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  • 201.
    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.

  • 202.
    Derevyanchuk, E.
    et al.
    Russia .
    Smirnov, Yurij
    Russia.
    Shestopalov, Yuri
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Permittivity determination of thin multi-sectional diaphragms in a rectangular waveguide2013In: Proceedings of the International Conference Days on Diffraction 2013, 2013, p. 32-35, article id 6712799Conference paper (Refereed)
    Abstract [en]

    In this paper we consider the inverse problem of the permittivity determination of thin multisectional diaphragm in a rectangular waveguide. We perform a detailed analysis for one-, two- and three-sectional thin diaphragms. Numerical results are presented.

  • 203. Dietz, L. W.
    et al.
    Manner, J.
    Harrer, S.
    Lenhard, Jörg
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Teaching clean code2018In: Combined Proceedings of the Workshops of the German Software Engineering Conference 2018 (SE 2018) / [ed] Krusche S., Schneider K., Kuhrmann M., Heinrich R., Jung R. et al, CEUR-WS , 2018, p. 24-27Conference paper (Refereed)
    Abstract [en]

    Learning programming is hard - teaching it well is even more challenging. At university, the focus is often on functional correctness and neglects the topic of clean and maintainable code, despite the dire need for developers with this skill set within the software industry. We present a feedbackdriven teaching concept for college students in their second to third year that we have applied and refined successfully over a period of more than six years and for which received the faculty's teaching award. Evaluating the learning process within a semester of student submissions (n=18) with static code analysis tools shows satisfying progress. Identifying the correction of the in-semester programming assignments as the bottleneck for scaling the number of students in the course, we propose using a knowledge base of code examples to decrease the time to feedback and increase feedback quality. From our experience in assessing student code, we have compiled such a knowledge base with the typical issues of Java learners' code in the format of before/after comparisons. By simply referencing the problem to the student, the quality of feedback can be improved, since such comparisons let the student understand the problem and the rationale behind the solution. Further speed-up is achieved by using a curated list of static code analysis checks to help the corrector in identifying violations in the code swiftly. We see this work as a foundational step towards online courses with hundreds of students learning how to write clean code.

  • 204.
    Dobell, Elaine
    et al.
    Saolta University Health Care Group, Ireland & University of Limerick, Ireland.
    Herold, Sebastian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Buckley, Jim
    University of Limerick, Ireland.
    Spreadsheet Error Types and Their Prevalence in a Healthcare Context2018In: Journal of Organizational and End User Computing, ISSN 1546-2234, E-ISSN 1546-5012, Vol. 30, no 2, p. 20-42Article in journal (Refereed)
    Abstract [en]

    Spreadsheets are commonly used to inform decision making across many business sectors, despite the fact that research performed in the financial sector has shown that they are quite error-prone. However, few studies have investigated spreadsheet errors and their impact in other domains, like the healthcare sector. This article derives a lifecycle-stage classification scheme of spreadsheet error types based on an aggregation of, and extension of, existing classifications. Based on these classifications, a case study is then presented, performed to investigate the prevalence of these spreadsheet error types in an Irish healthcare setting. Results reveal that more than 90% of the spreadsheets studied contained ` bottom-line' errors and the average cell-error rate was 13%. There was also a correlation between increased perceived impact of the spreadsheets and the number of errors identified. Recommendations from this research include providing spreadsheet training and guidelines for developers and users, and systematically managing and auditing spreadsheet development and use.

  • 205.
    Dobrijevic, Ognjen
    et al.
    University of Zagreb, Croatia.
    Kassler, Andreas
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Skorin-Kapov, Lea
    University of Zagreb, Croatia.
    Matijasevic, Maja
    University of Zagreb, Croatia.
    QoE-Driven Path Optimization Model for Multimedia Services2014In: Wired/Wireless Internet Communications : 12th International Conference, WIWIK14, Paris, FRANCE, May 26-28, 2014 Proceedings, Springer, 2014, Vol. 8458, p. 134-147Conference paper (Refereed)
    Abstract [en]

    When delivering multimedia services over Internet, different media types are impacted by resource limitations in a different way. While an interactive audio service calls for low-latency communication, video streams should be routed over network paths with sufficient capacity. However, in current networks flows towards the same destination follow the same path, which may lead to a suboptimal resource utilization that effectively penalizes end-users' quality of experience (QoE). This paper proposes Q-POINT, a QoE-driven path optimization model to fairly maximize aggregated end-user QoE for competing clients' service flows by calculating the best path for each flow, subject to resource constraints. We formulate the problem as a mixed integer linear program integrating QoE models for audio, video and data transfer. Such an approach can be leveraged within the software-defined networking paradigm, which provides a control plane to orchestrate path set-up. We evaluate our model and illustrate its benefits over shortest path selection.

  • 206.
    Doganay, Kivanc
    et al.
    SICS Swedish ICT AB, Sweden; Mälardalen University, Sweden..
    Eldh, Sigrid
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Ericsson AB, Sweden.
    Afzal, Wasif
    Mälardalen University, Sweden.
    Bohlin, Markus
    SICS Swedish ICT AB, Sweden; Mälardalen University, Sweden.
    Search-Based Testing for Embedded Telecom Software with Complex Input Structures2014In: Testing Software and Systems (Ictss 2014) / [ed] Merayo, MG & DeOca, EM, Springer, 2014, p. 205-210Conference paper (Refereed)
    Abstract [en]

    In this paper, we discuss the application of search-based software testing techniques for unit level testing of a real-world telecommunication middleware at Ericsson. Our current implementation analyzes the existing test cases to handle non-trivial variables such as uninitialized pointers, and to discover any setup code that needs to run before the actual test case, such as setting global system parameters. Hill climbing (HC) and (1+1) evolutionary algorithm (EA) metaheuristic search algorithms are used to generate input data for branch coverage. We compare HC, (1+1) EA, and random search with respect to effectiveness, measured as branch coverage, and efficiency, measured as number of executions needed. Difficulties arising from the specialized execution environment and the adaptations for handling these problems are also discussed.

