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  • 101.
    Jonsson, Torsten
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Visual Basic i Fokus: grundläggande applikationsutveckling och programmering version 62003 (ed. 3)Book (Other academic)
  • 102.
    Jonsson, Torsten
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Hamfelt, Andreas
    DAViLa – A Domain Adaptable Visual Language2003In: Human Centric Computing Languages and Environments, 2003Conference paper (Other academic)
    Abstract [en]

    We present a framework where different visual notations may be implemented to suit different domains. The major characteristic of DAViLa is that it provides a domain in-dependent framework to programming, using components of interest for specific domains. A domain adaptation is achieved through implementation of domain specific components, which are added to the framework. The semantics of the framework is based on Combilog, a com-positional programming method for relational programs. In Combilog, programming semantically is composition of sets of tuples

  • 103. Kabilan, Vandana
    et al.
    Zdravkovic, Jelena
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Johannesson, Paul
    Using Multi Tier Contract Ontology to Deduce Contract Workflow Models for Enterprise Process Interoperability2005In: Proceedings of the INTEROP EMOI Workshop. CAiSE’05 Workshop, 2005Conference paper (Other academic)
    Abstract [en]

    Ontologies are being proposed as a medium for affecting enterprise application integration. Though it is widely accepted that ontologies can support inter- enterprise interoperability, the exact nature and extent to which ontology may be useful is uncertain. We promote the use of ontology in a two-fold way: first, as a knowledge base for fostering human-to-human shared understanding; second, as an ‘interlingua’ for promoting human-to-machine specification as well as semantics-to-execution. The proposed concept is described using a case scenario in the realm of legal business contracts, followed by their integration to the business domain, with an objective to model contract compliant business process models. With the case, we illustrate the use of Multi-Tier Contract Ontology (MTCO) to deduce a high level, partial business process model named the Contract Workflow Model (CWM). Such a model, from the business process perspective, may be used as a skeleton for designing internal business processes for each individual contracting party, or for mapping to existing processes.

  • 104. Kordaß, B.
    et al.
    Gärtner, Ch.
    Söhnel, A.
    Bisler, A.
    Voß, G.
    Bockholt, U.
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    The virtual articulator in dentistry: concept and development2002In: Dental Clinics of North America, ISSN 1558-0512, Vol. 46, no 3, p. 493-506Article in journal (Refereed)
    Abstract [en]

    Virtual Reality (VR) technology is one of the most important innovations for research, development, and industrial production. In dentistry, VR technology will be useful in providing better education through simulation and in enhancing working procedures that are conventionally limited, e.g., the mechanical articulator. It is the purpose of this article to present concepts and strategies for a future replacement of the mechanical articulator by a virtual one.

  • 105. Kuikka, K
    et al.
    Härmä, E
    Markkola, A M
    Rauti, P
    Roitto, M
    Saikkonen, K
    Ahonen-Jonnarth, Ulla
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Finlay, R
    Tuomi, J
    Severe defoliation of Scots pine reduces reproductive investment by ectomycorrhizal symbionts2003In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 84, no 8, p. 2051-2061Article in journal (Refereed)
    Abstract [en]

    Reduction in the photosynthetic capacity of plants is presumed to negatively affect their fungal symbionts. To test this hypothesis under natural conditions, we artificially removed 100% of previous year needles in two successive years on Scots pine trees (Pinus sylvestris L.) to simulate pine sawfly attack. Despite a decline in the shoot growth of defoliated trees, root biomass did not differ from control trees. The ergosterol (fungal biomass) and starch concentration of fine roots, however, slightly declined in defoliated trees. Percent ectomycorrhizal colonization of fine root tips remained high in both defoliated and control trees. The dominant tubercle morphotypes were slightly more abundant in the control than in defoliated trees. In contrast to the relatively weak effects on vegetative ectomycorrhizae, reproduction declined near the defoliated pines. Average sporocarp numbers and, consequently, the relative fungal investment to reproduction of the estimated total fungal biomass were more than three times higher near controls than defoliated trees in the first treatment year. Defoliation also reduced the diversity of ectomycorrhizal species producing sporocarps. Mutualistic fungal symbionts may thus alter their reproductive investment in response to restrictions on host resources. Because fungal biomass in the roots as well as colonization percentage remained unchanged, Scots pine evidently continues to invest in the maintenance of the symbiosis despite the reduced photosynthetic capacity due to defoliation.

