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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.
11

Estudo de fluxo de potencia com aplicação de metodos diretos na resolução de sistemas de equações lineares / Study of power flow with application of direct methods in the resolutions of systems of linear

Costa, Emerson Chagas 02 July 2008 (has links)
Orientador: Aurelio Ribeiro Leite de Oliveira / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-10T18:21:37Z (GMT). No. of bitstreams: 1 Costa_EmersonChagas_M.pdf: 3002139 bytes, checksum: 1caa6878e65459343f93aa39d2841fa3 (MD5) Previous issue date: 2008 / Resumo: Diante de um sistema elétrico de potência brasileiro, complexo e gigantesco, o presente trabalho trata do estudo de fluxo de potência, por meio de simulação com os sistemas de 30 e 118 barras da IEEE (Institute of Electrical and Electronics Engineers) com os métodos desacoplados e utilizando os métodos diretos de decomposições de matrizes...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: Considering a large-scale and complex Brazil electric power system, the present work concerns the study of power flows, through simulations with the 30 and 118 bus system of the IEEE (Institute of Electrical and Electronics Engineers) applying the uncoupled methods and the direct methods of matrix decomposition...Note: The complete abstract is available with the full electronic digital thesis or dissertations / Mestrado / Sistemas de Energia Eletrica / Mestre em Matemática Aplicada
12

Convergence of Asynchronous Jacobi-Newton-Iterations

Schrader, U. 30 October 1998 (has links)
Asynchronous iterations often converge under different conditions than their syn- chronous counterparts. In this paper we will study the global convergence of Jacobi- Newton-like methods for nonlinear equationsF x = 0. It is a known fact, that the synchronous algorithm converges monotonically, ifF is a convex M-function and the starting valuesx0 andy0 meet the conditionF x04 04F y0 . In the paper it will be shown, which modifications are necessary to guarantee a similar convergence behavior for an asynchronous computation.
13

Soluções analíticas e numéricas de equações não lineares com auxílio de recursos computacionais / Analytical and numerical solutions of nonlinear equations using computational resources

Silva, Diego Alves 19 December 2017 (has links)
O principal objetivo deste trabalho é apresentar técnicas de solução para equações não lineares. Especificamente, consideramos equações compostas por funções elementares, dentre elas polinomiais, racionais, trigonométricas, exponenciais e logarítmicas, e por operações algébricas de soma, subtração, multiplicação, divisão, potência e raiz. Exploramos técnicas de resolução analítica e numérica. Como não existem fórmulas resolventes de extensão geral, a técnica analítica consiste em aplicar operações elementares que nos levam a equações equivalentes (que têm a mesma solução) até que se consiga uma equação simples, de fácil resolução. Os métodos numéricos abrangem um conjunto maior de equações e obtêm uma aproximação para a solução por meio de um processo que gera uma sequência de aproximações. Entre os métodos numéricos estudados estão Bissecção, de Newton, das Secantes e do Ponto Fixo (ou Iteração Linear). Recursos Computacionais como calculadora, planilha eletrônica e o software Maxima foram utilizados com objetivo de automatizar os cálculos, tornando essa tarefa mais rápida, e também buscando extrair informações adicionais do processo de resolução como criar tabelas e traçar gráficos. Realizamos testes numéricos com equações de diversos graus de dificuldade. Observamos as vantagens, as desvantagens e as limitações de cada método e de cada recurso. / The goal of this work is to present solution techniques for nonlinear equations. Specifically, we consider equations compounded of elementary functions, among them polynomials, rational, trigonometric, exponential and logarithmic, and of algebraic operations of addition, subtraction, multiplication, division, power and root. We explore analytical and numerical resolution techniques. Since there are no general resolvent formulas, the analytic technique consists of applying elementary operations that lead to equivalent equations (which have the same solution) until a simple and easily to solve equation is obtained. Numerical methods cover a larger set of equations and obtain an approximation to the solution by a process which generates a sequence of approximations. Among the numerical methods we studied Bisection, Newton, Secant and Fixed Point (or Linear Iteration) methods. Computational resources such as calculator, spreadsheet and the software Maxima were used in order to automate calculations, making this task faster, as well as seeking for additional information from the resolution process, such as creating tables and graphics. We perform numerical tests, with equations of varying degrees of difficulty. We note the advantages, disadvantages and limitations of each method and resource.
14

Regularity for solutions of nonlocal fully nonlinear parabolic equations and free boundaries on two dimensional cones

