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  • 1.
    Abbas, Muhammad Tahir
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Eklund, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Alfredsson, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Caso, Giuseppe
    Ericsson Research, Sweden.
    Kousias, Konstantinos
    Simula Research Laboratory, Norway.
    Alay, Özgü
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). University of Oslo, Norway.
    Energy-Saving Solutions for Cellular Internet of Things - A Survey2022In: IEEE Access, E-ISSN 2169-3536, Vol. 10, p. 62096-62096Article in journal (Refereed)
    Abstract [en]

    The Cellular Internet of Things (CIoT), a new paradigm, paves the way for a large-scale deployment of IoT devices. CIoT promises enhanced coverage and massive deployment of low-cost IoT devices with an expected battery life of up to 10 years. However, such a long battery life can only be achieved provided the CIoT device is configured with energy efficiency in mind. This paper conducts a comprehensive survey on energy-saving solutions in 3GPP-based CIoT networks. In comparison to current studies, the contribution of this paper is the classification and an extensive analysis of existing energy-saving solutions for CIoT, e.g., the configuration of particular parameter values and software modifications of transport- or radio-layer protocols, while also stressing key parameters impacting the energy consumption such as the frequency of data reporting, discontinuous reception cycles (DRX), and Radio Resource Control (RRC) timers. In addition, we discuss shortcomings, limitations, and possible opportunities which can be investigated in the future to reduce the energy consumption of CIoT devices.

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  • 2.
    Ahmad, Muhammad Ovais
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    On the Efficiency of Supernodal Factorization in Interior-Point Method Using CPU-GPU Collaboration2020In: IEEE Access, E-ISSN 2169-3536, Vol. 8, p. 120892-120904Article in journal (Refereed)
    Abstract [en]

    Primal-dual interior-point method (PDIPM) is the most efficient technique for solving sparse linear programming (LP) problems. Despite its efficiency, PDIPM remains a compute-intensive algorithm. Fortunately, graphics processing units (GPUs) have the potential to meet this requirement. However, their peculiar architecture entails a positive relationship between problem density and speedup, conversely implying a limited affinity of GPUs for problem sparsity. To overcome this difficulty, the state-of-the-art hybrid (CPU-GPU) implementation of PDIPM exploits presence of supernodes in sparse matrices during factorization. Supernodes are groups of similar columns that can be treated as dense submatrices. Factorization method used in the state-of-the-art solver performs only selected operations related to large supernodes on GPU. This method is known to underutilize GPU’s computational power while increasing CPU-GPU communication overhead. These shortcomings encouraged us to adapt another factorization method, which processes sets of related supernodes on GPU, and introduce it to the PDIPM implementation of a popular open-source solver. Our adaptation enabled the factorization method to better mitigate the effects of round-off errors accumulated over multiple iterations of PDIPM. To augment performance gains, we also used an efficient CPU-based matrix multiplication method. When tested for a set of well-known sparse problems, the adapted solver showed average speed-ups of approximately 55X, 1.14X and 1.05X over the open-source solver’s original version, the state-of-the-art solver, and a highly optimized proprietary solver known as CPLEX, respectively. These results strongly indicate that our proposed hybrid approach can lead to significant performance gains for solving large sparse problems.

  • 3.
    Ahmed, Bestoun S.
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Bures, Miroslav
    Czech Technical University in Prague, Prague.
    Frajtak, Karel
    Czech Technical University in Prague, Prague.
    Cerny, Tomas
    Baylor University, Waco.
    Aspects of Quality in Internet of Things (IoT) Solutions: A Systematic Mapping Study2019In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 13758-13780Article in journal (Refereed)
    Abstract [en]

    Internet of Things (IoT) is an emerging technology that has the promising power to change our future. Due to the market pressure, IoT systems may be released without sufficient testing. However, it is no longer acceptable to release IoT systems to the market without assuring the quality. As in the case of new technologies, the quality assurance process is a challenging task. This paper shows the results of the first comprehensive and systematic mapping study to structure and categories the research evidence in the literature starting in 2009 when the early publication of IoT papers for IoT quality assurance appeared. The conducted research is based on the most recent guidelines on how to perform systematic mapping studies. A set of research questions is defined carefully regarding the quality aspects of the IoT. Based on these questions, a large number of evidence and research papers is considered in the study (478 papers). We have extracted and analyzed different levels of information from those considered papers. Also, we have classified the topics addressed in those papers into categories based on the quality aspects. The study results carry out different areas that require more work and investigation in the context of IoT quality assurance. The results of the study can help in a further understanding of the research gaps. Moreover, the results show a roadmap for future research directions.

