• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 3
  • Tagged with
  • 8
  • 8
  • 8
  • 5
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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

Um estudo sobre os sistemas de equaÃÃes lineares / A study on linear systems of equations

Carlos de Abreu RogÃrio da Silva 21 June 2014 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Historicamente o estudo de sistemas de equaÃÃes lineares precede o estudo de matrizes e determinantes. Seguiremos esta ordem e mostraremos que seguir o curso histÃrico à viÃvel e e dar significado preciso ao conceito de matriz e a definiÃÃo de determinante, os quais tÃm sidos imprecisos e incompreendido pela ordem estudada. Atualmente quase todos ou totalmente os livros didÃticos de MatemÃtica para o ensino mÃdio que abordam o tema tem adotado a seguinte ordem de estudo: matrizes, determinantes e sistemas de equaÃÃes lineares. Esta ordem tem tornado inviÃvel a compreensÃo dos conceitos de matriz e determinante por parte dos alunos e tambÃm dos professores que os ensinam. Essa prÃtica tem deixado prejuÃzos enormes na formaÃÃo dos alunos. Com uma abordagem simples e objetiva, introduzimos de maneira natural e sucessiva, os conceitos de: equaÃÃes lineares, sistema de equaÃÃes lineares, resoluÃÃo de sistemas de equaÃÃes lineares, determinante do sistema linear, matrizes e determinante de matrizes, sendo matrizes e determinantes considerados como ferramentas essenciais para o estudo e resoluÃÃo de sistema de equaÃÃes lineares. Acreditamos que essa ordem na abordagem pode servir para a melhoria do processo ensino-aprendizagem. / The study of linear equation systems has historically preceded the study of matrixes and determinants. Following this order, we will show that the historical course is viable,and we will give precise significance to the concept of matrix and to the definition of determinant, which have been imprecise and misunderstood due to the order of study. Nowadays almost all of the mathematics high school textbooks which approach this theme have adopted the following order of study: matrixes, determinants, and linear equation systems. This order has made it impracticable for students and teachers to comprehend the concepts of matrix and determinant. This kind of practice has caused enormous damage in the education process of the students. With a simple and objective approach, we introduce in a natural and successive way the concepts of: linear equations, linear equation systems, resolution of linear equation systems, linear system determinant, matrixes, and determinant of matrixes, keeping in mind that matrixes and detetrminants are essential tools for the study and resolution of linear equation systems.We believe that this order of approach can improve the teaching-learning process.
2

On Verification Of Restricted Extended Affine Equivalence Of Vectorial Boolean Functions

Sinak, Ahmet 01 September 2012 (has links) (PDF)
Vectorial Boolean functions are used as S-boxes in cryptosystems. To design inequivalent vectorial Boolean functions resistant to known attacks is one of the challenges in cryptography. Verifying whether two vectorial Boolean functions are equivalent or not is the final step in this challenge. Hence, finding a fast technique for determining whether two given vectorial Boolean functions are equivalent is an important problem. A special class of the equivalence called restricted extended affine (REA) equivalence is studied in this thesis. We study the verification complexity of REA-equivalence of two vectorial Boolean functions for some types, namely types I to VI. We first review the verification of the REA-equivalence types I to IV given in the recent work of Budaghyan and Kazymyrov (2012). Furthermore, we present the complexities of the verification of REA-equivalence types I and IV in the case basic simultaneous Gaussian elimination method is used. Next, we present two new REA-equivalence types V and VI with their complexities. Finally, we give the algorithms of each type I to VI with their MAGMA codes.
3

Sistemas lineares: aplicações e propostas de aula usando a metodologia de resolução de problemas e o software GeoGebra / Linear systems: applications and classroom proposals using teaching methodology and GeoGebra software