  • 106. Larsson, P
    et al.
    Lehnbom, J
    Ahonen-Jonnarth, Ulla
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Beståndssimulering. Delrapport inom projektet Skogssimulering: Beskrivning av programmet Beståndssimulator 1.02004Report (Other academic)
  • 107.
    Larsson, Robin
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Anbudskalkylering: utveckling av ett Java EE-baserat system2009Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Ett konsultföretag får in anbudsförfrågningar och måste därmed göra kalkyler för dessa förfrågningar. Med hjälp av ett webbaserat system där en anställd kan göra kalkyleringar kan företaget få ett gemensamt sätt att arbeta och uppföljningen underlättas. Systemet som har skapats ger användare möjlighet att göra anbudskalkyler genom en överskådlig och lättarbetad webbsida, där man kan se förhållandet mellan företagets kostnad gentemot kundpriset. All information lagras persistent i en databas för att möjliggöra uppföljning och synkronisering med andra system som används på företaget.

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  • 108.
    Leffler, Otto
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Automatic Character Rigging in Maya2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Detta arbete kommer att handla om att skapa ett system för att automatiseraprocessen att skapa en karaktärsrig i programmet Maya. Med hjälp av programmets inbyggda programmeringsspråk MEL kommer systemet, via ett grafiskt gränssnitt, skapa just det resultat som användaren efterfrågar.Resultatet är ett verktyg som kan skapa en komplett karaktärsrig på under 3 minuters tid! Ett arbete som annars kan ta flera dagar.

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  • 109. Lind, M.
    et al.
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Mattiason, C.
    Displaying meta-information in context2001In: Behavior and Information Technology, ISSN 0144-929X, E-ISSN 1362-3001, Vol. 20, no 6, p. 427-432Article in journal (Refereed)
    Abstract [en]

    Very often information exists that would be helpful for process control operators if it could be presented in the context they work in-the process graphics. Examples are instructional material, visualizations of automated sequences, output from knowledge-based systems or simply annotations that one team of operators wants to communicate with another. Several existing distortion techniques were reviewed that would allow the ordinary process graphics to take less space leaving room for additional information. However, these techniques were rejected, mainly because all parts of a process control screen need to be readable at all times. A new technique is proposed and its readability experimentally evaluated with promising results.

  • 110. Lindahl, L
    et al.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Intermediate Concepts in Normative Systems2006In: DEON 2006, LNAI 4048 / [ed] Lou Goble, John-Jules Ch. Meyer, Berlin: Springer , 2006, p. 187-200Conference paper (Other academic)
    Abstract [en]

    In legal theory, a well-known idea is that an intermediate concept like "ownership" joins a set of legal consequences to a set of legal grounds. In our paper we attempt to make the idea of a joining between grounds and consequences more precise by using an algebraic representation of normative systems earlier developed by the authors. In the first main part the idea of intermediate concepts is presented and earlier discussions of the subjects are outlined. Subsequently, in the second main part, we introduce a more rigorous framework and develop the formal theory. In the third part the formal framework is applied to examples and some remarks on a methodology of intermediate concepts are given.

  • 111. Lindahl, L.
    et al.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Normative Systems and Their Revision: An Algebraic Approach2004In: Artificial Intelligence and Law, ISSN 0924-8463, E-ISSN 1572-8382, Vol. 11, no 2-3, p. 81-10Article in journal (Refereed)
    Abstract [en]

    The paper discusses normative systems and their revision within an algebraic framework. If a system is logically well-formed, certain norms, called connecting norms, determine the system as a whole. It is maintained that, if the system is well-formed, a relation "at least as low as" determines a lattice or quasi-lattice of its connecting norms. The ideas are presented mainly in the form of comments on a legal example concerning acquisition of movable property by extinction of another person's previous rights.

  • 112.
    Lindahl, Lars
    et al.
    Faculty of Law, University of Lund, Sweden.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap. DSV, KTH, Sweden.
    Intermediaries and intervenients in normative systems2008In: Journal of Applied Logic, ISSN 1570-8683, E-ISSN 1570-8691, Vol. 6, no 2, p. 229-250Article in journal (Refereed)
    Abstract [en]

    Many concepts in legal texts are "intermediaries", in the sense that they serve as links between statements of legal grounds, on one hand, and of legal consequences, on the other. In our paper, an algebraic representation of normative systems is used for distinguishing between different kinds of intermediaries and making the idea of a joining between grounds and consequences more precise. In Section 1, the idea of intermediaries is presented and earlier discussions of the subjects are outlined. In Section 2, we introduce the algebraic framework and develop the formal theory. After introducing our approach to the representation of a normative system, we here present a theory of "intervenients", seen as a tool for analysing intermediaries. In Section 3, dealing with applications, after presenting a model of the formal theory, suited for the analysis of concepts in normative systems, we apply the theory to a number of examples, introduced in the first part. Finally, in Section 4, we make some remarks on the methodology of intermediate concepts.

