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Melo, Henrique Alves de. "Euler's formula in the plan and for polyhedra." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11431.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorPolyhedra are geometric solids formed by a finite number of polygons they can be convex or non-convex, regular or not regular. This work we make three demonstrations of Eulerâs theorem for polyhedra in one plane being used graphs. We will adopt preliminary definitions of polygons, polyhedra and graphs and make a brief study of the theorem before the demonstrations analysis when the theorem is valid and what conditions exist polyhedra, since the theorem is accepted. The work brings some applications in the form of questions in the theory presented.
Os poliedros sÃo sÃlidos geomÃtricos formados por uma quantidade finita de polÃgonos. Eles podem ser convexos ou nÃo convexos, regulares ou nÃo regulares . Neste trabalho fazemos trÃs demonstraÃÃes do teorema de Euler para poliedros no plano, sendo uma utilizado grafos. Adotaremos definiÃÃes preliminares de polÃgonos, poliedros e grafos e faremos um breve estudo do teorema antes das demonstraÃÃes analisado quando o teorema à valido em quais condiÃÃes existem os poliedros, uma vez que o teorema à aceito. O trabalho traz algumas aplicaÃÃes em forma de questÃes da teoria apresentada.
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Carvalho, Wesley da Silva. "Cálculo das fórmulas de Euler e Pick no geoplano e no GeoGebra." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6970.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
In this dissertation, we first state Euler's polyhedral formula for a set of points with Euler characteristic 2. We address the two known ways to prove Euler's Theorem: beginning with the classical proof by using Euclidian Geometry and afterwards we take the advantage of Spherical Geometry to give another proof. Furthermore, we address a version of Euler's formula for planar polyhedron, as well as, Pick's formula and the equivalence between Euler and Pick's formula. In the end, we provide application of Euler and Pick's formula, via two pedagogy tools Geoplano and GeoGebra, by giving examples to teach in classroom.
Esta dissertação trata inicialmente da Fórmula de Euler e de sua validade para os conjuntos de pontos com característica de Euler igual a 2. São feitas duas demonstrações da Fórmula de Euler, uma utilizando conceitos de Geometria Euclidiana e uma outra via Geometria Esférica, além da apresentação de uma versão para poliedros planos da Fórmula de Euler. Posteriormente, é apresentada a Fórmula de Pick para o cálculo de áreas de polígonos simples reticulados e sua relação de equivalência com a Fórmula de Pick para poliedros planos. Finalmente mostramos duas possibilidades de trabalho com a Fórmula de Pick, no Geoplano e no software GeoGebra.
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Gontijo, Helen Kássia Coelho. "Teorema de Euler em sala de aula." Universidade Federal de Goiás, 2014. http://repositorio.bc.ufg.br/tede/handle/tede/3876.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This work is based on the study of the polyhedrons and the Euler's Theorem, by applying strategies of teaching using the concrete material, provoking improvements in the reasoning and in the geometrical perception the Euler's Theorem. Not mentioning a bit of history of tracks already made by several mathematicians who have contributed to the study of geometry, where the ideas previously applied by them teach us and help every day. Going to the presentation of a few concepts and de nitions about polyhedrons, as well as the demonstration that exist only ve polyhedrons of Plato. We've tried to expose the demonstration of the Euler's Theorem, through two researchers, Adrien Marie Legendre and of the professor Zoroastro Azambuja Filho, considering them very interesting and easy to understand. However, in the perspective that going from the concrete one is an alternative to improve the quality of teaching, it has been selected the activity Geometry of cutting soaps , which is in an article of Ana Maria Kale , see at [10], and Geometry of straws , at [9], which are based on work experiences of the same author. Before the new technologies we have opted for the mathematical software Poly, available on http://www.peda.com/poly which allows a better visualization of polyhedrons of di cult construction. All these activities have been presented to the students of the second grade in the Secondary Education to verify the Euler's Theorem through concrete experiences, obtaining this way a useful and creative geometrical knowledge, conquering the students' participation and interest.
Este trabalho baseia-se no estudo dos Poliedros e o Teorema de Euler, aplicando estratégias de ensinar usando o material concreto, desencadeando melhoras no raciocínio e na percepção geométrica do Teorema de Euler. Não deixando de mencionar um pouco da história de caminhos já trilhados por vários matemáticos que contribuíram para o estudo da geometria, onde as ideias anteriormente aplicadas por eles nos ensinam e ajudam no dia-a-dia. Partindo então para apresentação de alguns conceitos e de nições sobre Poliedros, bem como a demonstração de que só existem cinco poliedros de Platão. Buscamos expor a demonstração do Teorema de Euler, por dois pesquisadores, Adrien Marie Legendre e do professor Zoroastro Azambuja Filho, considerando-as bem interessantes e de fácil compreensão. Contudo, na perspectiva de que partir do concreto é uma alternativa para melhorar a qualidade de ensino, foi selecionada a atividade Geometria dos cortes de sabão , que se encontra em um artigo de Ana Maria Kale , veja em [10] e Geometria de Canudos , em [9], que são fundamentados em experiências de trabalho da mesma autora. Frente às novas tecnologias optamos pelo uso do software matemático Poly, disponível em http://www.peda.com/poly, que permite uma melhor visualização de poliedros de difícil construção. Todas estas atividades foram apresentadas para os alunos do 2o ano do Ensino Médio para a veri cação do Teorema de Euler através de experiências concretas, obtendo assim um conhecimento geométrico criativo e útil, conquistando a participação e interesse dos estudantes.
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Silva, Hércules do Nascimento. "Poliedros Regulares no Ensino Médio." Universidade Federal da Paraíba, 2014. http://tede.biblioteca.ufpb.br:8080/handle/tede/8042.
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In this work we present a study of the regular polyhedra, comparing and discussing the concepts and de nitions given in the study of regular polyhedra in textbooks most widely used in Brazilian high schools. We prove the theorem of Euler, we calculate surface areas and volumes of regular polyhedra. Finally, we present some mathematical software that can be used by students and mathematics teachers in the spatial geometry classes as auxiliary material in the teaching and learning of this subject in the classroom.
Neste trabalho apresentamos um estudo sobre os poliedros regulares, comparando e discutindo os conceitos e as de nições que são dadas no estudo dos poliedros regulares nos livros didáticos mais utilizados nas escolas brasileiras de Ensino Médio. Provamos o teorema de Euler, calculamos áreas de superfícies e os volumes dos poliedros regulares. Por m, apresentamos alguns softwares matemáticos que podem ser utilizados pelos alunos e professores de Matemática nas aulas de geometria espacial como material auxiliar no processo de ensino e aprendizagem deste tema em sala de aula.
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Silva, Eduardo Alves da. "Formas ponderadas do Teorema de Euler e partições com raiz : estabelecendo um tratamento combinatório para certas identidades de Ramanujan." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/183163.
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O artigo Weighted forms of Euler's theorem de William Y.C. Chen e Kathy Q. Ji, em resposta ao questionamento de George E. Andrews, matemático estadunidense, sobre encontrar demonstrações combinatórias de duas identidades no Caderno Perdido de Ramanujan, nos mostra algumas formas ponderadas do Teorema de Euler sobre partições com partes ímpares e partes distintas via a introdução do conceito de partição com raiz. A propositura deste trabalho é envolta à apresentação de resultados sobre partições com raiz de modo a posteriormente realizar formulações combinatórias das identidades de Ramanujan por meio deste conceito, procurando estabelecer conexões com formas ponderadas do Teorema de Euler. Em particular, a bijeção de Sylvester e a iteração de Pak da função de Dyson são elementos primordiais para obtê-las.The article Weighted forms of Euler's theorem by William Y.C. Chen and Kathy Q. Ji in response to the questioning of George E. Andrews, American mathematician, about nding combinatorial proofs for two identities in Ramanujan's Lost Notebook shows us some weighted forms of Euler's Theorem on partitions with odd parts and distinct parts through the introduction of the concept of rooted partition. The purpose of this work involves the presentation of results on rooted partitions in order to make combinatorial formulations of Ramanujan's identities, seeking to establish connections with weighted forms of Euler's Theorem. In particular, the Sylvester's bijection and the Pak's iteration of the Dyson's map are primordial elements to obtain them.
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Justino, Gildeci José. "A característica de Euler." Universidade Federal da Paraíba, 2013. http://tede.biblioteca.ufpb.br:8080/handle/tede/7471.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This dissertation is focused on the Euler's theorem for polyhedra homeomorphic to the sphere. Present statements made by Cauchy, Poincaré and Legendre. As a consequence we show that there are only ve regular convex polyhedra, called polyhedra Plato.
Esta dissertação tem como tema central o Teorema de Euler para poliedros homeomorfos à esfera. Apresentamos demonstrações feitas por Cauchy, Poincaré e Legendre. Como consequência mostramos a existência de apenas cinco poliedros convexos regulares, os chamados poliedros de Platão.
