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  • 1.
    Abbas, Syed Muhammad
    et al.
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Data- och elektroteknik. Högskolan i Jönköping, Tekniska Högskolan. Högskolan i Jönköping.
    Henricsson, Christopher
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Data- och elektroteknik. Högskolan i Jönköping, Tekniska Högskolan. Högskolan i Jönköping.
    A Simulation Framework for Efficient Search in P2P Networks with 8-Point HyperCircles2008Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report concerns the implementation of a simulation framework to evaluate an emerging peer-to-peer network topology scheme using 8-point hypercircles, entitled HyperCircle. This topology was proposed in order to alleviate some of the drawbacks of current P2P systems evolving in an uncontrolled manner, such as scalability issues, network overload and long search times. The framework is supposed to be used to evaluate the advantages of this new topology. The framework has been built on top of an existing simulator software solution, the selection of which was an important part of the development. Weighing different variables such as scalability and API usability, the selection fell on OverSim, an open-source discreet-event simulator based on OMNET++.

    After formalizing the protocol for easier implementation, as well as extending it for better performance, implementation followed using C++ with OverSim’s API and simulation library. Implemented as a module (alongside other stock modules providing their own protocols such as Chord and Kademlia), it can be used in OverSim to simulate a user-defined network using one of the simulation routine applications provided (or using a custom application written by the user). For the purposes of this thesis, the standard application KBRTestApp was used; an application sending test messages between randomly selected nodes, while adding and removing nodes at specific time intervals. The adding and removing of nodes can be configured with probability parameters.

    Tentative testing shows that this implementation of the HyperCircle protocol has a certain performance gain over the OverSim implementations of the Chord and Kademlia protocols, measurable in the time it takes a message to get from sender to recipient. Further testing is outside the scope of this thesis.

  • 2.
    Abdulla, PA
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. DEPARTMENT OF COMPUTER SYSTEMS.
    Boasson, L
    Bouajjani, A
    Effective Lossy Queue Languages.2001Inngår i: ICALP'2001, 28th Int. Colloquium on Automata, Languages and Programmming., 2001Konferansepaper (Fagfellevurdert)
  • 3.
    Abdulla, PA
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. DEPARTMENT OF COMPUTER SYSTEMS.
    Jonsson, B
    Channel Abstractions in Protocol Verification2001Inngår i: CONCUR'2001, 12th Int. Conf. on Concurrency Theory, 2001Konferansepaper (Fagfellevurdert)
  • 4.
    Abdulla, Parosh A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Delzanno, Giorgio
    Univ Genoa, DIBRIS, Genoa, Italy..
    Parameterized verification2016Inngår i: International Journal on Software Tools for Technology Transfer (STTT), ISSN 1433-2779, E-ISSN 1433-2787, Vol. 18, nr 5, 469-473 s.Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    The goal of parameterized verification is to prove the correctness of a system specification regardless of the number of its components. The problem is of interest in several different areas: verification of hardware design, multithreaded programs, distributed systems, and communication protocols. The problem is undecidable in general. Solutions for restricted classes of systems and properties have been studied in areas like theorem proving, model checking, automata and logic, process algebra, and constraint solving. In this introduction to the special issue, dedicated to a selection of works from the Parameterized Verification workshop PV '14 and PV '15, we survey some of the works developed in this research area.

  • 5.
    Abdulla, Parosh A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Delzanno, Giorgio
    Univ Genoa, Genoa, Italy..
    Montali, Marco
    Free Univ Bolzano, Bolzano, Italy..
    Well Structured Transition Systems with History2015Inngår i: Electronic Proceedings in Theoretical Computer Science, ISSN 2075-2180, E-ISSN 2075-2180, nr 193, 115-128 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose a formal model of concurrent systems in which the history of a computation is explicitly represented as a collection of events that provide a view of a sequence of configurations. In our model events generated by transitions become part of the system configurations leading to operational semantics with historical data. This model allows us to formalize what is usually done in symbolic verification algorithms. Indeed, search algorithms often use meta-information, e.g., names of fired transitions, selected processes, etc., to reconstruct (error) traces from symbolic state exploration. The other interesting point of the proposed model is related to a possible new application of the theory of well-structured transition systems (wsts). In our setting wsts theory can be applied to formally extend the class of properties that can be verified using coverability to take into consideration (ordered and unordered) historical data. This can be done by using different types of representation of collections of events and by combining them with wsts by using closure properties of well-quasi orderings.

