Universiẗat, Diss., 2004--Tübingen.

Universiẗat, Diss., 2004--Tübingen.

Th. 3e cycle--Méc. non linéaire et chronométrie--Besançon, 1980. N°: 334.

The biplanar bicycle is an experimental vehicle configuration that has been the focus of recent autonomous vehicle research at Virginia Tech. Although the vehicle can be advantageous due to its zero-radius turning and ability to traverse discontinuous terrain, one key disadvantage of the configuration is that it lacks a stable reference frame from which observations of the surroundings can be based. A solution to this problem is presented here in the form of actuators designed to actively control the oscillations of a reference frame. The orientation of a camera attached to a mast extended above the vehicle is specifically considered. Autonomous operation of the vehicle could utilize image processing to navigate, but the camera must maintain a fixed orientation for the data to be valid. The work presented examines not only the regulation of the reference frame, but also the effects of such regulation on the velocity response of the vehicle. Practical considerations such as sensors, actuators, cost, and complexity are addressed. Although this work is centered around the biplanar bicycle, similar approaches can be extended to orientation of an arbitrary body in space. / Master of Science

Orientador: Sandra Augusta Santos / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-16T08:38:37Z (GMT). No. of bitstreams: 1 Pereira_RicardoAlexandreAlves_M.pdf: 1562416 bytes, checksum: 5b626a8b83a97556be648d6eef873195 (MD5) Previous issue date: 2010 / Resumo: Este trabalho teve por objetivo produzir um texto didático que auxiliasse no estudo e na compreensão dos Problemas de Programação Linear (PPL). Procuramos diminuir o "degrau" que existe entre o Cálculo, a Geometria e a Álgebra Linear no tratamento desses problemas, utilizando uma linguagem clara e objetiva. Dessa forma, fizemos apenas as demonstrações dos resultados que julgamos essenciais. Trabalhamos com os principais conceitos e definições que envolvem os PPL (otimização, vetor gradiente, derivada direcional, máximos e mínimos sobre conjunto compacto, Multiplicadores de Lagrange, espaço de exigência, solução ótima, dualidade entre outros) fazendo sempre que possível contextualizações através de diversas aplicações. Finalizamos este texto com o Lema de Farkas, utilizando argumentos simples e lógicos para a sua demonstração, com o uso de cálculo e da álgebra linear / Abstract: This study aimed to produce a didactic text which would help in the study and understanding of Linear Programming Problems (LPP). We seek to reduce the "gap" that exists between the Calculus, Geometry and Linear Algebra in the treatment of such problem using a clear and objective language. Thus, we have included only the proofs of the results that we consider essential. We work with key concepts and definitions involving PPL (optimization, gradient vector, directional derivative, maximum and minimum on a compact set, Lagrange multipliers, space requirement, optimal solution, duality, among others) including wherever possible a contextualization through various applications. We finish this text with the Farkas' Lemma, using simple and logical arguments for their demonstration with the use of calculus and linear algebra / Mestrado / Matematica Aplicada / Mestre em Matemática Aplicada

No description available.

