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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

Controle preditivo n?o linear baseado no modelo de Hammerstein com prova de estabilidade

Casillo, Danielle Simone da Silva 27 March 2009 (has links)
Made available in DSpace on 2014-12-17T14:54:52Z (GMT). No. of bitstreams: 1 DanielleSSC.pdf: 1582089 bytes, checksum: 60ca15361e82c560b730f3d2c8f4b062 (MD5) Previous issue date: 2009-03-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Predictive Controller has been receiving plenty attention in the last decades, because the need to understand, to analyze, to predict and to control real systems has been quickly growing with the technological and industrial progress. The objective of this thesis is to present a contribution for the development and implementation of Nonlinear Predictive Controllers based on Hammerstein model, as well as to its make properties evaluation. In this case, in the Nonlinear Predictive Controller development the time-step linearization method is used and a compensation term is introduced in order to improve the controller performance. The main motivation of this thesis is the study and stability guarantee for the Nonlinear Predictive Controller based on Hammerstein model. In this case, was used the concepts of sections and Popov Theorem. Simulation results with literature models shows that the proposed approaches are able to control with good performance and to guarantee the systems stability / O Controle Preditivo tem recebido muita aten??o nas ?ltimas d?cadas, visto que a necessidade de compreender, analisar, predizer e controlar sistemas reais tem crescido rapidamente com o avan?o tecnol?gico e industrial. O objetivo desta tese ? apresentar uma contribui??o para o desenvolvimento e implementa??o de Controladores Preditivos N?o lineares baseado no modelo de Hammerstein, bem como fazer uma avalia??o de suas propriedades. Neste caso, no desenvolvimento do Controlador Preditivo N?o Linear utiliza-se o m?todo de lineariza??o por degrau de tempo e ? introduzido um termo de compensa??o a fim de melhorar o desempenho do mesmo. A principal motiva??o desta tese ? o estudo e a prova da estabilidade para o Controlador Preditivo N?o Linear baseado no modelo de Hammerstein. Para isso utilizou-se os conceitos de setores e Crit?rio de Popov. Testes de simula??o com modelos da literatura mostram que as abordagens propostas s?o capazes de controlar com um bom desempenho e garantir a estabilidade dos sistemas
2

Análise de estabilidade de sistemas nebulosos via critério de Popov.

Maurício Gonçalves Santana Júnior 00 December 2003 (has links)
Esta dissertação objetiva estudar a estabilidade de sistemas com controladores nebulosos. A característica de saída desta classe de controladores é não linear, sendo, portanto, necessário lançar mão de métodos para análise de estabilidade para sistemas não lineares.O critério de Popov é um método de análise de estabilidade para sistemas não lineares, de aplicação prática mais simples, por utilizar análise gráfica (interpretação geométrica), sendo o método utilizado neste trabalho.Neste trabalho, há o interesse de se aplicar esse critério a sistemas que utilizam controladores nebulosos com implicação Mamdani, por ser esta, a implicação mais importante conhecida na literatura.Para controladores nebulosos com uma entrada e uma saída, apresenta-se um método de análise para a obtenção do valor da inclinação máxima da característica não linear de saída, sem a necessidade, porém, de se gerar essa característica por completo.Para sistemas que possuem um controlador nebuloso com duas variáveis de entrada e uma variável de saída, resultando numa superfície, como característica não linear de saída. Utilizando manipulações matemáticas e gráficas, nas equações de estado do sistema a controlar, e na característica não linear de saída do CN, pode-se aplicar o critério de Popov a sistemas com esta configuração.
3

Leningrad's modernists : studies in composition and musical thought, 1917-1932 /

Haas, David Edwin, January 1900 (has links)
Texte remanié de: Thesis--Philosophie. / Thèse parue précédemment sous le titre : "Form and line in the music and musical thought of Leningrad, 1917-1932" Contient des poèmes d' A. Blok en russe suivis de la trad. anglaise. Bibliogr. p. 285-292. Index.
4

Bases of relations in one or several variables : fast algorithms and applications / Bases de relation en une ou plusieurs variables : algorithmes rapides et applications