  • 6. Abdulla, Parosh Aziz
    Carrying Probabilities to the Infinite World2011Inngår i: CONCUR'2011, 22nd International Conference on Concurrency Theory., 2011Konferansepaper (Fagfellevurdert)
  • 7.
    Abdulla, Parosh Aziz
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. DEPARTMENT OF COMPUTER SYSTEMS.
    Using (Timed) Petri Nets for Verification of Parametrized (Timed) Systems2001Inngår i: VEPAS'2001, Verification of Parameterized Systems, 2001Konferansepaper (Fagfellevurdert)
  • 8.
    Abdulla, Parosh Aziz
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Atig, Mohamed Faouzi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Kaxiras, Stefanos
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorarkitektur och datorkommunikation.
    Leonardsson, Carl
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Ros, Alberto
    Zhu, Yunyun
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Fencing programs with self-invalidation and self-downgrade2016Inngår i: Formal Techniques for Distributed Objects, Components, and Systems, Springer, 2016, 19-35 s.Konferansepaper (Fagfellevurdert)
  • 9.
    Abdulla, Parosh Aziz
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Chen, Yu-Fang
    Clemente, Lorenzo
    Holík, Lukás
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Hong, Chih-Duo
    Mayr, Richard
    Vojnar, Tomás
    Advanced Ramsey-based Büchi automata inclusion testing2011Inngår i: CONCUR 2011 — Concurrency Theory, Springer Berlin/Heidelberg, 2011, 187-202 s.Konferansepaper (Fagfellevurdert)
  • 10.
    Abdulla, Parosh Aziz
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Delzanno, Giorgio
    Univ Genoa, I-16126 Genoa, Italy..
    Rezine, Othmane
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Uppsala Univ, Uppsala, Sweden..
    Sangnier, Arnaud
    Univ Paris Diderot, CNRS, LIAFA, Paris, France..
    Traverso, Riccardo
    FBK, Trento, Italy..
    Parameterized verification of time-sensitive models of ad hoc network protocols2016Inngår i: Theoretical Computer Science, ISSN 0304-3975, E-ISSN 1879-2294, Vol. 612, 1-22 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We study decidability and undecidability results for parameterized verification of a formal model of timed Ad Hoc network protocols. The communication topology is defined by an undirected graph and the behaviour of each node is defined by a timed automaton communicating with its neighbours via broadcast messages. We consider parameterized verification problems formulated in terms of reachability. In particular we are interested in searching for an initial configuration from which an individual node can reach an error state. We study the problem for dense and discrete time and compare the results with those obtained for (fully connected) networks of timed automata.

  • 11.
    Abdulla, Parosh Aziz
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi.
    Delzanno, Giorgio
    Van Begin, Laurent
    A classification of the expressive power of well-structured transition systems2011Inngår i: Information and Computation, ISSN 0890-5401, E-ISSN 1090-2651, Vol. 209, nr 3, 248-279 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We compare the expressive power of a class of well-structured transition systems that includes relational automata (extensions of), Petri nets, lossy channel systems, constrained multiset rewriting systems, and data nets. For each one of these models we study the class of languages generated by labeled transition systems describing their semantics. We consider here two types of accepting conditions: coverability and reachability of a fixed a priori configuration. In both cases we obtain a strict hierarchy in which constrained multiset rewriting systems is the most expressive model.

  • 12.
    Abdulla, Parosh Aziz
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Datorteknik.
    Jonsson, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Datorteknik.
    Model checking of systems with many identical timed processes2003Inngår i: Theoretical Computer Science, ISSN 0304-3975, Vol. 290, nr 1, 241-264 s.Artikkel i tidsskrift (Fagfellevurdert)
  • 13. Abdulla, Parosh Aziz
    et al.
    Leino, Rustan
    TACAS'2011, 17th International ConferenceTools and Algorithms for the Construction and Analysis of Systems.2011Konferanseproceedings (Fagfellevurdert)
  • 14.
    Abdulla, Parosh Aziz
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik.
    Richard, Mayr
    Computing Optimal Coverability Costs in Priced Timed Petri Nets2011Inngår i: LICS'2011, Proceedings of the 26th Annual IEEE Symposium on Logic in Computer Science, 2011, 399-408 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We consider timed Petri nets, i.e., unbounded Petri nets where each token carries a real-valued clock. Transition arcs are labeled with time intervals, which specify constraints on the ages of tokens. Our cost model assigns token storage costs per time unit to places, and firing costs to transitions. We study the cost to reach a given control-state. In general, a cost-optimal run may not exist. However, we show that the infimum of the costs is computable.

  • 15.
    Abdulla, Parosh
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. DoCS.
    Ben Henda, Noomene
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. DoCS.
    Mayr, Richard
    Sandberg, Sven
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Datalogi.
    Limiting Behavior of Markov Chains with Eager Attractors2006Inngår i: Third International Conference on the Quantitative Evaluation of Systems (QEST), 2006, 253-262 s.Konferansepaper (Fagfellevurdert)
  • 16.
    Abrahamsson, Björn
    Linköpings universitet, Institutionen för systemteknik.
    Architectures for Multiplication in Galois Rings2004Independent thesis Basic level (professional degree)Oppgave
    Abstract [en]

    This thesis investigates architectures for multiplying elements in Galois rings of the size 4^m, where m is an integer.

    The main question is whether known architectures for multiplying in Galois fields can be used for Galois rings also, with small modifications, and the answer to that question is that they can.

    Different representations for elements in Galois rings are also explored, and the performance of multipliers for the different representations is investigated.

  • 17.
    Abrahamsson, Henrik
    Mälardalens högskola, Akademin för innovation, design och teknik.
    Internet Traffic Management2008Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 18.
    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.

  • 19.
    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, 916-921 s.Konferansepaper (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

  • 20.
    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, 187-193 s.Konferansepaper (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.

  • 21.
    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, 199-210 s.Konferansepaper (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.

