hh.sePublications
Change search
Refine search result
1234567 1 - 50 of 1910
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abdulrazzaq, Mohammed
    et al.
    Halmstad University, School of Information Technology.
    Wei, Yuan
    Halmstad University, School of Information Technology.
    Industrial Control System (ICS) Network Asset Identification and Risk Management2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Setting against the significant background of Industrial 4.0, the Industrial Control System (ICS) accelerates and enriches the upgrade the existing production infrastructure. To make the infrastructures “smart”, huge parts of manual operations have been automated in this upgrade and more importantly, the isolated controlled processes have been connected through ICS. This has also raised the issues in asset management and security concerns. Being the starting point of securing the ICS, the asset identification is, nevertheless, first dealt by exploring the definition of assets in the ICS domain due to insufficient documentation and followed by the introduction of ICS constituents and their statuses in the whole network. When the definition is clear, a well-received categorization of assets in the ICS domain is introduced, while mapping out their important attributes and their significance relating the core of service they perform. To effectively tackle the ever-increasing amount of assets, identification approaches are compared and a case study was performed to test the effectiveness of two open source software. Apart from the identification part, this thesis describes a framework for efficient asset management from CRR. The four cyclic modules proposed give an overview on how the asset management should be managed according the dynamics of the assets in the production environment.

  • 2.
    Abrahamsson, Ida
    et al.
    Halmstad University, School of Teacher Education (LUT).
    Wahlqvist, Teresia
    Halmstad University, School of Teacher Education (LUT).
    Vilket arbetssätt gynnar förmågan att kommunicera matematik?2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 3.
    Aceto, L.
    et al.
    School of Computer Science, Reykjavik University, Iceland.
    Birgisson, A.
    Department of Computer Science and Engineering, Chalmers University of Technology, Sweden.
    Ingolfsdottir, A.
    School of Computer Science, Reykjavik University, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, TU/Eindhoven, Eindhoven, Netherlands.
    Decompositional Reasoning about the History of Parallel Processes2011In: Fundamentals of software engineering: revised selected papers, Heidelberg: Springer Berlin/Heidelberg, 2011, Vol. 4171, p. 32-47Conference paper (Refereed)
    Abstract [en]

    This paper presents a decomposition technique for Hennessy-Milner logic with past and its extension with recursively defined formulae. In order to highlight the main ideas and technical tools, processes are described using a subset of CCS with parallel composition, nondeterministic choice, action prefixing and the inaction constant. The study focuses on developing decompositional reasoning techniques for parallel contexts in that language. © 2012 Springer-Verlag.

  • 4.
    Aceto, L.
    et al.
    School of Computer Science, Reykjavík University, Kringlan 1, 103 Reykjavík, Iceland.
    Fokkink, W. J.
    Department of Computer Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands.
    Ingólfsdóttir, A.
    School of Computer Science, Reykjavík University, Kringlan 1, 103 Reykjavík, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands.
    Lifting non-finite axiomatizability results to extensions of process algebras2010In: Acta Informatica, ISSN 0001-5903, E-ISSN 1432-0525, Vol. 47, no 3, p. 147-177Article in journal (Refereed)
    Abstract [en]

    This paper presents a general technique for obtaining new results pertaining to the non-finite axiomatizability of behavioural (pre)congruences over process algebras from old ones. The proposed technique is based on a variation on the classic idea of reduction mappings. In this setting, such reductions are translations between languages that preserve sound (in)equations and (in)equational provability over the source language, and reflect families of (in)equations responsible for the non-finite axiomatizability of the target language. The proposed technique is applied to obtain a number of new non-finite axiomatizability theorems in process algebra via reduction to Moller's celebrated non-finite axiomatizability result for CCS. The limitations of the reduction technique are also studied. In particular, it is shown that prebisimilarity is not finitely based over CCS with the divergent process Ω, but that this result cannot be proved by a reduction to the non-finite axiomatizability of CCS modulo bisimilarity. This negative result is the inspiration for the development of a sharpened reduction method that is powerful enough to show that prebisimilarity is not finitely based over CCS with the divergent process Ω. © 2010 Springer-Verlag.

  • 5.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University, Menntavegur 1, IS-101 Reykjavik, Iceland.
    Birgisson, Arnar
    Department of Computer Science and Engineering, Chalmers University of Technology, Sweden.
    Ingolfsdottir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University, Menntavegur 1, IS-101 Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, Netherlands.
    Reniers, Michel A.
    Department of Computer Science, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, Netherlands.
    Rule Formats for Determinism and Idempotence2012In: Science of Computer Programming, ISSN 0167-6423, E-ISSN 1872-7964, Vol. 77, p. 889-907Article in journal (Refereed)
    Abstract [en]

    Determinism is a semantic property of (a fragment of) a language that specifies that a program cannot evolve operationally in several different ways. Idempotence is a property of binary composition operators requiring that the composition of two identical specifications or programs will result in a piece of specification or program that is equivalent to the original components. In this paper, we propose (related) meta-theorems for guaranteeing the determinism and idempotence of binary operators. These meta-theorems are formulated in terms of syntactic templates for operational semantics, called rule formats. In order to obtain a powerful rule format for idempotence, we make use of the determinism of certain transition relations in the definition of the format for idempotence. We show the applicability of our formats by applying them to various operational semantics from the literature. © 2010 Elsevier B.V. All rights reserved.

  • 6.
    Aceto, Luca
    et al.
    School of Computer Science, Reykjavik University, Iceland.
    Birgisson, Arnar
    School of Computer Science, Reykjavik University, Iceland & Department of Computer Science and Engineering, Chalmers University of Technology, Sweden.
    Ingólfsdóttir, Anna
    School of Computer Science, Reykjavik University, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, TU/Eindhoven, Eindhoven, Netherlands.
    Decompositional Reasoning about the History of Parallel Processes2010Report (Other academic)
    Abstract [en]

    Decompositional reasoning aims at automatically decomposing a global property of a composite system into local properties of (possibly unknown) components. In concurrency theory, decompositional reasoning techniques date back to the seminal work of Larsen and Liu in the late 1980s and early 1990s. However, we are not aware of any such decomposition technique that applies to reasoning about the "past". In this paper, we address this problem and present a decomposition technique for Hennessy-Milner logic with past and its extension with recursively defined formulae. As a language for processes, we use a subset of Milner's CCS with parallel composition, non-deterministic choice, action prefixing and the inaction constant. We focus on developing decompositional reasoning techniques for parallel contexts in that language.

  • 7.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University, Menntavegur 1, IS 101 Reykjavik, Iceland.
    Cimini, Matteo
    ICE-TCS, School of Computer Science, Reykjavik University, Menntavegur 1, IS 101 Reykjavik, Iceland.
    Ingolfsdottir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University, Menntavegur 1, IS 101 Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, Netherlands.
    Reniers, Michel A.
    Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, Netherlands.
    Rule Formats for Distributivity2012In: Theoretical Computer Science, ISSN 0304-3975, E-ISSN 1879-2294, Vol. 458, p. 1-28Article in journal (Refereed)
    Abstract [en]

    This paper proposes rule formats for Structural Operational Semantics guaranteeing that certain binary operators are left distributive with respect to a set of binary operators. Examples of left-distributivity laws from the literature are shown to be instances of the provided formats. Some conditions ensuring the invalidity of the left-distributivity law are also offered. © 2012 Elsevier B.V. All rights reserved.