  • 4.
    Ahmed, Bestoun S.
    et al.
    Czech Tech Univ, Fac Elect Engn, Dept Comp Sci, Software Testing Intelligent Lab, Prague 12135, Czech Republic. CZE.
    Zamli, Kamal Z.
    Univ Malaysia Pahang, Fac Comp Syst & Software Engn, Gambang 26300, Malaysia. MYS.
    Afzal, Wasif
    Malardalen Univ, Sch Innovat Design & Engn, S-72123 Vasteras, Sweden..
    Bures, Miroslav
    Czech Tech Univ, Fac Elect Engn, Dept Comp Sci, Software Testing Intelligent Lab, Prague 12135, Czech Republic. CZE.
    Constrained interaction testing: A systematic literature study2017In: IEEE Access, E-ISSN 2169-3536, Vol. 5, p. 25706-25730Article in journal (Refereed)
    Abstract [en]

    Interaction testing can be used to effectively detect faults that are otherwise difficult to find by other testing techniques. However, in practice, the input configurations of software systems are subjected to constraints, especially in the case of highly configurable systems. Handling constraints effectively and efficiently in combinatorial interaction testing is a challenging problem. Nevertheless, researchers have attacked this challenge through different techniques, and much progress has been achieved in the past decade. Thus, it is useful to reflect on the current achievements and shortcomings and to identify potential areas of improvements. This paper presents the first comprehensive and systematic literature study to structure and categorize the research contributions for constrained interaction testing. Following the guidelines of conducting a literature study, the relevant data are extracted from a set of 103 research papers belonging to constrained interaction testing. The topics addressed in constrained interaction testing research are classified into four categories of constraint test generation, application, generation and application, and model validation studies. The papers within each of these categories are extensively reviewed. Apart from answering several other research questions, this paper also discusses the applications of constrained interaction testing in several domains, such as software product lines, fault detection and characterization, test selection, security, and graphical user interface testing. This paper ends with a discussion of limitations, challenges, and future work in the area.

  • 5.
    Akil, Mahdi
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Islami, Lejla
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Martucci, Leonardo
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Zuccato, Albin
    ICA Gruppen AB.
    Privacy-Preserving Identifiers for IoT: A Systematic Literature Review2020In: IEEE Access, E-ISSN 2169-3536, Vol. 8, p. 168470-168485Article, review/survey (Refereed)
    Abstract [en]

    The Internet of Things (IoT) paves the way for smart applications such as in E-health, E-homes, transportation, or energy production. However, IoT technologies also pose privacy challenges for their users, as they allow the tracking and monitoring of the users' behavior and context. The EU General Data Protection Regulation (GDPR) mandates data controller to follow a data protection by design and default approach by implementing for instance pseudonymity for achieving data minimisation. This paper provides a systematic literature review for answering the question of what types of privacy-preserving identifiers are proposed by the literature in IoT environments for implementing pseudonymity. It contributes with classifications and analyses of IoT environments for which privacy-preserving identifiers have been proposed and of the pseudonym types and underlying identity management architectures used. Moreover, it discusses trends and gaps in regard to addressing privacy trade-offs.

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  • 6.
    Ali Shah, Usman
    et al.
    University of Engineering and Technology at Peshawar, Pakistan.
    Yousaf, Suhail
    University of Engineering and Technology at Peshawar, Pakistan.
    Ahmad, Iftikhar
    University of Engineering and Technology at Peshawar, Pakistan.
    Ur Rehman, Safi
    Karakoram International University, Pakistan.
    Ahmad, Muhammad Ovais
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Accelerating Revised Simplex Method using GPU-based Basis Update2020In: IEEE Access, E-ISSN 2169-3536, Vol. 8, p. 52121-52138Article in journal (Refereed)
    Abstract [en]

