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  • 51.
    Andersson, Filip
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Fault Diagnosis in Distributed Simulation Systems over Wide Area Networks using Active Probing2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The domain of distributed simulation is growing rapidly. This growth leads to larger and more complex supporting network architectures with high requirements on availability and reliability. For this purpose, efficient fault-monitoring is required. This work is an attempt to evaluate the viability of an Active probing approach in a distributed simulation system in a wide area network setting. In addition, some effort was directed towards building the probing-software with future extensions in mind. The Active probing approach was implemented and tested against certain performance requirements in a simulated environment. It was concluded that the approach is viable for detecting the health of the network components. However, additional research is required to draw a conclusion about the viability in more complicated scenarios that depend on more than the responsiveness of the nodes. The extensibility of the implemented software was evaluated with the QMOOD-metric and not deemed particularly extensible.

  • 52.
    Andersson, Henrik
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Knowledge management and throughput optimization in large-scale software development2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Large-scale software development companies delivering market-driven products have introduced agile methodologies as the way of working to a big extent. Even though there are many benefits with an agile way of working, problems occur when scaling agile because of the increased complexity. One explicit problem area is to evolve deep product knowledge, which is a domain specific knowledge that cannot be developed anywhere else but at the specific workplace. This research aims to identify impediments for developing domain specific knowledge and provide solutions to overcome these challenges in order to optimize knowledge growth and throughput.

    The result of the research shows that impediments occur in four different categories, based on a framework for knowledge sharing drivers. These are people-related, task-related, structure-related and technology-related. The challenging element with knowledge growth is to integrate the training into the feature development process, without affecting the feature throughput negatively.

    The research also shows that by increasing the knowledge sharing, the competence level of the whole organization can be increased, and thereby be beneficial from many perspectives, such as feature-throughput and code quality.

  • 53.
    Andersson, Simon
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Energy Consumption of 3G Transmissions for Instant Messaging on Mobile Devices2013Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    A recent surge in the usage of instant messaging (IM) applications on mobile devices has brought the energy efficiency of those applications into the light. We are entering an era where IM applications are changing the message communication on mobile devices, beginning to overtake SMS messages and even phone calls in some cases. Smartphones experience a tremendous increase of data transmissions through wireless interfaces. As illustrated in this work, today's IM applications differ vastly in energy consumption when using the third generation (3G) cellular communication. This thesis focuses on studying the 3G transmission energy footprint of IM applications at the handset level. The energy cost of a common feature used in IM applications that informs that the user is currently typing a response ('typing notify'), is evaluated. The feature is shown to incur a great increase in energy cost compared to the base chat function, ranging from an increase of 43 % to 117 %. The work also proposes a bundle technique that aggregates chat messages over time reducing the energy consumption at the cost of delay for the user. The results show that the bundle technique can save up to 47 % in energy consumption while still keeping the chat function. For the evaluation, conversations collected from a popular IM application are used.

  • 54.
    Andréasson, Dan
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Morja, Daniel
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Rekonstruktion och optimering av laddningstid för en webbsida i Ruby on Rails2015Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Många verksamheter representeras idag på internet i omodern stil vilket kan påverka besökarens uppfattning om verksamheten negativt. I detta arbete har en webbsida rekonstruerats. Webbsidan tillhör en förening med verksamhet inom gaming och esport. Rekonstruktionen är till för att ge besökare en klar bild av vad föreningens huvudverksamhet är och för att integrera streamingtjänsten Twitch för att ge besökare ytterligare en anledning att återbesöka sidan. Dessutom har laddningstiden för startsidan optimerats för att ge bättre besökupplevelse. Med hjälp av Redis och metoden Eager loading visar arbetet hur man kan sänka laddningstiden på en webbsida.

  • 55.
    Aragon, Elena
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Jimenez, Juan M.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Maghazeh, Arian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Rasmusson, Jim
    Sony Mobile Communications, Sweden.
    Bordoloi, Unmesh D.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Pattern matching in OpenCL: GPU vs CPU energy consumption on two mobile chipsets2014In: Proceedings of the International Workshop / OpenCL 2013 & 2014 (IWOCL '14), ACM Digital Library, 2014, Article No. 5- p.Conference paper (Other academic)
    Abstract [en]

    Adaptations of the Aho-Corasick (AC) algorithm on high performance graphics processors (also called GPUs) have garnered increasing attention in recent years. However, no results have been reported regarding their implementations on mobile GPUs. In this paper, we show that implementing a state-of-the-art Aho-Corasick parallel algorithm on a mobile GPU delivers significant speedups. We study a few implementation optimizations some of which may seem counter-intuitive to standard optimizations for high-end GPUs. More importantly, we focus on measuring the energy consumed by different components of the OpenCL application rather than reporting the aggregate. We show that there are considerable energy savings compared to the CPU implementation of the AC algorithm.

  • 56.
    Arman, Sheikh Ali
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    RESTful Mobile Application for Android: Mobile Version of Inspectera Online2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Web service-based mobile applications have become emergent in the recent years. Representational State Transfer (REST) architecture style introduced the concept of Resource Oriented Architecture (ROA), which has been widely used for building applications for all platforms. This master’s thesis designs and develops a Web service-based mobile application for Android platform following the constraints of REST architectural style. It also proposes an authentication model for RESTful applications. The master’s thesis is completed at the company Inspectera HK AB in Norrköping, Sweden. The developed application is called the “Mobile version of Inspectera Online.” 

  • 57.
    Artchounin, Daniel
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Tuning of machine learning algorithms for automatic bug assignment2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In software development projects, bug triage consists mainly of assigning bug reports to software developers or teams (depending on the project). The partial or total automation of this task would have a positive economic impact on many software projects. This thesis introduces a systematic four-step method to find some of the best configurations of several machine learning algorithms intending to solve the automatic bug assignment problem. These four steps are respectively used to select a combination of pre-processing techniques, a bug report representation, a potential feature selection technique and to tune several classifiers. The aforementioned method has been applied on three software projects: 66 066 bug reports of a proprietary project, 24 450 bug reports of Eclipse JDT and 30 358 bug reports of Mozilla Firefox. 619 configurations have been applied and compared on each of these three projects. In production, using the approach introduced in this work on the bug reports of the proprietary project would have increased the accuracy by up to 16.64 percentage points.

