Physical Sciences and Mathematics Commons^™

Opportunistic Random Media Access In Wlans, Chong Tang

Master's Theses

This thesis proposes a new medium access protocol for IEEE 802.11 wireless local area networks, which is called opp01tunistic medium access. The protocol changes the media access opportunities of nodes by adjusting the contention window dynamically according to the different bit rates. Thereby, the protocol can reduce collision and improve throughput significantly. The n·aditional IEEE 802.11 standards access channel with binary exponential back-off algorithm and all nodes choose the back-off interval from the same initial range. The new protocol in this thesis divides nodes as well as contention windows in proportion to data rate. It offers three methods to group …

Flexrender: A Distributed Rendering Architecture For Ray Tracing Huge Scenes On Commodity Hardware., Robert Edward Somers

Master's Theses

As the quest for more realistic computer graphics marches steadily on, the demand for rich and detailed imagery is greater than ever. However, the current "sweet spot" in terms of price, power consumption, and performance is in commodity hardware. If we desire to render scenes with tens or hundreds of millions of polygons as cheaply as possible, we need a way of doing so that maximizes the use of the commodity hardware we already have at our disposal.

Techniques such as normal mapping and level of detail have attempted to address the problem by reducing the amount of geometry in …

Cuda Web Api Remote Execution Of Cuda Kernels Using Web Services, Massimo J. Becker

Master's Theses

Massively parallel programming is an increasingly growing field with the recent introduction of general purpose GPU computing. Modern graphics processors from NVIDIA and AMD have massively parallel architectures that can be used for such applications as 3D rendering, financial analysis, physics simulations, and biomedical analysis. These massively parallel systems are exposed to programmers through in- terfaces such as NVIDIAs CUDA, OpenCL, and Microsofts C++ AMP. These frame- works expose functionality using primarily either C or C++. In order to use these massively parallel frameworks, programs being implemented must be run on machines equipped with massively parallel hardware. These requirements limit …

Gpu-Accelerated Point-Based Color Bleeding, Ryan Daniel Schmitt

Master's Theses

Traditional global illumination lighting techniques like Radiosity and Monte Carlo sampling are computationally expensive. This has prompted the development of the Point-Based Color Bleeding (PBCB) algorithm by Pixar in order to approximate complex indirect illumination while meeting the demands of movie production; namely, reduced memory usage, surface shading independent run time, and faster renders than the aforementioned lighting techniques.

The PBCB algorithm works by discretizing a scene’s directly illuminated geometry into a point cloud (surfel) representation. When computing the indirect illumination at a point, the surfels are rasterized onto cube faces surrounding that point, and the constituent pixels are combined …

Suffix Trees For Document Retrieval, Ryan Reck

Master's Theses

This thesis presents a look at the suitability of Suffix Trees for full text indexing and retrieval. Typically suffix trees are built on a character level, where the tree records which characters follow each other character. By building suffix trees for documents based on words instead of characters, the resulting tree effectively indexes every word or sequence of words that occur in any of the documents. Ukkonnen's algorithm is adapted to build word-level suffix trees. But the primary focus is on developing Algorithms for searching the suffix tree for exact and approximate, or fuzzy, matches to arbitrary query strings. A …

Teaching Introductory Programming Concepts: A Comparison Of Scratch And Arduino, Anne Beug

Master's Theses

Computing has become an integral part of modern America. The Bureau of Labor Statistics estimates that between 2008 and 2018, the United States will have 1.4 million job openings in computing fields [1]. Since the early 2000's (just after the "dot com bust"), the number of students enrolled in computing majors (Computer Science, Computer Engineering, etc.) dropped precipitously by over 50%, only starting to rise again in 2009 [2]. One way to rectify to this gap between demand and supply is to start training students in computational thinking during high school. While the Computer Science Advanced Placement AB test has …

Automatic Document Classification In Small Environments, Jonathan David Mcelroy

Master's Theses

Document classification is used to sort and label documents. This gives users quicker access to relevant data. Users that work with large inflow of documents spend time filing and categorizing them to allow for easier procurement. The Automatic Classification and Document Filing (ACDF) system proposed here is designed to allow users working with files or documents to rely on the system to classify and store them with little manual attention. By using a system built on Hidden Markov Models, the documents in a smaller desktop environment are categorized with better results than the traditional Naive Bayes implementation of classification.