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  • 1.
    Aarts, Marcel
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Using Kinect to interact with presentation software2013Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Imagination Studios is a company specialized in motion capturing and animation. Part of their daily business is working at trade shows where they have a booth to keep close contact with existing customers and also to find new ones. However, usually only two to three people will be working at the booth, and frequently, these people will be in meetings with potential customers. During a time like this, nobody is free to attend to other people checking out the booth. This can result in a potential loss of a new customer. This project seeks a way to alleviate that problem.The idea behind this project was to create an application that trade show visitors can interact with in a playful and innovative way while also giving them a feel of what Imagination Studios is all about while looking for information about the company. To do this it was decided to let users interact with the system by using a Microsoft Kinect. The Kinect allows for easy implementation of a user interface based on motion capturing while also being very cost effective. A new user interface was to be designed as well, without copying already existing solutions and without simply expanding a traditional UI with new elements. To achieve this several design sketches were made, and the most interesting ones were then turned into storyboards. These were then used to decide on the final design, which was then elaborated on by use of video sketches and a collage in Adobe Photoshop.Several tools were used during the actual implementation. For the actual visualization and graphical design, the Unreal Engine 3 in combination with UDK was decided upon. To connect Kinect and Unreal Engine 3, a third party addon called NIUI which makes use of the open source SDK OpenNI was used. For ease of debugging and programming in Unrealscript, the programming language used by the Unreal Engine 3, an addon for Microsoft Visual Studio 2010 called nFringe (Pixel Mine, Inc., 2010) was used.

  • 2.
    Abbas, M.
    et al.
    University Pretoria, South Africa.
    De La Sen, M.
    University of the Basque Country, Spain.
    Nazir, Talat
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Common Fixed Points of Generalized Rational Type Cocyclic Mappings in Multiplicative Metric Spaces2015Inngår i: Discrete dynamics in nature and society, ISSN 1026-0226, E-ISSN 1607-887X, Vol. 2015, artikkel-id 532725Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to present fixed point result of mappings satisfying a generalized rational contractive condition in the setup of multiplicative metric spaces. As an application, we obtain a common fixed point of a pair of weakly compatible mappings. Some common fixed point results of pair of rational contractive types mappings involved in cocyclic representation of a nonempty subset of a multiplicative metric space are also obtained. Some examples are presented to support the results proved herein. Our results generalize and extend various results in the existing literature.

  • 3.
    Abbas, M.
    et al.
    Ton Duc Thang University, Ho Chi Minh City, Viet Nam.
    Nazir, Talat
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Popović, B.
    University of Kragujevac, Serbia.
    Radenović, S.
    University of Belgrade, Belgrade.
    On Weakly Commuting Set-Valued Mappings on a Domain of Sets Endowed with Directed Graph2017Inngår i: Results in Mathematics, ISSN 1422-6383, Vol. 71, nr 3-4, s. 1277-1295Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to present coincidence and common fixed point results of set-valued mappings satisfying certain generalized graphic F-contractive conditions on a family of sets endowed with a graph. It is worth mentioning that these results are obtained without appealing to any form of continuity of mappings involved herein. Some examples are presented to support the results proved in this paper. Our results unify, generalize and extend various comparable results in the existing literature. © 2016, Springer International Publishing.

  • 4.
    Abbas, Mujahid
    et al.
    Ton Duc Thang Univ, Ho Chi Minh City, Vietnam..
    Nazir, Talat
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Lampert, Tatjana Aleksic
    Fac Sci, Dept Math, Radoja Domanovica 12, Kragujevac 34000, Serbia.
    Radenovic, Stojan
    State Univ Novi Pazar, Serbia..
    Common fixed points of set-valued F-contraction mappings on domain of sets endowed with directed graph2017Inngår i: Computational and Applied Mathemathics, ISSN 0101-8205, Vol. 36, nr 4, s. 1607-1622Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to present common fixed point results of set-valued graphic F-contraction mappings on a family of sets endowed with a graph. Some examples are presented to support the results proved herein. Our results unify, generalize and extend various results in the existing literature.

  • 5.
    Abbaspour Asadollah, Sara
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Daniel, Sundmark
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Eldh, S.
    Ericsson AB, Stockholm, Sweden.
    Hansson, Hans
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Concurrency bugs in open source software: a case study2017Inngår i: Journal of Internet Services and Applications, ISSN 1867-4828, Vol. 8, nr 1, artikkel-id 4Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Concurrent programming puts demands on software debugging and testing, as concurrent software may exhibit problems not present in sequential software, e.g., deadlocks and race conditions. In aiming to increase efficiency and effectiveness of debugging and bug-fixing for concurrent software, a deep understanding of concurrency bugs, their frequency and fixing-times would be helpful. Similarly, to design effective tools and techniques for testing and debugging concurrent software, understanding the differences between non-concurrency and concurrency bugs in real-word software would be useful. This paper presents an empirical study focusing on understanding the differences and similarities between concurrency bugs and other bugs, as well as the differences among various concurrency bug types in terms of their severity and their fixing time, and reproducibility. Our basis is a comprehensive analysis of bug reports covering several generations of five open source software projects. The analysis involves a total of 11860 bug reports from the last decade, including 351 reports related to concurrency bugs. We found that concurrency bugs are different from other bugs in terms of their fixing time and severity while they are similar in terms of reproducibility. Our findings shed light on concurrency bugs and could thereby influence future design and development of concurrent software, their debugging and testing, as well as related tools.

  • 6.
    Abdullah, Syed Md Jakaria
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Virtual Clustered-based Multiprocessor Scheduling in Linux Kernel2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Recent advancements of multiprocessor architectures have led to increasing use of multiprocessors in real-time embedded systems. The two most popular real-time scheduling approaches in multiprocessors are global and partitioned scheduling. Cluster based multiprocessor scheduling can be seen as a hybrid approach combining benefits of both partitioned and global scheduling. Virtual clustering further enhances it by providing dynamic cluster resource allocation duringrun-time and applying hierarchical scheduling to ensure temporal isolation between different software components. Over the years, the study of virtual clustered-based multiprocessor scheduling has been limited to theoretical analysis. In this thesis, we implemented a Virtual-Clustered Hierarchical Scheduling Framework (VC-HSF) in Linux without modifying the base Linux kernel. This work includes complete design, implementation and experimentation of this framework in a multiprocessor platform. Our main contributions are twofold: (i) to the best of our knowledge, our work is the first implementation of any virtual-clustered real-time multiprocessor scheduling in an operating system, (ii) our design and implementation gives practical insights about challenges of implementing any virtual-clustered algorithms for real-time scheduling.

  • 7.
    Abdulle, Assyr
    et al.
    École polytechnique fédérale de Lausanne, Switzerland.
    Arjmand, Doghonay
    École polytechnique fédérale de Lausanne, Switzerland.
    Paganoni, Edoardo
    École polytechnique fédérale de Lausanne, Switzerland.
    Exponential decay of the resonance error in numerical homogenization via parabolic and elliptic cell problems2019Inngår i: Comptes rendus. Mathematique, ISSN 1631-073X, E-ISSN 1778-3569, Vol. 357, nr 6, s. 545-551Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents two new approaches for finding the homogenized coefficients of multiscale elliptic PDEs. Standard approaches for computing the homogenized coefficients suffer from the so-called resonance error, originating from a mismatch between the true and the computational boundary conditions. Our new methods, based on solutions of parabolic and elliptic cell problems, result in an exponential decay of the resonance error.

