system needs not to be modified. It evaluates the throughput of events on different time slices. This methodology, in contrast to existing jitter evaluations, enables the identification of critical timescales in the virtualization system. In this demonstration a proof-of-concept for a performance metric for NFV elements on multiple timescales is presented. In a reduced environment consisting of a single virtual router host the influences of hardware resource sharing and other impact factors (e.g. cpu, memory or disc load) are made visible. The demonstration gives an example of a performance degrease on smaller timescales, which can not be identified by a common throughput measurement over time. Thus, the presented metric enables to identify critical system conditions and can be used to optimize the scheduling of NFV, to compare different virtualization technologies, or to grade the performance for specific applications.

  • Tutschku, Kurt Tutschku
    et al.
    Universität Wien, AUT.
    Zinner, Thomas
    University of Wuerzburg.
    Nakao, Akihiro
    University of Tokyo.
    Tran-Gia, Phuoc
    University of Wuerzburg.
    Network Virtualization: Implementation Steps Towards the Future Internet.2009In: Workshop on Overlay and Network Virtualization at KIVS 2009, 2009Conference paper (Refereed)
    Abstract [en]

    In this paper we will investigate why and how Network Virtualization (NV) can overcome the shortfalls of the current system and how it paves the way for the Future Internet. Therefore, we will first discuss some major deficiencies and achievements of today’s Internet. Afterwards, we identify three major building blocks of NV: a) the use of application-specific routing overlays, b) the safe consolidation of resources by OS virtualization on a generic infrastructure, and c) the exploitation of the network diversity for performance enhancements and for new business models, such as the provisioning of intermediate nodes or path oracles. Subsequently, we discuss an implementation scheme for network virtualization or routing overlays based on one-hop source routers (OSRs). The capabilities of the combination of NV and OSRs are demonstrated by a concurrent multipath transmission (CMP) mechanism (also known as stripping) for obtaining high throughput transmission pipes. The suggested stripping mechanism constitutes a first instance of a refinement of the concept of NV, the idea of transport system virtualization.

  • Llewellyn, Tim
    et al.
    nVISO SA, CHE.
    Milagro Fernández Carrobles, María del
    University of Castilla-La Mancha, ESP.
    Deniz, Oscar
    University of Castilla-La Mancha, ESP.
    Fricker, Samuel
    i4Ds Centre for Requirements Engineering, CHE.
    Storkey, Amos
    University of Edinburgh, GBR.
    Pazos, Nuria
    Haute Ecole Specialisee de Suisse, CHE.
    Velikic, Gordana
    RT-RK, SRB.
    Leufgen, Kirsten
    Dahyot, Rozenn
    Trinity College Dublin, IRL.
    Koller, Sebastian
    Technical University Munich, DEU.
    Goumas, Georgios
    Technical University of Athens, GRC.
    Leitner, Peter
    SYNYO GmbH, AUT.
    Dasika, Ganesh
    ARM Ltd., GBR.
    Wang, Lei
    ZF Friedrichshafen AG, DEU.
    Tutschku, Kurt
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    BONSEYES: Platform for Open Development of Systems of Artificial Intelligence2017Conference paper (Other academic)
    Abstract [en]

    The Bonseyes EU H2020 collaborative project aims to develop a platform consisting of a Data Marketplace, a Deep Learning Toolbox, and Developer Reference Platforms for organizations wanting to adopt Artificial Intelligence. The project will be focused on using artificial intelligence in low power Internet of Things (IoT) devices ("edge computing"), embedded computing systems, and data center servers ("cloud computing"). It will bring about orders of magnitude improvements in efficiency, performance, reliability, security, and productivity in the design and programming of systems of artificial intelligence that incorporate Smart Cyber-Physical Systems (CPS). In addition, it will solve a causality problem for organizations who lack access to Data and Models. Its open software architecture will facilitate adoption of the whole concept on a wider scale. To evaluate the effectiveness, technical feasibility, and to quantify the real-world improvements in efficiency, security, performance, effort and cost of adding AI to products and services using the Bonseyes platform, four complementary demonstrators will be built. Bonseyes platform capabilities are aimed at being aligned with the European FI-PPP activities and take advantage of its flagship project FIWARE. This paper provides a description of the project motivation, goals and preliminary work.

