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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

[en] ERGODICITY AND ROBUST TRANSITIVITY ON THE REAL LINE / [pt] TRANSITIVIDADE ROBUSTA E ERGODICIDADE DE APLICAÇÕES NA RETA

MIGUEL ADRIANO KOILLER SCHNOOR 08 April 2008 (has links)
[pt] Em meados do século XIX, G. Boole mostrou que a transformação x -> x − 1/x, definida em R − {0}, preserva a medida de Lebesgue (Ble). Mais de um século depois, R. Adler e B.Weiss mostraram que essa aplicação, chamada de transformação de Boole, é, de fato, ergódica com respeito à medida de Lebesgue (Adl). Nesse trabalho, apresentaremos o conceito de sistemas alternantes, definido recentemente por S. Muñoz (Mun), que consiste numa grande classe de aplicações na reta que generaliza a transformação de Boole e que torna possível uma análise abrangente de propriedades como transitividade robusta e ergodicidade. Para mostrar que, sob certas condições, sistemas alternantes são ergódicos com relação à medida de Lebesgue, mostraremos, usando o Teorema do Folclore, que a transformação induzida do sistema alternante é ergódica. / [en] In the middle of the 19th century, G. Boole proved that the transformation x -> x − 1/x, defined on R − {0}, is a Lebesgue measure preserving transformation (Ble). Over one hundred years later, R. Adler and B.Weiss proved that this map, called Boole`s map, is, in fact, ergodic with respect to the Lebesgue measure (Adl). In this work, we present the notion of alternating systems, recently introduced by S. Mu`noz (Mun), which is a large class of functions on the real line that generalizes the Boole`s map and allows us to make a wide analysis on certain properties such as robust transitivity and ergodicity. In order to show that, under certain conditions, alternating systems are ergodic with respect to the Lebesgue measure, we show, using the Folklore Theorem, that the induced transformation of an alternating system is ergodic.
32

