by Lui Bong Chun, Richard. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references. / Abstract / Acknowledgment / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background for the Project --- p.1 / Chapter 1.1.1 --- Interests in Blue-Green Laser --- p.1 / Chapter 1.1.2 --- Progress of Blue-Green Laser --- p.2 / Chapter 1.2 --- The Aim of the Project --- p.3 / Chapter 1.3 --- Overview the Remaining Parts of this Thesis --- p.4 / Chapter 1.4 --- References --- p.6 / Chapter Chapter 2 --- Sum Frequency Generation --- p.8 / Chapter 2.1 --- Introduction --- p.8 / Chapter 2.2 --- Sum Frequency Generation --- p.8 / Chapter 2.2.1 --- Theoretical Background for Sum Frequency Generation --- p.9 / Chapter 2.2.2 --- The Coupled Wave Equations for SFG --- p.13 / Chapter 2.2.3 --- Phase Matching Considerations --- p.16 / Chapter 2.3 --- References --- p.18 / Chapter Chapter 3 --- Cerenkov Radiation --- p.19 / Chapter 3.1 --- Introduction --- p.19 / Chapter 3.2 --- The Properties of Cerenkov Radiation by Using TM Mode --- p.21 / Chapter 3.2.1 --- Refractive Index Notation --- p.23 / Chapter 3.2.2 --- Fundamental Wave TM Guides Mode --- p.23 / Chapter 3.2.3 --- Second Harmonic TM Radiation Mode --- p.24 / Chapter 3.2.4 --- Efficiency of SHG --- p.25 / Chapter 3.3 --- Simplified Model Analysis of Cerenkov Radiation in TE Mode --- p.29 / Chapter 3.4 --- Simulation --- p.33 / Chapter 3.4.1 --- Modeling the LiNb03 --- p.33 / Chapter 3.4.2 --- Modeling an Asymmetric Slab Waveguide ´ؤPMMA doped with MNA on Fused Quartz --- p.37 / Chapter 3.4.3 --- Modeling a Symmetric Slab Waveguide ´ؤPMMA doped with MNA on Fused Quartz --- p.42 / Chapter 3.5 --- References --- p.47 / Chapter Chapter 4 --- Ellipsometry --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.2 --- General Principles --- p.49 / Chapter 4.3 --- Basic Operation --- p.50 / Chapter 4.4 --- The Optical Constants of the Bulk Materials --- p.51 / Chapter 4.5 --- Calculation the Refractive Index of the Substrates --- p.53 / Chapter 4.6 --- Ellipsometric Theory for the Thin Film --- p.57 / Chapter 4.7 --- Measurement the Refractive Index and the Thickness of the Thin Film --- p.59 / Chapter 4.7.1 --- Data --- p.62 / Chapter 4.7.2 --- Discussions --- p.73 / Chapter 4.8 --- Calculation the Refractive Index of the thin Film by Considering as a Bulk Material --- p.78 / Chapter 4.9 --- References --- p.80 / Chapter Chapter 5 --- Prism Coupling --- p.81 / Chapter 5.1 --- Introduction --- p.81 / Chapter 5.2 --- Coupling of a Plane Wave --- p.82 / Chapter 5.3 --- Numerical Approach for the Calculation of the Coupling Efficiency --- p.85 / Chapter 5.4 --- Experiment --- p.88 / Chapter 5.4.1 --- Experimental Setup --- p.88 / Chapter 5.4.2 --- Experimental Result and Discussions --- p.90 / Chapter 5.5 --- References --- p.92 / Chapter Chapter 6 --- Conclusion --- p.93 / Chapter Chapter 7 --- Future Plans --- p.96 / Chapter 7.1 --- Simplified Model of Corona Poling --- p.96 / Chapter 7.2 --- Advanced Models of Poling --- p.98 / Chapter 7.2.1 --- Slab Waveguide --- p.98 / Chapter 7.2.2 --- Channel Waveguide --- p.99 / Chapter 7.3 --- References --- p.100 / Chapter Appendix 1 --- Materials' Descriptions --- p.A-l / Chapter A.1.1 --- 2-Methyl-4-Nitoaniline --- p.A-1 / Chapter A.1.2 --- Poly ( Methyl Methacrylate ) --- p.A-3 / Chapter A.1.3 --- References --- p.A-4 / Chapter Appendix 2 --- Fabrication Procedures --- p.A-5 / Chapter A.2.1 --- Cleaning the Apparatus --- p.A-5 / Chapter A.2.2 --- Cleaning the Substrate --- p.A-5 / Chapter A.2.3 --- Thin film Fabrication --- p.A-5 / Chapter A.2.4 --- Thin Film Removal --- p.A-6 / Chapter A.2.5 --- References --- p.A-6 / Chapter Appendix 3 --- Alpha Step --- p.A-7 / Chapter A.3.1 --- Introduction --- p.A-7 / Chapter A.3.2 --- Experimental Setup --- p.A-8 / Chapter A.3.3 --- Experimental Results --- p.A-9 / Chapter A.3.3.1 --- Thin Film of PMMA without Dopant --- p.A-9 / Chapter A.3.3.2 --- Thin Film of PMMA doped with MNA --- p.A-19 / Chapter A.3.4 --- Discussions --- p.A-27 / Chapter A.3.5 --- References --- p.A-28 / Chapter Appendix 4 --- Scanning Electron Microscope --- p.A-29 / Chapter A.4.1 --- Scanning Electron Microscope --- p.A-29 / Chapter A.4.2 --- Reference --- p.A-30 / Chapter Appendix 5 --- Gaussian Beam & Coordinate System Transformation --- p.A-31 / Chapter A.5.1 --- Gaussian Beam in a Homogeneous Medium --- p.A-31 / Chapter A.5.2 --- Transformation of the Coordinate Systems --- p.A-32 / Chapter A.5.3 --- Reference --- p.A-32 / Chapter Appendix 6 --- Waist Size Measurement of Gaussian Beam --- p.A-33 / Chapter A.6.1 --- Waist Size Measurement of Gaussian Beam --- p.A-33 / Chapter A.6.2 --- References --- p.A-34 / Chapter Appendix 7 --- Quasi Phase Matching --- p.A-35 / Chapter A. 7.1 --- Introduction --- p.A-35 / Chapter A.7.2 --- Basic Concept of QPM --- p.A-36 / Chapter A.7.3 --- References --- p.A-38 / Chapter Appendix 8 --- Program Listing --- p.A-41 / Chapter A.8.1 --- Program Listing ( Chapter 3 ) --- p.A-41 / Chapter A.8.1.1 --- Program 3.1 (transcendental.m ) --- p.A-41 / Chapter A.8.1.2 --- Program 3.2 (linbo3.m) --- p.A-42 / Chapter A.8.2 --- Program Listing ( Chapter 4 ) --- p.A-45 / Chapter A.8.2.1 --- Program 4.1 ( ellipsometry.m ) --- p.A-45 / Chapter A.8.3 --- Program Listing ( Chapter 5 ) --- p.A-47 / Chapter A.8.3.1 --- Program 5.1 ( parameter.m ) --- p.A-47 / Chapter A.8.3.2 --- Program 5.2 ( coupling.m ) --- p.A-49 / Chapter A.8.3.3 --- Program 5.3 ( v_3_amp.m ) --- p.A-50 / Chapter A.8.3.4 --- Program 5.4 ( input_profile.m ) --- p.A-51

For thesis abstract select View Thesis Title, Contents and Abstract

D.Ing. (Electrical and Electronic ) / This thesis describes a neural network based system for the classification of handwritten digits as found on real-life mail pieces. The proposed neural network uses a modular architecture which lends itself to parallel implementation. This modular architecture is shown to produce adequate performance levels while significantly reducing the required training time. The aim of the system is not only to achieve a high recognition performance, but also to gain more insight into the functioning of the neural networks. This is achieved by using separate feature extraction and classification stages. The output of the feature extraction stage gives a good indication of the final performance level of the classifier, even before training. The need for an optimal feature set is expressed to elevate the performance levels even further.