  • 58.
    Arvanitaki, Antonia
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Pappas, Nikolaos
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Modeling of a UAV-based Data Collection System2017In: IEEE 22nd International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD), Lund, Sweden, 2017Conference paper (Refereed)
  • 59.
    Arvid, Johnsson
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Analysis of GPU accelerated OpenCL applications on the Intel HD 4600 GPU2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    GPU acceleration is the concept of accelerating the execution speed of an application by running it on the GPU. Researchers and developers have always wanted to achieve greater speed for their applications and GPU acceleration is a very common way of doing so. This has been done a long time for highly graphical applications using powerful dedicated GPUs. However, researchers have become more and more interested in using GPU acceleration on everyday applications. Moreover now a days more or less every computer has some sort of integrated GPU which often is underutilized. The integrated GPUs are not as powerful as dedicated ones but they have other benefits such as a lower power consumption and faster data transfer. Therefore this thesis’ purpose was to examine whether the integrated GPU Intel HD 4600 can be used to accelerate the two applications Image Convolution and sparse matrix vector multiplication (SpMV). This was done by analysing the code from a previous thesis which produced some unexpected results as well as a benchmark from the OpenDwarf’s benchmark suite. The Intel HD 4600 was able to speedup both Image Convolution and SpMV by about two times compared to running them on the Intel i7-4790. However, the SpMV implementation was not well suited for the GPU meaning that the speedup was only observed on ideal input configurations.

  • 60.
    Arvidsson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    3D Visualization Package for OpenModelica2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A 3D representation of a physical phenomena is often a good way to present it. It’s often easier to see an event in an animation rather than just read data tables. The goal of this thesis is to create an application that visualizes a physical simulation in Modelica. This thesis explains how the OMVisualize application was developed. To create the OMVisualize the OpenSceneGraph library was used. The OpenSceneGraph is a 3D package written in C++ that is used in many different applications from game to scientific applications.

  • 61.
    Asani, Golnaz
    et al.
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory.
    Zadegan, Farrokh Ghani
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Ingelsson, Urban
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory.
    Carlsson, Gunnar
    Ericsson, Linköping, Sweden.
    Larsson, Erik
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory.
    Test Scheduling with Constraints for IEEE P1687 (poster)2011In: International Test Conference (ITC11), Anaheim, CA, USA, September 18-23, 2011., 2011Conference paper (Refereed)
  • 62.
    Asghar, Adeel
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Pfeiffer, Andreas
    DLR Institute of System Dynamic and Control, Wessling, Tyskland.
    Palanisamy, Arunkumar
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Mengist, Alachew
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Sjölund, Martin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Pop, Adrian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Fritzson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Automatic Regression Testing of Simulation Models and Concept for Simulation of Connected FMUs in PySimulator2015In: Proceedings of the 11th International Modelica Conference: Versailles, France, September 21-23, 2015 / [ed] Peter Fritzson, Hilding Elmqvist, Linköping, 2015, 671-679 p.Conference paper (Refereed)
    Abstract [en]

    The Modelica and FMI tool ecosystem is growing each year with new tools and methods becoming available. The open Modelica standard promises portability but it is important to ensure that a certain model behaves the same in different Modelica tools or in a different version of the same tool. It is also very important (for model evolution) to check that a new version of the same model produces comparable results. Finally, it is desirable to verify that a model exported in FMU form from a Modelica tool gives exactly the same results as the original model. This paper presents a framework for automatic regression testing as part of PySimulator which provides an efficient and concise way of testing if a model or a range of models behaves in the same way in several tools or versions of a tool by checking that the results produced are essentially identical. The FMI standard has been adopted by many tool vendors and is growing in popularity each year. This paper proposes a concept for building and simulating a system made from connected FMUs generated by different tools. The FMUs for Co-Simulation can be connected together using a GUI. The system model built graphically in this way can be saved for later use or simulated directly inside PySimulator. Active development is going on to support simulation of connected FMUs for Model Exchange.

  • 63.
    Asplund, Mikael
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Model-based Membership Verification in Vehicular Platoons2015In: Proceedings: 2015 45th Annual IEEE/IFIP International Conference on Dependable Systems and Networks Workshops , IEEE Computer Society, 2015, 125-132 p.Conference paper (Refereed)
    Abstract [en]

    Cooperative vehicular systems have the potentialto significantly increase traffic efficiency and safety. However,they also raise the question of to what extent information thatis received from other vehicles can be trusted. In this paperwe present a novel approach for increasing the trustworthinessof cooperative driving through a model-based approach forverifying membership views in vehicular platoons. We define aformal model for platoon membership, cooperative awarenessclaims, and membership verification mechanisms. With the helpof a satisfiability solver, we are able to quantitatively analysethe impact of different system parameters on the verifiability ofreceived information. Our results demonstrate the importance ofcross validating received messages, as well as the surprising diffi-culty in establishing correct membership views despite powerfulverification mechanisms.

  • 64.
    Asplund, Mikael
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Poster: Securing Vehicular Platoon Membership2014In: Proceedings of IEEE Vehicular Networking Conference (VNC), IEEE Computer Society, 2014, 119-120 p.Conference paper (Refereed)
    Abstract [en]

    Vehicular platoons have the potential to bring considerable fuel-savings and increase traffic efficiency. A key component for the next generation platoon systems is a secure membership component which can accommodate membership changes in a dynamic and potentially hostile environment. In this poster paper we analyse the conditions for creating a secure membership protocol which is resilient to attacks and faults in the communication protocols.

  • 65.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, Faculty of Science & Engineering.
    Lövhall, Jakob
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Villani, Emilia
    Auronatics Institute of Technology, Brazil.
    Specification, Implementation and Verification of Dynamic Group Membership for Vehicle Coordination2017In: Dependable Computing (PRDC), 2017 IEEE 22nd Pacific Rim International Symposium on, IEEE, 2017, 321-328 p.Conference paper (Refereed)
    Abstract [en]

    New advanced traffic management solutions with fully or semi-autonomous vehicles that communicate over a wireless interface to coordinate their driving decisions create new challenges in distributed computing. In this paper we address the problem of dynamic group membership in three stages. First, we propose three criteria to specify correctness and performance of the group views created by such algorithms in terms of soundness, completeness and freshness. Second, we develop a group membership protocol tailored for vehicular coordination. Finally, we show through simulation and model-based verification that the protocol does indeed meet the criteria and provide at least 95% perfect group membership views under as adverse conditions as 70% packet loss or very high churn rate.