Boccardo, Mateus Eduardo [UNESP] 25 September 2017 (has links)
Submitted by Mateus Eduardo Boccardo null (mateuseboccardo@hotmail.com) on 2017-10-16T21:58:41Z No. of bitstreams: 1 SISTEMAS LINEARES- APLICAÇÕES E PROPOSTAS DE AULA USANDO A METODOLOGIA DE RESOLUÇÃO DE PROBLEMAS E O SOFTWARE GEOGEBRA.pdf: 1649568 bytes, checksum: c2692aee302e29bada55e36958c6599b (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-10-18T18:37:19Z (GMT) No. of bitstreams: 1 boccardo_me_me_sjrp.pdf: 1649568 bytes, checksum: c2692aee302e29bada55e36958c6599b (MD5) / Made available in DSpace on 2017-10-18T18:37:19Z (GMT). No. of bitstreams: 1 boccardo_me_me_sjrp.pdf: 1649568 bytes, checksum: c2692aee302e29bada55e36958c6599b (MD5) Previous issue date: 2017-09-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Sistemas Lineares, mais precisamente, Sistemas de Equações Lineares, é ferramenta útil para a resolução de vários problemas práticos e importantes, por exemplo, problemas relacionados a tráfego de veículos, balanceamento de equações químicas, cálculo de uma alimentação diária equilibrada, circuitos elétricos e interpolação polinomial. Neste trabalho abordamos o conteúdo Sistemas Lineares, seus métodos de resolução, algumas de suas inúmeras aplicações, bem como a interpretação geométrica do conjunto solução de sistemas lineares em duas ou três variáveis. Apresentamos também, uma análise de como esse assunto é tratado em alguns documentos oficiais de ensino. Por fim, são expostas duas Propostas de Aula que foram elaboradas para alunos do Ensino Básico, uma para ser desenvolvida usando a Resolução de Problemas como metodologia de ensino (na abordagem de problemas sobre sistemas lineares) e outra, sobre a Interpretação Geométrica do conjunto solução de Sistemas Lineares, para ser realizada na Sala de Informática, utilizando o software GeoGebra. / Linear System, more precisely, System of Linear Equations, is a useful tool for their solution of several practical and important problems, for example problems related to vehicle traffic, balancing of chemical equations, elaboration healthy daily diet, electrical circuits and polynomial interpolation. In this work, we study Linear System, its methods of resolution, some of its numerous applications, as well as the geometric interpretation of the solution set of linear system in two or three variables. We also present an analysis of how this subject is treated in some official teaching documents. Finally, we present two Class Proposals that are elaborated for Basic Education students, one to be developed using Problem Solving as a teaching methodology (in the approach to problems on linear system) and another, on the Geometric Interpretation of the solution set of Linear System, to be held in the Computer Laboratory, using GeoGebra software.
4

Uma proposta do ensino de programação linear no ensino médio / A proposal of education of linear programming in secondary education

Lyra, Marcelo Simplicio de 02 July 2014 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-01-16T13:17:29Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Marcelo Simplício de Lyra - 2014.pdf: 2216498 bytes, checksum: e17b32a5feca5b8118ebc97a0684a160 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-01-16T13:45:49Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Marcelo Simplício de Lyra - 2014.pdf: 2216498 bytes, checksum: e17b32a5feca5b8118ebc97a0684a160 (MD5) / Made available in DSpace on 2015-01-16T13:45:49Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação - Marcelo Simplício de Lyra - 2014.pdf: 2216498 bytes, checksum: e17b32a5feca5b8118ebc97a0684a160 (MD5) Previous issue date: 2014-07-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This research presents a new approach that aims to introduce linear programming into the high school taking into account the teaching techniques, teacher and student profiles, and the flexibility of the curriculum. The context of the linear programming involves problems with two or three variables, since problems with many variables cannot be easily considered in a high school curriculum, especially due to the time required to solve such problems. The approach is developed under an algebraic point of view, in which the linear problem‟s solutions are obtained by a resolution of systems of linear equations. The approach also considers a numerical and computer simulation software, denominated Octave®, in order to solve those systems of linear equations and, consequently, this software may be used as a tool that allows extending such approach to solve linear programming problems with several decision variables. / Esta pesquisa apresenta uma proposta de introdução da programação linear no ensino médio levando em consideração os métodos de ensino, o perfil profissional do professor, o perfil do estudante e a flexibilização do currículo escolar. O contexto da programação linear envolve problemas de duas ou três variáveis, uma vez que problemas com mais variáveis podem não se adequar ao currículo do ensino médio, em especial pelo fator tempo. Parte-se de um desenvolvimento algébrico, em que as soluções do problema são obtidas por meio da resolução de vários sistemas de equações lineares. A proposta também inclui utilizar um software de simulação numérica e computacional, denominado Octave®, para a resolução dos vários sistemas lineares e, consequentemente, ser usado como uma estratégia para estender a proposta para problemas de programação linear com várias variáveis de decisão.
5

Estimating the Optimal Extrapolation Parameter for Extrapolated Iterative Methods When Solving Sequences of Linear Systems

Anderson, Curtis James January 2013 (has links)
No description available.
6

On Methods for Solving Symmetric Systems of Linear Equations Arising in Optimization