    Optimization problems lie at the core of scientific and engineering endeavors. Solutions to these problems are often compute-intensive. To fulfill their compute-resource requirements, graphics processing unit (GPU) technology is considered a great opportunity. To this end, we focus on linear programming (LP) problem solving on GPUs using revised simplex method (RSM). This method has potentially GPU-friendly tasks, when applied to large dense problems. Basis update (BU) is one such task, which is performed in every iteration to update a matrix called basis-inverse matrix. The contribution of this paper is two-fold. Firstly, we experimentally analyzed the performance of existing GPU-based BU techniques. We discovered that the performance of a relatively old technique, in which each GPU thread computed one element of the basis-inverse matrix, could be significantly improved by introducing a vectorcopy operation to its implementation with a sophisticated programming framework. Second, we extended the adapted element-wise technique to develop a new BU technique by using three inexpensive vector operations. This allowed us to reduce the number of floating-point operations and conditional processing performed by GPU threads. A comparison of BU techniques implemented in double precision showed that our proposed technique achieved 17.4% and 13.3% average speed-up over its closest competitor for randomly generated and well-known sets of problems, respectively. Furthermore, the new technique successfully updated basisinverse matrix in relatively large problems, which the competitor was unable to update. These results strongly indicate that our proposed BU technique is not only efficient for dense RSM implementations but is also scalable.

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  • 7.
    Caso, Giuseppe
    et al.
    Simula Metropolitan Center for Digital Engineering, NOR.
    Alay, Ozgu
    Simula Metropolitan Center for Digital Engineering, NOR.
    Ferrante, Guido Carlo
    Ericsson Research.
    De Nardis, Luca
    Sapienza University, ITA.
    Di Benedetto, Maria-Gabriella
    Sapienza University, ITA.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    User-Centric Radio Access Technology Selection: A Survey of Game Theory Models and Multi-Agent Learning Algorithms2021In: IEEE Access, E-ISSN 2169-3536, Vol. 9, p. 84417-84464Article in journal (Refereed)
    Abstract [en]

    User-centric radio access technology (RAT) selection is a key communication paradigm, given the increased number of available RATs and increased cognitive capabilities at the user end. When considered against traditional network-centric approaches, user-centric RAT selection results in reduced network-side management load, and leads to lower operational costs for RATs, as well as improved quality of service (QoS) and quality of experience (QoE) for users. The complex between-users interactions involved in RAT selection require, however, specific analyses, toward developing reliable and efficient schemes. Two theoretical frameworks are most often applied to user-centric RAT selection analysis, i.e., game theory (GT) and multi-agent learning (MAL). As a consequence, several GT models and MAL algorithms have been recently proposed to solve the problem at hand. A comprehensive discussion of such models and algorithms is, however, currently missing. Moreover, novel issues introduced by next-generation communication systems also need to be addressed. This paper proposes to fill the above gaps by providing a unified reference for both ongoing research and future research directions in the field. In particular, the review addresses the most common GT and MAL models and algorithms, and scenario settings adopted in user-centric RAT selection in terms of utility function and network topology. Regarding GT, the review focuses on non-cooperative models, because of their widespread use in RAT selection; as for MAL, a large number of algorithms are described, ranging from game-theoretic to reinforcement learning (RL) schemes, and also including most recent approaches, such as deep RL (DRL) and multi-armed bandit (MAB). Models and algorithms are analyzed by comparatively reviewing relevant literature. Finally, open challenges are discussed, in light of ongoing research and standardization activities.

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  • 8.
    Deng, Shuiguang
    et al.
    Zhejiang University, China..
    Xiang, Zhengzhe
    Zhejiang University, China..
    Yin, Jianwei
    Zhejiang University, China..
    Taheri, Javid
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Zomaya, Albert Y.
    University of Sydney, Australia..
    Composition-Driven IoT Service Provisioning in Distributed Edges2018In: IEEE Access, E-ISSN 2169-3536, Vol. 6, p. 54258-54269Article in journal (Refereed)
    Abstract [en]

    The increasing number of Internet of Thing (IoT) devices and services makes it convenient for people to sense the real world and makes optimal decisions or complete complex tasks with them. However, the latency brought by unstable wireless networks and computation failures caused by constrained resources limit the development of IoT. A popular approach to solve this problem is to establish an IoT service provision system based on a mobile edge computing (MEC) model. In the MEC model, plenty of edge servers are placed with access points via wireless networks. With the help of cached services on edge servers, the latency can be reduced, and the computation can be offloaded. The cache services must be carefully selected so that many requests can by satisfied without overloading resources in edge servers. This paper proposes an optimized service cache policy by taking advantage of the composability of services to improve the performance of service provision systems. We conduct a series of experiments to evaluate the performance of our approach. The result shows that our approach can improve the average response time of these IoT services.