  • 8.
    Abdumuminov, Shuhrat
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation.
    Esteky, David Emanuel
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation.
    Black-Litterman Model: Practical Asset Allocation Model Beyond Traditional Mean-Variance2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This paper consolidates and compares the applicability and practicality of Black-Litterman model versus traditional Markowitz Mean-Variance model. Although well-known model such as Mean-Variance is academically sound and popular, it is rarely used among asset managers due to its deficiencies. To put the discussion into context we shed light on the improvement made by Fisher Black and Robert Litterman by putting the performance and practicality of both Black- Litterman and Markowitz Mean-Variance models into test. We will illustrate detailed mathematical derivations of how the models are constructed and bring clarity and profound understanding of the intuition behind the models. We generate two different portfolios, composing data from 10-Swedish equities over the course of 10-year period and respectively select 30-days Swedish Treasury Bill as a risk-free rate. The resulting portfolios orientate our discussion towards the better comparison of the performance and applicability of these two models and we will theoretically and geometrically illustrate the differences. Finally, based on extracted results of the performance of both models we demonstrate the superiority and practicality of Black-Litterman model, which in our particular case outperform traditional Mean- Variance model.

  • 9.
    Abed Jaser, Zaid
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Al-Braichi, Osamah Haitham Sabhan
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Measuring Test Coverage in Embedded Software Development Branches2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Most of the hardware products today, especially those that people interact with, are controlled by software. There are many devices with inbuilt software which many people do not bother to notice. Software may be critical in terms of strict quality requirements due to failures which enable risks of endangering the production and more importantly the lives of people. The testing team of Westermo Network Technologies AB faced a challenge with not being able to identify the coverage of tested cases in software. Identifying the coverage of total executed test cases enables the possibility of knowing the potential future quality of a software. By reaching such a stage a software will likely not suffer from failures due to higher quality, therefore the lives of people and the production at stake will not get harmed. The essential problem is that test cases are both tested and skipped, which makes it more difficult for the company to identify what has been actually tested and skipped. The purpose of this thesis is to identify and calculate the coverage of test cases, the process was mainly to understand the essence in the identification of executed test cases. The ethical aspect of putting people's lives at stake is what inspired us to investigate software failures. Software is typically tested before a release, therefore our investigation was to research testing process of software. When investigating test result over many days and test systems we developed a coverage calculator system which helps Westermo to decide and determine the release of tested software, either the software test result is acceptable for a release or not.

  • 10.
    Abedini, Ayda
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation.
    Halm, Martina
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation.
    Att vara eller att icke vara rädd för programmering: En kvalitativ studie om några lärares attityd till programmering och införandet av programmering som centralt innehåll i teknikämnet i läroplanen.2018Independent thesis Advanced level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med denna studie var att få en inblick i några lärares attityd till programmering och införandet av programmering som centralt innehåll i läroplanen. Studien är inriktad inom teknikämnet i mellanstadiet då programmering är aktuellt från och med 2018 i läroplanen. Genom intervjuer med några lärare har vi kommit fram till att majoriteten ställer sig positivt till införandet av programmering i kursplanen. De lärare som ställde sig positivt till detta hade även en del erfarenhet kring programmering. En grund till den positiva attityden är att lärarna har framtiden i åtanke då det kommer krävas mer kunskaper inom digitala verktyg och programmering.

  • 11.
    Abedini, M.
    et al.
    Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran.
    Ahmadzadeh, Farzaneh
    Mälardalens högskola, Akademin för innovation, design och teknik, Innovation och produktrealisering.
    Noorossana, R.
    Department of Industrial Engineering, Iran University of Science and Technology, Tehran, Iran.
    Customer credit scoring using a hybrid data mining approach2016Inngår i: Kybernetes, ISSN 0368-492X, E-ISSN 1758-7883, Vol. 45, nr 10, s. 1576-1588Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Purpose: A crucial decision in financial services is how to classify credit or loan applicants into good and bad applicants. The purpose of this paper is to propose a four-stage hybrid data mining approach to support the decision-making process. Design/methodology/approach: The approach is inspired by the bagging ensemble learning method and proposes a new voting method, namely two-level majority voting in the last stage. First some training subsets are generated. Then some different base classifiers are tuned and afterward some ensemble methods are applied to strengthen tuned classifiers. Finally, two-level majority voting schemes help the approach to achieve more accuracy. Findings: A comparison of results shows the proposed model outperforms powerful single classifiers such as multilayer perceptron (MLP), support vector machine, logistic regression (LR). In addition, it is more accurate than ensemble learning methods such as bagging-LR or rotation forest (RF)-MLP. The model outperforms single classifiers in terms of type I and II errors; it is close to some ensemble approaches such as bagging-LR and RF-MLP but fails to outperform them in terms of type I and II errors. Moreover, majority voting in the final stage provides more reliable results. Practical implications: The study concludes the approach would be beneficial for banks, credit card companies and other credit provider organisations. Originality/value: A novel four stages hybrid approach inspired by bagging ensemble method proposed. Moreover the two-level majority voting in two different schemes in the last stage provides more accuracy. An integrated evaluation criterion for classification errors provides an enhanced insight for error comparisons.

  • 12.
    Abelli, Björn
    Mälardalens högskola, Ekonomihögskolan.
    Directing and Enacting the Information System2007Inngår i: Advances in Information Systems Development: New Methods and Practice for the Networked Society, Volume 2, Issue PART 2, 2007, s. 13-23Konferansepaper (Fagfellevurdert)
  • 13.
    Abelli, Björn
    Mälardalens högskola, Ekonomihögskolan.
    Enacting the e-Society2006Inngår i: Proceedings of the IADIS International Conference e-Society 2006, 2006, s. 285-298Konferansepaper (Fagfellevurdert)
  • 14.
    Abelli, Björn
    Mälardalens högskola, Ekonomihögskolan.
    Programmeringens grunder - med exempel i C#2004Bok (Annet (populærvitenskap, debatt, mm))
    Abstract [en]

    Detta är en lärobok i grundläggande programmering. Den fokuserar på att lära ut det som är gemensamt för de flesta programmeringsspråk – de grundläggande elementen och programkonstruktionerna och hur dessa relaterar till varandra, oberoende av språket. Vilket språk programmet skrivs i måste vara underordnat den uppgift programmet skall lösa. Boken går därför igenom grunderna i strukturerad programmering och visar otaliga exempel i såväl flödesdiagram, strukturdiagram, pseudokod som i källkod. I slutet av boken finns kapitel som går igenom grunderna även i objektorienterad programmering.

    Boken tonar ner inlärningen av ett specifikt programmeringsspråk, men i slutändan måste program ändå skrivas i något språk. Exemplen är skrivna i C# som har slagit igenom som ett praktiskt programmeringsspråk på mycket kort tid och redan börjat göra sitt intåg i högskolekurser i programmering.

    I första hand är boken avsedd för nybörjare i programmering på högskolenivå, som vill lära sig programmeringens grunder.