by Chung-Wing Ng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 100-107). / Abstracts in English and Chinese. / Abstract --- p.ii / Acknowledgment --- p.vi / Table of Contents --- p.vii / List of Tables --- p.x / List of Figures --- p.xi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Image-based Video Description --- p.2 / Chapter 1.2 --- Video Summary --- p.5 / Chapter 1.3 --- Video Matching --- p.6 / Chapter 1.4 --- Contributions --- p.7 / Chapter 1.5 --- Outline of Thesis --- p.8 / Chapter Chapter 2 --- Literature Review --- p.10 / Chapter 2.1 --- Video Retrieval in Digital Video Libraries --- p.11 / Chapter 2.1.1 --- The VISION Project --- p.11 / Chapter 2.1.2 --- The INFORMEDIA Project --- p.12 / Chapter 2.1.3 --- Discussion --- p.13 / Chapter 2.2 --- Video Structuring --- p.14 / Chapter 2.2.1 --- Video Segmentation --- p.16 / Chapter 2.2.2 --- Color histogram Extraction --- p.17 / Chapter 2.2.3 --- Further Structuring --- p.18 / Chapter 2.3 --- XML Technologies --- p.19 / Chapter 2.3.1 --- XML Syntax --- p.20 / Chapter 2.3.2 --- "Document Type Definition, DTD" --- p.21 / Chapter 2.3.3 --- "Extensible Stylesheet Language, XSL" --- p.21 / Chapter 2.4 --- SMIL Technology --- p.22 / Chapter 2.4.1 --- SMIL Syntax --- p.23 / Chapter 2.4.2 --- Model of SMIL Applications --- p.23 / Chapter Chapter 3 --- Overview of ADVISE --- p.25 / Chapter 3.1 --- Objectives --- p.26 / Chapter 3.2 --- System Architecture --- p.26 / Chapter 3.2.1 --- Video Preprocessing Module --- p.26 / Chapter 3.2.2 --- Web-based Video Retrieval Module --- p.30 / Chapter 3.2.3 --- Video Streaming Server --- p.34 / Chapter 3.3 --- Summary --- p.35 / Chapter Chapter 4 --- Construction of Video Table-of-Contents (V-ToC) --- p.36 / Chapter 4.1 --- Video Structuring --- p.37 / Chapter 4.1.1 --- Terms and Definitions --- p.37 / Chapter 4.1.2 --- Regional Color Histograms --- p.39 / Chapter 4.1.3 --- Video Shot Boundaries Detection --- p.43 / Chapter 4.1.4 --- Video Groups Formation --- p.47 / Chapter 4.1.5 --- Video Scenes Formation --- p.50 / Chapter 4.2 --- Storage and Presentation --- p.53 / Chapter 4.2.1 --- Definition of XML Video Structure --- p.54 / Chapter 4.2.2 --- V-ToC Presentation Using XSL --- p.55 / Chapter 4.3 --- Evaluation of Video Structure --- p.58 / Chapter Chapter 5 --- Video Summarization --- p.62 / Chapter 5.1 --- Terms and Definitions --- p.64 / Chapter 5.2 --- Video Features Used for Summarization --- p.65 / Chapter 5.3 --- Video Summarization Algorithm --- p.67 / Chapter 5.3.1 --- Combining Extracted Video Segments --- p.68 / Chapter 5.3.2 --- Scoring the Extracted Video Segments --- p.69 / Chapter 5.3.3 --- Selecting Extracted Video Segments --- p.70 / Chapter 5.3.4 --- Refining the Selection Result --- p.71 / Chapter 5.4 --- Video Summary in SMIL --- p.74 / Chapter 5.5 --- Evaluations --- p.76 / Chapter 5.5.1 --- Experiment 1: Percentages of Features Extracted --- p.76 / Chapter 5.5.2 --- Experiment 2: Evaluation of the Refinement Process --- p.78 / Chapter Chapter 6 --- Video Matching Using V-ToC --- p.80 / Chapter 6.1 --- Terms and Definitions --- p.81 / Chapter 6.2 --- Video Features Used for Matching --- p.82 / Chapter 6.3 --- Non-ordered Tree Matching Algorithm --- p.83 / Chapter 6.4 --- Ordered Tree Matching Algorithms --- p.87 / Chapter 6.5 --- Evaluation of Video Matching --- p.91 / Chapter 6.5.1 --- Applying Non-ordered Tree Matching --- p.92 / Chapter 6.5.2 --- Applying Ordered Tree Matching --- p.94 / Chapter Chapter 7 --- Conclusion --- p.96 / Bibliography --- p.100

