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  • 1.
    Ahonen-Jonnarth, Ulla
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Odelstad, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Simulation as a tool for the evaluation of forest management treatments2010In: ESM'2010 - The 2010 European Simulation and Modelling Conference / [ed] Gerrit K. Janssens, Katrien Ramaekers and An Caris, Ghent: EUROSIS-ETI , 2010, p. 426-433Conference paper (Refereed)
    Abstract [en]

    Cleaning of young forest stands is a multicriteria problem with conflicting goals. This kind of forest management treatment is performed by human beings but it is possible that this work may be performed by artificial agents in the future. The artificial agents need detailed information about how to clean a forest stand and/or what are the goals for cleaning. One problem in development of cleaning rules for artificial cleaning agents is that explicit knowledge about good cleaning results is not detailed. In this paper we present a tool for developing and testing rules and judging evaluation functions for cleaning. We illustrate this tool by presenting examples of some ways to clean forest stands in a computer environment and we present how the cleaning results can be evaluated. In order to obtain material for experiments it is also possible to simulate forest stands using this tool.

  • 2.
    Andrée, Martin
    et al.
    Lantmäteriet.
    Larsson, Karolina
    KLM; Stockholms stad.
    Nordqvist Darell, Fanny
    Stockholms stad.
    Malm, Linus
    Tyréns.
    Tullberg, Odd
    WSP.
    Wallberg, Ann
    JM.
    Norsell, Johan
    NAI Svefa.
    Paasch, Jesper M.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Paulsson, Jenny
    Kungliga Tekniska Högskolan, Stockholm.
    Slutrapport för projektet Smart planering för byggande: Delprojekt 3 - BIM som informationsstöd för 3D fastighetsbildning2018Report (Other academic)
    Abstract [sv]

    Samhällsbyggnadsprocessen behöver utvecklas och bli smartare, öppnare och mer effektiv för ett ökat bostadsbyggande. En digitalisering av samhällsbyggnadsprocessen kan ge ett effektivare samarbete mellan kommun, fastighetsägare, byggherrar, medborgare, näringsliv och myndigheter.Vid bildande av tredimensionellt avgränsade fastigheter eller fastighetsutrymmen (3D-fastigheter) behöver gränsernas läge redovisas både verbalt och i kartor och ritningar, detsamma gäller berörda rättigheter. Det är idag ofta svårt att korrekt redovisa en 3D-volym med enbart dagens pappersritningar och även svårt att läsa en registerkarta i 2D med fastigheter och rättigheter beslutade i 3D. Beslutsunderlagen i fastighetsbildnings-processen behöver bli mer enhetliga och entydiga samt fastighetsinformationen behöver bli återanvändningsbar i hela samhällsbyggnadsprocessen.I detta projekt har vi studerat informationsbehovet i de olika tidpunkterna under fastighetsbildningsprocessen för 3D-fastigheter med fokus på vem som är ansvarig för att tillhandahålla informationsunderlag för att identifiera krav på utformning av 3D-modeller (t.ex BIM) och 3D-stöd för fastighetsbildning.Internationellt finns det ett stort intresse och många frågeställningar gällande samspelet mellan BIM och Fastighetsinformation; det är däremot ganska få fall som har identifierats där man har arbetat praktiskt med BIM i relation till redovisning av 3D-fastigheter.Projektethar även tittat på behov av visualisering och tillhandahållande av fastighetsinformation i 3D, hur informationen bör utformas för att kunna tolkas korrekt samt nyttjas vidare av andra aktörer i samhällsbyggnadsprocessen.Slutsatsen i projektetär att en framtida arbetsmodell där man i samband med myndighetsutövningen för fastighetsbildning samverkar med stöd av BIM och geografisk information i ärendehandläggningen kan ge stora effekter på både myndighetens effektivitet och i ärendeutövningen och för förståelsen av fastighetbildningsbeslutet hos samtliga intressenter i processen. För att det arbete som genomförts i denna utredning skall få genomslag i den dagliga verksamheten rekommenderar vibland annatatt de statliga och kommunala lantmäterimyndigheterna arbetar vidare med att utveckla arbetsprocessen och rekommendationerna för 3D-fastighetsbildning baserat på resultatet från detta projekt och redan i dagens modell efterfrågar att man i handläggningsprocessen kan arbeta BIM-baserat även om kommande beslutshandlingar under en övergångsperiod fortfarande kommer att vara baserade på ritningsbilagor i 2D.

  • 3.
    Andrée, Martin
    et al.
    Lantmäteriet.
    Paasch, Jesper M.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Paulsson, Jenny
    Kungliga Tekniska Högskolan.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    BIM and 3D property visualisation2018In: FIG Congress 2018: Proceedings, 2018, article id 9367Conference paper (Other academic)
    Abstract [en]

    The concept of 3D property has only existed a short period of time in Sweden, being introduced in 2004 and expanded in 2009 by the addition of condominium (apartment) ownership. It is therefore a rather new form of land management, and the demand for 3D property formation has not been as high as initially expected. There is however an increased interest in 3D property and ownership apartments today, also as being part of the nation’s geospatial infrastructure together with related 3D information for e.g. buildings, utility networks and other features. An effective management of 3D property is depending on, among other things, visualization, representation and storage of 3D real property data, such as legal boundaries and real property rights. There are at present a number of ongoing 3D development and research projects focusing on visualization and standardization of 3D cadastral boundaries. They are part of the national "Smart Built Environment" development and research program, which includes the use of BIM in the (future) 3D property formation process with focus on visualization of 3D real property and condominiums, and specification of requirements and evaluation of 3D digital real property information created and managed in the processes.

    This paper presents the preliminary results of the working group on visualization of 3D boundaries in the project "Smart planning, construction and management processes throughout the life cycle". The aim is to test the results produced in the project "Information for planning, real property formation and building permission", working group "BIM for 3D property formation." The purpose of this working group is to set the requirements for and evaluate the test bed for 3D property information. The focus is on visualization of 3D property and ownership apartments. The proposed model for digitization and visualization of 3D property formation will be tested in a test bed environment. A pilot case from the Stockholm area is then used in the test bed to see how it could work in practice.

    The expected outcome is recommendations for the exchange of documentation and other digital information in 3D processes, the visualization of legal boundaries for stakeholders, registration of legal 3D objects in the Swedish national real property register and how to communicate 3D models to right holders/stakeholders for 3D property and condominiums and the property market, as well as suggestions for a homogeneous, effective and digital flow of 3D information to be used by actors and other stakeholders in the property formation, planning and building processes.

  • 4.
    Aslani, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Mesgari, Mohammad Saadi
    Division of Visual Information and Interaction, Department of Information Technology, Uppsala University, Uppsala, Sweden.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Faculty of Geodesy and Geomatics Engineering, K.N. Toosi University of Technology, Tehran, Iran.
    Wiering, Marco
    Institute of Artificial Intelligence and Cognitive Engineering, University of Groningen, Groningen, Netherlands.
    Developing adaptive traffic signal control by actor-critic and direct exploration methods2018In: Proceedings of the Institution of Civil Engineers: Transport, ISSN 0965-092X, E-ISSN 1751-7710, article id jtran.17.00085Article in journal (Refereed)
    Abstract [en]

    Designing efficient traffic signal controllers has always been an important concern in traffic engineering. This is owing to the complex and uncertain nature of traffic environments. Within such a context, reinforcement learning has been one of the most successful methods owing to its adaptability and its online learning ability. Reinforcement learning provides traffic signals with the ability automatically to determine the ideal behaviour for achieving their objective (alleviating traffic congestion). In fact, traffic signals based on reinforcement learning are able to learn and react flexibly to different traffic situations without the need of a predefined model of the environment. In this research, the actor-critic method is used for adaptive traffic signal control (ATSC-AC). Actor-critic has the advantages of both actor-only and critic-only methods. One of the most important issues in reinforcement learning is the trade-off between exploration of the traffic environment and exploitation of the knowledge already obtained. In order to tackle this challenge, two direct exploration methods are adapted to traffic signal control and compared with two indirect exploration methods. The results reveal that ATSC-ACs based on direct exploration methods have the best performance and they consistently outperform a fixed-time controller, reducing average travel time by 21%.

