Spelling suggestions: "subject:"datorteknik"" "subject:"datortekniks""
491 |
Partitioned Scheduling of Real-Time Tasks on Multi-core PlatformsNemati, Farhang January 2010 (has links)
<p>In recent years multiprocessor architectures have become mainstream, and multi-core processors are found in products ranging from small portable cell phones to large computer servers. In parallel, research on real-time systems has mainly focused on traditional single-core processors. Hence, in order for real-time systems to fully leverage on the extra capacity offered by new multi-core processors, new design techniques, scheduling approaches, and real-time analysis methods have to be developed.</p><p>In the multi-core and multiprocessor domain there are mainly two scheduling approaches, global and partitioned scheduling. Under global scheduling each task can execute on any processor at any time while under partitioned scheduling tasks are statically allocated to processors and migration of tasks among processors is not allowed. Besides simplicity and efficiency of partitioned scheduling protocols, existing scheduling and synchronization methods developed for single-core processor platforms can more easily be extended to partitioned scheduling. This also simplifies migration of existing systems to multi-cores. An important issue related to partitioned scheduling is distribution of tasks among processors which is a bin-packing problem.</p><p>In this thesis we propose a partitioning framework for distributing tasks on the processors of multi-core platforms. Depending on the type of performance we desire to achieve, the framework may distribute a task set differently, e.g., in an application in which tasks process huge amounts of data the goal of the framework may be to decrease cache misses.Furthermore, we propose a blocking-aware partitioning heuristic algorithm to distribute tasks onto the processors of a multi-core architecture. The objective of the proposed algorithm is to decrease blocking overhead of tasks which reduces the total utilization and has the potential to reduce the number of required processors.Finally, we have implemented a tool to facilitate evaluation and comparison of different multiprocessor scheduling and synchronization approaches, as well as different partitioning heuristics. We have applied the tool in the evaluation of several partitioning heuristic algorithms, and the tool is flexible to which any new scheduling or synchronization protocol as well as any new partitioning heuristic can easily be added.</p>
|
492 |
Implementation and evaluation of a queuing discipline in LinuxFranked, Lennart, Håsäther, David January 2010 (has links)
<p>Streaming video and VoIP are two popular services used over the Internet, and as the number of users increases, the demand on the network routers also increases. Since both streaming video and VoIP have a variable traffic flow, the routers must always have some free space in their receive buffers to handle traffic bursts. If not, packet loss may occur that will result in a degraded quality of the services. In this project, a fuzzy logic based Active Queue Management (AQM) will be implemented, which might help reduce this problem. This algorithm has currently only been tested in a simulated environment. This algorithm will then be evaluated and compared to some of the existing AQMs. The results will also be compared to a stream that only uses a First-In, First-Out (FIFO) queue, which will work as a baseline. Since an AQM is not the only means used to reduce delay and jitter, different AQMs will also be combined with two different transport protocols, User Datagram Protocol (UDP) and the new Datagram Congestion Control Protocol (DCCP). The resulting implementation performed on a par with RED (Random Early Detection), one of the most common AQMs.</p>
|
493 |
Undersökning, implementering och utvärdering av ett system för att visualisera immaterialrättsdataPettersson, Erik January 2009 (has links)
