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  • 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.

    Download full text (pdf)
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  • 2.
    Abiri, Najmeh
    et al.
    Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden.
    Linse, Björn
    Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden.
    Edén, Patrik
    Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden.
    Ohlsson, Mattias
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research. Department of Astronomy and Theoretical Physics, Lund University, Lund, Sweden.
    Establishing strong imputation performance of a denoising autoencoder in a wide range of missing data problems2019In: Neurocomputing, ISSN 0925-2312, E-ISSN 1872-8286, Vol. 65, p. 137-146Article in journal (Refereed)
    Abstract [en]

    Dealing with missing data in data analysis is inevitable. Although powerful imputation methods that address this problem exist, there is still much room for improvement. In this study, we examined single imputation based on deep autoencoders, motivated by the apparent success of deep learning to efficiently extract useful dataset features. We have developed a consistent framework for both training and imputation. Moreover, we benchmarked the results against state-of-the-art imputation methods on different data sizes and characteristics. The work was not limited to the one-type variable dataset; we also imputed missing data with multi-type variables, e.g., a combination of binary, categorical, and continuous attributes. To evaluate the imputation methods, we randomly corrupted the complete data, with varying degrees of corruption, and then compared the imputed and original values. In all experiments, the developed autoencoder obtained the smallest error for all ranges of initial data corruption. © 2019 Elsevier B.V.

  • 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.

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  • 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.
    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

  • 21.
    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.

  • 22.
    Afram, Abboud
    et al.
    Halmstad University, School of Information Technology.
    Sarab Fard Sabet, Danial
    Halmstad University, School of Information Technology.
    Exploring State-of-the-Art Machine Learning Methods for Quantifying Exercise-induced Muscle Fatigue2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Muscle fatigue is a severe problem for elite athletes, and this is due

    to the long resting times, which can vary. Various mechanisms can

    cause muscle fatigue which signifies that the specific muscle has

    reached its maximum force and cannot continue the task. This thesis

    was about surveying and exploring state-of-the-art methods and

    systematically, theoretically, and practically testing the applicability

    and performance of more recent machine learning methods on an existing

    EMG to muscle fatigue pipeline. Several challenges within the

    EMG domain exist, such as inadequate data, finding the most suitable

    model, and how they should be addressed to achieve reliable

    prediction. This required approaches for addressing these problems

    by combining and comparing various state-of-the-art methodologies,

    such as data augmentation techniques for upsampling, spectrogram

    methods for signal processing, and transfer learning to gain a reliable

    prediction by various pre-trained CNN models.

    The approach during this study was to conduct seven experiments

    consisting of a classification task that aims to predict muscle fatigue

    in various stages. These stages are divided into 7 classes from 0-6, and

    higher classes represent a fatigued muscle. In the tabular part of the

    experiments, the Decision Tree, Random Forest, and Support Vector

    Machine (SVM) were trained, and the accuracy was determined. A

    similar approach was made for the spectrogram part, where the signals

    were converted to spectrogram images, and with a combination

    of traditional- and intelligent data augmentation techniques, such as

    noise and DCGAN, the limited dataset was increased. A comparison

    between the performance of AlexNet, VGG16, DenseNet, and InceptionV3

    pre-trained CNN models was made to predict differences in

    jump heights.

    The result was evaluated by implementing baseline classifiers on

    tabular data and pre-trained CNN model classifiers for CWT and

    STFT spectrograms with and without data augmentation. The evaluation

    of various state-of-the-art methodologies for a classification

    problem showed that DenseNet and VGG16 gave a reliable accuracy

    of 89.8 % on intelligent data augmented CWT images.

    The intelligent data augmentation applied on CWT images allows

    the pre-trained CNN models to learn features that can generalize unseen

    data. Proving that the combination of state-of-the-art methods

    can be introduced and address the challenges within the EMG domain.

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  • 23.
    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.