  • 5.
    Aslani, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Faculty of Geodesy and Geomatics Engineering, K.N. Toosi University of Technology, Tehran, Iran.
    Mohammad Saadi, Mesgari
    Division of Visual Information and Interaction, Department of Information Technology, Uppsala University, Uppsala, Sweden.
    Wiering, Marco A.
    Institute of Artificial Intelligence and Cognitive Engineering, University of Groningen, Groningen, Netherlands.
    Traffic signal optimization through discrete and continuous reinforcement learning with robustness analysis in downtown Tehran2018In: Advanced Engineering Informatics, ISSN 1474-0346, E-ISSN 1873-5320, Vol. 38, p. 639-655Article in journal (Refereed)
    Abstract [en]

    Traffic signal control plays a pivotal role in reducing traffic congestion. Traffic signals cannot be adequately controlled with conventional methods due to the high variations and complexity in traffic environments. In recent years, reinforcement learning (RL) has shown great potential for traffic signal control because of its high adaptability, flexibility, and scalability. However, designing RL-embedded traffic signal controllers (RLTSCs) for traffic systems with a high degree of realism is faced with several challenges, among others system disturbances and large state-action spaces are considered in this research.

    The contribution of the present work is founded on three features: (a) evaluating the robustness of different RLTSCs against system disturbances including incidents, jaywalking, and sensor noise, (b) handling a high-dimensional state-action space by both employing different continuous state RL algorithms and reducing the state-action space in order to improve the performance and learning speed of the system, and (c) presenting a detailed empirical study of traffic signals control of downtown Tehran through seven RL algorithms: discrete state Q-learning(λ" role="presentation">), SARSA(λ" role="presentation">), actor-critic(λ" role="presentation">), continuous state Q-learning(λ" role="presentation">), SARSA(λ" role="presentation">), actor-critic(λ" role="presentation">), and residual actor-critic(λ" role="presentation">).

    In this research, first a real-world microscopic traffic simulation of downtown Tehran is carried out, then four experiments are performed in order to find the best RLTSC with convincing robustness and strong performance. The results reveal that the RLTSC based on continuous state actor-critic(λ" role="presentation">) has the best performance. In addition, it is found that the best RLTSC leads to saving average travel time by 22% (at the presence of high system disturbances) when it is compared with an optimized fixed-time controller.

  • 6.
    Aslani, Mohammad
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Division of Visual Information and Interaction, Department of Information Technology, Uppsala University, Uppsala, Sweden.
    Wiering, Marco
    Institute of Artificial Intelligence and Cognitive Engineering, University of Groningen, Groningen, the Netherlands.
    Continuous residual reinforcement learning for traffic signal control optimization2018In: Canadian journal of civil engineering (Print), ISSN 0315-1468, E-ISSN 1208-6029, Vol. 45, no 8, p. 690-702Article in journal (Refereed)
    Abstract [en]

    Traffic signal control can be naturally regarded as a reinforcement learning problem. Unfortunately, it is one of the most difficult classes of reinforcement learning problems owing to its large state space. A straightforward approach to address this challenge is to control traffic signals based on continuous reinforcement learning. Although they have been successful in traffic signal control, they may become unstable and fail to converge to near-optimal solutions. We develop adaptive traffic signal controllers based on continuous residual reinforcement learning (CRL-TSC) that is more stable. The effect of three feature functions is empirically investigated in a microscopic traffic simulation. Furthermore, the effects of departing streets, more actions, and the use of the spatial distribution of the vehicles on the performance of CRL-TSCs are assessed. The results show that the best setup of the CRL-TSC leads to saving average travel time by 15% in comparison to an optimized fixed-time controller.

  • 7.
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    A Student Perspective on Software Development and Maintenance2010Report (Other academic)
    Abstract [en]

    How do Computer Science students view Software Development and Software Maintenance? To answer this question, a Phenomenographic perspective was chosen, and 20 Swedish students at four universities were interviewed.

    The interviews were analyzed to find in which different ways the informants, on collective level, see the phenomena of interest. The resulting outcome spaces show that software development is described in a number of qualitatively different ways reaching from problem solving, design and deliver, design for the future and then a more comprehensive view that includes users, customers, budget and other aspects. Software maintenance is described as correcting bugs, making additions, adapting to new requirements from the surroundings, and something that is a natural part of the job.

    Finally, conclusions from the results and additional observations are discussed in terms of their implications for teaching, and some suggestions for practical use are given.

  • 8.
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    On the Road to a Software Profession: Students' Experiences of Concepts and Thresholds2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Research has shown that there are gaps in knowledge between newly hired and experienced professionals and that some of these gaps are related to concepts, such as the concepts of object orientation. This problem, and the fact that most computer science majors want to work in the software industry, leads to questions regarding why these gaps exist and how students can be better prepared for their future careers. Against this background, this thesis addresses two theme-based perspectives that focus on students' views of concepts in Computer Science.

    The first theme-based perspective investigated the existence of potential Threshold Concepts in Computer Science. Such concepts should be troublesome, transformative, irreversible, and integrative. Qualitative methods have been mainly used and empirical data have been collected through semi-structured interviews, concept maps, and written stories. The results identified two Threshold Concepts, suggested several more, and then described the ways in which these concepts have transformed students.

    The second theme-based perspective took a phenomenographic approach to find the variation in how students understand concepts related to the software profession. Data were collected via semi-structured interviews. In one study the interviews were held in connection with role-playing where students took on the role of a newly hired programmer. The results show a variety of ways to experience the addressed phenomena in the student collective, ranging from superficial views that often have a practical nature to more sophisticated understandings that reflect a holistic approach, including a professional point of view.

    Educators can use the results to emphasize concepts that are important from students' perspectives. The phenomenographic outcome spaces can help teachers to reflect upon their own ways of seeing contrasted with student conceptions. I have indicated how variation theory can be applied to open more sophisticated ways of seeing, which in this context stresses the professional aspects to help students prepare for becoming professional software developers.