Chang Lara, Hector Andres 22 October 2013 (has links)
On the first part, we consider nonlinear operators I depending on a family of nonlocal linear operators [mathematical equations]. We study the solutions of the Dirichlet initial and boundary value problems [mathematical equations]. We do not assume even symmetry for the kernels. The odd part bring some sort of nonlocal drift term, which in principle competes against the regularization of the solution. Existence and uniqueness is established for viscosity solutions. Several Hölder estimates are established for u and its derivatives under special assumptions. Moreover, the estimates remain uniform as the order of the equation approaches the second order case. This allows to consider our results as an extension of the classical theory of second order fully nonlinear equations. On the second part, we study two phase problems posed over a two dimensional cone generated by a smooth curve [mathematical symbol] on the unit sphere. We show that when [mathematical equation] the free boundary avoids the vertex of the cone. When [mathematical equation]we provide examples of minimizers such that the vertex belongs to the free boundary. / text
15

Αριθμητική επίλυση εξισώσεων και παρεμβολή μέσω υπολογιστή για την εκπαιδευτική διαδικασία / Numerical solution of equations an interpolation by computer for the educational process

Αντρέου, Αντρέας 31 July 2012 (has links)
Στα πλαίσια εκπόνησης της παρούσας διπλωματικής εργασίας πραγματοποιείται μια αναλυτική παρουσίαση των μεθόδων αριθμητικής επίλυσης εξισώσεων, ήτοι διχοτόμησης, Regula Falsi, τέμνουσας και Newton-Raphson, καθώς και των τύπων παρεμβολής των προς τα εμπρός και προς τα πίσω διαφορών των Newton-Gregory. Επίσης γίνεται παρουσίαση του αντίστοιχου λογισμικού προγράμματος εφαρμογής της εκπαιδευτικής διαδικασίας. Ο στόχος εδώ είναι η εφαρμογή υπολογιστικών συστημάτων, καθώς αναφέρεται σε λογισμικό εφαρμογής, των μεθόδων και των τύπων παρεμβολής, κατά την παράδοση του μαθήματος της Αριθμητικής Ανάλυσης I του Α' έτους σπουδών. Στην πρώτη ενότητα γίνεται λεπτομερής ανάλυση των τεσσάρων μεθόδων αριθμητικής επίλυσης εξισώσεων και των τύπων παρεμβολής. Η επόμενη ενότητα αναφέρεται στο λογισμικό πρόγραμμα, το οποίο έχει δημιουργηθεί στα πλαίσια της διπλωματικής εργασίας, καθώς επίσης και στον τρόπο εφαρμογής του κατά την διάρκεια της διδασκαλίας. Και τέλος, στην τρίτη ενότητα γίνεται εικονογραφημένη παρουσίαση του λογισμικού προγράμματος. / In this Thesis, the numerical methods of bisection, Regula Falsi, secant and Newton-Raphson for solving nonlinear equations, as well as the forward and backward differences interpolation formulae of Newton-Gregory are presented in detail with emphasis on the educational procedure. The corresponding software application program for the educational process is also given. The aim is to present the application of the above methods of Numerical Analysis to first year students in Mathematics. The first section presents the analysis of the four numerical methods for solving equations and the two interpolation formulae. The second section refers to the software program, which has been developed as part of the thesis, in order to be applied during teaching the course. Finally, the third section is a representation of the software program.
16