  • 15.
    Abelli, Björn
    et al.
    Mälardalens högskola, Ekonomihögskolan.
    Révay, Péter
    Mälardalens högskola, Ekonomihögskolan.
    To Be or Not To Be Computer Based2004Inngår i: Proceedings of microCAD 2004, 2004, s. 1-8Konferansepaper (Fagfellevurdert)
  • 16.
    Abola, Benard
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, School of Physical Sciences, Makerere University, Kampala, Uganda.
    Biganda, Pitos
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, College of Natural and Applied Sciences, University of Dar es Salaam,Tanzania.
    Engström, Christopher
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Anguzu, Collins
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, Makerere University, Kampala, Uganda.
    Mango, John Magero
    Department of Mathematics, Makerere University, Kampala, Uganda.
    Kakuba, Gudwin
    Department of Mathematics, Makerere University, Kampala, Uganda.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    A Variant of Updating Page Rank in Evolving Tree graphs2019Inngår i: Proceedings of 18th Applied Stochastic Models and Data Analysis International Conference with the Demographics 2019 Workshop, Florence, Italy: 11-14 June, 2019 / [ed] Christos H. Skiadas, ISAST: International Society for the Advancement of Science and Technology , 2019, s. 31-49Konferansepaper (Fagfellevurdert)
    Abstract [en]

    PageRank update refers to the process of computing new PageRank values after change(s) (addition or removal of links/vertices) has occurred in real life networks. The purpose of the updating is to avoid recalculating the values from scratch. To efficiently carry out the update, we consider PageRank as the expected number of visits to target vertex if multiple random walks are performed, starting at each vertex once and weighing each of these walks by a weight value. Hence, it might be looked at as updating non-normalised PageRank. In the proposed approach, a scaled adjacency matrix is sequentially updated after every change and the levels of the vertices being updated as well. This enables sets of internal and sink vertices dependent on their roots or parents, thus vector-vector product can be performed sequentially since there are no infinite steps from one vertex to the other.

  • 17.
    Abola, Benard
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, School of Physical Sciences, Makerere University, Kampala, Uganda.
    Biganda, Pitos
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, College of Natural and Applied Sciences, University of Dar es Salaam,Tanzania.
    Engström, Christopher
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Mango, J. M.
    Department of Mathematics, School of Physical Sciences, Makerere University, Kampala, Uganda.
    Kakuba, G.
    Department of Mathematics, School of Physical Sciences, Makerere University, Kampala, Uganda.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    PageRank in evolving tree graphs2018Inngår i: Stochastic Processes and Applications: SPAS2017, Västerås and Stockholm, Sweden, October 4-6, 2017 / [ed] Sergei Silvestrov, Anatoliy Malyarenko, Milica Rančić, Springer, 2018, Vol. 271, s. 375-390Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    In this article, we study how PageRank can be updated in an evolving tree graph. We are interested in finding how ranks of the graph can be updated simultaneously and effectively using previous ranks without resorting to iterative methods such as the Jacobi or Power method. We demonstrate and discuss how PageRank can be updated when a leaf is added to a tree, at least one leaf is added to a vertex with at least one outgoing edge, an edge added to vertices at the same level and forward edge is added in a tree graph. The results of this paper provide new insights and applications of standard partitioning of vertices of the graph into levels using breadth-first search algorithm. Then, one determines PageRanks as the expected numbers of random walk starting from any vertex in the graph. We noted that time complexity of the proposed method is linear, which is quite good. Also, it is important to point out that the types of vertex play essential role in updating of PageRank.

  • 18.
    Abola, Benard
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, School of Physical Sciences, Makerere University, Kampala, Uganda.
    Biganda, Pitos
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, College of Natural and Applied Sciences, University of Dar es Salaam,Tanzania.
    Engström, Christopher
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Evaluation of Stopping Criteria for Ranks in Solving Linear Systems2019Inngår i: Data Analysis and Applications 1: Clustering and Regression, Modeling‐estimating, Forecasting and Data Mining, Volume 2 / [ed] Christos H. Skiadas, James R. Bozeman, John Wiley & Sons, 2019, Chapter 10, s. 137-152Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    Bioinformatics, internet search engines (web pages) and social networks are some of the examples with large and high sparsity matrices. For some of these systems, only the actual ranks of the solution vector is interesting rather than the vector itself. In this case, it is desirable that the stopping criterion reflects the error in ranks rather than the residual vector that might have a lower convergence. This chapter evaluates stopping criteria on Jacobi, successive over relaxation (SOR) and power series iterative schemes. Numerical experiments were performed and results show that Kendall's correlation coefficient gives good stopping criterion of ranks for linear system of equations. The chapter focuses on the termination criterion as means of obtaining good ranks. It outlines some studies carried out on stopping criteria in solving the linear system.

  • 19.
    Abola, Benard
    et al.
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, School of Physical Sciences, Makerere University, Kampala, Uganda.
    Biganda, Pitos
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Department of Mathematics, College of Natural and Applied Sciences, University of Dar es Salaam,Tanzania.
    Silvestrov, Dmitrii
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik. Stockholm University, Sweden.
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.
    Mango, John
    Department of Mathematics, Makerere University, Kampala, Uganda.
    Kakuba, Gudwin
    Department of Mathematics, Makerere University, Kampala, Uganda.
    Nonlinearly  Perturbed Markov Chains  and  Information Networks2019Inngår i: Proceedings of 18th Applied Stochastic Models and Data Analysis International Conference with the Demographics 2019 Workshop, Florence, Italy: 11-14 June, 2019 / [ed] Christos H. Skiadas, ISAST: International Society for the Advancement of Science and Technology , 2019, s. 51-79Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper is devoted to studies of perturbed Markov chains commonly used for description of information networks. In such models, the matrix of transition probabilities for the corresponding Markov chain is usually regularised by adding  a special damping matrix multiplied by a small damping (perturbation) parameter ε. In this paper, we present results of the detailed perturbation analysis of Markov chains with damping component and numerical experiments supporting and illustrating the results of this perturbation analysis.

  • 20.
    Abrahamsson, Henrik
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Internet Traffic Management2008Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 21.
    Abrahamsson, Henrik
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Network overload avoidance by traffic engineering and content caching2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The Internet traffic volume continues to grow at a great rate, now driven by video and TV distribution. For network operators it is important to avoid congestion in the network, and to meet service level agreements with their customers.  This thesis presents work on two methods operators can use to reduce links loads in their networks: traffic engineering and content caching.

    This thesis studies access patterns for TV and video and the potential for caching.  The investigation is done both using simulation and by analysis of logs from a large TV-on-Demand system over four months.

    The results show that there is a small set of programs that account for a large fraction of the requests and that a comparatively small local cache can be used to significantly reduce the peak link loads during prime time. The investigation also demonstrates how the popularity of programs changes over time and shows that the access pattern in a TV-on-Demand system very much depends on the content type.

    For traffic engineering the objective is to avoid congestion in the network and to make better use of available resources by adapting the routing to the current traffic situation. The main challenge for traffic engineering in IP networks is to cope with the dynamics of Internet traffic demands.

    This thesis proposes L-balanced routings that route the traffic on the shortest paths possible but make sure that no link is utilised to more than a given level L. L-balanced routing gives efficient routing of traffic and controlled spare capacity to handle unpredictable changes in traffic.  We present an L-balanced routing algorithm and a heuristic search method for finding L-balanced weight settings for the legacy routing protocols OSPF and IS-IS. We show that the search and the resulting weight settings work well in real network scenarios.