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  • 9.
    Haile, Habtegebreil Kassaye
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Hurtig, Per
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    RBBR: A Receiver-driven BBR in QUIC for Low-latency in Cellular Networks2022In: IEEE Access, E-ISSN 2169-3536, Vol. 10, p. 18707-18719Article in journal (Refereed)
    Abstract [en]

    BBR is a promising new congestion control algorithm (CCA) that has been shown to result in significantly lower latency compared to conventional loss-based CCAs. However, in cellular networks, where there is a high variability in the available rate, BBR does not perform as well as expected. In such scenarios, BBR tends to overestimate the available capacity and create queues that cause longer packet delays. In this work, we propose Receiver-driven BBR (RBBR), a modified version of BBR that uses rate estimates made at the receiver side rather than at the sender side. We employ a Kalman filter to make a more accurate estimate of the available bandwidth, and we implement the algorithm in QUIC. An evaluation of the proposed CCA is done through extensive 4G trace-based emulations, real 4G network tests and mmWave trace-based emulations representing a 5G scenario. The results show that RBBR is able to achieve an RTT reduction of up to 80\% with a worst-case throughput loss of about 30\%. The results also show that in real 4G networks, RBBR flows experience a more predictable and consistent RTT than what BBR flows do.

  • 10.
    Iwaya, Leonardo H
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). The University of Adelaide, AUS; Cyber Security Cooperative Research Centre (CSCRC), AUS.
    Ahmad, Aakash
    University of Hail, SAU.
    Ali Babar, M.
    The University of Adelaide, AUS; Cyber Security Cooperative Research Centre (CSCRC), AUS.
    Security and Privacy for mHealth and uHealth Systems: A Systematic Mapping Study2020In: IEEE Access, E-ISSN 2169-3536, Vol. 8, p. 150081-150112Article in journal (Refereed)
    Abstract [en]

    An increased adoption of mobile health (mHealth) and ubiquitous health (uHealth) systems empower users with handheld devices and embedded sensors for a broad range of healthcare services. However, m/uHealth systems face significant challenges related to data security and privacy that must be addressed to increase the pervasiveness of such systems. This study aims to systematically identify, classify, compare, and evaluate state-of-the-art on security and privacy of m/uHealth systems. We conducted a systematic mapping study (SMS) based on 365 qualitatively selected studies to (i) classify the types, frequency, and demography of published research, (ii) synthesize and categorize research themes, (iii) recurring challenges, (iv) prominent solutions (i.e., research outcomes) and their (v) reported evaluations (i.e., practical validations). Results suggest that the existing research on security and privacy of m/uHealth systems primarily focuses on select group of control families (compliant with NIST800-53), protection of systems and information, access control, authentication, individual participation, and privacy authorisation. In contrast, areas of data governance, security and privacy policies, and program management are under-represented, although these are critical to most of the organizations that employ m/uHealth systems. Most research proposes new solutions with limited validation, reflecting a lack of evaluation of security and privacy of m/uHealth in the real world. Empirical research, development, and validation of m/uHealth security and privacy is still incipient, which may discourage practitioners from readily adopting solutions from the literature. This SMS facilitates knowledge transfer, enabling researchers and practitioners to engineer security and privacy for emerging and next generation of m/uHealth systems.

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  • 11.
    Iwaya, Leonardo H
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Federal University of Santa Catarina, Brazil.
    Iwaya, Gabriel Horn
    Federal University of Santa Catarina, Brazil.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Steil, Andrea Valeria
    Federal University of Santa Catarina, Brazil.
    Organisational Privacy Culture and Climate: A Scoping Review2022In: IEEE Access, E-ISSN 2169-3536, Vol. 10, p. 73907-73930Article, review/survey (Refereed)
    Abstract [en]