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  • 24.
    Agelis, Sacki
    Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Reconfigurable Optical Interconnection Networks for High-Performance Embedded2005Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In embedded computer and communication system the capacity demand for interconnection networks is increasing continuously in order to achieve high-performance systems. Recent breakthroughs show that by using reconfigurability inside a single chip substantial performance gains can be added. However, in this thesis the focus is on system level reconfigurability (between chips or modules) and the performance gains that potentially can be achieved by having support for runtime reconfigurability on the system level.This thesis addresses the field of runtime system level reconfigurability with the use of optics in switches and routers for data- and telecommunications, and in multi-processor systems used for embedded signal processing. Several reconfigurable systems for switching and routing with support to adapt for asymmetric traffic patterns are proposed and compared to identify how design choices affect flexibility, performance etc. The proposed solutions are characterized by their multistage optical interconnection networks with reconfigurable shuffle patterns, where the reconfigurability is provided by micro-optical-electrical mechanical systems. More specifically, application-specific bottlenecks can be resolved by reconfiguring the interconnection network according to the current application demands. The benefits of the architectural solutions are confirmed by simulations that clearly show that the architectures can achieve high performance for both symmetric application characteristics and for several classes of asymmetric application characteristics. The final architectural solution is characterized by electronic packet-switches interconnected through an optical backplane, which is reconfigurable. Moreover, the thesis presents how several signal processing applications can be mapped to run concurrently in a time-shared scheme on a single reconfigurable multi-processor system that has high flexibility to adapt for the application currently at hand. The interconnection network is then adapted (reconfigured) according to the demands of the currently executed application in each time instance. The analysis shows that it is feasible to build such a system with today’s components.

  • 25.
    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.

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  • 26.
    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.

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  • 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 MOEMS–based reconfigurable shuffle network2004Conference paper (Refereed)
  • 28.
    Ahl, Josefin
    et al.
    Halmstad University, School of Information Technology.
    Djurklou, Julia
    Halmstad University, School of Information Technology.
    Ransomware-hotet mot svenska sjukhus: – en intervju- och litteraturstudie2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Statistics show an increase in ransomware activity in recent years. The increase is mainly due to the ongoing Covid-19 pandemic. Cybercriminals take advantage of the fact that hospitals worldwide are overloaded with caring for seriously ill patients in Covid-19 and perform ransomware attacks.

    This thesis examines how Swedish hospitals experience and handle the increased threat of ransomware. The bachelor’s thesis consists of a literature study and some in-depth interviews. The literature study is investigating ransomware as a phenomenon and finding out why it is a successful method for cybercriminals to use in digital extortion.

    The purpose is also to investigate how Swedish hospitals relate to the fact that the healthcare sector has become an attractive target for cyber-attacks. The interview study examines the hospitals' IT security to determine whether they are sufficiently resistant to ransomware attacks. The interview results are discussed and analyzed against the background of the literature. The conclusion of this analysis is the basis for the proposed countermeasure.

    The results show that the hospitals surveyed have suitable IT security. The most central security mechanisms for the hospitals are their backup and recovery routines in the fight against ransomware. The discussion in this work combines the results from the literature and interview studies carried out. Based on the discussion, the conclusion is that the hospitals surveyed have good security and meet most of the recommendations published by Swedish authorities. Still, there is room for some improvement which is indicated.

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  • 29.
    Ahlman, Adam
    et al.
    Halmstad University, School of Information Technology.
    Taylor, Adam
    Halmstad University, School of Information Technology.
    Dataset characteristics effect on time series forecasting: comparison of statistical and deep learning models2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Time series are points of data measured throughout time in equally spaced periods. They present characteristics such as level, noise, trend, seasonality, and outliers. Time series forecasting is the attempt to predict single or multiple future values. It holds significant relevance in numerous fields,including, but not limited to, healthcare, finance, and weather forecasting. It has recently gained more attention due to the COVID-19 pandemic, which highlighted the importance of predicting and managing crises. Two distinct methods of forecasting utilise either statistical or deep learning models, and the debate about the best model is still inconclusive. This thesis aimed to explicate the benefits and drawbacks of each approach pertaining to singlestep and multi-step forecasting. The study applied four models, two of each method, on datasets of varying characteristics and measured their prediction accuracy and computing time. The prediction accuracy of each model was measured using commonly used evaluation metrics, including Root MeanSquare Error. Subsequently, the results were compared with the features of the datasets to identify possible interconnecting relations between the factors. The findings concluded that the deep learning models generally produced a more accurate prediction but required more processing power and computing time. Contrastingly, the statistical models' predictions were less accurate butmarginally faster. Furthermore, the forecast accuracy's most impactful characteristics were the dataset's trend and linearity. The code and datasets were published at: https://github.com/Adam20Taylor/BScThesis