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Parreira, José Roberto Penachia. "Poliedros e o Teorema de Euler." Universidade Federal de Goiás, 2014. http://repositorio.bc.ufg.br/tede/handle/tde/2970.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This work aims is to demonstrate the Euler's Theorem for polyhedra, given by the equation V A + F = 2, where V; A and F are the numbers of vertices, edges and faces, respectively, the polyhedron. A historical survey of the main characters who contributed to the theme was elaborated. De nitions and properties of polygons and polyhedra were given. The statements were constructed in three distinct ways. The rst by Cauchy, commented by Professor Elon Lages Lima. This statement is valid for any polyhedron homeomorphic to a sphere and has the path planning of the polyhedron withdrawing one of its faces. The second statement was prepared by the professor Zoroastro Azambuja Filho, valid for any convex polyhedron, and its path projection of the polyhedron on a plane and comparison of the internal angles of polygons with projection angles of the polygon faces. The third statements was presented by Legendre, also valid for any convex polyhedron, and its path in the projection of a spherical polyhedron surface. We use the Girard's Formula, the sum of the interior angles of a spherical triangle, to complete the demonstration. This work also suggests methods of applying the proof of Euler's Theorem in the classroom for high school students, and resolution of vestibular exercises involving the subject.
Este trabalho tem por objetivo a demonstra c~ao do Teorema de Euler para poliedros, dado pela equa ção V A + F = 2, onde V; A e F são os n úmeros de v értices, arestas e faces, respectivamente, do poliedro. Foi elaborada uma pesquisa hist orica dos principais personagens que contribuiram para o tema. Foram dadas de ni ções e propriedades de pol ígonos e poliedros. As demonstra ções foram constru ídas em três caminhos distintos. A primeira por Cauchy, comentada pelo professor Elon Lages Lima. Esta demonstra ção é v álida para qualquer poliedro homeomorfo a uma esfera e tem como caminho a plani fica ção do poliedro retirando-se uma de suas faces. A segunda demonstra c~ao foi elaborada pelo professor Zoroastro Azambuja Filho, v álida para qualquer poliedro convexo e tem como caminho a proje ção do poliedro num plano e a compara c~ao dos ângulos internos dos pol ígonos da proje ção com os ângulos dos pol gonos das faces. A terceira demonstra c~ao foi apresentada por Legendre, tamb ém v álida para qualquer poliedro convexo e tem como caminho a projeção do poliedro em uma superf ície esf érica. Utiliza-se a F ormula de Girard, da soma dos ângulos internos de um tri^angulo esf érico, para concluir a demonstra ção. Este trabalho tamb ém sugere metodologias de aplica ção da demonstração do Teorema de Euler em sala de aula, para alunos do Ensino M édio, e resolu ção de exercí cios de vestibulares envolvendo o tema.
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Reeder, Patrick F. "Internal Set Theory and Euler's Introductio in Analysin Infinitorum." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366149288.
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Paião, Ana Pedro Lemos. "Introduction to optimal control theory and its application to diabetes." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/16806.
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Mestrado em Matemática e AplicaçõesO Cálculo das Variações e o Controlo Ótimo são dois ramos da Matemática que estão muito interligados entre si e também com outras áreas. Como exemplo, podemos citar a Geometria, a Física, a Mecânica, a Economia, a Biologia, bem como a Medicina. Nesta tese estudamos vários tipos de problemas variacionais e de Controlo Ótimo, estabelecendo a ligação entre alguns destes. Fazemos uma breve introdução sobre a Diabetes Mellitus, uma vez que estudamos um modelo matemático que traduz a interação entre a glicose e a insulina no sangue por forma a otimizar o estado de uma pessoa com diabetes tipo 1.
The Calculus of Variations and the Optimal Control are two branches of Mathematics that are very interconnected with each other and with other areas. As example, we can mention Geometry, Physics, Mechanics, Economics, Biology and Medicine. In this thesis we study various types of variational problems and of Optimal Control, establishing the connection between some of these. We make a brief introduction to the Diabetes Mellitus, because we study a mathematical model that reflects the interaction between glucose and insulin in the blood in order to optimize the state of a person with diabetes type 1.
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Badar, Muhammad, and Ansir Iqbal. "Polya's Enumeration Theorem : Number of colorings of n-gons and non isomorphic graphs." Thesis, Linnaeus University, School of Computer Science, Physics and Mathematics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-6199.
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Polya’s theorem can be used to enumerate objects under permutation groups. Using grouptheory, combinatorics and some examples, Polya’s theorem and Burnside’s lemma arederived. The examples used are a square, pentagon, hexagon and heptagon under theirrespective dihedral groups. Generalization using more permutations and applications tograph theory.Using Polya’s Enumeration theorem, Harary and Palmer [5] give a function whichgives the number of unlabeled graphs n vertices and m edges. We present their work andthe necessary background knowledge.
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Cheng, Wing Kin. "Euler characteristic structure and weight homology /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?MATH%202004%20CHENGW.
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Cota, Andreia Caroline da Silva. "Euler e os n?meros pentagonais." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16078.
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Previous issue date: 2011-10-26The present investigation includes a study of Leonhard Euler and the pentagonal numbers is his article Mirabilibus Proprietatibus Numerorum Pentagonalium - E524. After a brief review of the life and work of Euler, we analyze the mathematical concepts covered in that article as well as its historical context. For this purpose, we explain the concept of figurate numbers, showing its mode of generation, as well as its geometric and algebraic representations. Then, we present a brief history of the search for the Eulerian pentagonal number theorem, based on his correspondence on the subject with Daniel Bernoulli, Nikolaus Bernoulli, Christian Goldbach and Jean Le Rond d'Alembert. At first, Euler states the theorem, but admits that he doesn t know to prove it. Finally, in a letter to Goldbach in 1750, he presents a demonstration, which is published in E541, along with an alternative proof. The expansion of the concept of pentagonal number is then explained and justified by compare the geometric and algebraic representations of the new pentagonal numbers pentagonal numbers with those of traditional pentagonal numbers. Then we explain to the pentagonal number theorem, that is, the fact that the infinite product(1 x)(1 xx)(1 x3)(1 x4)(1 x5)(1 x6)(1 x7)... is equal to the infinite series 1 x1 x2+x5+x7 x12 x15+x22+x26 ..., where the exponents are given by the pentagonal numbers (expanded) and the sign is determined by whether as more or less as the exponent is pentagonal number (traditional or expanded). We also mention that Euler relates the pentagonal number theorem to other parts of mathematics, such as the concept of partitions, generating functions, the theory of infinite products and the sum of divisors. We end with an explanation of Euler s demonstration pentagonal number theorem
O presente trabalho de pesquisa compreende em um estudo de Leonhard Euler sobre os n?meros pentagonais e o artigo Mirabilibus Proprietatibus Numerorum Pentagonalium -E524. Depois de uma breve revis?o da vida e obra de Euler, analisamos os conceitos matem?ticos abordados no referido artigo como tamb?m a sua contextualiza??o hist?rica. Para tanto, explicamos o conceito de n?meros figurados, mostrando seu modo de gera??o, bem como suas representa??es geom?tricas e alg?bricas. Em seguida, faz-se um pequeno hist?rico da busca euleriana para o Teorema dos N?meros Pentagonais, perpassando sua correspond?ncia sobre o assunto com Daniel Bernoulli, Nikolaus Bernoulli e Christian Goldbach. No in?cio, Euler afirma o teorema, por?m admite que n?o sabe demonstr?-lo. Finalmente, em uma carta ? Goldbach, de 1750, faz a procurada demonstra??o, a qual ? publicada em E541, junto ? demonstra??o alternativa. A expans?o do conceito de n?mero pentagonal ? ent?o explicada e justificada, tendo em vista a compara??o das representa??es geom?trica e alg?brica dos novos n?meros pentagonais com as dos n?meros pentagonais tradicionais. Em seguida, explana-se o Teorema dos N?meros Pentagonais, isto ?, o fato de que o produto infinito (1 x)(1 xx)(1 x 3)(1 x 4)(1 x 5)(1 x 6)(1 x 7) ... ser igual ? s?rie infinita 1 x 1 x 2+x 5+x 7 x 12 x 15+x 22+x 26 ..., onde os expoentes s?o dados pelos n?meros pentagonais (expandidos) e o sinal ? dado como mais ou menos conforme o expoente ? um n?mero pentagonal (seja tradicional, seja expandido) de ordem par ou ?mpar. Tamb?m mencionamos que Euler, utiliza os n?meros pentagonais e o referido teorema sobre outras partes da matem?tica, como: o conceito de parti??o, fun??es geradoras, a teoria do produto infinito e a soma de divisores. Finalizamos com uma explica??o da demonstra??o do Teorema dos N?meros Pentagonais.
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Karlsson, Jonas. "Modular forms and converse theorems for Dirichlet series." Thesis, Linköping University, Applied Mathematics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-19446.
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This thesis makes a survey of converse theorems for Dirichlet series. A converse theo-rem gives sufficient conditions for a Dirichlet series to be the Dirichlet series attachedto a modular form. Such Dirichlet series have special properties, such as a functionalequation and an Euler product. Sometimes these properties characterize the modularform completely, i.e. they are sufficient to prove the proper transformation behaviourunder some discrete group. The problem dates back to Hecke and Weil, and has morerecently been treated by Conrey et.al. The articles surveyed are:
- "An extension of Hecke's converse theorem", by B. Conrey and D. Farmer
- "Converse theorems assuming a partial Euler product", by D. Farmer and K.Wilson
- "A converse theorem for ¡0(13)", by B. Conrey, D. Farmer, B. Odgers and N.Snaith
The results and the proofs are described. The second article is found to contain anerror. Finally an alternative proof strategy is proposed.