  • 8.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University, Menntavegur 1, IS 101 Reykjavik, Iceland.
    Cimini, Matteo
    ICE-TCS, School of Computer Science, Reykjavik University, Menntavegur 1, IS 101 Reykjavik, Iceland.
    Ingolfsdottir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University, Menntavegur 1, IS 101 Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, Netherlands.
    Reniers, Michel A.
    Department of Computer Science, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, Netherlands.
    SOS Rule Formats for Zero and Unit Elements2011In: Theoretical Computer Science, ISSN 0304-3975, E-ISSN 1879-2294, Vol. 412, no 28, p. 3045-3071Article in journal (Refereed)
    Abstract [en]

    This paper proposes rule formats for Structural Operational Semantics guaranteeing that certain constants act as left or right unit/zero elements for a set of binary operators. Examples of left and right zero, as well as unit, elements from the literature are shown to fit the rule formats offered in this study. © 2011 Elsevier B.V. All rights reserved.

  • 9.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Cimini, Matteo
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Ingólfsdóttir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Reniers, Michael A.
    Department of Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands.
    On Rule Formats for Zero and Unit Elements2010Report (Other academic)
    Abstract [en]

    This paper proposes a rule format for Structural Operational Semantics guaranteeing that certain constants act as left or right zero elements for a set of binary operators. Our design approach is also applied to reformulate an earlier rule format for unit elements developed by some of the authors. Examples of left and right zero, as well as unit, elements from the literature are shown to be checkable using the provided formats.

  • 10.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Cimini, Matteo
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Ingólfsdóttir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Reniers, Michael A.
    Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Rule Formats for Distributivity2010Report (Other academic)
    Abstract [en]

    This paper proposes rule formats for Structural Operational Semantics guaranteeing that certain binary operators are left distributive with respect to a set of binary operators. Examples of left-distributivity laws from the literature are shown to be instances of the provided formats.

  • 11.
    Aceto, Luca
    et al.
    School of Computer Science, Reykjavik University, Iceland.
    Cimini, Matteo
    School of Computer Science, Reykjavik University, Iceland.
    Ingólfsdóttir, Anna
    School of Computer Science, Reykjavik University, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, Netherlands.
    Reniers, Michel A.
    Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven, Netherlands.
    Rule Formats for Distributivity2011In: Language and Automata Theory and Applications: 5th International Conference : Proceedings / [ed] Adrian Horia Dediu, Heidelberg: Springer Berlin/Heidelberg, 2011, Vol. 6638, p. 79-90Conference paper (Refereed)
    Abstract [en]

    This paper proposes rule formats for Structural Operational Semantics guaranteeing that certain binary operators are left distributive with respect to a set of binary operators. Examples of left-distributivity laws from the literature are shown to be instances of the provided formats. © 2011 Springer-Verlag.

  • 12.
    Aceto, Luca
    et al.
    Reykjavík University, Kringlan 1, IS-103, Reykjavík, Iceland.
    Fokkink, Wan
    Vrije Universiteit Amsterdam, NL-1081HV, The Netherlands.
    Ingólfsdóttir, Anna
    Reykjavík University, Kringlan 1, IS-103, Reykjavík, Iceland.
    Mousavi, Mohammad Reza
    Eindhoven University of Technology, NL-5600MB Eindhoven, The Netherlands.
    Lifting non-finite axiomatizability results to extensions of process algebras2008In: Fifth Ifip International Conference On Theoretical Computer Science – Tcs 2008 / [ed] Ausiello, G, Karhumaki, J, Mauri, G, Ong, L, New York: Springer-Verlag New York, 2008, Vol. 273, p. 301-316Conference paper (Refereed)
    Abstract [en]

    This paper presents a general technique for obtaining new results pertaining to the non-finite axiomatizability of behavioral semantics over process algebras from old ones. The proposed technique is based on a variation on the classic idea of reduction mappings. In this setting, such reductions are translations between languages that preserve sound (in)equations and (in)equational proofs over the source language, and reflect families of (in)equations responsible for the non-finite axiomatizability of the target language. The proposed technique is applied to obtain a number of new non-finite axiomatizability theorems in process algebra via reduction to Moller’s celebrated non-finite axiomatizability result for CCS. The limitations of the reduction technique are also studied.

  • 13.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Fokkink, Wan J.
    Department of Computer Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
    Ingólfsdóttir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Lifting non-finite axiomatizability results to extensions of process algebras2008Report (Other academic)
  • 14.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Goriac, Eugen-Ioan
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Ingolfsdottir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Reniers, Michel A.
    Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Exploiting Algebraic Laws to Improve Mechanized Axiomatizations2013In: Algebra and Coalgebra in Computer Science: 5th International Conference, Calco 2013, Warsaw, Poland, September 2013, Proceedings, Berlin: Springer Berlin/Heidelberg, 2013, p. 36-50Conference paper (Refereed)
    Abstract [en]

    In the field of structural operational semantics (SOS), there have been several proposals both for syntactic rule formats guaranteeing the validity of algebraic laws, and for algorithms for automatically generating ground-complete axiomatizations. However, there has been no synergy between these two types of results. This paper takes the first steps in marrying these two areas of research in the meta-theory of SOS and shows that taking algebraic laws into account in the mechanical generation of axiomatizations results in simpler axiomatizations. The proposed theory is applied to a paradigmatic example from the literature, showing that, in this case, the generated axiomatization coincides with a classic hand-crafted one. © 2013 Springer-Verlag Berlin Heidelberg.

  • 15.
    Aceto, Luca
    et al.
    School of Computer Science, Reykjavík University, Kringlan 1, 103 Reykjavík, Iceland.
    Ingólfsdóttir, A.
    School of Computer Science, Reykjavík University, Kringlan 1, 103 Reykjavík, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands.
    Reniers, M. A.
    Algebraic properties for free!2009In: Bulletin of the European Association for Theoretical Computer Science, ISSN 0252-9742, Vol. 99, p. 81-103Article in journal (Refereed)
    Abstract [en]

    Algebraic properties specify some natural properties of programming and specification constructs. This paper provides an overview of techniques to guarantee or generate algebraic properties of language constructs by investigating the syntactic shape of the deduction rules defining their operational semantics.

  • 16.
    Aceto, Luca
    et al.
    Department of Computer Science, Reykjavík University, Kringlan 1, IS-103, Reykjavík, Iceland.
    Ingólfsdóttir, Anna
    Department of Computer Science, Reykjavík University, Kringlan 1, IS-103, Reykjavík, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Reykjavík University, Kringlan 1, IS-103, Reykjavík, Iceland.
    Impossibility results for the equational theory of timed CCS2007In: Algebra and Coalgebra in Computer Science: Second International Conference, CALCO 2007, Bergen, Norway, August 20-24, 2007. Proceedings, Berlin: Springer Berlin/Heidelberg, 2007, Vol. 4624, p. 80-95Conference paper (Refereed)
    Abstract [en]

    We study the equational theory of Timed CCS as proposed by Wang Yi in CONCUR'90. Common to Wang Yi's paper, we particularly focus on a class of linearly-ordered time domains exemplified by the positive real or rational numbers. We show that, even when the set of basic actions is a singleton, there are parallel Timed CCS processes that do not have any sequential equivalent and thus improve on the Gap Theorem for Timed CCS presented by Godskesen and Larsen in FSTTCS'92. Furthermore, we show that timed bisimilarity is not finitely based both for single-sorted and two-sorted presentations of Timed CCS. We further strengthen this result by showing that, unlike in some other process algebras, adding the untimed or the timed left-merge operator to the syntax and semantics of Timed CCS does not solve the axiomatizability problem.