En construction navale militaire, les navires sont conçus pour résister à des menaces conventionnelles comme les mines ou les torpilles. Ces conceptions s’appuient sur des calculs aux explosions sous-marines lointaines qui sont bien maîtrisées aujourd’hui. Depuis la Seconde Guerre Mondiale, cette thématique a en effet bénéficié d’importants travaux de recherche. Ceux-ci ont abouti à des méthodes numériques robustes qui permettent de simuler l’essentiel des phénomènes caractérisant ces événements. Ces méthodes, utilisées en ingénierie, s’appuient cependant sur des hypothèses restrictives qui limitent leur champ d’application. Elles sont discriminantes si l’on souhaite simuler les explosions sous-marines en champ proche, caractérisées par des phénomènes fortement non-linéaires. Dans ce cadre, on adapte la méthode éléments finis Euler-Lagrange Multi-Matériaux avec Couplage Euler-lagrange, pour simuler ces problèmes. Les évolutions présentées dans la thèse s’articulent autour de deux points. (1) La méthode est développée en deux dimensions pour résoudre les problèmes 2D axisymétriques avec une rapidité et une précision accrues par rapport aux simulations 3D. (2) La projection des résultats 2D sur des grilles de calculs différentes 2D ou 3D est implémentée. Cette technique de projection permet de résoudre le problème complet par des phases successives dont la physique se situe sur des échelles de temps et d’espace très différentes, et qui nécessitent des maillages adaptés. Les développements effectués sont finalement intégrés dans le code de calcul LS-DYNA version 5.1.1, et validés pour les différentes phases du problème à partir de résultats théoriques et expérimentaux. / In military shipbuilding, ships are designed to withstand conventional threats such as mines or torpedoes. These designs are based on calculations of structural response to underwater explosions in far field, what is relatively well controlled today. The thematic of underwater explosions has indeed benefited from extensive research since the Second World War. This has resulted in robust numerical methods to simulate the main phenomena that characterize such events. These methods used in engineering are based on assumptions that limit their scope. These restrictions are discriminatory when we attempt to simulate underwater explosions in near field which are mainly nonlinear phenomena. In this context, the Multi-Material Arbitrary Lagrangian-Eulerian method with Euler-Lagrange coupling is chosen to simulate these problems. To make the method more easily applicable in engineering, its adaptation is based on two points. (1) Firstly the method is developed for two-dimensional cases in order to solve 2D axisymmetric problems with higher speed and accuracy compared to 3D simulations. (2) Then the projection of results from two-dimensional analysis on 2D or 3D grids is implemented. The projection from one grid to the other allows solving the whole problem through successive phases for physics on very different time scales and space scales, what necessitates adapted meshes. The developments are implemented in LS-DYNA code for the revised version 5.1.1 and validated for the different phases of the problem from theoretical and experimental results.

本論文旨在討論複空間上的特殊拉格朗日子流行的各種建構方法。這些方法主要自R. Harvey, B. Lawson, D. Joyce, R. Bryanl 以及M. Haskins這幾位數學家發展及研究. 本文側重於擁有不同類型對稱位的特殊拉格朗日子流行的結構方法, 其中包指於n維環面群及特殊正交群不變的例子，以及直紋特殊拉格朗日子流行。除此之外,本論文也會討論以上建構方法所給出的具體制子。最後, 本文亦會討論一種可以建構擁有高虧格鏈的特殊拉格朗日子流行的方法。 / This thesis gives a survey on constructions of special Lagrangian submanifolds in C[superscript n]. These construction methods are mainly studied by Harvey and Lawson, D. Joyce, R. Bryant and M. Haskins. We mainly focus on special Lagrangian submanifolds with different kinds of symmetries. These include local constructions of T[superscript n] --and SO(n)--invariant examples, and ruled examples. We also discuss explicit examples arose from those constructions. Besides local constructions, a global gluing construction of special Lagrangian submanifolds with high genus links is also discussed. / Detailed summary in vernacular field only. / Lam, Yi Chun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 97-99). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese. / Chapter 1 --- Introduction --- p.6 / Chapter 2 --- Preliminaries --- p.17 / Chapter 2.1 --- Special Lagrangian Geometry --- p.17 / Chapter 2.2 --- Special Legendrian Links --- p.23 / Chapter 2.3 --- Harmonic Maps --- p.25 / Chapter 2.4 --- Moment Maps --- p.28 / Chapter 2.5 --- Evolution Equation --- p.30 / Chapter 2.6 --- Background Materials from Analysis --- p.33 / Chapter 3 --- T[superscript n] invariant Special Lagrangian Submanifolds --- p.36 / Chapter 3.1 --- Basic Example --- p.36 / Chapter 3.2 --- U(1)[superscript n-2] invariant Special Lagrangian Cones in C[superscript n] --- p.37 / Chapter 3.2.1 --- General Construction --- p.37 / Chapter 3.2.2 --- Reduction of O.D.E. System --- p.40 / Chapter 3.2.3 --- The 3--dimensional Case --- p.48 / Chapter 4 --- SO(n)--invariant Special Lagrangian Submanifolds --- p.52 / Chapter 4.1 --- Basic Example --- p.52 / Chapter 4.2 --- Special Lagrangian Submanifolds with Fixed Loci --- p.54 / Chapter 4.2.1 --- Reduction to P.D.E --- p.55 / Chapter 4.2.2 --- The 3--Dimensional Case --- p.63 / Chapter 5 --- Ruled Special Lagrangian Submanifolds --- p.65 / Chapter 5.1 --- Normal Bundle of a Submanifold --- p.65 / Chapter 5.2 --- Twisted Normal Bundles --- p.69 / Chapter 5.3 --- The 3Dimensional Case --- p.72 / Chapter 5.3.1 --- Construction of Special Lagrangian Ruled 3-folds --- p.71 / Chapter 5.3.2 --- Explicit Examples --- p.75 / Chapter 5.4 --- Twisted Special Lagrangian Cones --- p.78 / Chapter 6 --- Other Constructions --- p.81 / Chapter 6.1 --- Analysis on U(1)invariant Special Lagrangian submanifolds --- p.81 / Chapter 6.1.1 --- Non-singular Solutions --- p.83 / Chapter 6.1.2 --- Existence of Singular Solutions --- p.84 / Chapter 6.1.3 --- Properties of Singular Solutions --- p.86 / Chapter 6.2 --- Harmonic Maps and Minimal Immersions --- p.87 / Chapter 6.3 --- Construction of Special Lagrangian 3-folds with High Genus Links --- p.92 / Bibliography --- p.97