  • 207.
    Drašar, Martin
    et al.
    Institute of Computer Science, Masaryk University, Czech Republic.
    Vykopal, Jan
    Institute of Computer Science, Masaryk University, Czech Republic.
    Winter, Philipp
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Flow-based Brute-force Attack Detection2013In: Advances in IT Early Warning / [ed] Peter Schoo, Markus Zeilinger & Eckehard Hermann, Fraunhofer Verlag , 2013, 1Chapter in book (Other academic)
    Abstract [en]

    Brute-force attacks are a prevalent phenomenon that is getting harderto successfully detect on a network level due to increasing volume and en-cryption of network traffic and growing ubiquity of high-speed networks.Although the research in this field advanced considerably, there still remainclasses of attacks that are undetectable. In this chapter, we present sev-eral methods for the detection of brute-force attacks based on the analysisof network flows. We discuss their strengths and shortcomings as well asshortcomings of flow-based methods in general. We also demonstrate thefragility of some methods by introducing detection evasion techniques.

  • 208.
    Duong, M. H.
    et al.
    University of Warwick, UK.
    Muntean, Adrian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Richardson, Omar
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Discrete and continuum links to a nonlinear coupled transport problem of interacting populations2017In: The European Physical Journal Special Topics, ISSN 1951-6355, E-ISSN 1951-6401, Vol. 226, no 10, p. 2345-2357Article in journal (Refereed)
    Abstract [en]

    We are interested in exploring interacting particle systemsthat can be seen as microscopic models for a particular structure ofcoupled transport flux arising when different populations are jointlyevolving. The scenarios we have in mind are inspired by the dynamicsof pedestrian flows in open spaces and are intimately connectedto cross-diffusion and thermo-diffusion problems holding a variationalstructure. The tools we use include a suitable structure of the relativeentropy controlling TV-norms, the construction of Lyapunov functionalsand particular closed-form solutions to nonlinear transport equations,a hydrodynamics limiting procedure due to Philipowski, as wellas the construction of numerical approximates to both the continuumlimit problem in 2D and to the original interacting particle systems.

  • 209.
    Eden, Michael
    et al.
    University of Bremen, Germany.
    Muntean, Adrian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Corrector estimates for the homogenization of a two-scale thermoelasticity problem with a priori known phase transformations2017In: Electronic Journal of Differential Equations, ISSN 1550-6150, E-ISSN 1072-6691, no 57, p. 1-21Article in journal (Refereed)
    Abstract [en]

    We investigate corrector estimates for the solutions of a thermoelasticity problem posed in a highly heterogeneous two-phase medium and its corresponding two-scale thermoelasticity model which was derived in [11] by two-scale convergence arguments. The medium in question consists of a connected matrix with disconnected, initially periodically distributed inclusions separated by a sharp interface undergoing a priori known phase transformations. While such estimates seem not to be obtainable in the fully coupled setting, we show that for some simplified scenarios optimal convergence rates can be proven rigorously. The main technique for the proofs are energy estimates using special reconstructions of two-scale functions and particular operator estimates for periodic functions with zero average. Here, additional regularity results for the involved functions are necessary.

  • 210.
    Eden, Michael
    et al.
    University of Bremen.
    Muntean, Adrian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Homogenization of a fully coupled thermoelasticity problem for a highly heterogeneous medium with a priori known phase transformations2017In: Mathematical methods in the applied sciences, ISSN 0170-4214, E-ISSN 1099-1476, Vol. 40, no 11, p. 3955-3972Article in journal (Refereed)
    Abstract [en]

    We investigate a linear, fully coupled thermoelasticity problem for a highly heterogeneous, two-phase medium. The medium in question consists of a connected matrix with disconnected, initially periodically distributed inclusions separated by a sharp interface undergoing an a prioriknown interface movement because of phase transformations. After transforming the moving geometry to an ϵ-periodic, fixed reference domain, we establish the well-posedness of the model and derive a number of ϵ-independent a priori estimates. Via a two-scale convergence argument, we then show that the ϵ-dependent solutions converge to solutions of a corresponding upscaled model with distributed time-dependent microstructures.

  • 211.
    Edvardsson, Elisabet
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Modular forms for triangle groups2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Modular forms are important in different areas of mathematics and theoretical physics. The theory is well known for the modular group PSL(2,Z), but is also of interest for other Fuchsian groups. In this thesis we will be interested in triangle groups with a cusp. We review some theory about mapping of hyperbolic triangles in order to derive an expression for the Hauptmodul of a triangle group, and use this to write a SageMath-program that calculates the Fourier series of the Hauptmodul. We then review some of the results presented in [4] that describe generalizations of well known concepts such as the Eisenstein series, the Serre derivative and some general results about the algebra of modular forms for triangle groups with a cusp. We correct some of the mistakes made in [4] and prove some further properties of the generators of the algebra of modular forms in the case of Hecke groups. Then we use the results from [4] to write a SageMath-program that calculates the Fourier series of the generators of the algebra of modular forms for triangle groups with a cusp and that also finds the relations between the generators in the special case of Hecke groups. Using the results from this program, we present some conjectures concerning the generators of the algebra of modular forms for a Hecke group, which, if proven to be true, give us a generalization of some of the Ramanujan equations. We conclude by explicitly calculating the generalized Ramanujan equations for the first few Hecke groups.

  • 212.
    Edvardsson, Elisabet
    et al.
    Stockholms universitet.
    Mossberg, Eva
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    The Q-toothpick Cellular Automaton2019In: JOURNAL OF CELLULAR AUTOMATA, ISSN 1557-5969, Vol. 14, no 1-2, p. 51-68Article in journal (Refereed)
    Abstract [en]

    In a toothpick-type cellular automaton, a shape is drawn, and then at each time-step copies of the same shape are attached at certain predetermined places. The resulting pattern exhibits unexpected growth properties. We investigate the fractal-like large-scale behavior of the Q-toothpick cellular automaton, which is built from quarter circles, with starting configurations consisting of an arbitrary number of quarter circles. In this paper, we prove that infinitely long barriers of quarter circles arise in the pattern, and divide it into non-interacting triangular parts. Furthermore, we show that the behavior of these triangular parts is described by the one-dimensional elementary cellular automaton rule 18 and is related to the Sierpinski triangle.