Neiger, Vincent 30 November 2016 (has links)
Dans cette thèse, nous étudions des algorithmes pour un problème de recherche de relations à une ou plusieurs variables. Il généralise celui de calculer une solution à un système d’équations linéaires modulaires sur un anneau de polynômes, et inclut par exemple le calcul d’approximants de Hermite-Padé ou d’interpolants bivariés. Plutôt qu’une seule solution, nous nous attacherons à calculer un ensemble de générateurs possédant de bonnes propriétés. Précisément, l’entrée de notre problème consiste en un module de dimension finie spécifié par l’action des variables sur ses éléments, et en un certain nombre d’éléments de ce module ; il s’agit de calculer une base de Gröbner du modules des relations entre ces éléments. En termes d’algèbre linéaire, l’entrée décrit une matrice avec une structure de type Krylov, et il s’agit de calculer sous forme compacte une base du noyau de cette matrice. Nous proposons plusieurs algorithmes en fonction de la forme des matrices de multiplication qui représentent l’action des variables. Dans le cas d’une matrice de Jordan,nous accélérons le calcul d’interpolants multivariés sous certaines contraintes de degré ; nos résultats pour une forme de Frobenius permettent d’accélérer le calcul de formes normales de matrices polynomiales univariées. Enfin, dans le cas de plusieurs matrices denses, nous accélérons le changement d’ordre pour des bases de Gröbner d’idéaux multivariés zéro-dimensionnels. / In this thesis, we study algorithms for a problem of finding relations in one or several variables. It generalizes that of computing a solution to a system of linear modular equations over a polynomial ring, including in particular the computation of Hermite- Padéapproximants and bivariate interpolants. Rather than a single solution, we aim at computing generators of the solution set which have good properties. Precisely, the input of our problem consists of a finite-dimensional module given by the action of the variables on its elements, and of some elements of this module; the goal is to compute a Gröbner basis of the module of syzygies between these elements. In terms of linear algebra, the input describes a matrix with a type of Krylov structure, and the goal is to compute a compact representation of a basis of the nullspace of this matrix. We propose several algorithms in accordance with the structure of the multiplication matrices which specify the action of the variables. In the case of a Jordan matrix, we accelerate the computation of multivariate interpolants under degree constraints; our result for a Frobenius matrix leads to a faster algorithm for computing normal forms of univariate polynomial matrices. In the case of several dense matrices, we accelerate the change of monomial order for Gröbner bases of multivariate zero-dimensional ideals.
5

Frequency domain analysis of feedback interconnections of stable systems

Maya Gonzalez, Martin January 2015 (has links)
The study of non-linear input-output maps can be summarized by three concepts: Gain, Positivity and Dissipativity. However, in order to make efficient use of these theorems it is necessary to use loop transformations and weightings, or so called ”multipliers”.The first problem this thesis studies is the feedback interconnection of a Linear Time Invariant system with a memoryless bounded and monotone non-linearity, or so called Absolute Stability problem, for which the test for stability is equivalent to show the existence of a Zames-Falb multiplier. The main advantage of this approach is that Zames–Falb multipliers can be specialized to recover important tools such as Circle criterion and the Popov criterion. Albeit Zames-Falb multipliers are an efficient way of describing non-linearities in frequency domain, the Fourier transform of the multiplier does not preserve the L1 norm. This problem has been addressed by two paradigms: mathematically complex multipliers with exact L1 norm and multipliers with mathematically tractable frequency domain properties but approximate L1 norm. However, this thesis exposes a third factor that leads to conservative results: causality of Zames-Falb multipliers. This thesis exposes the consequences of narrowing the search Zames-Falb multipliers to causal multipliers, and motivated by this argument, introduces an anticausal complementary method for the causal multiplier synthesis in [1].The second subject of this thesis is the feedback interconnection of two bounded systems. The interconnection of two arbitrary systems has been a well understood problem from the point of view of Dissipativity and Passivity. Nonetheless, frequency domain analysis is largely restricted for passive systems by the need of canonically factorizable multipliers, while Dissipativity mostly exploits constant multipliers. This thesis uses IQC to show the stability of the feedback interconnection of two non-linear systems by introducing an equivalent representation of the IQC Theorem, and then studies formally the conditions that the IQC multipliers need. The result of this analysis is then compared with Passivity and Dissipativity by a series of corollaries.
6

Commande h∞ à base de modèles non entiers / H∞ control of fractional order models

Fadiga, Lamine 12 June 2014 (has links)
Les études menées permettent d’étendre la méthodologie de commande H∞ aux modèles décrits par des équations différentielles faisant intervenir des ordres de dérivation non entiers. Deux approches sont proposées. La première consiste à réécrire le modèle non entier comme un modèle entier incertain afin de pouvoir utiliser les méthodes de commande H∞ développées pour les modèles entiers. La seconde approche consiste à développer des conditions LMI spécifiques aux modèles non entiers à partir de leur pseudo représentation d’état. Ces deux approches sont appliquées à l’isolation vibratoire d’un pont. / The general theme of the work enables to extend H∞ control methodology to fractional order models. Two approaches are proposed. The first one consists in rewriting the fractional order model as an uncertain integer order model in order to use existing H∞ control methods for integer order models. The second approach consists in developing specific LMI conditions for fractional order models based on their pseudo state space representation. These two approaches are applied to the vibratory isolation of a bridge.
7

