Custom hardware accelerators are commonly used in simulation systems requiring high computational power. Such applications often have few data dependencies, allowing implementation using parallel datapaths. For such problems, optimization of the datapath of the circuits leads to significant improvements in overall performance. / The Computer Arithmetic Synthesis Technology (CAST) framework, developed in this work, allows one to quickly explore the design space in three dimensions: the number system, the operator architecture and the configuration of individual operators. It utilizes sophisticated arithmetic algorithms and reconfigurable architectures, captured in the object libraries. The final result is an optimized datapath satisfying user requirements, and the output can be controlled at different levels. / To demonstrate its ability, the CAST framework is used to implement a number of simulation systems including the datapath for the force computation pipeline of N-body simulation and Monte Carlo simulation for interest rate financial derivatives. A novel multiplier generator and an efficient random number generator are also presented as basic building blocks for simulation. Together, these tools provide an easy way to describe simulation system in a number system independent manner, and generate implementation to satisfy different performance, area and accuracy constraints. / Tsoi Kuen Hung. / "November 2007." / Adviser: Philip H. W. Leong. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4862. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 106-118). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Gallivan, Martha A.; Committee Member: Hess, Dennis; Committee Member: Lee, Jay H.; Committee Member: Li, Mo; Committee Member: Ludovice, Pete.

T helper (Th) cell activation and development is one of the most critical events in regulating the adaptive immune response. Understanding its regulation could be of great therapeutical value as many severe diseases are associated with failure in controlling T cell activation and development. However, the regulation of T cell activation appears to be one of the most complex set of cellular and molecular interactions known in the immune system. There is therefore an urgent need for tools to unravel this complexity, and to make use of the quantitative experimental data. To address this issue, mathematical and computational models, based on rigorous biophysical and kinetic data, were developed to study the specific role of some of the major costimulatory molecules involved in Th cell activation, and others developed to investigate proposed theories about mechanisms involved in Th cell differentiation. The simulations of costimulation reveal new implications for the function of the costimulatory molecules CD28 and CTLA-4, and their ligands B7-1 and B7-2, and show how binding affinity, stoichiometric properties, expression levels, and, in particular, competition effects, all profoundly influence complex formation at the immunological synapse. The results support the concept that B7-2 and B7-1 are the dominant ligands of CD28 and CTLA-4, respectively, and indicate that the inability of B7-2 to recruit CTLA-4 to the synapse cannot be, as has been previously proposed, due to the different binding properties of B7-1 and B7-2. Simulations of Th cell development reveal that both instructive and selective processes are likely to be involved in Th cell differentiation. In addition, further simulations indicate that Th2 cells are more likely to become dominant by inhibiting Th1 cells (negative selection), rather than selecting their own growth (positive selection). This thesis also includes an experimental work in which the immunomodulatory role of the bacterial signalling molecule N-3-(oxododecanoyl)-L-homoserine lactone (OdDHL) was analysed. This study strongly suggests that OdDHL suppresses Th cell activation and development, and that it is likely targeting the intracellular signalling events involved in the early stages of Th cell activation.