  • 213.
    Eklund, Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University.
    Latency Reduction for Soft Real-Time Traffic using SCTP Multihoming2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    More and more so-called soft real-time traffic is being sent over IP-based networks. The bursty, data-limited traffic pattern as well as the latency requirements from this traffic present challenges to the traditional communication techniques, designed for bulk traffic without considering latency.

    To meet the requirements from soft real-time traffic, in particular from telephony signaling, the Stream Control Transmission Protocol (SCTP) was designed. Its support for connectivity to multiple networks, i.e., multihoming, provides robustness and opens up for concurrent multipath transfer (CMT) over multiple paths. Since SCTP is a general transport protocol, it also enables for handover of media sessions between heterogeneous networks. Migrating an ongoing session to a new network, as well as CMT with minimal latency, requires tuning of several protocol parameters and mechanisms.

    This thesis addresses latency reduction for soft real-time traffic using SCTP multihoming from three perspectives. The first focus is on latency for signaling traffic in case of path failure, where a path switch, a failover, occurs. We regard quick failure detection as well as rapid startup on the failover target path. The results indicate that by careful parameter tuning, the failover time may be significantly reduced. The second focus in the thesis is on latency for signaling traffic using CMT. To this end, we address sender-side scheduling. We evaluate some existing schedulers, and design a dynamic stream-aware scheduler. The results indicate that the dynamic stream-aware scheduler may provide significantly improved latency in unbalanced networks. Finally, we target multihomed SCTP to provide for handover of a media session between heterogeneous wireless networks in a mobile scenario. We implement a handover scheme and our investigation shows that SCTP could provide for seamless handover of a media session at walking speed.

  • 214.
    Eklund, Johan
    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 Economic Sciences, Communication and IT, Department of Computer Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunstrom, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Efficient Scheduling to Reduce Latency for Signaling Traffic using CMT-SCTP2016In: 27th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), September 4-7, Valencia, Spain, IEEE, 2016, p. 2127-2132Conference paper (Refereed)
    Abstract [en]

    To mitigate delay spikes during transmission of bursty signaling traffic, concurrent multipath transmission (CMT) over several paths in parallel could be an option. Still, unordered delivery is a well known problem when concurrently transmitting data over asymmetric network paths, leading to extra delay due to Head-of-Line Blocking (HoLB). The Stream Control Transmission Protocol (SCTP), designed as a carrier for signaling traffic over IP, is currently being extended with support for CMT (CMT-SCTP). To reduce the impact of HoLB, SCTP has support for transmission of separate data flows, called SCTP streams. In this paper, we address sender scheduling to optimize latency for signaling traffic using CMT-SCTP. We present dynamic stream-aware (DS) scheduling, which utilizes the SCTP stream concept, and continuously considers the current network status as well as the data load to make scheduling decisions. We implement a DS scheduler and compare it against some existing schedulers. Our investigation suggests that DS scheduling could significantly reduce latency compared to dynamic path scheduling that does not consider streams. Moreover, we show that naive round-robin scheduling may provide low latency over symmetric network paths, but may transmit data on non-beneficial asymmetric network paths leading to increased latency. Finally, our results show that a static stream based approach, found beneficial for bulk traffic, is not appropriate for bursty signaling traffic. 

  • 215.
    Eklund, Johan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    On the Impact of Data Scheduling to Reduce Latency for Telephony Signaling Traffic using CMT-SCTP2015In: The 11th Swedish National Computer Networking Workshop (SNCNW), Karlstad, Sweden, May 28-29, 2015., 2015Conference paper (Other academic)
    Abstract [en]

    SCTP is a transport protocol targeted for telephony signaling traffic. Although SCTP from its inception supported multihoming, it has until now not supported concurrent mul- tipath transfer. However, this is about to change: Currently a standard for concurrent multipath transfer is underway. Since it is unclear whether concurrent multipath transfer could reduce transmission latency, this paper evaluates two algorithms for scheduling signaling traffic for transmission. We find that the mechanisms may provide good performance and to some extent enables for service differentiation. Still, the results indicate that unpredictable traffic require dynamic scheduling.

  • 216.
    Eklund, Johan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Department of Computer Science.
    Stream-aware Scheduling to Improve Latency for Signaling Traffic using CMT-SCTP2016Conference paper (Refereed)
    Abstract [en]

    To mitigate delay spikes during transmission ofbursty signaling traffic, concurrent multipath transmission(CMT) over several paths in parallel could be an option. Still,unordered delivery is a well known problem when transmittingover asymmetric network paths, leading to extra delay due toHead-of-Line Blocking (HoLB). The Stream Control TransmissionProtocol (SCTP) is designed as a carrier for signaling trafficover IP to reduce the impact of HoLB. SCTP has support fortransmission of separate flows, called SCTP streams. SCTP iscurrently being extended with support for CMT (CMT-SCTP). Inthis paper, we address sender scheduling to optimize latency forsignaling traffic over CMT-SCTP. We present dynamic streamaware(DS) scheduling, which utilizes the SCTP stream concept,and continuously considers the current network status as well asthe data load to make scheduling decisions. We implement a DSScheduler and compare it against a dynamic path (DP) schedulerthat does not consider streams. Our investigation shows that DSscheduling could significantly reduce latency compared to a DPscheduler.

