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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Some aspects of the geometry of Poisson dynamical systems

Narayanan, Vivek 30 March 2011 (has links)
Not available / text
2

The C*-algebras associated with irrational time homeomorphisms of suspensions /

Itzá-Ortiz, Benjamín A., January 2003 (has links)
Thesis (Ph. D.)--University of Oregon, 2003. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 68-69). Also available for download via the World Wide Web; free to University of Oregon users.
3

General monotonicity, interpolation of operators, and applications

Unknown Date (has links)
Assume that {φn} is an orthonormal uniformly bounded (ONB) sequence of complex-valued functions de ned on a measure space (Ω,Σ,µ), and f ∈ L1(Ω,Σ,µ). Let be the Fourier coefficients of f with respect to {φn} . R.E.A.C. Paley proved a theorem connecting the Lp-norm of f with a related norm of the sequence {cn}. Hardy and Littlewood subsequently proved that Paley’s result is best possible within its context. Their results were generalized by Dikarev, Macaev, Askey, Wainger, Sagher, and later by Tikhonov, Li yand, Booton and others.The present work continues the generalization of these results. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
4

Kicks and Maps A different Approach to Modeling Biological Systems

Unknown Date (has links)
Modeling a biological systems, is a cyclic process which involves constructing a model from current theory and beliefs and then validating that model against the data. If the data does not match, qualitatively or quantitatively then there may be a problem with either our beliefs or the current theory. At the same time directly finding a model from the existing data would make generalizing results difficult. A considerable difficultly in this process is how to specify the model in the first place. There is a need to be practice which accounts for the growing use of mathematical and statistical methods. However, as a systems becomes more complex, standard mathematical approaches may not be sufficient. In the field of ecology, the standard techniques involve discrete maps, and continuous models such as ODE's. The intent of this work is to present the mathematics necessary to study hybrids of these two models, then consider two case studies. In first case we con sider a coral reef with continuous change, except in the presence of hurricanes. The results of the data are compared quantitatively and qualitatively with simulation results. For the second case we consider a model for rabies with a periodic birth pulse. Here the analysis is qualitative as we demonstrate the existence of a strange attractor by looking at the intersections of the stable and unstable manifold for the saddle point generating the attractor. For both cases studies the introduction of a discrete event into a continuous system is done via a Dirac Distribution or Measure. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection
5

Implementação de simulador de fluidodinâmica em meso-escala com o método DPD / Implementation of fluid dynamics simulator in meso-scale with the DPD method

Horta, Agnus Azevedo, 1967- 26 August 2018 (has links)
Orientador: Luiz Otávio Saraiva Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-26T05:32:16Z (GMT). No. of bitstreams: 1 Horta_AgnusAzevedo_M.pdf: 4762311 bytes, checksum: 1bcc55cdb06dfc294f352fc1ac27c0ad (MD5) Previous issue date: 2014 / Resumo: Este trabalho tem como objetivo principal a implementação do motor de simulação de um framework de simulação com partículas, o motor de simulação utilizará o método DPD (Dissipative Particle Dynamics), baseando-se no paradigma de programação orientada a objeto (POO) e no uso de estruturas de dados otimizadas. O motor de simulação foi escrito em linguagem C++. A concepção do sistema foi realizada de forma a facilitar e promover a reutilização e manutenção do código. Buscou-se, também, a flexibilidade e generalização através do uso da linguagem Python na geração dos arquivos de entrada correspondentes a distribuição espacial das partículas, sendo utilizada a linguagem de marcação XML (eXtensible Markup Language) na estruturação dos arquivos resultantes da simulação. No final, o motor de simulação é avaliado aplicando o problema do fluxo de um fluído entre placas paralelas e o resultado comparado com os resultados obtidos no simulador Hoomd-Blue / Abstract: This work aims the implementation of the simulation of a simulation framework with particle engine, the simulation engine will use DPD (Dissipative Particle Dynamics) method, based on the paradigm of object oriented programming (OOP) and use optimized data structures. The simulation engine is written in C language ++. The system design was performed in order to facilitate and promote the reuse and maintainability of the code. Also, we sought flexibility and generalization through the use of Python in the generation of the input files corresponding to the spatial distribution of particles, (eXtensible Markup Language) XML markup being used in structuring the files resulting from the simulation. At the end, the simulation engine is the problem of applying rated flow of a fluid between parallel plates and the result compared with the results obtained in the simulation Hoomd-Blue / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica
6

Análise de estabilidade e estruturas lagrangianas coerentes em sistemas dinâmicos não suaves : aspectos teóricos e práticos / Stability analysis and langrangian coherent structures in nonsmooth dynamical systems : theoretical and practical aspects

