This flash animation demonstrates the expansion of a 2 x 2 determinant by the basket weave method. It includes audio instruction and a short self-test at the end of the animation.

Thesis (Ph. D.)--University of Notre Dame, 2006. / Thesis directed by Steven M. Boker for the Department of Psychology. "December 2006." Includes bibliographical references (leaves 99-102).

Thesis (M.Sc.)--Memorial University of Newfoundland, 1995. / Typescript. Computer disk contains: Appendix A, Fortran programs. Bibliography: leaves 134-137. Also available online.

This flash animation demonstrates the expansion of a 2 x 2 determinant by the basket weave method. It includes audio instruction and a short self-test at the end of the animation.

Adaptive and smart systems are growing in popularity as we shift toward personalization as a culture. With progressive demands on energy efficiency, it is increasingly important to focus on the utilization of energy in a novel way. This thesis investigates a microelectromechanical system (MEMS) mirror with the express intent to provide flexibility in solid state lighting (SSL). By coupling the micromirror to an optical source, the reflected light may be reshaped and directed so as to optimize the overall illumination profile. In addition, the light may be redirected in order to provide improved signal strength in visible light communications (VLC) with negligible impact on energy demands. With flexibility and full analog control in mind, the design of a fully integrated tip-tilt-piston micromirror with an additional variable focus degree of freedom is outlined. Electrothermal actuators are used to both steer the light and tune the focal length. A detailed discussion of the underlying physics behind composite beams and thermal actuators is addressed. This leads directly into an overview of the two main mirror components, namely the segmented mirror and the deflection actuators. An in-depth characterization of the dynamics of the mirror is discussed including the linearity of the thermal response. Frequency domain analysis of such a system provides insight into tunable mechanical properties such as the resonant frequency and quality factor. The degenerate resonant modes can be separated significantly. It is shown that the frequency response may be tuned by straining specific actuators and that it follows a predictable pattern. As a result, the system can be scanned at increasingly large angles. In other words, coupled mechanical modes allow variable damping and amplification. A means to determine the level of coupling is examined and the mode shape variations are tracked as a function of the tuning parameters. Finally, the applications of such a device are explored and tested. Such applications include reliable signal-to-noise ratio (SNR) enhancements in VLC of 30 dB and color tunable steerable lights using laser diodes. A brief discussion of the implications of dynamic illumination and tunable systems is juxtaposed with an explanation behind the integration of an electrothermal micromirror and an all digital driver.

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Há mais de uma década os robôs paralelos têm atraído a atenção das comunidades acadêmica e industrial devido às suas vantagens potenciais sobre as arquiteturas predominantes - as seriais. Dentre estas vantagens, pode-se citar a leveza, as elevadas velocidades e acelerações e a capacidade de carga. A aplicação industrial mais promissora para estas arquiteturas alternativas de robôs são as operações \"pega-e-põe\", necessárias nas indústrias alimentícia, farmacêutica e de componentes eletrônicos. Neste trabalho apresenta-se um robô paralelo, concebido com a finalidade de realizar operações \"pega-e-põe\" no espaço bidimensional (plano). O objetivo principal é a análise dinâmica deste mecanismo, empregando o método de Kane, para a determinação dos torques dos atuadores e das forças de reação, causados pelo efeito dinâmico de sua movimentação, quando a garra esteja sujeita a esforços externos e realizando uma trajetória retilínea ou circular em movimento uniforme ou uniformemente variado. Para tanto, desenvolveu-se nesta dissertação a análise cinemática do robô, um estudo de possíveis trajetórias para a garra, o levantamento do espaço de trabalho, bem como a análise dinâmica correspondente. Incluiu-se também diversas simulações para caracterizar melhor suas propriedades. / For over a decade parallel robots have attracted the interest from academic and industrial communities due to their potential advantages over the predominant serial architecture. Among these advantages are the lighter weight and higher speeds, accelerations, and load capacity. The most promising industrial application for these alternative architectures are the pick-and-place operations, which are needed in food, pharmaceutical and electronics industries. We show here a parallel robot designed to perform pick-and-place operations in two dimensions , i.e., on a plane. The main goal is the dynamical analysis of this mechanism by means of the Kane method. We determine the torques of the actuators and the reaction forces caused by the dynamical effects of its movement, when its end-effector is subject to external load. The cases of uniform and accelerated movements, with either straight or circular trajectory, are considered. Therefore, in this dissertation we present the kinematics analysis of the robot, an analysis of possible end-effector trajectories, the workspace development, and the corresponding dynamical analysis. A few simulations are also included to better describe its properties.