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Hanson, Christopher J. (Christopher John) 1971. "Integrated lifting-surface and Euler/boundary-layer theory analysis method for marine propulsors." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/91328.
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Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (leaves 62-63).
by Christopher J. Hanson.
Nav.E.
S.M.
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Perera, Simon. "Grothendieck rings of theories of modules." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/grothendieck-rings-of-theories-of-modules(897cbbd9-77b6-47fb-8cf8-d15c7432e61b).html.
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We consider right modules over a ring, as models of a first order theory. We explorethe definable sets and the definable bijections between them. We employ the notionsof Euler characteristic and Grothendieck ring for a first order structure, introduced byJ. Krajicek and T. Scanlon in [24]. The Grothendieck ring is an algebraic structurethat captures certain properties of a model and its category of definable sets.If M is a module over a product of rings A and B, then M has a decomposition into a direct sum of an A-module and a B-module. Theorem 3.5.1 states that then the Grothendieck ring of M is the tensor product of the Grothendieck rings of the summands.Theorem 4.3.1 states that the Grothendieck ring of every infinite module over afield or skew field is isomorphic to Z[X].Proposition 5.2.4 states that for an elementary extension of models of anytheory, the elementary embedding induces an embedding of the corresponding Grothendieck rings. Theorem 5.3.1 is that for an elementary embedding of modules, we have the stronger result that the embedding induces an isomorphism of Grothendieck rings.We define a model-theoretic Grothendieck ring of the category Mod-R and explorethe relationship between this ring and the Grothendieck rings of general right R-modules. The category of pp-imaginaries, shown by K. Burke in [7] to be equivalentto the subcategory of finitely presented functors in (mod-R; Ab), provides a functorial approach to studying the generators of theGrothendieck rings of R-modules. It is shown in Theorem 6.3.5 that whenever R andS are Morita equivalent rings, the rings Grothendieck rings of the module categories Mod-R and Mod-S are isomorphic.Combining results from previous chapters, we derive Theorem 7.2.1 saying that theGrothendieck ring of any module over a semisimple ring is isomorphic to a polynomialring Z[X1,...,Xn] for some n.
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Calin, Ovidiu, and Chang Der-Chen. "The geometry on a step 3 Grushin model." Universität Potsdam, 2004. http://opus.kobv.de/ubp/volltexte/2008/2672/.
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In this article we study the geometry associated with the sub-elliptic operator ½ (X²1 +X²2), where X1 = ∂x and X2 = x²/2 ∂y are vector fields on R². We show that any point can be connected with the origin by at least one geodesic and we provide an approximate formula for the number of the geodesics between the origin and the points situated outside of the y-axis. We show there are in¯nitely many geodesics between the origin and the points on the y-axis.
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Mucelin, Cláudio. "Demonstrações bijetivas em partições." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306031.
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Orientador: Andréia Cristina RibeiroDissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica
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Resumo: Este trabalho apresenta alguns resultados sobre partições de números inteiros e a importância deles na história da Matemática e da Teoria dos Números. Encontrar demonstrações bijetivas em partições não é nada fácil. Mas, depois de encontradas, tornam-se uma maneira agradável e fácil de entender e provar algumas Identidades de Partições. Este trabalho pretende ser didático e de fácil entendimento para futuras pesquisas de estudantes que se interessem pelo assunto. Ele traz definições básicas e importantes sobre partições, os Gráficos de Ferrers, demonstrações de resultados interessantes como a Bijeção de Bressoud e o Teorema Pentagonal de Euler. Destaca também a importância das funções geradoras e alguns resultados devidos a Sylvester, Dyson, Fine, Schur e Rogers-Ramanujan
Abstract: This work presents some results about partitions of integers numbers and their importance in the history of Mathematics and in the Theory of the Numbers. To find bijective demonstrations in partitions it is not easy. But, after finding them, to understand and to prove some Identities of Partitions becomes agreeable and easy. This work intends to be didatic and of easy understanding for future researches made by students interested in this subject. It contains basic and important definitions about partitions, the Ferrers' Graphics, demonstrations of interesting results as the Bressond's Bijection and the Euler's Pentagonal Theorem. It also details the importance of the generating functions and some results due to Sylvester, Dyson, Fine, Schur and Rogers-Ramanujan
Mestrado
Teoria dos Numeros
Mestre em Matemática
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Gill, C. P. "Growth series of certain groups." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282568.
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Ayaz, Razmjooei. "Investigation of SomeCognitive Difficulties inSet Theory." Thesis, Stockholms universitet, Institutionen för matematikämnets och naturvetenskapsämnenas didaktik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-91976.
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A previous study on students approach to problems of Set Theory in Iran brought me somehypotheses. These encouraged me to test the hypotheses in this supplementary study. Mypurpose of this study was to consider some students' cognitive difficulties in Set Theory. Iinvestigated students’ conceptual understanding of two major concepts of Set Theory – theconcepts of inclusion and belonging. I also studied the ways students use Venn diagram tofigure out problems in Set Theory. I wanted to examine how students figure out the differentmeanings of words in the natural and formal language. To do so, I analyzed six experiments. Icompared three experiments with the experiments of my previous study in Iran. My researchquestions suggested using a qualitative research method. My theoretical framework built aroundtheories of semiotic activities, which were used in the analysis.The results indicated that students can make unfortunate use of Euler–Venn diagrams. A set ofsets was a difficult concept for students. Some words in natural language, even the word "set" inboth natural and formal language, caused confusion for students when introduced in Settheoretic contexts. Students failed sometimes to distinguish between sets and elements. Theexperiments showed that students’ cultural context had affect on students' cognition regardingmathematical objects.
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Backström, Daniel. "Modelling the flexural dynamics of sandwich beams using Bernoulli-Euler or Timoshenko theory with frequency dependent parameters /." Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-508.
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Leoncio, Sarah Mara Silva. "Os artigos de Euler sobre os n?meros amig?veis." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16094.
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Previous issue date: 2013-01-22Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Among the many methodological resources that the mathematics teacher can use in the classroom, we can cite the History of Mathematics which has contributed to the development of activities that promotes students curiosity about mathematics and its history. In this regard, the present dissertation aims to translate and analyze, mathematically and historically, the three works of Euler about amicable numbers that were writed during the Eighteenth century with the same title: De numeris amicabilibus. These works, despite being written in 1747 when Euler lived in Berlin, were published in different times and places. The first, published in 1747 in Nova Acta Eruditorum and which received the number E100 in the Enestr?m index, summarizes the historical context of amicable numbers, mentions the formula 2nxy & 2nz used by his precursors and presents a table containing thirty pairs of amicable numbers. The second work, E152, was published in 1750 in Opuscula varii argument. It is the result of a comprehensive review of Euler s research on amicable numbers which resulted in a catalog containing 61 pairs, a quantity which had never been achieved by any mathematician before Euler. Finally, the third work, E798, which was published in 1849 at the Opera postuma, was probably the first among the three works, to be written by Euler
Entre os diversos recursos metodol?gicos que podem ser trabalhados na sala de aula pelo professor de matem?tica, podemos citar a Hist?ria da Matem?tica que contribui para a elabora??o de atividades que promovam curiosidade hist?rica e matem?tica nos discentes. Assim, a presente disserta??o objetiva traduzir e analisar, matematicamente e historicamente, os tr?s trabalhos de Euler sobre os n?meros amig?veis que foram escritos durante o s?culo XVIII com o mesmo t?tulo: De numeris amicabilibus. Estes trabalhos, apesar de terem sido escritos em 1747 quando Euler vivia em Berlim, eles foram publicados em datas e lugares diferentes. O primeiro, publicado em 1747 na Nova Acta Eruditorum e que recebeu a numera??o E100 do ?ndex Enestr?m, apresenta resumidamente o contexto hist?rico dos n?meros amig?veis, menciona a f?rmula 2nxy & 2nz que foi usada por seus precursores e ainda apresenta uma tabela contendo como resultado trinta pares de n?meros amig?veis. Por sua vez, o segundo trabalho, E152, foi publicado em 1750 na Opuscula varii argumenti, ele ? o resultado de uma an?lise completa da pesquisa de Euler sobre os n?meros amig?veis que resultou em um cat?logo contendo 61 pares, quantidade n?o alcan?ada por nenhum matem?tico antes de Euler. Por fim, o terceiro trabalho, E798, que foi publicado em 1849 na Opera postuma, provavelmente tenha sido o primeiro, entre os tr?s trabalhos, a ser escrito por Euler
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Ungun, Yigit. "Numerical Solution Of One Dimensional Detonation Tube With Reactive Euler Equations Using High Resolution Method." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614128/index.pdf.
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In this thesis, numerical simulation of one dimensional detonation tube problem is solved
with finite rate chemistry. For the numerical simulation, Euler equations have been used.
Since detonation tube phenomena occurs in high speed flows, viscosity eects and gravity
forces are negligible. In this thesis, Godunov type methods have been studied and afterwards
high resolution method is used for the numerical solution of the detonation tube problem. To
solve the chemistry aspect of the problem ZND theory have been used. For the numerical
solution, a FORTRAN code is written and the numerical solution of the problems compared
with the exact ZND solutions.
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Fonte, Carla Cristina 1990. "Introdução aos grafos no ensino médio." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/306327.