  • 217.
    Eklund, Johan
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT.
    Grinnemo, Karl-Johan
    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).
    Using multiple paths in SCTP to reduce latency for signaling traffic2018In: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 129, p. 184-196Article in journal (Refereed)
    Abstract [en]

    The increase in traffic volumes as well as the heterogeneity in network infrastructure in the upcoming 5G cellular networks will lead to a dramatic increase in volumes of control traffic, i.e., signaling traffic, in the networks. Moreover, the increasing number of low-power devices with an on-off behavior to save energy will generate extra control traffic. These increased traffic volumes for signaling traffic, often generated as bursts of messages, will challenge the signaling application timing requirements on transmission. One of the major transport protocols deployed for signaling traffic in cellular networks is the Stream Control Transmission Protocol (SCTP), with support for multiple paths as well as for independent data flows. This paper evaluates transmission over several paths in SCTP to keep the latency low despite increasing traffic volumes. We explore different transmission strategies and find that concurrent multipath transfer over several paths will significantly reduce latency for transmission over network paths with the same or similar delay. Still, over heterogeneous paths, careful, continuous sender scheduling is crucial to keep latency low. To this end, we design and evaluate a sender scheduler that considers path characteristics as well as queuing status and data flows of different priority to make scheduling decisions. Our results indicate that by careful dynamic sender scheduling, concurrent multipath transfer could lead to reduced latency for signaling traffic irrespective of path or traffic characteristics.

  • 218.
    Eldh, Sigrid
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science. Ericsson AB, Sweden.
    Some researcher considerations when conducting empirical studies in industry2013In: Conducting Empirical Studies in Industry (CESI), Elsevier, 2013, p. 69-70, article id 6618476Conference paper (Refereed)
    Abstract [en]

    Research collaborations must be set up for a win-win relationship, avoiding many hurdles along the way. In this short paper the goal is to identify some considerations when conducting empirical studies in industry. These considerations deal with problem solution approaches, communication focus, unpleasant results, mismatching interpretations and scope, business aspects and some evaluation criteria for a successful collaboration.

  • 219.
    Eldh, Sigrid
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Andersson, Kenneth
    Ermedahl, Andreas
    Wiklund, Kristian
    Towards a Test Automation Improvement Model (TAIM)2014In: Proceedings - IEEE 7th International Conference on Software Testing, Verification and Validation Workshops, ICSTW 2014, p. 337-342Article in journal (Refereed)
    Abstract [en]

    In agile software development, industries are becoming more dependent on automated test suites. Thus, the test code quality is an important factor for the overall system quality and maintainability. We propose a Test Automation Improvement Model (TAIM) defining ten key areas and one general area. Each area should be based on measurements, to fill the gap of existing assessments models. The main contribution of this paper is to provide the outline of TAIM and present our intermediate results and some initial metrics to support our model. Our initial target has been the key area targeting implementation and structure of test code. We have used common static measurements to compare the test code and the source code of a unit test automation suite being part of a large complex telecom subsystem. Our intermediate results show that it is possible to outline such an improvement model and our metrics approach seems promising. However, to get a generic useful model to aid test automation evolution and provide for comparable measurements, many problems still remain to be solved. TAIM can as such be viewed as a framework to guide the research on metrics for test automation artifacts. 

  • 220.
    Endo Kokubun, M. A.
    et al.
    University of Bergen, Norway.
    Muntean, Adrian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Radu, F. A.
    University of Bergen, Norway.
    Kumar, Kundan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Pop, I. S.
    University of Hasselt, Belgium.
    Keilegavlen, E.
    University of Bergen, Norway.
    Spildo, K.
    University of Bergen, Norway.
    A pore-scale study of transport of inertial particles by water in porous media2019In: Chemical Engineering Science, ISSN 0009-2509, E-ISSN 1873-4405, Vol. 207, p. 397-409Article in journal (Refereed)
    Abstract [en]

    We study the transport of inertial particles in water flow in porous media. Our interest lies in understanding the accumulation of particles including the possibility of clogging. We propose that accumulation can be a result of hydrodynamic effects: the tortuous paths of the porous medium generate regions of dominating strain, which favour the accumulation of particles. Numerical simulations show that essentially two accumulation regimes are identified: for low and for high flow velocities. When particles accumulate at the entrance of a pore throat (high-velocity region), a clog is formed. This significantly modifies the flow, as the partial blockage of the pore causes a local redistribution of pressure, which diverts the upstream water flow into neighbouring pores. Moreover, we show that accumulation in high velocity regions occurs in heterogeneous media, but not in homogeneous media, where we refer to homogeneity with respect to the distribution of the pore throat diameters.

  • 221.
    Engman, Anton
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Olsson, Anders
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Utveckling av testmiljö för kommunikation inom hälso- och sjukvården med stöd för standarden FHIR2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In order for Swedish healthcare systems to communicate, Inera, a company owned by the Swedish Municipalities and County Council (SKL), has formed a standard on how care information should be structured. This standard is called Rules for interoperability in health and care - technical instructions (RIVTA) and consists of a set of service contracts. The weakness of with RIVTA is that it does not extend beyond Sweden's borders. Therefore, regions (former county councils) and municipalities look at a new international standard called Fast Healthcare Interoperability Resources (FHIR). The study's client Nordic Medtest is a company that tests and quality-assures software in Swedish healthcare and care. Nordic Medtest wants to be at the forefront of FHIR and wants to create an environment where their clients can test their systems. The goal of this study is to translate a limited amount of two service contracts for RIVTA, the contracts getObservations and getActivities to corresponding structures in FHIR. In parallel with this a test environment for these two translated service contracts will be developed. A user will have the ability to request the two translated contracts through an interface which will present the information in the requested contracts. Together with the translation of the two service contracts and test environment development a testing strategy will be developed with the aim to ensure a correct translation and a quality safe test environment.

  • 222.
    Engström, Arne
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Betydelsen av att klara matematiken i skolan2017In: Skolhälsan, ISSN 0284-284X, no 4, p. 18-19Article in journal (Other (popular science, discussion, etc.))
  • 223.
    Engström, Arne
    Karlstad University, Faculty of Technology and Science. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Elever med mycket låga prestationer i matematik: En pilotstudie av ämnesprovet i årskurs 32017Report (Refereed)
    Abstract [sv]

    Låga prestationer i matematik är en av de europeiska utbildningssystemens stora utmaningar. Det råder stor samstämmighet om vikten av tidig upptäckt och insats för elever som är i riskzonen för att utveckla skolsvårigheter. Ett medel för detta är de nationella proven i matematik. I föreliggande rapport redogörs för en pilotstudie av elever med mycket låga prestationer på ämnesprovet i matematik för årskurs 3 i en utvald kommun. Elevernas resultat på ämnesprovet, könsskillnader samt förekomst av särskilt stöd inventeras i studien. Resultatet pekar på att situationen för elever som tidigt uppvisar mycket låga prestationer behöver uppmärksammas. De riskerar att misslyckas med att utveckla grundläggande färdigheter i skolan till en tillfredsställande nivå. Samtidigt reser studien också frågan om alla elever har förutsättningar att nå grundskolans kravnivå.