Fazanaro, Filipe Ieda, 1980- 21 August 2018 (has links)
Orientadores: José Raimundo de Oliveira, Ignacio Bravo Muñoz / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-21T12:37:43Z (GMT). No. of bitstreams: 1 Fazanaro_FilipeIeda_D.pdf: 53323687 bytes, checksum: 76694b226ed99a337ecee1769ed9c4e0 (MD5) Previous issue date: 2012 / Résumén: Esta tesis tiene como objetivo la caracterización de sistemas dinámicos no lineales y abruptos. Se propone una nueva metodología para la estimación del espectro de Lyapunov capaz de superar las dificultades relacionadas en los sistemas basados en funciones lineales por partes sobre la aplicación de los métodos clásicos de cálculo (cuando se utiliza linealización local o análisis de series de las series temporales experimentales). Este enfoque, denominado como Dinámica de los Clones, realiza la estimación del espectro de Lyapunov y también mejora el estudio de las características topológicas relacionadas con los procesos de mezcla que dan lugar al comportamiento caótico. Este estudio se lleva a cabo utilizando las Estructuras Coherentes de Lagrange que pueden obtenerse a través de la construcción de un campo de Exponentes de Lyapunov de Tiempo Finito donde se puede identificar a las crestas (o las separatrices) que dan la posibilidad de identificar las distintas regiones de convergencia y divergencia del espacio de estados. Debido al hecho que esta tesis se desarrolla fundamentalmente bajo un ordenador, los aspectos prácticos involucrados en los experimentos numéricos necesarios, emplean algunos conceptos y herramientas de computación en paralelo. Esto último permitió la optimización de los algoritmos implementados. Por lo tanto, los experimentos se realizaron para verificar la eficacia del enfoque de las Dinámicas Clonadas para la caracterización del circuito de Chua, y también para obtener las Estructuras Coherentes de Lagrange que tienen relación con los modelos dinámicos capaces de generar atractores caóticos multiscroll / Resumo: Essa tese objetiva caracterizar sistemas dinâmicos não lineares não suaves. Para tal, é proposta uma nova abordagem de estimação do espectro de Lyapunov capaz de contornar as dificuldades intrínsecas aos sistemas estruturados por funções lineares por partes quando da aplicação de metodologias clássicas (baseadas em linearizações locais ou em análises de séries temporais). Essa abordagem possibilita a estimação do espectro de Lyapunov e, além disso, auxilia no estudo das características topológicas relacionadas aos processos de mistura que dão origem ao comportamento caótico. Essa linha de estudo é realizada através das Estruturas Lagrangianas Coerentes, as quais são obtidas pela construção de um campo de Expoentes de Lyapunov de Tempo Finito, onde é possível identificar cristas (ou separatrizes) que dividem regiões de convergência e de divergência no espaço de estados. Por se tratar de um trabalho basicamente computacional, essa tese contempla os aspectos práticos envolvidos para a realização dos experimentos numéricos através da utilização de alguns conceitos e ferramentas de computação paralela, o que possibilitou a otimização dos algoritmos implementados. Nesse sentido, os experimentos foram realizados de modo a verificar a eficácia da metodologia proposta para a caracterização do circuito de Chua e, ainda, foram obtidas as Estruturas Lagrangianas Coerentes para os modelos dinâmicos capazes de gerar atratores caóticos multiscroll / Abstract: This thesis aims to characterize non-smooth nonlinear dynamical systems. To accomplish this purpose, we propose a new approach for estimating the Lyapunov spectrum which is capable to overcome the intrinsic difficulties of classical methods (based on local linearization or time series analysis) when dealing with systems based on piecewise linear functions. This approach, called Cloned Dynamics, allows the estimation of the Lyapunov spectrum and also improves the study of the topological features related to the mixing processes that give rise to the chaotic behavior. This study is performed using the Lagrangian Coherent Structures which are obtained by the construction of a Finite Time Lyapunov Exponents field where it is possible to identify the ridges (or the separatrices) which divide the convergence and divergence regions of the state space. Due to the fact that this thesis is basically developed under a computer environment, the practical features involved in the numerical experiments employing some parallel computing concepts and tools are discussed, which allowed the optimization of the algorithms implemented. In this sense, experiments were performed to verify the effectiveness of the Cloned Dynamics approach for the characterization of the Chua's circuit, and also to obtain the Lagrangian Coherent Structures related to the dynamical models capable of generating multiscroll chaotic attractors / Doutorado / Automação / Doutor em Engenharia Elétrica

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