Convite às equações diofantinas: uma abordagem para a educação básica

Altino da Silva Neto 24 August 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta dissertação, apresentamos os resultados de uma ampla pesquisa bibliográfica sobre as equações diofantinas e seus métodos de solução mais utilizados. A mais simples desta classe de equações é a da forma ax + by = c, com a, b e c números inteiros e ab 6= 0, chamada equação diofantina linear nas duas incógnitas x e y. No trabalho, expomos diversos métodos de resolução destas equações, em duas e três incógnitas. Para tanto, utilizamos conceitos de divisibilidade, divisão euclidiana, máximo divisor comum, números primos, dentre outros, que formam parte do currículo do Ensino Fundamental. No Brasil, as equações diofantinas não são comumente exploradas na Educação Básica, embora sejam perfeitamente compreensíveis nesse nível, como se mostra no texto do professor A. Guelfond, consultado na redação do trabalho. Na dissertação, incluímos, também, um capítulo sobre as contribuições de Diofanto para a Aritmética, que pode ser uma fonte de motivação para o estudo das equações diofantinas; e outro capítulo, ampliando as perspectivas sobre equações diofantinas não lineares. Esperamos que o trabalho seja uma fonte bibliográfica facilmente acessível aos professores da Educação Básica, e estimule seu interesse e criatividade para a introdução elementar desses conteúdos na prática docente e na preparação dos alunos para as Olimpíadas de Matemática. / In this dissertation, the results of a wide bibliographic research about Diophantine equations and their most used solution methods are exposed. The simplest equation of these class is the one in the form ax + by = c, with a, b and c integers numbers and ab 6= 0, called Diophantine linear equation in the unknowns x and y. Divers solutions methods for these equations, in two or three unknowns are discussed. Therefore, concepts like divisibility, Euclidean division, grated common divisor, prime numbers, among others, that are included in the Elementary Schools curriculum. In Brazil, Diophantine equations are not commonly exploited in Basic Education, even though they are perfectly understandable at this educational level, like Professor A. Guelfond shows in his book consulted in the redaction of the dissertation. There are also a chapter about Diophantuss contributions to Arithmetic, which can be a source of motivation to study the Diophantine equations; and another chapter, extending perspectives, about nonlinear Diophantine equations. We hope that the dissertation becomes a suitable easy accessible bibliographic font for Basic Education teachers and stimulates their interest and creativity for an elemental introducing of these contents in their teaching and in the students training for Math Olympiads.
17

Soluções analíticas e numéricas de equações não lineares com auxílio de recursos computacionais / Analytical and numerical solutions of nonlinear equations using computational resources

Diego Alves Silva 19 December 2017 (has links)
O principal objetivo deste trabalho é apresentar técnicas de solução para equações não lineares. Especificamente, consideramos equações compostas por funções elementares, dentre elas polinomiais, racionais, trigonométricas, exponenciais e logarítmicas, e por operações algébricas de soma, subtração, multiplicação, divisão, potência e raiz. Exploramos técnicas de resolução analítica e numérica. Como não existem fórmulas resolventes de extensão geral, a técnica analítica consiste em aplicar operações elementares que nos levam a equações equivalentes (que têm a mesma solução) até que se consiga uma equação simples, de fácil resolução. Os métodos numéricos abrangem um conjunto maior de equações e obtêm uma aproximação para a solução por meio de um processo que gera uma sequência de aproximações. Entre os métodos numéricos estudados estão Bissecção, de Newton, das Secantes e do Ponto Fixo (ou Iteração Linear). Recursos Computacionais como calculadora, planilha eletrônica e o software Maxima foram utilizados com objetivo de automatizar os cálculos, tornando essa tarefa mais rápida, e também buscando extrair informações adicionais do processo de resolução como criar tabelas e traçar gráficos. Realizamos testes numéricos com equações de diversos graus de dificuldade. Observamos as vantagens, as desvantagens e as limitações de cada método e de cada recurso. / The goal of this work is to present solution techniques for nonlinear equations. Specifically, we consider equations compounded of elementary functions, among them polynomials, rational, trigonometric, exponential and logarithmic, and of algebraic operations of addition, subtraction, multiplication, division, power and root. We explore analytical and numerical resolution techniques. Since there are no general resolvent formulas, the analytic technique consists of applying elementary operations that lead to equivalent equations (which have the same solution) until a simple and easily to solve equation is obtained. Numerical methods cover a larger set of equations and obtain an approximation to the solution by a process which generates a sequence of approximations. Among the numerical methods we studied Bisection, Newton, Secant and Fixed Point (or Linear Iteration) methods. Computational resources such as calculator, spreadsheet and the software Maxima were used in order to automate calculations, making this task faster, as well as seeking for additional information from the resolution process, such as creating tables and graphics. We perform numerical tests, with equations of varying degrees of difficulty. We note the advantages, disadvantages and limitations of each method and resource.
18

Optimalni višekoračni metodi NJutnovog tipa za nalaženje višestrukih korena nelinearne jednačine sa poznatom celobrojnom višestrukošću / Optimal multistep Newton-type methods for finding multiple roots of nonlinear equation with known integer multiplicity