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Orientador: Pedro José CatuognoDissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica
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Resumo: Neste trabalho, exploram-se os conceitos iniciais e aplicações importantes da teoria de grafos. Acentuam-se, nas aplicações, alguns problemas clássicos, como o das sete pontes de Königsberg, o do caixeiro viajante e o problema dos casamentos estáveis. Com o intuito de servir como material de apoio para a introdução de grafos ao ensino médio, expõe-se uma sugestão para plano de aula, cuja exploração sinaliza diversas propriedades matemáticas interessantes, além de estimular o raciocínio e o estudo
Abstract: This work focuses on the initial concepts and important applications of the graph theory. Detailing, in the applications, some classic problems such as the seven bridges of Königsberg problem, the travelling salesman problem and the stable marriage problem. In order to provide a supporting material for the introduction to graphs in high school, it is shown a suggestion to the lesson plan, which exploration indicates various interesting mathematical properties beyond stimulating the reasoning and the deep study in the field
Mestrado
Matemática em Rede Nacional
Mestra em Matemática em Rede Nacional
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FREITAS, Janderson dos Santos de. "O Teorema de Euler para poliedros e a topologia dos grafos no ensino básico." Universidade Federal do Maranhão, 2017. http://tedebc.ufma.br:8080/jspui/handle/tede/1873.
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The paper presents problem solving using Graph Theory and Euler’s Theorem. The research performs specific activities in high school involving graphs in various applications of the Euler relation as a problem solving method with Graph Theory. The relationship of Euler is presented in a Geometric view and by the graphs planning. The research proposes a link between the students ’daily problems with the modeling of problem situations by the Graph Theory, specifically the planar graphs solved with the implementation of Euler’ s Theorem focused on the teaching of basic mathematics. Applications of Graph Theory are shown in solving problems with the bridges of the city of Barra do Corda and the students’ school life.
O trabalho apresenta a resolução de problemas utilizando a Teoria dos Grafos e o Teorema de Euler. Uma pesquisa que executa atividades específicas no ensino médio envolvendo grafos em várias aplicações da relação de Euler como método de resolução de problemas com Teoria dos Grafos. A relação de Euler é apresentada em uma visão Geométrica e pela planificação dos grafos. Propondo um elo entre os problemas do cotidiano dos alunos com a modelagem de situações problema pela Teoria dos Grafos, especificamente os grafos planares resolvidos com a implementação do Teorema de Euler voltado ao ensino de matemática básica. São mostradas aplicações da Teoria dos Grafos na resolução de problemas com as pontes da cidade de Barra do Corda e da vida escolar dos alunos.
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Ho, Qhinhon D. "An Assessment Of The Accuracy Of The Euler-Bernoulli Beam Theory For Calculating Strain and Deflection in Composite Sandwich Beams." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2084.
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This study focuses on assessing the accuracy of the Euler-Bernoulli beam theory as computational bases to calculate strain and deflection of composite sandwich beam subjected to three-point and four-point bending. Two groups of composite sandwich beams tests results will be used for comparison purposes. Mechanical properties for the laminated skin are provided by researchers from University of Mississippi (Ellen Lackey et al., 2000). Mechanical properties for the balsa wood core are provided by Alcan Baltek Corporation. Appropriate material properties and test geometries are then used in the Euler-Bernoulli-based algorithm in order to generate analytical data for comparison to experimental data provided by researchers from University of New Orleans (UNO, 2005). The resulting single material cross section is then analyzed in the traditional manner using the Euler-Bernoulli beam theory. In general, the Euler-Bernoulli beam theory provides an appropriate analytical approach in predicting flexural behavior of composite sandwich beams.
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Pratt, Brittan Sheldon. "An assessment of least squares finite element models with applications to problems in heat transfer and solid mechanics." Texas A&M University, 2008. http://hdl.handle.net/1969.1/85941.
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Research is performed to assess the viability of applying the least squares model
to one-dimensional heat transfer and Euler-Bernoulli Beam Theory problems. Least
squares models were developed for both the full and mixed forms of the governing
one-dimensional heat transfer equation along weak form Galerkin models. Both least
squares and weak form Galerkin models were developed for the first order and second
order versions of the Euler-Bernoulli beams.
Several numerical examples were presented for the heat transfer and Euler-
Bernoulli beam theory. The examples for heat transfer included: a differential equation having the same form as the governing equation, heat transfer in a fin, heat
transfer in a bar and axisymmetric heat transfer in a long cylinder. These problems
were solved using both least squares models, and the full form weak form Galerkin
model. With all four examples the weak form Galerkin model and the full form least
squares model produced accurate results for the primary variables. To obtain accurate results with the mixed form least squares model it is necessary to use at least
a quadratic polynominal. The least squares models with the appropriate approximation functions yielde more accurate results for the secondary variables than the weak
form Galerkin.
The examples presented for the beam problem include: a cantilever beam with
linearly varying distributed load along the beam and a point load at the end, a simply
supported beam with a point load in the middle, and a beam fixed on both ends with a distributed load varying cubically. The first two examples were solved using the
least squares model based on the second order equation and a weak form Galerkin
model based on the full form of the equation. The third problem was solved with
the least squares model based on the second order equation. Both the least squares
model and the Galerkin model calculated accurate results for the primary variables,
while the least squares model was more accurate on the secondary variables.
In general, the least-squares finite element models yield more acurate results for
gradients of the solution than the traditional weak form Galkerkin finite element models. Extension of the present assessment to multi-dimensional problems and nonlinear
provelms is awaiting attention.
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Kurmann, André. "New Keynesian price and cost dynamics : theory and evidence /." Full text, Acrobat Reader required, 2002. http://www.gbv.de/dms/zbw/557985994.pdf.
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Lapébie, Julie. "Sur la topologie des ensembles semi-algébriques : caractéristique d'Euler; degré topologique et indice radial." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4719/document.
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Suite aux travaux de Zbigniew Szafraniec et Nicolas Dutertre, je me suis intéressée aux calculs de caractéristiques d'Euler de certains espaces semi-algébriques. En particulier, ceux de laforme : $ {(-1)^{varepsilon_1} G_1geq 0 }cap...cap{(-1)^{varepsilon_l} G_lgeq 0}cap W$, où $epsilon=(epsilon_1,...,epsilon_l)in{0,1}^l$, $G=(G_1,...,G_l):R^nrightarrowR^l$ polynomiale et $W:=F^{-1}(0)subsetR^n$ où $F:R^nrightarrowR^k$ et $k+lleq n$. Une fois le cas lisse traité, on intersecte ces ensembles avec ${ fgeq 0}$ ou ${ fleq 0}$, où $f$ est polynomiale telle que $f^{-1}(0)$ admette un nombre fini de singularités. J'énonce alors un théorème reliant ces caractéristiques au degré d'applications faisant intervenir les fonctions $f$, $F$ et $G$. Pour finir, on s'intéresse au cas où l'ensemble $W$ possède un lieu critique compact.Dans une autre partie, je travaille sur l'indice radial, indice défini sur des variétés singulières. J'énonce un résultat faisant le lien entre l'indice radial d'un champ de vecteurs V en une singularité avec l'indice radial de son opposé -V. Finalement, je relie l'indice radial à un indice d'intersectionAfter the works of Zbigniew Szafraniec and Nicolas Dutertre, we are interested in computing Euler characteristics of some particular semialgebraic sets. In particular, the ones of the form : $ {(-1)^{varepsilon_1} G_1geq 0 }cap...cap{(-1)^{varepsilon_l} G_lgeq 0}cap W$, where $varepsilon=(varepsilon_1,...,varepsilon_l)in{0,1}^l$, $G=(G_1,...,G_l):R^nrightarrowR^l$ polynomial and $W:=F^{-1}(0)subsetR^n$ where $F:R^nrightarrowR^k$ and $k+lleq n$. Once the smooth case is treated, we intersect these sets with ${ fgeq 0}$ or ${ fleq 0}$, where $f$ is polynomial such that $f^{-1}(0)$ contains a finite number of singularities. Then we state a theorem that makes a link between these caracteristics and some degrees of mappings involving the functions $f$, $F$ and $G$. Finally, we study the case where $W$ has a compact singular set.In another part, I work with the radial index, an index defined for singular manifolds. I have a result making a link between the radial index of a vector field V and its opposite -V at a singularity. Finally, I relate that radial index to an intersection index
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Batihan, Ali Cagri. "Vibration Analysis Of Cracked Beams On Elastic Foundation Using Timoshenko Beam Theory." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613602/index.pdf.
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In this thesis, transverse vibration of a cracked beam on an elastic foundation and
the effect of crack and foundation parameters on transverse vibration natural
frequencies are studied. Analytical formulations are derived for a beam with
rectangular cross section. The crack is an open type edge crack placed in the
medium of the beam and it is uniform along the width of the beam. The cracked
beam rests on an elastic foundation. The beam is modeled by two different beam
theories, which are Euler-Bernoulli beam theory and Timoshenko beam theory.
The effect of the crack is considered by representing the crack by rotational
springs. The compliance of the spring that represents the crack is obtained by
using fracture mechanics theories. Different foundation models are discussedthese models are Winkler Foundation, Pasternak Foundation, and generalized foundation. The equations of motion are derived by applying Newton'
s 2nd law on an infinitesimal beam element. Non-dimensional parameters are introduced into equations of motion. The beam is separated into pieces at the crack location. By applying the compatibility conditions at the crack location and boundary conditions, characteristic equation whose roots give the non-dimensional natural frequencies is obtained. Numerical solutions are done for a beam with square cross sectional area. The effects of crack ratio, crack location and foundation parameters on transverse vibration natural frequencies are presented. It is observed that existence of crack reduces the natural frequencies. Also the elastic foundation increases the stiffness of the system thus the natural frequencies. The natural frequencies are also affected by the location of the crack.