  • 22.
    Abrahamsson, Henrik
    et al.
    Swedish Institute of Computer Science, Kista, Sweden.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Caching for IPTV distribution with time-shift2013Inngår i: 2013 International Conference on Computing, Networking and Communications, ICNC 2013, IEEE , 2013, s. 916-921Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Today video and TV distribution dominate Internet traffic and the increasing demand for high-bandwidth multimedia services puts pressure on Internet service providers. In this paper we simulate TV distribution with time-shift and investigate the effect of introducing a local cache close to the viewers. We study what impact TV program popularity, program set size, cache replacement policy and other factors have on the caching efficiency. The simulation results show that introducing a local cache close to the viewers significantly reduces the network load from TV-on-Demand services. By caching 4% of the program volume we can decrease the peak load during prime time by almost 50%. We also show that the TV program type and how program popularity changes over time can have a big influence on cache hit ratios and the resulting link loads

  • 23.
    Abrahamsson, Henrik
    et al.
    Swedish Institute of Computer Science.
    Björkman, Mats
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Simulation of IPTV caching strategies2010Inngår i: Proceedings of the 2010 International Symposium on Performance Evaluation of Computer and Telecommunication Systems, 2010, s. 187-193Konferansepaper (Fagfellevurdert)
    Abstract [en]

    IPTV, where television is distributed over the Internet Protocol in a single operator network, has become popular and widespread. Many telecom and broadband companies have become TV providers and distribute TV channels using multicast over their backbone networks. IPTV also means an evolution to time-shifted television where viewers now often can choose to watch the programs at any time. However, distributing individual TV streams to each viewer requires a lot of bandwidth and is a big challenge for TV operators. In this paper we present an empirical IPTV workload model, simulate IPTV distribution with time-shift, and show that local caching can limit the bandwidth requirements significantly.

  • 24.
    Abrahamsson, Henrik
    et al.
    Swedish Institute of Computer Science, Kista, Sweden.
    Nordmark, Mattias
    TeliaSonera AB, Stockholm, Sweden .
    Program popularity and viewer behaviour in a large TV-on-Demand system2012Inngår i: IMC '12 Proceedings of the 2012 ACM conference on Internet measurement conference, New York: ACM , 2012, s. 199-210Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Today increasingly large volumes of TV and video are distributed over IP-networks and over the Internet. It is therefore essential for traffic and cache management to understand TV program popularity and access patterns in real networks.

    In this paper we study access patterns in a large TV-on-Demand system over four months. We study user behaviour and program popularity and its impact on caching. The demand varies a lot in daily and weekly cycles. There are large peaks in demand, especially on Friday and Saturday evenings, that need to be handled.

    We see that the cacheability, the share of requests that are not first-time requests, is very high. Furthermore, there is a small set of programs that account for a large fraction of the requests. We also find that the share of requests for the top most popular programs grows during prime time, and the change rate among them decreases. This is important for caching. The cache hit ratio increases during prime time when the demand is the highest, and aching makes the biggest difference when it matters most.

    We also study the popularity (in terms of number of requests and rank) of individual programs and how that changes over time. Also, we see that the type of programs offered determines what the access pattern will look like.

  • 25. Abramov, V.
    et al.
    Paal, E.Tallinn University of Technology.Silvestrov, Sergei D.Mälardalens högskola, Akademin för utbildning, kultur och kommunikation, Utbildningsvetenskap och Matematik.Stolin, A.Chalmers University of Techology.
    Proceedings of the 3rd Baltic-Nordic Workshop “Algebra, Geometry, and Mathematical Physics”2008Konferanseproceedings (Fagfellevurdert)
  • 26. Abramov, Viktor
    et al.
    Paal, Eugen
    Silvestrov, Sergei
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation.
    Stolin, Alexander
    Preface [Special issue devoted to the 4th Baltic-Nordic Workshop “Algebra, Geometry and Mathematical Physics”]2010Inngår i: Proceedings of the Estonian Academy of Sciences, ISSN 1736-6046, E-ISSN 1736-7530, Vol. 59, nr 4Artikkel i tidsskrift (Fagfellevurdert)
  • 27.
    Acheampong, Archibold Nana
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation.
    Analyzing the "True" Delta, Gamma and Vega of European Swaptions in Black-76 and Bachelier Models Using Python2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Option pricing models such as the Black-76, Bachelier and Stochastic Alpha Beta Rho (SABR) models define delta, gamma and vega using the forward rate as the underlying instrument. In terms of options on swaps, this underlying instrument is the forward swap rate, which is the market fixed rate on the swap. This work employs the Black-76 and Bachelier models to determine delta, gamma and vega of a European swaption, but rather uses the swap value as the underlying instrument. We use data in our implementation and the work is done in the python programming language. 

    Our results yielded relatively higher absolute delta values than those implied by the conventional Black-76 and Bachelier models. This means that our method yields relatively higher sensitivity of the swaption value to small changes in underlying asset value. It also means higher trading volumes of the swap contract to hedge against small changes in the value of the underlying swap using our method. It was also observed from our gamma values that both our method and the conventional Black-76 and Bachelier models can provide better sensitivities, relative to each other, to big changes in the underlying swap value. This, however, depends on the choice of strike rate. Further, our work produced comparatively lower absolute vega values, hence, lower sensitivity to changing implied volatility. To be able to use volatility values in both the normal and log-normal sense, we converted from normal to log-normal volatilities. This was achieved numerically using the Newton Raphson method implemented in python. 

    Changes in swap value and volatility were mimicked using basis point additions and subtractions of certain parameter values, specifically, floating rates, forward rate and volatility values. Each basis point adjustment in the necessary parameter yielded a different delta, gamma or vega value. Since the swap value or volatility can change multiple times within a specific time period, it was observed that there can exist a series of delta, gamma and vega values within a specific period of time.

  • 28.
    Acheampong, Isaac
    Mälardalens högskola, Institutionen för matematik och fysik.
    Java Applet for the Pricing of Exotic Options by Monte-Carlo Simulations in a Levy market with Stochastic Volatility2006Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
  • 29.
    Achrenius, William
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Bergman Törnkvist, Martin
    Mälardalens högskola, Akademin för innovation, design och teknik.
    GRAPH GENERATION ALGORITHMS FOR THE GRADE DECISION CANVAS2018Independent thesis Basic level (degree of Bachelor), 12 hpOppgave
    Abstract [en]

    Development in the field of software architecture, from the early days in the mid-80’s, has been significant. From purely technical descriptions to decision based architectural knowledge, software architecture has seen fundamental changes to its methodologies and techniques. Architectural knowledge is a resource that is managed and stored by companies, this resource is valuable because it can be reused and analysed to improve future development. Companies today are interested in the reasoning behind the software architecture. This reasoning is mainly formulated through the architectural decisions made during development. For architectural decisions to be easier to analyse they need to be stored in a way that enables use of common analytical tools so that comparisons between decisions are consistent and relevant. Additionally, it is also important to have enough data, which leads us to the problem that, preferably, all the individual architectural knowledge cases must be structured and stored. To do this we present a tool that uses graph generation algorithms to generate architectural knowledge as graphs based on an architectural decision canvas called GRADE. This enables multiple decision cases to be encoded through graphs that can be used to analyse relationships and balances between different architectural knowledge elements represented through nodes and edges within a graph.