  • 224.
    Engström, Arne
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Från dyskalkyli till låga prestationer i matematik: Arvet efter Olof Magne2016Report (Refereed)
    Abstract [sv]

    Matematiksvårigheter eller låga prestationer i matematik är en av de stora utmaningar som de europeiska utbildningssystemen står inför idag. Att misslyckas med skolmatematiken får stora konsekvenser för både elever och samhället.

    Den som kanske mer än någon annan kommit att personifiera den svenska forskningen om matematiksvårigheter är Olof Magne. Under 1950-talet arbetade han med de så kallade Göteborgsundersökningarna som omfattade 6000 folkskoleelever. Dessa följdes sedan upp av en serie interventionsstudier under 1960-talet riktade mot räknesvaga elever. Därefter påbörjade han arbetet med en kognitiv taxonomi för den elementära matematikundervisningen.

    De hypoteser som Magne ställde i Göteborgsundersökningarna följdes upp i det stora Medelsta-projektet. Här kan man följa utvecklingen av grundskolelevers matematikkunskaper under en period av 25 år. Den första studien i projektet gjordes 1977 och replikerades sedan vid två tillfällen 1986 och 2002.

    Syftet med föreliggande rapport är att beskriva och analysera Olof Magnes forskning inom området låga prestationer i matematik – vilka var frågorna, metoderna och resultatet samt var står vi idag? De frågor som restes i Magnes inledande studier för mer än 60 år sedan fortsätter att sysselsätta oss än idag. 

  • 225.
    Engström, Arne
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    RC is a theory of learning, not teaching2014In: Constructivist Foundations, ISSN 1782-348X, E-ISSN 1782-348X, Vol. 9, no 3, p. 314-316Article in journal (Refereed)
    Abstract [en]

    The concept of "constructivist teaching" seems unattainable for two reasons: a philosophical and an empirical one. Also, Hugh Gash's survey is not so much about radical constructivism in education, but a review of different connected ideas labeled "constructivism" that have dominated the educational field.

  • 226.
    Engström, Arne
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Semiotiska perspektiv i matematikdidaktik: En introduktion2018Report (Refereed)
    Abstract [sv]

    Semiotiska perspektiv i matematikdidaktik har fått en ökad uppmärksamhet under senare år. I flera länder finns en livaktig forskning på området. I Sverige är semiotiska perspektiv inom matematikdidaktiken ännu svagt utvecklad. Föreliggande rapport syftar till att introducera semiotiska perspektiv inom den matematikdidaktiska forskningen. Teoretiskt inspireras dessa perspektiv av Ferdinand de Saussures och Charles S. Peirce arbeten.

    Människor uttrycker matematiska tankar med hjälp av tecken av olika slag. Ett tecken står för någonting. Detta någonting är i matematik ett matematiskt objekt. Matematik kan uppfattas som en generalisering av tecken eller representationssystem. En väsentlig del av den moderna matematiken handlar om symbolisering. Det är inte främst en abstraktion av den direkta verkligheten, utan om en kedja av abstraktioner. Ett matematiskt objekt eller sakförhållande kan bara förstås och kommuniceras när det representeras och tolkas i någon form. Spänningsfältet mellan sakförhållandet, representationen och tolkningen gör därför semiotiska perspektiv mycket intressanta för matematikdidaktisk forskning.

  • 227.
    Engström, Arne
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Specialpedagogiska frågeställningar i matematik2015Report (Other academic)
    Abstract [sv]

    Låga prestationer i matematik är en av de stora utmaningar som de europeiska utbildningssystemen står inför. Det är en fråga som inte bara handlar om undervisningens effektivitet utan också om att skapa ett rättvist utbildningssystem. Alla moderna utbildningssystem står inför ett antal grundläggande motsättningar, eller dilemman, som i egentlig mening inte kan lösas, men likväl måste hanteras. I en skola för alla är elevernas olikheter ett grundläggande dilemma. Den gamla skolans sätt att hantera olikheterna, genom särskiljning och segregerande lösningar, har vi lämnat bakom oss. De nya utmaningar som utbildningssystemet står inför måste hanteras på andra sätt.

    I rapporten introduceras några specialpedagogiska frågeställningar i matematik. Matematiken fungerar som ett kritiskt filter och systemindikator för ett skolsystem. Att misslyckas i matematik får ofta större och vidare konsekvenser än att misslyckas i andra ämnen.  Låga prestationer betraktas i rapporten som ett socialt problemfält. Rapporten vänder sig såväl till lärarstuderande som till verksamma lärare, som önskar en lättillgänglig introduktion till frågeställningar som lärare i matematik, speciallärare eller specialpedagoger behöver orientera sig om och ta ställning till i sin yrkesutövning.

  • 228.
    Ensafi, Roya
    et al.
    University of New Mexico.
    Winter, Philipp
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Mueen, Abdullah
    University of New Mexico.
    Crandall, Jedidiah R.
    University of New Mexico.
    Large-scale Spatiotemporal Characterization ofInconsistencies in the World's Largest Firewall2014Report (Other academic)
    Abstract [en]

    A nation-scale firewall, colloquially referred to asthe “Great Firewall of China,” implements many different types of censorship and content filtering to control China’s Internet traffic. Past work has shown that the firewall occasionally fails. In other words, sometimes clients in China are able to reach blacklisted servers outside of China. This phenomenon has not yet been characterized because it is infeasible to find a large and geographically diverse set of clients in China from which to test connectivity. In this paper, we overcome this challenge by using hybrid idle scan techniques that are able to measure connectivity between a remote client and an arbitrary server, neither of which are under the control of the researcher performing measurements. In addition to hybrid idle scans, we present and employ a novel side channel in the Linux kernel’s SYN backlog. We demonstrate both techniques by measuring the reachability of the Tor network which is known to be blocked in China. Our measurements reveal that 1) failures in the firewall occur throughout the entire country without any conspicuous geographical patterns, 2) a network block in China appears to have unfiltered access to parts of the Tor network, and 3) the filtering seems to be mostly centralized at the level of Internet exchange points. Our work also answers many other open questions about the Great Firewall’s architecture and implementation.

