Sound is a crucial part of our life. Well-designed acoustic behaviors can lead to significant improvement in both physical and virtual interactions. In computer graphics, most existing methods focused primarily on improving the accuracy. It remained underexplored on how to develop efficient acoustic simulation algorithms for interactive practical applications. The challenges arise from the dilemma between expensive accurate simulations and fast feedback demanded by intuitive user interaction: traditional physics-based acoustic simulations are computationally expensive; yet, for end users to benefit from the simulations, it is crucial to give prompt feedback during interactions. In this thesis, I investigate how to develop efficient acoustic simulations for real-world applications such as immersive media and digital fabrication. To address the above-mentioned challenges, I leverage precomputation and optimization to significantly improve the speed while preserving the accuracy of complex acoustic phenomena. This work discusses three efforts along this research direction: First, to ease sound designer's workflow, we developed a fast keypoint-based precomputation algorithm to enable interactive acoustic transfer values in virtual sound simulations. Second, for realistic audio editing in 360° videos, we proposed an inverse material optimization based on fast sound simulation and a hybrid ambisonic audio synthesis that exploits the directional isotropy in spatial audios. Third, we devised a modular approach to efficiently simulate and optimize fabrication-ready acoustic filters, achieving orders of magnitudes speedup while maintaining the simulation accuracy. Through this series of projects, I demonstrate a wide range of applications made possible by efficient acoustic simulations.

This thesis develops techniques to evaluate and to improve the performance of single-server service systems with time-varying arrivals. The performance measures considered are the time-varying expected length of the queue and the expected customer waiting time. Time varying arrival rates are considered because they often occur in service systems. For example, arrival rates often vary significantly over the hours of each day and over the days of each week. Stochastic textbook methods do not apply to models with time-varying arrival rates. Hence new techniques are needed to provide high quality of service when stationary steady-state analysis is not appropriate. In contrast to the extensive recent literature on many-server queues with time-varying arrival rates, we focus on single-server queues with time-varying arrival rates. Single-server queues arise in real applications where there is no flexibility in the number of service facilities (servers). Different analysis techniques are required for single-server queues, because the two kinds of models exhibit very different performance. Many-server models are more tractable because methods for highly tractable infinite-server models can be applied. In contrast, single-server models are more complicated because it takes a long time to respond to a build up of workload when there is only one server. The thesis is divided into two parts: simulation algorithms for performance evaluation and service-rate controls for performance stabilization. The first part of the thesis develops algorithms to efficiently simulate the single-server time-varying queue. For the generality considered, no explicit mathematical formulas are available for calculating performance measures, so simulation experiments are needed to calculate and evaluate system performance. Efficient algorithms for both standard simulation and rare-event simulation are developed. The second part of the thesis develops service-rate controls to stabilize performance in the time-varying single-server queue. The performance stabilization problem aims to minimize fluctuations in mean waiting times for customers coming at different times even though the arrival rate is time-varying. A new service rate control is developed, where the service rate at each time is a function of the arrival rate function. We show that a specific service rate control can be found to stabilize performance. In turn, that service rate control can be used to provide guidance for real applications on optimal changes in staffing, processing speed or machine power status over time. Both the simulation experiments to evaluate performance of alternative service-rate controls and the simulation search algorithm to find the best parameters for a damped time-lag service-rate control are based on efficient performance evaluation algorithms in the first part of the thesis. In Chapter Two, we present an efficient algorithm to simulate a general non-Poisson non-stationary point process. The general point process can be represented as a time transformation of a rate-one base process and by exploiting a table of the inverse cumulative arrival rate function outside of simulation, we can efficiently convert the simulated rate-one process into the simulated general point process. The simulation experiments can be conducted in linear time subject to small error bounds. Then we can apply this efficient algorithm to generate the arrival process, the service process and thus to calculate performance measures for the G_t/G_t/1 queues, which are single-server queues with time-varying arrival rates and service rates. Service models are constructed for this purpose where time-varying service rates are specified separately from the rate-one service requirement process, and service times are determined by equating service requirements with integrals of service rates over a time period equal to the service time. In Chapter Three, we develop rare-event simulation algorithms in periodic GI_t/GI/1 queues and further in GI_t/GI_t/1 queues to estimate probabilities of rare but important events as a sanity check of the system, for example, estimating the probability that the waiting time is very long. Importance sampling, specifically exponential tilting, is required to estimate rare-event probabilities because in standard simulation, the number of experiments may blow up to achieve a targeted relative error and for each experiment, it may take a very long time to determine that the rare event does not happen. To extend the rare-event simulation algorithm to periodic queues, we derive a convenient expression for the periodic steady-state virtual waiting time. We apply this expression to establish bounds between the periodic workload and the steady-state workload in stationary queues, so that we can prove that the exponential tilting algorithm with the same parameter efficient in stationary queues is efficient in the periodic setting as well, which has a bounded relative error. We apply this algorithm to compute the periodic steady-state distribution of reflected periodic Brownian motion with support of a heavy-traffic limit theorem and to calculate the periodic steady-state distribution and moments of the virtual waiting time. This algorithm's advantage in calculating these distributions and moments is that it can directly estimate them at a specific position of the cycle without simulating the whole queueing process until steady state is reached for the whole cycle. In Chapter Four, we conduct simulation experiments to validate performance of four service-rate controls: the rate-matching control, which is directly proportional to the arrival rate, two square-root controls related to the square root staffing formula and the square-root control based on the mean stationary waiting time. Simulations show that the rate-matching control stabilizes the queue length distribution but not the virtual waiting time. This is consistent with established theoretical results, which follow from the observation that with rate-matching control, the queueing process becomes a time transformation of the stationary queueing process with constant arrival rates and service rates. Simulation results also show that the two square-root controls analogous to the server staffing formula are not effective in stabilizing performance. On the other hand, the alternative square-root service rate control based on the mean stationary waiting time approximately stabilizes the virtual waiting time when the cycle is long so that the arrival rate changes slowly enough. In Chapter Five, since we are mostly interested in stabilizing waiting times in more common scenarios when the traffic intensity is not close to one or when the arrival rate does not change slowly, we develop a damped time-lag service-rate control that performs fairly well for this purpose. This control is a modification of the rate-matching control involving a time lag and a damping factor. To find the best parameters for this control, we search over reasonable intervals for the most time-stable performance measures, which are computed by the extended rare-event simulation algorithm in GI_t/GI_t/1 queue. We conduct simulation experiments to validate that this control is effective for stabilizing the expected steady-state virtual waiting time (and its distribution to a large extent). We also establish a heavy-traffic limit with periodicity in the fluid scale to provide theoretical support for this control. We also show that there is a time-varying Little's law in heavy-traffic, which implies that this control cannot stabilize the queue length and the waiting time at the same time.