Ćebić Dejan 16 January 2018 (has links)
<p>Ova disertacija se bavi problemom određivanja višestrukih rešenja realnih nelinearnih jednačina kada je višestrukost unapred poznati prirodan broj. Teorijski se analiziraju i numerički testiraju red konvergencije i optimalnost neki dobro poznatih metoda poput Liu-Čou metoda i Čou-Čen-Song metoda. Izvodi se i objašnjava zavisnost optimalnog reda konvergencije i parnosti/neparnosti višestrukosti rešenja. Takođe, konstruišu se dve nove familije postupaka osmog reda konvergecnije. Razmatraju se nove familije dvokoračnih postupaka namenjene za rešavanje problema koje klasični metodi NJutnovog tipa ne mogu da reše.</p> / <p>This thesis deals with the problem of determing multiple roots of real nonlinear equations where the multiplicity is some integer known in advance. The convergence order and optimal properties of some well-known methods such as Liu-Zhou method and Zhou-Chen-Song method are theoretically analyzed and numerically tested. The dependence of optimal convergence order on multiplicity has been derived and explained. Further, two new efficient families of methods with optimal eighth convergence order have been constructed. Furthermore, some new families of two-step methods are considered to solve certain problems where the classical Newton-type methods fail.</p>
19

Ψηφιακός έλεγχος θερμικής διεργασίας

Κουτρούλη, Ελένη 22 September 2009 (has links)
Σε αυτήν την διπλωματική εργασία μελετήσαμε το σύστημα ελέγχου θερμοκρασίας και στάθμης νερού σε δεξαμενή. Αρχικά αναφέρουμε γενικά στοιχεία θεωρίας σχετικά με τον σχεδιασμό συστημάτων ελέγχου στον χώρο κατάστασης και πιο συγκεκριμένα αναλύουμε την μέθοδο ελέγχου με βάση την αυθαίρετη τοποθέτηση πόλων. Στην συνέχεια ασχολούμαστε μεμονωμένα με τον έλεγχο στάθμης νερού σε δεξαμενή. Περιγράφουμε το φυσικό σύστημα και την μονάδα ελέγχου την οποί α χρησιμοποιήσαμε στον χώρο του εργαστηρίου. Έπειτα από μια σειρά πειραμάτων τα οποία εκτελέσαμε και με βάση τις μετρήσεις τις οποίες πήραμε ,μπορέσαμε να υπολογίσουμε τα χαρακτηριστικά των επιμέρους ηλεκτρομηχανολογικών στοιχείων της πειραματικής μας διάταξης, όπως για παράδειγμα της αντλίας νερού, της μονάδας μέτρησης της στάθμης ,καθώς και τα χαρακτηριστικά της στατικής διεργασίας. Ομοίως πράξαμε και για τον έλεγχο θερμοκρασίας νερού σε δεξαμενή και έτσι μπορέσαμε να υπολογίσουμε τα χαρακτηριστικά του στοιχείου θέρμανσης. Στην συνέχεια, δίνουμε την περιγραφή του ολικού συστήματος ελέγχου στάθμης και θερμοκρασίας νερού σε δεξαμενή. Αφού εξάγουμε τις μαθηματικές εξισώσεις οι οποίες περιγράφουν το σύστημα στην μόνιμη κατάσταση, συμπεραίνουμε πως το σύστημα είναι μη γραμμικό. Σχεδιάζουμε το μη γραμμικό σύστημα στο Simulink και γράφοντας κατάλληλο κώδικα στο Matlab μπορέσαμε να γραμμικοποιήσουμε το σύστημά μας γύρω από ένα συγκεκριμένο σημείο λειτουργίας και το διακριτοποιήσαμε. Έπειτα, πάλι με την βοήθεια του λογισμικού προγράμματος Matlab σχεδιάσαμε έναν ελεγκτή με την μέθοδο τοποθέτησης πόλων και τον εφαρμόσαμε στο μη γραμμικό σύστημα για διάφορες τιμές πόλων και εξάγαμε τα συμπεράσματά μας από τα αντίστοιχα διαγράμματα όσων φορά την καλύτερη απόκριση του συστήματος. Την ίδια διαδικασία με παραπάνω εφαρμόσαμε και για ένα διαφορετικό σημείο λειτουργίας του συστήματος. / -
20

Estabilidade de soluções ondas viajantes periodicas para as equações de Boussinesq e de Korteweg - de Vries / Stability of periodic travelling wave solutions for the Boussinesq and Korteweg- de Vries equations

Paiva, Lynnyngs Kelly Arruda Saraiva de 24 June 2005 (has links)
Orientadores: Jaime Angulo Paiva, Marcia A. G. Scialom / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-04T09:39:02Z (GMT). No. of bitstreams: 1 Paiva_LynnyngsKellyArrudaSaraivade_D.pdf: 1499074 bytes, checksum: 7fef4b8257781913440ab95a338aedcc (MD5) Previous issue date: 2005 / Doutorado / Matematica / Doutor em Matemática

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