  • 22.
    Abrahamsson, Lars
    Linköpings universitet, Institutionen för systemteknik.
    A portal based system for indoor environs2006Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this thesis is to document the development of the graphics part of an extremely pluggable game engine/lab environment for a course in advanced game programming. This thesis is one out of five, and concerns indoor, realtime computer 3D graphics. It covers state-of-the-art techniques such as GLSL - the OpenGL Shading Language - and more well known techniques such as portal based rendering.

  • 23.
    Abrahamsson, Marcus
    Linköpings universitet, Institutionen för datavetenskap, Databas och informationsteknik. Linköpings universitet, Tekniska högskolan.
    A platform for third-party applications on the web2013Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    A trend seen on the web today is to create a platform where externally developed applications can run inside some kind of main application. This is often done by providing an API to access data and business logic of your service and a sandbox environment in which third-party applications can run. By providing this, it is made possible for external developers to come up with new ideas based on your service. Some good examples on this are Spotify Apps, Apps on Facebook and SalesForce.com.

    Ipendo Systems AB is a company that develops a web platform for intellectual properties. Currently most things on this platform are developed by developers at Ipendo Systems AB. Some interest has though risen to enable external developers to create applications that will in some way run inside the main platform.

    In this thesis an analysis of already existing solutions has been done. These solutions were Spotify Apps and Apps on Facebook. The two have different approaches on how to enable third-party applications to run inside their own service. Facebook’s solution builds mainly on iframe embedded web pages where data access is provided through a web API. Spotify on the other hand hosts the third-party applications themselves but the applications may only consist of HTML5, CSS3 and JavaScript.

    In addition to the analysis a prototype was developed. The purpose of the prototype was to show possible ways to enable third-party applications to run inside your own service. Two solutions showing this were developed. The first one was based on Facebook’s approach with iframing of external web pages. The second was a slightly modified version of Spotify’s solution with only client-side code hosted by the main application. To safely embed the client side code in the main application a sandboxing tool for JavaScript called Caja was used.

    Of the two versions implemented in the prototype was the Iframe solution considered more ready to be utilized in a production environment than Caja. Caja could be seen as an interesting technique for the future but might not be ready to use today. The reason behind this conclusion was that Caja decreased the performance of the written JavaScript as well as adding complexity while developing the third-party applications.

  • 24.
    Abrahamsson, Robin
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
    Berntsen, David
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system.
    Comparing modifiability of React Native and two native codebases2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Creating native mobile application on multiple platforms generate a lot of duplicate code. This thesis has evaluated if the code quality attribute modifiability improves when migrating to React Native. One Android and one iOS codebase existed for an application and a third codebase was developed with React Native. The measurements of the codebases were based on the SQMMA-model. The metrics for the model were collected with static analyzers created specifically for this project. The results created consists of graphs that show the modifiability for some specific components over time and graphs that show the stability of the platforms. These graphs show that when measuring code metrics on applications over time it is better to do this on a large codebase that has been developed for some time. When calculating a modifiability value the sum of the metrics and the average value of the metrics between files should be used and it is shown that the React Native platform seems to be more stable than native.

  • 25.
    Adolfsson, Klas
    Linköpings universitet, Institutionen för systemteknik.
    TCP performance in an EGPRS system2003Independent thesis Advanced level (degree of Magister), 20 poäng / 30 hpOppgave
    Abstract [en]

    The most widely used protocol for providing reliable service and congestion control in the Internet is the Transmission Control Protocol (TCP). When the Internet is moving towards more use in mobile applications it is getting more important to know how TCP works for this purpose.

    One of the technologies used for mobile Internet is the Enhanced General Packet Radio Service (EGPRS) extension to the popular GSM system. This thesis presents a low-level analysis of TCP performance in an EGPRS system and an overview of existing TCP, GSM and EGPRS technologies.

    The bottleneck in an EGPRS system is the wireless link – the connection between the mobile phone and the GSM base station. The data transfer over the wireless link is mainly managed by the complex RLC/MAC protocol.

    In this thesis, simulations were made to identify some problems with running TCP and RLC/MAC together. The simulations were made using existing EGPRS testing software together with a new TCP module. The simulation software is also briefly described in the thesis.

    Additionaly, some suggestions are given in order to enhance performance, both by changing the EGPRS system and by modifying the TCP algorithms and parameters.

  • 26.
    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, 195-206 s.Konferansepaper (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.

  • 27.
    Agelis, Sacki
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jacobsson, Sofia
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Alping, Arne
    Ericsson Microwave Systems, Mölndal, Sweden.
    Ligander, Per
    Ericsson Microwave Systems, Mölndal, Sweden.
    Modular interconnection system for optical PCB and backplane communication2002Inngår i: Parallel and Distributed Processing Symposium., Proceedings International, IPDPS 2002, Abstracts and CD-ROM, Los Alamitos, Calif.: IEEE Press, 2002, 245-250 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a way of building modular systems with a powerful optical interconnection network. Each module, placed on a Printed Circuit Board (PCB), has a generic optical communication interface with a simple electronic router. Together with optical switching using micro-electromechanical system (MEMS) technology, packet switching over reconfigurable topologies is possible. The interconnection system gives the possibility to integrate electronics with optics without changing existing PCB technology. Great interest from industry is therefore expected and the cost advantages are several: reuse of module designs, module upgrades without changing the PCB, low-cost conventional PCB technology, etc. In the version described in this paper, the interconnection system has 48 bidirectional optical channels for intra-PCB communication on each board. For inter-PCB communication, a backplane with 192 bidirectional optical channels supports communication between twelve PCBs. With 2.5 Gbit/s per optical channel in each direction, the aggregated intra-PCB bit rate is 120 Gbit/s full duplex (on each PCB) while the aggregated inter-PCB bit rate is 480 Gbit/s full duplex. A case study shows the feasibility of the interconnection system in a parallel processing system for radar signal processing.