  • 9.
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Students' different understandings of class diagrams2012In: Computer Science Education, ISSN 0899-3408, E-ISSN 1744-5175, Vol. 22, no 1, p. 29-62Article in journal (Refereed)
    Abstract [en]

    The software industry needs well-trained software designers and one important aspect of software design is the ability to model softwaredesigns visually and understand what visual models represent. However, previous research indicates that software design is a difficulttask to many students. This article reports empirical findings from aphenomenographic investigation on how students understand classdiagrams, Unified Modeling Language (UML) symbols, and relationsto object-oriented (OO) concepts. The informants were 20 Computer Science students from four different universities in Sweden. The results show qualitatively different ways to understand and describe UML class diagrams and the ‘‘diamond symbols’’ representing aggregation and composition. The purpose of class diagrams was understood in a varied way, from describing it as a documentation to a more advanced view related to communication. The descriptions of class diagrams varied from seeing them as a specification of classes to a more advanced view, where they were described to show hierarchic structures of classes and relations. The diamond symbols were seen as ‘‘relations’’ and a more advanced way was seeing the white and theblack diamonds as different symbols for aggregation and composition. As a consequence of the results, it is recommended that UML should be adopted in courses. It is briefly indicated how the phenomenographic results in combination with variation theory can be used by teachers to enhance students’ possibilities to reach advanced understanding of phenomena related to UML classdiagrams. Moreover, it is recommended that teachers should put more effort in assessing skills in proper usage of the basic symbols and models and students should be provided with opportunities to practise collaborative design, e.g. using whiteboards.

  • 10.
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Ways to Understand Class Diagrams2010Report (Other academic)
    Abstract [en]

    The software industry needs well trained software designers and one important aspect of software design is the ability to model software designs visually and understand what visual models represent. However, previous research indicates that software design is a difficult task to many students. This paper reports empirical findings from a phenomenographic investigation on how students understand class diagrams, UML symbols and relations to object oriented concepts. The informants were 20 Computer Science students from four different universities in Sweden.

    The results show qualitively different ways to understand and describe UML class diagrams and the "diamond symbols" representing aggregation and composition. The purpose of class diagrams was understood in a varied way, from describing it as a documentation to a more advanced view related to communication. The descriptions of class diagrams varied from seeing them as a specification of classes to a more advanced view where they were described to show hierarchic structures of classes and relations. The diamond symbols were seen as "relations" and a more advanced way was seeing the white and the black diamonds as different symbols for aggregation and composition.

    As a consequence of the results, it is recommended that UML should be adopted in courses. It is briefly indicated how the phenomenographic results in combination with variation theory can be used by teachers to enhance students' possibilities to reach advanced understanding of phenomena related to UML class diagrams. Moreover, it is recommended that teachers should put more effort in assessing skills in proper using of the basic symbols and models, and students should get many opportunities to practise collaborative design, e.g., using whiteboards.

  • 11.
    Boustedt, Jonas
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Eckerdal, Anna
    Uppsala Universitet.
    McCartney, Robert
    University of Connecticut, Storrs, CT, USA.
    Sanders, Kate
    Rhode Island College, Providence, RI, USA.
    Thomas, Lynda
    Aberystwyth University, Aberystwyth, Wales, UK.
    Zander, Carol
    University of Washington Bothell, Bothell, WA, USA .
    Students' perceptions of the differences between formal and informal learning2011In: ICER '11 Proceedings of the seventh international workshop on Computing education research / [ed] Kate Sanders, Michael Caspersen, Alison Clear, New York, USA: Association for Computing Machinery (ACM), 2011, p. 61-68Conference paper (Refereed)
    Abstract [en]

    Research has shown that most learning in the workplace takes place outside of formal training and, given the swiftly changing nature of the field, computer science graduates more than most workers, need to be able to learn computing topics outside of organized classes.

    In this paper we discuss students' perceptions of the difference between formal and informal learning of computing topics, based on three datasets: essays collected from a technical writing course at a single university; the results of a brainstorming exercise conducted in the same course; and semi-structured interviews conducted at six institutions in three countries.

    The students report strengths and weaknesses in informal learning. On the one hand, they are motivated, can choose their level of learning, can be more flexible about how they learn, and often retain the material better. On the other hand, they perceive that they may miss important aspects of a topic, learn in an ad hoc way, and have difficulty assessing their learning.

  • 12.
    Boustedt, Jonas
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    McCartney, Robert
    University of Connecticut, Storrs, CT, USA.
    Tenenberg, Josh
    University of Washington Tacoma, Tacoma, WA, USA.
    Cooper, Stephen
    Stanford University, Palo Alto, CA, USA.
    Garcia, Daniel, D.
    University of California Berkeley, Berkeley, CA, USA.
    Friend Hutton, Michelle
    Stanford University, Palo Alto, CA, USA.
    Parlante, Nick
    Stanford University, Palo Alto, CA, USA.
    Richards, Brad
    University of Puget Sound, Tacoma, WA, USA.
    It seemed like a good idea at the time2011In: SIGCSE'11: Proceedings of the 42nd ACM technical symposium on Computer science education, New York, NY, USA: ACM , 2011, p. 163-164Conference paper (Other academic)
    Abstract [en]

    We often learn of successful pedagogical experiments, but we seldom hear of the the ones that failed. For this special session we solicited submissions from the SIGCSE membership, selected the best from among these, and will have presentations at the session by the selected authors. Our contributions describe pedagogical approaches that seemed to be good ideas but turned out as failures. Contributors will describe their pedagogical experiment, the rationale for the experiment, evidence of failure, and lessons learned.

  • 13.
    Boustedt, Jonas
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    McCartney, Robert
    Department of Computer Science and Engineering, University of Connecticut, United States.
    Tenenberg, Josh
    Computing and Software Systems, University of Washington, Tacoma, WA, United States.
    Gehringer, F
    Department of Computer Science, North Carolina State University, United States.
    Lister, Raymond
    Faculty of Information Technology, University of Technology, Sydney, NSW, Australia.
    Musicant, Dave
    Department of Computer Science, Carleton College, United States.
    It seemed like a good idea at the time2010In: SIGCSE '10 : Proceedings of the 41th ACM technical symposium on Computer science education, New York: ACM , 2010, p. 558-559Conference paper (Other academic)
    Abstract [en]

    We often learn of successful pedagogical experiments, but we seldom hear of the the ones that failed. For this special session we solicited submissions from the SIGCSE membership, selected the best from among these, and will have presentations at the session by the selected authors. Our contributions describe pedagogical approaches that seemed to be good ideas but turned out as failures. Contributors will describe their pedagogical experiment, the rationale for the experiment, evidence of failure, and lessons learned.

  • 14.
    Davodi, Rashed
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Högberg, Jonatan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Radiobaserad spårning av rörlig utrustning inomhus2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 15.
    Edström, Viktoria
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Alternativa rutter med tidsbegränsning via en dubbelriktad modifiering av Dijkstra's algoritm2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    De flesta algoritmer som används för ruttplanering finner en ruttmellan en start- och slutposition. Ofta handlar det om att hitta denkortaste eller snabbaste rutten mellan positionerna. Denna studie hartill syfte att ta fram en metod som hittar flera lämpliga rutter mellantvå positioner med användning av Dijkstra ́s algoritm [2] ochdubbelriktad sökning. Med flera rutter får användaren möjlighet attvälja den rutt som passar bäst utifrån personliga preferenser. Tillexempel antalet stopp längs med rutten eller tidsåtgång för rutten.Den resulterande metoden tar fram ett antal rutter som är under ettvillkor gällande maximal tillåten tidsåtgång.

  • 16.
    Gutke Jonsson, Maria
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Kartläggning av navigationsenheters noggrannhet med hjälp av geovisualisering2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Utvecklingen av digital hälsa har bidragit till att flera aktörer är villiga att satsa på e-hälsa för förbättringar inom hälsovård, som t.ex. vid effektivisering och utbyte av patientinformation. I framtiden kan även utbyte av information mellan patienter och sjukvårdare, vid bedömning och kartläggning av patientens fysiska aktivitet, vara aktuellt. Syftet med studien är att utvärdera olika navigationsenheter i olika prisklasser samt redovisa deras pålitlighet vid påverkande faktorer. För analys och visualisering av resultatet tillämpades GIS.