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  • 30.
    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.

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  • 31.
    Ahlstrand, Roland
    Halmstad University, School of Business and Engineering (SET), Centre for Innovation, Entrepreneurship and Learning Research (CIEL), Regional Learning and Governance (RELL).
    Social responsibility in connection with business closures: A study of closures of Ericsson Telecom facilities in Norrköping and Linköping2010In: Economic and Industrial Democracy, ISSN 0143-831X, E-ISSN 1461-7099, Vol. 31, no 4, p. 537-555Article in journal (Refereed)
    Abstract [en]

    The present article analyses why and how Ericsson Telecom assumeda greater responsibility than was legally required when it dismissedmore than 23,000 employees in Sweden at the beginning of the21st century. The analysis starts from neoinstitutional theoryand is based on case studies of the company’s closuresin Norrköping and Linköping. The article focuses,in particular, on the interaction between Ericsson, the tradeunions, the County Administrative Board, the County Labour Board,the Public Employment Service, the Swedish Employment SecurityCouncil, the government and the respective municipalities. Itis shown that the greater responsibility taken by Ericsson wasbased on its desire to maintain legitimacy by taking into considerationprevailing societal expectations regarding the company’sbehaviour.

  • 32.
    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.

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  • 33.
    Ahmadi, Asghar
    et al.
    Australian Catholic University, North Sydney, NSW, Australia.
    Noetel, Michael
    Australian Catholic University, North Sydney, NSW, Australia.
    Schellekens, Melissa
    Australian Catholic University, North Sydney, NSW, Australia.
    Parker, Philip
    Australian Catholic University, North Sydney, NSW, Australia.
    Antczak, Devan
    Australian Catholic University, North Sydney, NSW, Australia.
    Beauchamp, Mark
    The University of British Columbia, Vancouver, Canada.
    Dicke, Theresa
    Australian Catholic University, North Sydney, NSW, Australia.
    Diezmann, Carmel
    Queensland University of Technology, Brisbane, Australia.
    Maeder, Anthony
    Flinders University, Adelaide, Australia.
    Ntoumanis, Nikos
    Halmstad University, School of Health and Welfare. Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark; School of Psychology, Curtin University, Perth, Australia.
    Yeung, Alexander
    Australian Catholic University, North Sydney, NSW, Australia.
    Lonsdale, Chris
    Australian Catholic University, North Sydney, NSW, Australia.
    A Systematic Review of Machine Learning for Assessment and Feedback of Treatment Fidelity2021In: Psychosocial Intervention, ISSN 1132-0559, E-ISSN 2173-4712, Vol. 30, no 3, p. 139-153Article, review/survey (Refereed)
    Abstract [en]

    Many psychological treatments have been shown to be cost-effective and efficacious, as long as they are implemented faithfully. Assessing fidelity and providing feedback is expensive and time-consuming. Machine learning has been used to assess treatment fidelity, but the reliability and generalisability is unclear. We collated and critiqued all implementations of machine learning to assess the verbal behaviour of all helping professionals, with particular emphasis on treatment fidelity for therapists. We conducted searches using nine electronic databases for automated approaches of coding verbal behaviour in therapy and similar contexts. We completed screening, extraction, and quality assessment in duplicate. Fifty-two studies met our inclusion criteria (65.3% in psychotherapy). Automated coding methods performed better than chance, and some methods showed near human-level performance; performance tended to be better with larger data sets, a smaller number of codes, conceptually simple codes, and when predicting session-level ratings than utterance-level ones. Few studies adhered to best-practice machine learning guidelines. Machine learning demonstrated promising results, particularly where there are large, annotated datasets and a modest number of concrete features to code. These methods are novel, cost-effective, scalable ways of assessing fidelity and providing therapists with individualised, prompt, and objective feedback. © 2021 Colegio Oficial de la Psicología de Madrid

  • 34.
    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.