  • 229.
    Evers, J. H. M.
    et al.
    Simon Fraser University, Canada; Dalhousie University, Canada; Eindhoven University of Technology, Netherlands.
    Hille, S. C.
    Leiden University, Netherlands.
    Muntean, Adrian
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Measure-valued mass evolution problems with flux boundary conditions and solution-dependent velocities2016In: SIAM Journal on Mathematical Analysis, ISSN 0036-1410, E-ISSN 1095-7154, Vol. 48, no 3, p. 1929-1953Article in journal (Refereed)
    Abstract [en]

    In this paper we prove well-posedness for a measure-valued continuity equation with solution-dependent velocity and flux boundary conditions, posed on a bounded one-dimensional domain. We generalize the results of an earlier paper [J. Differential Equations, 259 (2015), pp. 10681097] to settings where the dynamics are driven by interactions. In a forward-Euler-like approach, we construct a time-discretized version of the original problem and employ those results as a building block within each subinterval. A limit solution is obtained as the mesh size of the time discretization goes to zero. Moreover, the limit is independent of the specific way of partitioning the time interval [0, T]. This paper is partially based on results presented in Chapter 5 of [Evolution Equations for Systems Governed by Social Interactions, Ph.D. thesis, Eindhoven University of Technology, 2015], while a number of issues that were still open there are now resolved.

  • 230.
    Fagrell, Amanda
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Taluppfattningens roll i elevers lärande: En kvalitativ intervjustudie som undersöker om elevers taluppfattningsförmåga påverkar deras resultat i undervsiningen kring tal i bråkform.2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This degree project will study students' number sense based on teacher experiences from teaching fractions and if it affects the outcome. It will also highlight a number of common difficulties that the students may encounter but also how the teaching can be designed to support the students. The collection of the material on which the result is based has been received through qualitative interviews with active mathematics teachers in grade four to six. In order to investigate whether pupils' number sense affects the results in learning fractions, the theoretical framework number sense will be used. Number sense is created by McIntosh, Reys and Reys (1992) and is a tool for analyzing students' knowledge of understanding numbers, understanding operations, and making calculations with numbers. During the analysis of the data, teachers 'responses were documented in a table showing whether any of the student difficulties that became visible matched the categories for a good number sense.

  • 231.
    Fahlgren, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Designing for the integration of dynamic software environments in the teaching of mathematics2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis concerns the challenge of integrating dynamic software environments into the teaching of mathematics. It investigates particular aspects of the design of tasks which employ this type of computer-based system, with a focus on improvement, both of the tasks themselves and of the design process through which they are developed and refined.

    The thesis reports two research projects: a small initial one preceding a larger main project. The initial case study, involving two graduate students in mathematics, develops a task design model for geometrical locus problems. The main study constitutes the first iteration of a design-based study, conducted in collaboration with four upper-secondary school teachers and their classes. It seeks to identify task design characteristics that foster students’ mathematical reasoning and proficient use of software tools, and examines teachers’ organisation of ‘follow-up’ lessons.

    The findings concern three particular aspects: features of tasks and task environment relevant to developing a specific plan of action for a lesson; orchestration of a particular task environment to support the instrumental genesis of specific dynamic software tools; how to follow up students’ work on computer-based tasks in a whole-class discussion.

  • 232.
    Fahlgren, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Instrumental genesis concerning scales and scaling in a dynamic mathematics software environment2015In: Proceedings of the Ninth Congress of European Research in Mathematics Education / [ed] K. Krainer, N. Vondrova, Prague: European Society for Research in Mathematics Education, 2015, p. 2347-2353Conference paper (Refereed)
    Abstract [en]

    It is recognized that the process in which an artefact becomes an instrument for a user, denoted as instrumental genesis, is a complex process. The aim of this paper is to identify elements of the process of instrumental genesis when students are dealing with scales and scaling issues in a dynamic mathematics software environment. This study involves four upper secondary school teachers and their classes. By observing the students’ instrumented techniques while working with tasks designed with a hypothetical instrumental genesis in mind, some key elements are identified.

  • 233.
    Fahlgren, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Redesigning task sequences to support instrumental genesis in the use of movable points and slider bars2017In: The International Journal for Technology in Mathematics Education, ISSN 1744-2710, E-ISSN 2045-2519, Vol. 24, no 1, p. 3-15Article in journal (Refereed)
  • 234.
    Fahlgren, Maria
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Teachers’ didactical intention and instrumental orchestrations for ‘follow-up’ lessonsManuscript (preprint) (Other academic)
  • 235.
    Fahlgren, Maria
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013).
    Brunström, Mats
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    A Model for Task Design with Focus on Exploration,Explanation, and Generalization in a Dynamic GeometryEnvironment2014In: Technology, Knowledge and Learning, ISSN 2211-1662, E-ISSN 2211-1670, Vol. 19, no 3, p. 287-315Article in journal (Refereed)
    Abstract [en]

    The increasing availability of new technologies in schools provides new possibilities

    for the integration of technology in mathematics education. However, research

    has shown that there is a need for new kinds of task that utilize the affordances provided by

    new technology. Numerous studies have demonstrated that dynamic geometry environments

    provide opportunities for students to engage in mathematical activities such as

    exploration, conjecturing, explanation, and generalization. This paper presents a model for

    design of tasks that promote these kinds of mathematical activity, especially tasks that

    foster students to make generalizations. This model has been primarily developed to suit

    the use of dynamic environments in tackling geometrical locus problems. The model was

    initially constructed in the light of previous literature. This initial model was used to design

    a concrete example of such a task situation which was tested in action through a case study

    with two doctoral students. Findings from this case study were used to guide revision of the

    initial model.