    New regulations worldwide are increasingly pressing organisations to review how they collect and process personal data to ensure the protection of individual privacy rights. This organisational transformation involves implementing several privacy practices (e.g., privacy policies, governance frameworks, and privacy-by-design methods) across multiple departments. The literature points to a strong influence of the organisations’ culture and climate in implementing such privacy practices, depending on how leaders and employees perceive and address privacy concerns. However, this new hybrid topic referred to as Organisational Privacy Culture and Climate (OPCC), remains poorly demarcated and weakly defined. In this paper, we report a Scoping Review (ScR) on the topic of OPCC to systematically identify and map studies, contributing with a synthesis of the existing work, distinguishing core and adjacent publications, research gaps, and pathways of future research. This ScR includes 36 studies categorised according to their demographics, research types, contribution types, research designs, proposed definitions, and conceptualisations. Also, 18 studies categorised as primary research were critically appraised, assessing the studies’ methodological quality and credibility of the evidence. Although published research has significantly advanced the topic of OPCC, more research is still needed. Our findings show that the topic is still in its embryonic stage. The theory behind OPCC has not yet been fully articulated, even though some definitions have been independently proposed. Only one measuring instrument for privacy culture was identified, but it needs to be further developed in terms of identifying and analysing its factors, and evaluating its validity and reliability. Initiatives of future research in OPCC will require interdisciplinary research efforts and close cooperation with industry to further propose and rigorously evaluate instruments. Only then OPCC would be considered an evidence-based research topic that can be reliably used to evaluate, measure, and embed privacy in organisations.

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  • 12.
    Kitkowska, Agnieszka
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Shulman, Yefim
    Department of Industrial Engineering, Tel Aviv University, Israel.
    Martucci, Leonardo
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Wästlund, Erik
    Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Service Research Center (from 2013). Karlstad University, Faculty of Arts and Social Sciences (starting 2013), Department of Social and Psychological Studies (from 2013).
    Psychological Effects and Their Role in Online Privacy Interactions: A Review2020In: IEEE Access, E-ISSN 2169-3536, Vol. 8, p. 21236-21260Article in journal (Refereed)
    Abstract [en]

    Because of the increasing dependency on online technologies in even the most ordinary activities, people have to make privacy decisions during everyday online interactions. Visual design often influences their choices. Hence, it is in the hands of choice architects and designers to guide users towards specific decision outcomes. This “nudging” has gained much interest among scholars in interdisciplinary research, resulting in experimental studies with visual cues that may have the potential to alter attitudes and behaviors. Attitude and behavior changes are often attributed to several psychological effects manifesting in cognitive processing and decision-making. This article presents the results of a systematic literature review carried out to identify which psychological effects have been previously studied in the context of online privacy interactions. Subsequently, fifteen articles were selected and thoroughly reviewed, resulting in the identification of twenty psychological effects. The visual cues triggering these effects were recognized and classified against their capabilities to alter privacy attitudes and behaviors. Specifically, the visual cues were divided into two categories: privacy-enhancing and privacy-deteriorating. This review discusses the applicability of such cues in research and UI design. Further, the findings are discussed against the existing research on digital nudges. The authors conclude with a discussion on issues of research quality in the privacy-related field and outline the road to improvement.

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  • 13.
    Klima, Matej
    et al.
    Czech Technical University in Prague, Czech Republic.
    Bures, Miroslav
    Czech Technical University in Prague, Czech Republic.
    Frajtak, Karel
    Czech Technical University in Prague, Czech Republic.
    Rechtberger, Vaclav
    Czech Technical University in Prague Czech Republic.
    Trnka, Michal
    Czech Technical University in Prague, Czech Republic.
    Bellekens, Xavier
    Lupovis.io, Glasgow, U.K..
    Cerny, Tomas
    Baylor University, USA.
    Ahmed, Bestoun S.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Selected Code-Quality Characteristics and Metrics for Internet of Things Systems2022In: IEEE Access, E-ISSN 2169-3536, Vol. 10, p. 46144-46161Article in journal (Refereed)
    Abstract [en]

    Software code is present on multiple levels within current Internet of Things (IoT) systems. The quality of this code impacts system reliability, safety, maintainability, and other quality aspects. In this paper, we provide a comprehensive overview of code quality-related metrics, specifically revised for the context of IoT systems. These metrics are divided into main code quality categories: Size, redundancy, complexity, coupling, unit test coverage and effectiveness, cohesion, code readability, security, and code heterogeneity. The metrics are then linked to selected general quality characteristics from the ISO/IEC 25010:2011 standard by their possible impact on the quality and reliability of an IoT system, the principal layer of the system, the code levels and the main phases of the project to which they are relevant. This analysis is followed by a discussion of code smells and their relation to the presented metrics. The overview presented in the paper is the result of a thorough analysis and discussion of the author’s team with the involvement of external subject-matter experts in which a defined decision algorithm was followed. The primary result of the paper is an overview of the metrics accompanied by applicability notes related to the quality characteristics, the system layer, the level of the code, and the phase of the IoT project.