    För studien samlades data in med hjälp av testpiloter. För utvärdering av navigationsenheterna utfördes 10 mätningar med mätinstrumentet GNSS RTK- nätverk i varierande terräng. Dessa mätpunkter fungerade som referenspunkter vid beräkning av avvikelse hos samtliga navigationsenheter. Resultatet av visualiseringen visar navigationsenheternas positionering och att påverkande faktorer kan kopplas till avvikelserna. Av resultatet kan navigationsenheternas noggrannhet visuellt avläsas i olika miljöförhållanden.

  • 17.
    Haglund, Johannes
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Tåneland, Fredrik
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Visualisering av en relationsdatabas: En fallstudie2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to explore what advantages could be found in using a three-dimensional visualization of a relation-database, rather than a more conventional means of visualization. This comparison needed two visualization-environments with interactivity capabilities, designed to ease handling customer and system relations for the Forestry Solutions department of CGI Gävle.

    First, a database was created, using a database-model that CGI provided, which included the structure of the internal relations between customers and systems in the database. This database was then filled with fictive data with corresponding structure, but not including potentially sensitive information. Then methods for gathering and inserting data into the database were created, for use by both solutions. This was crucial for the separation of the graphical interface and the underlying structure, which would keep the possibility to exchange the graphical portion of the system without affecting what lies underneath.

    The two visualization systems were then constructed in parallel, the 3D-system was mainly constructed in Unity, while the conventional system was constructed only using Visual Studio, for a Windows Forms application.

    The two systems were then tested by a few CGI employees with different internal roles, where they received a few tasks to complete, while being timed. This was then followed by an interview, where the test subjects had the opportunity to provide us with feedback to both systems design, implementation and which system they preferred using. They were also asked if they had any constructive feedback for further development, which led to us having a deeper understanding of what was necessary for a system of this purpose.

    This work concluded, based on tests, interview and studies that a three-dimensional visualization, if done correctly, would have great potential. We also concluded based on user feedback that combining both systems into one would have a positive impact on usability.

  • 18.
    Hast, Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Bengtsson, Lars
    Chalmers.
    Weidendorfer, Josef
    Tech Univ Munich, Munich, Germany.
    Wu, Ren
    HP Labs, Palo Alto, CA, USA.
    UCHPC 2010: Third workshop on unConventional high performance computing2011In: Euro-Par 2010 Parallel Processing Workshops: HeteroPar, HPCC, HiBB, CoreGrid, UCHPC, HPCF, PROPER, CCPI, VHPC, Ischia, Italy, August 31–September 3, 2010, Revised Selected Papers / [ed] Guarracino, MR; Vivien, F; Traff, JL; Cannataro, M; Danelutto, M; Hast, A; Perla, F; Knupfer, A; DiMartino, B; Alexander, M, Berlin: Springer Berlin/Heidelberg, 2011, p. 327-328Conference paper (Other academic)
  • 19.
    Hast, Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Ericsson, Martin
    UPPMAX, Uppsala University, Uppsala, Sweden .
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Multiscale Texture Synthesis and Colourization of Greyscale Textures2010In: 18th International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision, WSCG 2010 - In Co-operation with EUROGRAPHICS: Full Papers Proceedings, Plzen: Union Agency Science Press , 2010, p. 55-61Conference paper (Refereed)
    Abstract [en]

    The main idea presented herein is to use a multiscale texture synthesis approach in order to both colourize and upscale greyscale textures. Such textures can be vintage photos to be used in archaeological or urban 3D visualizations and obviously the colour needs to be reconstructed some way. Due to limited quality, walls etc in such 3D visualizations will appear either pixelized or blurry when the viewer approaches them on a close distance. The latter if some kind of interpolation technique is being used to reduce the pixelization. The low resolution greyscale texture and a high resolution coloured texture is used for the colourization and upscaling, which will produce a colour version of the greyscale texture with 4 times higher resolution in each upscale step. The novel idea is to use multiscale texture synthesis in HSV space for the first upscale in order to create a RGB colour image for subsequent upscaling, using either ordinary RGB multiscale texture synthesis or continue using HSV multiscale texture synthesis. These two main approaches will be compared and discussed.

  • 20.
    Hast, Anders
    et al.
    Uppsala universitet.
    Jenke, Peter
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Uppsala universitet.
    Shortest diagonal triangulation of convex layers2013In: Proceedings of the IASTED International Conference on Signal Processing, Pattern Recognition and Applications, SPPRA 2013, 2013, p. 424-430Conference paper (Refereed)
    Abstract [en]

    One problem in the field of computational geometry is the triangulation of convex layers. The rotating caliper algorithm is an alternative to the constrained Delaunay triangulation method. We present an improved triangulation algorithm, which gives a mesh quality close to that of the Constrained Delaunay but substantially faster. Each layer will be connected to the neighboring layer by edges and from the two vertices constituting an edge the proposed algorithm will select the shortest diagonal to its next neighbors in the polygonal chain on the other side, i.e. from the outer layer to the inner layer or vice versa. We discuss quality issues regarding the rotating caliper method and some improvements to it, as well as how a Constrained Delaunay can be efficiently implemented for convex layers.

  • 21.
    Hast, Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Marchetti, A
    Retrospective Illumination Correction of Greyscale Historical Aerial Photos2011In: Proceedings of International Conference on Image Analysis and Processing, 2011, p. 275-284Conference paper (Refereed)
  • 22.
    Hast, Anders
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Weidendorfer, Josef
    Tech Univ Munich, Munich, Germany.
    Weiss, Jan-Philipp
    Karlsruhe Inst Technol, Karlsruhe, Germany.
    UCHPC 2011: Fourth Workshop on UnConventional High Performance Computing2012In: EURO-PAR 2011: PARALLEL PROCESSING WORKSHOPS, PT II, Berlin: Springer Berlin/Heidelberg, 2012, p. 333-334Conference paper (Refereed)
  • 23.
    Hjelmblom, Magnus
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    State Transitions and Normative Positions within Normative Systems2011Report (Other academic)
    Abstract [en]

    Many multi-agent systems are naturally viewed as transition systems, in which the transitions between states are connected to the actions of the agents in the system. The behaviour of the individual agents can be regulated by a normative system in which norms are formulated in terms of permissible or prohibited state transitions. This report examines the set of types of such transitions, and their connection to different interpretations of the Kanger-Lindahl theory of normative positions. A refinement of Lindahl's system of one-agent types of normative positions is presented and discussed, and is put in relation to another refinement by Jones and Sergot. It is shown in the report that, based on different interpretations of the action operator Do, each of these refinements can be given an interpretation within the context of norm-regulated Dalmas (a class of transition systems regulated by conditional norms based on the theory of normative positions) and other similar systems.