  • 17.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Ingólfsdóttir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University, Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Reniers, Michel A.
    Department of Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands.
    A Rule Format for Unit Elements2009Report (Other academic)
    Abstract [en]

    This paper offers a meta-theorem for languages with a Structural Operational Semantics (SOS) in the style of Plotkin. Namely, it proposes a generic rule format for SOS guaranteeing that certain constants act as left- or right-unit elements for a set of binary operators. We show the generality of our format by applying it to a wide range of operators from the literature on process calculi.

  • 18.
    Aceto, Luca
    et al.
    ICE-TCS, School of Computer Science, Reykjavik University Kringlan 1, IS-103 Reykjavik, Iceland.
    Ingólfsdóttir, Anna
    ICE-TCS, School of Computer Science, Reykjavik University Kringlan 1, IS-103 Reykjavik, Iceland.
    Mousavi, Mohammad Reza
    Department of Computer Science, Eindhoven University of Technology P.O. Box 513, NL-5600 MB Ei ndhoven, The Netherlands.
    Reniers, Michel A.
    Department of Computer Science, Eindhoven University of Technology P.O. Box 513, NL-5600 MB Ei ndhoven, The Netherlands.
    A rule format for unit elements2010In: SOFSEM 2010: Theory and Practice of Computer Science: Proceedings / [ed] VanLeeuwen, J, Muscholl, A, Peleg, D, Pokorny, J, Rumpe, B, Berlin: Springer Berlin/Heidelberg, 2010, Vol. 5901, p. 141-152Conference paper (Refereed)
    Abstract [en]

    This paper offers a meta-theorem for languages with a Structural Operational Semantics (SOS) in the style of Plotkin. Namely, it proposes a generic rule format for SOS guaranteeing that certain constants act as left- or right-unit elements for a set of binary operators. We show the generality of our format by applying it to a wide range of operators from the literature on process calculi.

  • 19.
    Aceto, Luca
    et al.
    Reykjavik University, Reykjavik, Iceland.
    Mousavi, Mohammad RezaEindhoven University of Technology, Eindhoven, The Netherlands.
    Proceedings First International Workshop on Process Algebra and Coordination2011Conference proceedings (editor) (Other academic)
    Abstract [en]

    Process algebra provides abstract and rigorous means for studying communicating concurrent systems. Coordination languages also provide abstract means for the specifying and programming communication of components. Hence, the two fields seem to have very much in common and the link between these two research areas have been established formally by means of several translations, mainly from coordination languages to process algebras. There have also been proposals of process algebras whose communication policy is inspired by the one underlying coordination languages. The aim of this workshop was to push the state of the art in the study of the connections between process algebra and coordination languages by bringing together experts as well as young researchers from the two fields to communicate their ideas and findings. It includes both contributed and invited papers that have been presented during the one day meeting on Process Algebra and Coordination (PACO 2011) which took place on June 9, 2011 in Reykjavik, Iceland.

  • 20.
    Adam, Rania E.
    et al.
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Chalangar, Ebrahim
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Pirhashemi, Mahsa
    Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
    Pozina, Galia
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Liu, Xianjie
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Palisaitis, Justinas
    Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Department of Sciences and Technology, Linköping University, Norrköping, Sweden & Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Willander, Magnus
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Nur, Omer
    Department of Sciences and Technology, Linköping University, Norrköping, Sweden.
    Graphene-based plasmonic nanocomposites for highly enhanced solar-driven photocatalytic activities2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 52, p. 30585-30598Article in journal (Refereed)
    Abstract [en]

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

  • 21.
    Aderklint, Denice
    Halmstad University, School of Business, Engineering and Science.
    Legal Support for a Resilient Stormwater Management: Review of Swedish Regulations and Objectives2017Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Sustainability entails a system that has the capacity to sustain itself. Stormwater management is one part of the concept sustainable development but traditional practices entail adverse effects on social-ecological systems and there is a need for increasing the resilience of urban stormwater systems.  The growing pressure from climate change and intensified urbanization increase the need for stormwater management. If poorly managed the security and functioning of societies will be negatively affected. Regulations are essential in the achievement of sustainable urban environments. However, national regulations concerning stormwater management are spread through different legal frameworks from different times and it has been recognized that the spread could challenge implementation of the regulations and climate change adaptation. Administrative instruments are important to support the social, economic and ecological value of green and blue structures. The thesis target to analyze relevant regulations and investigate their effectiveness for a sustainable stormwater management through combined interpretation methods based on the intention behind the law and their function in society. The thesis claims that consequences of poorly regulated sustainable stormwater management results in an inefficient use of resources and pose a risk for the environment. Sustainable development is not visible in any article in the Law on General Water Services and it therefore risk to be overlooked in practice. The issues of urban stormwater need to be more integrated in the municipal work and planning processes.

    The analysis reveals that there is support for resilient stormwater management when there is a combination of up-to date research and an objective teleological interpretation. As the shift towards sustainable urban environments entails several aspects, the use of administrative instruments is one important strategy in ensuring urban resilience.

  • 22.
    Adriansson, Emma
    et al.
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Environmental Science.
    Turesson, Linnéa
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS), Environmental Science.
    Klimatanalys av avloppsreningsverk: Analyser av två av Laholmsbuktens VA:s avloppsreningsverk med förslag på förbättringsåtgärder2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The intensified greenhouse effect is the biggest cause for a negative climate change. Global warming is a result of enhanced greenhouse effect and poses a potential threat for humans and its surrounding environment that can result in disastrous consequences. The rise in temperature is driven by increased human activity whereas the leading cause for emissions of greenhouse gases is the combustion of fossil fuels. The prominent source of emissions is from the following sectors: transport, industrial and energy. The task of reducing the emissions of greenhouse gases is both globally and internationally prioritized. Progress has been made although every potential source for emissions has to be investigated in order to reduce the total climate impact. Based on scientific research, wastewater treatment plants are also a contributing factor to the greenhouse effect by emissions of gases. This bachelor’s thesis is investigating two wastewater treatment plants and identifying which processes contribute to the climate impact. The climate impact is calculated with an Excel-based analyzing tool and the results show the Carbon Footprints for the treatment plants. The purpose of this paper is to present result acquired from the treatment plants and identify the processes that have the biggest impact on our climate. Afterwards, solutions derived from the analysis of results will be suggested to improve and bring additional help to the treatment plants with their climate work. In conclusion, it is determined that the treatment plants both have net emissions of greenhouse gases. The biggest contributor is the wastewater treatment and the use of biogas. Results from analysis show that some of the assumptions on emissions made in the tool make the initial results doubtful. Therefore, further research is needed on this subject in order to produce more reliable facts.