M.Ing. / The performance and reliability of induced draft fans are of ever growing concarn in industry, especially in the power generation industry. The reliability and plant efficiency depend on the design conditions of all plant components. Induced draft fans handle high temperature flyash-laden flue gas, and are often plagued by mass-flow deficiencies and excessive vibration in fossil fuel powerplants [1]. In this research an existing induced-draft fan is analysed to investigate the occurrence of high stresses forming on the impeller, as these stresses lead to cracks appearing on the centre plate of the impeller. The basic approach used to address this problem is implementing the Finite Element Method starting with different cantilever beam configurations to simulate the connection of the blade with the centre plate. Geometries are kept constant to facilitate in the practical set-up implementation stage of the dissertation. The practical set-up is used to verify the results obtained from the Finite Element Method program, and it serves as a benchmark test for evaluating the further use of the chosen Finite Element Method program. A simplified Finite Element Method model is presented for the induced draft fan. Static and frequency analyses are done to determine the characteristics of the fan structure. Lastly an advanced dynamic analysis is done on the specific fan. Different ramp force functions are used to simulate different start-up curves for the fan. A conclusion will be drawn from the dissertation, and recommendations will be made for similar future research work.

Cette thèse se trouve à l'intersection de deux sujets de recherches en économie qui ont connus des développements récents : d'un côté, la modélisation et l'étude des réseaux économiques, de l'autre, la théorie du transport et ses applications en économie. Les quatre chapitres de cette thèse déclinent plusieurs résultats théoriques en lien avec ces deux sujets, en insistant sur leurs connections. Le premier chapitre modélise des contrats bipartites sur un marché décentralisé comme un problème de flux. Ce travail prouve l’existence d'un équilibre compétitif et discute son efficacité. Nous présentons des interprétations de ce modèle dans le cas où les biens sont indivisibles. Ces spécifications sont utilisées pour proposer un modèle du marché du prêt interbancaire. Dans le second chapitre, co-écrit avec Alfred Galichon et Larry Samuelson, nous prouvons un théorème de statiques comparatives monotones. Nous appliquons ensuite ce résultat à plusieurs modèles économiques classiques (modèles d'appariement, modèles hédoniques et problèmes de flux de coût minimum). Le troisième chapitre, co-écrit avec Alfred Galichon et Arthur Charpentier, présente des outils pour résoudre les problèmes d'appariement sur des réseaux de grandes dimensions avant de les mettre en pratique. Enfin le quatrième chapitre, co-écrit avec Rakesh Vohra, montre comment un assureur monopolistique peut utiliser les externalités entre agents - modélisées comme un réseau - pour maximiser ses revenus. Bien qu’exerçant le niveau d'effort optimal d'un point de vue social, tous les agents préfèrent l'équilibre précédant l'introduction de l'assureur. / This dissertation lies at the intersection of two fields of research in economics that have recently substantially developed: on the one hand, the modeling and study of economic networks, and on the other hand, transport theory and its applications in economics. The four chapters of this dissertation present theoretical results in relation with these two topics and put stress on their connections. The first chapter models bipartite contracts on a decentralized market as an equilibrium flow problem. We prove the existence of a competitive equilibrium outcome and discuss its effciency. We interpret this equilibrium in the case of indivisible commodities. As an illustration, we build a model for the overnight interbank loan market with counterparty risk and collateralization costs. In the second one, written in collaboration with Alfred Galichon and Larry Samuelson, we prove a monotone comparative statics theorem that we then apply to several classical economic models (matching models, min-cost flow problems and hedonic models). The third chapter is a joint work with Alfred Galichon and Arthur Charpentier. It presents tools to solve for matching problems on large geographic networks before applying them to examples. Finally, the fourth chapter, written with Rakesh Vohra, shows how a monopolistic insurer can use externalities between agents - modeled as a network - to maximize his profit. We show that a monopolistic insurer decreases the welfare of all agents.

Glass and the glass elements found thein way into almou all area sof human aktivity thanks to technological advances of the last 20 years. The are of construction i sof course no exeption, quite the contrary. These days it is difficult to imagine building without the glass element, whether it is a part of the interior or exterior. Yet the theory on this issue is at a very low level in the Czech Republic. The content of my work is static and dynamic analysis of structures of glass, when it is applied in practice, it will save money.