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Zugliani, Giuliano Angelo. "Fórmulas de Poincaré-Hopf e classes características de variedades singulares." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-02042008-144834/.
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Neste trabalho, estudamos diferentes construções e propriedades das classes características de variedades suaves e singulares. Para ilustrar a teoria, calculamos a obstrução de Euler de algumas superfícies singulares no espaço tridimensional e apresentamos uma fórmula do tipo Poincaré-Hopf para variedades singularesIn this work, we study different constructions and properties of the characteristics classes of smooth and singular manifolds. To ilustrate the theory, we compute the Euler obstructions of some singular surfaces in tridimensional space and state a Poincaré-Hopf´s formula for singular varieties
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Dantas, Joice de Andrade. "De solutione problematum diophanteorum per n?meros integros : o primeiro trabalho de Euler sobre equa??es diofantinas." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/14500.
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Previous issue date: 2011-11-07The present dissertation analyses Leonhard Euler?s early mathematical work as Diophantine Equations, De solutione problematum diophanteorum per n?meros ?ntegros (On the solution of Diophantine problems in integers). It was published in 1738, although it had been presented to the St Petersburg Academy of Science five years earlier. Euler solves the problem of making the general second degree expression a perfect square, i.e., he seeks the whole number solutions to the equation ax2+bx+c = y2. For this purpose, he shows how to generate new solutions from those already obtained. Accordingly, he makes a succession of substitutions equating terms and eliminating variables until the problem reduces to finding the solution of the Pell Equation. Euler erroneously assigns this type of equation to Pell. He also makes a number of restrictions to the equation ax2+bx+c = y and works on several subthemes, from incomplete equations to polygonal numbers
Nesta pesquisa analisamos historicamente e matematicamente o primeiro trabalho de Leonhard Euler sobre Equa??es Diofantinas o De solutione problematum diophanteorum per n?meros integros ( Sobre a solu??o de problemas diofantinos por n?meros inteiros ). Foi publicado em 1738, embora apresentado ? Academia de S?o Petersburgo cinco anos antes. No texto, Euler trata do problema de fazer com que a express?o generalizada do segundo grau seja igual a um quadrado perfeito, isto ?, procura solu??es no conjunto dos n?meros inteiros para equa??o ax2+bx+c = y2. Para tanto, Euler mostra como descobrir mais solu??es depois que uma primeira ? encontrada, fazendo uma s?rie de substitui??es combinando termos e eliminando vari?veis, at? que o trabalho se resume a encontrar a solu??o para ,q=ⱱap?+1 uma equa??o de Pell. Este trabalho ? o primeiro tamb?m em que Euler atribui erroneamente esse tipo de equa??o a Pell. Euler faz tamb?m, uma s?rie de restri??es para a equa??o ax2+bx+c = y2 e trabalha com diversos subcasos, que v?o desde equa??es incompletas at? o trabalho com n?meros poligonais
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Ruiz, Camila Mariana. "Sobre a topologia das singularidades de Morin." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-12012016-155424/.
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Neste trabalho, nós abordamos alguns resultados de T. Fukuda e de N. Dutertre e T. Fukui sobre a topologia das singularidades de Morin. Em particular, apresentamos uma nova prova para o Teorema de Dutertre-Fukui [2, Theorem 6.2], para o caso em que N = Rn, usando a Teoria de Morse para variedades com bordo. Baseados nas propriedades de um n-campo de vetores gradiente (∇ f1; : : : ∇fn) de uma aplicação de Morin f : M → Rn, com dim M ≥ n, na segunda parte deste trabalho, nós introduzimos o conceito de n-campos de Morin para n-campos de vetores que não são necessariamente gradientes. Nós também generalizamos o resultado de T. Fukuda [3, Theorem 1], que estabelece uma equivalência módulo 2 entre a característica de Euler de uma variedade diferenciável M e a característica de Euler dos conjuntos singulares de uma aplicação de Morin definida sobre M, para o contexto dos n-campos de Morin.In this work, we revisit results of T. Fukuda and N. Dutertre and T. Fukui on the topology of Morin maps. In particular, we give a new proof for Dutertre-Fukui\'s Theorem [2, Theorem 6.2] when N = Rn, using Morse Theory for manifolds with boundary. Based on the properties of a gradient n-vector field (∇ f1; : : : ∇ fn) of a Morin map f : M → Rn, where dim M ≥ n, in the second part of this work, we introduce the concept of Morin n-vector field for n-vector fields V = (V1; : : : ; Vn) that are not necessarily gradients. We also generalize the result of T. Fukuda [3, Theorem 1], which establishes a module 2 equivalence between Euler\'s characteristic of a manifold M and Euler\'s characteristic of the singular sets of a Morin map defined on M, to the context of Morin n-vector fields.
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Dettmann, Aaron. "Loosely coupled, modular framework for linear static aeroelastic analyses." Thesis, KTH, Lättkonstruktioner, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-262047.
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A computational framework for linear static aeroelastic analyses is presented. The overall aeroelasticity model is applicable to conceptual aircraft design studies and other low-fidelity aero-structural analyses. A partitioned approach is used, i. e. separate solvers for aerodynamics and structure analyses are coupled in a suitable way, together forming a model for aeroelastic simulations. Aerodynamics are modelled using the vortexlattice method (VLM), a simple computational fluid dynamics (CFD) model based on potential flow. The structure is represented by a three-dimensional (3D) Euler-Bernoulli beam model in a finite element method (FEM) formulation. A particular focus was put on the modularity and loose coupling of aforementioned models. The core of the aeroelastic framework was abstracted, such that it does not depend on any specific details of the underlying aerodynamics and structure modules. The final aeroelasticity model constitutes independent software tools for the VLM and the beam FEM, as well as a framework enabling the aeroelastic coupling. These different tools have been developed as part of this thesis work. A wind tunnel experiment with a simple wing model is presented as a validation test case. An aero-structural analysis of a fully elastic unmanned aerial vehicle (UAV) (OptiMale) is described and results are compared with an existing higherfidelity study.Rapporten beskriver en beräkningsmodell för linjära, statisk aeroelastiska analyser. Modellen kan användas för konceptuella designstudier av flygplan. En partitionerad metod används, d v s separata lösare för aerodynamik- och strukturanalyser kopplas på ett lämpligt sätt, och bildar tillsammans en modell för aeroelastiska simulationer. Aerodynamik modelleras med hjälp av en så kallad vortex-lattice method (VLM), en enkel modell för beräkningsströmningsdynamik (CFD) som är baserad på friktionsfri strömning. Strukturen representeras av en tredimensionell (3D) Euler-Bernoulli-balkmodell implementerad med hjälp av en finita elementmetod (FEM). Ovannämnda modeller har utvecklats med fokus på modularitet och lös koppling. Kärnan i den aeroelastiska modellen har abstraherats så att den inte beror på specifika detaljer i de underliggande aerodynamik- och strukturmodulerna. Aeroelasticitetsmodellen i sin helhet består av separata mjukvaruprogram för VLM och balk-FEM, såväl som ett ramverk som möjliggör den aeroelastiska kopplingen. Dessa olika program har utvecklats som en del av examensarbetet. Ett vindtunnelförsök med en enkel vingmodell presenteras som ett valideringstest. Dessutom beskrivs en analys av ett elastiskt obemannad flygplan (OptiMale) och resultaten jämförs med en befintlig studie som har genomförts med modeller av högre trovärdighet.
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Cramm, Kenneth Peter. "Solutions to the Chinese Postman Problem." CSUSB ScholarWorks, 2000. https://scholarworks.lib.csusb.edu/etd-project/1683.
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Considering the Chinese Postman Problem, in which a mailman must deliver mail to houses in a neighborhood. The mailman must cover each side of the street that has houses, at least once. The focus of this paper is our attempt to discover the optimal path, or the least number of times each street is walked. The integration of algorithms from graph theory and operations research form the method used to explain solutions to the Chinese Postman Problem.
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Rezende, Ana Claudya Botelho de. "Uma generalização da Circunferência dos Nove Pontos para a Educação Básica." reponame:Repositório Institucional da UFABC, 2017.
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Orientadora: Profa. Dra. Ana Carolina BoeroDissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Mestrado Profissional em Matemática em Rede Nacional, 2017.
Neste trabalho, mostraremos que dado um triângulo e três cevianas que se intersetam em um ponto P, existe uma cônica que passa pelos pontos médios dos lados, pelos pés das cevianas e pelos pontos médios dos segmentos que unem P aos vértices do triângulo. Antes de apresentá-lo, contudo, exploraremos a Reta de Euler, a Circunferência dos Nove Pontos e algumas de suas principais propriedades. Finalizaremos este trabalho com duas sugestões de atividades que permitirão ao aluno construir conceitos matemáticos de maneira informal, intuitiva e lúdica, despertando seu interesse por Geometria e pela Matemática em geral.