  • 30.
    Achuthan, Krishnashree
    et al.
    Amrita Vishwa Vidyapeetham, Amrita Ctr Cybersecur Syst & Networks, Kollam, Kerala, India..
    Ramesh, Maneesha V.
    Amrita Vishwa Vidyapeetham, Amrita Ctr Int Programs, Kollam, Kerala, India..
    Punnekkat, Sasikumar
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Raman, Raghu
    Amrita Vishwa Vidyapeetham, Ctr Res Adv Technol Educ, Kollam, Kerala, India..
    Internationalizing Engineering Education With Phased Study Programs: India-European Experience2014Inngår i: 2014 IEEE FRONTIERS IN EDUCATION CONFERENCE (FIE), IEEE , 2014, s. 295-301Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Most of the critical challenges seen in the past decades have impacted citizens in a global way. Given shrinking resources, educationists find preparing students for the global market place a formidable challenge. Hence exposing students to multi-lateral educational initiatives are critical to their growth, understanding and future contributions. This paper focuses on European Union's Erasmus Mundus programs, involving academic cooperation amongst international universities in engineering programs. A phased undergraduate engineering program with multiple specializations is analyzed within this context. Based on their performance at the end of first phase, selected students were provided opportunities using scholarship to pursue completion of their degree requirements at various European universities. This paper will elaborate the impact of differing pedagogical interventions, language and cultural differences amongst these countries on students in diverse engineering disciplines. The data presented is based on on the feedback analysis from Eramus Mundus students (N = 121) that underwent the mobility programs. The findings have given important insights into the structure of the initiative and implications for academia and education policy makers for internationalizing engineering education. These included considering digital interventions such as MOOCs (Massive Open Online Courses) and Virtual Laboratory (VL) initiatives for systemic reorganization of engineering education.

  • 31.
    ADENIYA, Abdel Tariq
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation.
    MARGIN VALUATION ADJUSTMENT of an INTEREST RATE SWAP2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    After the last financial crisis, regulators started to strengthen the measures to reduce the risk on the financial market by requiring margin to be posted. In addition to the Variation Margin that reflects the daily change in market value of the contracts, Initial Margin has to be posted to compensate the fluctuation of the collateral value. The Margin Valuation Adjustment (MVA) represents the funding price of the initial margin that has to be calculated. The numerical calculation of the MVA is a real challenge as it requires to run a Monte Carlo simulation inside another Monte Carlo simulation. However, alternative formula could be used to approximate the result of the MVA. This thesis highlights the essential notion about the MVA and the available tools to calculate its value.

  • 32.
    Adobah-Otchey, Daniel
    Mälardalens högskola, Akademin för utbildning, kultur och kommunikation.
    Risk-Efficient Portfolios; Estimation Error In Essence2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis primarily looks at estimation error problems and other related issues arising in connection with portfolio optimization. With some available assets, a portfolio program or optimizer seeks to distribute a fixed amount of capital among these available assets to optimize some cost function. In this regard, Markowitz portfolio selection basis defines the variance of the portfolio return to being that of the portfolio risk and tries to find an allocation that reduces or minimizes the risk subject to a target mean or expected return. Should the mean return vector and the covariance matrix of returns for the underlying assets be known, the Markowitz problem is said to have a closed-form solution.

    In practice, however, an estimation is made from historical data for unknown expected returns and the covariance matrix of the returns, and this brings into the domain several problems such as estimation problems and renders the Markowitz theory impracticable in real-life portfolio applications. Estimators necessary to remedy these problems would be made bare to show how possible it is to tackle such issues.

    In the concept demonstration sections, the analysis starts with the price data of 40 stocks and the S\&P index. The efficient frontier is introduced and used to show how the estimators take effect.

    Finally, implementation is made possible using the R Programming Language to demonstrate the necessary concepts with the conclusion presented at the end.

  • 33.
    Adolfsson, Catarina
    Mälardalens högskola, Institutionen för matematik och fysik.
    Lärares syn på lässvaga elever inom matematik2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med detta arbete är att ta reda på hur lärarna upplever att lässvaga elever påverkas av sina lässvårigheter inom matematiken samt hur lärarna hanterar de problem som uppstår för att hjälpa eleven. Jag har valt den kvalitativa arbetsmetoden med semistrukturerade intervjufrågor. Resultatet visar att svag läsförmåga påverkar eleven inom matematiken men också inom andra ämnen. Inom matematiken påverkas eleven särskilt vid lästal samt vid problemlösning om eleven lämnas ensam med en text som den inte klarar av att läsa eller tyda. För att stödja eleven kan läraren eller någon annan läsa texten eller så arbetar eleverna i grupp där samarbetet mot resultatet är viktigast, inte att kunna läsa texten. Slutsatsen visar att eleven aldrig bör lämnas ensam med en text som den inte förstår, då eleven utestängs från den matematiska processen och det matematiska tänkandet.

  • 34.
    Afshar, Sara
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Lock-Based Resource Sharing in Real-Time Multiprocessor Platforms2014Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Embedded systems are typically resource constrained, i.e., resources such as processors, I/O devices, shared buffers or shared memory can be limited for tasks in the system. Therefore, techniques that enable an efficient usage of such resources are of great importance.

    In the industry, typically large and complex software systems are divided into smaller parts (applications) where each part is developed independently. Migration towards multiprocessor platforms has become inevitable from an industrial perspective. Due to such migration and to efficient use of system resources, these applications eventually may be integrated on a shared multiprocessor platform. In order to facilitate the integration phase of the applications on a shared platform, the timing and resource requirements of each application can be provided in an interface when the application is developed. The system integrator can benefit from such provided information in the interface of each application to ease the integration process. In this thesis, we have provided the resource and timing requirements of each application in their interfaces for applications that may need several processors to be allocated on when they are developed.

    Although many scheduling techniques have been studied for multiprocessor systems, these techniques are usually based on the assumption that tasks are independent, i.e. do not share resources other than the processors. This assumption is typically not true. In this thesis, we provide an extension to such systems to handle sharing of resources other than processor among tasks. Two traditional approaches exist for multiprocessor systems to schedule tasks on processors. A recent scheduling approach for multiprocessors has combined the two traditional approaches and achieved a hybrid more efficient approach compared to the two previous one. Due to the complex nature of this scheduling approach the conventional approaches for resource sharing could not be used straight forwardly. In this thesis, we have modified resource sharing approaches such that they can be used in such hybrid scheduling systems. A second concern is that enabling resource sharing in the systems can cause unpredictable delays and variations in response time of tasks which can degrade system performance. Therefore, it is of great significance to improve the resource handling techniques to reduce the effect of imposed delays caused by resource sharing in a multiprocessor platform. In this thesis we have proposed alternative techniques for resource handling that can improve system performance for special setups.

  • 35.
    Afshar, Sara
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bril, R. J.
    Technische Universiteit Eindhoven, Eindhoven, Netherlands .
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Flexible spin-lock model for resource sharing in multiprocessor real-time systems2014Inngår i: Proc. IEEE Int. Symp. Ind. Embedded Syst., SIES, 2014, s. 41-51Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Various approaches can be utilized upon resource locking for mutually exclusive resource access in multiprocessor platforms. So far two conventional approaches exist for dealing with tasks that are blocked on a global resource in a multi-processor platform. Either the blocked task performs a busy wait, i.e. spins, at the highest priority level until the resource is released, or it is suspended. Although both approaches provide mutually exclusive access to resources, they can introduce long blocking delays to tasks, which may be unacceptable for many industrial applications. In this paper, we propose a general spin-based model for resource sharing in multiprocessor platforms in which the priority of the blocked tasks during spinning can be selected arbitrarily. Moreover, we provide the analysis for two selected spin-lock priorities and we show by means of a general comparison as well as specific examples that these solutions may provide a better performance for higher priority tasks.