  • 236.
    Fahlgren, Maria
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Mats
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Geometriska begrepp och metoder i historien: Exemplen area och klassiska konstruktioner2019Report (Refereed)
  • 237.
    Fahlgren, Maria
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Brunström, Mats
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    How the word 'mathematical' influences students’ responses to explanation tasks in a dynamic mathematics software environment2018In: Proceedings of the Fifth ERME Topic Conference (ETC 5) on Mathematics Education in the Digital Age (MEDA) / [ed] Hans-Georg Weigand, Alison Clark-Wilson, Ana Donevska-Todorova, Eleonora Faggiano, Niels Grønbæk, Jana Trgalova, Copenhagen, Denmark: University of Copenhagen , 2018, p. 83-90Conference paper (Refereed)
    Abstract [en]

    Task design is a central issue in mathematics education, not least in relation to digital technology. This paper reports how a smal lbut significant change in wording affects students’ explanatory responses. The study is comparative and involves 229 10th grade students working on tasks designed for a dynamic mathematics software environment. The findings indicate that inclusion of the word ‘mathematical’ prompted students to use algebraic symbols and algebraic arguments, to a higher degree.

  • 238.
    Fahlgren, Maria
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Brunström, Mats
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Using slider tools to explore and validate2015In: CERME9 Proceedings of the Ninth Congress of the European Society for Research in Mathematics Education, 2015Conference paper (Refereed)
  • 239.
    Fairhurst, Gorry
    et al.
    University of Aberdeen, UK..
    Jones, Tom
    University of Aberdeen, UK..
    Bozakov, Zdravko
    Dell EMC, Ireland.
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Damjanovic, Dragana
    Mozilla.
    Eckert, Toerless
    CISCO.
    Evensen, Kristian Riktor
    Celerway.
    Grinnemo, Karl-Johan
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Fosselie Hansen, Audun
    Celerway.
    Khademi, Naeem
    University of Oslo, Norway.
    Mangiante, Simon
    Dell EMC.
    McManus, Patrick
    Mozilla.
    Papastergiou, Giorgos
    Simula.
    Ros, David
    Simula.
    Tüxen, Michael
    FH Münster, Germany.
    Vyncke, Eric
    CISCO.
    Welzl, Michael
    University of Oslo, Norway.
    Deliverable D1.1 - NEAT Architecture2016Report (Refereed)
    Abstract [en]

    Ossification of the Internet transport-layer architecture is a significant barrier to innovation of the Internet. Such innovation is desirable for many reasons. Current applications often need to implement their own mechanisms to receive the transport service they need, but many do not have the breadth of adapting to all possible network characteristics. An updated transport architecture can do much to make the Internet more flexible and extensible. New ground-breaking services often require different or updated transport protocols, could benefit from better signalling between application and network, or desire a more flexible choice of which network path is used for which traffic. This document therefore proposes a new transport architecture. Such architecture lowers the barrier to service innovation by proposing a “transport system”, the NEAT System, that can leverage the rich set of available transport protocols. It paves the way for an architectural change of the Internet where new transport-layer services can seamlessly be integrated and quickly made available, minimising deployment difficulties, and allowing Internet innovators to take advantage of them wherever possible. The document provides a survey of the state-of-the-art to identify the architectural obstacles to, and opportunities for, evolution of the transport layer. It also details a set of general requirements for a new transport architecture. This new architecture is motivated by a set of use-cases, followed by a description of the NEAT architecture for a transport system, designed to permit applications to select appropriate transports based on their needs and the available transport services.

  • 240.
    Fazio, Maria
    et al.
    Univ Messina, Comp Sci, Messina, Italy.
    Ranjan, Rajiv
    Newcastle University.
    Girolami, Michele
    Italian Natl Council Res, Rome, Italy.
    Taheri, Javid
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Dustdar, Schahram
    TU Wien, Computer Science.
    Villari, Massimo
    Univ Messina, Comp Sci, Messina, Italy.
    A Note on the Convergence of IoT, Edge, and Cloud Computing in Smart Cities2018In: IEEE Cloud Computing, ISSN 2325-6095, Vol. 5, no 5, p. 22-24Article in journal (Refereed)
    Abstract [en]

    The purpose of the special issue is to cover all aspects of design and implementation, as well as deployment and evaluation of solutions aimed at the osmotic convergence of IoT, edge, and cloud computing, with specific reference to the smart cities application scenario.

  • 241.
    Ferme, Vincenzo
    et al.
    USI Lugano, Switzerland.
    Lenhard, Jörg
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Harrer, Simon
    University of Bamberg, Germany.
    Geiger, Matthias
    University of Bamberg, Germany.
    Pautasso, Cesare
    Workflow Management Systems Benchmarking: Unfulfilled Expectations and Lessons Learned2017In: PROCEEDINGS OF THE 2017 IEEE/ACM 39TH INTERNATIONAL CONFERENCE ON SOFTWARE ENGINEERING COMPANION (ICSE-C 2017), IEEE, 2017, p. 379-381Conference paper (Refereed)
    Abstract [en]

    Workflow Management Systems (WfMSs) are a type of middleware that enables the execution of automated business processes. Users rely on WfMSs to construct flexible and easily maintainable software systems. Significant effort has been invested into standardising languages for business processes execution, with standards such as the Web Services Business Process Execution Language 2.0 or the Business Process Model and Notation 2.0. Standardisation aims at avoiding vendor lockin and enabling WfMS users to compare different systems. The reality is that, despite standardisation efforts, different independent research initiatives show that objectively comparing WfMSs is still challenging. As a result, WfMS users are likely to discover unfulfilled expectations while evaluating and using these systems. In this work, we discuss the findings of two research initiatives dealing with WfMSs benchmarking, presenting unfulfilled expectations and lessons learned concerning WfMSs' usability, reliability, and portability. Our goal is to provide advice for practitioners implementing or planning to use WfMSs.

