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  • 151. Borgh, Markus
    et al.
    Lindström, Fredric
    Waye, Kerstin Persson
    Claesson, Ingvar
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    The Effect of Own Voice on Noise Dosimeter Measurements: A Field Study in a Day-Care Environment, Including Adults and Children2008Conference paper (Refereed)
    Abstract [en]

    Noise dosimeters are valuable tools in assessing the individual noise dose in the workplace. At non-industrial work places with a high degree of communication, such measurements would include the wearer’s own voice which would be registered as noise. This may not always be desirable. The purpose of this investigation was to study the effect of the wearers own voice in noise dosimeter measurements, and especially the difference between children and adults as test subjects. The study took place at a day-care center and sixteen children and thirteen adult female preschool teachers participated. The participants wore a digital recorder during the day, which recorded the sound signal and vibrations originating from an accelerometer attached to the neck of the test subjects, for distinguishing of whether the subject was speaking or not. Thus, average A-weighted noise levels with and without the influence of the subjects own voice could be obtained. The Leq for the measurements with and without the own voice was 84.6 dBA and 72.2 dBA for the children, respectively, and 79.3 dBA and 70.0 dBA for adults. Student’s t-test showed a significant (p<0.01) difference of 12.4 dBA for children and 9.3 dBA for adults when comparing measurements including and excluding the own voice and also that the difference was significantly larger for children. Thus, the study conclude that the influence from the own voice implied an augmentation of the Leq value and that there is a significant difference between children and adults in how large this augmentation is.

  • 152. Borgh, Markus
    et al.
    Schüldt, Christian
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Claesson, Ingvar
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Efficient asynchronous re-sampling implementation on a low-power fixed-point DSP2013Conference paper (Refereed)
    Abstract [en]

    This paper presents an asynchronous resampling implementation on a low-power fixed-point DSP, which uses around 47% less computational resources compared to the solution provided by the DSP manufacturer, without compromising audio quality.

  • 153.
    Borgqvist, André
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Reliable access to synchronized world state information in peer to peer networks2005Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Virtual environments where users can interact with each other as well as with the environment are today used in many application areas ranging from military simulations to massive multiplayer online games. But no matter the application area, as soon as the number of users reaches a certain threshold, hosting a virtual environment on a single machine can become problematic. Speed and quality of the network connection will limit the number of concurrently connected users in terms of acceptable visual quality and hardware requirements of the server will be strict. With a single point of failure, system reliability could easily be compromised by means of network or host failure. Distribution of the virtual environment therefore seems a reasonable approach in order to address this problem. Hardware and network requirements would not be so critical and it would increase reliability by having no single point of failure. Unfortunately distribution introduces new problems dealing with synchronization of the world state within the distribution network. A possible solution to these problems with the focus on reliability will be presented in this thesis. The solution uses a peer to peer platform that is able to adapt to changes in the network infrastructure as a base for all communication. To improve synchronization efficiency the network will be dynamically divided into multicast groups based on synchronization needs. The solution will be tested for performance with the network fully functioning and in a number of more of less broken states to determine the reliability. The results from the tests conclude that the system is able to perform with what must be seen as acceptable performance levels even in very problematic network environments. The scalability of the system did also meet the expectations but the results would have benefited from more experimentation with larger user populations.

  • 154.
    Borkowski, Piotr
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Sending and Addressing Messages in Web Services2007Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    This thesis provides an overview of Web Services technology. The concept of Web Services and Service Oriented Architecture are explained. The thesis focuses on the mechanisms for transporting and addressing messages in web services, especially SOAP. It presents the development history of SOAP, an overview of the SOAP 1.2 specification, and the differences between SOAP in version 1.1 and 1.2. Further, the thesis presents two web servers for development and deployment of web services using Java and .NET technology, i.e. Bea Weblogic Server 9.2 and Internet Information Services 7.0. The web server implementations are evaluated both in terms of conformance to the SOAP specifications as well as their performance (response time and throughput). The results showed that the servers performed very similar both for SOAP 1.2 and SOAP 1.1 messages. The response times and throughput are similar for both servers in most cases. There are, however, situations when Weblogic perform significantly worse than IIS, and when IIS is noticeable worse than Weblogic. The thesis presents also general security aspects of sending messages.

  • 155. Bosch, Jan
    et al.
    Hedin, Görel
    Bachatene, Helene
    Koskimies, Kai
    OOSA '98: ECOOP'98 Workshop on Object-Oriented Software Architectures - Workshop summary1998Conference paper (Refereed)
    Abstract [en]

    Recently, one can recognize an increased awareness in the object-oriented research community with respect to the role of software architectures. Examples of this can, among others, be found in object-oriented frameworks and design patterns. In the call for papers for the workshop, the following topics were identified where software architecture, patterns and frameworks should be studied in more detail: – Building OO software architectures: How can design patterns, frameworks and components be included in the traditional object-oriented analysis and design? How are architecture constraints processed to build OO software architectures? Which techniques can help to build an OO architecture that supports reuse and is scalable? – Language role in architecture: What is the role of a particular object-oriented language when designing an architecture? – Architecture documentation: It has been suggested that design patterns can be used to document the design and rationale of an object-oriented architecture. How well does this work in practice? – OO architectural styles: What is the relation between the architectural styles of Garlan and Shaw and OO design? – Composition of architectures: Since object-oriented frameworks are an accepted technology within the software industry, the composition of two or more frameworks in an application occurs increasingly often. The composition may be far from trivial and the problems that may appear as well as solutions should be investigated.

  • 156. Bosch, Jan
    et al.
    Molin, Peter
    Mattsson, Michael
    Bengtsson, PerOlof
    Object-oriented framework-based software development: problems and experi­ences2000In: ACM Computing Surveys, ISSN 0360-0300 , Vol. 32, no 1, p. 3-8Article in journal (Refereed)
  • 157. Bosch, Jan
    et al.
    Molin, Peter
    Mattsson, Michael
    Bengtsson, PerOlof
    Fayad, Mohamed E.
    Framework Problems and Experiences1999In: Building Applica­tion Frameworks: Object Oriented Foundations of Framework Design / [ed] Fayad, M. E.; Schmidt, D. C.; Johnson, R. E., Wiley & Sons , 1999, p. 55-82Chapter in book (Other academic)
  • 158. Branca, Luca
    et al.
    Johansson, Stefan J.
    Using Multi-agent System Technologies in Settlers of Catan Bots2007Conference paper (Refereed)
  • 159. Brandt, Patrik
    Information in use: Aspects of information quality in workflows2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is founded on the global growth of the service sector and its significance for society as a whole and for the individual human being. In the last decade, technology has changed the way services are created, developed and delivered in remarkable ways. The focus of the thesis is technology in interplay with humans and organisations and the socio-economic-technical systems in which digital services play a central role. Challenges addressed by the thesis include requirement analysis, trustworthy systems, in- and outsourcing aspects, the proper understanding of information and its use in real world applications. With this in mind, the thesis presents a configurable methodology with the purpose to quality assure service oriented workflows found in socio-economictechnical systems. Important building blocks for this are information types and service supported workflows. Our case study is of a call centre-based business called AKC (Apotekets kundcentrum). AKC constitutes a part of the Cooperation of Swedish Pharmacies (Apoteket AB). One of their main services offered to Swedish citizens is the handling of incoming questions concerning pharmaceutical issues. We analysed the interactive voice response system at AKC as a starting point for our investigations and we suggest a more flexible solution. We regard a socio-economic-technical system as an information ecology, which puts the focus on human activities supported by technology. Within these information ecologies, we have found that a Service Oriented Architecture (SOA) can provide the flexible support needed in an environment with a focal point on services. Input from information ecologies and SOA also enables a structured way of managing in- and outsourcing issues. We have also found that if we apply SOA together with our way of modelling a Service Level Agreement (SLA), we can coordinate high-level requirements and support system requirements. In the dissertation, we propose three attributes closely linked to information quality: • Trustworthiness of the source • Protection against falsification of information • The receiver’s competence to use obtained information in the appropriate and intended way. The first attribute concerns the assessment of a source’s trustworthiness. The second regards the ascertainment that the information has not been falsified on its way from the source to the receiver. These two attributes can be related to the classic CIA-model for information security. The last attribute can be related to the use of information, and this thesis also focuses on this issue. As a result, we propose a set of guidelines which represent our approach towards developing quality assured systems. We also present two main types of validation for service oriented workflows: validation of requirement engineering and validation of business processes.

  • 160. Brandt, Patrik
    et al.
    Wennberg, Louise
    Informatisk forskning om riskanalysprocess applicerad på Apoteket AB:s kundcenterverksamhet2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Denna licentiatuppsats skildrar en studie av hur introduktionen av kundcenterverksamhet inom Apoteket AB påverkar utförandet av och arbetet med organisationens riskanalys. De två kundcenter som har introducerats i verksamheten fungerar idag som centrala noder, till vilka samtal kopplas som vanligtvis tidigare besvarades på något av landets 900 apotek. Vidare kan kundcentren erbjuda ytterligare kommunikationskanaler såsom fax, e-post och Internet via Apotekets webbplats i syfte att öka tillgängligheten för kunder och övriga intressenter samt att möta de sätt som information eftersöks i dagens informationssamhälle. Integrationen med Apotekets övriga system erbjuder korta svarstider och en möjlighet för kunderna att handha större delar av sina ärenden själva. Vad som dock lätt förbises är hur informationssäkerheten påverkas vid införande av kundcenterverksamhet och åtföljande integrering, samt vilka hot och risker detta innebär för organisationen och indirekt även för kunderna. Ett värdefullt verktyg som används i informationssäkerhetsarbetet med att försöka förutse samt inringa en så stor andel hot och risker som möjligt är riskanalysen. Idag märks också en ökad medvetenhet bland allmänheten vad gäller risker och hot relaterade till bland annat Internet, både vad anbelangar privat och företags/organisationsrelaterad användning. Detta har medfört att företag och organisationer har insett vikten av att bedriva ett aktivt informationssäkerhetsarbete för att kunna leverera lämplig säkerhetsnivå. Det är av stor vikt att kunderna kan känna samma tillit till företagets eller organisationens varumärke som tidigare, oavsett vilka organisatoriska eller tekniska förändringar som har skett internt. En viktig del i processen med att uppnå detta är riskanalysen och de resultat den frambringar. I denna studie har vi uppmärksammat behovet av att anpassa den i organisationen använda riskanalysen till den tillkomna kundcenterverksamheten. Detta behov är stort, särskilt då kommunikationskanalerna är av olika natur vilket gör att deras respektive hotbilder är olika. Det breda spektrumet av hotbilder måste således uppmärksammas i riskanalysen och arbetet med denna. En utveckling av den omkringliggande miljön skall också återspeglas i riskanalysen som följaktligen behöver vara dynamisk. Betydelsen av att placera riskanalysen i ett holistiskt sammanhang tilldelas stor vikt i denna studie.

  • 161. Bratthall, Lars
    et al.
    Wohlin, Claes
    Is it Possible to Decorate Graphical Software Design and Architecture Models with Qualitative Information?: An Experiment2002In: IEEE Transactions on Software Engineering, ISSN 0098-5589, E-ISSN 1939-3520, Vol. 28, no 12, p. 1181-1193Article in journal (Refereed)
    Abstract [en]

    Software systems evolve over time and it is often difficult to maintain them. One reason for this is often that it is hard to understand the previous release. Further, even if architecture and design models are available and up to date, they primarily represent the functional behaviour of the system. To evaluate whether it is possible to also represent some non-functional aspects, an experiment has been conducted. The objective of the experiment is to evaluate the cognitive suitability of some visual representations that can be used to represent a control relation, software component size and component external and internal complexity. Ten different representations are evaluated in a controlled environment using 35 subjects. The results from the experiment show that it representations with low cognitive accessibility weight can be found. In an example, these representations are used to illustrate some qualities in an SDL block diagram. It is concluded that the incorporation of these representations in architecture and design descriptions is both easy and probably worthwhile. The incorporation of the representations should enhance the understanding of previous releases and hence help software developers in evolving and maintaining complex software systems.

  • 162. Brazier, Frances
    et al.
    Cornelissen, Frank
    Gustavsson, Rune
    Jonker, Catholijn M.
    Lindeberg, Olle
    Polak, Bianca
    Treur, Jan
    Compositional verification of a multi-agent system for one-to-many negotiation2004In: Applied intelligence (Boston), ISSN 0924-669X, E-ISSN 1573-7497, Vol. 20, no 2, p. 95-117Article in journal (Refereed)
    Abstract [en]

    Verification of multi-agent systems hardly occurs in design practice. One of the difficulties is that required properties for a multi-agent system usually refer to multi-agent behaviour which has nontrivial dynamics. To constrain these multi-agent behavioural dynamics, often a form of organisational structure is used, for example, for negotiating agents, by following strict protocols. The claim is that these negotiation protocols entail a structured process that is manageable with respect to analysis, design and execution of such a multi-agent system. In this paper this is shown by a case study: verification of a multi-agent system for one-to-many negotiation in the domain of load balancing of electricity use. A compositional verification method for multi-agent systems is applied that allows to (1) logically relate dynamic properties of the multi-agent system as a whole to dynamic properties of agents, and (2) logically relate dynamic properties of agents to properties of their subcomponents. Given that properties of these subcomponents can be verified by more standard methods, these logical relationships provide proofs of the dynamic properties of the multi-agent system as a whole.

  • 163.
    Bräutigam, Martin
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Gustafsson, Mikael
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Aktiv reglering av rörelse i ryggmärg2006Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Researchers in neurophysiology in Lund have undertaken measurements of the spinal cord in rats where the movement of the spinal cord due to blood flow and breathing has proved to be a major obstacle in their research. Except from manufacturing electrodes specialized for the task, an idea has been to reduce the effect of the motion by moving a table on which the object is placed, in a compensating manner. To further explore this idea, cooperation with an engineer at the department of Neurophysiology, Lund University, has been the subject of this thesis. A table movable in three directions was constructed. DC-motors controlling an eccentric were chosen as actuators for the motion control. A circuit for direct analogue control of DC-motors implementing proportional, integrating and differentiating stages aimed for standard PID control was built. The circuit allows current control to avoid overload of the motor as well as balancing of DC-noise from the amplifier stages. Recordings of the spinal cord motion as well as heart and breathing signals was done with a laser-vibrometer. Signal analysis was performed to investigate the suitability of reference-based feed forward control with the filtered-x LMS algorithm. The analysis showed poor result for this method.

  • 164.
    BUDDA, SARATH CHANDRA REDDY
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    RATCHA, SREEKANTH
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Estimation of Direction of Arrival and Beamforming in Adaptive Array Antennas2005Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    In recent years there has been a rapid growth in the number of wireless users, particularly in the area of mobile communications. This rapid growth in mobile communications demands for more system capacity through efficient utilization of frequency spectrum and also keeping the Interference as low as possible. In today’s Radio resource management, Adaptive array antennas have an important role in increasing the system capacity and controlling the interference in mobile communications. Adaptive array antenna is an antenna system, which uses spatially separated antennas called array antennas and processes the received signals with a digital signal processor. Simply speaking these array antennas can reduce the co channel interference and effectively utilize the bandwidth by steering a high gain in the direction of interest and low gains in the undesired directions, technically this is called adaptive beamforming. This adaptive beamforming enables the base station to form narrow beam towards desired user and nulls towards the interfering user, hence improving the signal quality.

  • 165.
    Bukhari, Syed Majid Ali Shah
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Khan, Inayat Ullah
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    SWOT Analysis of IP Multimedia Sub System Security Authentication Schemes2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    SWOT analysis is performed on IMS security authentication schemes to demonstrate the effectiveness of each schemes in terms of multiple parameters and associated dependencies for users and network operators. Due to SWOT tool we have been able to describe strengths, weakness, opportunities and threats in each authentication scheme separately. The analysis performed mostly based on the state of art studies, SWOT tool itself approximates authentication schemes but in the discussion chapter we illustrated clearly what is necessary to adopt individually between Non SIM and SIM base authentication schemes. It will help MOBICOME project and network operators to choose the most appropriate authentication technology/ technologies for design and implementation.

  • 166.
    Buqinca, Alban
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Zangana, Ala
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    TelMe Mobile2009Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [sv]

    Dagens teknik har bidragit till att mobiltelefonens användningsområden har expanderat avsevärt de senaste åren. Detta har lett till att alltfler mobila tjänster har dykt upp på marknaden. Uppgiften i detta examensarbete består i att utveckla en version anpassad för mobiltelefoner av den existerande produkten TelMe, som är en webbtjänst för vikarietillsättning inom olika verksamheter. Den mobilanpassade versionen kommer att gå under namnet TelMe Mobile. Problemställningen var att implementera de väsentliga funktionerna i produkten med avsikt för att göra dessa tillgängliga för mobiltelefoner. För att hitta en lösning till problemställningen har följande frågeställningar formulerats; hur kan webbtjänsten TelMe anpassas till en mobiltelefon, hur kan innehållet presenteras i en mobiltelefon på ett användarvänligt sätt, hur kan dataflödet reduceras samt hur implementeras de tekniska lösningarna för TelMe Mobile? Eftersom utveckling för mobiltelefoner kräver ett helt annat tankesätt, samlades information om mobila webbapplikationer från officiella organisationer. Begränsningar i mobiltelefoner som t.ex. skärmstorlek, bandbredd och förhållandevis underlägsen hårdvara innebär att webbapplikationen måste vara enkel och inte resurskrävande. Med hänsyn till ovanstående restriktioner måste TelMe designas om och följa denna enkla struktur. Webbapplikationen måste ha en enkelkolumnig layout på grund av mobiltelefoners relativt mindre skärmstorlekar. På grund av den begränsade bandbredden och minneskapaciteten för mobiltelefoner är det viktigt att datamängden inte är för stor. För att reducera datamängden för varje sida måste antalet rader med information minskas. Användning av bilder för layouten kan bidra till en ökning av datamängden, därför bör mindre eller inga bilder utnyttjas. Den tekniska lösningen för TelMe Mobile har implementerats som en separat sida för mobiltelefoner medan TelMe är avsedd för datorer. Implementeringen genomfördes med hjälp av XHTML Mobile Profile 1.0 och eFrog Builder. W3C:s riktlinjer för mobil webbutveckling har följts för att säkerställa TelMe Mobiles kompatibilitet med ett brett utbud av mobiltelefoner. Kompatibiliteten kan dock inte garanteras med alla mobiltelefoner på grund av den breda variationen av mobila plattformar. TelMe Mobile har testats på ett antal olika mobiltelefoner med de vanligast förekommande plattformarna. Webbapplikationen har även testats på Opera Mini, som är en populär tredjepartswebbläsare med bra stöd för den mobila webben. Mobilvänligheten för TelMe Mobile har validerats på http://ready.mobi, vilket kontrollerar webbapplikationen gentemot W3C:s standarder för mobil webbutveckling.

  • 167.
    Burman, Niklas
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Nilsson, Kristofer
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Koordination? -FULLT! 5 platser (11.45) kollat med Turistbyrån2008Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Uppsatsen behandlar hur två organisationer samarbetar och koordinerar deras kooperativa arbete med hjälp av en artefakt. De två organisationerna är Marinmuseum och Turistbyrån där deras kooperativa arbete handlar om att skapa guidade turer tillsammans. Vi har jobbat mot målgruppernas målsättningar, behov och krav för att hitta det ultimata stödet för deras verksamhet. Syftet är att förmedla förståelse för hur organisationerna idag använder artefakten i deras gemensamma arbete, baserat på intervjuer och observationer. Huvudfrågorna i vår studie har varit: Hur kan vi som utvecklare kan stödja de två olika organisationernas samarbetsmöjligheter och förbättra koordinationen i det fall då de använder denna artefakt, deras pappersbaserade bokningslista som primär informationsplats? Hur kan denna artefakt ersättas utan att tappa dess koordinations och interaktions förmågor samt flexibilitet? Studien har visat att den pappersbaserade artefakten, deras bokningslista, innefattar många positiva egenskaper som vid digitalisering måste tas hänsyn till. Denna artefakt har vi valt att kalla för koordinationsartefakt för att belysa dess koordinationsegenskaper. Med vår studie vill vi framhäva den markanta skillnaden med ett system som är anpassat efter verksamheten istället för att verksamheten är anpassad efter systemet.

  • 168.
    Butt, Asim
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Identifying Factors Affecting Software Process Improvement during Change2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Software process improvement is an important activity which starts when an organization plans to enhance/purify the capabilities of its ongoing processes. When improvement or change is planned or started, there are a number of factors which originate and affect the effectiveness of software process improvement. If they are not identified and dealt with proper expertise, they can leave adverse effects in the form of low effectiveness, high cost, low quality etc. Such factors change the intensity or the expected results of software process improvement. It is very important to understand and highlight these factors in order to make the process improvement effective and efficient in an organization during change. This master thesis is written to answer the research questions which elaborate the understanding of software process improvement and factors affecting the software process improvement during change in an organization. Moreover, a systematic review is also performed in identifying and prioritizing the factors which affect the software process improvement activity in change. The outcomes of this research can be helpful in understanding the factors affecting SPI during change.

  • 169.
    Butt, Rehman
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Performance Comparison of AI Algorithms: Anytime Algorithms2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Commercial computer gaming is a large growing industry, that already has its major contributions in the entertainment industry of the world. One of the most important among different types of computer games are Real Time Strategy (RTS) based games. RTS games are considered being the major research subject for Artificial Intelligence (AI). But still the performance of AI in these games is poor by human standards because of some broad sets of problems. Some of these problems have been solved with the advent of an open real time research platform, named as ORTS. However there still exist some fundamental AI problems that require more research to be better solved for the RTS games. There also exist some AI algorithms that can help us solve these AI problems. Anytime- Algorithms (AA) are algorithms those can optimize their memory and time resources and are considered best for the RTS games. We believe that by making AI algorithms anytime we can optimize their behavior to better solve the AI problems for the RTS games. Although many anytime algorithms are available to solve various kinds of AI problems, but according to our research no such study is been done to compare the performances of different anytime algorithms for each AI problem in RTS games. This study will take care of that by building our own research platform specifically design for comparing performances of selected anytime algorithms for an AI problem

  • 170.
    Butt, Rehman
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Performance Comparison of AI Algorithms: Anytime Algorithms2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Commercial computer gaming is a large growing industry that already has its major contributions in the entertainment industry of the world. One of the most important among different types of computer games are Real Time Strategy (RTS) based games. RTS games are considered being the major research subject for Artificial Intelligence (AI). But still the performance of AI in these games is poor by human standards due to some fundamental AI problems those require more research to be better solved for the RTS games. There also exist some AI algorithms those can help us solve these AI problems. Anytime- Algorithms (AA) are algorithms those can optimize their memory and time resources and are considered best for the RTS games. We believe that by making AI algorithms anytime we can optimize their behavior to better solve the AI problems. Although many anytime algorithms are available to solve various kinds of AI problems, but according to our research no such study is been done to compare the performances of different anytime algorithms for an AI problem in RTS games. This study will take care of that by building our own research platform specifically design for comparing performances of our selected anytime algorithms for an AI problem.

  • 171.
    Bäcklin, Anna
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Jansson, Peter
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Designing ePeer: Using Participatory Design to bridge cultural differences when developing computer software2004Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [en]

    This thesis presents a study that was conducted within a project, the purpose of which was development of a software application (ePeer) for students at Mbarara University of Science and Technology (MUST). ePeer is a tool for gaining information about Youth Sexual and Reproductive Health and will be used in a peer education project which is currently being set up in Mbarara. The study presented in this report aims at designing the interface of ePeer. Our intention was to develop a design that would suit the future users of ePeer. Achieving that involved learning about user expectations and bridging the cultural differences between us, the software developers, and the future users. In order to meet the user expectations we decided to get students at MUST involved in the design process of ePeer’s interface. Two methods were used to accomplish that, namely mock-ups and evaluations. The mock-up sessions provided us with a number of prototypes of ePeer’s interface, created by the students. The evaluation of three applications, with functionality similar to ePeer, resulted in a list of application features that were most appreciated by the students. By analyzing the outcome of the mock-up and evaluation sessions we managed to learn about the students’ expectations concerning ePeer’s content, functionality and layout. Basing on that analysis we suggested a design of ePeer’s interface. The design was positively evaluated by representatives of the future users.

  • 172. Bäumer, Martin
    et al.
    Siedler, Patrick
    Torkar, Richard
    Tomaszewski, Piotr
    Damm, Lars-Ola
    Feldt, Robert
    Predicting Fault Inflow in Iterative Software Development Processes: An Industrial Evaluation2008Conference paper (Refereed)
  • 173.
    Carimo, Rossana
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Evaluation of the UML profile for QoS from the user perspective2007Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Addressing Quality of Service and specification of quality attributes has been gaining a growing importance in the software engineering area. The research presented in this study investigates different approaches to specification of Quality of Service. UML profile for Quality of Service is one of the standards of the Quality of Service specification and is described in the QoS specification context. The research aim of this thesis is the evaluation of the UML profile for Quality of Service against the following criteria: expressiveness, reusability, understandability, applicability and tool support, as well as further comparison of the profile with other Quality of Service specification languages. To perform that, several tasks and activities were conducted, such as a survey on different QoS specification languages, an examination of the UML profile for Quality of Service, the formulation of the evaluation criteria, and the appliance of the criteria in the evaluation and comparison processes. This study is performed from the perspective of readers and users of the profile that are not UML experts but have sufficient knowledge of UML in terms of software systems analysis and design. The context of the UML profile and Quality of Service aspects include basic concepts of the UML 2.0 and Quality of Service which will be described along the thesis. The main contribution of the thesis is the evaluation of the UML profile for Quality of Service against a set of criteria, followed by explanations on the contents of the profile and how Quality of Service is specified within it. The presented comparison of the UML profile and other Quality of Service specification languages could be the basis for a user to decide what language to use in a particular situation. This study can be comprehended as a starting point for further evaluation of the UML profile and its comparison with other quality specification languages.

  • 174. Carlsson, Bengt
    Hot och svek— Säkerhet hos människor och datorer2006Collection (editor) (Other academic)
  • 175. Carlsson, Bengt
    et al.
    Baca, Dejan
    Software Security Analysis: Execution Phase Audit2005Conference paper (Refereed)
    Abstract [en]

    Code revision of a leading telecom product was performed, combining manual audit and static analysis tools. On average, one exploitable vulnerability was found for every 4000 lines of code. Half of the located threats in the product were buffer overflows followed by race condition, misplaced trust, and poor random generators. Static analysis tools were used to speed up the revision process and to integrate security tests into the overall project process. The discussion analyses the effectiveness of automatic tools for auditing software. Furthermore, the incorporation of the software security analysis into the development process, and the results and costs of the security analysis is discussed. From the initial 42 workdays used for finding all vulnerabilities, approximately 16 days were needed for finding and correcting 91,5 % of the vulnerabilities. So, proportionally small investments improve the program code security by integrating an automatic auditing tool into the ordinary execution of source code revision.

  • 176. Carlsson, Bengt
    et al.
    Boldt, Martin
    Security Analysis of the Swedish Road User Charging System2008Conference paper (Refereed)
    Abstract [en]

    A security analysis based on probabilities, consequences and costs resulted in a priority ranking for physical, logical and human threats for the proposed Swedish road user charging system using a smartcard solution. Countermeasures are described as top prioritized, highly prioritized, average prioritized and low prioritized and compared to operational errors. Logical countermeasures like encryption and local buffering are most cost efficient to implement and different human threats are most difficult to deal with. In the end a security solution based on dynamical safety mechanisms is suggested.

  • 177. Carlsson, Bengt
    et al.
    Davidsson, Paul
    Jacobsson, Andreas
    Johansson, Stefan J.
    Persson, Jan A.
    Security Aspects on Inter-Organizational Cooperation Using Wrapper Agents2005Conference paper (Refereed)
    Abstract [en]

    The significance of electronic information exchange in interorganizational cooperation is well-known. We will here focus on the particular requirements of SMEs. We describe a general “wrapper agent” solution based on open source freeware that makes it possible (in principle) for any business system to exchange information with any other business system. It has been successfully applied in a pilot study involving two companies in a transport chain using different business systems. We also suggest further improvements by addressing security and privacy issues as well as an extended, possibly dynamic, set of involved companies and higher levels of cooperation.

  • 178. Carlsson, Bengt
    et al.
    Jacobsson, Andreas
    On Contamination in Information Ecosystems2005Conference paper (Refereed)
    Abstract [en]

    On the Internet, digitally active small and medium sized enterprises (SME) face numerous security risks. When SMEs join networks, business ideas and malicious activities may interfuse. E-mail marketing, remote control and information gathering are replaced by spam, virulent programs and spyware. In this paper, we use the concepts of information ecosystems to describe a security model where, as a background, humans are presumed to act as Machiavellian beings, i.e., behaving selfishly. Based on this notion, we analyse behaviours initiated by network contaminants and their effects to an entire ecosystem. The contribution of this paper is the security model, which permits a comprehensive view on the risk environment in virtual networks (like the digital SME community).

  • 179. Carlsson, Bengt
    et al.
    Jacobsson, Andreas
    Security Consistency in Information Ecosystems: Structuring the Risk Environment on the Internet2006In: Journal of Information System Security, ISSN 1551-0123, E-ISSN 1551-0808, Vol. 2 , no 1, p. 3-26Article in journal (Refereed)
    Abstract [en]

    The concepts of information ecosystems and multi agent systems are used to describe a security consistency model where, as a background, humans are presumed to act as Machiavellian beings, i.e. behaving selfishly. Based on this notion, we analyze behaviors initiated by network contaminants derived from the groupings marketing, espionage and malice, and their effects to an entire ecosystem. The contribution of this paper is a security consistency model, which illustrates a comprehensive and systemic view of the evolutionary risk environment in information networks.

  • 180. Carlsson, Bengt
    et al.
    Jönsson, Ingemar
    The success of cooperative strategies in the iterated prisoner's dilemma and the chicken game2007In: Scalable Computing: Practice and Experience, ISSN 1895-1767, E-ISSN 1895-1767, Vol. 8, no 1, p. 87-100Article in journal (Refereed)
  • 181. Carlsson, Bengt
    et al.
    Jönsson, Ingemar
    Clark, Keith
    Describing Cryptobiosis as a Time Based Protection System Using Petri Nets2008Conference paper (Refereed)
    Abstract [en]

    Cryptobiosis represents the state of a living organism when it shows no visible signs of metabolic life, but maintains a capacity to return to an active, metabolic state. This peculiar state, although known from a wide variety of organisms, has received little attention from a theoretically biological perspective. A description based on a Petri net setting and a time based security model is proposed. In order to protect against a prolonged exposure time, the pathways for chemical reactions involved must fulfil their actions during a limited detection and response time to fulfil the protected state of entering/leaving cryptobiosis.

  • 182. Carlsson, Bengt
    et al.
    Jönsson, Ingemar
    Clark, Keith
    Describing Cryptobiosis as a Time Based Protection System using Petri Nets2008Conference paper (Refereed)
    Abstract [en]

    Cryptobiosis represents the state of a living organism when it shows no visible signs of metabolic life, but maintains a capacity to return to an active, metabolic state. This peculiar state, although known from a wide variety of organisms, has received little attention from a theoretically biological perspective. A description based on a Petri net setting and a time based security model is proposed. In order to protect against a prolonged exposure time, the pathways for chemical reactions involved must fulfil their actions during a limited detection and response time to fulfil the protected state of entering/leaving cryptobiosis.

  • 183.
    Carlsson, Josefin
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Johansson, Madeleine
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Att täcka en obekant yta med Spanning Tree Covering, Topologisk Täckande Algoritm, Trilobite2005Independent thesis Basic level (degree of Bachelor)Student thesis
    Abstract [sv]

    Det har blivit mer och mer vanligt med ny, datoriserad teknik i hemmen. Fler människor har ett allt stressigare liv och inte längre samma tid att ta hand om det egna hemmet. Behovet av en hjälpande hand med hushållsarbete har blivit allt större. Tänk själv att komma hem från jobbet eller skolan och så har golvet blivit skinande rent utan att Ni knappt har behövt göra någonting! Det finns idag flera olika robotar på marknaden för detta ändamål. En av dessa är den autonoma dammsugaren, som är det vi inriktat vår uppsats på. I huvudsak är uppsatsen inriktad på mjukvaran, som kan användas i en autonom dammsugare. Vi har valt att titta närmare på två stycken sökalgoritmer, som kan användas av autonoma mobila robotar, exempelvis en autonom dammsugare, som har i uppdrag att täcka en hel obekant yta. Dessa algoritmer är Spanning Tree Covering (STC) och ”A Topological Coverage Algorithm”, också kallad ”Landmark-based World Model” (fritt översatt till Topologisk Täckande Algoritm, TTA). Vi har också undersökt hur ett av Sveriges största märken på marknaden för autonoma dammsugare, nämligen Electrolux Trilobite ZA1, klarar sig i test. Vi har även analyserat testet med Trilobiten och jämfört detta med antaget beteende hos Trilobiten ifall den hade varit implementerad med sökalgoritmerna STC eller TTA. Hur fungerar sökalgoritmerna? Hur kan en autonom dammsugare hitta på en hel obekant yta? Hur beter sig Electrolux Trilobite ZA1? Täcker de alla en obekant yta? Är de effektiva?

  • 184. Carlsson, Patrik
    et al.
    Constantinescu, Doru
    Popescu, Adrian
    Fiedler, Markus
    Nilsson, Arne A.
    Delay Performance in IP Routers2004Conference paper (Refereed)
    Abstract [en]

    The main goals of the paper are towards an understanding of the delay process in best-effort Internet for both non-congested and congested networks. A dedicated measurement system is re-ported for delay measurements in IP routers, which follows specifications of the IETF RFC 2679. The system is using both passive measurements and active probing. Dedicated application-layer software is used to generate UDP traffic with TCP-like characteristics. Pareto traffic models are used to generate self-similar traffic in the link. The reported results are in the form of several impor-tant statistics regarding processing delay of a router, router delay for a single data flow, router delay for more data flows as well as end-to-end delay for a chain of routers. We confirm results reported earlier about the fact that the delay in IP routers is generally influenced by traffic characteristics, link conditions and, at some extent, details in hardware implementation and different IOS releases. The delay in IP routers usually shows heavy-tailed characteristics. It may also occasionally show extreme values, which are due to improper functioning of the routers.

  • 185. Carlsson, Patrik
    et al.
    Fiedler, Markus
    Nilsson, Arne A.
    Modelling of Ethernet Traffic on Multiple Timescales2004Conference paper (Refereed)
    Abstract [en]

    Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this paper we use such a model. The model operates on matching multiple moments of the bit rate at several timescales. In order to match the model parameters to measured traffic, five methods have been developed. We use this to model three different links; the BCpOct89 Bellcore trace, an Internet access link and an ADSL link. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex.

  • 186.
    Cazorla, Hector Villena
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Multiple Potential Fields in Quake 2 Multiplayer2006Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    This thesis may be interesting for developers within video game industry, people who design the behaviour of agent systems, or those interested in complex robotic control systems. What potential fields give to the world of AI is a new way to implement the behaviour of the agents, giving weights to all the elements in the world, so the agent can decide if making some action deserves the cost, the combination of several potential fields is what makes this technique so efficient. An agent was created applying this technique. Implemented as a client application, the agent used the Quake protocol to connect and communicate with the server. Some tests were run on the model concerning the different functionalities a gamer agent should implement. The model turned out to be a success in a virtual environment like quake 2. Taking care of all the entities in the map and environmental factors, the agent is able to keep his state in balance, move to the most interesting positions and be able to face combat situations. The implementation is clean and mathematical oriented. Using algorithms as the heart of the model, we make the code lightweight in comparison with old bot models.

  • 187.
    Cedergren, Joakim
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Assisted GPS for Location Based Services2005Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    The mobile operators are seeking for opportunities to create differentiation and increase profit. One powerful way is to provide personalized mobile services. A good example of personalisation is by location. Services based on position are called Location Based Services – LBS. To realise LBS, some sort of positioning method is needed. The two most common positioning methods today are Global Positioning System - GPS and network based positioning. GPS is not fully suited for LBS because you need an additional handset to receive the satellite signals. In network positioning however, you only need a mobile phone, but on the other hand, the accuracy is far less, only between 100 metres up to several kilometres. What technology would be a good positioning technology for location based services? Could A-GPS be such technology? A-GPS is a positioning system which uses the same satellites as GPS, but besides that, it also uses a reference network. The reference network tracks the receiver and the satellites. It also makes some of the heavy calculations that the handsets are doing in the GPS system. That makes the A-GPS receivers less power consuming and more suited to be implemented into mobile phones. Furthermore, A-GPS are more sensitive, meaning that it easier can receive signals when using indoor, for example. The question is if A-GPS technology holds its promises? Does A-GPS really work well in mobile phones? Is the accuracy and availability as good as the theory says and is it possible to implement an own, well working, location based service into an A-GPS mobile phone?

  • 188.
    Chakraborty, Joyraj
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    J.V.K.C., Varma
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Erman, Maria
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    ANFIS based Opportunistic power control for cognitive radio in spectrum sharing2013Conference paper (Refereed)
    Abstract [en]

    Cognitive radio is an intelligent technology that helps in resolving the issue of spectrum scarcity. In a spectrum sharing network, where secondary user can communicate simultaneously along with the primary user in the same frequency band, one of the challenges is to obtain balance between two conflicting goals that are to minimize the interference to the primary users and to improve the performance of the secondary user. In our paper we have considered a primary link and a secondary link (cognitive link) in a fading channel. To improve the performance of the secondary user by maintaining the Quality of Service (Qos) to the primary user, we considered varying the transmit power of the cognitive user. For this we proposed ANFIS based opportunistic power control strategy with primary user's SNR and primary user's interference channel gain as inputs. By using fuzzy inference system, Qos of primary user is adhered and there is no need of complex feedback channel from primary receiver. The simulation results of the proposed strategy shows better performance than the one without power control.

  • 189.
    Chaudhry, Fazal-e-Abbas
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Speaker Separation Investigation2007Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    This report describes two important investigations which formed part of an overall project aimed at separating overlapping speech signals. The first investigation uses chirp signals to measure the acoustic transfer functions which would typically be found in the speaker separation project. It explains the behaviour of chirps in acoustic environments that can be further used to find the room reverberations as well, besides their relevance to measuring the transfer functions in conjunction with speaker separation. Chirps that have been used in this part are logarithmic and linear chirps. They have different lengths and are analysed in two different acoustic environments. Major findings are obtained in comparative analysis of different chirps in terms of their cross-correlations, specgrams and power spectrum magnitude. The second investigation deals with using automatic speech recognition (ASR) system to test the performance of the speaker separation algorithm with respect to word accuracy of different speakers. Speakers were speaking in two different scenarios and these were nonoverlapping and overlapping scenarios. In non-overlapping scenario speakers were speaking alone and in overlapping scenario two speakers were speaking simultaneously. To improve the performance of speaker separation in the overlapping scenario, I was working very close with my fellow colleague Mr. Holfeld who was improving the existing speech separation algorithm. After cross-examining our findings, we improved the existing speech separation algorithm. This further led to improvement in word accuracy of the speech recognition software in overlapping scenario.

  • 190.
    Cheema, Rukhsar Ahmad
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Irshad, Muhammad Jehanzeb
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Issues and Optimization of UMTS Handover2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    UMTS is an emerging cell phone technology and it is basically another name for 3G mobile communication systems. It provides an enhanced range of multimedia services like video conferencing and high speed internet access. Sometimes UMTS is marketed as 3GSM emphasizing the both 3G nature and GSM standards which it was designed to succeed. UMTS is also European term for wireless systems based on the IMT-2000 standards. To utilize various merits in mobile telecommunication system which consist of various radio access networks, UMTS as Third Generation wireless technology utilizes a wideband CDMA or TD/CDMA transceiver and also cover large area. Handover is basically a function which continues the communication between users without any gaps when the hardware goes to a place where it finds no network coverage. When we talk in terms of cellular communications systems, handover is a process which is referred to the transfer of a connection from one cell to another. Handover time is generally between 200 and 1,200 milliseconds (ms), which accounts for the delay. In this thesis we are going to find the reasons for these factors which affect the Quality of service of handover. The main focus of this research is to study the some factors which really affect the handover phenomenon in UMTS that basically affect the overall quality of mobile network. For this we intend to find the solution for problems which born during the handover. Handover provides the mobility to users which are the main theme of wireless technology and it is also make the interoperability between different network technologies.

  • 191. Chen, Jiandan
    A Multi Sensor System for a Human Activities Space: Aspects of Planning and Quality Measurement2008Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    In our aging society, the design and implementation of a high-performance autonomous distributed vision information system for autonomous physical services become ever more important. In line with this development, the proposed Intelligent Vision Agent System, IVAS, is able to automatically detect and identify a target for a specific task by surveying a human activities space. The main subject of this thesis is the optimal configuration of a sensor system meant to capture the target objects and their environment within certain required specifications. The thesis thus discusses how a discrete sensor causes a depth spatial quantisation uncertainty, which significantly contributes to the 3D depth reconstruction accuracy. For a sensor stereo pair, the quantisation uncertainty is represented by the intervals between the iso-disparity surfaces. A mathematical geometry model is then proposed to analyse the iso-disparity surfaces and optimise the sensors’ configurations according to the required constrains. The thesis also introduces the dithering algorithm which significantly reduces the depth reconstruction uncertainty. This algorithm assures high depth reconstruction accuracy from a few images captured by low-resolution sensors. To ensure the visibility needed for surveillance, tracking, and 3D reconstruction, the thesis introduces constraints of the target space, the stereo pair characteristics, and the depth reconstruction accuracy. The target space, the space in which human activity takes place, is modelled as a tetrahedron, and a field of view in spherical coordinates is proposed. The minimum number of stereo pairs necessary to cover the entire target space and the arrangement of the stereo pairs’ movement is optimised through integer linear programming. In order to better understand human behaviour and perception, the proposed adaptive measurement method makes use of a fuzzily defined variable, FDV. The FDV approach enables an estimation of a quality index based on qualitative and quantitative factors. The suggested method uses a neural network as a tool that contains a learning function that allows the integration of the human factor into a quantitative quality index. The thesis consists of two parts, where Part I gives a brief overview of the applied theory and research methods used, and Part II contains the five papers included in the thesis.

  • 192. Chen, Jiandan
    et al.
    Khatibi, Siamak
    Kulesza, Wlodek
    Planning of a Multi Stereo Visual Sensor System Depth Accuracy and Variable Baseline Approach2007Conference paper (Refereed)
  • 193. Chen, Jiandan
    et al.
    Khatibi, Siamak
    Kulesza, Wlodek
    Planning of a Multi Stereo Visual Sensor System for a Human Activities Space2007Conference paper (Refereed)
  • 194. Chen, Jiandan
    et al.
    Khatibi, Siamak
    Wirandi, Jenny
    Kulesza, Wlodek
    Planning of a Multi Sensor System for Human Activities Space – Aspects of Iso-disparrity Surface2007Conference paper (Refereed)
    Abstract [en]

    The Intelligent Vision Agent System, IVAS, is a system for automatic target detection, identification and information processing for use in human activities surveillance. This system consists of multiple sensors, and with control of their deployment and autonomous servo. Finding the optimal configuration for these sensors in order to capture the target objects and their environment to a required specification is a crucial problem. With a stereo pair of sensors, the 3D space can be discretized by an iso-disparity surface, and the depth reconstruction accuracy of the space is closely related to the iso-disparity curve positions. This paper presents a method to enable planning the position of these multiple stereo sensors in indoor environments. The proposed method is a mathematical geometry model, used to analyze the iso-disparity surface. We will show that the distribution of the iso-disparity surface and the depth reconstruction accuracy are controllable by the parameters of such model. This model can be used to dynamically adjust the positions, poses and baselines lengths of multiple stereo pairs of cameras in 3D space in order to get sufficient visibility and accuracy for surveillance tracking and 3D reconstruction. We implement the model and present uncertainty maps of depth reconstruction calculated while varying the baseline length, focal length, stereo convergence angle and sensor pixel length. The results of these experiments show how the depth reconstruction uncertainty depends on stereo pair’s baseline length, zooming and sensor physical properties.

  • 195.
    Chen, Rongrong
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Zhu, Min
    Blekinge Institute of Technology, School of Engineering, Department of Signal Processing.
    Birth Density Modeling in Multi-target Tracking Using the Gaussian Mixture PHD Filter2008Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    A recently established method for multi-target tracking which both estimates the time-varying number of targets and their states from a sequence of observation sets in the presence of data association uncertainty, detection uncertainty, noise and false alarms is the probability hypothesis density (PHD) recursion. The approach involves modeling the respective collections of targets and measurements as random finite sets and to propagate the posterior intensity, which is a first order statistic of the random finite set of targets, in time. A closed form solution to the PHD filter recursion for multi-target tracking is provided by the Gaussian Mixture Probability Hypothesis Density filter (GM-PHD filter), whose posterior intensity function is estimated by a sum of weighted Gaussian components, including means, weights and covariances that can be propagated analytically in time. Besides the GM-PHD filter algorithm implementation, choose the probability density function for representing target births in GM-PHD recursion and true target trajectory generation to get best tracking performance is a challenge and is the purpose of this thesis work. One reference to judge the performance of the algorithm is the target detection time, as given in this thesis.

  • 196.
    Cherif, Redha
    Blekinge Institute of Technology, School of Engineering, Department of Systems and Software Engineering.
    Software Process Simulation Modelling: A Multi Agent-Based Simulation Approach2008Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    In this research we present one of the first actual applications of Multi Agent-Based Simulation (MABS) to the field of software process simulation modelling (SPSM). Although a few previous applications were attempted, we explain in our literature review how these failed to take full advantage of the agency paradigm. Our research resulted in a model of the software development process that integrates performance, cognition and artefact quality, for which we built a common simulation framework to implement and run MABS and System Dynamics (SD) simulators upon the same integrated models. Although it is not possible to fully verify and validate implementations and models like ours, we used a number of verification and validation techniques to increase our confidence in these. Our work is also quite unique in that it compares MABS to SD in the context of SPSM. Here, we uncovered quite interesting properties of each simulation approach and how MABS, for example, is "risk averse" when compared to SD. In our discussion section we also present a number of lessons learned regarding the two simulation paradigms as well as various shortcomings in the models we adopted and our own.

  • 197.
    CHETACHI, UMUNNA CHRISTIAN CHEZZ
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Security and Performance Analysis of Topology-Based Intrusion Detection System in Ad Hoc Networks2009Independent thesis Advanced level (degree of Master (Two Years))Student thesis
    Abstract [en]

    As Wireless ad-hoc Networks are becoming an increasingly emerging technology taking a centre stage in exciting research areas which has attracted many research attentions in communication systems, the need for efficient intrusion detection techniques to enhance network security and privacy has gained significant prominence. Intrusion detection systems(IDS) in ad- hoc networks provides an effective method to improve the security, energy efficiency of transmission nodes allowing better spatial reuse of the wireless channel and control over network resources in order to optimize node security and the transmit power thereby maintaining network connectivity. However these global properties have been falsified due to lack of appropriate intrusion detection system leading to severe network failures which is the bane of next generation ad-hoc networks. In this thesis, we investigate few wireless ad-hoc security attacks and vulnerabilities relative to topology control schemes and evaluate their performance under hostile environments. We propose a novel Distributed Intrusion Detection System (DIDS) that incorporates rule- based cluster topology relevant to both Wireless sensor networks (WSNs) and Mobile ad hoc networks (MANETs) to determine their security/performance in application- specific environments. Our DIDS draws inferences of intrusion by comparing anomalous patterns from packet traces of transmit and receive signal powers, ratio of packet arrival rates and anomaly in radio receiver packet power thresholds using buffer window count. Hence we evaluate our intrusion detection mechanism on a jammer attack and observe the effect on the network throughput. Our approach is simulated using the OPNET® simulator. Simulation results show that the detection capabilities of our scheme under a denial of service (DoS) (jammer) attack, increases the bit error rates, increase in transmit delay responses and considerable decrease in both the signal to noise powers and the average network throughput due to the presence of jammer attack which forms the baseline for our analysis required to maintain energy efficiency and improve security in ad hoc network.

  • 198. Chevul, Stefan
    On Application-Perceived Quality of Service in Wireless Networks2006Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wireless and Mobile Internet have changed the way people and businesses operate. Communication from any Internet access point, including wireless networks such as UMTS, GPRS or WLAN has enabled organizations to have a mobile workforce. However, networked applications such as web, email, streaming multimedia etc. rely upon the ability of timely data delivery. The achievable throughput is a quality measure for the very task of a communication system, which is to transport data in time. Throughput is thus one of the most essential enablers for networked applications. While in general, throughput is defined on network or transport level, the application-perceived throughput reflects the Quality of Service from the viewpoints of the application and user. The focus of the thesis is on the influence of the network on the applicationperceived Quality of Service and thus the user perceived experience. An analysis of application based active measurements mimicking the needs of streaming applications is presented. The results reveal clear influence of the network on the application-perceived Quality of Service seen from variations of application-perceived throughput on small time scales. Results also indicate that applications have to cope with considerably large jitter when trying to use the nominal throughputs. It was observed that the GPRS network had considerable problems in delivering packets in the downstream direction even when the nominal capacity of the link was not reached. Finally, the thesis discusses the suitability of wireless networks for different mobile services, since the influence of the network on the application-perceived Quality of Service is of great significance when it comes to customer satisfaction. Therefore, application-perceived Quality of Service in wireless networks must also be considered by the mobile application programmer during the application development.

  • 199. Chevul, Stefan
    et al.
    Isaksson, Lennart
    Fiedler, Markus
    Karlsson, Johan
    Lindberg, Peter
    Measurement of application-perceived throughput of an E2E VPN connection using a GPRS network2005Conference paper (Refereed)
    Abstract [en]

    N/A

  • 200. Chevul, Stefan
    et al.
    Karlsson, Johan
    Isaksson, Lennart
    Fiedler, Markus
    Lindberg, Peter
    Strandén, Lars
    Measurements of Application-Perceived Throughput in DAB, GPRS, UMTS and WLAN Environments2005Conference paper (Refereed)
    Abstract [en]

    Communication services are expected to deliver the desired information in a timely manner without challenging the user’s patience. The corresponding offers by networks are reflected in user- or applications-perceived throughput, which is measured end-to-end for different mobile and wireless networks, namely Digital Audio Broadcast (DAB), General Packet Radio Service (GPRS), Universal Mobile Telecommunication Systems (UMTS), and Wireless Local Area Networks (WLAN). The measurements are based on passive monitoring of throughput statistics for active test traffic and reveal amongst others different kinds of changes of traffic burstiness induced by mobile up- and downlinks and by buffering, respectively. The results will be used for seamless communication, i.e. automatic network selection within the project PIITSA (Personal Information for Intelligent Transport Systems through Seamless communications and Autonomous decisions) aiming at maintaining user-perceived performance and security at the desired levels while keeping communication cost as small as possible.

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