  • 113. Lindahl, Lars
    et al.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Open and closed intermediaries in normative systems2006In: Legal knowledge and information systems: JURIX 2006: the Nineteenth Annual Conference / [ed] Tom M. van Engers, Amsterdam: IOS Press , 2006, p. 91-99Conference paper (Other academic)
  • 114. Lindahl, Lars
    et al.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Strata of intervenient concepts in normative systems2008In: Deontic Logic in Computer Science: 9 th International Conference, DEON 2008, Luxembourg, Luxembourg, July 15-18, 2008. Proceedings, Berlin, Heidelberg: Springer , 2008, p. 203-217Conference paper (Refereed)
  • 115.
    Lundgren, Mattias
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Analys av applikationsservrar med avseende på Lantmäteriets behov2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En applikationsserver agerar i regel som en förmedlande server i ett tre-skikt-system med en webbserver på ena sidan och en databasserver på andra sidan. De används för att komma åt funktioner i en databas med hjälp av program skrivna för just den applikationsserver som används. På Lantmäteriets huvudkontor i Gävle använder man sig i dagsläget av 5 stycken olika applikationsservrar, vilket medför stora kostnader i bland annat licenser, support och kompetensutveckling. I detta arbete undersöks skillnader i pris och funktionalitet mellan de aktuella applikationsservrarna samt hur man på bästa sätt kan minska kostnaderna för Lantmäteriet genom att sätta upp ett mål där applikationsservrarna används på ett effektivare sätt. För att ta reda på detta har jag intervjuat personer inom Lantmäteriet angående det nuvarande problemet och tagit reda på hur man kan göra för att möjliggöra en utfasning av en eller flera applikationsservrar. Det framtagna resultatet visar att det är bäst att använda så få applikationsservrar som möjligt, gärna endast en enda ur kostnadssynpunkt. För att göra det möjligt bör man i fortsättningen endast utveckla program för Red Hats applikationsserver JBoss samt försöka migrera befintliga applikationer till den plattformen.

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  • 116.
    Markkola, A. M
    et al.
    University of Oulu, Finland.
    Ahonen-Jonnarth, Ulla
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Roitto, M.
    University of Oulu, Finland.
    Strömmer, R.
    University of Helsinki.
    Hyvärinen, M.
    University of Oulu, Finland.
    Shift in ectomycorrhizal community composition in Scots pine (Pinus sylvestris L.) seedling roots as a response to nickel deposition and removal of lichen cover2002In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 120, no 3, p. 797-803Article in journal (Refereed)
    Abstract [en]

    Scots pine seedlings were exposed to wet-deposited nickel (Ni) and removal of lichen cover in a dry heath Scots pine forest. Ni deposition affected the colonization of roots by indigenous ectomycorrhizal fungi in contrasting ways in intact and skimmed quadrats. Highest frequencies of tubercle morphotypes of ectomycorrhiza were found in quadrats exposed to 100 mg m-2 year-1 Ni in lichen covered treatment, while in skimmed quadrats these peaked after the treatment with 10 mg Ni m-2 year-1. Removal of the lichen layer increased the value of diversity index (H′) of ectomycorrhizal fungal community, probably due to the increase in the evenness of the morphotype distribution. Lichen removal seemed also to improve the condition of the short roots, as the frequencies of poor and senescent short roots were decreased by the removal.

  • 117. Markkola, A M
    et al.
    Ohtonen, A
    Ahonen-Jonnarth, Ulla
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Ohtonen, R
    Scots pine responses to CO2 enrichment--I. Ectomycorrhizal fungi and soil fauna.1996In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 94, no 3, p. 309-16Article in journal (Refereed)
    Abstract [en]

    Ectomycorrhizal Scots pine seedlings were grown in unfertilized forest soil at ambient and double (ca 700 ppm) atmospheric concentrations of CO2. The biomass of seedlings and fungal biomass both in the roots and in the soil and the numbers of certain groups of soil animals were measured under summer conditions and after an artificial winter acclimation period. No biomass parameter showed any significant change due to CO2 elevation. Increases were found during the winter acclimation period in total and fine root biomasses, fungal biomass in the soil and total fungal biomass both in the roots and in the soil, while the ratio of needle biomass: fungal biomass and the shoot: root ratio decreased. The N concentration in previous-year needles was lower in the double CO2 environment than with ambient CO2. Enchytraeids almost disappeared in the double CO2 environment during winter acclimation, while the numbers of nematodes increased at the same time in both treatments.

  • 118. Markkola, A. M
    et al.
    Tarvainen, O.
    Ahonen-Jonnarth, Ulla
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Strömmer, R. R
    Urban polluted forest soils induce elevated root peroxidase activity in Scots pine (Pinus sylvestris L.) seedlings2002In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 116, no 2, p. 273-278Article in journal (Refereed)
    Abstract [en]

    Plant biomass, mycorrhizal status and root peroxidase activity were measured in ectomycorrhizal Scots pine (Pinus sylvestris L.) seedlings grown in urban polluted and native, non-polluted forest soils with added ammonium or potassium sulphates simulating N and S deposition of urban areas. Peroxidase activity in the fine roots of seedlings planted in polluted forest soils was higher than in those planted in non-polluted soils and correlated positively with the activities measured in an earlier study in the roots of mature Scots pines growing at the sites from where the soils were collected. Growth of seedlings and mycorrhizal status were not affected by the origin of soil. Exposing the seedlings to winter acclimation conditions for 6 weeks elevated peroxidase activity in the roots. The addition of ammonium or potassium sulphate to non-polluted soils did not induce elevated root peroxidase activity, although at the levels of 0.5 and 1.0 g of ammonium sulphate a slight increasing trend was observed. We suggest, that indirect biotic factors, i.e. changes in the community structure of soil fungi, early stages of recognition, and defence reactions of pine roots against saprophytic and pathogenic fungi may be participating in the elicitation of peroxidase (POD) activity, although the possible role of heavy metals cannot be excluded.