  • 24.
    Ivarsson, Mikael
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Kraschrapportering för förbättrad återkoppling från användare2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta arbete undersöker hur krascher i mjukvara kan rapporteras till ett utvecklingsföretag på ett enkelt men effektivt vis. Mjukvaruföretaget Monitor i Hudiksvall utvecklar affärssystem, och som all mjukvara under utveckling finns där buggar som emellanåt kan få programmet att krascha. Vid händelse av en krasch vill företaget gärna få reda vad som gick fel så det kan lösas. Det befintliga systemet analyserades och en prototyp utvecklades. En enkätundersökning som gjordes pekade mot att flera kunder drar sig för att rapportera när programmet fallerar på grund av att det är en tidskrävande process och för flertalet känns det inte meningsfullt. Att då ge möjligheten att automatisera hela processen kan hjälpa företaget öka antalet rapporter och med tiden få en tydlig bild över var de största problemområdena ligger. Istället för att låta användaren själv skicka e-post med en rapport togs en lösning fram som skickar via HTTP. Denna teknik tillåter att rapporter enklare kan sorteras och användas för att föra statistik över de största problemområdena i programmet. I det gamla systemet öppnas ett nytt supportärende i och med varje rapport som skickas in, men den utvecklade prototypen föreslår en lösning som låter kraschinformation rapporteras med ett enkelt knapptryck eller, om så kunden önskar, öppna ett supportärende. Lösningsförslaget som presenteras i arbetet skulle på sikt kunna minska på antalet timmar som läggs ner på att manuellt analysera buggrapporter.

  • 25.
    Jansson, Elin
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Eriksson, Marie
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Metod för automatisk textplacering i digitala kartor2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Användningen av digitala kartor ökar och det medför att karttjänster måste vara flexibla och visuellt enkla att tolka. Syftet med studien är att undersöka metoder för automatisk textplacering och jämföra dem med hur andra karttjänster placerar ut sin information. Utifrån de regler och riktlinjer som finns dokumenterade från tidigare forskning har metoder för olika kartlager skapats för att placera ut text automatiskt i kartan. Resultatet av studien visar att metoden fungerar vid den begränsade datamängd som omfattade 6 kartlager. Texten placeras ut på den lämpligaste platsen för objektet texten representerar. Slutligen kan det fastställas att detta är ett område som behöver vidareutvecklas för att kunna hantera stora datamängder.

  • 26.
    Jenke, Peter
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Hast, Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    On the quality of point-cloud triangulations based on convex hulls2010In: Proceedings of the Annual SIGRAD Conference 2010, 2010, p. 71-76Conference paper (Refereed)
  • 27.
    Kjellin, Andreas
    et al.
    Uppsala University.
    Pettersson, Lars Winkler
    Uppsala university.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Lind, Mats
    Uppsala University.
    Evaluating 2D and 3D Visualizations of Spatiotemporal Information2010In: ACM Transactions on Applied Perception, ISSN 1544-3558, E-ISSN 1544-3965, Vol. 7, no 3, p. 19:1-19:23Article in journal (Refereed)
    Abstract [en]

    Time-varying geospatial data presents some specific challenges for visualization. Here, we report the results of three experiments aiming at evaluating the relative efficiency of three existing visualization techniques for a class of such data. The class chosen was that of object movement, especially the movements of vehicles in a fictitious landscape. Two different tasks were also chosen. One was to predict where three vehicles will meet in the future given a visualization of their past movement history. The second task was to estimate the order in which four vehicles arrived at a specific place. Our results reveal that previous findings had generalized human perception in these situations and that large differences in user efficiency exist for a given task between different types of visualizations depicting the same data. Furthermore, our results are in line with earlier general findings on the nature of human perception of both object shape and scene changes. Finally, the need for new taxonomies of data and tasks based on results from perception research is discussed.

  • 28.
    Lim, Nancy J.
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Brandt, S. Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Assessment of spatial-based decisions and user perspectives in utilisation of flood certainty mapsManuscript (preprint) (Other academic)
  • 29.
    Lim, Nancy Joy
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Brandt, S. Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Land management, GIS.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Division of Visual Information and Interaction, Department of Information Technology, Uppsala University, Uppsala, Sweden.
    Visualisation and evaluation of flood uncertainties based on ensemble modelling2016In: International Journal of Geographical Information Science, ISSN 1365-8816, E-ISSN 1365-8824, Vol. 30, no 2, p. 240-262Article in journal (Refereed)
    Abstract [en]

    This study evaluates how users incorporate visualisation of flood uncertainty information in decision-making. An experiment was conducted where participants were given the task to decide building locations, taking into account homeowners’ preferences as well as dilemmas imposed by flood risks at the site. Two general types of visualisations for presenting uncertainties from ensemble modelling were evaluated: (1) uncertainty maps, which used aggregated ensemble results; and (2) performance bars showing all individual simulation outputs from the ensemble. Both were supplemented with either two-dimensional (2D) or three-dimensional (3D) contextual information, to give an overview of the area.The results showed that the type of uncertainty visualisation was highly influential on users’ decisions, whereas the representation of the contextual information (2D or 3D) was not. Visualisation with performance bars was more intuitive and effective for the task performed than the uncertainty map. It clearly affected users’ decisions in avoiding certain-to-be-flooded areas. Patterns to which the distances were decided from the homeowners’ preferred positions and the uncertainties were similar, when the 2D and 3D map models were used side by side with the uncertainty map. On the other hand, contextual information affected the time to solve the task. With the 3D map, it took the participants longer time to decide the locations, compared with the other combinations using the 2D model.Designing the visualisation so as to provide more detailed information made respondents avoid dangerous decisions. This has also led to less variation in their overall responses.

  • 30.
    Lim, Nancy Joy
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Åhlén, Julia
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Urban and regional planning/GIS-institute.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Geovisualisation of uncertainty in simulated flood maps2014In: Proceedings of the International Conferences on Interfaces and Human Computer Interaction 2014, Game and Entertainment Technologies 2014 and Computer Graphics, Visualization, Computer Vision and Image Processing 2014 - Part of the Multi Conference on Computer Science and Information Systems, MCCSIS 2014 / [ed] Katherine Blashki and Yingcai Xiao, IADIS Press , 2014, p. 206-214Conference paper (Refereed)
    Abstract [en]

    The paper presents a three-dimensional (3D) geovisualisation model of uncertainties in simulated flood maps that can help communicate uncertain information in the data being used. An entropy-based measure was employed for uncertainty quantification. In developing the model, Visualisation Toolkit (VTK) was utilised. Different data derived from earlier simulation study and other maps were represented in the model. Cartographic principles were considered in the map design. A Graphical User Interface (GUI), which was developed in Tkinter, was also created to further support exploratory data analysis. The resulting model allowed visual identification of uncertain areas, as well as displaying spatial relationship between the entropy and the slope values. This geovisualisation has still to be tested to assess its effectiveness as a communication tool. However, this type of uncertainty visualisation in flood mapping is an initial step that can lead to its adoption in decision-making when presented comprehensively to its users. Thus, further improvement and development is still suggested for this kind of information presentation.

  • 31.
    Lindahl, Lars
    et al.
    Lund university.
    Odelstad, Jan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Stratification of normative systems with intermediaries2011In: Journal of Applied Logic, ISSN 1570-8683, E-ISSN 1570-8691, Vol. 9, no 2, p. 113-136Article in journal (Refereed)
    Abstract [en]

    Writing a contract with a specific content is a ground for purchase, purchase is a ground for ownership, ownership is a ground for power to dispose. Also power to dispose is a consequence of ownership, ownership is a consequence of purchase, etc. The paper presents a continuation of the authors' previous work on the algebraic representation of ground-consequence chains in normative systems. The paper analyzes different kinds of "implicative closeness" between grounds and consequences in chains of legal concepts, in particular combinations of "weakest ground". "strongest consequence" and "minimal joining". The idea of a concept's being intermediate between concepts of two different sorts is captured by the technical notion of "intervenient", defined in terms of weakest ground and strongest consequence. Lattice theory is used for studying the links between different strata and the structure of intervenient strata. We focus on (1) intervenient minimality, (2) conjunctions and disjunctions of intervenients, (3) organic wholes of intervenients, and (4) a typology of different kinds of intervenients. Also (5), we pay attention to the properties of intervenients in a network of "strata". A legal example concerning grounds and consequences of "ownership" and "trust" is used to illustrate the application of the formal theory. (C) 2011 Elsevier B.V. All rights reserved.