<p>Detta arbete har utförts tillsammans med Ipendo Systems AB i Linköping. Företaget utvecklar ett system för att administrera immateriella rättigheter som heter Ipendo Platform. Kunder som använder Ipendo Platform saknar idag ett sätt att visualisera och analysera den data som de har inlagda i systemet. Syftet med detta examensarbete har varit att från grunden ta fram och realisera en modul till Ipendo Platform som visualiserar och analyserar kunders immaterialrättighetsdata. Vidare har syftet också varit att integrera modulen mot Europeiska patentverkets publika databas så att konkurrensanalyser kan göras mellan olika företag. Då Ipendo Platform används av många olika intressenter ställer det höga krav på användbarhet och kvalitet. Ett prototypbaserat och iterativt arbetssätt med en nära relation mot kunden har därför används under utvecklingen. Resultatet av examensarbetet är en fristående modul till Ipendo Platform som visualiserar och utför analyser av immateriella rättigheter. Utöver modulen har det valda arbetssättet jämförts med några vanliga systemutvecklingsmetoder för att se vilka av dem som bäst lämpar sig att använda för att arbeta prototypbaserat med höga krav på användbarhet.</p>
|
494 |
Mjukvaruprojekt och konsekvenserna av ScrumStenehall, Johan, Rahmani, Solmaz January 2009 (has links)
<p>Under sent 1990-tal började utvecklare att bli mer och mer missnöjda med rådande arbetsformer i projekt. Utvecklarna upplevde att modeller som vattenfallsmodellen inte längre speglade verkligheten för utvecklingen. Detta missnöje resulterade i att en mängd nya arbetsmodeller uppstod och 2001 samlades de under Agile Manifesto. Agile lägger tyngdpunkten på individfokus, fungerande mjukvara, kundsamarbete och föränderlighet. Scrum är just nu ett av de mest populära ramverken inom agile.Tieto har använt sig av agile och då främst Scrum i sina projekt sedan tidigt 2000-tal och haft lyckat resultat. Projekten som använt Scrum har levererat i tid och haft nöjda kunder. Dock har Tieto inte utrett vilka konsekvenser Scrum får för ett projekt. Denna studies fokus låg på att undersöka konsekvenserna av att använda Scrum i ett projekt. Detta gjordes med hjälp av intervjuer, observationer och en enkät där arbetet för ett antal Scrum-projekt studerades. Resultatet jämfördes sedan med rådande litteratur inom ämnet samt studier från The Standish group, VersionOne och Yahoo!.Rapportens slutsats är att Scrum påverkar mer än bara arbetssättet och att dessa effekter måste betänkas. Många positiva konsekvenser av användandet av Scrum kunde ses men även ett antal risker upptäcktes. För ett lyckat Scrum-projekt behövs en delaktig produktägare, en engagerad ScrumMaster och ett team som tycker om att ta eget ansvar.</p> / <p>During the late 1990s, developers became more and more dissatisfied with the current way of working in the projects. Developers felt that models such as the waterfall model did not reflect the reality of how software development works in practice. This dissatisfaction led to the development of new models and in 2001 they gathered under the same name in the Agile Manifesto. Agile focuses on working software, customer collaboration and variability. Scrum is currently one of the most popular frameworks in agile.Tieto has implemented agile and particularly Scrum in their projects since early 2000 and have had success. The projects that used Scrum delivered on time and had satisfied customers. However Tieto has not investigated the impact Scrum has on projects. This study focus was on examining the consequences of using Scrum in a project. This was done through interviews, observations and a survey in which the work of a number of Scrum projects were studied. The result was then compared with the current literature in the subject, and studies by The Standish Group, VersionOne and Yahoo!.The report concludes that Scrum affects more than just the way of working and that these effects must be taken under consideration. Many positive consequences of the use of Scrum could be seen but also a number of risks were detected. For a successful Scrum project one needs an involved product owner, a committed ScrumMaster and a team that likes to take responsibility.</p>
|
495 |
Utveckling av ögonstyrt kommunikationshjälpmedel för intensivvårdspatienter / Development of an <em>eyecontrolled</em> <em>communicationaid</em> for patients in <em>intensivecare units</em>Klasson, Sofia January 2010 (has links)