  • 119. Markkola, A.M.
    et al.
    Ohtonen, R.
    Tarvainen, O.
    Ahonen-Jonnarth, Ulla
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Estimates of fungal biomass in Scots pine stands on an urban pollution gradient1995In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 131, no 1, p. 139-147Article in journal (Refereed)
    Abstract [en]

    Biomasses of ectomycorrhizal and saprotrophic fungal communities partitioned into sporophores and non‐reproductive structures were estimated in mature Scots pine (Pinus sylvestris L.) stands along an urban nitrogen and sulphur pollution gradient in northern Finland. The average total biomass of fungi varied in the four pollution zones from 14.6 to 20.2 g d. Wt kg−1 soil d. wt and from 73.3 to 108.0 g d. Wt m−2, the mycelia of both mycorrhizai and saprotrophic fungi in the soil comprising 72–80% of the total. The annual carbon allocation to the fungal communities was calculated to vary between 9 and 26% of the estimated annual carbon assimilation at the Scots pine sites. The size of the mean fungal biomass fractions decreased in the following sequence: mycelia in the soil > fungal biomass in fine roots estimated in terms of chitin > sclerotia > fungal biomass in fine roots estimated in terms of ergosterol > sporopbores of mycorrhizal fungi > sporophores of saprotrophie fungi. A positive correlation was obtained between the number of Scots pine mycorrhiza and the average sporophore yield of mvcorrhiaal fungi for three successive years. Tbe sporophore biomass of the mycorrhizal fungi was smaller at the most polluted than at the least polluted sites. The total fungal biomass allocation was not affected by urban pollution. 

  • 120. McCartney, Robert
    et al.
    Boustedt, Jonas
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Eckerdal, Anna
    Moström, Jan-Erik
    Sanders, Kate
    Thomas, Lynda
    Zander, Carol
    Liminal Spaces and Learning Computing2009In: European Journal of Engineering Education, ISSN 0304-3797, E-ISSN 1469-5898, Vol. 34, no 4, p. 383-391Article in journal (Refereed)
    Abstract [en]

    “Threshold concepts” are concepts that, among other things, transform the way a student looks at a discipline. Although the term “threshold” might suggest that the transformation occurs at a specific point in time, an “aha” moment, it seems more common (at least in computing) that a longer time period is required. This time period is referred to as the “liminal space.”

    In this paper, we summarise our findings concerning how computing students experience the liminal space and discuss how this might affect teaching. Most of our findings so far relate to software engineering. As similar liminal spaces likely occur in other engineering disciplines, these findings have relevance across engineering education.

  • 121.
    Mohammadi, S.M
    et al.
    Uppsala universitet.
    Hast, Anders
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Daldorff, L.K.S
    Uppsala universitet.
    Ericsson, M
    Uppsala universitet.
    Bergman, J.E.S
    Uppsala universitet.
    Thidè, Bo
    Uppsala universitet.
    Interactive visualization of new electromagnetic quantities2008In: SIGRAD 2008: The Annual SIGRAD Conference Special Theme: Interaction, Linköping University Electronic press , 2008, p. 71-74Conference paper (Refereed)
  • 122. Moström, Jan Erik
    et al.
    Boustedt, Jonas
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Eckerdal, Anna
    McCartney, Robert
    Sanders, Kate
    Thomas, Lynda
    Zander, Carol
    Concrete examples of abstraction as manifested in students’ transformative experiences2008In: ICER '08: proceedings of the fourth international workshop on Computing education research, New York: ACM , 2008, p. 125-136Conference paper (Refereed)
    Abstract [en]

    This paper examines transformational learning experiences of computing students as a way to better understand threshold concepts in computing. From empirical evidence we found that students often describe transformative experiences as learning situations in which they were led to use various kinds of abstraction, for example modularity, data abstraction, inheritance, polymorphism, reuse, design patterns, and complexity. Some students describe an abstract concept as coming first, and then needing to be made concrete though application; others describe transformations in which they learn the advantages of these abstract concepts from their experience of not using them.

    Abstraction is certainly of central importance in computer science. It appears, however, from our students’ descriptions of transformative experiences, that abstraction per se is not a threshold, but that particular concepts in which abstraction is paramount exhibit the characteristics of threshold concepts.