  • 23.
    Aerts, Arend
    et al.
    Control Systems Technology Group, Eindhoven University of Technology, Eindhoven, The Netherlands.
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Reniers, Michel A.
    Control Systems Technology Group, Eindhoven University of Technology, Eindhoven, The Netherlands.
    A Tool Prototype for Model-Based Testing of Cyber-Physical Systems2015In: Theoretical Aspects of Computing – ICTAC 2015: 12th International Colloquium Cali, Colombia, October 29–31, 2015, Proceedings / [ed] Martin Leucker, Camilo Rueda, and Frank D. Valencia, Cham: Springer, 2015, Vol. 9399, p. 563-572Conference paper (Refereed)
    Abstract [en]

    We report on a tool prototype for model-based testing of cyber-physical systems. Our starting point is a hybrid-system model specified in a domain-specific language called Acumen. Our prototype tool is implemented in Matlab and covers three stages of model-based testing, namely, test-case generation, test-case execution, and conformance analysis. We have applied our implementation to a number of typical examples of cyber-physical systems in order to analyze its applicability. In this paper, we report on the result of applying the prototype tool on a DC-DC boost converter. © Springer International Publishing Switzerland 2015

  • 24.
    Aerts, Arend
    et al.
    Eindhoven University of Technology, Eindhoven, The Netherlands.
    Reniers, Michel A.
    Eindhoven University of Technology, Eindhoven, The Netherlands.
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Model-Based Testing of Cyber-Physical Systems2016In: Cyber-Physical Systems: Foundations, Principles and Applications / [ed] H. Song, D.B. Rawat, S. Jeschke, and Ch. Brecher, Saint Louis: Elsevier, 2016, p. 287-304Chapter in book (Refereed)
    Abstract [en]

    Cyber-physical systems (CPSs) are the result of the integration of connected computer systems with the physical world. They feature complex interactions that go beyond traditional communication schemes and protocols in computer systems. One distinguished feature of such complex interactions is the tight coupling between discrete and continuous interactions, captured by hybrid system models.

    Due to the complexity of CPSs, providing rigorous and model-based analysis methods and tools for verifying correctness of such systems is of the utmost importance. Model-based testing (MBT) is one such verification technique that can be used for checking the conformance of an implementation of a system to its specification (model).

    In this chapter, we first review the main concepts and techniques in MBT. Subsequently, we review the most common modeling formalisms for CPSs, with focus on hybrid system models. Subsequently, we provide a brief overview of conformance relations and conformance testing techniques for CPSs. © 2017 Elsevier Inc. All rights reserved.

  • 25.
    Afrim, Cerimi
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Norén, Joakim
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Motåtgärder vid IT-forensisk liveanalys2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Live Analysis is a concept that in this paper means analyzing a computer system while it is running. This can be done for several reasons, such as when there is a risk that the system has encryption which can be activated when the system shuts down. Otherwise, it is common if you want to examine network connections, active processes or other phenomena that can be volatile, i.e. disappear when the system shuts down. This work will focus on countermeasures to live forensic analysis and describe different methods and strategies that can be used for these countermeasures. For example, we wrote a program that automatically shuts down the system when you insert a USB memory stick or any other media. These are usually the media which you have your forensic programs on when you do a live analysis. Other important elements of the work are the use of encryption, timestamps and malicious code for challenging live analysis. Our analysis of the topic shows that it is relatively easy to prevent that a live analysis can be performed in a reliable way.

  • 26.
    Agelis, Sacki
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Jacobsson, Sofia
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Alping, Arne
    Ericsson Microwave Systems, Mölndal, Sweden.
    Ligander, Per
    Ericsson Microwave Systems, Mölndal, Sweden.
    Modular interconnection system for optical PCB and backplane communication2002In: Parallel and Distributed Processing Symposium., Proceedings International, IPDPS 2002, Abstracts and CD-ROM, Los Alamitos, Calif.: IEEE Press, 2002, p. 245-250Conference paper (Refereed)
    Abstract [en]

    This paper presents a way of building modular systems with a powerful optical interconnection network. Each module, placed on a Printed Circuit Board (PCB), has a generic optical communication interface with a simple electronic router. Together with optical switching using micro-electromechanical system (MEMS) technology, packet switching over reconfigurable topologies is possible. The interconnection system gives the possibility to integrate electronics with optics without changing existing PCB technology. Great interest from industry is therefore expected and the cost advantages are several: reuse of module designs, module upgrades without changing the PCB, low-cost conventional PCB technology, etc. In the version described in this paper, the interconnection system has 48 bidirectional optical channels for intra-PCB communication on each board. For inter-PCB communication, a backplane with 192 bidirectional optical channels supports communication between twelve PCBs. With 2.5 Gbit/s per optical channel in each direction, the aggregated intra-PCB bit rate is 120 Gbit/s full duplex (on each PCB) while the aggregated inter-PCB bit rate is 480 Gbit/s full duplex. A case study shows the feasibility of the interconnection system in a parallel processing system for radar signal processing.

  • 27.
    Agelis, Sacki
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Optoelectronic router with a reconfigurable shuffle network based on micro-optoelectromechanical systems2004In: Journal of Optical Networking, ISSN 1536-5379, Vol. 4, no 1, p. 1-10Article in journal (Refereed)
    Abstract [en]

    An optoelectronic router with a shuffle exchange network is presented and enhanced by the addition of micro-optoelectromechanical systems (MOEMS) in the network to add the ability to reconfigure the shuffle network. The MOEMS described here are fully connected any-to-any crossbar switches. The added reconfigurability provides the opportunity to adapt the system to different common application characteristics. Two representative application models are described: The first has symmetric properties, and the second has asymmetric properties. The router system is simulated with the specified applications and an analysis of the results is carried out. By use of MOEMS in the optical network, and thus reconfigurability, greater than 50% increased throughput performance and decreased average packet delay are obtained for the given application. Network congestion is avoided throughout the system if reconfigurability is used.

