Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 48-51). Also available on the World Wide Web.

The paradigm of separate source-channel coding is inspired by Shannon's separation result, which implies the asymptotic optimality of designing source and channel coding independently from each other. The result exploits the fact that channel error probabilities can be made arbitrarily small, as long as the block length of the channel code can be made arbitrarily large. However, this is not possible in practice, where the block length is either fixed or restricted to a range of finite values. As a result, the optimality of source and channel coding separation becomes unknown, leading researchers to consider joint source-channel coding (JSCC) to further improve the performance of practical systems that must operate in the finite block length regime. With this motivation, this thesis investigates the application of JSCC principles for multimedia communications over point-to-point, broadcast, and relay channels. All analyses are conducted from the perspective of end-to-end distortion (EED) for results that are applicable to channel codes with finite block lengths in pursuing insights into practical design. The thesis first revisits the fundamental open problem of the separation of source and channel coding in the finite block length regime. Derived formulations and numerical analyses for a source-channel coding system reveal many scenarios where the EED reduction is positive when pairing the channel-optimized source quantizer (COSQ) with an optimal channel code, hence establishing the invalidity of the separation theorem in the finite block length regime. With this, further improvements to JSCC systems are considered by augmenting error detection codes with the COSQ. Closed-form EED expressions for such system are derived, from which necessary optimality conditions are identified and used in proposed algorithms for system design. Results for both the point-to-point and broadcast channels demonstrate significant reductions to the EED without sacrificing bandwidth when considering a tradeoff between quantization and error detection coding rates. Lastly, the JSCC system is considered under relay channels, for which a computable measure of the EED is derived for any relay channel conditions with nonzero channel error probabilities. To emphasize the importance of analyzing JSCC systems under finite block lengths, the large sub-optimality in performance is demonstrated when solving the power allocation configuration problem according to capacity-based formulations that disregard channel errors, as opposed to those based on the EED. Although this thesis only considers one JSCC setup of many, it is concluded that consideration of JSCC systems from a non-asymptotic perspective not only is more meaningful, but also reveals more relevant insight into practical system design. This thesis accomplishes such by maintaining the EED as a measure of system performance in each of the considered point-to-point, broadcast, and relay cases.

Marine ecosystem-based management requires end to end models, which are models capable of representing the entire ecosystem including physical, chemical and biological processes, anthropogenic activities, and multiple species with different sizes, life histories and from different trophic levels. To adequately represent ecosystem dynamics in shallow coastal regions, end-to-end models may need to include macrobiota species (wild and aquacultured) and may have to allow feedbacks (i.e. two-way coupling) between macrobiota and planktonic ecosystem dynamics. This is because the biomass of macrobiota can locally exceed the biomass of plankton, thus influencing the distribution of planktonic ecosystem tracers and altering the overall food web structure. Here, I describe a hybrid (Eulerian/Individual-Based) ecosystem framework, implemented in the Regional Ocean Modeling System (ROMS), a state-of-the-art 3-D ocean circulation model. The framework was applied to a model of a synthetic embayment containing seagrass, rockweed and kelp beds, a wild oyster reef, a mussel ranch and a fish farm. I found that two-way coupling is essential to reproduce expected spatial patterns of all variables and to conserve mass in the system. I also developed a shellfish ecophysiology model (SHELL E) and compared its results against water samples collected over 5 years in Ship Harbour, a fjord with mussel aquaculture in Nova Scotia, Eastern Canada. Also, from a high-resolution bio-optical survey of the fjord, I found that mussels decrease phytoplankton biomass inside the farm, but also cause a bloom of phytoplankton outside the farm. Using ROMS/SHELL-E, I determined that the increase of phytoplankton around the farm is caused by the waste products of the farmed bivalves, which have a fertilization effect, enhancing phytoplankton production outside the farm during nutrient-limited and light-replete conditions (i.e. late spring to late fall in Ship Harbour). The main conclusion of this thesis is that—in shallow coastal regions—ecosystem models must represent bilateral interactions between macrobiota and physical-planktonic dynamics, in a spatially-explicit setting, to adequately represent mass flows and ecosystem dynamics. The hybrid end-to-end modelling system provides a computationally efficient framework for describing these interactions and, through careful comparisons against observations, can be a powerful tool to test hypotheses and generate insights into coastal ecosystems.

A precise simulation requires a large amount of input data such as geometrical descriptions of the crystal structure, the external forces and loads, and quantitative properties of the material. Although some powerful applications already exist for research purposes, they are not widely used in education due to complex structure and unintuitive operation. To cater to the generic user base, a front-end application for material simulation software is introduced. With a graphic interface, it provides a more efficient way to conduct the simulation and to educate students who want to enlarge knowledge in relevant fields. We first discuss how we explore the solution for the front-end application and how to develop it on top of the material simulation software developed by mechanical engineering lab from Georgia Tech Lorraine. The user interface design, the functionality and the whole user experience are primary factors determining the product success or failure. This material simulation software helps researchers resolve the motion and the interactions of a large ensemble of dislocations for single or multi-layered 3D materials. However, the algorithm it utilizes is not well optimized and parallelized, so its performance of speedup cannot scale when using more CPUs in the cluster. This problem leads to the second topic on scientific computing, so in this thesis we offer different approaches that attempt to improve the parallelization and optimize the scalability.