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  • 35.
    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

  • 36.
    Ailm, Kajsa
    et al.
    Halmstad University.
    Lindroos, Max
    Halmstad University.
    Vilka utmaningar finns för design av socialt användarengagemang på digitala spelplattformar?2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study aims to investigate social user engagement on digital gaming platforms through the research question: What challenges are there when designing for social engagement on digital gaming platforms? Social user engagement means that user's engagement between each other is facilitated through functions on the digital platform such as Facebook and Twitter. Previous research on user engagement on digital gaming platforms has tried to create user engagement through new social functions. However, there are problems for designers of digital gaming platforms because users choose to interact and communicate on other digital social platforms. The fact that users choose to communicate on other digital platforms than on digital gaming platforms may be linked to the fact that users of digital gaming platforms have a different purpose and need with their interaction. It is therefore important when designing digital gaming platforms to have new functions as an extension of the digital gaming platform's basic functions and that user's game-related goals are prioritized. The study was based on a design-oriented research approach where three design elements have been implemented and evaluated through a probe. The study resulted in four design challenges that are intended to target designers of digital gaming platforms as a support for the development of digital gaming platforms. The identified design challenges are recommended to be considered to improve user's experience on digital gaming platforms.

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  • 37.
    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.

  • 38.
    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.

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  • 39.
    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.

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  • 40.
    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.

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  • 41.
    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.

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  • 42.
    Al Khatib, Sultan M.
    et al.
    Al-balqa Applied University, Al Salt, Jordan.
    Alkharabsheh, Khalid
    Al-balqa Applied University, Al Salt, Jordan.
    Alawadi, Sadi
    Halmstad University, School of Information Technology. Uppsala University, Uppsala, Sweden.
    Selection of human evaluators for design smell detection using dragonfly optimization algorithm: An empirical study2023In: Information and Software Technology, ISSN 0950-5849, E-ISSN 1873-6025, Vol. 155, article id 107120Article in journal (Refereed)
    Abstract [en]

    Context: Design smell detection is considered an efficient activity that decreases maintainability expenses and improves software quality. Human context plays an essential role in this domain. Objective: In this paper, we propose a search-based approach to optimize the selection of human evaluators for design smell detection. Method: For this purpose, Dragonfly Algorithm (DA) is employed to identify the optimal or near-optimal human evaluator's profiles. An online survey is designed and asks the evaluators to evaluate a sample of classes for the presence of god class design smell. The Kappa-Fleiss test has been used to validate the proposed approach. Results: The results show that the dragonfly optimization algorithm can be utilized effectively to decrease the efforts (time, cost ) of design smell detection concerning the identification of the number and the optimal or near-optimal profile of human experts required for the evaluation process. Conclusions: A Search-based approach can be effectively used for improving a god-class design smell detection. Consequently, this leads to minimizing the maintenance cost. © 2022 The Author(s)

  • 43.
    Alabdallah, Abdallah
    et al.
    Halmstad University, School of Information Technology.
    Jakubowski, Jakub
    Pashami, Sepideh
    Halmstad University, School of Information Technology.
    Bobek, Szymon
    Ohlsson, Mattias
    Halmstad University, School of Information Technology.
    Rögnvaldsson, Thorsteinn
    Halmstad University, School of Information Technology.
    Nalepa, Grzegorz J.
    Understanding Survival Models through Counterfactual ExplanationsManuscript (preprint) (Other academic)
    Abstract [en]