  • Börstler, Jürgen
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Störrle, Harald
    QAware GmbH, DEU.
    Toll, Daniel
    Linné University, SWE.
    van Assema, Jelle
    University of Amsterdam, NLD.
    Duran, Rodrigo
    Aalto University, FIN.
    Hooshangi, Sara
    George Washington University, USA.
    Jeuring, Johan
    Utrecht University, NLD.
    Keuning, Hieke
    Windesheim University of Applied Sciences, NLD.
    Kleiner, Carsten
    University of Applied Sciences & Arts Hannover, DEU.
    MacKellar, Bonnie
    St John’s University, USA.
    “I know it when I see it”: Perceptions of Code Quality2017In: ITiCSE '17 Proceedings of the 2017 ACM Conference on Innovation and Technology in Computer Science Education, ACM Digital Library, 2017, p. 389-399Conference paper (Refereed)
    Abstract [en]

    Context. Code quality is a key issue in software development. The ability to develop high quality software is therefore a key learning goal of computing programs. However, there are no universally accepted measures to assess the quality of code and current standards are considered weak. Furthermore, there are many facets to code quality. Defining and explaining the concept of code quality is therefore a challenge faced by many educators.

    Objectives. In this working group, we investigated code quality as perceived by students, educators, and professional developers, in particular, the differences in their views of code quality and which quality aspects they consider as more or less important. Furthermore, we investigated their sources for information about code quality and its assessment.

    Methods. We interviewed 34 students, educators and professional developers regarding their perceptions of code quality. For the interviews they brought along code from their own experience to discuss and exemplify code quality.

    Results. There was no common definition of code quality among or within these groups. Quality was mostly described in terms of indicators that could measure an aspect of code quality. Among these indicators, readability was named most frequently by all groups. The groups showed significant differences in the sources they use for learning about code quality with education ranked lowest in all groups.

    Conclusions. Code quality should be discussed more thoroughly in educational programs.

  • Niyizamwiyitira, Christine
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Performance Aspects of Databases and Virtualized Real-time Applications2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Context: High computing system performance depends on the interaction between software and hardware layers in modern computer systems. Two strong trends that effect different layers in computer systems are that single processors are now more or less completely replaced by multiprocessors, which are often organized into clusters, and virtualization of resources. The performance evaluation of different software on such physical and virtualized resources, is the focus of this thesis.

    Objectives: The objectives of this thesis are to investigate the performance evaluation of SQL and No SQL database management systems, namely Cassandra, CouchDB, MongoDB, PostgreSQL, and RethinkDB; and soft real-time application namely, voice-driven web. Scheduling algorithms for resource allocation for hard real-time applications on virtual processor are also investigated.

    Methods: Experiment is used to measure the performance of SQL and No SQL management systems on cluster. It is also used to develop a prototype and predicts processor performance of voice-driven web on multiprocessors. Theoretical methods are used to model and design algorithms to schedule real-time applications on the virtual processor machine. Simulation is used to quantify the performance implications of certain parameter values in our theoretical results and to compare expected performance with theoretical bounds in our schedulability tests.

    Results:The performance of Cassandra, CouchDB, MongoDB, 2

    PostgreSQL, and RethinkDB is evaluated in terms of writing and reading throughput and latencies in cluster computing. For reading throughput, all database systems are horizontally scalable as the cluster’s nodes number increases, however, only Cassandra and couchDB exhibit scalability for data writing. The overall evaluation shows that Cassandra has the most writing scalable throughput as the number of nodes increases with a relative low latency, whereas PostgreSQL has the lowest writing latency, and MongoDB has the lowest reading latency.

    The architectures’ tradeoffs of voice-driven web show that the voice engine should be installed on the server instead of being on the mobile device, and performance evaluations show that speech engine scales with respect to the number of cores in the multiprocessor with and without hyperthreading.