  • 66.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Analysing Delay-tolerant Networks with Correlated Mobility2012In: Ad-hoc, Mobile, and Wireless Networks: 11th International Conference, ADHOC-NOW 2012, Belgrade, Serbia, July 9-11, 2012. Proceedings / [ed] Xiang-Yang Li, Symeon Papavassiliou, Stefan Ruehrup, Springer , 2012, 83-97 p.Chapter in book (Refereed)
    Abstract [en]

    This book constitutes the refereed proceedings of the 11th International Conference on Ad-hoc, Mobile, and Wireless Networks, ADHOC-NOW 2012 held in Belgrade, Serbia, July 9-11, 2012. The 36 revised full papers presented were carefully reviewed and selected from 76 submissions. The accepted papers cover a wide spectrum of traditional networking topics ranging from routing to the application layer, to localization in various networking environments such as wireless sensor and ad-hoc networks, and give insights in a variety of application areas.

  • 67.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Attitudes and Perceptions of IoT Security in Critical Societal Services2016In: IEEE Access, E-ISSN 2169-3536, Vol. 4, 2130-2138 p.Article in journal (Refereed)
    Abstract [en]

    A quiet revolution that impacts several sectors, ranging over transport, home automation, energy, industrial control, and health services is undergoing with addition of new networked devices leading to enhanced services. In this paper, we aim to identify information security requirements that are common over several (vertical) sectors, and in particular, ones that impact critical societal services, namely, the energy, water, and health management systems. We present the results of an interview-based study where actors in these sectors were asked about their perceptions and attitudes on the security of Internet of Things (IoT). We set these perceptions and attitudes in context through a literature review of IoT security, and relate to current challenges in this area. This paper demonstrates that despite an overall optimistic view on IoT in critical societal services, there is a lack of consensus on risks related to IoT security.

  • 68.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Rapid selection and dissemination of urgent messages over delay-tolerant networks (DTNs)2015In: Advances in Delay-Tolerant Networks (DTNs): Architecture and Enhanced Performance / [ed] J. Rodrigues, Elsevier, 2015, 187-203 p.Chapter in book (Refereed)
    Abstract [en]

    Today many new applications are emerging that take advantage of wireless communication in handheld and embedded devices. Some of these emerging applications, such as information sharing in vehicular systems, have strong requirements for timely message dissemination, even if the network is not always 100% connected. In this chapter we discuss message differentiation mechanisms that can be used in intermittently connected networks to improve delivery and latency properties when messages have a limited time to live in the network. We present a simulation-based study on a large-scale vehicular scenario comparing different prioritisation mechanisms for a partition-tolerant manycast protocol. We show that negative effects of overloads can be significantly reduced by using information within the message about how far it has spread and how much time is remaining.

  • 69.
    Asplund, Mikael
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Worst-case latency of broadcast in intermittently connected networks2012In: International Journal of Ad Hoc and Ubiquitous Computing, ISSN 1743-8225, Vol. 11, no 2-3, 125-138 p.Article in journal (Refereed)
    Abstract [en]

    Worst-case latency is an important characteristic of information dissemination protocols. However, in sparse mobile ad hoc networks where end-to-end connectivity cannot be achieved and store-carry-forward algorithms are needed, such worst-case analyses have not been possible to perform on real mobility traces due to lack of suitable models. We propose a new metric called delay expansion that reflects connectivity and reachability properties of intermittently connected networks. Using the delay expansion, we show how bounds on worst-case latency can be derived for a general class of broadcast protocols and a wide range of real mobility patterns. The paper includes theoretical results that show how worst-case latency can be related with delay expansion for a given mobility scenario, as well as simulations to validate the theoretical model.

  • 70.
    Avdic, Kenan
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    On-chip Pipelined Parallel Mergesort on the Intel Single-Chip Cloud Computer2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    With the advent of mass-market consumer multicore processors, the growing trend in the consumer off-the-shelf general purpose processor industry has moved away from increasing clock frequency as the classical approach for achieving higher performance. This is commonly attributed to the well-known problems of power consumption and heat dissipation with high frequencies and voltage.

    This paradigm shift has prompted research into a relatively new field of "many-core" processors, such as the Intel Single-chip Cloud Computer. The SCC is a concept vehicle, an experimental homogenous architecture employing 48 IA32 cores interconnected by a high-speed communication network.

    As similar multiprocessor systems, such as the Cell Broadband Engine, demonstrate a significantly higher aggregate bandwidth in the interconnect network than in memory, we examine the viability of a pipelined approach to sorting on the Intel SCC. By tailoring an algorithm to the architecture, we investigate whether this is also the case with the SCC and whether employing a pipelining technique alleviates the classical memory bottleneck problem or provides any performance benefits.

    For this purpose, we employ and combine different classic algorithms, most significantly, parallel mergesort and samplesort.

  • 71.
    Avdic, Kenan
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Melot, Nicolas
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Kessler, Christoph
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Keller, Jörg
    FernUniversität in Hagen.
    Pipelined parallel sorting on the Intel SCC2011In: Fourth Swedish Workshop on Multi-Core Computing MCC-2011: November 23-25, 2011, Linköping University, Linköping, Sweden / [ed] Christoph Kessler, Linköping: Linköping University , 2011, Vol. S. 96-101, 96-101 p.Conference paper (Other academic)
    Abstract [en]

    The Single-Chip Cloud Computer (SCC) is an experimental processor created by Intel Labs. It comprises 48 Intel-IA32 cores linked by an on-chip high performance mesh network, as well as four DDR3 memory controllers to access an off-chip main memory. We investigate the adaptation of sorting onto SCC as an algorithm engineering problem. We argue that a combination of pipelined mergesort and sample sort will fit best to SCC's architecture. We also provide a mapping based on integer linear programming to address load balancing and latency considerations. We describe a prototype implementation of our proposai together with preliminary runtime measurements, that indicate the usefulness of this approach. As mergesort can be considered as a representative of the class of streaming applications, the techniques deveioped here should also apply to the other problems in this class, such as many applications for parallel embedded systems, i.e. MPSoC. 