  • 242.
    Fernström, Mikael
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Utvecklas modelleringsförmågan nu?: Elevers potentiella utveckling i att modellera inom en specifik modelleringsmodul anpassad för kursen Matematik 5 på gymnasiet.2019Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Mathematical modelling is one of the competences students will have the possibility to develop in upper secondary school. However, it is not entirely obvious among teachers what modelling really means and it is questionable if the learning activities that are being used in relation to modelling education today really are effective. This study focuses on the students’ potential development within a series of lessons, a so-called modelling module, adapted for the course Mathematics 5 in upper secondary school. The students’ potential development is studied based on their involvement in the various sub-processes that are considered to be the modelling process as a hole. The result indicates that the modelling module involves students in all of these sub-processes. At the same time, the results show this is not self-evident and some of the subprocesses seem to be harder to involve the students in than others.

  • 243. Fida, Mah-Rukh
    et al.
    Kousias, Konstantinos
    Lutu, Andra
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Alay, Ozgu
    Brunström, Anna
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Argyriou, Antonios
    FLEX-MONROE: A unified platform for experiments under controlled and operational LTE settings2017In: WiNTECH 2017 Proceedings of the 11th Workshop on Wireless Network Testbeds, Experimental evaluation & CHaracterization, Association for Computing Machinery (ACM), 2017, p. 1-8Conference paper (Refereed)
    Abstract [en]

    This paper presents FLEX-MONROE, a unique platform that facilitates achieving a thorough understanding of LTE networks, one that captures the status of current operational MBB networks and that also enables LTE performance improvements by allowing experimentation in an environment with controllable LTE parameters. Using this platform, we propose to investigate how variations in the LTE network parameters influence the network characteristics, which, in turn, translate to application performance metrics that represent the end-user experience. We argue that the FLEX-MONROE platform is crucial to understand, validate and ultimately improve how current operational MBB networks perform, towards providing guidelines for designing future 5G architectures. Furthermore, understanding the effects of low-level tweaks in network parameters in the LTE infrastructure on the application performance is critical to provide guidelines on how to improve the application performance in the current but also future MBB networks

  • 244.
    Fida, Mah-Rukh
    et al.
    University of Edinburgh, UK.
    Kousias, Konstantinos
    Simula Research Laboratory, Norway.
    Lutu, Andra
    Simula Research Laboratory, Norway.
    Rajiullah, Mohammad
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Alay, Özgü
    Simula Research Laboratory, Norway.
    Brunström, Anna
    Karlstad University, Faculty of Economic Sciences, Communication and IT, Centre for HumanIT. Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Argyriou, Antonios
    University of Thessaly, Greece.
    Demo: experimentation in controlled and operational LTE settings with FLEX-MONROE2017In: Proceedings of the 11th Workshop on Wireless Network Testbeds, Experimental evaluation & Characterization WiNTECH '17, Association for Computing Machinery (ACM), 2017, p. 93-94Conference paper (Refereed)
    Abstract [en]

    This demo paper presents FLEX-MONROE, a platform that facilitates better understanding of current LTE Mobile Broadband(MBB) networks and enables performance improvementsby allowing experimentation with controllable LTE parameters. The platform enables investigating impact oflow-level network parameter tweaks in LTE infrastructure onthe application performance. We argue that FLEX-MONROEis crucial to provide guidelines on improving application performance both in the current and future MBB networks

  • 245.
    Fischer, Andreas
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013). ] Deggendorf Inst Technol, Elect Engn Media Tech & Comp Sci, Deggendorf, Germany.
    Generating Random Service Function Chain Embedding Problems2017In: 2017 IEEE Conference On Network Function Virtualization And Software Defined Networks (Nfv-Sdn), IEEE, 2017, p. 79-84Chapter in book (Other academic)
    Abstract [en]

    The combination of Software Defined Networking (SDN) and Network Function Virtualization (NFV) promises to provide highly flexible and configurable network infrastructures. This relies, however, on an efficient assignment of the respective Service Function Chain (SFC). This is related to Virtual Network Embedding (VNE), where algorithms are devised to provide such an assignment. To evaluate and compare the efficiency of such algorithms, well-designed embedding problems have to be generated. This paper presents a new mechanism for generating embedding problems: Problems are generated from a given set of SFCs such that each generated problem is known in advance to have an optimal solution. Experimenters can use this approach to investigate specific properties of embedding algorithms. The approach, thereby, facilitates more detailed evaluation.

  • 246.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Anonymity2018In: Encyclopedia of Database Systems / [ed] Ling Liu och M. Tamer Özsu, New York, NY: Springer, 2018, 2, p. 111-112Chapter in book (Refereed)
  • 247.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Privacy-enhancing Technologies2018In: Encyclopedia of Database Systems / [ed] Ling Liu och M. Tamer Özsu, New York, NY: Springer, 2018, 2Chapter in book (Refereed)
  • 248.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Pseudonymity2018In: Encyclopedia of Database Systems / [ed] Ling Liu och M. Tamer Özsu, New York, NY: Springer, 2018, 2, p. 2932-2933Chapter in book (Refereed)
  • 249.
    Fischer-Hübner, Simone
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science (from 2013).
    Unobservability2018In: Encyclopedia of Database Systems / [ed] Ling Liu och M. Tamer Özsu, New York, NY: Springer, 2018, 2, p. 4344-4345Chapter in book (Refereed)
  • 250.
    Fischer-Hübner, Simone
    et al.
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Angulo, Julio
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Karegar, Farzaneh
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Pulls, Tobias
    Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Mathematics and Computer Science.
    Transparency, Privacy and Trust: Technology for Tracking and Controlling my Data Disclosures – Does this work?2016In: Proceedings of the 10th IFIPTM Conference 2016: Trust Management X / [ed] Sheikh Mahbub Habib, Julita Vassileva, Sjouke Mauw, Max Mühlhäuser, Heidelberg: Springer Berlin/Heidelberg, 2016Conference paper (Refereed)
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