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.

Continuous Double Auction (CDA) is an efficient market institution for real-world trading. Negotiation capabilities for software agents are a central concern. Specially, agents need to be able to prepare bids for and evaluate offers on behalf of the users they represent with the aim of obtaining the maximum benefit for their users. They do this according to some bidding strategies. However, in many cases, on one hand, determining which strategy to employ is a complex decision making task because of the inherent uncertainty and dynamics of the auction market; on the other hand, strategies in the literature do not adapt very well to the dynamic markets. To this end, this thesis is concerned with developing novel bidding strategies for CDAs and enhancing the performance of different strategies in CDAs with respect to adaptivity by designing some generally used tools. / In this thesis, we focus on two types of CDAs. One is the CDAs with a deadline of inactive interval. Another is the CDAs with a fixed deadline. Three kinds of adaptive behaviors are proposed to enhance the performance of the widely adopted strategies in CDAs in the literature. They are adaptive softness, adaptive judgment of price acceptability, and adaptive time strategies. First, in the CDAs with a deadline of inactive interval, we design novel adaptive strategies, named Adaptive Attitude strategies, based on eagerness. Eagerness indicates the current supply and demand relationship from the agent's own point of view. To compute the value of eagerness, fuzzy sets and fuzzy logic are used to cope with the significant degrees of uncertainty in CDA markets. We define two kinds of adaptive behaviors, adaptive softness and adaptive judgment of price acceptability. Both of them resemble human traders' behaviors to compromise and set thresholds on acceptable prices in the trading process of real life markets and can enhance the performance of various strategies. Secondly, in the CDAs with a fixed deadline, time strategies are researched by us. In this market, every agent is aware of the time. Therefore adaptive time strategies are introduced to guide the agent to arrange his behavior according to time, which can enhance the performance of different strategies. Both the novel strategies and the enhanced strategies have been demonstrated to be superior in a wide range of CDA circumstances. We show that eagerness is a, practical solution for this class of application. We believe that this work represents an important step towards adapting agents in auctions. / Through the work in this thesis, Adaptive Attitude (AA) strategies have been demonstrated to be superior in a wide range of CDA scenarios. Moreover, three kinds of adaptive behaviors have been shown to greatly enhance the performance of the widely adopted strategies in CDAs. / Ma Huiye. / "August 2006." / Adviser: Ho Fung Leung. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1731. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 151-162). / 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.