  • 28.
    Agelis, Sacki
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Optoelectronic router with MOEMS–based reconfigurable shuffle network2004Conference paper (Refereed)
  • 29.
    Aghaeipour, Mahtab
    Lund University, Lund, Sweden.
    Tailoring the Optical Response of III-V Nanowire Arrays2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Semiconductor nanowires show a great deal of promise for applications in a wide range of important fields, including photovoltaics, biomedicine, and information technology. Developing these exciting applications is strongly dependent on understanding the fundamental properties of nanowires, such as their optical resonances and absorption spectra. In this thesis we explore optical absorption spectra of arrays of vertical III-V nanowires with a special emphasis on structures optimized to enhance absorption in the solar spectrum. First, we analyze experimentally determined absorption spectra of both indium phosphide (InP) and gallium phosphide (GaP) nanowire arrays. The study provides an intuitive understanding of how the observed absorption resonances in the nanowires may be tuned as a function of their geometrical parameters and crystal structure. As a consequence, the spectral position of absorption resonances can be precisely controlled through the nanowire diameter. However, the results highlight how the blue-shift in the optical absorption resonances as the diameter of the nanowires decreases comes to a halt at low diameters. The stop point is related to the behavior of the refractive indices of the nanowires. The wavelength of the stop is different for nanowire polytypes of similar dimensions due to differences in their refractive indices. We then present a theoretical argument that it is important to consider symmetry properties when tailoring the optical modes excited in the nanowires for enhanced absorption. We show that absorption spectra may be enhanced compared to vertical nanowires at normal incidence by tilting the nanowires with normal incidence light, or by using off-normal incidence with vertical nanowires. This is because additional optical modes inside the nanowires are excited when the symmetry is broken. Looking forward to omnidirectional applications, we consider branched nanowires as a way to enhance the absorption spectra at normal incidence by taking advantage of simultaneous excitation of the spectrally different optical modes in the branches and the stems. Third, we describe in theoretical terms how integrating distributed Bragg reflectors (DBRs) with the nanowires can improve absorption spectra compared to conventional nanowires. DBRs provide a way to employ light trapping mechanisms which increases the optical path length of the excited modes and thereby improves the absorption of the excited modes. At normal incidence, DBR-nanowires improve the absorption efficiency to 78%, compared to 72% for conventional nanowires. We show that the efficiency is increased to 85% for an off-normal incident angle of 50˚. Overall, our results show that studies of optical resonances in nanowires that take the light-matter interaction into account provide opportunities to develop novel optical and optoelectronic functionalities in nanoscience and nanotechnology.

  • 30.
    Aghaeipour, Mahtab
    et al.
    Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab. Lund University, Lund, Sweden.
    Enhanced broadband absorption in nanowire arrays with integrated Bragg reflectors2018In: Nanophotonics, E-ISSN 2192-8614, Vol. 7, no 5, p. 819-825Article in journal (Refereed)
    Abstract [en]

    A near-unity unselective absorption spectrum is desirable for high-performance photovoltaics. Nanowire arrays are promising candidates for efficient solar cells due to nanophotonic absorption resonances in the solar spectrum. The absorption spectra, however, display undesired dips between the resonance peaks. To achieve improved unselective broadband absorption, we propose to enclose distributed Bragg reflectors (DBRs) in the bottom and top parts of indium phosphide (InP) nanowires, respectively. We theoretically show that by enclosing only two periods of In0.56Ga0.44As/InPDBRs, an unselective 78% absorption efficiency (72% for nanowires without DBRs)is obtained at normal incidence in the spectral range from 300 nm to 920 nm. Under oblique light incidence, the absorption efficiency is enhanced up to about 85% at an incidence angle of 50º. By increasing the number of DBR periods from two to five, the absorption efficiency is further enhanced up to 95% at normal incidence. In this work we calculated optical spectra for InP nanowires, but the results are expected to be valid for other direct band gap III-V semiconductor materials. We believe that our proposed idea of integrating DBRs in nanowires offers great potential for high-performance photovoltaic applications. ©2018 Håkan Pettersson et al., published by De Gruyter, Berlin/Boston.

  • 31.
    Aghaeipour, Mahtab
    et al.
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Enhanced optical absorption in nanowires over a desire range of wavelengths2017In: MOC2017 : technical digest of the Twenty-Second Microoptics Conference: November 19-22, 2017, Institute of Industrial Science, The University of Tokyo, Japan, 2017, Vol. 2017-November, p. 360-361Conference paper (Refereed)
    Abstract [en]

    Engineering optical absorption in nanowires, over a desire range of wavelengths is of importance to design high-performance nanowire-based photovoltaics. To this end, we integrate the nanowires with distributed Bragg reflectors to enhance absorption spectra of the nanowires and relate the consequent enhancement to increasing the optical path lengths of the modes. © 2017 The Japan Society of Applied Physics.

  • 32.
    Aghaeipour, Mahtab
    et al.
    Lund University, Lund, Sweden.
    Pistol, Mats-Erik
    Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Lund University, Lund, Sweden.
    Comparative study of absorption efficiency of inclined and vertical InP nanowires2017In: Physics, Simulation, and Photonic Engineering of Photovoltaic Devices VI / [ed] A. Freundlich, L. Lombez, M. Sugiyama, Bellingham, WA: SPIE - International Society for Optical Engineering, 2017, Vol. 10099, article id UNSP 100990SConference paper (Refereed)
    Abstract [en]

    Geometrically designed III-V nanowire arrays are promising candidates for optoelectronics due to their possibility to excite nanophotonic resonances in absorption spectra. Strong absorption resonances can be obtained by proper tailoring of nanowire diameter, length and pitch. Such enhancement of the light absorption is, however, accompanied by undesired resonance dips at specific wavelengths. In this work, we theoretically show that tilting of the nanowires mitigates the absorption dips by exciting strong Mie resonances. In particular, we derive a theoretical optimum inclination angle of about 30 degrees at which the inclined nanowires gain 8% in absorption efficiency compared to vertically standing nanowires in a spectral region matching the intensity distribution of the sun. The enhancement is due to engineering the excited modes inside the nanowires regarding the symmetry properties of the nanowire/light system without increasing the absorbing material. We expect our results to be important for nanowire-based photovoltaic applications. © 2017 SPIE.

  • 33.
    Aghaeipour, Mahtab
    et al.
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Pistol, Mats-Erik
    Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Pettersson, Håkan
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Solid State Physics and NanoLund, Lund University, Lund, Sweden.
    Considering Symmetry Properties of InP Nanowire/Light Incidence Systems to Gain Broadband Absorption2017In: IEEE Photonics Journal, ISSN 1097-5764, E-ISSN 1943-0655, Vol. 9, no 3, article id 4501310Article in journal (Refereed)
    Abstract [en]

    Geometrically designed III-V nanowire arrays are promising candidates for disruptive optoelectronics due to the possibility of obtaining a strongly enhanced absorption resulting from nanophotonic resonance effects. With normally incident light on such vertical nanowire arrays, the absorption spectra exhibit peaks that originate from excitation of HE1m waveguide modes in the constituent nanowires. However, the absorption spectra typically show dips between the absorption peaks. Conventionally, such weak absorption has been counteracted by either making the nanowires longer or by decreasing the pitch of the array, both alternatives effectively increasing the volume of absorbing material in the array. Here, we first study two approaches for compensating the absorption dips by exciting additional Mie resonances: 1) oblique light incidence on vertical InP nanowire arrays and 2) normal light incidence on inclined InP nanowire arrays. We then show that branched nanowires offer a novel route to achieve broadband absorption by taking advantage of simultaneous excitations of Mie resonances in the branches and guided HE1m modes in the stem. Finite element method calculations show that the absorption efficiency is enhanced from 0.72 for vertical nanowires to 0.78 for branched nanowires under normal light incidence. Our work provides new insight for the development of novel efficient photovoltaics with high efficiency and reduced active material volume.