In this work, we will show that given a triangle and three cevians that intersect at a point P, there is a conic that passes through the midpoints of the sides, the feet of the cevians and the midpoints of the segments that join P to the vertices of the triangle. Before presenting it, however, we will explore the Euler Line, the Nine-Point Circle and some of its main properties. We will finish this work with two suggestions of activities that will allow the student to construct mathematical concepts in an informal, intuitive and playful way, arousing his interest in Geometry and Mathematics in general.
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Le, goff Nicolas. "Construction of a conformal hexahedral mesh from volume fractions : theory and applications." Electronic Thesis or Diss., université Paris-Saclay, 2020. http://www.theses.fr/2020UPASG033.
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Ces travaux abordent le problème de la génération automatique de maillages hexaédriques pour des codes de simulation, à partir d'un maillage portant des fractions volumiques, c'est-à-dire dont les mailles peuvent contenir plusieurs matériaux. La solution proposée doit contruire un maillage hexaédrique dans lequel chaque maille correspond à un seul matériau, et dont les interfaces entre matériaux doivent former des surfaces lisses. D'un point de vue théorique, nous cherchons à adapter et étendre des solutions existantes, et à les appliquer sur une large variété d'exemples : certains issus de modèles de CAO (plaqués sur un maillage pour obtenir des fractions volumiques), d'autres générés procéduralement et enfin d'autres utilisés dans un rôle d'intercode, récupérés en sortie de codes de simulation. Nous définissons une métrique permettant d'évaluer notre (et d'autres) méthodes, ainsi qu'un post-processus pour améliorer ces résultats; nous introduisons également une méthode de reconstruction d'interfaces discrètes inspirés de méthodes issues du domaine de la visualisation scientifique, et nous proposons un algorithme appelé {sc ELG} avec garantie sur la qualité du maillage, faisant intervenir des modifications géométriques et topologiques sur ce maillageThis thesis addresses the problem of the automatic generation of purely hexahedral meshes for simulation codes when having a mesh carrying volume fraction data as an input, meaning that there can be several materials inside one cell. The proposed approach should create an hexahedral mesh where each cell corresponds to a single material, and where interfaces between materials form smooth surfaces. From a theoretical standpoint, we aim at adapting and extending state-of-the-art techniques and we apply them on examples, some classically issued from CAD models (and imprinted onto a mesh to obtain volume fractions), some procedurally generated cases and others in an intercode capacity where we take the results of a first simulation code to be our inputs. We first define a metric that allows the evaluation of our (or others') results and a method to improve those; we then introduce a discrete material interface reconstruction method inspired from the scientific visualization field and finally we present an algorithmic pipeline, called {sc ELG}, that offers a guarantee on the mesh quality by performing geometrical and topological mesh adaptation
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Kaalen, Stefan. "Semi-Markov processes for calculating the safety of autonomous vehicles." Thesis, KTH, Matematisk statistik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-252331.
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Several manufacturers of road vehicles today are working on developing autonomous vehicles. One subject that is often up for discussion when it comes to integrating autonomous road vehicles into the infrastructure is the safety aspect. There is in the context no common view of how safety should be quantified. As a contribution to this discussion we propose describing each potential hazardous event of a vehicle as a Semi-Markov Process (SMP). A reliability-based method for using the semi-Markov representation to calculate the probability of a hazardous event to occur is presented. The method simplifies the expression for the reliability using the Laplace-Stieltjes transform and calculates the transform of the reliability exactly. Numerical inversion algorithms are then applied to approximate the reliability up to a desired error tolerance. The method is validated using alternative techniques and is thereafter applied to a system for automated steering based on a real example from the industry. A desired evolution of the method is to involve a framework for how to represent each hazardous event as a SMP.Flertalet tillverkare av vägfordon jobbar idag på att utveckla autonoma fordon. Ett ämne ofta på agendan i diskussionen om att integrera autonoma fordon på vägarna är säkerhet. Det finns i sammanhanget ingen klar bild över hur säkerhet ska kvantifieras. Som ett bidrag till denna diskussion föreslås här att beskriva varje potentiellt farlig situation av ett fordon som en Semi-Markov process (SMP). En metod presenteras för att via beräkning av funktionssäkerheten nyttja semi-Markov representationen för att beräkna sannolikheten för att en farlig situation ska uppstå. Metoden nyttjar Laplace-Stieltjes transformen för att förenkla uttrycket för funktionssäkerheten och beräknar transformen av funktionssäkerheten exakt. Numeriska algoritmer för den inversa transformen appliceras sedan för att beräkna funktionssäkerheten upp till en viss feltolerans. Metoden valideras genom alternativa tekniker och appliceras sedan på ett system för autonom styrning baserat på ett riktigt exempel från industrin. En fördelaktig utveckling av metoden som presenteras här skulle vara att involvera ett ramverk för hur varje potentiellt farlig situation ska representeras som en SMP.
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Jacobsson, Mattias. "Bitwise relations between n and φ(n) : A novel approach at prime number factorization." Thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-16655.
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Cryptography plays a crucial role in today’s society. Given the influence, cryptographic algorithms need to be trustworthy. Cryptographic algorithms such as RSA relies on the problem of prime number factorization to provide its confidentiality. Hence finding a way to make it computationally feasible to find the prime factors of any integer would break RSA’s confidentiality. The approach presented in this thesis explores the possibility of trying to construct φ(n) from n. This enables factorization of n into its two prime numbers p and q through the method presented in the original RSA paper. The construction of φ(n) from n is achieved by analyzing bitwise relations between the two. While there are some limitations on p and q this thesis can in favorable circumstances construct about half of the bits in φ(n) from n. Moreover, based on the research a conjecture has been proposed which outlines further characteristics between n and φ(n).
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Garcia, Menendez Fernando. "High-resolution three-dimensional plume modeling with Eulerian atmospheric chemistry and transport models." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50264.
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Eulerian chemical transport models are extensively used to steer environmental policy, forecast air quality and study atmospheric processes. However, the ability of these models to simulate concentrated atmospheric plumes, including fire-related smoke, may be limited. Wildland fires are important sources of air pollutants and can significantly affect air quality. Emissions released in wildfires and prescribed burns have been known to substantially increase the air pollution burden at urban locations across large regions. Air quality forecasts generated with numerical models can provide valuable information to environmental regulators and land managers about the potential impacts of fires. Eulerian models present an attractive framework to simulate the transport and transformation of fire emissions. Still, the limitations inherent to chemical transport models when applied to replicate smoke plumes must be identified and well understood to adequately interpret results and further improve the models' predictive skills. Here, a modeling framework centered on the Community Multiscale Air Quality modeling system (CMAQ) is used to simulate several fire episodes that occurred in the Southeastern U.S. and investigate the sensitivity of fine particulate matter concentration predictions to various model inputs and parameters. Significant sources of uncertainty in the model are identified and discussed, including the spatiotemporal allocation of fire emissions and meteorological drivers. In addition, special attention is given to model grid resolution. Adaptive grid modeling is explored as a strategy to simulate fire-related plumes. An adaptive version of CMAQ, capable of dynamically restructuring the grid on which solution fields are estimated and providing refinement at the regions where accuracy is most dependent on resolution, is presented. The fully adaptive three-dimensional modeling technique can be applied to reach unprecedented levels of grid resolution and provide insight into plume dynamics unattainable with static grid models. Through this work the capability of current chemical transport models to replicate fire-related air quality impacts is evaluated, key research needs to achieve effective simulations are identified, and numerical tools designed to improve model performance are developed.
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Gonzalez, Campos David Jonathan. "A Study of Shock Analysis Using the Finite Element Method Verified with Euler-Bernoulli Beam Theory; Mechanical Effects Due to Pulse Width Variation of Shock Inputs; and Evaluation of Shock Response of a Mixed Flow Fan." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1294.
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A Study Of Shock Analysis Using The Finite Element Method Verified With Euler-Bernoulli Beam Theory; Mechanical Effects Due To Pulse Width Variation Of Shock Inputs; And Evaluation Of Shock Response Of A Mixed Flow Fan
David Jonathan González Campos
For many engineers that use finite element analysis or FEA, it is very important to know how to properly model and obtain accurate solutions for complicated loading conditions such as shock loading. Transient acceleration loads, such as shocks, are not as common as static loads. Analyzing these types of problems is less understood, which is the basis for this study. FEA solutions are verified using classical theory, as well as experimental results. The complex loading combination of shock and high speed rotation is also studied. Ansys and its graphic user interface, Workbench Version 14.5, are the programs used to solve these types of problems. Classical theory and Matlab codes, as well as experimental results, are used to verify finite element solutions for a simple structure, such as a cantilevered beam. The discrepancy of these FEA results is found to be 2.3%. The Full Method and the Mode Superposition Method in Ansys are found to be great solution tools for shock loading conditions, including complex acceleration and force conditions. The Full Method requires less pre-processing but solutions could take days, as opposed to hours, to complete in comparison with the Mode Superposition Method, depending on the 3D Model. The Mode Superposition Method requires more time and input by the user but solves relatively quickly. Furthermore, a new representation of critical pulse width of the shock inputs is presented. Experimental and finite element analyses of a complete mixed flow fan undergoing ballistic shock is also completed; deformation results due to shock loading, combined with rotation and aerodynamic loading, account for 32.3% of the total deformation seen from experimental testing. Solution methods incorporated in Ansys, and validation of FEA results using theory, have great potential implications as powerful tools for engineering students and practicing engineers.