  • 28.
    Agelis, Sacki
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Optoelectronic router with MOEMS–based reconfigurable shuffle network2004Konferansepaper (Fagfellevurdert)
  • 29.
    Agrawal, P.
    et al.
    Uppsala Universitet.
    Ahlén, Anders
    Uppsala Universitet.
    Olofsson, Tomas
    Uppsala Universitet.
    Gidlund, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för informations- och kommunikationssystem.
    Long Term Channel Characterization for Energy Efficient Transmission in Industrial Environments2014Inngår i: IEEE Transactions on Communications, ISSN 0090-6778, E-ISSN 1558-0857, Vol. 62, nr 8, 3004-3014 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the challenges for a successful use of wireless sensor networks in process industries is to design networks with energy efficient transmission, to increase the lifetime of the deployed network while maintaining the required latency and bit-error rate. The design of such transmission schemes depend on the radio channel characteristics of the region. This paper presents an investigation of the statistical properties of the radio channel in a typical process industry, particularly when the network is meant to be deployed for a long time duration, e.g., days, weeks, and even months. Using 17–20-h-long extensive measurement campaigns in a rolling mill and a paper mill, we highlight the non-stationarity in the environment and quantify the ability of various distributions, given in the literature, to describe the variations on the links. Finally, we analyze the design of an optimal received signal-to-noise ratio (SNR) for the deployed nodes and show that improper selection of the distribution for modeling of the variations in the channel can lead to an overuse of energy by a factor of four or even higher.

  • 30.
    Agrawal, Piyush
    et al.
    Uppsala University.
    Ahlén, Anders
    Uppsala University.
    Olofsson, Tomas
    Uppsala University.
    Gidlund, Mikael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för informations- och kommunikationssystem.
    Characterization of Long Term Channel Variations in Industrial Wireless Sensor Networks2014Inngår i: IEEE International Conference on Communications (ICC'14), IEEE conference proceedings, 2014Konferansepaper (Fagfellevurdert)
  • 31.
    Ahlberg, Tobias
    et al.
    Högskolan i Kalmar, Institutionen för kommunikation och design.
    Södergren, Marcus
    Högskolan i Kalmar, Institutionen för kommunikation och design.
    Voss, Martin
    Högskolan i Kalmar, Institutionen för kommunikation och design.
    Microsoft Windows Server 2008 Terminal Services vs. Citrix XenApp2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Den här rapporten undersöker om gränsen mellan Terminal Services och Citrix XenApp har börjat suddas ut eller om man ännu kan dra en tydlig linje mellan dessa. Detta för att avgöra om organisationer som idag kör Windows Server 2003 med Citrix XenApp enbart klarar sig med de nya funktionerna i Windows Server 2008 Terminal Services och ändå uppfylla de krav och behov en organisation har. Arbetet genomfördes rent teoretiskt. För att avgöra likheter och skillnader mellan applikationerna, så användes till största delen ett ramverk. För att kunna få en bild av hur applikationerna tillämpas rent praktiskt, användes tidigare testar samt analyser. Resultatet visar att Terminal Services tagit ett större steg inom marknaden för applikationsvirtualisering. Slutsatsen antyder att Windows Server 2008 Terminal Services är lämplig för organisationer utan komplexa behov.

  • 32.
    Ahlgren, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för datorteknik. Swedish Institute of Computer Science.
    Improving Computer Communication Performance by Reducing Memory Bandwidth Consumption1997Doktoravhandling, med artikler (Annet vitenskapelig)
  • 33.
    Ahlström, Daniel
    Linköpings universitet, Institutionen för datavetenskap. Linköpings universitet, Tekniska högskolan.
    Minimizing memory requirements for deterministic test data in embedded testing2010Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [en]

    Embedded and automated tests reduce maintenance costs for embedded systems installed in remote locations. Testing multiple components of an embedded system, connected on a scan chain, using deterministic test patterns stored in a system provide high fault coverage but require large system memory. This thesis presents an approach to reduce test data memory requirements by the use of a test controller program, utilizing the observation of that there are multiple components of the same type in a system. The program use deterministic test patterns specific to every component type, which is stored in system memory, to create fully defined test patterns when needed. By storing deterministic test patterns specific to every component type, the program can use the test patterns for multiple tests and several times within the same test. The program also has the ability to test parts of a system without affecting the normal functional operation of the rest of the components in the system and without an increase of test data memory requirements. Two experiments were conducted to determine how much test data memory requirements are reduced using the approach presented in this thesis. The results for the experiments show up to 26.4% reduction of test data memory requirements for ITC´02 SOC test benchmarks and in average 60% reduction of test data memory requirements for designs generated to gain statistical data.