  • 34.
    Ahl, Madeleine
    et al.
    Halmstad University, School of Education, Humanities and Social Science.
    Lundgren, Anton
    Halmstad University, School of Education, Humanities and Social Science.
    Diskussionens kraft: En kvalitativ studie angående hur elever stöttar varandra i gruppsamtal kring naturvetenskapliga fenomen2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Enligt forskning utgör det naturvetenskapliga språket och dess begrepp en betydande del av naturvetenskaplig utbildning, och samtidigt konstateras att det naturvetenskapliga språket och dess begrepp är det största hindret för elevers naturvetenskapliga lärande. Flera forskare hävdar att för att elever skall kunna utveckla begreppsförståelse måste eleverna socialisera med människor som har mer utvecklad språklig kunskap, och då framför allt genom samtal och diskussion av frågor och problem som berör den naturvetenskapliga diskursen. Samtidigt visar forskning att lärande inte per automatik är ett resultat av arbete och samtal i grupp, utan att de sociala och kunskapsmässiga förutsättningarna i grupper är av vikt för hur givande ett gruppsamtal blir.

    Enligt Skolverket skall elever ges möjligheter att samtala och kommunicera samt utveckla sin förmåga att arbeta tillsammans med andra. Därför väcks nyfikenhet kring hur detta gemensamma arbete fortlöper, och om eleverna samarbetar i gruppsamtal. Hur stöttar elever i årskurs 4 och 6 varandra i sina lärandeprocesser i samtal kring frågor om fysikaliska fenomen inom arbetsområdet krafter? Resultatet av denna studie visar att elevers stöttning av varandra sker på ett flertal olika sätt, samt att stöttningen är av betydelse för samtalets utfall och hur givande samtalet blir. Tillsammans kan elever konstruera kunskap kring fenomen och begrepp, om eleverna klarar av att samarbeta och stötta varandra i sina lärandeprocesser. 

  • 35.
    Ahl, Madeleine
    et al.
    Halmstad University, School of Education, Humanities and Social Science.
    Lundgren, Anton
    Halmstad University, School of Education, Humanities and Social Science.
    Hur kan en regndroppe vara sur? Den har väl inga känslor?: En litteraturstudie om hur elevers språk och begreppsförståelse i de naturvetenskapliga ämnena kan utvecklas2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En viktig del av att lära naturvetenskap är att lära sig kommunicera naturvetenskap. Användandet av begrepp i de naturvetenskapliga ämnena förekommer i stor utsträckning, vilket har visat sig hämma elevers utveckling inom dessa ämnen. Ändå slår Skolverket fast att elever skall kunna använda sig av begrepp i den naturvetenskapliga klassrumskommunikationen, och således undersöks i denna litteraturstudie hur arbete med naturvetenskaplig begreppsförståelse kan te sig; vad sägs i den nationella och internationella naturvetenskapsdidaktiska forskningen? Synliggörs arbetsmoment i vilka eleverna får möjlighet att utveckla sin begreppsförståelse? Forskning pekar på vikten av att samtala, och att samtalet skall löpa som en röd tråd genom naturvetenskapliga arbetsmoment, såsom laborationer, där naturvetenskapliga fenomen konkretiseras och synliggörs. Lärarens roll i samtalet är tydlig: den ska syfta till att guida elever genom naturvetenskapens komplexitet och tvetydiga ordförråd genom vardagsnära samtalsämnen, och i förlängningen främja elevers förståelse av och utveckling inom de naturvetenskapliga ämnena.

  • 36.
    Ahlefeldt-Laurvig, Felicia
    Halmstad University, School of Business, Engineering and Science.
    The impact of eutrophic discharge on invertebrate abundance in Fucus communities2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Eutrophication due to enhanced nutrient concentrations can affect marine communities by altering the species composition of macroalgae and marine invertebrates, where certain species have shown tendencies to increase. The aim with this study was to assess how the species composition changed in relation to the distance from a nutrient enriched stream discharge. The study was conducted in an area with rocky shores and Fucus vesiculosus as the dominant alga, and also included the mouth of the eutrophic stream Kvarnabäcken. Macroalgae and invertebrate abundance was examined in eight locations (including an unaffected reference location) at different distances from the mouth of Kvarnabäcken. The concentrations of total nitrogen and total phosphorus were measured in the marine locations as well as in the stream. Although Kvarnabäcken displayed elevated nutrient concentrations, no distinct nutrient gradient was detected in the marine locations due to distance from the stream. The abundance of invertebrates and macroalgae varied to some extent in the locations, where the location in the immediate mouth area showed most differences, which contributed to the conclusion that the direct impact of nutrient discharge is limited. Although there are aspects indicating that the alterations in animal and algae abundance are consequences of nutrient discharge, other factors that regulate community composition must be considered when evaluating eutrophication in marine communities.

  • 37.
    Ahlin, Catharina
    et al.
    Halmstad University, School of Teacher Education (LUT).
    Nilsson, Zandra
    Halmstad University, School of Teacher Education (LUT).
    "Hur tänker du?": en studie om elevers variation av lösningsstrategier inom det pre-algebraiska området2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta är en empirisk studie som har syftat till att synliggöra vilka strategier elever i årskurs två har använt när de löst öppna utsagor samt vilka missuppfattningar som förekommit i samband med detta. Studien har även syftat till att synliggöra hur eleverna har kunnat relatera öppna utsagor till vardagliga sammanhang. Vid datainsamlingen, som utfördes på två olika skolor, genomfördes 15 kvalitativa intervjuer vilka kombinerades med observationer.

    Eftersom det i uppsatsens syfte finns en underförstådd relation till fenomenografin och hermeneutiken i form av såväl teorier som metodologier har dessa forskningsansatser varit en stor inspirationskälla i vår undersökning. Vidare har vi genom vår studie visat att de strategier som elever använder när de löser slutna utsagor till stora delar även används när eleverna löser uppgifter i form av öppna utsagor. Resultatet har visat på en bred variation i elevernas lösningsstrategier och det framgår att eleverna, vid deras lösningar av öppna subtraktionsutsagor, knappt använder de tre vanligaste subtraktionsstrategierna. Istället använder de bland annat en strategi som ger upphov till flera missuppfattningar. Det visade sig även att samtliga elever hade svårt att relatera öppna utsagor till vardagliga sammanhang.

  • 38.
    Ahlqvist Nilsson, Petra
    et al.
    Halmstad University, School of Information Technology.
    Svensson Tynkkynen, Carolin
    Halmstad University, School of Information Technology.
    Förslag på design av digitala knuffar för vägledning2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Decisions are increasingly made in connection with screens, amongst other things due to thecontinuous growth of e-commerce. When people make decisions they are influenced by thechoice environment as well as heuristics and biases, which are mental shortcuts. People areinfluenced by heuristics and biases as it is often difficult for them to make decisions based onall of the information presented. Nudges are a way to guide people to make specific choiceswithout limiting their freedom and have primarily been used in non-digital contexts, but havenow also been introduced in informatics. However, in order for nudges to be able to bedeveloped and used digitally it is important to have knowledge about how people make choicesand the effect nudges have. Previous research on digital nudges also asks for studies on howdigital nudges can be designed and their impact on people's choices online.As nudging is a relatively new term in informatics, as well as research regarding the topic isinquired, this study investigate how digital nudges can be designed to guide people tosustainable choices online. The study was conducted with a design research approach wheredigital nudges were designed based on four different heuristics and biases. The nudges wereapplied on an e-commerce website and tested by means of a prototype. The process fordesigning and evaluating the digital nudges was iterated four or five times to in an exploratoryway test different ways to design the nudges in relation to the research question. The studycontribute with a number of suggestions on how digital nudges can be designed based onheuristics and biases, with guidance and sustainability as focal points.