  • 72.
    Azari, Leila
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Domain Specific Modeling Support for ArCon2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One important phase in software development process is to create a design model of the system which follows all the architectural rules. Often the architectural rules are defined by the system architect and the system model is designed by the system designer. The architect defines the rules in a text file where no standard or pattern is followed. Therefore, there is always the risk of violating the architectural rules by the designer. So manual reviews on the system model should be done by the architect to ensure the system model is valid.In order to remove this manual checking which can be erroneous and time consuming ArCon (Architecture Conformance Checker) was developed by Combitech AB. ArCon is a tool which lets the architect define the architectural rules in the format of UML (Unified Modeling Language) models where the elements of the model have different meaning than the standard UML. ArCon can read this model and extract architectural rules from it and check the system model against those rules and then print all the rule violations.ArCon is an open source tool i.e. free for everyone to download and use. Currently, it supports Papyrus as the UML modeling tool. Papyrus is integrated to Eclipse platform and is a general purpose modeling tool. It supports users with all types of UML diagrams and elements.The idea for this thesis work was to implement a new feature for ArCon in order to facilitate the design process for system designers. The feature should provide the system designers only those types of elements which they are permitted to add to a specific fraction of the system model. The list of permitted element types should be extracted from the architecture model where all the architectural rules are defined in advance. This new support in ArCon was named Domain Specific Modeling (DSM) support.To evaluate the effect of DSM support on the system designers performance a few test sessions, called usability tests, were performed. The participants in the test sessions were a representative sample of software designers. After analyzing the data collected from the test sessions, the pros and cons of the new support were discovered. Furthermore, a few new ideas for enhancing DSM support were generated.

  • 73.
    Aziz Abdulla, Parosh
    et al.
    Uppsala University, Sweden.
    Faouzi Atig, Mohamed
    Uppsala University, Sweden.
    Chen, Yu-Fang
    Academic Sinica, Taiwan.
    Holik, Lukas
    Brno University of Technology, Czech Republic.
    Rezine, Ahmed
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Rummer, Philipp
    Uppsala University, Sweden.
    Stenman, Jari
    Uppsala University, Sweden.
    Norn: An SMT Solver for String Constraints2015In: COMPUTER AIDED VERIFICATION, PT I, SPRINGER-VERLAG BERLIN , 2015, Vol. 9206, 462-469 p.Conference paper (Refereed)
    Abstract [en]

    We present version 1.0 of the Norn SMT solver for string constraints. Norn is a solver for an expressive constraint language, including word equations, length constraints, and regular membership queries. As a feature distinguishing Norn from other SMT solvers, Norn is a decision procedure under the assumption of a set of acyclicity conditions on word equations, without any restrictions on the use of regular membership.

  • 74.
    Aziz Abdulla, Parosh
    et al.
    Uppsala University, Sweden.
    Haziza, Frederic
    Uppsala University, Sweden.
    Holik, Lukas
    Uppsala University, Sweden; Brno University of Technology, Czech Republic.
    Jonsson, Bengt
    Uppsala University, Sweden.
    Rezine, Ahmed
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    An integrated specification and verification technique for highly concurrent data structures for highly concurrent data structures2017In: International Journal on Software Tools for Technology Transfer (STTT), ISSN 1433-2779, E-ISSN 1433-2787, Vol. 19, no 5, 549-563 p.Article in journal (Refereed)
    Abstract [en]

    We present a technique for automatically verifying safety properties of concurrent programs, in particular programs that rely on subtle dependencies of local states of different threads, such as lock-free implementations of stacks and queues in an environment without garbage collection. Our technique addresses the joint challenges of infinite-state specifications, an unbounded number of threads, and an unbounded heap managed by explicit memory allocation. Our technique builds on the automata-theoretic approach to model checking, in which a specification is given by an automaton that observes the execution of a program and accepts executions that violate the intended specification. We extend this approach by allowing specifications to be given by a class of infinite-state automata. We show how such automata can be used to specify queues, stacks, and other data structures, by extending a data-independence argument. For verification, we develop a shape analysis, which tracks correlations between pairs of threads, and a novel abstraction to make the analysis practical. We have implemented our method and used it to verify programs, some of which have not been verified by any other automatic method before.

  • 75.
    Banerjee, Abhijeet
    et al.
    National University of Singapore.
    Chong, Lee Kee
    National University of Singapore.
    Chattopadhyay, Sudipta
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Roychoudhury, Abhik
    National University of Singapore.
    Detecting Energy Bugs and Hotspots in Mobile Apps2014In: FSE 2014: Foundations of Software Engineering, Association for Computing Machinery (ACM), 2014, 588-598 p.Conference paper (Refereed)
    Abstract [en]

    Over the recent years, the popularity of smartphones has increased dramatically. This has lead to a widespread availability of smartphone applications. Since smartphones operate on a limited amount of battery power, it is important to develop tools and techniques that aid in energy-efficient application development. Energy inefficiencies in smartphone applications can broadly be categorized into energy hotspots and energy bugs. An energy hotspot can be described as a scenario where executing an application causes the smartphone to consume abnormally high amount of battery power, even though the utilization of its hardware resources is low. In contrast, an energy bug can be described as a scenario where a malfunctioning application prevents the smartphone from becoming idle, even after it has completed execution and there is no user activity. In this paper, we present an automated test generation framework that detects energy hotspots/bugs in Android applications. Our framework systematically generates test inputs that are likely to capture energy hotspots/bugs. Each test input captures a sequence of user interactions (e.g. touches or taps on the smartphone screen) that leads to an energy hotspot/bug in the application. Evaluation with 30 freely-available Android applications from Google Play/F-Droid shows the efficacy of our framework in finding hotspots/bugs. Manual validation of the experimental results shows that our framework reports reasonably low number of false positives. Finally, we show the usage of the generated results by improving the energy-efficiency of some Android applications.

  • 76.
    Beck-Norén, Gustav
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Cross-platform Development for Wearable Devices2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The market for wearable devices is continuously growing and has seen an in- crease in interest and demand this past year, specifically smartwatch devices. With several big players entering and trying to take place in the market the number of devices and platforms grow. This leads to device and software fragmentation like the one seen in the world of smartphones. In this paper I discuss and compare the two smartwatch platforms Android Wear and Apple Watch in terms of possibilities, limitations and differences. Research is done to find cross-platform development possibilities for these platforms. Extensive theoretical background of both APIs is researched and presented. An app for both smartwatch platforms is developed with integration of the WebSocket protocol to function as a remote control for a Video-On-Demand web service. This is done to showcase the cross-platform possibilities and differences of the platforms. As a result the biggest differences are out- lined and a conclusion is made that cross-platform development for these platforms can be challenging but is possible on certain levels. 

  • 77.
    Bengtsson, Tomas
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Testing and Logic Optimization Techniques for Systems on Chip2012Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Today it is possible to integrate more than one billion transistors onto a single chip. This has enabled implementation of complex functionality in hand held gadgets, but handling such complexity is far from trivial. The challenges of handling this complexity are mostly related to the design and testing of the digital components of these chips.