Fast Order Basis and Kernel Basis Computation and Related Problems

Zhou, Wei 28 November 2012 (has links)
In this thesis, we present efficient deterministic algorithms for polynomial matrix computation problems, including the computation of order basis, minimal kernel basis, matrix inverse, column basis, unimodular completion, determinant, Hermite normal form, rank and rank profile for matrices of univariate polynomials over a field. The algorithm for kernel basis computation also immediately provides an efficient deterministic algorithm for solving linear systems. The algorithm for column basis also gives efficient deterministic algorithms for computing matrix GCDs, column reduced forms, and Popov normal forms for matrices of any dimension and any rank. We reduce all these problems to polynomial matrix multiplications. The computational costs of our algorithms are then similar to the costs of multiplying matrices, whose dimensions match the input matrix dimensions in the original problems, and whose degrees equal the average column degrees of the original input matrices in most cases. The use of the average column degrees instead of the commonly used matrix degrees, or equivalently the maximum column degrees, makes our computational costs more precise and tighter. In addition, the shifted minimal bases computed by our algorithms are more general than the standard minimal bases.
8

Fast Order Basis and Kernel Basis Computation and Related Problems

Zhou, Wei 28 November 2012 (has links)
In this thesis, we present efficient deterministic algorithms for polynomial matrix computation problems, including the computation of order basis, minimal kernel basis, matrix inverse, column basis, unimodular completion, determinant, Hermite normal form, rank and rank profile for matrices of univariate polynomials over a field. The algorithm for kernel basis computation also immediately provides an efficient deterministic algorithm for solving linear systems. The algorithm for column basis also gives efficient deterministic algorithms for computing matrix GCDs, column reduced forms, and Popov normal forms for matrices of any dimension and any rank. We reduce all these problems to polynomial matrix multiplications. The computational costs of our algorithms are then similar to the costs of multiplying matrices, whose dimensions match the input matrix dimensions in the original problems, and whose degrees equal the average column degrees of the original input matrices in most cases. The use of the average column degrees instead of the commonly used matrix degrees, or equivalently the maximum column degrees, makes our computational costs more precise and tighter. In addition, the shifted minimal bases computed by our algorithms are more general than the standard minimal bases.
9

A historical survey of the non-Russian and foreign mission activity of the Russian Orthodox Church

Babiy, Alla Semionovna 01 January 2002 (has links)
Protestants often think that 1he ROC has no mission just because Orthodoxy pays to more attention to Service life. We tried to understand motives, goals and objectives of the ROC missionary activity. We found out that the ecclesiologic way of thinking was the basis missionary idea of the eastern missionary practice and it showed itself differently in special historical moments. This work divides the whole history of the Orthodox Church in Russia (XI - XX centuries) into 3 periods of mission and makes its brief survey and analysis. In the first period (XI-XVI) only single monks-colonialists realized the Great Commission among Finnish tribes and russifed it Only certain people used the methods of well planned contextualizating mission, like Stephen of Penn. During the second period (1552-middl.XIX) the ROC worked in close combination with the State to the detriment of the deep evangelization of natives. In the third period (the middle of XIX- the beginning of XX) the missionaries of Orthodox Missionary Society used all the achievements of the native and foreign missionary: contextualization, Liturgies in the national languages. enlightenment by schools of all levels, the training of national leaders, social work ets. At the present time, the ROC is renewing its own mission tradition after the sleep of the Soviet period. / Christian Spirituality, Church History and Missiology / M. Th. (Missiology)
10

A historical survey of the non-Russian and foreign mission activity of the Russian Orthodox Church

Babiy, Alla Semionovna 01 January 2002 (has links)
Protestants often think that 1he ROC has no mission just because Orthodoxy pays to more attention to Service life. We tried to understand motives, goals and objectives of the ROC missionary activity. We found out that the ecclesiologic way of thinking was the basis missionary idea of the eastern missionary practice and it showed itself differently in special historical moments. This work divides the whole history of the Orthodox Church in Russia (XI - XX centuries) into 3 periods of mission and makes its brief survey and analysis. In the first period (XI-XVI) only single monks-colonialists realized the Great Commission among Finnish tribes and russifed it Only certain people used the methods of well planned contextualizating mission, like Stephen of Penn. During the second period (1552-middl.XIX) the ROC worked in close combination with the State to the detriment of the deep evangelization of natives. In the third period (the middle of XIX- the beginning of XX) the missionaries of Orthodox Missionary Society used all the achievements of the native and foreign missionary: contextualization, Liturgies in the national languages. enlightenment by schools of all levels, the training of national leaders, social work ets. At the present time, the ROC is renewing its own mission tradition after the sleep of the Soviet period. / Christian Spirituality, Church History and Missiology / M. Th. (Missiology)

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