Yongsheung Ou. / "March 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 119-130). / 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 Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Kar Ki Chan. / "November 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (p. 104-113). / 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 Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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Orientador: Roberto André Kraenkel / Banca: André M. de Roos / Banca: Marcus A.M. de Aguiar / Resumo: Predação intraguilda é um tipo de interação muito comum entre as espécies e pode influenciar fortemente na composição das comunidades ecológicas. Ela ocorre quando dois consumidores que compartilham de um mesmo recurso, e portanto competem, também apresentam comportamento predatório entre si. O consumidor que preda o seu competidor é frequentemente chamado de predador intraguilda, enquanto aquele que é predado é conhecido como presa intraguilda. Nesse trabalho nós investigamos alguns aspectos teóricos sobre esse tipo de interação. Primeiramente analisamos um experimento com ácaros predadores que foi realizado para testas as predições da teoria sobre padrões de exclusão em um gradiente de produtividade. Embora esse experimento foi cuidadosamente projetado para testar afirmações da teoria, seus resultados não concordam com ela. Utilizando um modelo bem simples para predação intraguilda que serve como uma representação daquele sistema, nós mostramos que: se levarmos em conta a dinâmica durante os transientes, e não apenas os resultados no equilíbrio, em que a teoria usual se baseia, e considerarmos que quando uma população atinge níveis muito baixos corresponde a uma extinção na realidade, os resultados experimentais concordam com a teoria. Em seguida nós estudamos questões que dizem respeito a influência dos diferentes estágios de vida dos indivíduos para a dinâmica da predação intraguilda. Nós introduzimos um modelo com estrutura de estágio em ambos os consumidores e consideramos a predação ocorrendo apenas dos adultos do predador intraguilda sobre os juvenis da presa intraguilda. Tem-se acreditado que essa interação dependente de estágio pode ter grandes efeitos sobre a dinâmica, uma vez que a pressão predatória sobre a presa intraguilda é reduzida... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Intraguild predation is a widespread interaction between species and can strongly influence communities composition. It occurs when two consumers which share a common resource, and hence compete, also engage into predation. The consumer which can prey on its competitor is often referred to as the intraguild predator while the other is called intraguild prey. In this work we investigate some theoretical aspects about these interactions. First we analyse an experiment with predatory mites which was carried to test patterns of exclusion along a productivity gradient, predicted by theory. Although this experiment was carefully designed to test the theoretical assertions, their results do not agree with theory. Through a very simple model for intraguild predation which serves as a representation of that system, we show that: if the short-term dynamics is taken into account rather than only equilibrium states, in which the usual theory is based, and we consider that populations that attain levels very close to zero are extinct, experimental results meet theory. Then we study questions concerning the influence of different life stages of individuals on the dynamics of intraguild predation. We introduce a model with stage structure in both consumers and consider predation occurring only from adults of the intraguild predator on juveniles of the intraguild prey. This stage dependent interaction was believed t ohave great effects on the dynamics, once predation pressure on the intraguild prey is reduced, and has been proposed as one feature that could promote coexistence. We check the outcomes of the system along a productivity gradient and show that stage structure do not induce great qualitative changes on the dynamics and the more likely resulting dynamics continues being the extinction of one of the consumers... (Complete abstract click electronic access below) / Mestre