A model of simulation with mixed-integer programming was created to simulate ordering, production planning, and supplying activities with and without supply information sharing in a three-level capacitated supply chain consisting of multiple suppliers, one manufacturer and multiple retailers. The simulation results indicate that supply information sharing can significantly reduce total cost and enhance service level of the whole supply chain and its members. It can also lessen order variance of downstream members in the supply chain. In addition, the impacts of supply information sharing on the supply chain performance are heavily influenced by demand patterns, capacity tightness, forecast accuracy, product substitution, and the availability of raw materials. / Fierce business competition forces enterprises to pay more attention to the coordination with their suppliers and customers. Information sharing is a prerequisite for coordinated supply chain operations. A wide range of literature emphasizes the importance of information sharing to supply chain performance. According to the direction of information flow between supply chain members, information sharing can be classified into two categories: demand-side information sharing and supply-side information sharing. Previous literature already made a wide variety of insightful explorations into demand-side information sharing in supply chain, such as demand, forecasting, inventory, and order information sharing. However, research efforts have rarely been made into supply-side information sharing. Therefore, this dissertation explores the impacts of supply-side information sharing. / Keywords. Information Sharing; Supply Chain; Simulation. / This dissertation contributes to extending the content and scope of supply chain information sharing research. Managerially speaking, the findings of this dissertation provide important reference for supply chain managers to implement supply information sharing in order to improve decision-making process, reduce uncertainties, and increase visibility in supply chain operations. / Zhou Qiang. / "June 2006." / Adviser: Tien-sheng Lee. / Source: Dissertation Abstracts International, Volume: 68-02, Section: A, page: 0648. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 170-176). / 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.