  • 39.
    Ahlström, Tove
    et al.
    Halmstad University, School of Information Technology.
    Kaikkonen, Amanda
    Halmstad University, School of Information Technology.
    Hur kan ett e-hälsostöd designas för att främja inre motivation till fysisk rehabilitering?2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Due to an increased need for health care, physical rehabilitation is an area where there is a growing need for implementation of e-health support. An unsuccessful rehabilitation plan could potentially lead to a patient's pain or discomfort not being improved as planned. This may lead to the patient needing more rehabilitation care than what had been required if the rehabilitation plan had been completed from the beginning. In addition to this being a cost for the patients themselves, it also entails an extra cost for health care services. Motivation is considered one of the main aspects to take into account as it influences people's ability and willingness to do something. If the motivational aspect is ignored in the design of e- health support in a rehabilitation context, there is a risk that the design will not possess the functions that can be crucial for the user to use the digital support. Although rehabilitation patients are provided with proper physiotherapy exercises they do not perform their exercises, which may be due to their lack of intrinsic motivation. Despite this dilemma, there are few studies that investigate how digital support can be designed to promote intrinsic motivation in a rehabilitation context. The study therefore aimed to examine how an e-health support can be designed to promote intrinsic motivation in a rehabilitation context. The research question was examined using a design-oriented approach. In order to investigate intrinsic motivation, the concept is concretized to the three psychological needs: autonomy, competence and relatedness. The study then resulted in nine design proposals that informed how an e-health support could be designed to promote intrinsic motivation by supporting the three basic psychological needs: autonomy, competence and relatedness.

  • 40.
    Ahmed, Iftikhar
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Farooq, Muhammad
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Switched Multi-hop Priority Queued Networks-Influence of priority levels on Soft Real-time Performance2010Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In the last few years, the number of real-time applications has increased. These applications are sensitive and require the methods to utilize existing network capacity efficiently to meet performance requirements and achieve the maximum throughput to overcome delay, jitter and packet loss. In such cases, when the network needs to support highly interactive traffic like packet-switched voice, the network congestion is an issue that can lead to various problems. If the level of congestion is high enough, the users may not be able to complete their calls and have existing calls dropped or may experience a variety of delays that make it difficult to participate smooth conversation.

    In this paper, we investigate the effect of priority levels on soft real-time performance. We use the priority queues to help us manage the congestion, handle the interactive traffic and improve the over all performance of the system. We consider switched multi-hop network with priority queues. All the switches and end-nodes control the real-time traffic with “Earlier Deadline First” scheduling. The performance of the network is characterized in terms of the average delay, the deadline missing ratio and the throughput.

    We will analyze these parameters with both the bursty traffic and evenly distributed traffic. We will analyze different priority levels and will see how the increase in priority level increases the performance of the soft real-time system.

  • 41.
    Ahmed, Rizwan
    et al.
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Abbas, Shahid
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE).
    Electrical and Optical Characteristics of InP Nanowires based p-i-n Photodetectors2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Photodetectors are a kind of semiconductor devices that convert incoming light to an electrical signal. Photodetectors are classified based on their different structure, fabrication technology, applications and different sensitivity. Infrared photodetectors are widely used in many applications such as night vision, thermal cameras, remote temperature sensing, and medical diagnosis etc.

     

    All detectors have material inside that is sensitive to incoming light. It will absorb the photons and, if the incoming photons have enough energy, electrons will be excited to higher energy levels and if these electrons are free to move, under the effect of an external electric field, a photocurrent is generated.

     

    In this project Fourier Transform Infrared (FT-IR) Spectroscopy is used to investigate a new kind of photodiodes that are based on self-assembled semiconductor nanowires (NWs) which are grown directly on the substrate without any epi-layer. The spectrally resolved photocurrent (at different applied biases) and IV curves (in darkness and illumination) for different temperatures have been studied respectively. Polarization effects (at low and high Temperatures) have been investigated.  The experiments are conducted for different samples with high concentration of NWs as well as with lower concentration of NWs in the temperature range from 78 K (-195ºC) to 300 (27ºC). These photodiodes are designed to work in near infrared (NIR) spectral range.

     

    The results show that the NW photodetectors indeed are promising devices with fairly high break down voltage, change of photocurrent spectra with polarized light, low and constant reverse saturation current (Is). The impact of different polarized light on photocurrent spectra has been investigated and an attempt has been made to clarify the observed double peak of InP photocurrent spectrum. Our investigations also include a comparison to a conventional planar InP p-i-n photodetector.

     

  • 42.
    Ahmethodzic, Amina
    Halmstad University, School of Business, Engineering and Science.
    The effect of strenuous exercise on circulating cytokines2019Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Background: Cytokines are small proteins secreted by white blood cells which play an important part of the immune system. These proteins are secreted due to inflammation which can be caused by infection, cancer and also exercise stress. In this regard the most controversial type of exercise is strenuous exercise. That is why this study focused on this type of exercise in order to bring more knowledge about its effect on immune system, cytokines in particular. Aim: The aim of this research was to study the effects of strenuous exercise on levels of circulating cytokines, and analyze the association of cytokines with baseline fitness and body composition variables. Methods: Thirty recreationally active and healthy male participants were cycling at 70% of their VO2max. Venous blood samples were taken before and after exercise. The serum levels of 37 cytokines were analyzed. Additional variables involved in this study are fitness and body composition as well as temperature measures. Statistical analysis tests used in this study were dependent t-test and Pearson correlation. Results: Interleukin-19 (IL-19) and Osteopontin (OPN) showed significantly lower levels post exercise, whereas APRIL/TNFSF13, sCD30/TNFRSF8, MMP-3, sTNFR1, and TSLP showed significantly higher levels after exercise compared with levels before exercise. Cytokines that showed an association with VO2max, peak power output, body fat percentage and body temperature at baseline were BAFF/TNFSF13B, MMP-2, Pentraxin-3, IFNa2, IL-29 and Osteocalcin. Conclusion: It is concluded that acute strenuous exercise change both pro-inflammatory and antiinflammatory cytokines levels, but it remains to be investigated for how long these changes are sustained, or modified by regular exercise training.