Tao, Yin = 納米線在液晶中的動力學 / 陶寅. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references. / Abstracts in English and Chinese. / Tao, Yin = Na mi xian zai ye jing zhong de dong li xue / Tao Yin. / Abstract --- p.I / 摘要 --- p.III / Acknowledgement --- p.IV / List of Figures --- p.VIII / List of Tables --- p.XV / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1. --- Background --- p.1 / Chapter 1.2. --- Review of Liquid Crystals --- p.2 / Chapter 1.2.1. --- Basic concepts --- p.2 / Chapter 1.2.2. --- Physical Properties of liquid crystals --- p.5 / Chapter 1.3. --- Manipulation of nanowires in suspensions --- p.8 / Chapter 1.3.1. --- Longitudinal Anchoring of liquid crystals --- p.8 / Chapter 1.3.2. --- Dielectrophoretic force and torque --- p.12 / Chapter 1.3.3. --- Measurement of conductivity --- p.15 / Chapter 1.4. --- Our motivation and work --- p.17 / Reference --- p.19 / Chapter Chapter 2 --- Experiments --- p.22 / Chapter 2.1. --- Nematic Liquid Crystal Cell Design and Fabrication --- p.22 / Chapter 2.1.1. --- Parallel Plate Capacitor like Liquid Crystal Cell --- p.22 / Chapter 2.1.2. --- In-Plane Switching Liquid Crystal Cell --- p.23 / Chapter 2.2. --- Filling of liquid crystals and dispersing nanowires --- p.28 / Chapter 2.3. --- Measurements --- p.30 / Chapter 2.3.1. --- Measurement of alignment and reorientation of the nanowires --- p.30 / Chapter 2.3.2. --- Measurements of the optical transmittance of liquid crystal cell --- p.31 / Chapter 2.4. --- Experimental Procedures --- p.33 / Chapter 2.4.1. --- Study of the relaxation of liquid crystals and nanowires --- p.33 / Chapter 2.4.2. --- Study of response of liquid crystals and nanowires to applied E field --- p.34 / Reference --- p.35 / Chapter Chapter 3 --- Numerical simulations of the motion of liquid crystals --- p.36 / Chapter 3.1. --- Leslie-Ericsson equation --- p.36 / Chapter 3.2. --- Response and relaxation of liquid crystals --- p.39 / Chapter 3.2.1. --- Parallel plate capacitor like liquid crystal cells --- p.39 / Chapter 3.2.2. --- In-plane switching liquid crystal cells --- p.45 / Reference --- p.49 / Chapter Chapter 4 --- Method of analysis --- p.50 / Chapter 4.1. --- Deduction of the orientation of nanowires --- p.50 / Chapter 4.1.1. --- Parallel plate capacitor like liquid crystal cell --- p.50 / Chapter 4.1.2. --- In-plane switching liquid crystal cells --- p.52 / Chapter 4.2. --- Methods of curve fitting to experimental data --- p.54 / Chapter 4.2.1. --- Procedures of fitting the curves of transmission --- p.54 / Chapter 4.2.2. --- Procedures of fitting the curves of angle β (t) and φ (t)…… --- p.57 / Reference --- p.64 / Chapter Chapter 5 --- Results and discussion --- p.65 / Chapter 5.1. --- Study of the relaxation of nanowires and liquid crystals --- p.65 / Chapter 5.1.1. --- Dependence on the length of nanowires --- p.65 / Chapter 5.1.2. --- Dependence on the temperature of liquid crystals --- p.82 / Chapter 5.2. --- Study of the responses of nanowires and liquid crystals to E field --- p.89 / Chapter 5.2.1. --- Dependence on the applied E field --- p.89 / Chapter 5.2.2. --- Dependence on the length of nanowires --- p.112 / Chapter 5.2.3. --- Dependence on the temperature of liquid crystal --- p.116 / Reference --- p.122 / Chapter Chapter 6 --- Conclusions --- p.123 / Appendix 1 --- p.125 / Appendix 2 --- p.132

The role of dynamical systems in general equilibrium analysis is chronicled. Starting with the introduction of a suitable phase space and evolution model, fundamental existence and stability results are proved. From here, many negative statements regarding the convergence of the price mechanism and attempts to rectify these conclusions are examined. The conclusion is that either the traditional economic hypotheses behind the model need to be reexamined or the economist’s dream of a universal pricing mechanism must be abandoned.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Le monde des Véhicules à Deux Roues Motorisés (VDRM) a changé considérablement,en matière de qualité et de performances. Ces véhicules ont pris une place importante dans notre vie quotidienne, que ce soit pour les déplacements ou les loisirs, ce qui a contribué à l’augmentation et à la diversité du parc. Néanmoins, la sécurité des usagers est devenue une des préoccupations des institutions routières et des organismes de recherche, vu le nombre croissant des accidents et la vulnérabilité à laquelle sont confrontés. Nos travaux de recherche s’inscrivent dans la thématique d’étude (modélisation et observation) et d’analyse de la dynamique limite des VDRM. L’objectif étant la conception des outils nécessaires à l’établissement de systèmes d’aide à la conduite, de type préventif, dédiés à renforcer la sécurité du conducteur et à améliorer sa conduite. Le principal outil est un bon dispositif de simulation, vu les contraintesrencontrées pour la réalisation en pratique des tests, tel que la sécurité du pilote, le coût, etc. C’est ainsi, qu’une synthèse de trois modèles dynamiques non linéaires, àun corps, à deux corps et à cinq corps, est proposée. Une fonction de risque, relativeà l’angle de roulis du véhicule maximal, est établie. Sa variation en fonction desparamètres inertiels et géométriques de l’ensemble véhicule et conducteur, de leursdynamiques et de l’infrastructure, a fait l’objet d’une étude approfondie. La difficultéd’implémentation de nombreux capteurs, nous a conduit à concevoir des méthodesd’observation des dynamiques importantes pour la mise en pratique des systèmesde sécurité. Pour ce faire, nous avons reconstruit les grandeurs, contribuant à la dynamique latérale, par l’application de l’observateur Proportionnel Double Intégral(P2I) sur