  • 123. Moström, Jan-Erik
    et al.
    Boustedt, Jonas
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Eckerdal, Anna
    McCartney, Robert
    Sanders, Kate
    Thomas, Lynda
    Zander, Carol
    Computer Science Student Transformations: Changes and Causes2009In: ITiCSE'09: Proceedings of the 14th ACM–SIGCSE Annual Conference on Innovation and Technology in Computer Science Education, New York: ACM , 2009, p. 181-185Conference paper (Refereed)
    Abstract [en]

    We examine the transformations experienced by students during their study of computing. These transformations led to changes in the students’ perception of computing and in their behavior, confidence, and sense of identity as computing professionals. We discuss these transformations, their causes, and implications for the learning and teaching of computer science.

  • 124.
    Norén, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Postapokalyptisk postproduktion2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Det här projektet går ut på att skapa en effekt så att det ser ut som en olycka har varit framme på ett inspelat material. Syftet är att i första hand försöka skapa en liknande filmsekvens som i en redan producerad film men också att få förståelse för post produktions programmet Fusion. De tekniker som användes för att ändra det filmade materialet var att föra in bilder och skapa 3D-objekt och sedan använda 2D och 3D-tracking för att få de att sitta på plats. Resultatet blev en kort film som når upp till ursprungsmålen men som egentligen skulle behövt mycket mer tid för att bli riktigt bra.

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  • 125.
    Nyh, Andréas
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Lindroth, Johanna
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Visualisering i 3D av Öjebergets framtidsvision2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna uppsats visar utvecklingen av ett konferenshotell i 3D med restaurang, spa och omkringliggande stugor samt modellerad omgivning. Vi fick uppgiften att modellera Öjeberget Järvsö AB: s vision om hur deras ombygge av skidorten Öjeberget ska se ut. Vi använde oss av programmet Autodesk Maya 2009 att göra modellerna och Adobe Premiere för att redigera våra kameraåkningar. Anledningen till att kunden ville ha deras ännu ej genomförda ombyggnad i 3D var för att visa sponsorer och eventuella framtida gäster hur ombyggnaden skulle kunna se ut och hur arbetet fortlöper.

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  • 126.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Agents, norms and forest cleaning2007In: Normative multi-agent systems: Dagstuhl seminar 07122, 18.03. - 23.03.2007, 2007, p. 15-Conference paper (Refereed)
    Abstract [en]

    The automation of forest cleaning presupposes principles for choosing those trees that ought to be taken away and those that shall be left standing. In this paper, which is a report on a work in progress, the question is raised whether those principles can be structured as a combination of a normative system and a utility function. Of special interest is the possibility that the agent system can evaluate the efficiency of the normative system and the utility function and, furthermore, suggest improvements of them. Earlier works on norms and norm-regulation of agent systems that the author has been involved in are used to elucidate the problem area discussed in the paper.

  • 127.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    An Abstract Architecture for Norm-Regulated Agents2003In: Promote IT 2003, 2003Conference paper (Other academic)
  • 128.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    An essay on msic-systems2009In: Normative Multi-Agent Systems / [ed] Guido Boella and Pablo Noriega and Gabriella Pigozzi and Harko Verhagen, Dagstuhl, Germany: Schloss Dagstuhl - Leibniz-Zentrum für Informatik , 2009Conference paper (Refereed)
    Abstract [en]

    A theory of many-sorted implicative conceptual systems (abbreviated msic-systems) is outlined. Examples of msic-systems include legal systems, normative systems, systems of rules and instructions, and systems expressing policies and various kinds of scientific theories. In computer science, msic-systems can be used in, for instance, legal information systems, decision support systems, and multi-agent systems. In this essay, msic-systems are approached from a logical and algebraic perspective aiming at clarifying their structure and developing effective methods for representing them. Of special interest are the most narrow links or joinings between different strata in a system, that is between subsystems of different sorts of concepts, and the intermediate concepts intervening between such strata. Special emphasis is put on normative systems, and the role that intermediate concepts play in such systems, with an eye on knowledge representation issues. In this essay, normative concepts are constructed out of descriptive concepts using operators based on the Kanger-Lindahl theory of normative positions. An abstract architecture for a norm-regulated multi-agent system is suggested, containing a scheme for how normative positions will restrict the set of actions that the agents are permitted to choose from.