Orientador: Waldyr Alves Rodrigues Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica "Gleb Wataghin" / Made available in DSpace on 2018-09-24T18:14:34Z (GMT). No. of bitstreams: 1 Fernandez_VirginiaVelma_M.pdf: 1617857 bytes, checksum: e92d0b54ec62eafa67720b74cdbe5f13 (MD5) Previous issue date: 1995 / Resumo: Neste trabalho estudamos um modelo de partícula clássica com spin proposto originalmente por Barut-Zanghi (1984); e reformulado no Formalismo do Fibrado de Clifford por Pavsic, Recami, Rodrigues Jr. (1993). Desenvolvemos alguns teoremas de conservação e observamos a consistência deste modelo de Barut-Zanghi com as leis de conservação; damos ainda alguns argumentos heurísticos que nos conduzem a uma apropriada Hamiltoniana / Abstract: In this work we study a model of classical particle with spin that was first originally suggested by Barut-Zanghi (1984); it has Recently translated into Clifford Fiber Bundle Formalism by Pavsic, Recami, Rodrigues Jr. (1993). We develop some conservation theorems and point out the consistency of Barut-Zanghi model within the conservation laws; we also set any heuristic arguments yielding to an appropriate Hamiltonian for this one / Mestrado / Física / Mestre em Física

The main focus of this thesis is to design effective trajectories with minimum energy consumption for underwater remotely operated vehicles (ROV) in the environment with ocean current. The complete motion behavior of the ROV includes surge, sway, heave, roll, pitch, and yaw. Both the surge and sway are easy to be influenced by ocean current. The basic mission for the ROV is always from one starting point to a desired target position. An optimum trajectory with the minimum energy consumption not only can make the best use of energy, but also can improve maneuver efficiency for either manual operation or automatic control. In order to solve this problem, the optimal theorem is applied. The Matlab simulation tool is employed to demonstrate the response and performance of the ROV using the proposed trajectories. In addition, the applicably operational range for the ROV can also be determined when thrust limits are considered. Such information presents the extreme maneuver capability of the ROV in the ocean current.