    A number of well-researched disciplines must be employed in the efficient design of large and complex chips. These include utilization of several abstraction levels, design of appropriate architectures, several different classes of optimization methods, and development of testing techniques. This thesis contributes mainly to the areas of design optimization and testing methods.

    In the area of testing this thesis contributes methods for testing of on-chip links connecting different clock domains. This includes testing for defects that introduce unacceptable delay, lead to excessive crosstalk and cause glitches, which can produce errors. We show how pure digital components can be used to detect such defects and how the tests can be scheduled efficiently.

    To manage increasing test complexity, another contribution proposes to raise theabstraction level of fault models from logic level to system level. A set of system level faultmodels for a NoC-switch is proposed and evaluated to demonstrate their potential.

    In the area of design optimization, this thesis focuses primarily on logic optimization. Two contributions for Boolean decomposition are presented. The first one is a fast heuristic algorithm that finds non-disjoint decompositions for Boolean functions. This algorithm operates on a Binary Decision Diagram. The other contribution is a fast algorithm for detecting whether a function is likely to benefit from optimization for architectures with a gate depth of three with an XOR-gate as the third gate.

  • 78.
    Benjamin, Andersson
    Linköping University, Department of Computer and Information Science, Software and Systems.
    En teoretisk och praktisk jämförelse av alternativ till OpenLayers2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Med att de mobila enheterna blir allt mer kraftigare och webbtekniken går allt fortare framåt, så har webbapplikationer börjat blivit ett fullgott alternativ till vanliga nativeapplikationer. Presentera webbkartor med hjälp av ramverket OpenLayers har aldrig varit en större användarupplevelse på  mobil enhet då det är både stort och tungkört för en segare enhet. Samt att de aldrig var tänkte från början att fungera för  touchbaserade enheter, utan de är stöd som  senare har lagts på.

    Därför har jag hittat ett annat fullgott  alternativ till OpenLayers som heter Leaflet, som är anpassat att ha alla funktioner som  man kan kräva av en webbaserad karta och samtidigt fungera i mobila touch enheteter. Leaflet använder alla nya webbtekniker som HTML5 och CSS3 i största möjliga mån för att få sådan bra upplevelse som möjligt.

    Jag gjorde om hela klientdelen av en realtidskarta för blixtar i Leaflet istället, så att den skulle fungera bättre på en mobil enhet än vad den tidigare gjorde. Med denna implementation så visade sig att Leaflet kunde nå upp till alla krav som man kan ställa på en webbaserad karta. Resultatet blev en mycket lättare och snabbare klient med samma funktionalitet som den förra hade.

  • 79.
    Berekovic, Mladen
    et al.
    Technical University of Carolo Wilhelmina Braunschweig, Germany .
    Chakraborty, Samarjit
    Technical University of Munich, Germany .
    Eles, Petru Ion
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Pimentel, Andy D
    University of Amsterdam, Netherlands .
    Editorial Material: Introduction to the Special Section on ESTIMedia082012In: ACM Transactions on Embedded Computing Systems, ISSN 1539-9087, E-ISSN 1558-3465, Vol. 11, no 1Article in journal (Other academic)
    Abstract [en]

    n/a

  • 80.
    Berg, Emil
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Ad-hoc Routing in Low Bandwidth Environments2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    AODV (Ad hoc On-demand Distance Vector routing), DSDV (Destination-Sequenced Distance-Vector routing), DSR (Dynamic Source Routing), and OLSR (Optimized Link State Routing protocol) are protocols used for routing management in ad-hoc networks. In a specific sensor data network application, nodes need information about the network topology, i.e. the network nodes and the connections between them. OLSR provides nodes with this information, while the three other protocols do not. This thesis investigates how OLSR compares to AODV, DSDV,and DSR in a low bandwidth network scenario. Two cases were analyzed: One where AODV, DSDV, and DSR distribute topology information in the application layer and one where they do not.

    The sensor data application was not finished when this thesis project started. Instead, a simplified traffic model of the application was used. In addition to a protocol comparison, this thesis investigates if traffic generated from the model results in high rates of packet loss, assuming low bandwidth conditions. The ns-3 network simulator was used for these investigations.

    This thesis shows that AODV outperforms the three other protocols regardless of whether AODV, DSDV, and DSR distribute topology information in the application layer or not. Furthermore, it is shown that running the traffic model in the low bandwidth environment is not possible without high rates of packet loss.

  • 81.
    Berglund, Aseel
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Berglund, Erik
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Science & Engineering.
    Siliberto, Fabio
    University of Roma La Sapienza, Italy.
    Prytz, Erik
    Linköping University, Department of Computer and Information Science, Human-Centered systems. Linköping University, Faculty of Arts and Sciences.
    Effects of Reactive and Strategic Game Mechanics in Motion-based Games2017In: 2017 IEEE 5TH INTERNATIONAL CONFERENCE ON SERIOUS GAMES AND APPLICATIONS FOR HEALTH (SEGAH), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    Motion-based games offer positive effects on physical, social, and mental health for the players and have been common during the past decade, enabled by commercial motion tracking devices. However, little is known about the impact of game mechanics on the player experience, movement, and performance in motion-based games. In this paper we present results from a study with 35 participants comparing two different game mechanics, one reactive and one strategic, for a casual motion-based game. The assumption was that a more strategic mechanic would lead to less movement but more enjoyment. However, there was no significant difference in player experience, performance, or movement between the two game mechanics. In addition, a key aspect for the players preferred game mechanics was the perceived amount of thinking the game mechanic required.

  • 82.
    Berglund, Aseel
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Heintz, Fredrik
    Linköping University, Department of Computer and Information Science, Artificial Intelligence and Intergrated Computer systems. Linköping University, The Institute of Technology.
    Integrating Soft Skills into Engineering Education for Increased Student Throughput and more Professional Engineers2014In: Proceedings of LTHs 8:e Pedagogiska Inspirationskonferens (PIK), Lund, Sweden: Lunds university , 2014Conference paper (Other academic)
    Abstract [en]

    Soft skills are recognized as crucial for engineers as technical work is becoming more and more collaborative and interdisciplinary. Today many engineering educations fail to give appropriate training in soft skills. Linköping University has therefore developed a completely new course “Professionalism for Engineers” for two of its 5-year engineering programs in the area of computer science. The course stretches over the first 3 years with students from the three years taking it together. The purpose of the course is to give engineering students training in soft skills that are of importance during the engineering education as well as during their professional career. The examination is based on the Dialogue Seminar Method developed for learning from experience and through reflection. The organization of the course is innovative in many ways.