  • 36.
    Afshar, Sara
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bril, Reinder J.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Technische Universiteit Eindhoven, Eindhoven, Netherlands.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Resource Sharing Under Global Scheduling with Partial Processor Bandwidth2015Inngår i: 2015 10th IEEE International Symposium on Industrial Embedded Systems, SIES 2015 - Proceedings, 2015, s. 195-206Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Resource efficient approaches are of great importance for resource constrained embedded systems. In this paper, we present an approach targeting systems where tasks of a critical application are partitioned on a multi-core platform and by using resource reservation techniques, the remaining bandwidth capacity on each core is utilized for one or a set of non-critical application(s). To provide a resource efficient solution and to exploit the potential parallelism of the extra applications on the multi-core processor, global scheduling is used to schedule the tasks of the non-critical applications. Recently a specific instantiation of such a system has been studied where tasks do not share resources other than the processor. In this paper, we enable semaphore-based resource sharing among tasks within critical and non-critical applications using a suspension-based synchronization protocol. Tasks of non-critical applications have partial access to the processor bandwidth. The paper provides the systems schedulability analysis where blocking due to resource sharing is bounded. Further, we perform experimental evaluations under balanced and unbalanced allocation of tasks of a critical application to cores.

  • 37.
    Afshar, Sara
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    J. Bril, Reinder
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Per Processor Spin-Lock Priority for Partitioned Multiprocessor Real-Time Systems2014Rapport (Annet vitenskapelig)
    Abstract [en]

    Two traditional approaches exist for a task that is blocked on a global resource; a task either performs a non-preemptive busy wait, i.e., spins, or suspends and releases the processor. Previously, we have shown that both approaches can be viewed as spinning either at the highest priority HP or at the lowest priority on the processor LP, respectively. Based on this view, previously we have generalized a task's blocking behavioral model, as spinning at any arbitrary priority level. In this paper, we focus on a particular class of spin-lock protocols from the introduced flexible spin-lock model where spinning is performed at a priority equal to or higher than the highest local ceiling of the global resources accessed on a processor referred to as CP spin-lock approach. In this paper, we assume that all tasks of a specific processor are spinning on the same priority level. Given this class and assumption, we show that there exists a spin-lock protocol in this range that dominates the classic spin-lock protocol which tasks spin on highest priority level (HP). However we show that this new approach is incomparable with the CP spin-lock approach. Moreover, we show that there may exist an intermediate spin-lock approach between the priority used by CP spin-lock approach and the new introduced spin-lock approach that can make a task set schedulable when those two cannot. We provide an extensive evaluation results comparing the HP, CP and the new proposed approach.

  • 38.
    Afshar, Sara
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Behnam, Moris
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    J. Bril, Reinder
    Technische Universiteit Eindhoven, Eindhoven, The Netherlands.
    Nolte, Thomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Per Processor Spin-Lock Priority for Partitioned Multiprocessor Real-Time Systems2017Inngår i: Leibniz Transactions on Embedded Systems, ISSN 2199-2002, nr 2Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Two traditional approaches exist for a task that is blocked on a global resource; a task either performs a non-preemptive busy wait, i.e., spins, or suspends and releases the processor. Previously, we have shown that both approaches can be viewed as spinning either at the highest priority HP or at the lowest priority on the processor LP, respectively. Based on this view, previously we have generalized a task's blocking behavioral model, as spinning at any arbitrary priority level. In this paper, we focus on a particular class of spin-lock protocols from the introduced flexible spin-lock model where spinning is performed at a priority equal to or higher than the highest local ceiling of the global resources accessed on a processor referred to as CP spin-lock approach. In this paper, we assume that all tasks of a specific processor are spinning on the same priority level. Given this class and assumption, we show that there exists a spin-lock protocol in this range that dominates the classic spin-lock protocol which tasks spin on highest priority level (HP). However we show that this new approach is incomparable with the CP spin-lock approach. Moreover, we show that there may exist an intermediate spin-lock approach between the priority used by CP spin-lock approach and the new introduced spin-lock approach that can make a task set schedulable when those two cannot. We provide an extensive evaluation results comparing the HP, CP and the new proposed approach.

  • 39.
    Afzal, Wasif
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Bruneliere, H.
    IMT Atlantique – LS2N (CNRS) – ARMINES, France.
    Di Ruscio, D.
    Università degli Studi dell'Aquila - DISIM | Center of Excellence DEWS, Italy.
    Sadovykh, A.
    Softeam, France.
    Mazzini, S.
    Intecs, Italy.
    Cariou, E.
    Université de Pau et des Pays de l'Adour, LIUPPA, France.
    Truscan, D.
    Åbo Akademi University, Finland.
    Cabot, J.
    ICREA, Spain.
    Gómez, A.
    Internet Interdisciplinary Institute (IN3), Universitat Oberta de Catalunya (UOC), Spain.
    Gorroñogoitia, J.
    ATOS, Spain.
    Pomante, L.
    Università degli Studi dell'Aquila - DISIM | Center of Excellence DEWS, Italy.
    Smrz, P.
    Brno University of Technology, Czech Republic.
    The MegaM@Rt2 ECSEL project: MegaModelling at Runtime – Scalable model-based framework for continuous development and runtime validation of complex systems2018Inngår i: Microprocessors and microsystems, ISSN 0141-9331, E-ISSN 1872-9436, Vol. 61, s. 86-95Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A major challenge for the European electronic industry is to enhance productivity by ensuring quality of development, integration and maintenance while reducing the associated costs. Model-Driven Engineering (MDE) principles and techniques have already shown promising capabilities, but they still need to scale up to support real-world scenarios implied by the full deployment and use of complex electronic components and systems. Moreover, maintaining efficient traceability, integration, and communication between two fundamental system life cycle phases (design time and runtime) is another challenge requiring the scalability of MDE. This paper presents an overview of the ECSEL 1 project entitled “MegaModelling at runtime – Scalable model-based framework for continuous development and runtime validation of complex systems” (MegaM@Rt2), whose aim is to address the above mentioned challenges facing MDE. Driven by both large and small industrial enterprises, with the support of research partners and technology providers, MegaM@Rt2 aims to deliver a framework of tools and methods for: 1) system engineering/design and continuous development, 2) related runtime analysis and 3) global models and traceability management. Diverse industrial use cases (covering strategic domains such as aeronautics, railway, construction and telecommunications) will integrate and demonstrate the validity of the MegaM@Rt2 solution. This paper provides an overview of the MegaM@Rt2 project with respect to its approach, mission, objectives as well as to its implementation details. It further introduces the consortium as well as describes the work packages and few already produced deliverables.