  • 129.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Intresseavvägning. En beslutsfilosofisk analys med tillämpning på planering2002Book (Other academic)
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  • 130.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Many-Sorted Implicative Conceptual Systems2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A theory of many-sorted implicative conceptual systems (abbreviated msic-systems) is presented. Examples of msic-systems include legal systems, normative systems, systems of rules and instructions, and systems expressing policies and various kinds of scientific theories. In computer science, msic-systems can be used in, for instance, legal information systems, decision support systems, and multi-agent systems. In the thesis, msic-systems are studied from a logical and algebraic perspective aiming at clarifying their structure and developing effective methods for representing them. Of special interest are the most narrow links or joinings between different strata in a system, that is between subsystems of different sorts of concepts, and the intermediate concepts intervening between such strata. Special emphasis is put on normative systems, and the role that intermediate concepts play in such systems, with an eye on knowledge representation issues. Normative concepts are constructed out of descriptive concepts using operators based on the Kanger-Lindahl theory of normative positions. An abstract architecture for a norm-regulated multi-agent system is suggested, containing a scheme for how normative positions will restrict the set of actions that the agents are permitted to choose from. Technical results inlude a characterization of an msic-system in terms of the most narrow joinings between different strata, characterization of the structure of the most narrow joinings between two strata, conditions for the extendability of intermediate concepts, and finally, a specification of the conditions such that the Boolean operations on intermediate concepts will result in intermediate concepts and characterization of most narrow joinings in terms of weakest grounds and strongest consequences.

  • 131.
    Odelstad, Jan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Norms for Multi-Agent Systems - The Representation Problem2002In: Promote IT 2002, 2002Conference paper (Other academic)
  • 132.
    Odelstad, Jan
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Boman, M
    Algebras for Agent Norm-Regulation2004In: Annals of Mathematics and Artificial Intelligence, ISSN 1012-2443, E-ISSN 1573-7470, Vol. 42, no 1-3, p. 141-160Article in journal (Refereed)
    Abstract [en]

    An abstract architecture for idealized multi-agent systems whose behaviour is regulated by normative systems is developed and discussed. Agent choices are determined partially by the preference ordering of possible states and partially by normative considerations: The agent chooses that act which leads to the best outcome of all permissible actions. If an action is non-permissible depends on if the result of performing that action leads to a state satisfying a condition which is forbidden, according to the norms regulating the multi-agent system. This idea is formalized by defining set-theoretic predicates characterizing multi-agent systems. The definition of the predicate uses decision theory, the Kanger-Lindahl theory of normative positions, and an algebraic representation of normative systems.

  • 133.
    Odelstad, Jan
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Lindahl, L
    The Role of Connections as Minimal Norms in Normative Systems2002In: Legal Knowledge and Information Systems / [ed] Trevor Bench-Capon, 2002Conference paper (Other academic)
  • 134.
    Ohlsson, P
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Real-time Rendering of Accumulated Snow2004In: Proceedings of the Annual SIGRAD Conference, 2004, p. 25-32Conference paper (Other academic)
  • 135.
    Ollila, Mark
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Carling, Eva
    University of Gävle, Central University Administration.
    Bringing art into computer graphics education2000In: Computers & graphics, ISSN 0097-8493, E-ISSN 1873-7684, Vol. 24, no 4, p. 617-622Article in journal (Refereed)
    Abstract [en]

    This paper presents an innovative education program at the University of Gävle, Sweden. The program, creative programming, combines traditional methods of teaching computer graphics, with other cross-disciplinary areas such as art, cognition, and film. The uniqueness of the program is represented by the students who are accepted and the teaching environment they are put in. A judicial process is used to screen applicants, with and without portfolios to the program. This is followed by an examination of intellectual capacity, practical examination, and finally an interview. Together, these are used as guidelines to determine if the student is a suitable candidate for the program. The final group selected has varying backgrounds, ranging from the professional artist to the traditional computer scientist. They are then immersed in a lab environment for the whole duration of the education on the campus. The remainder of the education involves a period in industry. The combination of selective students, a lab environment has produced very satisfactory results, and can be used as basis for further developing the education.

  • 136.
    Olsson, Björn
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Hast, Anders
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Ynnerman, Anders
    A Novel Approach to Compress Reflection Functions Based on PCA2005In: Sigrad 2005, 2005, p. 51-56Conference paper (Refereed)
  • 137. Olsson, E
    et al.
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Jansson, A
    Safer navigation at sea using augmented reality2002In: Proceedings of HCI'02, People and Computers, 2002, p. 154-157Conference paper (Other academic)
  • 138.
    Olsson, Fredrik
    et al.
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Borg, Johannes
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Utvärdering av 3D-positionsmätning baserad på IR-kamera tracking med Wii Remote2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Under det senaste halvåret har Nintendos Wii Remote uppmärksammats av forskare välden över. Det som är intressant är att den går att använda på en vanlig dator med Bluetooth och med hjälp av Wiimotens IR-kamera går det att skapa en motsvarighet till tryckkänsliga skärmar och dynamiskt genererade 3D-projektioner. För att göra detta krävs det metoder för triangulering av 3D-positioner. Detta examensarbete går ut på att ut-värdera Wiimotens tekniska prestanda för att se om den är tillräcklig för sådana applikationer. Till detta ingår även att ta fram metoder för triangulering och mätning av 3D-positioner. Resultaten tyder på att Wiimotens prestanda är tillräcklig för att göra 3D-positionsmätning i samband med tracking. Dock begränsas dess användningsområde till mindre ytor.