  • 43.
    Aichernig, Bernhard K.
    et al.
    Graz University of Technology, Graz, Austria.
    Mostowski, Wojciech
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES).
    Mousavi, Mohammad Reza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Centre for Research on Embedded Systems (CERES). Department of Informatics, University of Leicester, Leicester, UK.
    Tappler, Martin
    Graz University of Technology, Graz, Austria.
    Taromirad, Masoumeh
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Model Learning and Model-Based Testing2018In: Machine Learning for Dynamic Software Analysis: Potentials and Limits / [ed] Amel Bennaceur, Reiner Hähnle, Karl Meinke, Heidelberg: Springer, 2018, p. 74-100Conference paper (Refereed)
    Abstract [en]

    We present a survey of the recent research efforts in integrating model learning with model-based testing. We distinguished two strands of work in this domain, namely test-based learning (also called test-based modeling) and learning-based testing. We classify the results in terms of their underlying models, their test purpose and techniques, and their target domains. © Springer International Publishing AG

  • 44.
    Aires, Nibia
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    A guide to the Fortran programs to calculate inclusion probabilities for conditional Poisson sampling and Pareto pi ps sampling designs2004In: Computational statistics (Zeitschrift), ISSN 0943-4062, E-ISSN 1613-9658, Vol. 19, no 3, p. 337-345Article in journal (Refereed)
    Abstract [en]

    Conditional Poisson Sampling and Pareto pips Sampling designs are sampling methods with fixed sample size and with inclusion probabilities proportional to given size measures.. Algorithms were introduced to calculate first and second exact inclusion probabilities for both schemes. Methods were also provided to adjust the parameters to get predetermined inclusion probabilities. In this paper, the Fortran procedures are introduced and documented. Moreover, guidelines are provided for their use as well as examples and the programs codes commented.

  • 45.
    Akram, Asif
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Value Creation in Digital Ecosystem – A Study of Remote Diagnostics2013Conference paper (Refereed)
    Abstract [en]

    The advancement of digital technologies is driving traditional product oriented businesses to move from selling product to selling solutions. In order to exploit business potentials from technology, it is necessary to understand the technological capacity and how it influences the value creation in the environment where it is deployed. I study remote diagnostics as an example of digital technology within the vehicle industry. I found that this technology provides potential to generate new value. To create this value, traditional product oriented organizations are required to create value in different way than traditional mode of creating value. In this paper, I show that how generative capacity of remote diagnostics technology creates value in digital ecosystem.

  • 46.
    Akram, Asif
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab). University of Gothenburg, Gothenburg, Sweden.
    Value Network Transformation: Digital Service Innovation in the Vehicle Industry2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Advancement in digital technology is rapidly changing the contemporary landscape of business and associated networks for manufacturing firms. Many traditional physical products are now being embedded with digital components, providing them digital capability to become digitized products. The digitization of physical products has become an important driver for digital service innovation within manufacturing industries. Such digital service innovation transforms value networks of manufacturing firms in various industries. While digitization of products and digital service innovation can be observed in many manufacturing industries, this thesis focuses on the transformation of value networks within the vehicle industry.

    This thesis is a collection of papers and a cover paper. The thesis reports from a collaborative project in the vehicle industry. The project explored new digital services for vehicles based on remote diagnostics technology. The exploration and conceptualization of digital services is investigated in a collaborative manner with participants from the vehicle industry. The results reflect that there is a paradigm shift for manufacturing firms digitizing their products, and stretching the business scope from product to solution oriented business.

    This thesis contributes to the existing literature on digital innovation with insights on the transformation of value networks in the vehicle industry. The research question addressed in this thesis is: How are value networks of manufacturing firms transformed by digital service innovation? To answer the question, this thesis conceptualizes how the value creating pattern of digitized products transforms value networks of manufacturing firms. A model is presented that reflects how the symbiotic value relationship between the digitized product and digital services transforms the roles, relationships and exchanges in the value networks of manufacturing firms. The model can serve as an analytical tool to further advance the knowledge on business aspects in digital innovation. This thesis contributes to practice by providing an understanding of how manufacturing firms can leverage value of digitized products and digital services in value networks.

  • 47.
    Akram, Asif
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Bergquist, Magnus
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). University of Gothenburg.
    Åkesson, Maria
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Digital Visions vs. Product Practices: Understanding Tensions in Incumbent Manufacturing Firms2014In: Proceedings of the Annual Hawaii International Conference on System Sciences / [ed] Ralph H. Sprague, Jr., Los Alamitos, CA: IEEE Computer Society, 2014, p. 4516-4525Conference paper (Refereed)
    Abstract [en]

    Incumbent manufacturing firms face challenges when expanding their product focus with digital services. Such expansion creates tensions in organizations in the servitization process. While management visions and conceptualizes new service oriented businesses, the actual practice of implementing these service concepts is influenced by the product paradigmatic way of thinking in the organization. This dominant thinking creates tensions between business visions and business practice. We use the case of remote diagnostics services to provide insights into a manufacturing firm’s attempt to transform the dominant oriented business models into a new networked environment. We suggest that such acts that may or may not lead to transition are lingered by dominant logics related to the product focus. This indicates that firms are required to embed new logics into their existing practice in order to exploit the full potential of digital technology. © 2014 IEEE.

  • 48.
    Akram, Asif
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Åkesson, Maria
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), Man and Information technology laboratory (MI-lab).
    Value Network Transformation By Digital Service Innovation In The Vehicle Industry2011In: Proceedings of the 15th Pacific Asia Conference on Information Systems | Pacific Asia Conference on Information Systems (PACIS), Brisbane, Australia: Association for Information Systems, 2011Conference paper (Other academic)
    Abstract [en]

    This paper reports from preparations in an ongoing research study concerning how digital service innovation transforms value networks in the vehicle industry. The research study concerns digital services based on remote diagnostics systems. This digital service innovation in particular is of great importance since the vehicle industry has great potential to expand its business and found new and extended boundaries and relationships with other stakeholder in the networks they are attached to. Core challenges and opportunities for digital service innovation will lead us to the study of its influence on the business and innovation environment i.e. the value network. In this paper, we propose three propositions to study transformation from product oriented value networks to digital service oriented value networks.

  • 49.
    Akujor, Chidi E.
    et al.
    Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
    Bååth, L.B.
    Onsala Space Observatory, Chalmers University of Technology, Gothenburg, Sweden.
    Combined-Array Imaging of Extra-Galactic Radio Sources1994In: Astronomy with Millimeter and Submillimeter Wave Interferometry: IAU Colloquium 140 : Meeting held 5-9 October 1992, Hakone, Japan / [ed] M. Ishiguro & Wm. J. Welch, San Francisco: Astronomical Society of the Pacific , 1994, p. 123-124Conference paper (Refereed)
  • 50.
    Akula, Viswa Raj
    Halmstad University, School of Business and Engineering (SET).
    Wetland biomass - suitable for biogas production?2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wetlands have long been used as natural waste water treatment systems to remove excess nutrients from agriculture or other waste waters. Common reed (Phragmites australis) is the most prominent feature of wetlands in Sweden. This wetland vegetation needs to be harvested and can be used as substrate for biofuel production. In this study, common reed and submerged vegetation from two wetlands outside Halmstad have been harvested in August and October and have been used as substrate for anaerobic digestion in a laboratory experiment. August harvested common reed produced on average 147 ml CH4/g VS, October harvested common reed produced 150 ml CH4/g VS while August harvested free floating vegetation produced 130 ml CH4/g VS. Similar methane production was seen from reed harvested in August and reed harvested in October, but the dry weight of October harvested reed is much higher indicating that harvesting in October can be beneficial not only because of more biogas production but also because a late harvest reduces the amount of biomass to be harvested and transported. Apart from that harvesting in October will not affect the migratory birds which use wetlands as resting place during autumn migration. 

1234567 1 - 50 of 1910
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf