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  • 51.
    Gidensköld, Carl Henrik
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Webbaserat system för kundstatistik: Hemsida24 Analytics2010Självständigt arbete på grundnivå (högskoleexamen), 5 poäng / 7,5 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Den här rapporten är baserad på ett examensarbete som är gjort för Hemsida24 där uppgiften var att skapa ett webbaserat system för att grafiskt visa statistik om deras kunder. Det skapade statistiksystemet har fått namnet Hemsida24 Analytics.I rapporten redovisas hur ovan nämna statistikverktyg har kommit till, samt hur det fungerar. Kundstatistiken visas på ett stilrent sätt med hjälp av amCharts flashbaserade grafer. Baserat på information från Hemsida24:s databas beräknades kundstatistiken och visades därefter i grafer.

    Programmeringen av Hemsida24 Analytics har i största hand gjorts objektorienterat i PHP. Utöver PHP har Zend Framework, MVC, MySQL, HMTL, CSS och jQuery haft en viktig roll under projektets gång.

    I graferna finns möjligheten att visa framtida prognoser. För att räkna ut prognoser för graferna används både linjära ekvationer och andragradsekvationer.

    I rapporten redovisas det slutgiltiga resultatet i jämförelse med projektplaneringen och en tidigare framtagen skiss. Det ges även förslag på eventuell fortsatt utveckling av Hemsida24 Analytics.

  • 52.
    Gustafsson, Mattias
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Odd, Oliver
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Virtual Reality Data Visualization: Concepts, technologies and more2018Självständigt arbete på grundnivå (högskoleexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Datavisualisering (DV) kan ses som ett viktigt verktyg för kommunikation och dataanalys, speciellt när stora mängder data behandlas. Visuell representation kan främja observationen av trender och mönster samt förståelsen av datan. För närvarande används tvådimensionella displayer huvudsakligen för datavisualisering, både i två och tre dimensioner (2D och 3D). Emellertid är tvådimensionella displayer begränsade i 3D-visualisering eftersom de inte möjliggör äkta djupseende, och täcker inte observatörens fulla synfält (Field Of View (FOV)). Ett alternativ tillvägagångssätt är att använda Virtual Reality (VR), vilket tillhandahåller en omslutande och interaktiv 3D-miljö. VR har huvudsakligen används för spel och simulerad träning. Däremot börjar nya användningsområden uppstå då VR teknologin har blivit mer prisvärd. Ett användningsområde är VR för DV, vilket var det huvudsakliga syftet för det här arbetet. För att uppnå syftet utfördes en litteraturstudie för att identifiera teknologier och definitioner, hårdvaru- och mjukvaruteknologier, tekniker och exempel inom området av DV och VR. Dessutom, för att exemplifiera DV genom VR, utvecklades ett prototypsystem. Vilket implementerades genom  Unity 3D, en av de ledande spelmotorerna. För att visualisera den utvecklade VR-miljön användes ett HTC Vive Head Mounted Display (HMD). Den utvecklade prototypen kan visualisera data från ett lokalt dataset genom ett spridningsdiagram med 3 axlar, i VR. I den virtuella miljön som skapas av systemet tillåts användaren att välja attribut från datasetet för att sedan visualisera dessa genom det tredimensionella spridningsdiagrammet. När datan väl är visualiserad, kan användaren använda de handhållna kontrollerna för att flytta, rotera, luta och skala grafen. Uppnådda resultat indikerar på omslutning och interaktion som de huvudsakliga fördelarna av DV genom VR.

  • 53.
    Hajirostam, Siavash
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Evaluation of Storage Area Network (SAN) security and performance2013Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Due to growing the number of Information Technology (IT) users all around the world, consequently the amount of data that needs to be stored is increasing day by day. Single attached disks and old storage technologies cannot manage the storing these amounts of data. Storage Area Network (SAN) is a distributed storage technology to manage the data from several nodes in centralize place and secure. This thesis investigates how SAN works, the file system  and protocols that are used in implementation of SAN. The thesis also investigate about other storages technologies such as Network Attached Storage (NAS) and Direct Attached Storage (DAS) to figure out the advantages and disadvantages of SAN, The main focus of the thesis project is on identifying the security vulnerabilities in SAN such as possible attacks in different SAN protocols. The thesis finally identifies the performance factors in SAN to figure out how to improve the performance with respect to security solutions aimed to enhance the security level in SAN.

  • 54.
    Haque, Md Ansarul
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Hossain, Md Delwar
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Technology Survey of Wireless Communication for In-vehicle Applications2013Självständigt arbete på avancerad nivå (magisterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Currently, wireless communication technologies are expected to be widely employed for in-vehicle communication where in-vehicle communication is built upon the interactions of different parts inside the vehicle. This communication is to enable a variety of applications for driver and passenger needs.  To have improved driving assistance, development of in-vehicle applications is very much needed. At present, intelligent systems inside the vehicle are mostly dominated by the wired technologies. The possibilities of wireless communication have inspired us and made an opportunity to analyse replacements for wired communication within a vehicle. In this connection, the scope of our thesis is to define the in-vehicle applications which are preferred by the wireless technologies, to define the applications using wired technologies which could be replaced by the wireless technologies and to identify those applications which are difficult to implement by the wireless technologies.

     

    In-vehicle wired networks; and problems of these wired networks, along with several existing applications, have been discussed at the initial stage of this thesis for the purpose of having a clear understanding. After that, existing In-vehicle wireless applications and several challenging applications have also been studied. Studies have been done on the most important wireless technologies with their respective specifications. The requirement of establishing wireless communication has also been explained. Finally, an analysis has been done according to the requirements of the applications and verification of their possible reliance on the wireless technologies.

     

    In a brief, comparable studies have been done among the wireless technologies to assess their current and future fitness for In-vehicle applications. The thesis concludes with some recommendations regarding when wireless technologies might be suitable for some in-vehicle applications to replace the wired technologies.

     

  • 55.
    H.Daryani, Sara
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Taslimi, Pouria
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Integrated Security by using MPLS-VPN for Retail-Banking Network: Case study Mehr bank, Iran2010Självständigt arbete på avancerad nivå (magisterexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The studied application area is a private bank with different branches located in different provinces around the country. There was not integrated security solution to provide communication among different branches. Some of these branches could communicate through the satellite and the others could communicate through a different technology, such as asynchronous transfer mode (ATM).

    Different bank security policies were applied and maintained for different branches separately. In addition, the number of branches is expected to grow during coming year in each province.

    The old topology was partial mesh and it could not support enough redundancy in case of disruption. If a connection between two branches failed, other branches might lose their connectivity as well. In addition, it could not achieve optimum routing.

    Providing integrated quality of service (QoS) for the wide area network (WAN) by using different technologies is not easy to achieve, and it causes so many problems for the system. The bank uses a variety of protocols for different applications, depending on its demand, so the new applied technology should not depend on protocols, or at least should support different protocols at a same time. In the old technology, the bank was responsible for granting availability and connectivity maintenance. Providing proper bandwidth is an important aspect in the bank scenario and for the old technology; supplying enough bandwidth was costly.

    As mentioned above, the old applied technology was dependent upon different protocols. Therefore, packets in different open system interconnection layers (OSI layers) would have to check thoroughly to find the source/ destination address, data and so on, to reach the correct destination. This might cause security problems for entire system. In addition, processing packet in each layer of the OSI model is time consuming.

    One important aspect for the retail-banking scenario is considering all features of the security domain, such as security policy, information security, physical security, access level control, integrated security for the system and so on. Some features of the security domain in this project were not covering completely, such as integrated information security, merged security policy, and integrated physical security for the system.