    The thesis presents scheduling techniques for real-time applications that runs in virtual machines which are time sharing the processor. Each virtual machine’s period and execution time that allow real-time applications to meet their deadlines can be defined using these techniques. Simulation results show the impact of the length of different VM periods with respect to overhead. The tradeoffs between resources consumption and period length are also given. Furthermore, a utilization based test for scheduling real-time application on virtual multiprocessor is presented. This test determines if a task set is schedulable or not. If the task set is schedulable the algorithm provides the priority for each task. This algorithm avoids Dhall’s effect, which may cause task sets with even very low utilization to miss deadlines.

    Conclusions: The thesis presented the performance evaluation of reading and writing throughput and latencies for SLQ and NoSQL management systems in the cluster computing. The thesis quantifies the tradeoffs of voice-driven web architectures and the performance scalability of the speech engine with respect to number of cores of the multiprocessor. Furthermore, this thesis proposes scheduling algorithms for real-time 3

    application with hard deadline on virtual processors, either as a single core processor or as a multicore processor.

  • Sievert, Thomas
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mathematics and Natural Sciences.
    Pettersson, Mats
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mathematics and Natural Sciences.
    Vu, Viet Thuy
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mathematics and Natural Sciences.
    Rasch, Joel
    Molflow, SWE.
    Anders, Carlström
    RUAG Space AB, SWE.
    Determining the refractivity at the bottom of the atmosphere using radio occultation2017In: 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), IEEE, 2017, p. 4433-4436Conference paper (Refereed)
    Abstract [en]

    High accuracy of impact height is important to get reliableRadio Occultation (RO) measurements of the atmosphere refractivity.We have made an investigation on how accuratelywe can measure the impact height at ground level using waveoptics simulations, realistic refractivity profiles, a realisticsimulator for an advanced RO instrument including noise,and using phase matching for the inversion. The idea of theinvestigation is to increase the measurement accuracy of impactheight at low altitudes and to give reliable measurementseven in cases of super-refractive layers. We present statisticson the accuracy and precision of the determination of theimpact height at ground, as well as the resulting accuracy andprecision in the measured refractivity.

  • Nordahl, Christian
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Persson, Marie
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Grahn, Håkan
    Blekinge Institute of Technology, Faculty of Computing, Department of Computer Science and Engineering.
    Detection of Residents' Abnormal Behaviour by Analysing Energy Consumption of Individual Households2017In: Proceedings of the 17th IEEE International Conference on Data Mining Workshops (ICDMW), IEEE, 2017, p. 729-738Conference paper (Refereed)
    Abstract [en]

    As average life expectancy continuously rises, assisting the elderly population with living independently is of great importance. Detecting abnormal behaviour of the elderly living at home is one way to assist the eldercare systems with the increase of the elderly population. In this study, we perform an initial investigation to identify abnormal behaviour of household residents using energy consumption data. We conduct an experiment in two parts, the first to identify a suitable prediction algorithm to model energy consumption behaviour, and the second to detect abnormal behaviour. This approach allows for an initial step for the elderly care that has a low cost, is easily deployable, and is non-intrusive.

  • Sun, Bin
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Cheng, Wei
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Goswami, Prashant
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Bai, Guohua
    Blekinge Institute of Technology, Faculty of Computing, Department of Creative Technologies.
    Short-Term Traffic Forecasting Using Self-Adjusting k-Nearest Neighbours2018In: IET Intelligent Transport Systems, ISSN 1751-956X, E-ISSN 1751-9578, Vol. 12, no 1, p. 41-48Article in journal (Refereed)
    Abstract [en]

    Short-term traffic forecasting is becoming more important in intelligent transportation systems. The k-nearest neighbours (kNN) method is widely used for short-term traffic forecasting.However, kNN parameters self-adjustment has been a problem due to dynamic traffic characteristics. This paper proposes a fully automatic dynamic procedure kNN (DP-kNN) that makes the kNN parameters self-adjustable and robust without predefined models or training. We used realworld data with more than one-year traffic records to conduct experiments. The results show that DP-kNN can perform better than manually adjusted kNN and other benchmarking methods with regards to accuracy on average. This study also discusses the difference between holiday and workday traffic prediction as well as the usage of neighbour distance measurement.