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  • 14.
    Mahjoubi, Ayeh
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ramaswamy, Arunselvan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    An Online Simulated Annealing-based Task Offloading Strategy for a Mobile Edge Architecture2024In: IEEE Access, E-ISSN 2169-3536, Vol. 12, p. 70707-70718Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel online task scheduling strategy called SATS, designed for a hierarchical Mobile Edge Computing (MEC) architecture. SATS utilizes a Simulated Annealing-based method for scheduling tasks and demonstrates that Simulated Annealing can be a viable solution for online task scheduling, not just for offline task scheduling. However, the paper also emphasizes that the effectiveness of SATS depends on the precision of service request predictions. The paper evaluates three types of predictors: neutral, conservative, and optimistic. It concludes that when using a conservative predictor that overestimates the number of service requests, SATS performs the best in terms of higher acceptance rates and shorter processing times. In fact, when using a conservative predictor, SATS can offer an acceptance ratio that is only 5% lower than what it could have been if SATS had known the frequency of service request arrivals beforehand and deviates less than 20% from this acceptance ratio in all conducted experiments.

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  • 15.
    Murmann, Patrick
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Tools for Achieving Usable Ex Post Transparency: A Survey2017In: IEEE Access, E-ISSN 2169-3536, Vol. 5, p. 22965-22991Article in journal (Refereed)
    Abstract [en]

    Transparency of personal data processing is a basic privacy principle and a right that is well acknowledged by data protection legislation, such as the EU general data protection regulation (GDPR). The objective of ex post transparency enhancing tools (TETs) is to provide users with insight about what data have been processed about them and what possible consequences might arise after their data have been revealed, that is, ex post. This survey assesses the state of the art in scientific literature of the usability of ex post TETs enhancing privacy and discusses them in terms of their common features and unique characteristics. The article first defines the scope of usable transparency in terms of relevant privacy principles for providing transparency by taking the GDPR as a point of reference, and usability principles that are important for achieving transparency. These principles for usable transparency serve as a reference for classifying and assessing the surveyed TETs. The retrieval and screening process of the publications is then described, as is the process for deriving the subsequent classification of the characteristics of the TETs. The survey not only looks into what is made transparent by the TETs but also how transparency is actually achieved. A main contribution of this survey is a proposed classification that assesses the TETs based on their functionality, implementation and evaluation as described in the literature. It concludes by discussing the trends and limitations of the surveyed TETs in regard to the defined scope of usable TETs and shows possible directions of future research for addressing these gaps. This survey provides researchers and developers of privacy enhancing technologies an overview of the characteristics of state of the art ex post TETs, on which they can base their work.

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    Murmann_Fischer-Hübner
  • 16.
    Salihu, Ibrahim-Anka
    et al.
    Department of Software Engineering, Faculty of Computer Science and Information Technology, Universiti Tun Hussein Onn Malaysia, Parit Raja, Malaysia.
    Ahmed, Bestoun S.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Zamli, Kamal Z
    Faculty of Computer Systems and Software Engineering, Universiti Malaysia Pahang, Gambang, Malaysia.
    Usman, Asmau
    Department of Software Engineering, Faculty of Computer Science and Information Technology, Universiti Tun Hussein Onn Malaysia, Parit Raja, Malaysia.
    AMOGA: A Static-Dynamic Model Generation Strategy for Mobile Apps Testing2019In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 17158-17173Article in journal (Refereed)
    Abstract [en]

