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Thesis (M.S.)--University of Delaware, 2007. / Principal faculty advisor: Guang R. Gao, Dept. of Electrical and Computer Engineering. Includes bibliographical references.

The Discrete Cosine Transform is used in many image and video compression standards. Many methods have been developed for efficiently computing the Discrete Cosine Transform including flowgraph algorithms, distributed arithmetic and two-dimensional decompositions. A new architecture based on distributed arithmetic is presented for computing the Discrete Cosine Transform and it's inverse. The main objective of the design is to minimize the area of the VLSI implementation while maintaining the throughput necessary for video and image compression standards such as MPEG and JPEG. Several improvements have been made compared to previously published distributed arithmetic architectures. These include elimination of four lookup tables and implementation of the lookup tables using logic instead of ROM. A model of the proposed architecture was written in C. The model was used to verify the accuracy of the architecture and to do JPEG compression on a series of test images. Behavioral simulations were performed with a hardware model written in the Verilog hardware description language. These behavioral simulations verify that the hardware implementation matches the C model. The model was synthesized using the Synopsis synthesis tool. The gate count and clock rate of the design were estimated using the synthesis results. / Graduation date: 1997

A VLSI system for image compression based on two dimensional discrete cosine transform (2-D DCT) is designed and its performance is estimated. The focus is mainly on the reduction of power consumption and a reasonable speed. A 2-D DCT algorithm called row-column decomposition is chosen for the VLSI design of the system. Then a modified power saving architecture is proposed based on the property and purpose of image compression. Several methods, including the use of low power library cells and low voltage (Vdd=1.5v), are used to achieve the goal of power reduction. Techniques that reduces power, such as ordering of input signals and common term sharing, are applied to the design of the system. These techniques and methods span from algorithm, architecture, logic style and circuit. In addition to using standard cells, some custom cells are also created. The control, timing and synchronization circuitry is detailed in the design of the system. HSPICE simulation shows that the designed 2-D DCT system can operate at more than 20MHz for 8 by 8 image blocks using 1.2u CMOS technology. Based on the effective switched capacitances provided by library cell data sheets, power consumption performance is estimated. The system consumes about 17mW at the maximum speed and the specified supply voltage. Comparisons to other implementations show that the designed system exceeds in power performance. / Graduation date: 1996

R.M. Redheffer. / Includes bibliographical references. / Army Signal Corps Contract no. W-36-039 sc-32037.

Direct, construct by construct translation from one high level language to another often produces convoluted, unnatural, and unreadable results, particularly when the source and target languages support different models of programming. A more readable and natural translation can be obtained by augmenting the translator with a program transformation system.

This paper outlines a three-step plan for generating English text from any semantic representation by applying a set of syntactic transformations to a collection of kernel sentences. The paper focuses on describing a program which realizes the third step of this plan. Step One separates the given representation into groups and generates from each group a set of kernel sentences. Step Two must decide based upon both syntactic and thematic considerations, the set of transformations that should be performed upon each set of kernels. The output of the first two steps provides the "TASK" for Step Three. Each element of the TASK corresponds to the generation of one English sentence, and in turn may be defined as a triple consisting of: (a) a list of kernel phrase markers; (b) a list of transformations to be performed upon the list of kernels; (c) a "syntactic separator" to separate or connect generated sentences. Step Three takes as input the results of Step One and Step Two. The program which implements Step three "reads" the TASK, executes the transformations indicated there, combines the altered kernels of each set into a sentence, performs a pronomialization process, and finally produces the appropriate English word string. This approach subdivides a hard problem into three more manageable and relatively independent pieces. It uses linguistically motivated theories at Step Two and Step Three. As implemented so far, Step Three is small and highly efficient. The system is flexible; all the transformations can be applied in any order. The system is general; it can be adapted easily to many domains.

Thesis (Ph. D.)--University of Chicago, Dept. of the Geophysical Sciences, August 1999. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (March 1, 2007) Vita. Includes bibliographical references.

Thesis (Ph.D.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (March 1, 2007) Vita. Includes bibliographical references.