Um estudo sobre as origens da L?gica Matem?itca

Sousa, Giselle Costa de 13 June 2008 (has links)
Made available in DSpace on 2014-12-17T14:35:50Z (GMT). No. of bitstreams: 1 GiselleCS_tese.pdf: 1424263 bytes, checksum: 0a3b291c39e9d1dfd7f82f5c1ef897a3 (MD5) Previous issue date: 2008-06-13 / The present study has as objective to explaining about the origins of the mathematical logic. This has its beginning attributed to the autodidactic English mathematician George Boole (1815-1864), especially because his books The Mathematical Analysis of Logic (1847) and An Investigation of the Laws of Thought (1854) are recognized as the inaugural works of the referred branch. However, surprisingly, in the same time another mathematician called Augutus of Morgan (1806-1871) it also published a book, entitled Formal Logic (1847), in defense of the mathematic logic. Even so, times later on this same century, another work named Elements of Logic (1875) it appeared evidencing the Aristotelian logic with Richard Whately (1787-1863), considered the better Aristotelian logical of that time. This way, our research, permeated by the history of the mathematics, it intends to study the logic produced by these submerged personages in the golden age of the mathematics (19th century) to we compare the valid systems in referred period and we clarify the origins of the mathematical logic. For that we looked for to delineate the panorama historical wrapper of this study. We described, shortly, biographical considerations about these three representatives of the logic of the 19th century formed an alliance with the exhibition of their point of view as for the logic to the light of the works mentioned above. In this sense, we aspirated to present considerations about what effective Aristotelian?s logic existed in the period of Boole and De Morgan comparing it with the new emerging logic (the mathematical logic). Besides of this, before the textual analysis of the works mentioned above, we still looked for to confront the systems of Boole and De Morgan for we arrive to the reason because the Boole?s system was considered better and more efficient. Separate of this preponderance we longed to study the flaws verified in the logical system of Boole front to their contemporaries' production, verifying, for example, if they repeated or not. We concluded that the origins of the mathematical logic is in the works of logic of George Boole, because, in them, has the presentation of a new logic, matematizada for the laws of the thought similar to the one of the arithmetic, while De Morgan, in your work, expand the Aristotelian logic, but it was still arrested to her / O presente estudo tem como objetivo uma elucida??o das origens da l?gica matem?tica. Esta tem seu in?cio atribu?do ao matem?tico ingl?s autodidata George Boole (1815-1864), especialmente porque seus livros The Mathematical Analysis of Logic (1847) e An Investigation of the Laws of Thought (1854) s?o reconhecidos como as obras inaugurais do referido ramo. Contudo, curiosamente, na mesma ?poca um outro matem?tico chamado Augutus de Morgan (1806-1871) tamb?m lan?ou um livro, intitulado Formal Logic (1847), em defesa da matematiza??o da l?gica. Mesmo assim, tempos depois neste mesmo s?culo, uma outra obra nomeada Elements of Logic (1875) surgiu evidenciando a l?gica aristot?lica a partir da figura de Richard Whately (1787-1863), considerado o maior l?gico aristot?lico da ?poca. Desta forma, nossa pesquisa, permeada pela hist?ria da matem?tica, prop?e estudar a l?gica produzida por estes personagens imersos na idade ?urea da matem?tica (s?culo XIX) a fim de compararmos os sistemas vigentes no referido per?odo e clarificarmos as origens da l?gica matem?tica. Para isso buscamos delinear o panorama hist?rico envolt?rio deste estudo. Descrevemos, brevemente, considera??es biogr?ficas destes tr?s representantes da l?gica do s?culo XIX aliadas ? exposi??o de seus pontos de vista quanto ? l?gica ? luz das obras citadas acima. Neste sentido, aspiramos ainda apresentar considera??es acerca do que existia de l?gica aristot?lica vigente no per?odo de Boole e De Morgan comparando-a com a nova l?gica emergente (a l?gica matem?tica). Al?m disso, diante da an?lise textual das obras citadas acima, buscamos ainda confrontar os sistemas de Boole e De Morgan a fim de chegarmos ao motivo pelo o qual o de Boole ter sido considerado melhor e mais eficiente. ? parte desta preponder?ncia, almejamos estudar as falhas constatadas no sistema l?gico de Boole frente ? produ??o de seus contempor?neos, verificando, por exemplo, se elas se repetiram ou n?o. Conclu?mos que as origens da l?gica matem?tica residem nas obras de l?gica de George Boole, visto que, nelas, h? a apresenta??o de uma nova l?gica, matematizada pelas leis do pensamento an?logas ?s da aritm?tica, enquanto De Morgan conseguiu em seu trabalho expandir a l?gica aristot?lica, mas ainda esteve preso a ela
33

Calculadora das classes residuais

Gusmai, Daniel Martins January 2018 (has links)
Orientador: Prof. Dr. Eduardo Guéron / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Mestrado Profissional em Matemática em Rede Nacional - PROFMAT, Santo André, 2018. / Calculadoras são aparelhos comuns no cotidiano do homem moderno, contudo, os conceitos matemáticos envolvidos em sua concepção ainda são conhecidos por poucos. Durante séculos, a obstinação da humanidade em construir máquinas capazes de computar de forma autônoma resultou tanto no surgimento dos atuais computadores, como também em um magnífico legado de conhecimentos matemáticos agregados a tal conquista. Conteúdos tais como congruências e álgebra booleana suscitaram a revolução dos sistemas informatizados e tem sido amplamente explorados por meio de inúmeras aplicações, nossa trajetória perpassou pela aritmética modular, o teorema de Euler-Fermat e as classes residuais, além de bases numéricas, tópicos de eletrônica digital e funções booleanas, com foco no desenvolvimento de circuitos lógicos e o engendrar de componentes eletrônicos, que configuram a base para idealização e construção de calculadoras que efetuem as operações aritméticas em bases arbitrárias, objetivo preponderante deste trabalho. O esmiuçar das etapas de construção das calculadoras, viabiliza o aprofundamento dos conceitos matemáticos que a fomentaram. A abordagem dos temas supracitados culmina para aprimorar e evidenciar a aplicabilidade da matemática à essência da era moderna. / Calculators are common apparatuses in the everyday of modern man, however, the mathematical concepts involved in its conception are still known by few. For centuries, mankind¿s obstinacy in building machines capable of computing autonomously resulted in both the emergence of current computers and a magnificent legacy of mathematical knowledge added to such achievement. Contents such as congruences and Boolean algebra have aroused the revolution of computerized systems and it has been extensively explored through numerous applications, our trajectory ran through modular arithmetic, Euler-Fermat¿s theorem and residual classes, as well as numerical bases, topics of digital electronics and Boolean functions, focusing on the development of logic circuits and the generation of electronic components, which form the basis for the design and construction of calculators that perform arithmetic operations on arbitrary bases, a preponderant objective of this work. The to detail of the construction steps of the calculators, enables the deepening of the mathematical concepts that fomented it. The approach to the aforementioned themes culminates in improving and evidencing the applicability of mathematics to the essence of the modern era.
34