  • 34.
    Ahmed, Iftikhar
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Farooq, Muhammad
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Switched Multi-hop Priority Queued Networks-Influence of priority levels on Soft Real-time Performance2010Independent thesis Advanced level (degree of Master (One Year)), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    In the last few years, the number of real-time applications has increased. These applications are sensitive and require the methods to utilize existing network capacity efficiently to meet performance requirements and achieve the maximum throughput to overcome delay, jitter and packet loss. In such cases, when the network needs to support highly interactive traffic like packet-switched voice, the network congestion is an issue that can lead to various problems. If the level of congestion is high enough, the users may not be able to complete their calls and have existing calls dropped or may experience a variety of delays that make it difficult to participate smooth conversation.

    In this paper, we investigate the effect of priority levels on soft real-time performance. We use the priority queues to help us manage the congestion, handle the interactive traffic and improve the over all performance of the system. We consider switched multi-hop network with priority queues. All the switches and end-nodes control the real-time traffic with “Earlier Deadline First” scheduling. The performance of the network is characterized in terms of the average delay, the deadline missing ratio and the throughput.

    We will analyze these parameters with both the bursty traffic and evenly distributed traffic. We will analyze different priority levels and will see how the increase in priority level increases the performance of the soft real-time system.

  • 35.
    Ahmed, Olfet
    et al.
    KTH, Skolan för teknik och hälsa (STH), Data- och elektroteknik.
    Saman, Nawar
    KTH, Skolan för teknik och hälsa (STH), Data- och elektroteknik.
    Utvärdering av nätverkssäkerheten på J Bil AB2013Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete är en utvärdering av nätverkssäkerheten hos J BiL AB, både på social och teknisk nivå. Företaget är beroende av säkra Internet-anslutningar för att nå externa tjänster och interna servrar lokaliserade på olika geografiska platser. Företaget har ingen IT-ansvarig som aktivt underhåller och övervakar nätverket, utan konsulterar ett externt dataföretag. Syftet med examensarbetet är att utvärdera säkerheten, upptäcka brister, ge förbättringsförslag och till viss del implementera lösningar. För att undersöka säkerheten har observationer och intervjuer med personalen gjorts och ett flertal attacker mot nätverket har utförts. Utifrån den data som samlats in kunde slutsatsen dras att företaget har brister vad gäller IT-säkerheten. Framförallt den sociala säkerheten visade sig ha stora luckor vilket till stor del beror på att de anställda varken har blivit utbildade eller fått någon information om hur de ska hantera lösenord, datorer och IT-frågor i allmänt. Förbättringsförslag har getts och viss implementation har genomförts för att eliminera bristerna. De anställda har även med hjälp av en IT-policy och föreläsning blivit utbildade i hur de ska agera och tänka kring IT-relaterade säkerhetsfrågor.

  • 36.
    Ahmed, Tanvir
    et al.
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Tekniska fakulteten.
    Garrido, Mario
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Oscar
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Tekniska högskolan.
    A 512-point 8-parallel pipelined feedforward FFT for WPAN2011Inngår i: 2011 Conference Record of the Forty Fifth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), IEEE , 2011, 981-984 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a 512-point feedforward FFT architecture for wireless personal area network (WPAN). The architecture processes a continuous flow of 8 samples in parallel, leading to a throughput of 2.64 GSamples/s. The FFT is computed in three stages that use radix-8 butterflies. This radix reduces significantly the number of rotators with respect to previous approaches based on radix-2. Besides, the proposed architecture uses the minimum memory that is required for a 512-point 8-parallel FFT. Experimental results show that besides its high throughput, the design is efficient in area and power consumption, improving the results of previous approaches. Specifically, for a wordlength of 16 bits, the proposed design consumes 61.5 mW and its area is 1.43 mm2.

  • 37.
    Ahmed, Tanvir Saif
    et al.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Markovic, Bratislav
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Data- och elektroteknik.
    Distribuerade datalagringssystem för tjänsteleverantörer: Undersökning av olika användningsfall för distribuerade datalagringssystem2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete handlar om undersökning av tre olika användningsfall inom datalagring; Cold Storage, High Performance Storage och Virtual Machine Storage. Rapporten har som syfte att ge en översikt över kommersiella distribuerade filsystem samt en djupare undersökning av distribuerade filsystem som bygger på öppen källkod och därmed hitta en optimal lösning för dessa användnings-fall. I undersökningen ingick att analysera och jämföra tidigare arbeten där jämförelser mellan pre-standamätningar, dataskydd och kostnader utfördes samt lyfta upp diverse funktionaliteter (snapshotting, multi-tenancy, datadeduplicering, datareplikering) som moderna distribuerade filsy-stem kännetecknas av. Både kommersiella och öppna distribuerade filsystem undersöktes. Även en kostnadsuppskattning för kommersiella och öppna distribuerade filsystem gjordes för att ta reda på lönsamheten för dessa två typer av distribuerat filsystem.Efter att jämförelse och analys av olika tidigare arbeten utfördes, visade sig att det öppna distribue-rade filsystemet Ceph lämpade sig bra som en lösning utifrån kraven som sattes som mål för High Performance Storage och Virtual Machine Storage. Kostnadsuppskattningen visade att det var mer lönsamt att implementera ett öppet distribuerat filsystem. Denna undersökning kan användas som en vägledning vid val mellan olika distribuerade filsystem.