    The development of black-box survival models has created a need for methods that explain their outputs, just as in the case of traditional machine learning methods. Survival models usually predict functions rather than point estimates. This special nature of their output makes it more difficult to explain their operation. We propose a method to generate plausible counterfactual explanations for survival models. The method supports two options that handle the special nature of survival models' output. One option relies on the Survival Scores, which are based on the area under the survival function, which is more suitable for proportional hazard models. The other one relies on Survival Patterns in the predictions of the survival model, which represent groups that are significantly different from the survival perspective. This guarantees an intuitive well-defined change from one risk group (Survival Pattern) to another and can handle more realistic cases where the proportional hazard assumption does not hold. The method uses a Particle Swarm Optimization algorithm to optimize a loss function to achieve four objectives: the desired change in the target, proximity to the explained example, likelihood, and the actionability of the counterfactual example. Two predictive maintenance datasets and one medical dataset are used to illustrate the results in different settings. The results show that our method produces plausible counterfactuals, which increase the understanding of black-box survival models.

  • 44.
    Alabdallah, Abdallah
    et al.
    Halmstad University, School of Information Technology.
    Ohlsson, Mattias
    Halmstad University, School of Information Technology. Lund University, Lund, Sweden.
    Pashami, Sepideh
    Halmstad University, School of Information Technology. RISE Research Institutes of Sweden, Stockholm, Sweden.
    Rögnvaldsson, Thorsteinn
    Halmstad University, School of Information Technology.
    The Concordance Index Decomposition: A Measure for a Deeper Understanding of Survival Prediction Models2024In: Artificial Intelligence in Medicine, ISSN 0933-3657, E-ISSN 1873-2860, Vol. 148, p. 1-10, article id 102781Article in journal (Refereed)
    Abstract [en]

    The Concordance Index (C-index) is a commonly used metric in Survival Analysis for evaluating the performance of a prediction model. This paper proposes a decomposition of the C-index into a weighted harmonic mean of two quantities: one for ranking observed events versus other observed events, and the other for ranking observed events versus censored cases. This decomposition enables a more fine-grained analysis of the strengths and weaknesses of survival prediction methods. The usefulness of this decomposition is demonstrated through benchmark comparisons against state-of-the-art and classical models, together with a new variational generative neural-network-based method (SurVED), which is also proposed in this paper. Performance is assessed using four publicly available datasets with varying levels of censoring. The analysis using the C-index decomposition and synthetic censoring shows that deep learning models utilize the observed events more effectively than other models, allowing them to keep a stable C-index in different censoring levels. In contrast, classical machine learning models deteriorate when the censoring level decreases due to their inability to improve on ranking the events versus other events. © 2024 The Author(s)

  • 45.
    Alabdallah, Abdallah
    et al.
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Pashami, Sepideh
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR). RISE Research Institutes of Sweden.
    Rögnvaldsson, Thorsteinn
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Ohlsson, Mattias
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR). Lund University, Lund, Sweden.
    SurvSHAP: A Proxy-Based Algorithm for Explaining Survival Models with SHAP2022In: 2022 IEEE 9th International Conference on Data Science and Advanced Analytics (DSAA) / [ed] Joshua Zhexue Huang; Yi Pan; Barbara Hammer; Muhammad Khurram Khan; Xing Xie; Laizhong Cui; Yulin He, Piscataway, NJ: IEEE, 2022Conference paper (Refereed)
    Abstract [en]

    Survival Analysis models usually output functions (survival or hazard functions) rather than point predictions like regression and classification models. This makes the explanations of such models a challenging task, especially using the Shapley values. We propose SurvSHAP, a new model-agnostic algorithm to explain survival models that predict survival curves. The algorithm is based on discovering patterns in the predicted survival curves, the output of the survival model, that would identify significantly different survival behaviors, and utilizing a proxy model and SHAP method to explain these distinct survival behaviors. Experiments on synthetic and real datasets demonstrate that the SurvSHAP is able to capture the underlying factors of the survival patterns. Moreover, SurvSHAP results on the Cox Proportional Hazard model are compared with the weights of the model to show that we provide faithful overall explanations, with more fine-grained explanations of the sub-populations. We also illustrate the wrong model and explanations learned by a Cox model when applied to heterogeneous sub-populations. We show that a non-linear machine learning survival model with SurvSHAP can better model the data and provide better explanations than linear models.