Synthèse et décomposition technologique sur réseaux programmables et ASICs

Bosco, Gilles 16 December 1996 (has links) (PDF)
Cette thèse s'intéresse d'une part au problème de décomposition technologique orienté surface sur des réseaux programmables de type FPGAs (Field Programmable Gate Arrays) et d'autre part à la synthèse des macro-générateurs sur ASICs et plus précisément de la synthèse des additionneurs. La décomposition s'articule autour de deux axes essentiels: tout d'abord, il s'agit d'optimiser la taille de la représentation des fonctions booléennes. Les représentations de base choisies ici sont les ROBDDs (Reduced Ordered Binary Decision Diagrams) ainsi qu'une structure dérivée, les ITE (If Then Else). La deuxième étape concerne la décomposition proprement dite. Les technologies cibles sont ici des FPGAs à base de LUT-k (Look Up Table), en particulier les FPGAs XC5200 de Xilinx et Orca de AT&T. Les deux méthodes de décomposition technologique orienté surface proposées permettent une décomposition hétérogène en prenant en compte non pas une seule configuration mais un ensemble de configurations possibles de la cellule cible. La première méthode est fondée sur un parcours descendant et optimisé du ROBDD. La seconde méthode s'appuie sur une modélisation en recouvrement d'hypergraphe du problème de décomposition technologique. Dans les deux méthodes, le coût exact en terme de surface finale du circuit est pris en compte à chaque étape de la décomposition. L'étude menée dans la deuxième partie de la thèse sur la macro-génération conduit dans un premier temps à l'exploration de l'espace des solutions possibles puis à l'optimisation d'une solution sélectionnée par un algorithme de dérivation discrète. L'utilisation d'un filtre permet la restriction de l'espace des solutions à explorer et d'autre part guide le processus de dérivation en éliminant les solutions trivialement médiocres. La combinaison des processus d'exploration et de dérivations permet la génération de macros dont les caractéristiques physiques sont les plus proches possibles de celles fixées par un utilisateur potentiel. Ces méthodes ont été intégrées au sein d'un outil universitaire ASYL+ développé au laboratoire CSI
35

As origens da teoria dos invariantes na Inglaterra e o Mécanique Analytique de Lagrange (1788)

Santos, Nilson Diego de Alcantara [UNESP] 25 February 2014 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-02-25Bitstream added on 2014-06-13T19:52:43Z : No. of bitstreams: 1 000755405.pdf: 721229 bytes, checksum: a665c9ee190d3a2675b924dd4bb2c525 (MD5) / As origens da Teoria dos Invariantes na Inglaterra e o Mécanique Analytique de Lagrange (1788), é um trabalho voltado principalmente a entender uma possível influência que levou George Boole em 1841, a escrever o artigo Exposition of a General Theory of Linear Transformations e verificar se a motivação que o fez produzir este trabalho é igual ou diferente da motivação que ele exerceu sobre Arthur Cayley e consequentemente sobre James Joseph Sylvester. O presente trabalho apresenta um estudo das origens da Teoria dos Invariantes, no século XIX na Inglaterra. De acordo com os historiadores da Matemática o marco do início desta Teoria foi a publicação de George Boole em 1841. Assumimos este artigo como referência principal para realizar nossa pesquisa. Analisamos “antes” e “após” esta publicação de 1841. Concluímos que o Mécanique Analytique de Lagrange, foi a principal motivação para George Boole escrever seu trabalho e, certamente, George Boole foi uma grande influência para Arthur Cayley no que condiz com a escolha do assunto “invariantes” bem como o desenvolvimento desta Teoria por Cayley / The origins of the theory of invariants in England and Mécanique Analytique of Lagrange (1788), is a work geared primarily to understand a possible influence that led George Boole in 1841, writing the article Exposition of the General Theory of Linear Transformations and verify that the motivation that did produce this work is equal or different of the motivation that he exerted on Arthur Cayley and James Joseph Sylvester consequently. This paper presents a study of the Invariant Theory origins, in the nineteenth century in England. According to historians of Mathematics the beginning of this Theory was the publication in 1841 of George Boole. We have taken this article as a reference to our research. We have proposed to analyzed before and after this publication, 1841. We conclude that the Mécanique Analytique Lagrange, was the essential motivation for George Boole write his work, and certainly George Boole was a great influence to Arthur Cayley in which matches the choice of subject invariants as well as the development of this Theory by Cayley
36