  • 38.
    Ahrengart, Hugo
    et al.
    Linköpings universitet, Institutionen för datavetenskap.
    Borg, Therese
    Linköpings universitet, Institutionen för datavetenskap.
    Magnuson, David
    Linköpings universitet, Institutionen för datavetenskap.
    Nilsson, Victor
    Linköpings universitet, Institutionen för datavetenskap.
    Partain, Beatrice
    Linköpings universitet, Institutionen för datavetenskap.
    Voss-Lagerlund, Carl
    Linköpings universitet, Institutionen för datavetenskap.
    Wagner, Mattias
    Linköpings universitet, Institutionen för datavetenskap.
    Awesome Fragrance Company: Utveckling av en e-butik för parfymprover2016Independent thesis Basic level (degree of Bachelor), 12 poäng / 18 hpOppgave
    Abstract [en]

    This bachelor's thesis accounts for the results and takeaways from the process of developing the web application for Awesome Fragrance Company. The goal of this thesis is to provide an increased understanding of how a usable web application can be designed, by studying the development of an online store with the purpose of selling fragrance samples. The agile method Scrum has been the foundation of the development, and based on this, the focus has been to develop a continuously deliverable product, where functionality is added in increments. By starting with a rough prototype and then gradually adjusting the final vision for the product based on feedback, the group has developed an online store which, according to users, is usable and intuitive. Thus, the group has created a foundation for further research on usable web applications, which was the goal of the project.

  • 39.
    Akbar, Adnan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Avdelningen för informations- och kommunikationssystem.
    Influencing Factors on Quality of Experience (QoE) in Mobile Computing2014Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Applications that can change their behaviour based on the user’s contextual appearance are called context-aware applications. Applications developed for smart phones, which carry a multitude of different sensors, and actuators have gained a huge penetration within the market. Frequent usage of mobile applications such as home automation, friend finder, car accident notification and tracking etc; have seen an increased growth from the user’s perspective. However, for such applications, it is necessary to have knowledge of the performance and cost parameters, which directly affect the QoE of the application users.  This thesis investigates possible context aware behaviours in real time situations and measures the Quality of Experience (QoE) as well as identifying the Packet Delay Variation (PDV). The background and some state-of-the-art technologies are studied, and based on these studies, three scenarios are designed and implemented and based on their QoE, results and conclusions are presented, with the  results obtained  shown by means of   graphical representations of the QoE and PDV values. 

  • 40.
    Alazawi, Salah
    et al.
    ISY, DATORSYSTEM, DI.
    Alilovic, Bojan
    ISY, DATORSSYTEM, DI.
    Konstruktion av Ethernet-baserad Qbussförlängare2008Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

     

    Syftet med var att konstruera ett bussförlängartkort till Qbussen som gör Ethernet-baserad kommunikation med I/O:t möjlig. Kortet ska kunna anslutas till standard 100 Mbits nätverksutrustning och klara autoförhandling och låsning av hastighet och duplex. Detta minskar på många ställen kabeldragningen väsentligt och det är därför önskvärt att SSAB:s egna I/O ska kunna köras så över Ethernet, antingen över vanliga nätverket eller på dedikerad kabel.

  • 41.
    Albertson, Philip
    Växjö universitet, Fakulteten för matematik/naturvetenskap/teknik, Matematiska och systemtekniska institutionen.
    WBD – Web Based Diagnostics: Identifierande av parametrar på CAN-bussen2007Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Denna rapport beskriver ett examensarbete för högskoleingenjörsexamen i datorteknik vid Växjö universitet, utfört av Philip Albertson. Vid företaget BSR i Växjö pågår utvecklingen av en ny teknik benämnd Web Based Diagnostics. Målet med projektet är att göra fordonsdiagnostik tillgängligt för bilägare till ett bra pris. Systemet består av tre delar; en modul som sätts i bilen, en server som hanterar informationen och en klient för att kunden ska kunna nå informationen. Min del i detta projekt var att identifiera hur sökta parametrar nås på CAN-bussen i bilar från VAG (Volkswagen Auto Group) och Saab. Företagets representanter var nöjda med resultatet då det utgör en bra grund för vidareutvecklingen av den prototyp för modulen som utvecklats av EDAB (Elektronik Design AB) i Sundsvall.

  • 42.
    Alekic, Anis
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Carmvall, Andreas
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för datavetenskap, fysik och matematik, DFM.
    Displayintegrering2010Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Arbetet är ett examensarbete i högskoleingenjörsutbildningen, inriktning datateknik, på Linnéuniversitet. Arcoma AB är ett företag i Växjö som utvecklar och tillverkar kompletta röntgensystem. Företaget har som mål att förbättra användarvänligheten av systemet med hjälp av en LED-display. De kan förbättra systemet genom att byta ut en enhet som styr röntgengeneratorn mot LED-displayen. Detta leder till att användaren får bättre kontroll och styrning av systemet, samtidigt som patienten behandlas.

    I rapporten beskrivs implementering av både hårdvara och mjukvara till displayen, samt den tekniska bakgrunden som till exempel HDMI och LED-tekniken. Mjukvaran har testats direkt mot displayen vilket har gjort testningen intressant. För att lösa uppgiften har vi fått använda Arcomas system och utvecklingsverktyg. Programspråket som användes var framförallt C++.