Odland, Tove January 2015 (has links)
In this thesis we present research on mathematical properties of methods for solv- ing symmetric systems of linear equations that arise in various optimization problem formulations and in methods for solving such problems. In the first and third paper (Paper A and Paper C), we consider the connection be- tween the method of conjugate gradients and quasi-Newton methods on strictly convex quadratic optimization problems or equivalently on a symmetric system of linear equa- tions with a positive definite matrix. We state conditions on the quasi-Newton matrix and the update matrix such that the search directions generated by the corresponding quasi-Newton method and the method of conjugate gradients respectively are parallel. In paper A, we derive such conditions on the update matrix based on a sufficient condition to obtain mutually conjugate search directions. These conditions are shown to be equivalent to the one-parameter Broyden family. Further, we derive a one-to-one correspondence between the Broyden parameter and the scaling between the search directions from the method of conjugate gradients and a quasi-Newton method em- ploying some well-defined update scheme in the one-parameter Broyden family. In paper C, we give necessary and sufficient conditions on the quasi-Newton ma- trix and on the update matrix such that equivalence with the method of conjugate gra- dients hold for the corresponding quasi-Newton method. We show that the set of quasi- Newton schemes admitted by these necessary and sufficient conditions is strictly larger than the one-parameter Broyden family. In addition, we show that this set of quasi- Newton schemes includes an infinite number of symmetric rank-one update schemes. In the second paper (Paper B), we utilize an unnormalized Krylov subspace frame- work for solving symmetric systems of linear equations. These systems may be incom- patible and the matrix may be indefinite/singular. Such systems of symmetric linear equations arise in constrained optimization. In the case of an incompatible symmetric system of linear equations we give a certificate of incompatibility based on a projection on the null space of the symmetric matrix and characterize a minimum-residual solu- tion. Further we derive a minimum-residual method, give explicit recursions for the minimum-residual iterates and characterize a minimum-residual solution of minimum Euclidean norm. / I denna avhandling betraktar vi matematiska egenskaper hos metoder för att lösa symmetriska linjära ekvationssystem som uppkommer i formuleringar och metoder för en mängd olika optimeringsproblem. I första och tredje artikeln (Paper A och Paper C), undersöks kopplingen mellan konjugerade gradientmetoden och kvasi-Newtonmetoder när dessa appliceras på strikt konvexa kvadratiska optimeringsproblem utan bivillkor eller ekvivalent på ett symmet- risk linjärt ekvationssystem med en positivt definit symmetrisk matris. Vi ställer upp villkor på kvasi-Newtonmatrisen och uppdateringsmatrisen så att sökriktningen som fås från motsvarande kvasi-Newtonmetod blir parallell med den sökriktning som fås från konjugerade gradientmetoden. I den första artikeln (Paper A), härleds villkor på uppdateringsmatrisen baserade på ett tillräckligt villkor för att få ömsesidigt konjugerade sökriktningar. Dessa villkor på kvasi-Newtonmetoden visas vara ekvivalenta med att uppdateringsstrategin tillhör Broydens enparameterfamilj. Vi tar också fram en ett-till-ett överensstämmelse mellan Broydenparametern och skalningen mellan sökriktningarna från konjugerade gradient- metoden och en kvasi-Newtonmetod som använder någon väldefinierad uppdaterings- strategi från Broydens enparameterfamilj. I den tredje artikeln (Paper C), ger vi tillräckliga och nödvändiga villkor på en kvasi-Newtonmetod så att nämnda ekvivalens med konjugerade gradientmetoden er- hålls. Mängden kvasi-Newtonstrategier som uppfyller dessa villkor är strikt större än Broydens enparameterfamilj. Vi visar också att denna mängd kvasi-Newtonstrategier innehåller ett oändligt antal uppdateringsstrategier där uppdateringsmatrisen är en sym- metrisk matris av rang ett. I den andra artikeln (Paper B), används ett ramverk för icke-normaliserade Krylov- underrumsmetoder för att lösa symmetriska linjära ekvationssystem. Dessa ekvations- system kan sakna lösning och matrisen kan vara indefinit/singulär. Denna typ av sym- metriska linjära ekvationssystem uppkommer i en mängd formuleringar och metoder för optimeringsproblem med bivillkor. I fallet då det symmetriska linjära ekvations- systemet saknar lösning ger vi ett certifikat för detta baserat på en projektion på noll- rummet för den symmetriska matrisen och karaktäriserar en minimum-residuallösning. Vi härleder även en minimum-residualmetod i detta ramverk samt ger explicita rekur- sionsformler för denna metod. I fallet då det symmetriska linjära ekvationssystemet saknar lösning så karaktäriserar vi en minimum-residuallösning av minsta euklidiska norm. / <p>QC 20150519</p>
7

