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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

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.
2

Visual attention using game theory

Ramström, Ola January 2004 (has links)
No description available.
3

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>
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)
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. 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. 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. 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. 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 Re=11 x 106. 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. 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>QC 20101015</p>
8

Sammanställning av riktlinjer för utformning och användbarhetstest av interaktiva webbsidor. En studie av användbarheten på Folksams webbplats / Guidelines for the design and usability testing of interactive web pages

Ekwall, Emelie January 2002 (has links)
<p>På Folksam utförs vid starten av detta examensarbete ingen samordnad användbarhetstest vid design av företagets webbplats och dess applikationer. Arbetet med att utforma egna testanvisningar för användbarhetstest har precis tagit sin början och en grupp av anställda som ska ta på sig detta arbete har just bildats. Testanvisningarna utformas utifrån information som inhämtats under kurser, seminarier samt de anställdas egna erfarenheter. </p><p>Syftet med det examensarbetet som denna rapport beskriver har varit att utforma en utvärderingsmodell som skall användas som mall vid användbarhetstest under utvecklingsarbete av Folksams webbplats. Den utvärderingsmodell som tagits fram under arbetet är en slags sammanställning av de riktlinjer som finns för utformning av interaktiva webbsidor som möter användarens krav på användbarhet. </p><p>Dessutom har det inom ramen för detta arbete utförts användbarhetstester utifrån den framtagna utvärderingsmodellen. Dessa test har bidragit till kvalitetssäkring av utvärderingsmodellen samt praktiska synpunkter på användbarheten på en utvald del av Folksams webbplats. </p><p>Resultatet av testerna har visat att alla de problemområden som framkom vid test kunde relateras med någon eller några av riktlinjerna i utvärderingsmodellen. Denna bedöms därför som tillräckligt omfattande och kan tas i bruk som mall vid användbarhetstest på Folksam i befintligt skick.</p>
9

OLED : Evaluation and clarification of the new Organic Light Emitting Display technology

Stark, Patrik, Westling, Daniel January 2002 (has links)
<p>Organic Light Emitting Displays (OLEDs) are a new type of thin emissive displays predicted to possess superior properties to existing techniques e.g. Liquid Crystal Display (LCD). The main advantages are low power consumption and a thin display structure. This report contains an explanation of the emissive OLED technology, its functionality and the physics of the organic layer structure in an OLED. The technology is described with respect to the two classes of organic materials used in displays, small molecules and conjugated polymers. </p><p>The information is derived from a study of literature and from different measurements performed on a full-colour OLED microdisplay, based on colour filters. The evaluation of the OLED revealed the main disadvantage of an unsatisfactory lifetime of approximately only one week. The results of the measurements and study are furthermore compared to the traditional LCD technology. </p><p>A conclusion with the advantages and drawbacks with the OLED technology summarises the report together with a short analysis of the future for OLEDs, partly achieved through a written enquiry sent to approximately 20 possible OLED manufactures.</p>
10

Verktyg för mätning av tjänstekvalitet på bredbandsnät / Tools for measurement of service quality in broadband net

Shahraki, Homan January 2002 (has links)
<p>Operators and Internet service providers invest in broadband to be able to deliver new services that require higher data transmission rate. A way to make this possible is to use ADSL, Asymmetric Digital Subscriber Line, as the access technology. To be able to handle this technology, the service providers should do a pre-qualification. Methods and tools are needed to analyze the local copper lines and decide if these qualify for ADSL with respect to service availability and possible bandwidth through the lines. This report brings up some methods for pre-qualification of ADSL, the important quality parameters and how to gather them from the available services today. Further is the usage of quality parameters discussed for future demands on pre-qualification methods and tools.</p>

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