    Resultatet blev ett system som byggs upp av Arcomas hårdvaruplattform, vår kringelektronik och displayen där de sistnämnda byggdes in i en låda. Utöver displayen utvecklades en demoapplikation för generatorstyrning som styrs av en USB-mus. Arcoma är nöjda över resultatet då vi löst huvuduppgiften med displayen, men även löst de extrauppgifter som fanns. Idag försöker Arcoma skapa en efterfrågan för lösningen i deras nya produkter.

  • 43. Alesii, Roberto
    et al.
    Congiu, Roberto
    Santucci, Fortunato
    Di Marco, Piergiuseppe
    KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Fischione, Carlo
    KTH, Skolan för elektro- och systemteknik (EES), Reglerteknik. KTH, Skolan för elektro- och systemteknik (EES), Centra, ACCESS Linnaeus Centre.
    Architectures and protocols for fast identification in large-scale RFID systems2014Inngår i: ISCCSP 2014 - 2014 6th International Symposium on Communications, Control and Signal Processing, Proceedings, 2014, 243-246 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Passive tags based on backscattered signals yield low energy consumption for large-scale applications of RFIDs. In this paper, system architectures and protocol enhancements for fast identifications in ISO/IEC 18000-6C systems that integrate UWB technology are investigated. The anti-collision protocol is studied by considering various tag populations. A novel algorithm is proposed to adapt the UHF air interface parameters with the use of UWB ranging information. The results show that the proposed algorithm yields up to 25% potential performance improvement compared to the ISO/IEC 18000-6C standard.

  • 44.
    Alfredsson, Erik
    Linköpings universitet, Institutionen för systemteknik.
    Design and implementation of a hardware unit for complex division2005Independent thesis Basic level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of the thesis was to investigate and evaluate existing algorithms for division of complex numbers. The investigation should include implementation of a few suitable algorithms in VHDL. The main application for the divider is compensation for fading in a baseband processor.

    Since not much public research is done within the area of complex division in hardware, a divider based on real valued division was designed. The design only implements inversion of complex numbers instead of complete division because it is simpler and the application does not need full division, thus the required chip size is reduced.

    An examination of the different kinds of algorithms that exists for real valued division was done and two of the methods were found suitable for implementation, digit recurrence and functional iteration. From each of the two classes of algorithms one algorithm was chosen and implemented in VHDL. Two different versions of the inverter were designed for each method, one with full throughput and one with half throughput. The implementations show very similar results in terms of speed, size and performance. For most cases however, the digit recurrence implementation has a slight advantage.

  • 45.
    Alfredsson, Jonas
    Linköpings universitet, Institutionen för systemteknik.
    Portning av ett plugin till 3d-modelleringsprogram2008Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report describes the work and the results found when comparing three different 3d modeler applications. The programs are 3ds Max, Maya and Cinema 4D. The comparisons focus on the possibilities/the amount of freedom these programs interface offer to its plugins. The comparisons are made from the point of view of a tool for creating animations developed as a plugin for these modelers. This plugins demands on the system it is loaded into have been analyzed and from the results of this analysis a template have been created. This template is to be used when porting the plugin to other modeler programs in order to be able to tell at an early stage if it’s possible, or not. This template is appended as an appendix. The plugin described above is in it self a system with a plugin architecture and is described on a higher level in the report.

  • 46.
    Al-Ghareeb, Meelad
    et al.
    Högskolan i Jönköping, Tekniska Högskolan, JTH, Datateknik och informatik.
    Antranik, Sevag
    Riktlinjer för grafiska användargränssnitt för lagersystem2016Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Syftet med denna rapport är att undersöka och sammanställa riktlinjer för att utveckla ett grafiskt användargränssnitt för ett lagersystem. För att uppnå syftet med rapporten litteraturstudier, intervjuer, observationer och en prototyputveckling utfördes. Utifrån litteraturstudier visade det sig att det inte fanns specifika designriktlinjer för utveckling av lagersystem fast det fanns allmänna riktlinjer som kan användas för design av olika system. Intervjuer med utvecklare och en utvecklingschef på företaget Qsys hjälpte till att hitta befintliga riktlinjer som företaget använder. Det visade sig att de använder allmänna riktlinjer som inte är specifika för lagersystem. För att hitta mer specifika riktlinjer observerade vi några lagerarbetare för att bättre förstå hur de integrerar med det befintliga systemet som de använder. Utifrån analysen av observationerna, upptäcktes det nya riktlinjer. Med hjälp av de allmänna riktlinjer som hittades i litteraturen och riktlinjer som upptäckes efter analysen av observationer, utvecklade vi en prototyp som sedan testades. Resultatet vi fick utifrån analysen av intervjuerna med lagerarbetarna efter prototyptestning, hjälpte med att hitta ytterligare specifika riktlinjer.För att utveckla ett användarvänligt lagersystem, behöver man ett användarvänligt gränssnitt. I denna rapport presenterar vi några riktlinjer som man kan använda sig av för att utveckla ett användarvänligt gränssnitt för lagersystem.