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Dixit, Akash. "Damage modeling and damage detection for structures using a perturbation method." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43575.
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This thesis is about using structural-dynamics based methods to address the existing challenges in the field of Structural Health Monitoring (SHM). Particularly, new structural-dynamics based methods are presented, to model areas of damage, to do damage diagnosis and to estimate and predict the sensitivity of structural vibration properties like natural frequencies to the presence of damage.
Towards these objectives, a general analytical procedure, which yields nth-order expressions governing mode shapes and natural frequencies and for damaged elastic structures such as rods, beams, plates and shells of any shape is presented. Features of the procedure include the following:
1. Rather than modeling the damage as a fictitious elastic element or localized or global change in constitutive properties, it is modeled in a mathematically rigorous manner as a geometric discontinuity.
2. The inertia effect (kinetic energy), which, unlike the stiffness effect (strain energy), of the damage has been neglected by researchers, is included in it.
3. The framework is generic and is applicable to wide variety of engineering structures of different shapes with arbitrary boundary conditions which constitute self adjoint systems and also to a wide variety of damage profiles and even multiple areas of damage.
To illustrate the ability of the procedure to effectively model the damage, it is applied to beams using Euler-Bernoulli and Timoshenko theories and to plates using Kirchhoff's theory, supported on different types of boundary conditions. Analytical results are compared with experiments using piezoelectric actuators and non-contact Laser-Doppler Vibrometer sensors.
Next, the step of damage diagnosis is approached. Damage diagnosis is done using two methodologies. One, the modes and natural frequencies that are determined are used to formulate analytical expressions for a strain energy based damage index. Two, a new damage detection parameter are identified.
Assuming the damaged structure to be a linear system, the response is expressed as the summation of the responses of the corresponding undamaged structure and the response (negative response) of the damage alone. If the second part of the response is isolated, it forms what can be regarded as the damage signature. The damage signature gives a clear indication of the damage. In this thesis, the existence of the damage signature is investigated when the damaged structure is excited at one of its natural frequencies and therefore it is called ``partial mode contribution". The second damage detection method is based on this new physical parameter as determined using the partial mode contribution. The physical reasoning is verified analytically, thereupon it is verified using finite element models and experiments. The limits of damage size that can be determined using the method are also investigated. There is no requirement of having a baseline data with this damage detection method. Since the partial mode contribution is a local parameter, it is thus very sensitive to the presence of damage. The parameter is also shown to be not affected by noise in the detection ambience.
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Jeong, Minsoo. "Asymptotics for the maximum likelihood estimators of diffusion models." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2335.
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Belkhiri, Ayman. "Modélisation dynamique de la locomotion compliante : Application au vol battant bio-inspiré de l'insecte." Phd thesis, Ecole des Mines de Nantes, 2013. http://tel.archives-ouvertes.fr/tel-00874497.
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Le travail présenté dans cette thèse est consacré à la modélisation de la dynamique de locomotion des "soft robots", i.e. les systèmes multi-corps mobiles compliants. Ces compliances peuvent être localisées et considérées comme des liaisons passives du système,ou bien introduites par des flexibilités distribuées le long des corps. La dynamique de ces systèmes est modélisée en adoptant une approche Lagrangienne basée sur les outils mathématiques développés par l'école américaine de mécanique géométrique. Du point de vue algorithmique, le calcul de ces modèles dynamiques s'appuie sur un algorithme récursif et efficace de type Newton-Euler, ici étendu aux robots locomoteurs munis d'organes compliants. Poursuivant des objectifs de commande et de simulation rapide pour la robotique, l'algorithme proposé est capable de résoudre la dynamique externe directe ainsi que la dynamique inverse des couples internes. Afin de mettre en pratique l'ensemble de ces outils de modélisation, nous avons pris le vol battant des insectes comme exemple illustratif. Les équations non-linéaires qui régissent les déformations passives de l'aile sont établies en appliquant deux méthodes différentes. La première consiste à séparer le mouvement de l'aile en une composante rigide dite de "repère flottant" et une composante de déformation. Cette dernière est paramétrée dans le repère flottant par la méthode des modes supposés ici appliquée à l'aile vue comme une poutre d'Euler-Bernoulli soumise à la flexion et à la torsion. Quant à la seconde approche, les mouvements de l'aile n'y sont pas séparés mais directement paramétrés par les transformations finies rigides et absolues d'une poutre Cosserat. Cette approche est dite Galiléenne ou "géométriquement exacte" en raison du fait qu'elle ne requiert aucune approximation en dehors des inévitables discrétisations spatiale et temporelle imposées parla résolution numérique de la dynamique du vol. Dans les deux cas,les forces aérodynamiques sont prises en compte via un modèle analytique simplifié de type Dickinson. Les modèles et algorithmes résultants sont appliqués à la conception d'un simulateur du vol, ainsi qu'à la conception d'un prototype d'aile, dans le contexte du projet coopératif (ANR) EVA.
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Baxant, Radek. "Řešení stability prutových konstrukcí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227507.
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This diploma thesis deals with the subject of slenderness bars’ stability assessment, especially in the steel structures. Before the assessment of bars in the frame constructions, we search for the influence of the computational model’s settings on the final result. The initial geometrical imperfections are examined on the model of Euler’s bar. The influence of the rigidity of girders on the poles’ buckling length is examined on the basic frame construction. The buckling lengths are assessed in the comparison with the figures we got from the statistical tables and the computational software. The influence of construction’s initial tilt and its replacement by the system of outer forces is examined on the frame structure. Three-hinged frame structure with variable cross-section member is designed then and the influence of non-linear calculations on the inner forces is studied. In the complex frame assessment, the influence of the number of parts of variable cross-section member on the bars’ buckling length is examined.
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Dona, Marco. "Static and dynamic analysis of multi-cracked beams with local and non-local elasticity." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/14893.
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The thesis presents a novel computational method for analysing the static and dynamic behaviour of a multi-damaged beam using local and non-local elasticity theories. Most of the lumped damage beam models proposed to date are based on slender beam theory in classical (local) elasticity and are limited by inaccuracies caused by the implicit assumption of the Euler-Bernoulli beam model and by the spring model itself, which simplifies the real beam behaviour around the crack. In addition, size effects and material heterogeneity cannot be taken into account using the classical elasticity theory due to the absence of any microstructural parameter. The proposed work is based on the inhomogeneous Euler-Bernoulli beam theory in which a Dirac's delta function is added to the bending flexibility at the position of each crack: that is, the severer the damage, the larger is the resulting impulsive term. The crack is assumed to be always open, resulting in a linear system (i.e. nonlinear phenomena associated with breathing cracks are not considered). In order to provide an accurate representation of the structure's behaviour, a new multi-cracked beam element including shear effects and rotatory inertia is developed using the flexibility approach for the concentrated damage. The resulting stiffness matrix and load vector terms are evaluated by the unit-displacement method, employing the closed-form solutions for the multi-cracked beam problem. The same deformed shapes are used to derive the consistent mass matrix, also including the rotatory inertia terms. The two-node multi-damaged beam model has been validated through comparison of the results of static and dynamic analyses for two numerical examples against those provided by a commercial finite element code. The proposed model is shown to improve the computational efficiency as well as the accuracy, thanks to the inclusion of both shear deformations and rotatory inertia. The inaccuracy of the spring model, where for example for a rotational spring a finite jump appears on the rotations' profile, has been tackled by the enrichment of the elastic constitutive law with higher order stress and strain gradients. In particular, a new phenomenological approach based upon a convenient form of non-local elasticity beam theory has been presented. This hybrid non-local beam model is able to take into account the distortion on the stress/strain field around the crack as well as to include the microstructure of the material, without introducing any additional crack related parameters. The Laplace's transform method applied to the differential equation of the problem allowed deriving the static closed-form solution for the multi-cracked Euler-Bernoulli beams with hybrid non-local elasticity. The dynamic analysis has been performed using a new computational meshless method, where the equation of motions are discretised by a Galerkin-type approximation, with convenient shape functions able to ensure the same grade of approximation as the beam element for the classical elasticity. The importance of the inclusion of microstructural parameters is addressed and their effects are quantified also in comparison with those obtained using the classical elasticity theory.
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Chidurala, Manohar. "Dynamic Characteristics of Biologically Inspired Hair Receptors for Unmanned Aerial Vehicles." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2040.
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The highly optimized performance of nature’s creations and biological assemblies has inspired the development of their engineered counter parts that can potentially outperform conventional systems. In particular, bat wings are populated with air flow hair receptors which feedback the information about airflow over their surfaces for enhanced stability and maneuverability during their flight. The hairs in the bat wing membrane play a role in the maneuverability tasks, especially during low-speed flight. The developments of artificial hair sensors (AHS) are inspired by biological hair cells in aerodynamic feedback control designs. Current mathematical models for hair receptors are limited by strict simplifying assumptions of creeping flow hair Reynolds number on AHS fluid-structure interaction (FSI), which may be violated for hair structures integrated on small-scaled Unmanned Aerial Vehicles (UAVs). This study motivates by an outstanding need to understand the dynamic response of hair receptors in flow regimes relevant to bat-scaled UAVs. The dynamic response of the hair receptor within the creeping flow environment is investigated at distinct freestream velocities to extend the applicability of AHS to a wider range of low Reynolds number platforms. Therefore, a threedimensional FSI model coupled with a finite element model using the computational fluid dynamics (CFD) is developed for a hair-structure and multiple hair-structures in the airflow. The Navier-Stokes equations including continuity equation are solved numerically for the CFD model. The grid independence of the FSI solution is studied from the simulations of the hairstructure mesh and flow mesh around the hair sensor. To describe the dynamic response of the hair receptors, the natural frequencies and mode shapes of the hair receptors, computed from the finite element model, are compared with the excitation frequencies in vacuum. This model is described with both the boundary layer effects and effects of inertial forces due to fluid-structure xiv interaction of the hair receptors. For supporting the FSI model, the dynamic response of the hair receptor is also validated considering the Euler-Bernoulli beam theory including the steady and unsteady airflow.