<p>Thousands of people all over the world suffer from injuries that temporary affects their ability to speak or inother ways communicate. A very common procedure for persons that suffer from some kind of breathingproblem in the higher parts of the neck is called tracheotomy. This prevents the patient from speaking whenno air passes the vocal cords. There have been many studies done to understand how these patientsexperience this period. The results are consistent, the patients often feel fear, frustration and worries aboutthe future.Tobii Technology develops a technique called eyetracking wich enables persons to control a computer with theeyes. In this thesis eyetracking products for persons with permanent communication disabilities are used todevelop a communication aid for people with temporary communication disabilities. This is accomplishedthrough interviews, user interface development techniques and finally an evaluation of the product using afocus groupThousands of people all over the world suffer from injuries that temporary affects their ability to speak or inother ways communicate. A very common procedure for persons that suffer from some kind of breathingproblem in the higher parts of the neck is called tracheotomy. This prevents the patient from speaking whenno air passes the vocal cords. There have been many studies done to understand how these patientsexperience this period. The results are consistent, the patients often feel fear, frustration and worries aboutthe future.Tobii Technology develops a technique called eyetracking wich enables persons to control a computer with theeyes. In this thesis eyetracking products for persons with permanent communication disabilities are used todevelop a communication aid for people with temporary communication disabilities. This is accomplishedthrough interviews, user interface development techniques and finally an evaluation of the product using afocus group</p>
|
496 |
A portal based system for indoor environsAbrahamsson, Lars January 2006 (has links)
<p>The purpose of this thesis is to document the development of the graphics part of an extremely pluggable game engine/lab environment for a course in advanced game programming. This thesis is one out of five, and concerns indoor, realtime computer 3D graphics. It covers state-of-the-art techniques such as GLSL - the OpenGL Shading Language - and more well known techniques such as portal based rendering.</p>
|
497 |
RTL implementation of Viterbi DecoderChen, Wei January 2006 (has links)
<p>A forward error correction technique known as convolutional coding with Viterbi decoding was explored in this final thesis. This Viterbi project is part of the baseband Error control project at electrical engineering department, Linköping University.</p><p>In this project, the basic Viterbi decoder behavior model was built and simulated. The convolutional encoder, puncturing, 3 bit soft decision, BPSK and AWGN channel were implemented in MATLAB code. The BER was tested to evaluate the decoding performance.</p><p>The main issue of this thesis is to implement the RTL level model of Viterbi decoder. With the testing results of behavior model, with minimizing the data path, register size and butterflies in the design, we try to achieve a low silicon cost design. The RTL Viterbi decoder model includes the Branch Metric block, the Add-Compare-Select block, the trace-back block, the decoding block and next state block. With all done, we further understand about the Viterbi decoding algorithm and the DSP implementation methods.</p>
|
498 |
Evaluation on how to use SystemVerilog as a design and assertion languageMagnusson, Andreas January 2006 (has links)
<p>SystemVerilog är det första design och verifieringsspråk som har standardiserats och dess syfte är att bemöta de krav som kommer med den komplexitet dagens chip har. SystemVerilog är en expansion till det hårdvarubeskrivande språket Verilog-2001 och det har en rad bra funktioner för både design och verifiering. För tillfället finns det dock ingen definition på vilka delar av språket som kan användas för konstruktion och verktygstillverkarna kan själva bestämma vad som kan användas för syntes. Detta medför att det finns skillnader vad beträffar vilka delar av språket som stöds. SystemVerilog har även en underklass som underlättar för skrivandet av avancerade assertions, SVA, som öppnar upp för möjligheten för en designer att funktionalitetsverifiera sin design på ett effektivt sätt. SVA bidrar till ökad observerbarhet i konstruktionen och möjliggör användandet av andra verifieringsmetoder som formell verifiering etc. Detta examensarbetes huvuduppgift är att ta reda på hur SystemVerilog kan användas som designspråk och att reda ut hur man kan använda SVA på befintlig VHDL-kod utan att modifiera koden. Andra avsikter med rapporten är att utvärdera mognadsgraden på de verktyg som används för design på avdelningen, med avseende på SystemVerilog, samt att se på skillnader ellan SystemVerilog jämfört med det renodlade verifieringsspråket ’e’. </p>
|
499 |
Efficient WiMAX Receiver Implementation on a Programmable Baseband ProcessorAxell, Christian, Brogsten, Mikael January 2006 (has links)