  • 40.
    Afzal, Wasif
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Caporuscio, M.
    Linnaeus University, Sweden.
    Conboy, H.
    University of Massachusetts Amherst, MA, United States.
    Di Marco, A.
    University of l'Aquila, Italy.
    Duchien, D. L.
    University of Lille, France.
    Pérez, D.
    University of British Columbia, Canada.
    Seceleanu, C.
    Kyushu University, Japan.
    Shahbazian, A.
    University of California, Berkeley, CA, United States.
    Spalazzese, R.
    Microsoft, WA, United States.
    Tivoli, M.
    Florida State University, FL, United States.
    Vasilescu, B.
    University College Dublin and Lero, Ireland.
    Washizaki, H
    Mälardalens högskola.
    Weyns, D.
    University of Southern California, CA, United States.
    Pasquale, L.
    Malmö University, Sweden.
    Nistor, A.
    Malmö University, Sweden.
    Muşlu, K.
    Waseda University, Japan.
    Kamei, Y.
    Waseda University, Japan.
    Hanam, Q.
    Carnegie Mellon University, PA, United States.
    Ying, A. T. T.
    Katholieke Universiteit Leuven, Belgium.
    Program committee for icse 2018 posters track2018Inngår i: Proceedings / International Conference of Software Engineering, ISSN 0270-5257, E-ISSN 1558-1225, Vol. Part F137351Artikkel i tidsskrift (Fagfellevurdert)
  • 41.
    Afzal, Wasif
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ghazi, Nauman
    Blekinge Institute of Technolog.
    Itkonen, Juha
    Aalto University, Espoo, Finland.
    Torkar, Richard
    Chalmers University of Technology.
    Andrews, Anneliese
    University of Denver, USA.
    Bhatti, Khurram
    Blekinge Institute of Technolog.
    An experiment on the effectiveness and efficiency of exploratory testing2015Inngår i: Journal of Empirical Software Engineering, ISSN 1382-3256, E-ISSN 1573-7616, Vol. 20, nr 3, s. 844-878Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The exploratory testing (ET) approach is commonly applied in industry, but lacks scientific research. The scientific community needs quantitative results on the performance of ET taken from realistic experimental settings. The objective of this paper is to quantify the effectiveness and efficiency of ET vs. testing with documented test cases (test case based testing, TCT). We performed four controlled experiments where a total of 24 practitioners and 46 students performed manual functional testing using ET and TCT. We measured the number of identified defects in the 90-minute testing sessions, the detection difficulty, severity and types of the detected defects, and the number of false defect reports. The results show that ET found a significantly greater number of defects. ET also found significantly more defects of varying levels of difficulty, types and severity levels. However, the two testing approaches did not differ significantly in terms of the number of false defect reports submitted. We conclude that ET was more efficient than TCT in our experiment. ET was also more effective than TCT when detection difficulty, type of defects and severity levels are considered. The two approaches are comparable when it comes to the number of false defect reports submitted.

  • 42.
    Afzal, Wasif
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. Bahria University, Islamabad, Pakistan .
    Torkar, Richard
    Blekinge Institute of Technology, Karlskrona, Sweden; Chalmers University of Technology, Sweden.
    Towards benchmarking feature subset selection methods for software fault prediction2016Inngår i: Computational Intelligence and Quantitative Software Engineering / [ed] Witold Pedrycz, Giancarlo Succi and Alberto Sillitti, Springer-Verlag , 2016, s. 33-58Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Despite the general acceptance that software engineering datasets often contain noisy, irrele- vant or redundant variables, very few benchmark studies of feature subset selection (FSS) methods on real-life data from software projects have been conducted. This paper provides an empirical comparison of state-of-the-art FSS methods: information gain attribute ranking (IG); Relief (RLF); principal com- ponent analysis (PCA); correlation-based feature selection (CFS); consistency-based subset evaluation (CNS); wrapper subset evaluation (WRP); and an evolutionary computation method, genetic program- ming (GP), on five fault prediction datasets from the PROMISE data repository. For all the datasets, the area under the receiver operating characteristic curve—the AUC value averaged over 10-fold cross- validation runs—was calculated for each FSS method-dataset combination before and after FSS. Two diverse learning algorithms, C4.5 and na ??ve Bayes (NB) are used to test the attribute sets given by each FSS method. The results show that although there are no statistically significant differences between the AUC values for the different FSS methods for both C4.5 and NB, a smaller set of FSS methods (IG, RLF, GP) consistently select fewer attributes without degrading classification accuracy. We conclude that in general, FSS is beneficial as it helps improve classification accuracy of NB and C4.5. There is no single best FSS method for all datasets but IG, RLF and GP consistently select fewer attributes without degrading classification accuracy within statistically significant boundaries.

  • 43.
    Agbamuche, Joy
    Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling.
    How does the alignment of IT to business strategy affect the organisation of the IT function?2008Oppgave
    Abstract [en]

    Date: 2008-06-04

    Purpose: The primary goal of this research is to describe the IT function and examine how its alignment to an organisations strategy affects the way it is organised.

    Method: The chosen method was a purely theoretical examination with the use of the case study of Windham International as primary resource and secondary resources such as book and literature review used for the thesis.

    Research Questions: How does the alignment of IT to business strategy affect the organisation of the IT function?

    Conclusion: One of the findings was that a few researchers seem to suggest that the centralized mode of organising IT was symbolic of the past, while outsourcing and decentralization are the modern approach to organising IT. Wyndham International shows the opposite, after the introduction of the CIO in 2002, centralization was the chosen mode of organisation because that was what would best fit the new strategic approach of the organisation. Insourcing rather than outsourcing proved to be a winning formula.

  • 44.
    Ahl, Linda
    Mälardalens högskola, Institutionen för matematik och fysik.
    Problemlösning, kontext och kompetens2007Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med arbetet är att undersöka hur matematiklärarstudenter ska introducera problemlösning för sina elever och vad som påverkar studenternas tolkningar av problem. Jag har även undersökt vilka kompetenser studenterna anser att en matematiklärare behöver ha för att genomföra en framgångsrik undervisning i matematik genom problemlösning. I undersökningen diskuterar tre grupper med matematiklärarstudenter hur de ska introducera ett problem för eleverna och vilka komprtenser de anser att en matematiklärare behöver ha för att undervisa i matematik genom problemlösning. Resultaten visar att studenterna har olika strategier för att introducera problemlösning för eleverna och att studenternas tolkningar av problemet påverkar introduktionen. Studenterna gör olika tolkningar av problemet beroende av i vilken kontext de tolkar problemet. De har ingen enhetlig bild av vilka kompetenser som krävs av en matematiklärare, för att genomföra en undervisning som svarar mot skolverkets mål.

  • 45.
    Ahlberg, Carl
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Embedded high-resolution stereo-vision of high frame-rate and low latency through FPGA-acceleration2020Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Autonomous agents rely on information from the surrounding environment to act upon. In the array of sensors available, the image sensor is perhaps the most versatile, allowing for detection of colour, size, shape, and depth. For the latter, in a dynamic environment, assuming no a priori knowledge, stereo vision is a commonly adopted technique. How to interpret images, and extract relevant information, is referred to as computer vision. Computer vision, and specifically stereo-vision algorithms, are complex and computationally expensive, already considering a single stereo pair, with results that are, in terms of accuracy, qualitatively difficult to compare. Adding to the challenge is a continuous stream of images, of a high frame rate, and the race of ever increasing image resolutions. In the context of autonomous agents, considerations regarding real-time requirements, embedded/resource limited processing platforms, power consumption, and physical size, further add up to an unarguably challenging problem.

    This thesis aims to achieve embedded high-resolution stereo-vision of high frame-rate and low latency, by approaching the problem from two different angles, hardware and algorithmic development, in a symbiotic relationship. The first contributions of the thesis are the GIMME and GIMME2 embedded vision platforms, which offer hardware accelerated processing through FGPAs, specifically targeting stereo vision, contrary to available COTS systems at the time. The second contribution, toward stereo vision algorithms, is twofold. Firstly, the problem of scalability and the associated disparity range is addressed by proposing a segment-based stereo algorithm. In segment space, matching is independent of image scale, and similarly, disparity range is measured in terms of segments, indicating relatively few hypotheses to cover the entire range of the scene. Secondly, more in line with the conventional stereo correspondence for FPGAs, the Census Transform (CT) has been identified as a recurring cost metric. This thesis proposes an optimisation of the CT through a Genetic Algorithm (GA) - the Genetic Algorithm Census Transform (GACT). The GACT shows promising results for benchmark datasets, compared to established CT methods, while being resource efficient.