deux cas de modèles (3DDL et 4 DDL). La dernière partie du mémoire, est consacrée aux travaux réalisés sur l’instrumentation du prototype Scooter dont dispose le laboratoire. L’analyse des données enregistrées sur piste et la validation des techniques d’observation développées y sont détaillées. / The world of Powered Two Wheeled (PTW) vehicles has changed considerably in quality and performance. These vehicles have taken an important place in our live, whether for transportation or leisure, which contributed to the increasing and diversity of their park. However, the safety of users has become a concern of road institutions and research organizations, given the increasing number of accidents and vulnerability at which they are faced. Our research fall within the thematic study of modeling, observation and dynamic limit analysis of the PTW vehicles. The main objective is to design tools needed to establish safety systems, of preventive kind, dedicated to enhance driver safety and improve his conduct. The main tool is a good device simulation, given the constraints encountered in the practical realization of tests, such as driver safety, cost, etc. For this, a synthesis of three non-linear dynamic models of one body, two bodies and five bodies, is proposed. A risk function relative to the maximum roll angle of the vehicle is established. Its variation according to the inertial and geometric parameters of the whole vehicle and driver, their dynamics and infrastructure, has been subject of extensive study. The difficulty of implementing many sensors has led us to develop methods to reconstruct the important dynamics for the implementation of safety systems. To do this, we reconstructed quantities contributing to the lateral dynamics by applying the Proportional Two Integral (P2I) observer. The last part of the manuscript is devoted to the work carried out about the instrumentationof the Scooter prototype, available at our laboratory. The analysis of the recorded data on the test track and the validation of the observers developed are detailed.

Advances in computational power and expanded access to computing clusters has made mathematical modeling of complex wave effects possible. We have used multi-core and cluster computing to implement analytical and numerical models of ultrasonic wave scattering in fluid and solid media (acoustic and elastic waves). We begin by implementing complicated analytical equations that describe the force upon spheres immersed in inviscid and viscous fluids due to an incident plane wave. Two real-world applications of acoustic force upon spheres are investigated using the mathematical formulations: emboli removal from cardiopulmonary bypass circuits using traveling waves and the micromanipulation of algal cells with standing waves to aid in biomass processing for algae biofuels. We then move on to consider wave scattering situations where analytical models do not exist: scattering of acoustic waves from multiple scatterers in fluids and Lamb wave scattering in solids. We use a numerical method called finite integration technique (FIT) to simulate wave behavior in three dimensions. The 3D simulations provide insight into experimental results for situations where 2D simulations would not be sufficient. The diverse set of scattering situations explored in this work show the broad applicability of the underlying principles and the computational tools that we have developed. Overall, our work shows that the movement towards better availability of large computational resources is opening up new ways to investigate complicated physics phenomena.

In order to perform useful tasks for us, robots must have the ability to notice, recognize, and respond to objects and events in their environment. This requires the acquisition and synthesis of information from a variety of sensors. Here we investigate the performance of a number of sensor modalities in an unstructured outdoor environment, including the Microsoft Kinect, thermal infrared camera, and coffee can radar. Special attention is given to acoustic echolocation measurements of approaching vehicles, where an acoustic parametric array propagates an audible signal to the oncoming target and the Kinect microphone array records the reflected backscattered signal. Although useful information about the target is hidden inside the noisy time domain measurements, the Dynamic Wavelet Fingerprint process (DWFP) is used to create a time-frequency representation of the data. A small-dimensional feature vector is created for each measurement using an intelligent feature selection process for use in statistical pattern classification routines. Using our experimentally measured data from real vehicles at 50 m, this process is able to correctly classify vehicles into one of five classes with 94% accuracy. Fully three-dimensional simulations allow us to study the nonlinear beam propagation and interaction with real-world targets to improve classification results.