  • 83.
    Bergström, Gustav
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Duberg, Elsa
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Holmén, Karin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Lundell, Tobias
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Lönnberg, Robert
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Mandelius, Marcus
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Olsson, Christian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Ström, Björn
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Äng, Oscar
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    A study in web development: An onlinewatch store as a web application2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This is a report on the development and implementation of the web shop “Urballa Ur”, a web application developed by nine students at Linköping university. The report illustrates the methodology and process with intention to answer the question “How can an online watch store be implemented to increase sales?”. During the process the agile method scrum has been used as a working method. A survey and a market plan was created and the results were used as a foundation for the backlog and implementation process. Additionally, a thorough theoretical study was conducted to found the report in academic research. The results of the study is discussed and the conclusion shows that, by creating a thorough backlog and a solid theoretical background, it is possible to develop a web shop with the requirements to answer the question.

  • 84. Bernardo, V.
    et al.
    Braun, T.
    Curado, M.
    Fiedler, M.
    Hock, D.
    Hossmann, T.
    Hummel, K. A.
    Hurni, P.
    Ickin, S.
    Jamakovic-Kapic, A.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Trinh, A.
    Vergara, Ekhiotz
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Wamser, F.
    Zinner, T.
    Green Wireless-Energy Efficiency in Wireless Networks2015In: Large-Scale Distributed Systems and Energy Efficiency, John Wiley and Sons , 2015Chapter in book (Refereed)
  • 85.
    Berzinji, A.
    et al.
    University of Sulaimani, Sulaimani, Iraq.
    Kaati, L.
    FOI, Stockholm, Sweden.
    Rezine, Ahmed
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Detecting key players in terrorist networks2012In: Proceedings - 2012 European Intelligence and Security Informatics Conference, EISIC 2012, IEEE, 2012, 297-302 p.Conference paper (Refereed)
    Abstract [en]

    The interest in analyzing loosely connected and decentralized terrorist networks of global reach has grown during the past decade. Social Network Analysis (SNA) is one approach towards understanding terrorist networks since it can be used to analyze the structure of a network and to detect important persons and links. In this work we study decentralized terrorist networks with different types of nodes. The nodes can be either organizations, places or persons. We use a combination of different centrality measures to detect key players in such networks.

  • 86.
    Bhat, Anand
    et al.
    Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA.
    Samii, Soheil
    Linköping University, Department of Computer and Information Science, Software and Systems. General Motors, USA.
    Rajkumar, Ragunathan
    Electr. & Comput. Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA.
    Practical Task Allocation for Software Fault-Tolerance and Its Implementation in Embedded Automotive Systems2017Conference paper (Refereed)
    Abstract [en]

    Due to the advent of active safety features and automated driving capabilities, the complexity of embedded computing systems within automobiles continues to increase. Such advanced driver assistance systems (ADAS) are inherently safety-critical and must tolerate failures in any subsystem. However, fault-tolerance in safety-critical systems has been traditionally supported by hardware replication, which is prohibitively expensive in terms of cost, weight, and size for the automotive market. Recent work has studied the use of software-based fault-tolerance techniques that utilize task-level hot and cold standbys to tolerate fail-stop processor and task failures. The benefit of using standbys is maximal when a task and any of its standbys obey the placement constraint of not being co-located on the same processor. We propose a new heuristic based on a "tiered" placement constraint, and show that our heuristic produces a better task assignment that saves at least one processor up to 40% of the time relative to the best known heuristic to date. We then introduce a task allocation algorithm that, for the first time to our knowledge, leverages the run-time attributes of cold standbys. Our empirical study finds that our heuristic uses no more than one additional processor in most cases relative to an optimal allocation that we construct for evaluation purposes using a creative technique. We have designed and implemented our software fault-tolerance framework in AUTOSAR, an automotive industry standard. We use this implementation to provide an experimental evaluation of our task-level fault-tolerance features. Finally, we present an analysis of the worst-case behavior of our task recovery features.

  • 87.
    Bianzino, Aruna Prem
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Asplund, Mikael
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Vergara Alonso, Ekhiotz Jon
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Nadjm-Tehrani, Simin
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Cooperative proxies: Optimally trading energy and quality of service in mobile devices2014In: Computer Networks, ISSN 1389-1286, E-ISSN 1872-7069, Vol. 75, no Part A, 297-312 p.Article in journal (Refereed)
    Abstract [en]

    This work studies the energy and quality of service (QoS) trade-off in the context of mobile devices with two communication interfaces (a high energy and a low energy interface). We propose an optimisation scheme during underload scenarios where proxy groups are dynamically formed exploiting both interfaces. The scheme integrates a reward mechanism that compensates a proxy while carrying other group members’ traffic, and deals with churn (joining and leaving of nodes) in a cell area. For traffic flows that approximate knowledge about current services we show that the scheme can achieve energy savings of 60% for all mobile nodes as whole. We also demonstrate the impact on disruption-sensitive flows as a function of the traffic mix, and that the use of rewards for selection of proxies is a fair mechanism in the long term.

  • 88.
    Bianzino, Aruna Prem
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Rougier, Jean-Louis
    Telecom ParisTech.
    Chaudet, Claude
    Telecom ParisTech.
    Rossi, Dario
    Telecom ParisTech.
    The Green-Game: Accounting for Device Criticality in Resource Consolidation for Backbone IP Networks2014In: Strategic Behavior and the Environment, ISSN 1944-012X, E-ISSN 1944-0138, Vol. 4, no 2, 131-153 p.Article in journal (Refereed)
    Abstract [en]

    The reduction of the energy expenditure of communication networks rep- resents a key issue for the research community. A promising technique acting in this direction is known as “resource consolidation”. It consists in concen- trating the workload of an infrastructure on a reduced set of devices, while switching off the others. Deciding on the set of devices that can be safely switched off requires an accurate evaluation of their criticality in the net- work. We define here a measure of criticality that takes into account the network topology, but also the traffic, and different possible network config- urations. We model the scenario as a coalitional game. Shapley value ranking is efficiently used to drive the resource consolidation procedure. Numerical results, on real network scenarios, confirm the robustness and relevance of the proposed index in measuring criticality, yielding a good tradeoff between energy efficiency and network robustness, and outperforming other classical indexes. 