  • 46.
    Ahlberg, Carl
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Leon, Miguel
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekstrand, Fredrik
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Ekström, Mikael
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system.
    Unbounded Sparse Census Transform using Genetic Algorithm2019Inngår i: 2019 IEEE WINTER CONFERENCE ON APPLICATIONS OF COMPUTER VISION (WACV), IEEE , 2019, s. 1616-1625Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Census Transform (CT) is a well proven method for stereo vision that provides robust matching, with respect to object boundaries, outliers and radiometric distortion, at a low computational cost. Recent CT methods propose patterns for pixel comparison and sparsity, to increase matching accuracy and reduce resource requirements. However, these methods are bounded with respect to symmetry and/or edge length. In this paper, a Genetic algorithm (GA) is applied to find a new and powerful CT method. The proposed method, Genetic Algorithm Census Transform (GACT), is compared with the established CT methods, showing better results for benchmarking datasets. Additional experiments have been performed to study the search space and the correlation between training and evaluation data.

  • 47.
    Ahlström, Louise
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Informationsmaterial till Europaskolan2008Oppgave
    Abstract [sv]

    Rapporten är resultatet av mitt examensarbete i Textdesign vid Mälardalens högskola. På uppdrag av Europaskolan i Strängnäs har ett informationsmaterial utvecklats och resulterat i en broschyr. Målgruppen är elever i årskurs nio som ska söka gymnasieutbildning. Rapporten beskriver det tillvägagångssätt som använts vid

    framtagningen av det nya informationsmaterialet. Med utgångspunkt i begreppen läsligt, läsbart och läsvärt har text, bild och layout utformats för att skapa en informativ och målgruppsanpassad broschyr. Metoder som använts är komparation, textanalys och litteraturstudier. Utprovningsmetoden som tillämpats är enskilda intervjuer med elever

    på Europaskolan. Slutsatser som dragits är att behovet av designad information ökar i dagens mediebrus och att sändarens budskap till mottagaren måste genomgå en hermeneutisk process.

  • 48.
    Ahmadi, Dara
    et al.
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Panin, Vadim
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Skissamarbete på digitala plattformar2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Datorstött kooperativt arbete (hädanefter förkortat CSCW efter engelskans Computer-Supported Cooperative Work) är när ett system underlättar datorbaserat arbete i grupp på distans och söker lämplig teknik för att uppnå optimal effektivitet i gruppens arbetsprocess. Ett exempel på ett sådant system kan vara skissamarbete på digitala plattformar. Inom interaktionsdesign finns ett intresse för skissamarbete på digitala plattformar. Vi har därför valt att inom ramen för vårt arbete undersöka om skissamarbete på digitala plattformar är ett effektivt arbetssätt för designers och vilka funktioner en sådan plattform bör ha. För att få svar på våra frågor har vi valt att skapa en Android samt en Webbapplikation för skissamarbete. I våra applikationer har vi beaktat designers önskemål gällande funktioner. Applikationerna användes i en undersökning för att kunna grundligt analysera hur designers skissamarbetar på digitala plattformar. Resultatet har visat att skissamarbete på digitala plattformar är ett smidigt och mobilt arbetssätt som medför aktiva diskussioner, skapar nya idéer och bättre lösningar, bidrar till kunskapsöverföring, bättre arbetsmiljö och samspel mellan designers.

  • 49.
    Ahmed, Mobyen Uddin
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A case-based multi-modal clinical system for stress management2010Licentiatavhandling, monografi (Annet vitenskapelig)
    Abstract [en]

    A difficult issue in stress management is to use biomedical sensor signal in the diagnosis and treatment of stress. Clinicians often make their diagnosis and decision based on manual inspection of physiological signals such as, ECG, heart rate, finger temperature etc. However, the complexity associated with manual analysis and interpretation of the signals makes it difficult even for experienced clinicians. Today the diagnosis and decision is largely dependent on how experienced the clinician is interpreting the measurements.  A computer-aided decision support system for diagnosis and treatment of stress would enable a more objective and consistent diagnosis and decisions.

    A challenge in the field of medicine is the accuracy of the system, it is essential that the clinician is able to judge the accuracy of the suggested solutions. Case-based reasoning systems for medical applications are increasingly multi-purpose and multi-modal, using a variety of different methods and techniques to meet the challenges of the medical domain. This research work covers the development of an intelligent clinical decision support system for diagnosis, classification and treatment in stress management. The system uses a finger temperature sensor and the variation in the finger temperature is one of the key features in the system. Several artificial intelligence techniques have been investigated to enable a more reliable and efficient diagnosis and treatment of stress such as case-based reasoning, textual information retrieval, rule-based reasoning, and fuzzy logic. Functionalities and the performance of the system have been validated by implementing a research prototype based on close collaboration with an expert in stress. The case base of the implemented system has been initiated with 53 reference cases classified by an experienced clinician. A case study also shows that the system provides results close to a human expert. The experimental results suggest that such a system is valuable both for less experienced clinicians and for experts where the system may function as a second option.

  • 50.
    Ahmed, Mobyen Uddin
    Mälardalens högskola, Akademin för innovation, design och teknik.
    A Multimodal Approach for Clinical Diagnosis and Treatment2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    A computer-aided Clinical Decision Support System (CDSS) for diagnosis and treatment often plays a vital role and brings essential benefits for clinicians. Such a CDSS could function as an expert for a less experienced clinician or as a second option/opinion of an experienced clinician to their decision making task. Nevertheless, it has been a real challenge to design and develop such a functional system where accuracy of the system performance is an important issue.

    This research work focuses on development of intelligent CDSS based on a multimodal approach for diagnosis, classification and treatment in medical domains i.e. stress and post-operative pain management domains. Several Artificial Intelligence (AI) techniques such as Case-Based Reasoning (CBR), textual Information Retrieval (IR), Rule-Based Reasoning (RBR), Fuzzy Logic and clustering approaches have been investigated in this thesis work.

    Patient’s data i.e. their stress and pain related information are collected from complex data sources for instance, finger temperature measurements through sensor signals, pain measurements using a Numerical Visual Analogue Scale (NVAS), patient’s information from text and multiple choice questionnaires. The proposed approach considers multimedia data management to be able to use them in CDSSs for both the domains.

    The functionalities and performance of the systems have been evaluated based on close collaboration with experts and clinicians of the domains. In stress management, 68 measurements from 46 subjects and 1572 patients’ cases out of ≈4000 in post-operative pain have been used to design, develop and validate the systems. In the stress management domain, besides the 68 measurement cases, three trainees and one senior clinician also have been involved in order to conduct the experimental work. The result from the evaluation shows that the system reaches a level of performance close to the expert and better than the senior and trainee clinicians. Thus, the proposed CDSS could be used as an expert for a less experienced clinician (i.e. trainee) or as a second option/opinion for an experienced clinician (i.e. senior) to their decision making process in stress management. In post-operative pain treatment, the CDSS retrieves and presents most similar cases (e.g. both rare and regular) with their outcomes to assist physicians. Moreover, an automatic approach is presented in order to identify rare cases and 18% of cases from the whole cases library i.e. 276 out of 1572 are identified as rare cases by the approach. Again, among the rare cases (i.e. 276), around 57.25% of the cases are classified as ‘unusually bad’ i.e. the average pain outcome value is greater or equal to 5 on the NVAS scale 0 to 10. Identification of rear cases is an important part of the PAIN OUT project and can be used to improve the quality of individual pain treatment.

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