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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Modular Tool Architecture for Worst-Case Execution Time Analysis

Ermedahl, Andreas January 2003 (has links)
<p>Estimations of the Worst-Case Execution Time (WCET) are required in providing guarantees for timing of programs used in computer controlled products and other real-time computer systems. To derive program WCET estimates, both the properties of the software and the hardware must be considered. The traditional method to obtain WCET estimates is to test the system and measure the execution time. This is labour-intensive and error-prone work, which unfortunately cannot guarantee that the worst case is actually found. Static WCET analyses, on the other hand, are capable of generating safe WCET estimates without actually running the program. Such analyses use models of program flow and hardware timing to generate WCET estimates. </p><p>This thesis includes several contributions to the state-of-the-art in static WCET analysis: </p><p>(1) A tool architecture for static WCET analysis, which divides the WCET analysis into several steps, each with well-defined interfaces. This allows independent replacement of the</p><p>modules implementing the different steps, which makes it easy to customize a WCET tool for particular target hardware and analysis needs. </p><p>(2) A representation for the possible executions of a program. Compared to previous approaches, our representation extends the type of program flow information possible to express and handle in WCET analysis.</p><p>(3) A calculation method which explicitly extracts a longest program execution path. The method is more efficient than previously presented path-based methods, with a computational complexity close to linear in the size of the program.</p><p>(4) A calculation method using integer linear programming or constraint programming techniques for calculating the WCET estimate. The method extends the power of such calculation methods to handle new types of flow and timing information.</p><p>(5) A calculation method that first uses flow information to divide the program into smaller parts, then calculates individual WCET estimates for these parts, and finally combines these into an overall program WCET. This novel approach avoids potential complexity problems, while still providing high precision WCET estimates.</p><p>We have additionally implemented a prototype WCET analysis tool based on the proposed architecture. This tool is used for extensive evaluation of the precision and performance of our proposed methods. The results indicate that it is possible to perform WCET analysis in a modular fashion, and that this analysis produces high quality WCET estimates.</p>
2

User Interfaces for Accessing Information in Digital Repositories

Hauglid, Jon Olav January 2005 (has links)
Technological advances have made more information available to a larger part of the population than ever before. At the same time, the ability to locate and retrieve relevant information has become much more central. Combined, these trends form the motivation for the work presented in this thesis. My research focus has been to study how user interfaces for accessing information in large repositories can be designed to provide assistance to users without impairing usability. To this end, existing solutions have been examined and key design challenges identified. Most important among these were supporting a wider variety of users and handling complex data models and large repositories. In order to study these challenges, a methodology of repeated design-implementation-evaluation was used. To focus the research, the implemented solutions have all been based on four fundamental design ideas as to how a simple, usable interface for large information repositories can be made. The first presented system, SESAM, was designed for textual metadata databases. It was later extended to handle images. The second system, Savanta, targeted temporal video annotation databases. Both systems integrated various user interface techniques to create a rich and powerful environment for search, retrieval, browsing, exploration and analysis, while not sacrificing ease of use. Several usability evaluations highlighted two main contributions. They demonstrated the power of an iterative interaction model which integrates several methods for accessing information. It was also showed that using dynamic analysis to derive high-level information about properties of a collection of information objects, is a powerful technique that makes it much easier to get an overview of and navigate in such collections.
3

Visual attention using game theory

Ramström, Ola January 2004 (has links)
No description available.
4

Visual attention using game theory

Ramström, Ola January 2004 (has links)
No description available.
5

Interaktiv vittneskonfrontation : Utvecklandet av ett Directorspel för Internet

Brorsson, Hannah, Jacobsson, Ingrid January 2002 (has links)
<p>This final-year project has been performed at Strix production Efterlyst. The task has been to make a page under their homepage, with a game application that’s supposed to be interesting and also have a strong connection to the TV- program. </p><p>In the first part of the report, the reader will learn about the preparing work that was done before the work with the final game began. It is in these two test versions all the technical problems were tested, to finally be used or thrown away. </p><p>When all this was done, a lot of effort was made to make an attractive design of the game. The different design alternatives that were made were sent to Strix, so that they could choose what they liked the most. </p><p>After the technical description and the design, comes a part that explains how each frame in the game is constructed. In this part you can also read about the programming that were made to make the game work as it’s supposed to. </p><p>In the end of this report you can follow the difficulties that came up during the project, and how they have been solved.</p>
6

Interaktiv vittneskonfrontation : Utvecklandet av ett Directorspel för Internet

Brorsson, Hannah, Jacobsson, Ingrid January 2002 (has links)
This final-year project has been performed at Strix production Efterlyst. The task has been to make a page under their homepage, with a game application that’s supposed to be interesting and also have a strong connection to the TV- program. In the first part of the report, the reader will learn about the preparing work that was done before the work with the final game began. It is in these two test versions all the technical problems were tested, to finally be used or thrown away. When all this was done, a lot of effort was made to make an attractive design of the game. The different design alternatives that were made were sent to Strix, so that they could choose what they liked the most. After the technical description and the design, comes a part that explains how each frame in the game is constructed. In this part you can also read about the programming that were made to make the game work as it’s supposed to. In the end of this report you can follow the difficulties that came up during the project, and how they have been solved.
7