Rewritable photochrome-based 3D optical data storage requires photochromic molecules with high two-photon absorption (2PA) cross sections. Currently, the low value of two-photon absorption cross sections of existing photochromes makes them unsuitable for practical application in 3D data storage. Worldwide attempts to increase the cross section of photochromic molecules by altering the chemical structure have yielded poor results. In this work, two ways to increase the two-photon absorption cross sections of photochromes were investigated. In the first method, partial success demonstrated by extending the conjugation of a photochromic molecule, a high two-photon absorption cross section of the closed form isomer and high photoconversion to the closed form were realized. At the same time, a decrease in photoswitching quantum yield and low photoconversion to open form was observed. A discussion is provided to explain the results, suggesting that the proposed method of extending the conjugation may not solve the problem. For this reason a new method for effective two-photon absorption cross section enhancement of photochromes was proposed. As a proof of principle, a new two-photon absorbing dye with a hydrogen bonding moiety was synthesized and used for the formation of supramolecular structures with a photochromic compound. Theoretical reasoning and experimental demonstration of energy transfer from the dye to the photochrome under one and two-photon excitation confirmed the practical value of the method. The effects of a 2PA dye on the photochromic properties of a diarylethene were investigated using a model compound to simplify data analysis. Formation of supramolecular structures was revealed using ¹H NMR spectroscopic methods. The model compound, having the same hydrogen bonding moiety as 2PA dye, has been demonstrated to bind with photochrome molecules at very low concentrations. Photochromic properties of 2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide, including conversions at the photostationary state, extinction coefficients, photoisomerization reaction rates and quantum yields, were shown to be affected by hydrogen bonding with the model compound - 2,6-bis-(acetamido)pyridine. The extent of this change was determined and discussed, demonstrating a balanced supramolecular strategy to modulate photochemical and photophysical properties of this important class of photochromic material.

A new technique for optical pattern recognition with two-center recording of persistent holograms in doubly doped LiNbO₃3:Fe:Mn crystal is presented, by which the holograms are localized in separate slices along the recording medium. The localized recording method has the distinctive advantage of selective recording and erasure of the individual holograms without affecting the entire holographic recording medium. This capability enables dynamic content modification of the optical pattern recognition systems. Also, the diffraction efficiency of localized holograms is much larger than that of the normal volume multiplexed holograms. It is theoretically shown that the localized holographic correlator (LHC) outperforms the conventional volume holographic correlators in terms of crosstalk, shift invariance, and capacity. The LHC is experimentally demonstrated. Several persistent holograms are localized within separate slices as close as 33 μm apart along the crystal. The excessive diffraction efficiency of the localized holograms is employed to enhance the LHC robustness through multiplexing several holograms per pattern within individual slices of the recording medium. A holographic data storage system based on two-center holographic recording in a doubly doped LiNbO3:Fe:Mn crystal is developed with angular multiplexing capability. The associated imaging system has been optimized for the pixel matching of pixelated bit patterns generated by a spatial light modulator (SLM) through the recording medium onto a camera. The initial multiplexed holograms show promising contrast of dark and bright pixels. With the optimized imaging system of the developed holographic memory, the implementation of a dynamic read/write data storage system with localized recording is envisioned. The large diffraction efficiency of the localized holograms enables multilevel (M-ary) data coding to improve the storage density of the system.