This thesis presents the design, implementation and fabrication for a 0.13μm interface to a capacitive MEMS accelerometer. By varying the number of amplifier slices used in concurrence based on different full scale input ranges, the analog circuitry power scales as the input range scales. Due to the oversampling nature of typical accelerometer front ends, for a full-scale input increase of N times, the analog circuitry power reduces by N2 times. The front end has two signal amplification stages, with the first stage power scaled. The chip is 1.15mmx1.15mm and implemented in a 0.13μm CMOS process. The design was packaged with the MEMS accelerometer chip inside a 44 pin CQFP. Measured results show an output rms noise of 63μVrms in a 100Hz bandwidth. The total analog circuitry power scales very linearly with different full scale ranges. A novel simple offset removal network is also shown and confirmed via measurement results.

This thesis presents the design, implementation and fabrication for a 0.13μm interface to a capacitive MEMS accelerometer. By varying the number of amplifier slices used in concurrence based on different full scale input ranges, the analog circuitry power scales as the input range scales. Due to the oversampling nature of typical accelerometer front ends, for a full-scale input increase of N times, the analog circuitry power reduces by N2 times. The front end has two signal amplification stages, with the first stage power scaled. The chip is 1.15mmx1.15mm and implemented in a 0.13μm CMOS process. The design was packaged with the MEMS accelerometer chip inside a 44 pin CQFP. Measured results show an output rms noise of 63μVrms in a 100Hz bandwidth. The total analog circuitry power scales very linearly with different full scale ranges. A novel simple offset removal network is also shown and confirmed via measurement results.

Thesis (M.A.)--Bowling Green State University, 2008. / Document formatted into pages; contains v, 96 p. Includes bibliographical references.

Thesis (M.P.A.)--University of Hong Kong, 1993.

Thesis (M.P.A.)--University of Hong Kong, 1993. / Also available in print.

Orientador: Carlos Alberto Soufen / Banca: Carlos Elias da Silva Junior / Banca: Momotaro Imaizumi / Resumo: O aço austenítico manganês, contendo cerca de 1,2%C e 12%Mn, é único na medida em que combina alta tenacidade e ductilidade com alta capacidade de endurecimento em trabalho, normalmente, boa resistência ao desgate. Consequentemente, este metal apresenta uma aceitação muito útil como material de engenharia, sendo amplamente utilizado, com pequenas modificações na composição e tratamento térmico, principalmente nas áreas de terraplanagem, minas e pedreiras, bem como perfuração de petróleo siderurgia, dragagem, a exploração florestal, e na fabricação de cimento e produtos de argila. Também são utilizados em equipamentos de manuseio e processamento térreo de materiais (tais como britadores, moinhos de trituração, dragadores, escavadoras baldes e dentes, e bombas para a movimentação de cascalho e rochas). Neste trabalho estudou-se a influência de composição química no encruamento e resistência ao desgaste do aço Hadfield. Foram analisadas quatro composições químicas diferentes desse material, que inicialmente foi submetido ao tratamento térmico de solubilização na temperatura de 1080ºC(1976ºC) com posterior resfriamento em água. Em seguida o material foi submetido ao processo de aplainamento no retirada de 1 mm de material. Dessas amostras, foram retirados corpos de prova para a análise metalográfica, que foram preparadas através do lixamento, polimento e ataque químico, e também o material para análise de desgaste, cujos corpos de prova foram preparados em formato cilíndrico com diâmetro e altura de dez milímetros. A análise metalográfica revelou menor profundidade de encruamento no material cuja composição apresenta titânio e alta porcentagem de cromo. Essa mesma composição, apresentou maior resistência ao desgaste / Abstract: The austenitic manganese steel, containing about 1,2%C and 12%Mn, is the only one which combines high tenacity and ductility with high tenacity and ductility with high capacity of hardening during the work, and usually, it has good resistance to wear As a result, this metal shows a very useful acceptance as a engineering material, being widely used with just small changes in the composition and termal treatment mainly in the lands of earthwork , mines and quarries, besides drilling of petroleum, steel mill, dredging, forestry exploration and in the manufacturing of cement and in the manufacturing of cement and clay products. They are also used in the equipments to handle ans work with land floor materials (like crushers, mill crushers, dredges, tooth and bucket excavators and pumps to move gravel and rocks). In this work it was studied the influence of the chemical composition on the hardening and resistance to wear of hadfield steel. Four different chemical compositions of this material were analyzed, at first it was subdued to a thermal treatment of folubilization in the temperature of 1080ºC (1976ºF) being chilled with water. After the material was subdued to the plaining process it was withdrawn 1mm. From this samples were withdrawn some parts to a metalography analysis and they were prepared to be sanded, polished and to a chemical attack ans the material that will be analyzed the wear, whose parts were prepared in a cylindrical shape with diameter and height of tem millimetres. The metalography analysis revealed a smaller deep in the hardening of the material whose composition has titanium and high percentage of chrome. In the same composition it was noticed a bigger resistance to wear / Mestre