by Chan Chung-Kei, Thomas. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 125-[129]). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Semiconductor Device Physics --- p.5 / Chapter 2.1 --- IC Design Methodology --- p.6 / Chapter 2.1.1 --- System Level --- p.7 / Chapter 2.1.2 --- Circuit Level --- p.7 / Chapter 2.1.3 --- Device Level --- p.8 / Chapter 2.1.4 --- Process Level --- p.8 / Chapter 2.2 --- Classification of Device Models --- p.8 / Chapter 2.2.1 --- Circuit Models --- p.9 / Chapter 2.2.2 --- Physical Models --- p.10 / Chapter 2.3 --- Classical Drift-Diffusion model --- p.13 / Chapter 2.3.1 --- Basic Governing Equations in Semiconductors --- p.13 / Chapter 2.3.2 --- Shockley-Read-Hall Recombination Statics --- p.15 / Chapter 2.3.3 --- Boundary Conditions --- p.18 / Chapter 2.4 --- pn Junction at equilibrium --- p.20 / Chapter 2.4.1 --- The depletion approximation --- p.23 / Chapter 2.4.2 --- Current-voltage Characteristics --- p.26 / Chapter 3 --- Iteration Scheme --- p.30 / Chapter 3.1 --- Gummel's iteration scheme --- p.31 / Chapter 3.2 --- Modified Gummel's iteration scheme --- p.35 / Chapter 3.3 --- Solution of Differential Equation --- p.38 / Chapter 3.3.1 --- Finite Difference Method --- p.38 / Chapter 3.3.2 --- Moment Method --- p.39 / Chapter 4 --- Theory of Wavelets --- p.43 / Chapter 4.1 --- Multi-resolution Analysis --- p.43 / Chapter 4.1.1 --- Example of MRA with Haar Wavelet --- p.46 / Chapter 4.2 --- Orthonormal basis of Wavelets --- p.52 / Chapter 4.3 --- Fast Wavelet Transform --- p.56 / Chapter 4.4 --- Wavelets on the interval --- p.62 / Chapter 5 --- Galerkin-Wavelet Method --- p.66 / Chapter 5.1 --- Wavelet-based Moment Methods --- p.67 / Chapter 5.1.1 --- Wavelet transform on the stiffness matrix --- p.67 / Chapter 5.1.2 --- Wavelets as basis functions --- p.68 / Chapter 5.2 --- Galerkin-Wavelet method --- p.69 / Chapter 5.2.1 --- Boundary Conditions --- p.73 / Chapter 5.2.2 --- Adaptive Scheme --- p.74 / Chapter 5.2.3 --- The Choice of Classes of Wavelet Bases --- p.76 / Chapter 6 --- Numerical Results --- p.80 / Chapter 6.1 --- Steady State Solution --- p.81 / Chapter 6.1.1 --- Daubechies Wavelet N = 2 --- p.82 / Chapter 6.1.2 --- Daubechies Wavelet N=5 --- p.84 / Chapter 6.1.3 --- Discussion on Daubechies wavelets N = 2 and N=5 --- p.86 / Chapter 6.2 --- Transient Solution --- p.91 / Chapter 6.3 --- Convergence --- p.99 / Chapter 7 --- Conclusion --- p.103 / Chapter A --- Derivation for steady state --- p.107 / Chapter A.1 --- Generalized Moll-Ross Relation --- p.107 / Chapter A.2 --- Linearization of PDEs --- p.110 / Chapter B --- Derivation for transient state --- p.113 / Chapter C --- Notation --- p.119 / Chapter D --- Elements in the Stiffness Matrix --- p.122 / Bibliography --- p.125

No description available.

Sui, Xin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (p. 91-97). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- MAS-Based Resource Allocation Problems --- p.1 / Chapter 1.2 --- Combinatorial Auction As a Solution --- p.4 / Chapter 1.3 --- Strategy Issues --- p.5 / Chapter 1.4 --- Structure of This Work --- p.7 / Chapter 2 --- Combinatorial Auctions and Bidding Strategies --- p.9 / Chapter 2.1 --- Combinatorial Auctions for Resource Allocation --- p.9 / Chapter 2.2 --- Bidding Strategies in Combinatorial Auctions --- p.11 / Chapter 2.2.1 --- Berhault's Strategies --- p.11 / Chapter 2.2.2 --- An's Strategies --- p.13 / Chapter 2.2.3 --- Schwind´ةs Strategies --- p.15 / Chapter 2.2.4 --- Wilenius´ةs Strategy --- p.17 / Chapter 2.2.5 --- Overview of Previous Strategies --- p.18 / Chapter 3 --- An Adaptive Bidding Strategy in Static Markets --- p.21 / Chapter 3.1 --- Basic Concepts --- p.22 / Chapter 3.2 --- The Core Algorithm --- p.24 / Chapter 3.3 --- Experimental Evaluation --- p.31 / Chapter 3.3.1 --- Experiment Setup --- p.32 / Chapter 3.3.2 --- Experiment Results and Analysis --- p.33 / Chapter 4 --- An Adaptive Bidding Strategy in Dynamic Markets --- p.38 / Chapter 4.1 --- Basic Concepts --- p.39 / Chapter 4.2 --- The Core Algorithm --- p.42 / Chapter 4.3 --- Experimental Evaluation --- p.48 / Chapter 4.3.1 --- Experiment Setup --- p.49 / Chapter 4.3.2 --- Experiment Results and Analysis --- p.51 / Chapter 5 --- A Q-Learning Based Adaptive Bidding Strategy in Static Mar-kets --- p.59 / Chapter 5.1 --- An Overview of Q-Learning --- p.60 / Chapter 5.2 --- Basic Concepts --- p.63 / Chapter 5.3 --- The Core Algorithm --- p.65 / Chapter 5.4 --- Experimental Evaluation --- p.70 / Chapter 5.4.1 --- Experiment Setup --- p.70 / Chapter 5.4.2 --- Experiment Results and Analysis --- p.72 / Chapter 6 --- Discussion --- p.82 / Chapter 6.1 --- Applicability of the Adaptive Strategies --- p.82 / Chapter 6.2 --- Generalization of the Adaptive Strategies --- p.83 / Chapter 7 --- Conclusion and Future Work --- p.86 / Chapter 7.1 --- Conclusion --- p.86 / Chapter 7.2 --- Future Work --- p.88 / Bibliography --- p.91