  • Olofsdotter Bergström, Annika
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Elovaara, Pirjo
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    8 women 8 rules2017In: Libro de Actas V Congresso Internacional Cidades Criativas / [ed] Alves, Luis M; Alves, P y García García, F, Porto: ICONO14 , 2017, p. 525-526Conference paper (Refereed)
    Abstract [en]

    8 women in a dark Nordic winter forest, playing around with flashlights, accompanied by the echoing of a world famous Arabic singer from their mobile phones-

    what has this to do with creative and playful cities?


    This forest expedition was a part of a non-traditional participatory research and action project from southeastern Sweden. The project provides the empirical material for our reflective story. The overall aim of the project was to investigate, through playful explorations, how a diverse group of women can transform for us unfamiliar places, both concerning geographical, cultural, social aspects, and also how places in themselves can transform people. Ultimately the project also challenged the notion of citizenship not as a legal term but as an active and ongoing becoming. The core group of the project was created by academic scholars, municipality and a number of female immigrants from Syria.


    When we started to plan the project we were in need of theoretical guides that could support us in our playfulness, without losing the critical and situated understanding of our trajectory and hence we identified some key concepts provided by our epistemological companions, such as:  caring (de la Bellacasa, 2012), touching/becoming (de la Bellacasa, 2009), messiness (Law, 2004). To meet up these approaches we had to rely on and develop methods that could enable the exploratory playfulness; therefore, we turned to the artistic movements of Situationists and Surrealists.


    These choices demanded a sensitive awareness towards ourselves, each other and the places. We locate this project as a transdisciplinary framework of site-specific games, participatory design and feminist research.

  • Johnsson, Mikael
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    How Understanding of Agile Innovation Work Affects Innovation Teams2017Conference paper (Refereed)
    Abstract [en]

     This research aims to explore how the understanding of agile innovation work methodologies affect innovation teams and the progress of innovation projects. In a long-term research, three innovation teams were studied through questionnaires, interviews, audio-recorded interviews and rich notes from. The data was analysed using group development theories and knowledge taxonomy to determine the relation of the teams' estimated knowledge and their performance in relation to the teams’ group development status. The results indicate that innovation teams that are unfamiliar with agile innovation work tend to not seek collaboration due to uncertainty, which results in slow progress. When an innovation team’s surrounding organisation is unfamiliar with agile innovation methodologies it tends to not offer their support until the innovation team can prove progress, also slowing the progress down. The opposite is noticed when innovation teams and the organisation understands how to apply agile innovation work methodologies, collaboration occurs easily, resulting in positive progress. Further research is suggested.

  • Johnsson, Mikael
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering. 1972.
    Innovation Enablers for Innovation Teams - A Review2017In: Journal of Innovation Management, ISSN 1000-324X, E-ISSN 2183-0606, Vol. 5, no 3, p. 75-121Article in journal (Refereed)
    Abstract [en]

    This review consolidates research on innovation enablers for

    innovation teams, defined within this research as factors that enable a crossfunctional

    team within an organization to conduct innovation work, to provide a

    deeper understanding of what factors enable innovation teams to conduct

    innovation work, which means that this research involves three areas to provide

    a holistic picture: the organizational context, the team itself, and the individuals

    within the innovation team. A systematic database search was conducted in

    which 208 relevant articles were identified and analyzed thematically way.

    Twenty innovation enablers related to innovation teams were identified:

    awareness, capabilities, climate, collaboration, culture, dedication, economy,

    education, empowerment, entre- / intrapreneurship, human resources,

    incentives, knowledge, knowledge management, management, mind-set, need,

    processes, strategy, and time. This review contributes to prior research a deeper

    understanding of what key factors enable innovative work for innovation teams.

    Suggestions of both academic and practical use for the identified innovation

    enablers are included in this review, and direction for future research is