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Power electronic converters are being increasingly used on isolated marine power systems, to provide variable speed control of electric motors. As the rating of these drive converters increases, the converter load becomes a significant part of the total system load. Traditional methods for calculating the performance characristics, which assume the presence of an infinite busbar on the system, are not appropriate for such systems. The intercoupling which exists between system components such as synchronous generators, converters, and the drive motor must be included in the calculation. In this thesis, a commercially available software simulator Saber, is used to model a complete electrical cycloconverter propulsion drive, of the type which may be used for future Royal Navy frigates. This model includes the synchronous generators, cycloconverters, and induction motor drives. The simulation is performed in the time domain, which ensures that the intercoupling present between system components is preserved. The simulation is not restricted to one converter configuration, and has been used to investigate the relative merits of a number of possible converter connections. This method can be used to study drive performance under unbalanced conditions as well as for normal balanced operation. There is no perceived limit to the size, or complexity, of the converter systems which can be studied using this method. The only cost would be increased computer run times.

A significant portion of a modern digital system can be regarded as a network of many thousands of combinational logic functions. In a Very Large Scale Integration (VLSI) implementation each combinational logic function is realized as a logic gate on a silicon wafer. To synchronize the passage of a signal through a network of logic gates synchronizing elements are used. These inhibit or permit the flow of a signal through the network under the control of a global control signal. A portion of a digital system comprising a network of logic gates connected without feedback is referred to as a combinational logic network. A portion of a digital system containing both combinational logic functions and synchronizing elements is referred to as a synchronous logic network. This thesis is concerned with the development of techniques and theory for the computer aided design of combinational and synchronous logic networks including techniques for: organizing a combinational logic function for a dynamic logic macrocell style of VLSI implementation; rearranging synchronous logic networks with the goal of improving the performance of a VLSI realization and synthesizing logic expression representations of designs from recursive equations in a correctness preserving way. In particular, the following methods for assisting with the design of logic systems are presented: 1. A method for factoring logic equations which allows constraints specific to a dynamic logic macrocell implementation to guide the search for the factored form. 2. A method for retiming multiple phase synchronous logic networks. 3. A method for reorganizing the distribution of logic in a synchronous logic network so that the delay encountered by a signal rippling through the combinational logic between any pair of synchronizing elements is reduced. Particular results obtained from implementations of the methods proposed demonstrate their usefulness for the computer aided design of logic systems.

This thesis presents the design and development of the AHF, and the application of CAD in switching converters. The presentation begins by a review of previous work in AHF with special emphasis on its design principles. This is followed by a discussion and implementation of the CAD tools---CASA a control system software package and real time computer simulation. The former implements a novel approach toward the control loop stability analysis of switching converters. Essentially it employs the Block Diagram Technique to describe the circuit configuration allowing Active Compensation Technique (ACT) to be carried out. Real time simulation allows the investigation of the AHF transient behaviour in response to step changes in line voltage and load. A fast algorithm has been introduced that results in a tremendous reduction in simulation time. These CAD approaches were used to assist in the design and evaluation of the performance of AHF design. The final part of the thesis describes the development of a 400 and 600W prototypes which were designed with high specification. The process of the design is outlined in detail and the prototypes were implemented to a 400W output SMPS and a 288W UPS. The 400W SMPS was tested with and without the AHF. Comparison of these test results is included.

The engineering design process may be seen as a series of interrelated operations that are driven by decisions: each operation is carried out as the consequence of an associated decision. Hence, an effective design process relies heavily upon effective decision-making. As a consequence, supporting decision-making may be a significant means for achieving design process improvements. This thesis concentrates on how to support selection-type decision-making in conceptual engineering design.

Computer-Aided Design systems offer considerable potential for improving design process efficiency. To reduce the 'ease of use' barrier hindering full realisation of this potential amongst general mechanical engineering industries, many commercial systems are adopting a Feature-Based Design (FBD) metaphor. Typically the user is allowed to define and manipulate the design model using interface elements that introduce and control parametric geometry clusters, with engineering meaning, representing specific product features (such as threaded holes, slots, pockets and bosses). Sculptured products, such as golf club heads, shoe lasts, crockery and sanitary ware, are poorly supported by current FBD systems and previous research, because their complex shapes cannot be accurately defined using the geometrically primitive feature sets implemented. Where sculptured surface regions are allowed for, the system interface, data model and functionality are little different from that already provided in many commercial surface modelling systems, and so offer very little improvement in ease of use, quality or efficiency. This thesis presents research to propose and develop an FBD methodology and system suitable for sculptured products.

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by Leng Jing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 74-79). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.iii / ACKNOWLEDGEMENTS --- p.v / TABLE OF CONTENTS --- p.vi / LIST OF FIGURES --- p.viii / Chapter CHAPTER ONE --- INTRODUCTION --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Project Background --- p.4 / Chapter 1.3 --- Organization of the Thesis --- p.7 / Chapter CHAPTER TWO --- LITERATURE SURVEY --- p.8 / Chapter 2.1 --- History of Shoe Last Making --- p.8 / Chapter 2.2 --- Review of the Shoe Last Design Approach --- p.11 / Chapter CHAPTER THREE --- CUSTOM SHOE LAST DESIGN SYSTEM --- p.15 / Chapter 3.1 --- System Overview --- p.15 / Chapter 3.2 --- The Scanned Data and Data Alignment --- p.17 / Chapter 3.3 --- The Computation of Distance Map --- p.21 / Chapter 3.4 --- The Modification of Distance Map --- p.24 / Chapter 3.5 --- The Deformation --- p.30 / Chapter CHAPTER FOUR --- INTERACTIVE LOCAL DEFORMATIONS --- p.35 / Chapter 4.1 --- Local Deformations --- p.37 / Chapter 4.2 --- Adaptive Deformation --- p.39 / Chapter CHAPTER FIVE --- SYSTEM IMPLEMENTATION --- p.43 / Chapter 5.1 --- Add in Application to SolidWorks® --- p.43 / Chapter 5.2 --- The Matlab® Implementation --- p.52 / Chapter CHAPTER SIX --- CONCLUSIONS AND DISCUSSIONS --- p.56 / Chapter 6.1 --- Summary and Conclusions --- p.56 / Chapter 6.2 --- Recommendations for Future Research --- p.57 / APPENDEX A --- p.59 / SHOE SIZE CONVERTER --- p.59 / APPENDEX B --- p.60 / SOURCE CODE OF SHOE LAST CUSTOMIZATION SYSTEM --- p.60 / BIBLIOGRAPHY --- p.74