Systems biology approaches to somatic cell reprogramming reveal new insights into the order of events, transcriptional and epigenetic control of the process

Scharp, Till 03 November 2014 (has links)
Die Reprogrammierung somatischer Zellen hat sich kürlich als leistungsfähige Technik für die Herstellung von induzierten pluripotenten Stammzellen (iPS Zellen) aus terminal differenzierten Zellen bewährt. Trotz der großen Hoffnung, die sie speziell im Bezug auf patientenspezifische Stammzelltherapie darstellt, gibt es viele Hindernisse auf dem Weg zur Anwendung in der Humanmedizin, die sich von niedrigen Effizienzen bei der technischen Umsetzung bis hin zur unerwünschten Integration von Onkogenen in das menschliche Genom erstrecken. Aus diesem Grund ist es unabdingbar, unser Verständnis der zugrundeliegenden Prozesse und Mechanismen zu vertiefen. Durch neue Datengewinnungsmethoden und stetig wachsende biologische Komplexität hat sich der Denkansatz der Systembiologie in den letzten Jahrzehnten stark etabliert und erfährt eine fortwährende Entwicklung seiner Anwendbarkeit auf komplexe biologische und biochemische Zusammenhänge. Verschiedene mathematische Modellierungsmethoden werden auf den Reprogrammierungsprozess angewendet um Engpässe und mögliche Effizienz-Optimierungen zu erforschen. Es werden topologische Merkmale eines Pluripotenznetzwerkes untersucht, um Unterschiede zu zufällig generierten Netzen und so topologische Einschränkungen des biologisch relevanten Netzwerkes zu finden. Die Optimierung eines Booleschen Modells aus einem selbst kuratierten Netzwerk in Bezug auf Genexpressionsdaten aus Reprogrammierungsexperimenten gewährt tiefgreifende Einblicke in die ersten Schritte und wichtigsten Faktoren des Prozesses. Der Transkriptionsfaktor SP1 spielt hierbei eine wichtige Rolle zur Induktion eines intermediären, transkriptionell inaktiven Zustands. Ein probabilistisches Boole''sches Modell verdeutlicht das Zusammenspiel epigenetischer und transkriptioneller Kontrollprozesse zusammen, um Pluripotenz- und Zelllinien-Entscheidungen in Reprogrammierung und Differenzierung zu treffen. Erklärungen für die geringe Effizienz werden versucht. / Somatic Cell Reprogramming has emerged as a powerful technique for the generation of induced pluripotent stem cells (iPSCs) from terminally differentiated cells in recent years. Although holding great promises for future clinical development, especially in patient specific stem cell therapy, the barriers on the way to a human application are manifold ranging from low technical efficiencies to undesirable integration of oncogenes into the genome. It is thus indispensable to further our understanding of the underlying processes involved in this technique. With the advent of new data acquisition technologies and an ever-growing complexity of biological knowledge, the Systems Biology approach has seen an evolution of its applicability to the elaborate questions and problems of researchers. Using different mathematical modeling approaches the process of somatic cell reprogramming is examined to find out bottlenecks and possible enhancements of its efficiency. I analyze the topological characteristics of a pluripotency network in order to find differences to randomly generated networks and thus deduce constraints of the biologically relevant network. The optimization of a Boolean model from a curated network against early reprogramming gene expression profiles reveals profound insights into the first steps and most important factors of the process. The transcription factor SP1 emerges to play an important role in the induction of an intermediate, transcriptionally inactive state. A probabilistic Boolean network (PBN) illustrates the interplay of transcriptional and epigenetic regulatory processes in order to explain pluripotency and cell lineage decisions in reprogramming and differentiation. Explanations for the low reprogramming efficiencies are tried.

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