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  • 139.
    Olsson, Johan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Streaming och nätverk för digital skyltning2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Idag finns som alltid behovet att distribuera media. Allt eftersom prestandan för överföring av information i dator-nätverk har ökat har detta blivit möjligt genom streaming, strömmande media. Detta innebär att klienten inte behöver ladda ner hela materialet för att kunna se eller lyssna på det. Allt eftersom kravet på kvalitén av materialet ökar blir kraven på nätverket högre. Precisallt Media AB är ett företagsom sysslar med digital skyltning. För att nå ut med film till sina skyltar som finns i olika butiker och varuhus, schemaläggs och skickas film till en vanlig pc som sköter skylten. Lagring av video sker lokalt, det vill säga materialet som spelas upp på en skylt är lagrat på samma dator som spelar upp det. Detta är ingen effektiv lösning eftersom överföringen av material som sker över Internet måste ske till varje dator som ska spela upp det. Går det att skapa en effektivare lösning genom att använda streaming hos kunden? Och går det att effektivisera distribueringen av media tillkundens nätverk?

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  • 140. Parus, Jindrich
    et al.
    Kolingerová, Ivana
    Hast, Anders
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Fast Computation of Vertex Normals for Linearly Deforming Meshes2007In: Journal of Graphics Tools, ISSN 1086-7651, Vol. 12, no 4, p. 47-58Article in journal (Refereed)
  • 141. Parus, Jindřich
    et al.
    Hast, Anders
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Kolingerová, Ivana
    Temporal Face Normal Interpolation2006In: SIGRAD 2006, Linköping: Linköpings universitet , 2006, p. 12-16Conference paper (Refereed)
    Abstract [en]

    Normals of triangular faces are essential vectors in many area of computer graphics. In this paper we will deal with methods for normal computation of triangles under linear soft-body deformation.

  • 142.
    Pettersson, Carina
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Computers for the many: A survey of computer use in Swedish homes2005In: ICT capabilities in action: what people do : user aspects of ICTs Work Group reports - No 2 of 3 / [ed] Enid Mante-Meijer and Lajla Klamer, Luxemburg: Office for Official Publications of the European Communities , 2005, p. 117-131Chapter in book (Other academic)
  • 143. Pettersson, L W
    et al.
    Jensen, N
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    A Virtual Laboratory for Computer Graphics Education2003In: Proceedings of EUROGRAPHICS Conference 2003, Granada, Spain. 1-6 September 2003, 2003, p. 17-21Conference paper (Other academic)
  • 144. Pettersson, L W
    et al.
    Kjellin, A
    Lind, M
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Effects of layer partitioning in collaborative 3D visualizations2006In: Advances in Visual Computing: Second International Symposium, ISVC 2006 Lake Tahoe, NV, USA, November 6-8, 2006 Proceedings, Part I, Berlin, Heidelberg: Springer , 2006, p. 180-190Conference paper (Other academic)
    Abstract [en]

    Display technologies that support multiple independent views of the same co-located 3D visualization volume make new forms of collaboration possible. In this field of research, until now most efforts have focused on technical solutions and their applications. The main contribution of this paper is the results from a study comparing integral and partitioned 3D content in a head coupled stereoscopic environment through independent views of a shared 3D visualization.

    In our study we used a geospatial task that was solved by ten pairs of collaborating individuals (dyads). We measured task performance by time and error rate for the dyads in two main conditions: a) an integral visualization that presented a map in the display surface and four layers at different depths below the display surface to each of the observers, and b) a partitioned visualization, where two mutually exclusive subsets of the layers were presented to each of the observers together with the map in the display surface.

    The results from the study showed significant differences in regard to performance times between the two conditions. Task performance was significantly better in the condition with layer partitioning. Partitioned visualizations can thus, at least in some cases, improve performance in tasks requiring collaboration between users.

  • 145. Pettersson, L W
    et al.
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Collaborative 3D Visualizations of Geo-Spatial Information for Command and Control2004In: Proceedings of the Annual SIGRAD Conference, 2004, p. 41-47Conference paper (Other academic)
  • 146. Pettersson, L W
    et al.
    Wesslén, Daniel
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    In situ tomographic display for interactive data visualization2004In: Proceedings of the third Nordic conference on Human-Computer Interaction, 2004Conference paper (Other academic)
    Abstract [en]

    With tomographic in situ visualization we present a novel approach to interactive data visualization and exploration. This visualization concept is useful for presentation of spatially co-located information that is normally not visible to the human's eye. The tomographic in situ display allows for interactive cutting through data in space by using a spatially tracked and calibrated display. In this paper we describe the technical apparatus of our prototype and describe an application for the tomographic in situ visualization in the field of indoor climate studies.