  • 32.
    Liu, Fei
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Detection of Façade Regions in Street View Images from Split-and-Merge of Perspective Patches2014In: Journal of Image and Graphics, ISSN ISSN 2301-3699, Vol. 2, no 1, p. 8-14Article in journal (Refereed)
    Abstract [en]

    Identification of building façades from digital images is one of the central problems in mobile augmented reality (MAR) applications in the built environment. Directly analyzing the whole image can increase the difficulty of façade identification due to the presence of image portions which are not façade. This paper presents an automatic approach to façade region detection given a single street view image as a pre-processing step to subsequent steps of façade identification. We devise a coarse façade region detection method based on the observation that façades are image regions with repetitive patterns containing a large amount of vertical and horizontal line segments. Firstly, scan lines are constructed from vanishing points and center points of image line segments. Hue profiles along these lines are then analyzed and used to decompose the image into rectilinear patches with similar repetitive patterns. Finally, patches are merged into larger coherent regions and the main building façade region is chosen based on the occurrence of horizontal and vertical line segments within each of the merged regions. A validation of our method showed that on average façade regions are detected in conformity with manually segmented images as ground truth.

  • 33.
    Liu, Fei
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Detection of Line Features in Digital Images of Building Structures2012In: Proceedings of IADIS International Conference Computer Graphics, Visualization, Computer Vision and Image Processing 2012 (CGVCVIP 2012) / [ed] Yingcai Xiao, 2012, p. 163-167Conference paper (Refereed)
    Abstract [en]

    This paper describes method for detection of short line segments in digital images. It aims at identifying buildingsin images taken from the ground view. The process starts with the image edge map and is carried out in twodifferent levels. One is to detect long line segments usually stemming from façade edges and building silhouettes.The other one identifies shorter line segments which typically represent architectural details such as windows andentrances. Selected individual connected components in both vertical and horizontal gradient component mapsare used respectively as input to the Hough transform at this level. Our first result shows that this method iscapable of recognizing lines of interest but has also included many randomly oriented lines. The next step will beto eliminate the random line segments and correlate line segments of the two levels to classify high-level features ofbuildings in an image.

  • 34.
    Liu, Fei
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Centre for Image Analysis, Uppsala University, Uppsala, Sweden.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Centre for Image Analysis, Uppsala University, Uppsala, Sweden.
    Infrared-visible image registration for augmented reality-based thermographic building diagnostics2015In: Visualization in Engineering, ISSN 2213-7459, Vol. 3, no 1, article id 16Article in journal (Refereed)
    Abstract [en]

    Background: In virtue of their capability to measure temperature, thermal infrared cameras have been widely used in building diagnostics for detecting heat loss, air leakage, water damage etc. However, the lack of visual details in thermal infrared images makes the complement of visible images a necessity. Therefore, it is often useful to register images of these two modalities for further inspection of architectures. Augmented reality (AR) technology, which supplements the real world with virtual objects, offers an ideal tool for presenting the combined results of thermal infrared and visible images. This paper addresses the problem of registering thermal infrared and visible façade images, which is essential towards developing an AR-based building diagnostics application. Methods: A novel quadrilateral feature is devised for this task, which models the shapes of commonly present façade elements, such as windows. The features result from grouping edge line segments with the help of image perspective information, namely, vanishing points. Our method adopts a forward selection algorithm to determine feature correspondences needed for estimating the transformation model. During the formation of the feature correspondence set, the correctness of selected feature correspondences at each step is verified by the quality of the resulting registration, which is based on the ratio of areas between the transformed features and the reference features. Results and conclusions: Quantitative evaluation of our method shows that registration errors are lower than errors reported in similar studies and registration performance is usable for most tasks in thermographic inspection of building façades.

  • 35.
    Liu, Fei
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Centre for Image Analysis, Uppsala University, Uppsala, Sweden.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Centre for Image Analysis, Uppsala University.
    On the precision of third person perspective augmented reality for target designation tasks2017In: Multimedia tools and applications, ISSN 1380-7501, E-ISSN 1573-7721, Vol. 76, no 14, p. 15279-15296Article in journal (Refereed)
    Abstract [en]

    The availability of powerful consumer-level smart devices and off-the-shelf software frameworks has tremendously popularized augmented reality (AR) applications. However, since the built-in cameras typically have rather limited field of view, it is usually preferable to position AR tools built upon these devices at a distance when large objects need to be tracked for augmentation. This arrangement makes it difficult or even impossible to physically interact with the augmented object. One solution is to adopt third person perspective (TPP) with which the smart device shows in real time the object to be interacted with, the AR information and the user herself, all captured by a remote camera. Through mental transformation between the user-centric coordinate space and the coordinate system of the remote camera, the user can directly interact with objects in the real world. To evaluate user performance under this cognitively demanding situation, we developed such an experimental TPP AR system and conducted experiments which required subjects to make markings on a whiteboard according to virtual marks displayed by the AR system. The same markings were also made manually with a ruler. We measured the precision of the markings as well as the time to accomplish the task. Our results show that although the AR approach was on average around half a centimeter less precise than the manual measurement, it was approximately three times as fast as the manual counterpart. Additionally, we also found that subjects could quickly adapt to the mental transformation between the two coordinate systems.

  • 36.
    Liu, Fei
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Centre for Image Analysis, Uppsala University, Uppsala, Sweden.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Centre for Image Analysis, Uppsala University, Uppsala, Sweden.
    Precision study on augmented reality-based visual guidance for facility management tasks2018In: Automation in Construction, ISSN 0926-5805, E-ISSN 1872-7891, Vol. 90, p. 79-90Article in journal (Refereed)
    Abstract [en]

    One unique capability of augmented reality (AR) is to visualize hidden objects as a virtual overlay on real occluding objects. This “X-ray vision” visualization metaphor has proved to be invaluable for operation and maintenance tasks such as locating utilities behind a wall. Locating virtual occluded objects requires users to estimate the closest projected positions of the virtual objects upon their real occluders, which is generally under the influence of a parallax effect. In this paper we studied the task of locating virtual pipes behind a real wall with “X-ray vision” and the goal is to establish relationships between task performance and spatial factors causing parallax through different forms of visual augmentation. We introduced and validated a laser-based target designation method which is generally useful for AR-based interaction with augmented objects beyond arm's reach. The main findings include that people can mentally compensate for the parallax error when extrapolating positions of virtual objects on the real surface given traditional 3D depth cues for spatial understanding. This capability is, however, unreliable especially in the presence of the increasing viewing offset between the users and the virtual objects as well as the increasing distance between the virtual objects and their occluders. Experiment results also show that positioning performance is greatly increased and unaffected by those factors if the AR support provides visual guides indicating the closest projected positions of virtual objects on the surfaces of their real occluders.