  • 47.
    Ali Arslan, Mehmet
    et al.
    Lund University, Sweden.
    Gruian, Flavius
    Lund University, Sweden.
    Kuchcinski, Krzysztof
    Lund University, Sweden.
    Karlsson, Andreas
    Linköpings universitet, Institutionen för systemteknik. Linköpings universitet, Tekniska fakulteten.
    Code Generation for a SIMD Architecture with Custom Memory Organisation2016Inngår i: PROCEEDINGS OF THE 2016 CONFERENCE ON DESIGN AND ARCHITECTURES FOR SIGNAL and IMAGE PROCESSING, IEEE , 2016, 90-97 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Todays multimedia and DSP applications impose requirements on performance and power consumption that only custom processor architectures with SIMD capabilities can satisfy. However, the specific features of such architectures, including vector operations and high-bandwidth complex memory organization, make them notoriously complicated and time consuming to program. In this paper we present an automated code generation approach that dramatically reduces the effort of programming such architectures, by carrying out instruction scheduling and memory allocation based on a constraint programming formulation. Furthermore, the quality of the generated code is close to that of hand-written code by an experienced programmer with knowledge of the architecture. We demonstrate the viability of our approach on an existing custom heterogeneous DSP architecture, by compiling and running a number of typical DSP kernels, and comparing the results to hand-optimized code.

  • 48.
    Ali, Hayder
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Spets, Rasmus
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Virtualisering av skrivbordsmiljöer: en teknisk jämförelse2016Independent thesis Basic level (university diploma), 10 hpOppgave
    Abstract [sv]

    Detta arbete syftar till en jämförelse av olika skrivbordsvirtualiserings produkter och hur respektive miljö ser ut. I utredandeavsnittet presenteras information om skrivbordsvirtualiserings olika lösningar och hur de fungerar. Arbetet redogör för de två stora aktörerna inom detta område, Citrix och VMware. Utredandeavsnittet presenterar även lite information om Nvidias grafiklösningar i de olika miljöerna. Genomförandeavsnittet presenterar information från intervjuer med representanter från de två stora aktörerna. Arbetet presenterar även information från en representant från Nvidia, USA. Intervjuerna har skett via e-mail eftersom personligt möte varit väldigt svårt att lösa. Intervjuerna behandlar frågor om respektive lösning om hur de fungerar och även om användarvänlighet och åtkomst för användare. Fokus ligger på användarvänlighet och åtkomst för användare i respektive lösning. Efter arbetet kan det dras några slutsatser. Främst att de två miljöerna som undersökts är ganska lika när det gäller virtualisering av skrivbord. De är uppbyggda på liknande sätt och fungerar på nästan samma sätt när det gäller åtkomst för användare.

  • 49.
    Ali, Hazem
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Patoary, Mohammad Nazrul Ishlam
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Design and Implementation of an Audio Codec (AMR-WB) using Dataflow Programming Language CAL in the OpenDF Environment2010Independent thesis Advanced level (degree of Master (Two Years)), 30 poäng / 45 hpOppgave
    Abstract [en]

    Over the last three decades, computer architects have been able to achieve an increase in performance for single processors by, e.g., increasing clock speed, introducing cache memories and using instruction level parallelism. However, because of power consumption and heat dissipation constraints, this trend is going to cease. In recent times, hardware engineers have instead moved to new chip architectures with multiple processor cores on a single chip. With multi-core processors, applications can complete more total work than with one core alone. To take advantage of multi-core processors, we have to develop parallel applications that assign tasks to different cores. On each core, pipeline, data and task parallelization can be used to achieve higher performance. Dataflow programming languages are attractive for achieving parallelism because of their high-level, machine-independent, implicitly parallel notation and because of their fine-grain parallelism. These features are essential for obtaining effective, scalable utilization of multi-core processors.

    In this thesis work we have parallelized an existing audio codec - Adaptive Multi-Rate Wide Band (AMR-WB) - written in the C language for single core processor. The target platform is a multi-core AMR11 MP developer board. The final result of the efforts is a working AMR-WB encoder implemented in CAL and running in the OpenDF simulator. The C specification of the AMR-WB encoder was analysed with respect to dataflow and parallelism. The final implementation was developed in the CAL Actor Language, with the goal of exposing available parallelism - different dataflows - as well as removing unwanted data dependencies. Our thesis work discusses mapping techniques and guidelines that we followed and which can be used in any future work regarding mapping C based applications to CAL. We also propose solutions for some specific dependencies that were revealed in the AMR-WB encoder analysis and suggest further investigation of possible modifications to the encoder to enable more efficient implementation on a multi-core target system.

  • 50.
    Ali, Wajid
    et al.
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Mohammed, Shahzaan
    Linköpings universitet, Institutionen för systemteknik, Informationskodning. Linköpings universitet, Tekniska högskolan.
    Analyzing Wavelength Conversion and Traffic Grooming in Optical WDM Networks2013Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wavelength conversion and traffic grooming have been among the most researched areas and technologies of importance in optical networking. Network performance improves significantly by relaxing the wavelength continuity constraint using wavelength converters and by improving the wavelength utilization using traffic grooming. We have done a literature review that compares the performance of wavelength conversion devices with different traffic grooming devices. This thesis work analyzes the impact of increasing the number of wavelength conversion devices and grooming capable devices using different placement schemes for our proposed network model, traffic loads and link capacities. Deciding the number and location of these devices to be used in a network is equally important. This work has been done through the simulation of different device placement scenarios and the results have been analyzed using connection blocking probability as the performance metric. Our reviews and work, correctly predict the behavior of results as demonstrated by the results of other referred literatures relating to wavelength conversion and traffic grooming.

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