  • 46.
    Alabdallah, Abdallah
    et al.
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Rögnvaldsson, Thorsteinn
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Fan, Yuantao
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Pashami, Sepideh
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Ohlsson, Mattias
    Halmstad University, School of Information Technology, Center for Applied Intelligent Systems Research (CAISR).
    Discovering Premature Replacements in Predictive Maintenance Time-to-Event Data2023In: Proceedings of the Asia Pacific Conference of the PHM Society 2023 / [ed] Takehisa Yairi; Samir Khan; Seiji Tsutsumi, New York: The Prognostics and Health Management Society , 2023, Vol. 4Conference paper (Refereed)
    Abstract [en]

    Time-To-Event (TTE) modeling using survival analysis in industrial settings faces the challenge of premature replacements of machine components, which leads to bias and errors in survival prediction. Typically, TTE survival data contains information about components and if they had failed or not up to a certain time. For failed components, the time is noted, and a failure is referred to as an event. A component that has not failed is denoted as censored. In industrial settings, in contrast to medical settings, there can be considerable uncertainty in an event; a component can be replaced before it fails to prevent operation stops or because maintenance staff believe that the component is faulty. This shows up as “no fault found” in warranty studies, where a significant proportion of replaced components may appear fault-free when tested or inspected after replacement.

    In this work, we propose an expectation-maximization-like method for discovering such premature replacements in survival data. The method is a two-phase iterative algorithm employing a genetic algorithm in the maximization phase to learn better event assignments on a validation set. The learned labels through iterations are accumulated and averaged to be used to initialize the following expectation phase. The assumption is that the more often the event is selected, the more likely it is to be an actual failure and not a “no fault found”.

    Experiments on synthesized and simulated data show that the proposed method can correctly detect a significant percentage of premature replacement cases.

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  • 47.
    Alasjö, Alexander
    Halmstad University, School of Information Technology.
    Sidokanalattack mot knappsats för elektroniskt passersystem2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Through an exploratory experiment using electromagnetic side-channel attack against a keypad for a commercial entry system it is demonstrated that information leakage through side-channels are an ongoing issue and may make entry systems vulnerable by recording of user data.

    Using simple radio equipment, keypresses can be recorded and decoded by undesired electromagnetic radiation and theoretically it is possible to carry out the attack on a longer distance with a specially designed antenna and a custom recieiver.

    The report discusses emission security in consumer products which in military context is termed Tempest or compromising emanations (Swedish: RÖS) and requires expensive tests to be detected and handled.

    The EMC regulations (electromagnetic compatibility) handles radiation and influence of electromagnetic waves in electronic apparatus and nets, but not directly how information can leak from information technology equipment which this report wants to problematize.

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  • 48.
    Al-bashki, Abraham
    et al.
    Halmstad University, School of Information Technology.
    Oogle, Ahmed
    Halmstad University, School of Information Technology.
    Math Visualizations in VR2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Visualization of linear algebra with virtual reality (VR) can be helpful for math teachers. A study has shown more engagement, focus, and active learning through immersion and interactivity, supplementing opportunities for visualizing abstract concepts. This project aims to provide math teachers with an accessible tool for linear algebra concepts in VR. The focus will be on abstraction for the coding by providing a graphical user interface (GUI) as a middle ground, premade virtual objects to reuse, and a manual with linear algebra examples. Furthermore, there are several math visualization tools available for VR. However, there is currently no information about a tool made specifically for math teachers focusing on linear algebra to prepare lessons for VR environments. Unity is the preferred game engine for this project. The object-oriented design used in this project is polymorphism, Model-View-Controller (MVC), and the commandpattern. The system development methodology is extreme programming (XP). The system development methodology is extreme programming (XP). Unit tests are used to drive development; integration tests are used to test between classes; paired t-testis used to test the student’s learning with the tool and, additionally, test the experience of using the tool with a usability test. Furthermore, integration tests, usability tests, and paired t-test are used to analysis the result. Moreover, the linear algebra objects is created as data models. A controller uses linear algebra objects to update the GUI and the handles for visual manipulation. Undoing and saving are handled in the controller. Two simple linear algebra lessons are created by two teachers. The student access the saved lessons in VR and uses handles to interact with the VR world. Moreover,linear algebra expressions of the objects manipulated are shown to the student. Thetest results showed positive results.This framework can assist in empowering the creation of three-dimensional (3D) worlds and VR experiences, making them more accessible to a wider variety of educators by removing the requirement that teachers possess coding abilities. As aconcept, it can be promising for math teachers to have control over the design of their own VR world without caring about the data science behind it.