  • 89.
    Biciusca, Tonino
    et al.
    Academic Romana, Romania; West University of Timisoara, Romania.
    Horga, Adrian
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering. Academic Romana, Romania.
    Sofonea, Victor
    Academic Romana, Romania.
    Simulation of liquid-vapour phase separation on GPUs using Lattice Boltzmann models with off-lattice velocity sets2015In: Comptes rendus. Mecanique, ISSN 1631-0721, E-ISSN 1873-7234, Vol. 343, no 10-11, 580-588 p.Article in journal (Refereed)
    Abstract [en]

    We use a two-dimensional Lattice Boltzmann model to investigate the liquid-vapour phase separation in an isothermal van der Waals fluid. The model is based on the expansion of the distribution function up to the third order in terms of Hermite polynomials. In two dimensions, this model is an off-lattice one and has 16 velocities. The Corner Transport Upwind Scheme is used to evolve the corresponding distribution functions on a square lattice. The resulting code allows one to follow the liquid-vapour phase separation on lattices up to 4096 x 4096 nodes using a Tesla M2090 Graphics Processing Unit. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

  • 90.
    Billman, Johan
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Hellström, Victor
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Abusing Keep-Alive Forwarding to flood a VANET: When safety messages become a safety risk2016Independent thesis Basic level (university diploma), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Cooperative Intelligent Transport Systems (C-ITS) enable vehicles to cooperate with each other and can be used to increase traffic safety and traffic flow. There are several standard initiatives for C-ITS, such as WAVE in the US, ARIB in Japan and ETSI ITS G5 in Europe.

    Decentralized Environment Notification Message (DENM) is a kind of message within ETSI TC ITS. DENMs are event-triggered, multi-hop notification messages that can be for- warded using Keep-Alive Forwarding (KAF).

    In this thesis, KAF is used to flood the network with DENMs sent from a single attack- ing vehicle. Using the simulation tools SUMO, OmNet++ and Veins, a highway scenario is studied. In the scenario, a vehicle sends out a DENM into a network that is being attacked by one other vehicle. Due to how KAF allows messages to be forwarded the other vehicles help flood the network. The results clearly indicate that KAF can be abused to create a Denial of Service (DoS) attack. After just a few seconds, the attack has introduced large de- lays and very high packet loss. The delay to receive a DENM is increased by several orders of magnitude and the packet loss reach unacceptable levels. By getting DENMs several seconds after they are needed, or by not getting them at all, could lead to traffic hazards. 

  • 91.
    Birksjö, Marcus
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Event-based diagnostics in heavy-duty vehicles2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The integration of small computer units in vehicles has made new and more complex functionalitypossible within the vehicle industry. To verify that the functionality is working and to troubleshoot it when a fault is detected requires a set of diagnostic services. Due to the increasing complexity of the functionality the diagnostic services need to extract more data to be able to diagnose the functionality. This causes an increased network load which soon threatens to become too high for some of the current networks. New ways to diagnose functionality in vehicles are therefore needed.

    The aim of this thesis was to investigate the need for an event-based service within the domain of vehicle diagnostics as well as presenting a recommendation of how sucha service should be designed. The thesis also aimed at eliciting obstacles and pitfalls connected with the implementation of the service in the current software architecture in heavy duty vehicles.

    An industrial case study was performed at the Swedish company Scania to elicit the potential need, problems and limitations with an event-based service for vehicle diagnostics. First a set of experts representing different domains within vehicle diagnostics were interviewed to investigate the need and potential of the service for different use cases. Requirements were elicited and compared with the service ResponseOnEvent defined inthe ISO standard 14229-1:2013. A decision was then made to diverge from the standard inorder to increase the number of fulfilled requirements and flexibility of the service. A new proprietary service was therefore created and evaluated through a proof of concept wherea prototype of the service was implemented in one client and one server control unit. A final recommendation was then given suggesting how to implement an event-based service and how to solve the found problems.

    The elicitation of the need for an event-based service resulted a confirmed need in three different domains and 23 different requirements which the service ResponseOnEvent was compared against. The service failed to meet all the requirements and therefore a proprietary service was designed. The prototype implementation of the proprietary service showed on multiple difficulties connected to the realization of an event-based service in the current architecture. One of the biggest was the fact that diagnostic services was assumed to always have a one-to-one relation between request and response, which an event-based service would not have. Different workarounds were discovered and assessed. Another problem was the linking between an event triggered response message and the triggercondition. It was concluded that some restrictions would have to be made to facilitatethe process of linking a response to its trigger condition. Non-determinism was another problem, since there were no guarantees that an event would not trigger too often causinga bus overload. In the final recommendation there are suggestions of how to solve these problems and some suggested areas for further research.

    The thesis confirms the need for a new way to diagnose vehicle functionality due to their increased complexity and the limited bandwidth of some of today’s in-vehicle networks. The event-based service ResponseOnEvent offers a good alternative but might lacksome key functionality. Therefore it might be valuable to consider a proprietary service instead. Due to its nature, an event-based service might require a restructuring of thesystem architecture and limitations in the hardware might limit the usability and flexibilityof the service.

    Keywords: event-based service, Response on Event, ECU, Vehicle Diagnostics, UDS,KWP.

  • 92.
    Bjelkenstedt, Alf
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Web-Based Drawing Tool in GWT with Usability Testing and Usability Evaluation2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    On behalf of Inspectera HK AB in Norrköping a web-based drawing tool has been developed in Java, mainlywith the library Google Web Toolkit (GWT). The purpose of this tool is to facilitate both the staff's at Inspecteraand their client's work with different types of drawings such as blueprints for pest control, fire protection andespecially drawings of the company's e-service of self-checks. Besides developing the drawing tool usabilitytesting and a usability evaluation has been performed.

  • 93.
    Blomquist, Linus
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Engström, Hampus
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    GPU based IP forwarding2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis was about investigating if it is feasible to implement an IP-forwarding data plane on a GPU. A GPU is energy efficient compared to other more powerful processors on the market today and should in theory be efficient to use for routing purposes. An IP-forwarding data plane consist of several things where we focused on some of the concepts. We have implemented IP-forwarding lookup operations, packet header changes, prioritization between different packets and a traffic shaper to restrict the packet throughput. To test these concepts we implemented a prototype, on a Tegra platform, in CUDA and evaluated its performance. We are able to forward 28 Mpackets/second with a best case latency of 27 µS given local simulated packets. The conclusions we can draw of this thesis work is that using a GPU for IP-forwarding purposes seems like an energy efficient solution compared to other routers on the market today. In the thesis we also tried the concept of only launching the GPU kernel once and let it be infinite which shows promising results for future work.