Aspects of the recursive projection method applied to flow calculations

Möller, Joakim January 2005 (has links)
<p>In this thesis, we have investigated the Recursive Projection Method, RPM, as an accelerator for computations of both steady and unsteady flows, and as a stabilizer in a bifurcation analysis.</p><p>The criterion of basis extraction is discussed. It can be interpreted as a tolerance for the accuracy of the eigenspace spanned by the identified basis, alternatively it can be viewed as a criterion when the approximative Krylov sequence becomes numerically rank deficient.</p><p>Steady state calculations were performed on two different turbulent test-cases; a 2D supersonic nozzle flow with the Spalart-Allmaras 1-equation model and a 2D sub-sonic airfoil simulation using the κ - ε model. RPM accelerated the test-cases with a factor between 2 and 5.</p><p>In multi-scale problems, it is often of interest to model the macro-scale behavior, still retaining the essential features of the full systems. The ``coarse time stepper'' is a heuristic approach for circumventing the analytical derivation of models. The system studied here is a linear lattice of non-linear reaction sites coupled by diffusion. After reformulation of the time-evolution equation as a fixed-point scheme, RPM coupled with arc-length continuation is used to calculate the bifurcation diagrams of the effective (but analytically unavailable) equation.</p><p>Within the frame-work of dual time-stepping, a common approach in unsteady CFD-simulation, RPM is used to accelerate the convergence. Two test-cases were investigated; the von Karman vortex-street behind a cylinder at Re=100, and the periodic shock oscillation of a symmetric airfoil at M ∞ = 0.76 with a Reynolds number <i>Re</i>=11 x 10<sup>6.</sup></p><p>It was believed that once a basis had been identified, it could be retained for several steps. The simulations usually showed that the basis could only be retained for one step.</p><p>The need for updating the basis motivates the use of Krylov methods. The most common method is the (Block-) Arnoldi algorithm. As the iteration proceeds, Krylov methods become increasingly expensive and restart is required. Two different restart algorithm were tested. The first is that of Lehoucq and Maschhoff, which uses a shifted QR iteration, the second is a block extension of the single-vector Arnoldi method due to Stewart. A flexible hybrid algorithm is derived combining the best features of the two.</p>
8

Bitfelsannolikheter för linjära blockkoder / Bit-Error probabilities for linear block codes

Puaca, Daniel January 2003 (has links)
<p>Detta examensarbete har en distinkt avgränsning vilket innebär att enbart binära koder som kan beskrivas med en generator- och en kontrollmatris behandlas, det vill säga linjära block koder. För att se hur felsannolikheten varierar har två metoder använts, dels en fullständig undersökning vilket innebär att alla linjärkombinationer av en generatormatris undersöks, dels en slumpmässig vilken innebär att enbart ett antal slumpmässigt utvalda linjärkombinationer undersöks. Den sistnämnda metoden används enbart när det blir för tidsödande att genomföra en fullständig undersökning. Resultatet visar att alla avbildningar till en linjär kod inte är ekvivalenta med avseende på felsannolikheten för de olika bitpositionerna i meddelandeordet. Detta innebär att vissa linjärkombinationer av en generatormatris för en given kod beter sig bättre än den ursprungliga generatormatrisen som definierar koden. Vissa koder kan till och med fås att bete sig snarlikt en perfekt kod. Som referens till de undersökta koderna har jag använt mig av Hamming koden, ham(7,4), vilken är en perfekt kod.</p>
9

Goodwill Reklambyrå på Internet : två webbapplikationer / Goodwill Reklambyrå on the Internet : two webbapplikations

Flodkvist, Julia, Forsberg, Hanna January 2002 (has links)
<p>Detta examensarbete är gjort för Goodwill Reklambyrå i Norrköping. Uppgifterna var att skapa en hemsida och en företagsportal åt företaget. Med företagsportal menas en applikation upplagd på Internet där företagets anställda kan läsa, uppdatera, radera och skapa poster som är lagrade i databaser. I huvudsak har Flash använts för att skapa hemsidan och ASP (Active Server Pages) för att bygga upp företagsportalen. Resultatet blev en underhållande och informativ hemsida och en säker och användbar företagsportal. I denna rapport får läsaren en utförlig redogörelse för arbetet. </p> / <p>This degree project is made for Goodwill Reklambyrå in Norrköping. The task was to create a homepage and a business community for the company. By business community we mean an application on the Internet where the company staff are able to read, update, delete and create posts which are stored in databases. Mainly have Flash been used to create the homepage and ASP (Active Server Pages) to build the business community. The final result was an entertaining and informative homepage and a secure and useable business community. In this report the reader gets a detailed statement of our work.</p>
10

WCDMA User Equipment Output Power Calibration / Uteffektskalibrering för WCDMA-telefon

Folkeson, Tea January 2003 (has links)
<p>To save time in Flextronics high volume production, the time for test and calibration of mobile telephones need to be as short and accurate as possible. In the wideband code division multiple access (WCDMA) case, the output power calibration is the most critical calibration concerning accuracy. The aim with this thesis was to find a faster calibration method than the one that exists today and still retain accuracy. </p><p>The Third Generation Partnership Project (3GPP) outlines the requirements of the output power and they must be thoroughly considered when choosing calibration method. Measurement accuracy and the behavior of the transmitter chain parameters also must be considered. </p><p>The output power in the WCDMA phone studied is controlled by seven parameters. The parameters are characterized in this thesis, and are found to be too hardware dependent to be predicted or to be seen as predictions from each other. </p><p>Since no parameter predictions are possible it was stated that all parameters have to be measured, and a new way of measuring them in a faster way is proposed. The principle of the new measurement method is presented, and the implemented software is tested and evaluated. The new method mainly makes use of the spectrum analyzer zero span function. </p><p>The evaluation shows that the new method is faster than the original and retains accuracy. The measurement uncertainties even seem to diminish, which implicates decreased temperature dependence due to faster measurement time.</p>

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