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  • 49.
    Albinsson, John
    et al.
    Lund Univ, Dept Biomed Engn, S-22100 Lund, Sweden..
    Brorsson, Sofia
    Halmstad University, School of Business, Engineering and Science, The Rydberg Laboratory for Applied Sciences (RLAS).
    Rydén Ahlgren, Åsa
    Lund Univ, Dept Clin Sci, Clin Physiol & Nucl Med Unit, Malmo, Sweden..
    Cinthio, Magnus
    Lund Univ, Dept Biomed Engn, S-22100 Lund, Sweden..
    Improved tracking performance of lagrangian block-matching methodologies using block expansion in the time domain: In silico, phantom and invivo evaluations2014In: Ultrasound in Medicine and Biology, ISSN 0301-5629, E-ISSN 1879-291X, Vol. 40, no 10, p. 2508-2520Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to evaluate tracking performance when an extra reference block is added to a basic block-matching method, where the two reference blocks originate from two consecutive ultrasound frames. The use of an extra reference block was evaluated for two putative benefits: (i) an increase in tracking performance while maintaining the size of the reference blocks, evaluated using in silico and phantom cine loops; (ii) a reduction in the size of the reference blocks while maintaining the tracking performance, evaluated using in vivo cine loops of the common carotid artery where the longitudinal movement of the wall was estimated. The results indicated that tracking accuracy improved (mean - 48%, p<0.005 [in silico]; mean - 43%, p<0.01 [phantom]), and there was a reduction in size of the reference blocks while maintaining tracking performance (mean - 19%, p<0.01 [in vivo]). This novel method will facilitate further exploration of the longitudinal movement of the arterial wall. (C) 2014 World Federation for Ultrasound in Medicine & Biology.

  • 50.
    Aldén, Victoria
    et al.
    Halmstad University, School of Information Technology.
    Gunnarsson, Ebba
    Halmstad University, School of Information Technology.
    Användningen av Robotic Process Automation i kommunala förvaltningars beslutsstödsprocesser: En studie om vilka konsekvenser som kan uppstå genom användningen av RPA och påverkan på kommunala beslutsstödsprocesser för försörjningsstöd2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In communal organizations there has previously not existed a law that allowed automated decision support, it was during the year 2018 that the law changed. Previous research has focused on automation in the private business sector, which has created a lack of research on public organizations. Following the change in the law, Social services have started to automate the decision support in their decision support processes. The automation takes place using the software technology RPA (Robot Process Automation). RPA can only handle processes that are regulated and structured. It forces the Social services to define and structure their decision support processes that were previously manually performed by administrators. It involves creation of consequences that affects the decision support process and leads to the study ́s question: How is the decision support process in communal organizations affected using RPA? A qualitative method has been used in the collection of literature and empirical data, in order to be able to identify the consequences and its impact in the decision support process. The identified consequences presented in the study's conclusion are divided into the categories: consequences based on RPA and consequences based on the administrators. The consequences identified in the study have differed between the communal organizations, depending on how they interpreted the law and whether RPA has started to be used in the communes yet.

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