  • 37.
    Manberger, Johan
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Mogren, Alexander
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Utveckling och utvärdering av ett användargränssnitt för geovisualisering av avvikelsedata2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Swedish Transport Administration is accountable for the long-term planning and management of the Swedish road infrastructure. An important factor for the safety on our roads is the weather. By predicting the weather it is possible to reduce the risk for accidents. There are stations that measure weather conditions along the roads with the greatest risk of slipperiness and snow drift. Monitoring of these weather station is executed with a  software for quality control of data deviations. The Swedish Transport Administration wants to replace the present interface for quality control with a more user-friendly system. In this thesis, a prototype for a new interface for quality control was created. The interface was developed in accordance with aspects for useful web design and criterias produced in the preliminary study which evaluated the present interface. The new interface displays data deviations as geovisualizations. The interface was developed by using the PostgreSQL, PostGIS, Geoserver, OpenLayers and GeoExt softwares. The usability of the interface was evaluated by the target audience it is designed for. The evaluation consisted of a heuristic evaluation with user tests and questionnaires. The outcome revealed that participants' satisfaction varied. The conclusion was that the usability of the interface is acceptable but that it has potential for improvement.

  • 38. Marchetti, A
    et al.
    Hast, Anders
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Shepherd, J.
    Tesconi, M.
    Geomemories - a Spatial-Temporal Atlas of the Italian Landscape2011In: Proceedings of International Symposium on Virtual Reality, Archaeology and Cultural Heritage, 2011Conference paper (Refereed)
  • 39.
    McCartney, Robert
    et al.
    Computer Science and Engineering Department, University of Connecticut,, Storrs, CT, United States .
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Eckerdal, Anna
    Information Technology, Department of Scientific Computing, Uppsala University, Uppsala, Sweden .
    Sanders, Kate
    Mathematics and Computer Science, Rhode Island College, Providence, RI, United States .
    Thomas, Lynda
    Department of Computer Science, Aberystwyth University, Aberystwyth, United Kingdom .
    Zander, Carol
    Computing and Software Systems, University of Washington Bothell, Bothell, WA, United States .
    Why computing students learn on their own: motivation for self-directed learning of computing2016In: ACM Transactions on Computing Education, ISSN 1946-6226, E-ISSN 1946-6226, Vol. 16, no 1, p. 2:1-2:18, article id 2Article in journal (Refereed)
    Abstract [en]

    In this article, we address the question of why computing students choose to learn computing topics on their own. A better understanding of why some students choose to learn on their own may help us to motivate other students to develop this important skill. In addition, it may help in curriculum design; if we need to leave some topics out of our expanding curriculum, a good choice might be those topics that students readily learn on their own.

    Based on a thematic analysis of 17 semistructured interviews, we found that computing students’ motivations for self-directed learning fall into four general themes: projects, social and peer interactions, joy of learning, and fear. Under these, we describe several more specific subthemes, illustrated in the words of the students.

    The project-related and social motivations are quite prominent. Although these motivations appear in theliterature, they received greater emphasis from our interviewees. Perhaps most characteristic of computingis the motivation to learn to complete some project, both projects done for fun and projects required for schoolor work.

  • 40.
    McCartney, Robert
    et al.
    Department of Computer Science and Engineering University of Connecticut Storrs, USA.
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Eckerdal, Anna
    Department of Information Technology Uppsala University Uppsala.
    Sanders, Kate
    Mathematics and Computer Science Department Rhode Island College Providence, USA.
    Zander, Carol
    Computing & Software Systems University of Washington Bothell Bothell, USA.
    Can first–year students program yet?: a study revisited2013In: ICER´13: Proceedings of the ninth International Conference on International Computing Education Research / [ed] Beth Simon, Alison Clear, Quintin Cutts, Association for Computing Machinery (ACM), 2013, p. 91-98Conference paper (Refereed)
    Abstract [en]

    Threshold concepts can be used to both organize disciplinaryknowledge and explain why students have diculties at cer-tain points in the curriculum. Threshold concepts transforma student's view of the discipline; before being learned, theycan block a student's progress.In this paper, we propose that in computing, skills, inaddition to concepts, can sometimes be thresholds. Somestudents report nding skills more dicult than concepts.We discuss some computing skills that may be thresholdsand compare threshold skills and threshold concepts.

  • 41.
    McCartney, Robert
    et al.
    Computer Science and Engineering, University of Connecticut, Storrs, CT, United States.
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Department of Information Technology, Uppsala University, Uppsala, Sweden.
    Eckerdal, Anna
    Department of Information Technology, Uppsala University, Uppsala, Sweden.
    Sanders, Kate
    Mathematics and Computer Science, Rhode Island College, Providence, RI, United States.
    Zander, Carol
    Computing and Software Systems, University of Washington Bothell, Bothell, WA, United States.
    Folk pedagogy and the geek gene: geekiness quotient2017In: Proceedings of the 2017 ACM SIGCSE Technical Symposium on Computer Science Education, NY, USA: ACM Digital Library, 2017, p. 405-410Conference paper (Refereed)
    Abstract [en]

    In a survey of the CS-education community, we find a range of beliefs about the "geek gene" theory. We suggest an alternative term, the "geekiness quotient (GQ)". The GQ, grounded in Gardner's work on multiple intelligences, is a hypothetical measure of the student's current CS ability. The GQ supports a moderate view of the geek gene: that students arrive in our classrooms with a range of CS abilities, whether acquired through background or innate talent, and can improve their abilities through effort.

  • 42.
    Milutinovic, Goran
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Ahonen-Jonnarth, Ulla
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Decision, Risk and Policy Analysis.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science. Department of Information Technology, Uppsala University, Uppsala, Sweden.
    GISwaps: A New Method for Decision Making in Continuous Choice Models Based on Even Swaps2018In: International Journal of Decision Support System Technology, ISSN 1941-6296, E-ISSN 1941-630X, Vol. 10, no 3, p. 57-78Article in journal (Refereed)
    Abstract [en]

    This article describes how continuous GIS-MCDM problems are commonly managed by combining some weighting method based on pairwise comparisons of criteria with an aggregation method. The reliability of this approach may be questioned, though. First, assigning weights to criteria, without taking into consideration the actual consequences or values of the alternatives, is in itself controversial. Second, the value functions obtained by this approach are in most cases linear, which is seldom the case in reality. The authors present a new method for GIS-MCDM in continuous choice models based on Even Swaps. The method is intuitive and easy to use, based on value trade-offs, and thus not relying on criteria weighting. Value functions obtained when using the method may be linear or non-linear, and thereby are more sensitive to the characteristics of the decision space. The performed case study showed promising results regarding the reliability of the method in GIS-MCDM context.

  • 43.
    Milutinovic, Goran
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Visual GISwaps - an interactive visualization framework for geospatial decision making2018In: Proceedings of the 13th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications, VISIGRAPP 2018, Funchal, Madeira - Portugal, January 27-29, 2018 / [ed] Alexandru Telea, Andreas Kerren and Jose Braz, SciTePress, 2018, p. 236-243Conference paper (Refereed)
    Abstract [en]

    Different visualization techniques are frequently used in geospatial information systems (GIS) to support geospatial decision making. However, visualization in GIS context is usually limited to the initial phase of the decision-making process, i.e. situation analysis and problem recognition. This is partly due to the choice of methods used in GIS multi-criteria decision-making (GIS-MCDM) that usually deploy some non-interactive approach, leaving the decision maker little or no control over the calculation of overall values for the considered alternatives; the role of visualization is thus reduced to presenting the final results of the computations. The contributions of this paper are twofold. First, we introduce GISwaps, a novel, intuitive interactive method for decision making in geospatial context. The second and main contribution is an interactive visualization of the choice phase of the decision making process. The visualization allows the decision maker to explore the consequences of trade-offs and costs accepted during the iterative decision process, both in terms of the abstract relation between different decision variables and in spatial context.