    In this project, all mentioned problems are solved by implementing a specific communication technology which can overcome the problems above. This technology supports multiple protocols, and it provides fast and secure communication. It can also cover redundancy and it does not cost as much as previous technologies like ATM and satellite. Easy provisioning is one feature of this technology. In this technology, the service provider is responsible for granting availability and connectivity maintenance.

    The mentioned features of the security domain, which were not covered by the old technology, will be covered by a proper, integrated security solution. The IP-based physical security systems provide centralized monitoring and they can define a merged security policy for all different branches around the country. Specific, pre-defined scenarios are created for different events in different situations.

  • 56.
    Heimfarth, Tales
    et al.
    Federal University of Lavras, Brazil.
    Freitas, Edison Pignaton de
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Netto, Ivayr Farah
    Federal University of Lavras, Brazil.
    Correia, Luiz H. A.
    Federal University of Lavras, Brazil.
    Pereira, Carlos Eduardo
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Ferreira, Armando Morado
    Military Institute of Engineering, Rio de Janeiro, Brazil.
    Wagner, Flávio Rech
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Larsson, Tony
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Enhanced pheromone-based mechanism to coordinate UAVs and WSN nodes on the ground2010Ingår i: INFOCOMP Journal of Computer Science, ISSN 1807-4545, E-ISSN 1982-3363, Vol. 9, nr 2, s. 75-84Artikel i tidskrift (Refereegranskat)
  • 57.
    Heimfarth, Tales
    et al.
    Computer Science Department, Federal University of Lavras, Lavras, Brazil.
    Freitas, Edison Pignaton de
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Pereira, Carlos Eduardo
    Institute of Informatics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Ferreira, Armando Morado
    Defense Engineering Graduate Program, Military Institute of Engineering, Rio de Janeiro, Brazil.
    Wagner, Flavio Rech
    Institute of Informatics, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Larsson, Tony
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Experimental Analysis of a Wireless Sensor Network Setup Strategy Provided by an Agent-Oriented Middleware2011Ingår i: Advanced Information Networking and Applications (AINA), 2010 24th IEEE International Conference on: proceedings, Los Alamitos, Calif.: IEEE Computer Society, 2011, Vol. 0, s. 820-826Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents simulation results of a setup strategy for wireless sensor networks, based on an agent-oriented middleware. A great problem that has to be tackled in sensor networks is how to setup them to provide the data required from the user with a minimal overhead. Having this goal in mind, the proposed approach abstracts the network setup as missions, which are handled within the network by intelligent agents that disseminate and divide the work related to the missions. Several experiments using this approach are provided, showing its efficiency and the low overhead that it imposes to the network.

  • 58.
    Henriksson, Christopher
    Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap.
    PrePresentia: An appealing way to turn stage fright into stage delight2017Självständigt arbete på grundnivå (kandidatexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Vi har alla varit nervösa inför en muntlig presentation. Detta gäller allt från korta grupparbeten i grundskolan till Examensarbeten på Högskolan, eller ännu större i arbetslivet. Att vara måttligt nervös är önskvärt, då vi människor presterar bäst när vi är lite spända.

    Var går gränsen från måttligt nervös till rent obehag och talångest? Detta är olika för oss alla, men problemet ökar med kraven. Talångesten kan leda till depression, vilket höjer risken att gå in i väggen. Detta är ett område som jag har haft problem med i stort sett hela livet, därför väljer jag det som examensarbete!

    PrePresentia är en applikation för Apples smartphones och surfplattor. Applikationen kombinerar funktioner för talövning med analys av ljud och puls. Användaren kopplar upp pulsmätaren (Apple Watch) mot applikationen och kan på så vis avgöra skillnaden mellan vilopuls innan presentation och den aktiva pulsen efteråt. Applikationen ska hjälpa till, likt idrottarna som analyserar puls och prestation för att förbättra sig. Utöver detta analyseras även talet och en tipslista/guide finns med i applikationen. Övning ger efterallt färdighet! /Christopher Henriksson

  • 59.
    Hoang, Hoai
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Hagström, Ulrik
    Kallerdahl, Anders
    Switched real-time Ethernet with earliest deadline first scheduling - protocols and traffic handling2002Ingår i: Proceedings: International Parallel and Distributed Processing Symposium : April 15-19, 2002, Ft. Lauderdale, Florida, USA, Los Alamitos, Calif.: IEEE Computer Society , 2002, s. 94-99, artikel-id 1016477Konferensbidrag (Refereegranskat)
    Abstract [en]

    There is a strong interest of using the cheap and simple Ethernet technology for industrial and embedded systems. This far, however, the lack of real-time services has prevented this change of used network technology. This paper presents enhancements to full-duplex switched Ethernet for the ability of giving throughput and delay guarantees. The switch and the end-nodes controls the real-time traffic with Earliest Deadline First (EDF) scheduling on the frame level. No modification to the Ethernet standard is needed in the network that supports both real-time and non-real-time TCP/IP communication. The switch is responsible for admission control where feasibility analysis is made for each link between source and destination. The switch broadcasts Ethernet frames regularly to clock synchronize the end nodes and to implement flow control for non-real-time traffic.

  • 60.
    Hoang, Hoai
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Kallerdahl, Anders
    Hagström, Ulrik
    Switched real-time Ethernet with earliest deadline first scheduling - protocols and traffic handling2002Ingår i: Parallel and Distributed Computing Practices, ISSN 1097-2803, Vol. 5, nr 1, s. 105-115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a strong interest of using the cheap and simple Ethernet technology for industrial and embedded systems. This far, however, the lack of real-time services has prevented this change of used network technology. This paper presents enhancements to full-duplex switched Ethernet for the ability of giving throughput and delay guarantees. The switch and the end-nodes control the real-time traffic with Earliest Deadline First (EDF) scheduling on the frame level. No modification to the Ethernet standard is needed in the network that supports both real-time and non-real-time TCP/IP communication. The switch is responsible for admission control where feasibility analysis is made for each link between source and destination. The switch broadcasts Ethernet frames regularly to clock synchronize the end nodes and to implement flow control for non-real-time traffic. We have characterized the performance of the network in terms of channel acceptance ratio by simulations with different number of nodes connected to the switch.

  • 61.
    Hoang, Hoai
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Larsson, Anders
    Olsson, Richard
    Bergenhem, Carl
    Deadline first scheduling in switched real-time Ethernet - deadline partitioning issues and software implementation experiments2002Ingår i: Euromicro RTS 2002: 14th Euromicro Conference on Real-Time Systems : proceedings : 19-21 June, 2002, Vienna, Austria, Los Alamitos, Calif.: IEEE Computer Society , 2002, s. 68-71Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents work on a switched Ethernet network extended to allow for earliest deadline first (EDF) scheduling. We show by example that asymmetric deadline partitioning between the links of a real-time channel can increase the utilization substantially, still not violating the real-time guarantees. We also report measurements on a software implementation of the switch on an ordinary PC.

  • 62.
    Hoang, Hoai
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Karlsson, Stefan
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Minimum EDF-feasible deadline calculation with low-time complexity2004Ingår i: RTSS 2004 WIP Proceedings, The 25th IEEE International Real-Time Systems Symposium, Lisbon, Portugal, Dec. 5-8, 2004, 2004Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a method for calculating the minimum EDF-feasible deadline. The algorithm targets periodic tasks with hard real-time guarantees, that are to be feasibly scheduled with EDF (Earliest Deadline First). The output is the smallest possible deadline required for feasibility, of the task most recently requested. The good thing with our algorithm is that it has the same timecomplexity as the regular EDF feasibility test, when deadlines are not assumed to be equal to the periods of the periodic tasks.

  • 63.
    Islam, Mohammad Shahidul
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Mehdi, Syed Nasir
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    How Different QoS Mechanisms Affect VoIP QoS Metrics2010Självständigt arbete på avancerad nivå (magisterexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Voice over Internet Protocol (VoIP) has become a key technology of communication. Our work has been a practical implemenation of different scenarios to show that VoIP voice quality can be improved by adopting certain Quality of Service(QoS) measures such as classification, marking or queuing. It has been discussed that different QoS metrics like delay, packet loss and jitter could affect the voice quality of VoIP. To reduce the negative affects, one option is to implement certain QoS mechanisms with some set of configurations. For this purpose, Cisco IP phones have been configured in our topology with routers, switches, traffic generators, end stations and VoIP quality monitoring software called VQmanager. Tests have been divided into two sets. In one test a fixed bandwidth of 70 kbps is set while in the other test a random bandwidth is set with trafic generators unleashing packets of traffic. In both these tests further scenarios with configurations are worked out. They include no QoS, Auto Qos and Customized Qos mechanisms. Results have been indicative of top performance by the Customized QoS mechanism, in both sets of tests, followed by Auto QoS and no QoS mechanisms. It has been observed that a customized scenario could be a particular configuration to any organization’s needs and that will have the lowest delay, jitter and packet loss which are the main QoS metrics that impact the voice quality of VoIP. It  can be fundamentally composed of classification of voice, data or web-traffic, marking and queuing depending upon the need of the organization. It is finally suggested to carry more tests in companies to get more data for analysis

  • 64.
    Jiang, Chun hui
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Mao, Yu jiao
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Mindstorm2011Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Since the mindstorm kit is widely used by students and beginners, demand of a commercial-free integrated embedded working environment turns up. With its help the limitation on working place and complexity of programming can be reduced.  The aim of this project is to use a combination of commercial-free softwares as an embedded working environment. The environment can deal with the mindstorm kit applications directly. In order to show the successful generation of the commercial-freesoftware's project an inverted pendulum is set up. Open source firmware of NXT-G is used to provide basic interface for invoking the functions in NXT master brick. Accelerometer is working as the sensor. The main dynamic controller falls on the PD controller to keep inverted pendulum in vertical and static state. As a result the inverted pendulum programmed in this working environment can keep balance for a couple of seconds.

  • 65.
    Jin, Yin
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Digital Jukebox2011Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This bachelor's project uses the Spotify API (Application Programming Interface) to implement a new application called SpotBox, a “digital jukebox”. As it is known, the traditional jukebox has disappeared from the market. There are many reasons for this, such as the limitation of storage capacity and the update frequency of music is not timely. This project proposes to apply the digital technology to build a new jukebox system. The idea is to build an application based on Spotify to run in an ordinary computer that could control the incoming of the coins and the selection of the music. This new version of the jukebox, the digital jukebox, would be deployed in pubs and discos.The development utilized C# as the programming language and the operation system is Microsoft Windows.The method of the project has 3 steps. The first step is the application requirements‟ analysis. This step identifies and analyses the requirements of the application to work as a digital jukebox and the additional functions based on the Spotify.The second step is the study about the Spotify API (Application Programming Interface). This is necessary step to verify what is possible to implement from the identified requirements.Finally, the work was concluded by implementing the required functionalities, as well as a enhancing the graphical interface. The graphical interface combined with these functionalities composes an application prototype.As for the main result, the application was fully developed with the minimum required functionality and interface. Secondary results can be named as the report of the possibilities that allowed by the Spotfy API together with the complete requirement analysis of the functionalities that were outside the scope of the intended prototype implementation.

  • 66.
    Johansson, Christian
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Nilsson, Robin
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    RAM-minnets kontaminering vid tillämpning av forensiska verktyg2011Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Denna rapport behandlar ett specifikt område inom IT-forensik och informationssäkerhet. Då en berörd part behöver agera i ett skarpt läge, kan kunskaperna om volatilt minne vara avgörande. I takt med att IT-brott har ökat dramatiskt, har det också bidragit till en enorm utveckling inom de forensiska ramarna. IT-forensikerns handlingar är av avgörande karaktär då minnet förändras kontinuerligt, därför eftersträvas minimala förändringar på systemet.

    Ett datorsystem är utrustat med ett fysiskt minne vars syfte är att temporärt lagra information då det är aktivt. Detta minne kan vara en rik informationskälla ur ett forensiskt perspektiv. Volatilt minne är uppbyggt av binärkod som går att analysera med hjälp av verktyg. Idag finns det ett stort utbud av verktyg för allmänheten och myndigheter, därför begränsas rapporten med inriktning mot kommersiella metoder.

    För att effektivisera det praktiska utförandet, tillämpas virtualisering som underlättar påvisning av konsistent datautvinning. Vid experimenterande av volatilt minne erhölls framgångsrika resultat där det gick att fastställa förändringar i minnesallokeringen. Då ett program exekveras, resulterar det i märkbara förändringar som går att urskilja i det fysiska minnet. När verktyget sedan har utfört sina givna instruktioner, går det att tolka den procentuella skillnaden mellan minnes-dumparna. Detta bidrog till de förutbestämda målen.

    Det fysiska minnet är ett relativt nytt och outforskat tekniskt område. Valmöjligheten för en minnesutvinning kan innefatta allt från hårdvaru- till mjukvarulösningar där tyngden på denna rapport baseras på mjukvarulösning. Alla IT-forensiker bör få upp ögonen för denna informationstillgång som kan vara nyckeln till framgång under live-respons.

  • 67.
    Johansson, Sebastian
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Sundström, Peter
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Utvinning och analys av positionsdatafrån GPS-enheter: Jämförelse av metoder och program2011Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In the field of IT-forensics you may often get to analyze different types of digital devices. One ofthese devices is the GPS navigation system. Nowadays GPS technology is getting more and morepopular and is included more frequently in different types of devices. With this article we want topresent the differenent obstacles and possibilites that a forensic investigator is presented with in thistype of investigation. We will be comparing different software suites and make use of forensic toolssuch as EnCase.The reader should get some understanding of the methods there are for analyzing one of these devicesand what problems that may occur in the investigation process.The article presents how the investigator can use different methods to gain information such as recentroutes, favourite destinations and other information that may be stored on the device. The amountof information stored on the device depends purely on the device modell that is being analyzed.We will present the process of how to aquire and analyse data from four different GPS devices, twomodels from Garmin and two models from TomTom. The data we have aquired is saved favourites,traveled routes and history from phone calls. We have also done a comparison between two softwaresuites, EnCase and Blackthorn2. Our results have varied between the softwares, with both positiveand negative results. The devices from Garmin gave us the best results in this study.

  • 68.
    Johnsson, Dennis
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Bengtsson, Jerker
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Svensson, Bertil
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Two-level Reconfigurable Architecture for High-Performance Signal Processing2004Ingår i: ERSA'04, The 2004 International Conference on Engineering of Reconfigurable Systems and Algorithms: The 2004 International MultiConference in Computer Science and Computer Engineering / [ed] Toomas P. Plaks, Arthens: CSREA Press, 2004, s. 177-183Konferensbidrag (Refereegranskat)
    Abstract [en]

    High speed signal processing is often performed as a pipeline of functions on streams or blocks of data. In order to obtain both flexibility and performance, parallel, reconfigurable array structures are suitable for such processing. The array topology can be used both on the micro and macro-levels, i.e. both when mapping a function on a fine-grained array structure and when mapping a set of functions on different nodes in a coarse-grained array. We outline an architecture on the macro-level as well as explore the use of an existing, commercial, word level reconfigurable architecture on the micro-level. We implement an FFT algorithm in order to determine how much of the available resources are needed for controlling the computations. Having no program memory and instruction sequencing available, a large fraction, 70%, of the used resources is used for controlling the computations, but this is still more efficient than having statically dedicated resources for control. Data can stream through the array at maximum I/O rate, while computing FFTs. The paper also shows how pipelining of the FFT algorithm over a two-level reconfigurable array of arrays can be done in various ways, depending on the application demands.

  • 69.
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Comments on interconnection networks for parallel radar signal processing systems1999Rapport (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    In this report, some high-performance interconnection networks are briefly commented/evaluated against a specific radar signal processing system selected as a general representative system

  • 70.
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Control-channel based fiber-ribbon pipeline ring network1998Ingår i: Fifth International Conference on Massively Parallel Processing: proceedings : June 15-18, 1998, Las Vegas, Nevada, Piscataway, NJ.: IEEE , 1998, s. 158-165Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we propose a control-channel based ring network built up of fiber-ribbon point-to-point links. One of the fibers in each link forms part of the control-channel ring, over which medium access control information is sent immediately before data transmissions. This increases performance of the network. High throughputs can be achieved in the network due to pipelining, i.e., several packets can be traveling through the network simultaneously but in different segments of the ring. The network can meet high performance demands in, e.g., massively parallel signal processing systems, which is shown by example in the paper. Also, real-time demands can be met using slot reserving. The network, called CC-FPR (Control-Channel based Fiber-ribbon Pipeline Ring), can be built today using fiber-optic off-the-shelf components, and a prototype is currently under development. The increasingly good price/performance ratio for fiber-ribbon links indicates a great success potential for the proposed kind of network.

  • 71.
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Fiber-optic interconnection networks for signal processing applications1999Ingår i: Parallel and distributed processing : 11th [sic] IPPS/SPDP '99 workshops held in conjunction with the 13th International Parallel Processing Symposium and 10th Symposium on Parallel and Distributed Processing, San Juan, Puerto Rico, USA, April 12-16, 1999 : proceedings / [ed] José Rolim, Frank Mueller, Albert Y. Zomaya, Fikret Ercal, Stephan Olariu, Binoy Ravindran, Jan Gustafsson, Hiroaki Takada, Ron Olsson and Laxmikant V. Kale, et al., London: Springer-Verlag , 1999, Vol. 1586, s. 1374-1385Konferensbidrag (Refereegranskat)
    Abstract [en]

    In future parallel radar signal processing systems, with high bandwidth demands, new interconnection technologies are needed. The same reasoning can be made for other signal processing applications, e.g., those involving multimedia. Fiber-optic networks are a promising alternative and a lot of work have been done. In this paper, a number of fiber-optic interconnection architectures are reviewed, especially from a radar signal processing point-of-view. Two kinds of parallel algorithm mapping are discussed: (i) a chain of pipeline-stages mapped, more or less directly, one stage per computation node and (ii) SPMD (Same Program Multiple Data). Several network configurations, which are simplified due to the nature of the applications, are also proposed. © Springer-Verlag Berlin Heidelberg 1999

  • 72.
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Fiber-Optic Interconnections in High-Performance Real-Time Computer Systems1997Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Future parallel computer systems for embedded real-time applications,where each node in itself can be a parallel computer, are predicted to havevery high bandwidth demands on the interconnection network. Otherimportant properties are time-deterministic latency and guarantees to meetdeadlines. In this thesis, a fiber-optic passive optical star network with amedium access protocol for packet switched communication in distributedreal-time systems is proposed. By using WDM (Wavelength DivisionMultiplexing), multiple channels, each with a capacity of several Gb/s, areobtained.

    A number of protocols for WDM star networks have recently been proposed.However, the area of real-time protocols for these networks is quiteunexplored. The protocol proposed in this thesis is based on TDMA (TimeDivision Multiple Access) and uses a new distributed slot-allocationalgorithm with real-time properties. Services for both guarantee-seekingmessages and best-effort messages are supported for single destination,multicast, and broadcast transmission. Slot reserving can be used toincrease the time-deterministic bandwidth, while still having an efficientbandwidth utilization due to a simple slot release method.

    By connecting several clusters of the proposed WDM star network by abackbone star, thus forming a star-of-stars network, we get a modular andscalable high-bandwidth network. The deterministic properties of thenetwork are theoretically analyzed for both intra-cluster and inter-clustercommunication, and computer simulations of intra-cluster communicationare reported. Also, an overview of high-performance fiber-opticcommunication systems is presented.

  • 73.
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    High performance fiber-optic interconnection networks for real-time computing systems1999Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Parallel and distributed computing systems become more and more powerful and hence place increasingly higher demands on the networks that interconnect their processors or processing nodes. Many of the applications running on such systems, especially embedded systems applications, have real-time requirements and, with increasing application demands, high-performance networks are the hearts of these systems. Fiber-optic networks are good candidates for use in such systems in the future.

    This thesis contributes to the relatively unexplored area of fiber-optic networks for parallel and distributed real-time computer systems and  suggests and evaluates several fiber-optic networks and protocols. Two different technologies are used in the networks, WDM (Wavelength Division Multiplexing) and fiber-ribbon point-to-point links. WDM offers multiple channels, each with a capacity of several Gbit/s. A WDM star network in which protocols and services are efficiently integrated to support different kinds of real-time demands, especially hard ones, has been developed. The star-of-stars topology can be chosen to offer better network scalability.

    The WDM star architecture is attractive but its future success depends on components becoming more commercially mature. Fiber-ribbon links, offering instead an aggregated bandwidth of several Gbit/s, have already reached the market with a promising price/performance ratio. This has motivated the development and investigation of two new ring networks based on fiber-ribbon links. The networks take advantage of spatial bandwidth reuse, which can greatly enhance performance in applications with a significant amount of nearest downstream neighbor communication. One of the ring networks is control channel based and not only has support for real-time services like the WDM star network but also low level support for, e.g., group communication.

    The approach has been to develop network protocols with support for dynamic real-time services, out of time-deterministic static TDMA systems. The focus has been on functionality more than pure performance figures, mostly on real-time features but also on other types of functionality for parallel and distributed systems. Worst-case analyses, some simulations, and case studies are reported for the networks. The focus has been on embedded supercomputer applications, where each node itself can be a parallel computer, and it is shown that the networks are well suited for use in the radar signal processing systems studied. Other application examples in which these kinds of networks are valuable are distributed multimedia systems, satellite imaging and other image processing applications.

  • 74.
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    High-performance fiber-optic communication networks for distributed computing systems1997Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Interconnection networks have a key role in distributed processing systems of today but to follow the evolution in processing power, new technologies are needed. Multiple-channel fiber-optic communication can solve the emerging demand of bandwidth. New protocols must, however, be used to coordinate the use of multiple high-speed channels. This paper describes protocols and fiber-optic network architectures that are considered to be useful as flexible interconnection networks in future parallel and distributed computing systems. Also, a short overview of system components and system technologies is presented.

  • 75.
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Optical interconnection technology in switches, routers and optical cross connects2003Ingår i: Optical Networks Magazine, ISSN 1388-6916, E-ISSN 1388-6916, Vol. 4, nr 4, s. 20-34Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The performance of data- and telecommunication equipment must keep abreast of the increasing network speed. At the same time, it is necessary to deal with the internal interconnection complexity, which typically grows by N2 or NlogN, where N is the number of ports. This requires new interconnection technologies to be used internally in the equipment. Optical interconnection technology is a promising alternative and much work has already been done. This paper reviews a number of optical and optoelectronic interconnection architectures, especially from a data and telecommunication equipment point of view. Three kinds of systems for adopting optical interconnection technology are discussed: (i) optical cross connects (OXCs), (ii) switches and routers with some kind of burst switching and (iii) switches and routers that redirect traffic on the packet or cell level. The interconnection technologies and architectures are discussed according to their suitability for adoption in the three system types.

  • 76.
    Jonsson, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Optical Interconnection Technology in Switches, Routers and Optical Cross Connects2001Ingår i: International Conference on Parallel Processing Workshops, 2001, IEEE Computer Society , 2001, s. 319-326, artikel-id 951968Konferensbidrag (Refereegranskat)
    Abstract [en]

    The performance of data- and telecommunication equipment must keep up with the increasing network speed. At the same time, one must deal with the internal interconnection complexity, often growing exponentially with the number of ports. Therefore, new interconnection technologies to be used internally in the equipment are needed. Optical interconnection technology is a promising alternative and much work has been done. In this paper, a number of optical and optoelectronic interconnection architectures are reviewed, especially from a data- and telecommunication equipment point-of-view. Three kinds of systems for adoption of optical interconnection technology are discussed: (i) optical cross connects (OXCs), (ii) switches and routers with some kind of burst switching, and (iii) switches and routers which redirect traffic on the packet or cell level. The reviewed interconnection technologies and architectures are discussed according to their suitability of adoption in the three mentioned system types.

  • 77.
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Optical interconnections in parallel radar signal processing systems1999Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Optical interconnection networks is a promising design alternative for future parallel computer systems. Numerous configurations with different degrees of optics, optoelectronics, and electronics have been proposed. In this paper, some of these interconnection networks and technologies are briefly surveyed. Also, a discussion of their suitability in radar signal processing systems is provided, where several different ways of coarse algorithm mapping are considered.

  • 78.
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Two fiber-ribbon ring networks for parallel and distributed computing systems1998Ingår i: Optical Engineering: The Journal of SPIE, ISSN 0091-3286, E-ISSN 1560-2303, Vol. 37, nr 12, s. 3196-3204Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ring networks made of fiber-ribbon point-to-point links are proposed. The first network is a control-channel based network in which one fiber in each link joins with others to form a control-channel ring. This ring improves performance of the network by sending medium access control information immediately before the data transmissions. High throughputs can be achieved in the network due to pipelining, i.e., several packets can travel through the network simultaneously but in different segments of the ring. The network can meet tough performance demands in, e.g., massively parallel signal processing systems, which is shown by example. Also, real-time demands can be met using slot reserving. The network, called CC-FPR (control-channel based fiber-ribbon pipeline ring), can be built today using off-the-shelf fiber optic components. The increasingly good price/performance ratio for fiber-ribbon links indicates a high potential for the success of the proposed kind of networks; a prototype is currently under development. The second network is similar to first except that it divides the network into two subnetworks, one for packet-switched traffic and one for circuit-switched traffic. When the main data flow in the network does not change rapidly, this is a good choice for a simple but powerful network.

  • 79.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    Bergenhem, Carl
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    A class of Fiber-Ribbon Pipeline Ring networks for parallel and distributed computing systems2001Ingår i: PDPTA'2001: Proceedings of the International Conference on Parallel and Distributed Processing Techniques and Applications / [ed] Arabnia, H R, Athens, GA: CSREA Press, 2001, s. 1869-1875Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, three ring networks made up of fiber-ribbon point-to-point links are presented. The first network is a control-channel based network in which one fiber in each link joins with others to form a control-channel ring. This ring improves performance of the network by sending medium access control information immediately before the data transmissions. High throughputs can be achieved in the network due to pipelining, i.e., several packets can be traveling through the network simultaneously but in different segments of the ring. Also, real-time demands can be met using slot reserving. The network, called CC-FPR (Control-Channel based Fiber-ribbon Pipeline Ring), can be built today using off-the-shelf fiber-optic components. The increasingly good price/performance ratio for fiber-ribbon links indicates a high potential for the success of the proposed kind of networks. The second network is similar to the first one except that it divides the network into two sub-networks, one for packet switched traffic and one for circuit -switched traffic. When the main data flow in the network does not change rapidly, this is a good choice of a simple but powerful network. In the third network, the medium access protocol of the first network is exchanged with a one with global deadline scheduling to support best-effort real-time traffic.

  • 80.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Bergenhem, Carl
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Olsson, Jörgen
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Fiber-ribbon ring network with services for parallel processing and distributed real-time systems1999Ingår i: Proc. SNART'99 Real-Time Systems Conference, 1999, s. 46-54Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present how real-time services are implemented in a control-channel based ring network built up of fiber-ribbon point-to-point links. Services for best effort messages, guarantee seeking messages and real-time virtual channels are supported for single destination, multicast and broadcast transmission by the network. Slot-reservation is used for the implementation of real-time virtual channels. High aggregated throughput can be achieved due to pipelining, i.e., data can be transmitted simultaneously in different segments of the ring. An analysis of worst-case latency and deterministic throughput, which are important measures for real-time service implementation, is provided. The network is analyzed for two variants of time-slot organization, one that offers higher throughput and one that offers lower latency in some situations. We also show how the network offers low-level support for parallel computing, i.e.,  barrier-synchronization and global reduction. The control channel is used when realizing these functions, which implies no modification of the original network architecture. Low-level support for reliable transmission is also offered in a similar manner. This includes acknowledge / negative acknowledge and flow-control.

  • 81.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Bergenhem, Carl
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Olsson, Jörgen
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Fiber-ribbon ring network with services for parallel processing and distributed real-time systems1999Ingår i: Proc. ISCA 12th International Conference on Parallel and Distributed Computing Systems (PDCS-99), ISCA , 1999, s. 94-101Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we present how real-time services are implemented in a control-channel based ring network built up of fiber-ribbon point-to-point links. Services for best effort messages, guarantee seeking messages and real-time virtual channels are supported for single destination, multicast and broadcast transmission by the network. Slot-reservation is used for the implementation of real-time virtual channels. High aggregated throughput can be achieved due to pipelining, i.e., data can be transmitted simultaneously in different segments of the ring. An analysis of worst-case latency and deterministic throughput, which are important measures for real-time service implementation, is provided. The network is analyzed for two variants of time-slot organization, one that offers higher throughput and one that offers lower latency in some situations. We also show how the network offers low-level support for parallel computing, i.e.,  barrier-synchronization and global reduction. The control channel is used when realizing these functions, which implies no modification of the original network architecture. Low-level support for reliable transmission is also offered in a similar manner. This includes acknowledge / negative acknowledge and flow-control.

  • 82.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Börjesson, Klas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Legardt, Magnus
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Dynamic time-deterministic traffic in a fiber-optic WDM star network1997Ingår i: Proceedings: Ninth Euromicro Workshop on Real Time Systems, June 11-13, 1997, Toledo, Spain, Piscataway, NJ.: IEEE Computer Society, 1997, s. 25-33, artikel-id 613760Konferensbidrag (Refereegranskat)
    Abstract [en]

    A number of protocols for WDM (Wavelength Division Multiplexing) star networks have been proposed. However, the area of real-time protocols for these networks is quite unexplored. In this paper, a real-time protocol, based on TDM (Time Division Multiplexing), for fiber-optic star networks is presented. By the use of WDM, multiple Gb/s channels are achieved. Services for both guarantee-seeking messages and best-effort messages are supported for single destination, multicast, and broadcast transmission. Slot reserving can be used to increase the time-deterministic bandwidth, while still having an efficient bandwidth utilization due to a simple slot release method. The deterministic properties of the protocol are analyzed and simulation results presented. © 1997 IEEE

  • 83.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Kunert, Kristina
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Towards reliable wireless industrial communication with real-time guarantees2009Ingår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 5, nr 4, s. 429-442Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Increased mobility coupled with a possible reduction of cabling costs and deployment time makes wireless communication an attractive alternative for the automation industry and related application areas. Methods compensating for the high probability of bit errors accompanying wireless transmissions are, however, needed. This is predominantly important in industrial applications with strict reliability and timing requirements, which cannot be met by standard communication protocols as e.g. TCP. In this paper, way of combining retransmissions with real-time worst-case scheduling analysis is presented that can offer both a high grade of reliability and hard real-time support. The presented solution handles one or several retransmission attempts of erroneous data without jeopardizing already guaranteed delay bounds of other packets. A real-time analysis for a full-duplex, asymmetric link, utilizing the novel retransmission scheme and supporting both piggybacked and nonpiggybacked acknowledgements, is provided. A simulation study is presented that evaluates the performance of the retransmission scheme for bit error rates typically experienced in wireless communication. The results clearly indicate a possible reduction of the message error rate by several orders of magnitude.

  • 84.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Kunert, Kristina
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Wired and wireless reliable real-time communication in industrial systems2010Ingår i: Factory Automation / [ed] Javier Silvestre-Blanes, Vienna, Austria: IN-TECH , 2010, s. 161-176Kapitel i bok, del av antologi (Övrigt vetenskapligt)
    Abstract [en]

    In modern factory automation systems, data communication plays a vital role. Different nodes like control systems, sensors and actuators can communicate over a wireless or wired industrial network. The data traffic generated is often scheduled for periodic transmission, where each single message or packet must arrive in time. For this real-time communication, methods have been developed to support communication services with a guaranteed throughput and delay bound for such periodic traffic, but merely under the assumption of error-free communication. However, the possibility for errors in the transmission still exists due to, e.g. noise or interference. A node receiving sensor values from a sensor in the system might then be forced to rely upon an older sensor value from the latest period, possibly leading to inaccuracies in control loops which can compromise the functioning of the system. In safety-critical systems, redundant networks or communication channels are frequently added to cope with errors, leading to more expensive systems. In this chapter, we will describe an alternative approach where erroneous data packets are retransmitted in a way that does not jeopardise any earlier stated real-time guarantees for ordinary transmissions. Using our framework, the reliability of real-time communication can be increased in a more cost-efficient way. We describe in this chapter an overview of our framework for reliable real-time communication, while details of our approach can be found in our earlier publications. In the light of the emerging use of wireless communication, the framework proves to be especially useful due to the high bit error rate inherent to the wireless medium. However, the framework is naturally also attractive for wired communication systems.

  • 85.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Nilsson, Kenneth
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Svensson, Bertil
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    A fiber-optic interconnection concept for scaleable massively parallel computing1995Ingår i: Proceedings of the Second International Conference on Massively Parallel Processing Using Optical Interconnections: October 23 - 24, 1995, San Antonio, Texas, Piscataway, NJ.: IEEE , 1995, s. 313-320Konferensbidrag (Refereegranskat)
    Abstract [en]

    One of the most important features of interconnection networks for massively parallel computer systems is scaleability. The fiber-optic network described in this paper uses both wavelength division multiplexing and a configurable ratio between optics and electronics to gain an architecture with good scaleability. The network connects distributed modules together to a huge parallel system where each node itself typically consists of parallel processing elements. The paper describes two different implementations of the star topology, one uses an electronic star and fiber optic connections, the other is purely optical with a passive optical star in the center. The medium access control of the communication concept is presented and some scaleability properties are discussed involving also a multiple-star topology.

  • 86.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Olin, Ulf
    Optical interconnection technology in switches, routers and optical cross connects2000Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The performance of data- and telecommunication equipment must keep up with the increasing network speed. Moreover, to allow more input and output ports on such equipment, the internal interconnection complexity often grows exponentially with the number of ports. Therefore, new interconnection technologies to be used internally in the equipment are needed. Optic interconnection technology is a promising alternative and a lot of work has been done. In this report, a number of optical and optoelectronic interconnection architectures are reviewed, especially from a data- and telecommunication equipment point-of-view. Three kinds of systems for adoption of optical interconnection technology are discussed: (i) optical cross connects (OXCs), (ii) switches and routers with some kind of burst switching, and (iii) switches and routers which redirect traffic on the packet or cell level. The reviewed interconnection technologies and architectures are discussed according to their suitability of adoption in the three mentioned systems.

    The annex summarises manufacturers of devices required for optical interconnects and backplanes, and needs for optical interconnection technology in future Ericsson systems.

  • 87.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Svensson, Bertil
    Chalmers University of Technology, Gothenburg, Sweden.
    On inter-cluster communication in a time-deterministic WDM star network1997Ingår i: Proc. 2nd Workshop on Optics and Computer Science (WOCS), Geneva, Switzerland, Apr. 1, 1997, 1997, s. 10-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Future real-time applications requiring massively parallel computer systems also put high demands on the interconnection network. By connecting several WDM star clusters by a backbone star, forming a star-of-stars network, we get a modular high-bandwidth network. In this paper we show how to achieve time-deterministic packet switched communication in such networks, even for inter-cluster communication. An analysis of how the deterministic latency and node bandwidth vary with design parameters is presented. We also propose a general clock-synchronization scheme, improving the worst-case latency with up to 33 percentages.

  • 88.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Svensson, Bertil
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Taveniku, Mikael
    Chalmers University of Technology.
    Åhlander, Anders
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Fiber-ribbon pipeline ring network for high-performance distributed computing systems1997Ingår i: Proceedings of the Third International Symposium on Parallel Architectures, Algorithms, and Networks, 1997. (I-SPAN '97), IEEE, 1997, s. 138-143Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper, we propose a high-bandwidth ring network built up with fiber-ribbon point-to-point links. The network has support for both packet switched and circuit switched traffic. Very high throughputs can be achieved in the network due to pipelining, i.e., several packets can be traveling through the network simultaneously but in different segments of the ring. The network can be built today using fiber-optic off-the-shelf components. The increasingly good price/performance ratio for fiber-ribbon links indicates a great success potential for the proposed kind of networks. We also present a massively parallel radar signal processing system with exceptionally high demands on the communication network. An aggregated throughput of tens of Gb/s is needed in this application, and this is achieved with the proposed network.

  • 89.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Wiberg, Per-Arne
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Centrum för forskning om inbyggda system (CERES).
    Wickström, Nicholas
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR Centrum för tillämpade intelligenta system (IS-lab).
    Vision-based low-level navigation using a feed-forward neural network1997Ingår i: Proc. International Workshop on Mechatronical Computer Systems for Perception and Action (MCPA'97), Pisa, Italy, Feb. 10-12, 1997, s. 105-111Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we propose a simple method for low-level navigation for autonomous mobile robots, employing an artificial neural network. Both corridor following and obstacle avoidance in indoor environments are managed by the same network. Raw grayscale images of size 32 x 23 pixels are processed one at a time by a feed-forward neural network. The output signals from the network directly control the motor control system of the robot. The feed-forward network is trained using the RPROP algorithm. Experiments in both familiar and unfamiliar environments are reported.

  • 90.
    Jonsson, Magnus
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Åhlander, Anders
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Taveniku, Mikael
    Chalmers University of Technology.
    Svensson, Bertil
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Time-deterministic WDM star network for massively parallel computing in radar systems1996Ingår i: Proceedings of the Third International Conference on Massively Parallel Processing Using Optical Interconnections: October 27-29, 1996, Maui, Hawaii / [ed] Allan Gottlieb, Los Alamitos, California: IEEE Computer Society Press , 1996, s. 85-93Konferensbidrag (Refereegranskat)
    Abstract [en]

    In massively parallel computer systems for embedded real-time applications there are normally very high bandwidth demands on the interconnection network. Other important properties are time-deterministic latency and services to guarantee that deadlines are met. In this paper we analyze how these properties vary with the design parameters for a passive optical star network, specifically when used in a massively parallel radar signal processing system. The aggregated bandwidth and computational power of the radar system are approximately 45 Gb/s and 100 GOPS, respectively. The analysis is focused on the medium access control protocol, called TD-TWDMA, for the time and wavelength multiplexed network. It is concluded that the proposed network is very well suited to this kind of signal-processing applications. We also present a new distributed slot-allocation algorithm with real-time properties.

  • 91.
    Jorlöv, David
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Utvinning av volatil-data: En jämförelse av olika verktygs påverkan på Windows XP och 7 vid en volatil-data-utvinning2013Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Examensarbetet går ut på att utreda vad verktyg vid volatil-data-utvinning (Reeve & Shipley, 2006) orsakar för förändringar på ett datasystem. Volatil-data är information som försvinner när datasystemet stängs av och kan vara nödvändig t.ex. när man försöker läsa en krypterad hårddisk, då krypteringsnyckeln (Casey, et al., 2011) kan finnas i (Random Access Memory) RAM-minnet som är volatilt. I IT-brottslighetens barndom utvecklades (Brown, 2009) metoder för att påverkan på ett datasystem vid ett beslag skulle bli så liten som möjligt. Detta gjordes för att beviset man får från datasystemet skulle hålla i en rättgång och gick ofta ut på att slå av strömmen på datasystemet. I dagsläget är detta inte alltid möjligt då viktig volatil information kan gå förlorad som t.ex. en krypteringsnyckel från RAM-minnet. Därför är det viktigt att (Blyth, et al., 2008) veta vad verktygen som används vid en volatil-data-utvinning orsakar för förändringar på datasystemet, för att man ska kunna använda sig av det verktyget som orsakar minst förändringar på datasystemet. Dessutom kan man i en rättegång tala om vilka förändringar verktyget orsakade.I examensarbetet har 14 verktyg analyserats på operativsystemen Windows XP och Windows 7. De med samma funktion jämfördes med varandra för att ta reda på vilka som orsakar minst förändringar i datasystemet. Från analysen av verktyg vid volatil-data-utvinning kan man konstatera att verktygen med ett grafiskt gränssnitt skrev betydligt mer till Windowsregistret än kommandoradsbaserade verktyg.

  • 92.
    Khan, Shahzad Hayat
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Badshah, Jehan
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Multicasting in Intra and Inter Domain Networks2011Självständigt arbete på avancerad nivå (magisterexamen), 15 poäng / 22,5 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Multicasting in a network improves the efficiency to deliver an IP packet to multiple clients at the same time. Small to medium sized organizations implement this technology to enhance their network capability, which is otherwise not possible just with normal routing. However, to use this technology, it requires proper network design with tidy resource implementation.Network administrators prefer automatic deployment of multicast technology because it reduces the potential risk of prolonged down time during network troubleshooting. On the other hand, choosing an auto deployment technology could cause malfunctioning in the network. To avoid such malfunctioning, we used two technologies: Auto-RP (Auto- Rendezvous Point) [1] and Bootstrap [2] in our network. A problem that occurs here is that if different domains with similar or different technologies want to share their resources with each other, then regular multicasting cannot connect them for successful communication. Also, if an administrator wishes to provide short and redundant paths within a domain, then these two technologies do not possess the ability to do so.The thesis presents issues in intra-domain and inter-domain multicast networks; it also focuses on Auto-RP (Auto Rendezvous Point) and BSR (Bootstrap Router) which are technologies related to multicasting. This project highlights the importance of multicasting security and will brief the problems associated with these two technologies. It will offer a better solution with a properly implemented design guide. The study uses MSDP (Multicast Source Discovery Protocol) [3] which connects two domains with multicasting capabilities for exchanging the source and providing redundancy in intra- domain. The work implements MBGP (Multicast Border Gateway Protocol) [4] to avoid a situation in which there is no multicast support on one of the service provider(s) end.

    Keywords:Auto-RP (Auto-Rendezvous Point), BSR (Bootstrap Router), MSDP (Multicast Source Discovery Protocol), MBGP (Multicast Border Gateway Protocol)

  • 93.
    Kindberg, Christoffer
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    Kurkinen, Jonas
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE).
    En IT-forensikers kamp mot IT-brottsligheten: En studie om arbetssätt hos polisens IT-forensiker2013Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Användandet av informationsteknik (IT) ökar explosionsartat, idag ligger det i våra dagliga rutiner att använda någon form av IT. Ökningen av användare gör att antalet IT-relaterade brott ökar, d.v.s brott som på ett eller annat sätt involverar IT. Då de IT-relaterade brotten växer i antal blir arbetsbördan för de som säkrar den tekniska bevisningen större, dessa kallas IT-forensiker. Arbetet handlar om hur polisens IT-forensiker arbetar och vilka problem de kan stöta på under en utredning. Resultatet är baserat på fysiska intervjuer och enkäter med en kvalitativ forskningsmetod med semistrukturerade frågor, d.v.s. intervjuer riktade till en person eller en grupp där alla får samma frågor. För att ytterligare förstå vad en IT-forensiker arbetar med återskapades ett autentiskt rättsfall med inriktning på fildelning från Nacka tingsrätt. Ett scenario skapades där den misstänkte i det autentiska rättsfallet överklagar och vi fick som uppgift att verifiera den tidigare bevisningen. Våra resultat visar på att arbetssätten hos de olika polismyndigheterna i grunden är samma med små variationer och att det krävs ett antal specifika egenskaper för att klara av jobbet som IT-forensiker. Samtliga 20 IT-forensiker som deltog tycker att jobbet är spännande och roligt, det är dock inte alltid en dans på rosor då det förekommer en del negativa aspekter.

  • 94.
    Kockum, Henrik
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Persson, John
    Högskolan i Halmstad, Akademin för informationsteknologi.
    Uppgradering av Mingo Matte2018Självständigt arbete på grundnivå (högskoleexamen), 180 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    I dagens samhälle så består 40% av mobilmarknaden av telefoner med 64-bitars support. Sent år 2017 så förmedlade Google att till 2019 så kommer det att krävas att alla applikationer som läggs upp på deras marknad har stöd för 64-bitar. Apple har själva haft detta kravet sedan 2015. Meningen med detta är att maximera prestandan och säkerheten av applikationen och därmed för enheten själv. Detta projekt har som mål att undersöka hur och vad som krävs för att uppgradera en redan befintlig app ”Mingo Matte”, från att endast stödja 32-bitar till 64-bitar. En förundersökning gjordes för att undersöka och utvärdera vilken plattform som passade utvecklingen av projektet bäst. Sedan efter uppdatering av den äldre koden till ny syntax, så blev en ny applikation med 64-bitars stöd skapad. Projektet gavs av företaget Mingo Education och alla deras vinster går mot ”Läkare I Världen”, vilket är en organisation som get sjukvård till de som inte har tillgång till det. 

  • 95.
    Kollreider, Klaus
    et al.
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Fronthaler, Hartwig
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Bigun, Josef
    Högskolan i Halmstad, Akademin för informationsteknologi, Halmstad Embedded and Intelligent Systems Research (EIS).
    Verifying Liveness by Multiple Experts in Face Biometrics2008Ingår i: IEEE Conference on Computer Vision and Pattern Recognition Workshops: CVPR 2008, Anchorage, Alaska, June 23-28, 2008, New York: IEEE Press, 2008, s. 1200-1205Konferensbidrag (Refereegranskat)
    Abstract [en]

    Resisting spoofing attempts via photographs and video playbacks is a vital issue for the success of face biometrics. Yet, the “liveness ” topic has only been partially studied in the past. In this paper we are suggesting a holistic liveness detection paradigm that collaborates with standard techniques in 2D face biometrics. The experiments show that many attacks are avertible via a combination of antispoofing measures. We have investigated the topic using real-time techniques and applied them to real-life spoofing scenarios in an indoor, yet uncontrolled environment.

  • 96.
    Kunert, Kristina
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Architectures and Protocols for Performance Improvements of Real-Time Networks2010Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    When designing architectures and protocols for data traffic requiring real-time services, one of the major design goals is to guarantee that traffic deadlines can be met. However, many real-time applications also have additional requirements such as high throughput, high reliability, or energy efficiency. High-performance embedded systems communicating heterogeneous traffic with high bandwidth and strict timing requirements are in need of more efficient communication solutions, while wireless industrial applications, communicating control data, require support of reliability and guarantees of real-time predictability at the same time. To meet the requirements of high-performance embedded systems, this thesis work proposes two multi-wavelength high-speed passive optical networks. To enable reliable wireless industrial communications, a framework in­corporating carefully scheduled retransmissions is developed. All solutions are based on a single-hop star topology, predictable Medium Access Control algorithms and Earliest Deadline First scheduling, centrally controlled by a master node. Further, real-time schedulability analysis is used as admission control policy to provide delay guarantees for hard real-time traffic.

    For high-performance embedded systems an optical star network with an Arrayed Waveguide Grating placed in the centre is suggested. The design combines spatial wavelength re­use with fixed-tuned and tuneable transceivers in the end nodes, enabling simultaneous transmis­sion of both control and data traffic. This, in turn, permits efficient support of heterogeneous traf­fic with both hard and soft real-time constraints. By analyzing traffic dependencies in this mul­tichannel network, and adapting the real-time schedulability analysis to incorporate these traffic dependencies, a considerable increase of the possible guaranteed throughput for hard real-time traffic can be obtained.

    Most industrial applications require using existing standards such as IEEE 802.11 or IEEE 802.15.4 for interoperability and cost efficiency. However, these standards do not provide predict­able channel access, and thus real-time guarantees cannot be given. A framework is therefore de­veloped, combining transport layer retransmissions with real-time analysis admission control, which has been adapted to consider retransmissions. It can be placed on top of many underlying communication technologies, exemplified in our work by the two aforementioned wireless stan­dards. To enable a higher data rate than pure IEEE 802.15.4, but still maintaining its energy saving properties, two multichannel network architectures based on IEEE 802.15.4 and encompassing the framework are designed. The proposed architectures are evaluated in terms of reliability, utiliza­tion, delay, complexity, scalability and energy efficiency and it is concluded that performance is enhanced through redundancy in the time and frequency domains.

  • 97.
    Kunert, Kristina
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Fibre-Optic AWG Networks Supporting Real-Time Communication in High-Performance Embedded Systems2008Licentiatavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    High-performance embedded systems communicating heterogeneous traffic with high bandwidth and strict timing requirements are in need of more efficient communication solutions. This thesis proposes two multi-wavelength passive optical networks able to meet these demands. The networks are based upon a single-hop star topology with an Arrayed Waveguide Grating (AWG) placed in the centre. The intended application areas for the two networks are short range embedded communication systems like System Area Networks (SANs) and router architectures with electronic queuing. The AWG’s attractive property of spatial wavelength reuse, as well as the combination of fixed-tuned and tuneable transceivers in the end nodes, enables simultaneous control and data traffic transmission. This, in turn, makes it possible to support heterogeneous traffic with both hard and soft real-time constraints.

    Additionally, two Medium Access Control (MAC) protocols, one for each network solution, are developed. Traffic scheduling is centrally controlled by a node, the protocol processor, residing together with the AWG in a hub. All nodes use Earliest Deadline First (EDF) scheduling and communicate with the protocol processor through physical control channels. A case study, including simulations, in the field of Radar Signal Processing (RSP) and simulations using periodic real-time traffic are conducted for the two application areas respectively, showing very good results. Further, a deterministic real-time analysis is conducted to provide throughput and delay guarantees for hard real-time traffic and an increase in guaranteed traffic is achieved through an analysis of existing traffic dependencies in a multichannel network. Simulation results incorporating the traffic dependency analysis indicate a considerable increase in the possible guaranteed throughput of hard real-time traffic.

  • 98.
    Kunert, Kristina
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Improving the scheduling analysis of hard real-time traffic by analyzing traffic dependencies2008Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Support for hard real-time traffic requires throughput guarantees for packets with timing constraints. The deterministic analysis available for real-time communication has its origin in the area of task scheduling in real-time systems and has been mapped onto the communication context. Mapping uniprocessor scheduling techniques directly on a multichannel network with the possibility of concurrent transmissions, however, introduces pessimism to the analysis. This paper presents an approach of successfully increasing the amount of possible guarantees by analyzing traffic interdependencies. By taking into account those traffic interdependencies and integrating concurrent transmissions into the analysis, the amount of throughput guarantees can be increased considerably as shown in our simulations.

  • 99.
    Kunert, Kristina
    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).
    Böhm, Annette
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS).
    AWG-based optoelectronic router supporting both guaranteed and best-effort QoS traffic2005Konferensbidrag (Refereegranskat)
    Abstract [en]

    We present a router architecture with electronic queuing and a passive optical multi-channel network, based upon a single-hop star topology with an Arrayed Waveguide Grating (AWG) at its centre. The AWG’s property of spatial wavelength reuse and both fixed-tuned and tuneable transceivers enable simultaneous control and data transmission. Our proposed medium access control protocol supports traffic differentiation and utilizes EDF (Earliest Deadline First) to schedule the traffic from input ports to output ports on the router. Our simulations show that the router treats QoS (Quality of Service) traffic well.

  • 100.
    Kunert, Kristina
    et al.
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Weckstén, Mattias
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Jonsson, Magnus
    Högskolan i Halmstad, Sektionen för Informationsvetenskap, Data– och Elektroteknik (IDE), Halmstad Embedded and Intelligent Systems Research (EIS), Inbyggda system (CERES).
    Algorithm for the choice of topology in reconfigurable networks with real-time support2007Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Many future embedded systems are likely to contain System-on-Chip solutions with on-chip networks, and to achieve high aggregated throughputs in these networks, a switched topology can be used. For further performance improvements, the topology can be adapted to application demands, either when designing the chip or by run-time reconfiguration between different predefined application modes. In this report, we describe an algorithm for the choice of topology in, e.g., packet-switched on-chip networks, considering the real-time demands in terms of throughput and delay often put on such systems. To further address possible real-time demands, we include a feasibility analysis to check that the application, when mapped onto the system, will behave in line with its real-time demands. With input information about the traffic characteristics, our algorithm creates a topology and generates routing information for all logical traffic channels. In a case study, we show that our algorithm results in a topology that can outperform the use of state of the art topologies for high-performance computer architectures. Although we have targeted for reconfigurable Network-on-Chip architectures, the algorithm can also be used for other systems. Our algorithm gives the opportunity for topology choice at design stage, both for static network topologies and for reconfigurable network topologies that can be reconfigured during run-time.

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