Stability of finite element solutions to Maxwell's equations in frequency domain

Schwarzbach, Christoph 12 October 2009 (has links) (PDF)
Eine Standardformulierung der Randwertaufgabe für die Beschreibung zeitharmonischer elektromagnetischer Phänomene hat die Vektor-Helmholtzgleichung für das elektrische Feld zur Grundlage. Bei niedrigen Frequenzen führt der große Nullraum des Rotationsoperators zu einem instabilen Lösungsverhalten. Wird die Randwertaufgabe zum Beispiel mit Hilfe der Methode der Finiten Elemente in ein lineares Gleichungssystem überführt, äußert sich die Instabilität in einer schlechten Konditionszahl ihrer Koeffizientenmatrix. Eine stabilere Formulierung wird durch die explizite Berücksichtigung der Kontinuitätsgleichung erreicht. Zur numerischen Lösung der Randwertaufgaben wurde eine Finite-Elemente-Software erstellt. Sie berücksichtigt unter anderem unstrukturierte Gitter, räumlich variable, anisotrope Materialparameter sowie die Erweiterung der Maxwell-Gleichungen durch Perfectly Matched Layers. Die Software wurde anhand von Anwendungen in der marinen Geophysik erfolgreich getestet. Insbesondere demonstriert die Einbeziehung von Seebodentopographie in Form einer stetigen Oberflächentriangulierung die geometrische Flexibilität der Software. / The physics of time-harmonic electromagnetic phenomena can be mathematically described by boundary value problems. A standard approach is based on the vector Helmholtz equation in terms of the electric field. The curl operator involved has a large, non-trivial kernel which leads to an instable solution behaviour at low frequencies. If the boundary value problem is solved approximately using, e. g., the finite element method, the instability expresses itself by a badly conditioned coefficient matrix of the ensuing system of linear equations. A stable formulation is obtained by taking the continuity equation explicitly into account. In order to solve the boundary value problem numerically a finite element software package has been implemented. Its features comprise, amongst others, the treatment of unstructured meshes and piecewise polynomial, anisotropic constitutive parameters as well as the extension of Maxwell’s equations to the Perfectly Matched Layer. Successful application of the software is demonstrated with examples from marine geophysics. In particular, the incorporation of seafloor topography by a continuous surface triangulation illustrates the geometric flexibility of the software.
8

Stability of finite element solutions to Maxwell's equations in frequency domain

Schwarzbach, Christoph 10 August 2009 (has links)
Eine Standardformulierung der Randwertaufgabe für die Beschreibung zeitharmonischer elektromagnetischer Phänomene hat die Vektor-Helmholtzgleichung für das elektrische Feld zur Grundlage. Bei niedrigen Frequenzen führt der große Nullraum des Rotationsoperators zu einem instabilen Lösungsverhalten. Wird die Randwertaufgabe zum Beispiel mit Hilfe der Methode der Finiten Elemente in ein lineares Gleichungssystem überführt, äußert sich die Instabilität in einer schlechten Konditionszahl ihrer Koeffizientenmatrix. Eine stabilere Formulierung wird durch die explizite Berücksichtigung der Kontinuitätsgleichung erreicht. Zur numerischen Lösung der Randwertaufgaben wurde eine Finite-Elemente-Software erstellt. Sie berücksichtigt unter anderem unstrukturierte Gitter, räumlich variable, anisotrope Materialparameter sowie die Erweiterung der Maxwell-Gleichungen durch Perfectly Matched Layers. Die Software wurde anhand von Anwendungen in der marinen Geophysik erfolgreich getestet. Insbesondere demonstriert die Einbeziehung von Seebodentopographie in Form einer stetigen Oberflächentriangulierung die geometrische Flexibilität der Software. / The physics of time-harmonic electromagnetic phenomena can be mathematically described by boundary value problems. A standard approach is based on the vector Helmholtz equation in terms of the electric field. The curl operator involved has a large, non-trivial kernel which leads to an instable solution behaviour at low frequencies. If the boundary value problem is solved approximately using, e. g., the finite element method, the instability expresses itself by a badly conditioned coefficient matrix of the ensuing system of linear equations. A stable formulation is obtained by taking the continuity equation explicitly into account. In order to solve the boundary value problem numerically a finite element software package has been implemented. Its features comprise, amongst others, the treatment of unstructured meshes and piecewise polynomial, anisotropic constitutive parameters as well as the extension of Maxwell’s equations to the Perfectly Matched Layer. Successful application of the software is demonstrated with examples from marine geophysics. In particular, the incorporation of seafloor topography by a continuous surface triangulation illustrates the geometric flexibility of the software.

Page generated in 0.1388 seconds