  • 44. Nyström, Ingela
    et al.
    Olsson, Pontus
    Nysjö, Johan
    Nysjö, Fredrik
    Malmberg, Filip
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Hirsch, Jan-Michel
    Carlbom, Ingrid B.
    Virtual Cranio-Maxillofacial Surgery Planning with Stereo Graphics and Haptics2016In: Computer-Assisted Musculoskeletal Surgery: Thinking and Executing in 3D / [ed] Ritacco, L .E. and Milano, F. E. and Chao, E., Springer Publishing Company, 2016, 1, p. 29-42Chapter in book (Refereed)
  • 45.
    Olsson, Christian
    et al.
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Suau Carvajal, Nicolas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Utveckling av applikation för visualisering av data kring kulturverksamhet – med fokus på användbarhet: En studie för Region Gävleborg2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport behandlar ämnet användbarhet och hur det kan tillämpas på Region Gävleborgs avdelning Kulturutveckling. Idag saknar de en applikation som tillhandahåller tjänsten att med hjälp av Excel-data grafiskt på en karta visualisera kulturaktörer med regionalt uppdrag och deras verksamhet.

    För att kunna skapa och utforma en användarvänlig applikation har författarna undersökt olika tillämpningar, definitioner och standarder som rör användbarhet. Ett användartest utfördes för att bekräfta författarnas tes om att med hjälp av Shneidermans gyllene regler tillverka en applikation som i framtiden kan användas för att underlätta beslutsfattande kring de kulturella aktörernas verksamhet i regionen.

    Författarna har utöver feedbacken från de tilltänkta användarna även tagit fram en lathund för att möjliggöra användare med olika kunskap och erfarenhet att använda applikationen som redskap i deras arbete. Slutsatsen som kan dras är att det är tillräckligt att tillämpa en uppsättning användbarhetsregler för att skapa en användarvänlig applikation.

  • 46.
    Olsson, Pontus
    et al.
    Uppsala universitet, Informationsteknologi.
    Nysjö, Fredrik
    Uppsala universitet, Informationsteknologi.
    Seipel, Stefan
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Carlbom, Ingrid
    Uppsala universitet, Informationsteknologi.
    Physically Co-Located Haptic Interaction with 3D Displays2012In: Proc. Haptics Symposium (HAPTICS), 2012 IEEE, 2012, p. 267-272Conference paper (Refereed)
    Abstract [en]

    Studies indicate that haptic interaction with a computer generated virtual scene may become more intuitive by aligning (co-locating) the visual and haptic workspaces so that the visual and haptic feedback coincide as they do in the real world. Co-located haptics may gain importance when more advanced haptic interfaces, such as high-fidelity whole hand devices, become available. We describe a user study that investigates the pros and cons with physically co-located versus non-collocated haptics on two different display types: a commercial half-transparent mirror 3D display with shutter glasses and a prototype autostereoscopic display based on a Holographic Optical Element (HOE). We use two accuracy tasks with spatial accuracy as the dependent variable and one manipulation task with time as the dependent variable. The study shows that on both displays co-location significantly improves completion time in the manipulation task. However, the study shows that co-location does not improve the accuracy in the spatial accuracy tasks.

  • 47.
    Pettersson, David
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Utveckling av ett krypterat meddelandesystem2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today there exists many messaging applications and new ones are released almost daily. However, there are not as many messaging applications where both the client application and the server application are open source and can be self hosted. These messaging applications are good at solving the problem that many, up to several million people can communicate with each other. However, there is a smaller more focused use case with a messaging system consisting of only one message flow, where all messages are visible to all devices. This smaller use case means that less metadata is required. Uses for such a messaging system may be to receive notifications from servers or to take personal notes. The message system is synchronized between all devices. The goal of this project is to create an End-to-End encrypted messaging system that provides authentication, data integrity and confidentiality. Research has been investigated regarding weaknesses in some encryption techniques, these weaknesses have been taken into account when creating the messaging system. The purpose why this messaging system needs to be created is because an existing system that meets certain essential requirements for maintaining maximum personal integrity is missing. A prototype has been created that consists of a server application and a graphical computer application. Messages sent in the messaging system are End-to-End encrypted. Communication between clients and the server is also encrypted and authenticated.

  • 48.
    Rasmussen, Daniel
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Utveckling av en karttjänst och utvärdering av användbarhet: Realtidsrapportering om aktuell position för vägbommar2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna studie har undersökt vilka användbarhetsfaktorer och funktioner som gör att en karttjänst får hög användbarhet och ökad tillgänglighet till allmänheten. En karttjänst utvecklades som utgångspunkt i studien. Karttjänsten kan lagra aktuella positionsdata för vägbommar. Karttjänsten användes i samband med användbarhetstester för att evaluera användbarheten. Resultaten från användbarhetsundersökningen avhandlar användbarhetsfaktorer i användargränssnittet. Crowdsourcing antogs som förutsättning och användes som underlag i utformningen av användbarhetsundersökningen.

  • 49. Sanders, Kate
    et al.
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Eckerdal, Anna
    McCartney, Robert
    Moström, Jan Erik
    Thomas, Lynda
    Zander, Carol
    Threshold concepts and threshold skills in computing2012In: Proceedings of the ninth annual international conference on International computing education research, New York, NY, USA: Association for Computing Machinery (ACM), 2012, p. 23-30Conference paper (Refereed)
    Abstract [en]

    Threshold concepts can be used to both organize disciplinary knowledge and explain why students have difficulties at certain points in the curriculum. Threshold concepts transform a student's view of the discipline; before being learned, they can block a student's progress.

    In this paper, we propose that in computing, skills, in addition to concepts, can sometimes be thresholds. Some students report finding skills more difficult than concepts. We discuss some computing skills that may be thresholds and compare threshold skills and threshold concepts.

  • 50.
    Sanders, Kate
    et al.
    Rhode Island College, Providence, Rhode Island, USA.
    Boustedt, Jonas
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management, Computer science.
    Eckerdal, Anna
    Uppsala University, Uppsala, Sweden.
    McCartney, Robert
    University of Connecticut, Storrs, Connecticut, USA.
    Zander, Carol
    University of Washington, Bothell Bothell, Washington, USA.
    Folk Pedagogy: Nobody Doesn't Like Active Learning2017In: Proceedings of the 2017 ACM Conference on International Computing Education Research (ICER 17) / [ed] Josh Tenenberg and Lauri Malmi, Tacoma, Washington, USA: ACM Publications, 2017, p. 145-154Conference paper (Refereed)
    Abstract [en]

    In a survey of the computing education community, many respondents suggested "active learning" as a teaching approach that would increase the likelihood of student success. In light of these responses, we analyze the way in which active learning is described in the computing-education literature. We find a strong consensus that active learning is good, but a lack of precision in how the term is used, often without definition, to describe instructional techniques, rather than student learning. In addition, active learning techniques are often discussed as if they were all equally effective. We suggest that making clear distinctions, both between teaching techniques and active learning and among the teaching techniques, would be fruitful for both instructors and researchers. Finally, we propose some dimensions along which distinctions among techniques could usefully be made.

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