<p>WiMAX provides broadband wireless access and uses OFDM as the underlying modulation technique. In an OFDM based wireless communication system, the channel will distort the transmitted signal and the performance is seriously degraded by synchronization mismatches between the transmitter and receiver. Therefore such systems require extensive digital signal processing of the received signal for retrieval of the transmitted information.</p><p>In this master thesis, parts of an IEEE 802.16d (WiMAX) receiver have been implemented on a programmable baseband processor. The implemented parts constitute baseband algorithms which compensates for the effects from the channel and synchronization errors. The processor has a new innovative architecture with an instruction set optimized for baseband applications.</p><p>This report includes theory behind the baseband algorithms as well as a presentation of how they are implemented on the processor. An impartial evaluation of the processor performance with respect to the algorithms used in the reference model is also presented in the report.</p>
|
500 |
Development of the NoGAP CL Hardware Description Language and its CompilerBlumenthal, Carl January 2007 (has links)
<p>The need for a more general hardware description language aimed specifically at processors, and vague notions and visions of how that language would be realized, lead to this thesis. The aim was to use the visions and initial ideas to evolve and formalize a language and begin implementing the tools to use it. The language, called NoGAP Common Language, is designed to give the programmer freedom to implement almost any processor design without being encumbered by many of the tedious tasks normally present in the creation process. While evolving the language it was chosen to borrow syntaxes from C++ and verilog to make the code and concepts easy to understand. The main advantages of NoGAP Common Language compared to RTL languages are;</p><p>-the ability to define the data paths of instructions separate from each other and have them merged automatically along with assigned timings to form the pipeline.</p><p>-having control paths automatically routed by activating named clauses of code coupled to control signals.</p><p>-being able to specify a decoder, where the instructions and control structures are defined, that control signals are routed to.</p><p>The implemented compiler was created with C++, Bison, and Flex and utilizes an AST structure, a symbol table, and a connection graph. The AST is traversed by several functions to generate the connection graph where the instructions of the processor can be merged into a pipeline. The compiler is in the early stages of development and much is left to do and solve. It has become clear though that the concepts of NoGAP Common Language can be implemented and are not just visions.</p> / <p>Behovet av ett mer generellt hårdvarubeskrivande språk specialiseret för processorer och visioner om ett sådant gav upphov till detta examensarbete. Målet var att utveckla visionerna, formalisera dem till ett fungerande språk och börja implementera dess verktyg. Språket, som kallas NoGAP Common Language, är designat för att ge programmeraren friheten att implementera nästan vilken processordesign som helst utan att bli nedtyngd av många av de enformiga uppgifter som annars måste utföras. Under utvecklingsprocessen valdes det att låna många syntax från C++ och verilog för att göra språket lätt att förstå och känna igen för många. De största fördelarna med att utveckla i NoGAP Common Language jämfört</p><p>med vanliga RTL språk som verilog är; </p><p>-att kunna specificera datavägar för instruktioner separat från varandra och få dem automatiskt förenade med hjälp av tidsangivelser till en pipeline.</p><p>-att få kontrollvägar automatiskt dragna genom att aktivera namngivna klausuler med kod kopplade till kontrollsignaler. </p><p>-att kunna specifiera en avkodare som kontrollvägarna kan kopplas till där</p><p>kodning för instruktioner kan anges. </p><p>Kompilatorn som implementerats med C++, Bison och Flex använder sig av en AST struktur, en symboltabell och en signalvägsgraf. AST strukturen traverseras av flera funktioner som bygger upp signalvägsgrafen där processorns instruktioner förenas till en pipeline. Utvecklingen av kompilatorn är ännu bara i de första stadierna och mycket är kvar att göra och lösa. Det har dock blivit klart att det är möjligt att implementera koncepten i NoGAP Common Language och att de inte bara är lösa visioner. </p>
|
Page generated in 0.0397 seconds