Long, Qiaoxi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Abstracts in English and Chinese. / Abstract --- p.2 / 摘要 --- p.3 / Table of Contents --- p.4 / Acknowledgements --- p.6 / List of Figures --- p.7 / List of Tables --- p.9 / Chapter Chapter 1 --- Introduction --- p.10 / Chapter 1.1 --- Robot Soccer --- p.10 / Chapter 1.2 --- IRIP and IRIS --- p.11 / Chapter 1.3 --- Motivation and Literature Review --- p.14 / Chapter 1.4 --- Technical issues and Contributions --- p.15 / Chapter 1.5 --- Thesis Outline --- p.16 / Chapter Chapter 2 --- The IRIS system --- p.17 / Chapter 2.1 --- Hardware setup --- p.17 / Chapter 2.2 --- Software architecture --- p.21 / Chapter Chapter 3 --- Internet Accessibility --- p.26 / Chapter Chapter 4 --- Auto-charging --- p.32 / Chapter 4.1 --- Hardware setup --- p.33 / Chapter 4.2 --- Communication --- p.36 / Chapter 4.3 --- Vision --- p.41 / Chapter 4.4 --- Motion control --- p.44 / Chapter 4.4.1 --- APF --- p.44 / Chapter 4.4.2 --- CRC --- p.50 / Chapter 4.5 --- Processing Schemes --- p.51 / Chapter Chapter 5 --- Auto-Scoring and Auto-Judging --- p.56 / Chapter 5.1 --- Auto-scoring --- p.56 / Chapter 5.2 --- Auto-judging --- p.57 / Chapter 5.3 --- Judge robot --- p.59 / Chapter Chapter 6 --- Experimental Results --- p.63 / Chapter Chapter 7 --- Conclusions --- p.69 / Chapter 7.1 --- Summary --- p.69 / Chapter 7.2 --- Future work --- p.70 / Appendix A --- p.72 / Bibliography --- p.73

It is generally accepted that biological membranes consist of a lipid bilayer matrix with proteins incorporated into the lipid bilayer. Typically, these membranes are negatively charged due to the presence of negatively charged lipids in the bilayer as well as negatively charged molecular groups on proteins. Biologically active molecules, such as environmental pollutants, enter the membrane from the aqueous phase by adsorption or partitioning into the lipid bilayer. The thesis consists of two parts. Part I is a computational study of spatial distribution of electric potential in the aqueous portion of the membrane-water interface using two models of charge distribution: (i) the discrete charge model, in which charges are located on a square lattice either on the surface or embedded in the membrane: (ii) the continuous charge density (smeared charge), Gouy-Chapman, model in which the charge is assumed to be evenly spread on the membrane surface. The computed distributions of electric potential are used to predict spatial distributions of positively charged hexavalent cation of Ruthenium Red (RuR) at the membranewater interface. It was found that anomalous behavior of RuR cannot be explained by this version of the discrete charge theory. Part II is concerned with the distribution of ionized and un-ionized species of 2,4,6-Trichlorophenol (2,4,6-TrCP) in octanol-water system, which is often used as an experimental model for predicting the distribution of toxic chemicals in the environment. In this experimental study we obtained the pH dependence of the total distribution coefficient of 2,4,6-TrCP from which the octanol water partition coefficients of the un-ionized and ionized species were determined. We compared the octanol-water partition coefficient of several chlorophenols with experimental data on adsorption of ionized chlorophenols to lipid membranes. It was found that the membrane-water partition coefficient of ionized 2,4,6-TrCP is about 240 greater than that predicted from the octanol-water system. This finding supports the hypothesis that octanol-water partition coefficients cannot be used for predicting concentrations of ionized species of chlorophenols in lipid membranes.