    In the past few years, mobile devices have been increasingly replacing traditional computers, as their capabilities, such as CPU computation, memory, RAM size, and many more, are being enhanced almost to the level of conventional computers. These capabilities are being exploited by mobile apps developers to produce apps that offer more functionalities and optimized performance. To ensure acceptable quality and to meet their specifications (e.g., design), mobile apps need to be tested thoroughly. As the testing process is often tedious, test automation can be the key to alleviating such laborious activities. In the context of the Android-based mobile apps, researchers and practitioners have proposed many approaches to automate the testing process mainly on the creation of the test suite. Although useful, most existing approaches rely on reverse engineering a model of the application under test for test case creation. Often, such approaches exhibit a lack of comprehensiveness, as the application model does not capture the dynamic behavior of the applications extensively due to the incompleteness of reverse engineering approaches. To address this issue, this paper proposes AMOGA, a strategy that uses a hybrid, static-dynamic approach for generating a user interface model from mobile apps for model-based testing. AMOGA implements a novel crawling technique that uses the event list of UI element associated with each event to dynamically exercise the events ordering at the run time to explore the applications’ behavior. An experimental evaluation was performed to assess the effectiveness of our strategy by measuring the code coverage and the fault detection capability through the use of mutation testing concept. The results of the experimental assessment showed that AMOGA represents an alternative approach for model-based testing of mobile apps by generating comprehensive models to improve the coverage of the applications. The strategy proved its effectiveness by achievin...

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  • 17.
    Usman, Muhammad
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Ferlin, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Red Hat.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Taheri, Javid
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    A Survey on Observability of Distributed Edge & Container-based Microservices2022In: IEEE Access, E-ISSN 2169-3536, Vol. 10, p. 86904-86919Article in journal (Refereed)
    Abstract [en]

    Edge computing is proposed as a technical enabler for meeting emerging network technologies (such as 5G and Industrial Internet of Things), stringent application requirements and key performance indicators (KPIs). It aims to alleviate the problems associated with centralized cloud computing systems by placing computational resources to the network’s edge, closer to the users. However, the complexity of distributed edge infrastructures grows when hosting containerized workloads as microservices, resulting in hard to detect and troubleshoot outages on critical use cases such as industrial automation processes. Observability aims to support operators in managing and operating complex distributed infrastructures and microservices architectures by instrumenting end-to-end runtime performance. To the best of our knowledge, no survey article has been recently proposed for distributed edge and containerized microservices observability. Thus, this article surveys and classifies state-of-the-art solutions from various communities. Besides surveying state-of-the-art, this article also discusses the observability concept, requirements, and design considerations. Finally, we discuss open research issues as well as future research directions that will inspire additional research in this area. 

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  • 18.
    Voronkov, Artem
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Martucci, Leonardo
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Lindskog, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Measuring the Usability of Firewall Rule Sets2020In: IEEE Access, E-ISSN 2169-3536, p. 27106-27121Article in journal (Refereed)
    Abstract [en]

    Firewalls are computer systems that assess the network traffic using an ideally coherentand manageable set of rules. This study aims to provide means to measure the usability of firewall rulesets in terms of how easily IT professionals can understand and manage them. First, we conductedsemi-structured interviews with system administrators wherein we obtained the usability challenges relatedto the management of firewall rule sets. This was followed by the analysis of related work. The interviewresults were combined with the findings from the related work. Accordingly, we acquired four usabilityattributes related to the manageability of firewalls; these were formally defined. We tested and measured thecognitive aspects related to the structure and ordering of the rules through a user study. A third user studywith system administrators validated our metrics. It exhibited a very strong correlation between the metricsand how the administrators characterized usability.

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  • 19.
    Wairimu, Samuel
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Iwaya, Leonardo H
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Fritsch, Lothar
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Oslo Metropolitan University, Norway.
    Lindskog, Stefan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    On the Evaluation of Privacy Impact Assessment and Privacy Risk Assessment Methodologies: A Systematic Literature Review2024In: IEEE Access, E-ISSN 2169-3536, Vol. 12, p. 19625-19650Article, review/survey (Refereed)
    Abstract [en]