ANP; FINEP; MCT; CAPES / Este trabalho objetiva otimizar a localização de um robô móvel para a inspeção dos tanques de armazenamento de GLP -- Gás Liquefeito de Petróleo -- e permitir a navegação autônoma deste robô por toda a superfície do tanque. A falta de marcos no interior dos tanques levou ao desenvolvimento de uma solução envolvendo detecção de pequenas estruturas com sensores LIDAR (Light Detection and Ranging - Detecção e Telemetria por Luz) aplicada aos cordões de solda, estes sim presentes no interior do tanque, que é apresentada na primeira parte do trabalho. Em seguida, aplicando uma técnica de fusão de dados, as diferentes fontes de odometria presentes no robô são combinadas, permitindo uma precisão mais elevada na inspeção de modo geral. Por fim, o mapeamento e navegação simultâneos do exterior da esfera é abordado, a fim de se adicionar uma camada suplementar ao mapa digital, indicando os locais onde existem falhas. Testes para validação de cada uma das técnicas foram efetuados e uma análise de desempenho é apresentada ao final do trabalho. / This work aims to optimize localization of a climbing inspection robot for spherical LPG -- Liquified Petroleum Gas -- tanks and allow autonomous navigation along the entire surface of these tanks. One solution envolving small structures detection using LIDAR sensors is applied to the weld beads that are present inside the tanks. This solution is developed on the first part of this work. Following, a data fusion technique is used to combine the diferent odometry sources on the robot, resulting in a better, higher precision on the inspection as a whole. Finnaly, simultaneous mapping and navigation on the exterior of the spherical tank was studied in order to add one extra layer to the digital map, pinpointing the places where failures and weld beams were found. Validation tests for each one of this techniques are carried out and a performance analysis is also documented herein.

ANP; FINEP; MCT; CAPES / Este trabalho objetiva otimizar a localização de um robô móvel para a inspeção dos tanques de armazenamento de GLP -- Gás Liquefeito de Petróleo -- e permitir a navegação autônoma deste robô por toda a superfície do tanque. A falta de marcos no interior dos tanques levou ao desenvolvimento de uma solução envolvendo detecção de pequenas estruturas com sensores LIDAR (Light Detection and Ranging - Detecção e Telemetria por Luz) aplicada aos cordões de solda, estes sim presentes no interior do tanque, que é apresentada na primeira parte do trabalho. Em seguida, aplicando uma técnica de fusão de dados, as diferentes fontes de odometria presentes no robô são combinadas, permitindo uma precisão mais elevada na inspeção de modo geral. Por fim, o mapeamento e navegação simultâneos do exterior da esfera é abordado, a fim de se adicionar uma camada suplementar ao mapa digital, indicando os locais onde existem falhas. Testes para validação de cada uma das técnicas foram efetuados e uma análise de desempenho é apresentada ao final do trabalho. / This work aims to optimize localization of a climbing inspection robot for spherical LPG -- Liquified Petroleum Gas -- tanks and allow autonomous navigation along the entire surface of these tanks. One solution envolving small structures detection using LIDAR sensors is applied to the weld beads that are present inside the tanks. This solution is developed on the first part of this work. Following, a data fusion technique is used to combine the diferent odometry sources on the robot, resulting in a better, higher precision on the inspection as a whole. Finnaly, simultaneous mapping and navigation on the exterior of the spherical tank was studied in order to add one extra layer to the digital map, pinpointing the places where failures and weld beams were found. Validation tests for each one of this techniques are carried out and a performance analysis is also documented herein.