  • 94.
    Boberg, Hannes
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Designing and comparing access control systems2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Access control systems are an important concept in the area of computer security. In this master thesis different solutions are analyzed. The focus is on a tool called DW Access. DW Access is developed by Pdb Datasystem AB. A comparison was done that showed that DW Access is lacking some important functionality. After the comparison a base model for an access control system was designed. The new design includes concepts like relation- ships, replacements and time limited access. It also works for generic subjects and objects in the system. This design was later partly implemented in DW Access.

    The conclusions from this thesis work is that DW Access is a unique tool and there is a market for the application or similar applications. The new functionality was one step forward and the evaluation showed that the potential users liked the new concepts. But it is a very open area because of very unique requirements on the market.

  • 95.
    Bodirsky, Manuel
    et al.
    Technical University of Dresden, Germany.
    Chen, Hubie
    University of Basque Country, Spain; Basque Fdn Science, Spain.
    Wrona, Michal
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Tractability of quantified temporal constraints to the max2014In: International journal of algebra and computation, ISSN 0218-1967, Vol. 24, no 8, 1141-1156 p.Article in journal (Refereed)
    Abstract [en]

    A temporal constraint language is a set of relations that are first-order definable over (Q; less than). We show that several temporal constraint languages whose constraint satisfaction problem is maximally tractable are also maximally tractable for the more expressive quantified constraint satisfaction problem. These constraint languages are defined in terms of preservation under certain binary polymorphisms. We also present syntactic characterizations of the relations in these languages.

  • 96.
    Bodirsky, Manuel
    et al.
    Technical University of Dresden, Germany.
    Jonsson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    A Model-Theoretic View on Qualitative Constraint Reasoning2017In: The journal of artificial intelligence research, ISSN 1076-9757, E-ISSN 1943-5037, Vol. 58, 339-385 p.Article in journal (Refereed)
    Abstract [en]

    Qualitative reasoning formalisms are an active research topic in artificial intelligence. In this survey we present a model-theoretic perspective on qualitative constraint reasoning and explain some of the basic concepts and results in an accessible way. In particular, we discuss the significance of omega-categoricity for qualitative reasoning, of primitive positive interpretations for complexity analysis, and of Datalog as a unifying language for describing local consistency algorithms.

  • 97.
    Bodirsky, Manuel
    et al.
    Technical University of Dresden, Germany.
    Jonsson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Pham Trung, Van
    Vienna University of Technology, Austria.
    THE REDUCTS OF THE HOMOGENEOUS BINARY BRANCHING C-RELATION2016In: Journal of Symbolic Logic (JSL), ISSN 0022-4812, E-ISSN 1943-5886, Vol. 81, no 4, 1255-1297 p.Article in journal (Refereed)
    Abstract [en]

    Let (L; C) be the (up to isomorphism unique) countable homogeneous structure carrying a binary branching C-relation. We study the reducts of (L; C), i.e., the structures with domain L that are first-order definable in (L; C). We show that up to existential interdefinability, there are finitely many such reducts. This implies that there are finitely many reducts up to first-order interdefinability, thus confirming a conjecture of Simon Thomas for the special case of (L; C). We also study the endomorphism monoids of such reducts and show that they fall into four categories.

  • 98. Bodirsky, Manuel
    et al.
    Jonsson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems.
    Van Pham, Trung
    The Complexity of Phylogeny Constraint Satisfaction2016Conference paper (Refereed)
  • 99.
    Bodirsky, Manuel
    et al.
    Technical University of Dresden, Germany.
    Jonsson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Van Pham, Trung
    Vietnam Academy of Science and Technology, Hanoi, Vietnam.
    The Complexity of Phylogeny Constraint Satisfaction Problems2017In: ACM Transactions on Computational Logic, ISSN 1529-3785, E-ISSN 1557-945X, Vol. 18, no 3, 23Article in journal (Refereed)
    Abstract [en]

    We systematically study the computational complexity of a broad class of computational problems in phylogenetic reconstruction. The class contains, for example, the rooted triple consistency problem, forbidden subtree problems, the quartet consistency problem, and many other problems studied in the bioinformatics literature. The studied problems can be described as constraint satisfaction problems, where the constraints have a first-order definition over the rooted triple relation. We show that every such phylogeny problem can be solved in polynomial time or is NP-complete. On the algorithmic side, we generalize a well-known polynomial-time algorithm of Aho, Sagiv, Szymanski, and Ullman for the rooted triple consistency problem. Our algorithm repeatedly solves linear equation systems to construct a solution in polynomial time. We then show that every phylogeny problem that cannot be solved by our algorithm is NP-complete. Our classification establishes a dichotomy for a large class of infinite structures that we believe is of independent interest in universal algebra, model theory, and topology. The proof of our main result combines results and techniques from various research areas: a recent classification of the model-complete cores of the reducts of the homogeneous binary branching C-relation, Leebs Ramsey theorem for rooted trees, and universal algebra.

  • 100.
    Bodirsky, Manuel
    et al.
    Ecole Polytechnique, Palaiseau, France.
    Jonsson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    von Oertzen, Timo
    Max-Planck-Institute for Human Development, Berlin, Germany and University of Virginia, Charlottesville, USA..
    Essential Convexity and Complexity of Semi-algebraic Constraints2012In: Logical Methods in Computer Science, ISSN 1860-5974, Vol. 8, no 4Article in journal (Refereed)
    Abstract [en]

    Let \Gamma be a structure with a finite relational signature and a first-order definition in (R;*,+) with parameters from R, that is, a relational structure over the real numbers where all relations are semi-algebraic sets. In this article, we study the computational complexity of constraint satisfaction problem (CSP) for \Gamma: the problem to decide whether a given primitive positive sentence is true in \Gamma. We focus on those structures \Gamma that contain the relations \leq, {(x,y,z) | x+y=z} and {1}. Hence, all CSPs studied in this article are at least as expressive as the feasibility problem for linear programs. The central concept in our investigation is essential convexity: a relation S is essentially convex if for all a,b\inS, there are only finitely many points on the line segment between a and b that are not in S. If \Gamma contains a relation S that is not essentially convex and this is witnessed by rational points a,b, then we show that the CSP for \Gamma is NP-hard. Furthermore, we characterize essentially convex relations in logical terms. This different view may open up new ways for identifying tractable classes of semi-algebraic CSPs. For instance, we show that if \Gamma is a first-order expansion of (R;*,+), then the CSP for \Gamma can be solved in polynomial time if and only if all relations in \Gamma are essentially convex (unless P=NP).

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