    Assessing privacy risks and incorporating privacy measures from the onset requires a comprehensive understanding of potential impacts on data subjects. Privacy Impact Assessments (PIAs) offer a systematic methodology for such purposes, which are closely related to Data Protection Impact Assessments (DPIAs), particularly outlined in Article 35 of the General Data Protection Regulation (GDPR). The core of a PIA is a Privacy Risk Assessment (PRA). PRAs can be integrated as part of full-fledged PIAs or independently developed to support PIA processes. Although these methodologies have been identified as essential enablers of privacy by design, their effectiveness has been criticized because of the lack of evidence of their rigorous and systematic evaluation. Hence, we conducted a Systematic Literature Review (SLR) to identify published PIA and PRA methodologies and assess how and to what extent they have been scientifically validated or evaluated. We found that these methodologies are rarely evaluated for their performance in practice, and most of them have only been validated in limited studies. Most validation evidence is found with PRA methodologies. Of the evaluated methodologies, PIAs were the most evaluated, where case studies were the predominant evaluation method. These evaluated methodologies can be easily transferred to an industrial setting or used by practitioners, as they provide evidence of their use in practice. In addition, the findings in this study can be used to inform researchers of the current state-of-the-art, and practitioners can understand the benefits and current limitations of the methodologies and adopt evidence-based practices. 

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  • 20.
    Wu, Hongjia
    et al.
    SimulaMet, NOR; OsloMet, NOR.
    Ferlin, Simone
    Ericsson AB, Radio Networks.
    Caso, Giuseppe
    Ericsson Research.
    Alay, Ozgu
    SimulaMet, NOR; University Oslo, NOR.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    A Survey on Multipath Transport Protocols Towards 5G Access Traffic Steering, Switching and Splitting2021In: IEEE Access, E-ISSN 2169-3536, Vol. 9, p. 164417-164439Article in journal (Refereed)
    Abstract [en]

    The fifth generation (5G) cellular network aims at providing very high data rates, ultra reliable low latency communications, and a vast increase of connection density. As one of the design trends towards these objectives, 5G exploits multi-connectivity, i.e., the concurrent use of multiple access networks. The Access Traffic Steering, Switching, and Splitting (ATSSS) architecture has recently been proposed to enable 5G multi-connectivity, and multipath transport protocols have emerged as a key ATSSS technology enabler. Within this context, this survey presents a detailed review of multipath transport protocols, identifies their existing and potential exploitation in ATSSS, and suggests their applicability for enhanced Mobile Broadband (eMBB) and Ultra Reliable Low Latency Communications (URLLC) services. To this end, we first review 5G background and current standardization activities around multi-connectivity and the ATSSS architecture. We then provide an in-depth review of multipath transport protocols, covering four core functionalities, i.e., path management, scheduling, congestion control, and reliable transfer. Based on the reviewed literature, we further discuss the integration of multipath transport into ATSSS to achieve eMBB and URLLC service requirements. Finally, we also point out major open research issues and discuss possible future directions.

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  • 21.
    Zverev, Mihail
    et al.
    Ikerlan Technology Research Centre, Basque Research Technology Alliance (BRTA), ESP.
    Garrido, Pablo
    Nemergent Solutions, ESP.
    Fernandez, Fatima
    Ikerlan Technology Research Centre, Basque Research Technology Alliance (BRTA), ESP.
    Bilbao, Josu
    Ikerlan Technology Research Centre, Basque Research Technology Alliance (BRTA), ESP.
    Alay, Ozgu
    University of Oslo, Nor.;Simula Metropolitan Center for Digital Engineering, Nor..
    Ferlin, Simone
    Ericsson AB.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Aguero, Ramon
    University of Cantabria, ESP.
    Robust QUIC: Integrating Practical Coding in a Low Latency Transport Protocol2021In: IEEE Access, E-ISSN 2169-3536, Vol. 9, p. 138225-138244Article in journal (Refereed)
    Abstract [en]

    We introduce rQUIC, an integration of the QUIC protocol and a coding module. rQUIC has been designed to feature different coding/decoding schemes and is implemented in go language. We conducted an extensive measurement campaign to provide a thorough characterization of the proposed solution. We compared the performance of rQUIC with that of the original QUIC protocol for different underlying network conditions as well as different traffic patterns. Our results show that rQUIC not only yields a relevant performance gain (shorter delays), especially when network conditions worsen, but also ensures a more predictable behavior. For bulk transfer (long flows), the delay reduction almost reached 70% when the frame error rate was 5%, while under similar conditions, the gain for short flows (web navigation) was approximate to 55%. In the case of video streaming, the QoE gain (p1203 metric) was, approximately, 50%.

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