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Stevens, Ben. "Short-time structural stability of compressible vortex sheets with surface tension." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:378713da-cd05-4b9a-856d-bee2b0fb47ce.
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The main purpose of this work is to prove short-time structural stability of compressible vortex sheets with surface tension. The main result can be summarised as follows. Assume we start with an initial vortex-sheet configuration which consists of two inviscid fluids with density bounded below flowing smoothly past each other, where a strictly positive fixed coefficient of surface tension produces a surface tension force across the common interface, balanced by the pressure jump. We assume the fluids are modelled by the compressible Euler equations in three space dimensions with a very general equation of state relating the pressure, entropy and density in each fluid such that the sound speed is positive. Then, for a short time, which may depend on the initial configuration, there exists a unique solution of the equations with the same structure, that is, two fluids with density bounded below flowing smoothly past each other, where the surface tension force across the common interface balances the pressure jump. The mathematical approach consists of introducing a carefully chosen artificial viscosity-type regularisation which allows one to linearise the system so as to obtain a collection of transport equations for the entropy, pressure and curl together with a parabolic-type equation for the velocity. We prove a high order energy estimate for the non-linear equations that is independent of the artificial viscosity parameter which allows us to send it to zero. This approach loosely follows that introduced by Shkoller et al in the setting of a compressible liquid-vacuum interface. Although already considered by Shkoller et al, we also make some brief comments on the case of a compressible liquid-vacuum interface, which is obtained from the vortex sheets problem by replacing one of the fluids by vacuum, where it is possible to obtain a structural stability result even without surface tension.
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Baradat, Aymeric. "Transport optimal incompressible : dépendance aux données et régularisation entropique." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX016/document.
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Cette thèse porte sur le problème de transport optimal incompressible, un problème introduit par Brenier à la fin des années 80 dans le but de décrire l’évolution d’un fluide incompressible et non-visqueux de façon lagrangienne, ou autrement dit en fixant l’état initial et l’état final de ce fluide, et en minimisant une certaine fonctionnelle sur un ensemble de dynamiques admissibles. Ce manuscrit contient deux parties.Dans la première, on étudie la dépendance du problème de transport optimal incompressible par rapport aux données. Plus précisément, on étudie la dépendance du champ de pression (le multiplicateur de Lagrange associé à la contrainte d’incompressibilité) par rapport à la mesure γ prescrivant l’état initial et l’état final du fluide. On montre au Chapitre 2 par des méthodes variationnelles que le gradient de la pression, en tant qu’élément d’un espace proche du dual des fonctions C^1, dépend de γ de façon hölderienne pour la distance de Monge-Kantorovic. En contrepartie, on montre au Chapitre 4 que pour tout r > 1, le champ de pression dans l'espace de Lebesgue L^r_t L^1_x ne peut pas être une fonction lipschitzienne de γ. Ce résultat est lié au caractère mal-posé de l’équation d’Euler cinétique, une équation cinétique s’interprétant comme l’équation d’optimalité dans le problème de transport optimal incompressible, à laquelle le Chapitre 3 de cette thèse est dédié.Dans une seconde partie, on s’intéresse à la régularisation entropique du problème de transport optimal incompressible, introduit par Arnaudon, Cruzeiro, Léonard et Zambrini en 2017 sous le nom de problème de Brödinger. On prouve au Chapitre 5 que comme dans le cas du transport optimal incompressible, on peut associer à toute solution un champ scalaire de pression agissant comme multiplicateur de Lagrange pour la contrainte d’incompressibilité. On montre ensuite au Chapitre 6 que lorsque le paramètre de régularisation tend vers zéro, le problème de Brödinger converge vers le problème de transport optimal incompressible au sens de la Γ-convergence, et avec convergence des champs de pression. Ce dernier chapitre est issu d'un travail effectué en collaboration avec L. MonsaingeonThis thesis focuses on Incompressible Optimal Transport, a minimization problem introduced by Brenier in the late 80's, aiming at describing the evolution of an incompressible and inviscid fluid in a Lagrangian way , i.e. by prescribing the state of the fluid at the initial and final times and by minimizing some functional among the set of admissible dynamics. This text is divided into two parts.In the first part, we study the dependence of this optimization problem with respect to the data. More precisely, we analyse the dependence of the pressure field, the Lagrange multiplier corresponding to the incompressibility constraint, with respect to the endpoint conditions, described by a probability measure γ determining the state of the fluid at the initial and final times. We show in Chapter 2 by purely variational methods that the gradient of the pressure field, as an element of a space that is close to the dual of C^1, is a Hölder continuous function of γ for the Monge-Kantorovic distance. On the other hand, we prove in Chapter 4 that for all r>1 the pressure field, as an element of L^r_t L^1_x, cannot be a Lipschitz continuous function of γ for the Monge-Kantorovic distance. This last statement is linked to an ill-posedness result proved in Chapter 3 for the so-called kinetic Euler equation, a kinetic PDE interpreted as the optimality equation of the Incompressible Optimal Transport problem.In the second part, we are interested in the entropic regularization of the Incompressible Optimal Transport problem: the so-called Brödinger problem, introduced by Arnaudon, Cruzeiro, Léonard and Zambrini in 2017. On the one hand, we prove in Chapter 5 that similarly to what happens in the Incompressible Optimal Transport case, to a solution always corresponds a scalar pressure field acting as the Lagrange multiplier for the incompressibility constraint. On the other hand, we prove in Chapter 6 that when the diffusivity coefficient tends to zero, the Brödinger problem converges towards the Incompressible Optimal Transport problem in the sense of Gamma-convergence, and with convergence of the pressure fields. The results of Chapter 6 come from a joint work with L. Monsaingeon
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Mazigh, Youness. "Unités de Stark et théorie d'Iwasawa." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCD005/document.
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Dans cette thèse, on construit des systèmes d’Euler à partir des unités (conjecturales) de Stark et celles de Rubin-Stark d’un corps de nombres K, pour décrire l’idéal caractéristique du X-quotient du module d’Iwasawa standard X∞ pour certains caractères p-adiques irréductibles X. Ici X∞ est le groupe de Galois de la pro-p-extension abélienne non ramifiée maximale de K∞, où K∞ est une Zp-extension adéquate de K. Plus précisément, on démontre des résultats de divisibilité formulée par la conjecture principale de la théorie d’Iwasawa. Nos démonstrations reposent essentiellement sur la théorie des systèmes d’EulerIn this thesis, we construct Euler systems coming from the (conjectural) Stark units and those of Rubin-Stark of a number field K, to describe the characteristic ideal of the X-quotient of the standard Iwasawa module X∞, for some p-adic irreducible characters X. Here X∞ is the Galois group of the maximal unramified abelian pro-p-extension of K∞, where K∞ is an adequate Zp-extension of K. Precisely, we demonstrate a divisibility results formulated by the main conjecture of Iwasawa theory. Our demonstrations essentially are based on the theory of Euler systems
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Li, Iila Jingjiao. "Flexible polyhedra : exploring finite mechanisms of triangulated polyhedra." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/271806.
Full textAbstract:
In a quest to design novel deployable structures, flexible polyhedra provide interesting insights. This work follows the discovery of flexible polyhedra and aims to make flexible polyhedra more useful. The dissertation describes how flexible polyhedra can be made. The flexible polyhedra first considered in this dissertation have a rotational degree of freedom. The range of this rotational movement is measured and maximised in this work by numerical maximisation. All polyhedra are established computationally: an iterative solution method is used to find vertex coordinates; several clash detecting methods are described to define whether each rotational position of a flexible polyhedron is physically possible; then a range of motion is defined between occurrences of clashes at the two ends; finally, an optimisation tool is used to maximise the range of motion. By using these tools, the range of motion of two types of simplest flexible polyhedra are maximised. The first type is a series of flexible polyhedra generalised from the Steffen flexible polyhedron. The range of motion of this type is improved to double that of Steffen’s original, from 27° to 59°. Another type of flexible polyhedron is expanded from a model provided by Tachi. Based on the understanding of Steffen’s flexible polyhedron, optimisation parameters are carefully given. This new type has achieved a wider range of motion, so now the range of motion of flexible polyhedron is tripled to 80°. After enlarging the range of motion of the degree of freedom in the 1-dof systems, the dissertation found multiple degrees of freedom in one polyhedron. The multiple mechanisms can be even repetitive, so that an n-dof polyhedron is found. A polyhedron of two degrees of freedom is first presented. Then, a unit cell for any number of mechanisms is found. As a repetitive structure, a 3-dof polyhedron is presented. Finally, this work presents the possibility of configuring a flexible polyhedral torus and a closed polyhedral surface that is able to flex without the need to stop.