  • 147. Pettersson, Lars Winkler
    et al.
    Lind, M
    Spak, Ulrik
    Seipel, Stefan
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Visualization of symbols in a horizontal multiple viewer 3D display environment2005In: Proceedings of IEEE Information Visualization 2005, 2005, p. 357-362Conference paper (Other academic)
    Abstract [en]

    In this paper we present a visualization environment for collaborative and co-located displays of geospatially related data for command and control. We first describe the working principle of a novel horizontal display that is aimed at providing high resolution stereoscopic 3D visualizations simultaneously to a group of up to four observers. This display environment opens up new ways to present view-dependent visual content within a shared workspace. For this environment we propose frontoparallel presentations of conventional symbols that are 3D presentations of 2D symbols which appear virtually oriented towards the line of sight of the observer. In an experiment we compare frontoparallel symbols with flat symbols i.e. symbols that are presented in the horizontal plane of the display. The results of our study indicate that frontoparallel symbols in a stereoscopic view are perceived and identified faster than symbols presented flat in relation to the plane of the display.

  • 148.
    Rashidi, Danial
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Game Character: Concept to product2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A production pipeline of different game companies is explored with the idea of creating characters specifically designed for games. A character was created following the different components of a real game studio which produced a low poly count character that could be implemented into a game from a technical and aesthetic point of view. An aim of this research paper was to obtain a better understanding of how the idea of a game character is developed and also why industry professionals utilize some techniques and not others. A finished game character model was created from the design process concept stage to the final product for an online game contest.

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  • 149. Rigasand, G
    et al.
    Carling, Eva
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Brehmer, B
    Reliability and validity of performance measures in microworlds2002In: Intelligence, ISSN 0160-2896, E-ISSN 1873-7935, Vol. 30, no 5, p. 463-480Article in journal (Other academic)
    Abstract [en]

    Research with microworlds enable us to study complex mental processes in semantically rich but standardized environments, under more realistic conditions than ordinary tests do. Moreover, adapting the microworlds to the needs of mental testing may increase our ability to predict success in real life pursuits [Rigas, G., & Brehmer, B. (1999). Mental processes in intelligence tests and dynamic decision making tasks. In P. Juslin & H. Montgomery (Eds.), Judgement and decision making: Neo-Brunswikean and process-tracing approaches (pp. 45-65). Hillsdale, NJ: Lawrence Erlbaum Associates.]. Yet earlier studies have found no relations between intelligence test scores and microworld performance. The relationships between two real time dynamic decision making tasks (microworlds) and one intelligence test were investigated. The participants interacted with eight NEWFIRE scenarios, four COLDSTORE scenarios, and completed Raven's Advanced Progressive Matrices (APM). The composite scores of performance in the two microworlds were sufficiently reliable. APM was a predictor of success in these two microworlds. Statistically significant increases in R 2 were obtained. Methodological problems in research with microworlds are discussed and changes related to the adaptation of microworlds to the needs of mental testing are proposed.

  • 150. Roitto, M.
    et al.
    Strömmer, R.
    Ahonen-Jonnarth, Ulla
    University of Gävle, Department of Mathematics, Natural and Computer Sciences, Ämnesavdelningen för datavetenskap.
    Hyvärinen, M.
    Markkola, A. M.
    Does the lichen mat alleviate the effects of wet deposited nickel on soil microorganisms and Scots pine (Pinus sylvestris L.) seedlings?2001In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 230, no 2, p. 267-277Article in journal (Refereed)
    Abstract [en]

    A field experiment was conducted in a dry heath forest dominated by Scots pine (Pinus sylvestris L.) and a mat-forming lichen (Cladina stellaris (Opiz) Brodo) to assess the effect of wet-deposited nickel (Ni) on pine seedlings and soil microorganisms, and to explore whether an intact lichen mat could act as a buffer against heavy metal deposits. Pine seedlings were planted in quadrats covered by a natural lichen layer and in quadrats from which the lichen layer had been completely removed. The quadrats were exposed to four levels of Ni deposition: 0 (i.e., distilled water), 10, 100 and 1000 mg m-2 year-1 in two growing seasons. Increasing Ni deposition led to an increase in the Ni content of the needles, roots and the soil organic layer. The lichen mat reduced Ni flow to the organic soil layer, but had no significant, reducing effect on needle or root Ni concentration. The most severe Ni treatment had detrimental effects on seedling growth and increased peroxidase activity in the previous years needles. Removal of the lichen layer did not increase susceptibility of seedlings to Ni. Values of maximal carbon use efficiency (Max) and metabolic quotient (qCO2) of the soil microorganisms indicated protective value of the lichen mat to soil microorganisms at the highest Ni treatment. Skimming per se decreased basal respiration, qCO2 and concentrations of potassium in the soil and also increased the lag period of the microorganisms as a response to in situ substrate addition.

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