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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.
241

Grammaires de graphes et langages formels / Graph grammars and formal languages

Dinh, Trong Hiêu 11 July 2011 (has links)
Cette thèse apporte plusieurs contributions dans le domaine des langages formels. Notre premier travail a été de montrer la pertinence des grammaires de graphes comme outil de démonstration de résultats fondamentaux sur les langages algébriques. Nous avons ainsi reformulé avec un point de vue géométrique les démonstrations du lemme des paires itérantes et du lemme de Parikh. Nous avons ensuite étendu aux graphes réguliers des algorithmes de base sur les graphes finis, notamment pour calculer des problèmes de plus court chemin. Ces extensions ont été faites par calcul de plus petits points fixes sur les grammaires de graphes. Enfin, nous avons caractérisé des familles générales de systèmes de récriture de mots dont la dérivation préserve la régularité ou l’algébricité. Ces familles ont été obtenues par décomposition de la dérivation en une substitution régulière suivie de la dérivation du système de Dyck / Pas de résumé en anglais
242

A construção de significados dos números irracionais no ensino básico: uma proposta de abordagem envolvendo os eixos constituintes dos números reais / The Construction of Irrational Numbers Meaning on Basic School: And approach proposal involving Real Numbers Axes constituents

Pommer, Wagner Marcelo 09 August 2012 (has links)
Considerando-se como fonte primária os manuais escolares brasileiros de Matemática, o saber a ser ensinado ainda situa uma apresentação dual, polarizado no viés pragmático ou teórico, ao que se segue um procedimento temático padrão que privilegia o desenvolvimento operatório envolvendo contextos exatos, finitos e determinísticos. Em particular, essas características se acentuam gravemente no momento de introdução dos números irracionais no ensino básico, o que ocasiona uma abordagem restritiva. Para superar este quadro, Bruner (1987) fundamenta que não devemos adiar o ensino de assuntos essenciais com base na crença de que são difíceis demais, pois as ideias fundamentais de qualquer assunto podem ser ensinadas na escolaridade básica, porém demanda um trabalho para além dos aspectos técnicos, o que equivale a retomada de características ligadas à compreensão. Neste trabalho, tivemos por hipótese que os pares discreto/contínuo; exato/aproximado; finito/infinito, presentes na análise da evolução epistemológica dos números reais e descritos em Machado (2009), se constituem em pilares conceituais essenciais para fundamentar um panorama favorável a uma abordagem significativa do tema dos números irracionais, de modo a compor um amálgama entre os aspectos técnicos e semânticos. Em face da necessária reflexão, em nível educacional, em torno de tal tema, delimitamos inicialmente um contexto investigativo pautado em um estudo qualitativo orientado pela questão Como são abordados os números irracionais no ensino básico, considerando-se como fonte o livro didático de Matemática?, a fim de mapear a apresentação deste assunto no Ensino Fundamental II e no Ensino Médio. O fundamento metodológico se inspirou nos núcleos de significação, descritos em Aguiar&Ozella (2006), que buscou apreender os sentidos que constituem o conteúdo do discurso expresso nos textos dos livros didáticos. O percurso dos núcleos de significação confirmou que, nos livros didáticos analisados, a apresentação dos números irracionais ocorre de modo polarizado: alguns optam por um viés empírico e outros pela definição formal. Verificou-se que, após uma abordagem inicial, não ocorre intercâmbio destas opções, o que acarreta um rápido esgotamento das ferramentas para se desenvolver as temáticas, limitando a compreensão da complexidade dos números irracionais no ensino básico. A partir das hipóteses e da pesquisa empírica, nos propusemos a delinear as contribuições presentes no movimento dialético entre os pares discreto/contínuo, finito/infinito e exato/aproximado, cujas mútuas conexões permeiam um espaço de significações, um campo que possibilita organizar, tecer e ampliar a rede de significados, conforme Machado (1995), favorecendo um quadro de maior compreensão à apresentação dos números irracionais. O enfoque epistemológico realizado revelou uma multiplicidade de relações envolvendo os números irracionais e diversos assuntos do currículo de Matemática, não devidamente caracterizadas e exploradas no ensino básico, o que serviu de mote para a apresentação de algumas situações de ensino para ilustrar os aportes orientadores sugeridos. Acreditamos que o caminho epistemológico trilhado viabilizou uma abertura para ampliar o quadro de significados em relação a outros tópicos presentes na Matemática Elementar, considerando-se como suporte a potencialidade presente nos eixos discreto/contínuo; exato/aproximado; finito/infinito, assim como no par determinístico/aleatório. / Considering Brazilian mathematics school textbooks as a primary research source, the knowledge to be taught still has a dual presentation, polarized in a pragmatic or theoretical way, what follows a thematic procedure pattern that favors an operational development involving exact, finite and deterministic contexts. In particular, these characteristics are seriously accentuated by the time of irrational numbers introduction at basic education, which leads to a restrictive approach. To overcome this situation, Bruner (1987) states that we should not postpone teaching key issues based on the belief that they are too hard, because the fundamental ideas of any subject can be taught at basic education, but it demands a work that overcome technical aspects, considerations that are equivalent to the resumption with aspects related to understanding. In this work, we had by hypothesis that the tension inherent on discrete/continuous, exact/approximate, finite/infinite pairs, extracted from analyses on real numbers epistemological evolution and described at Machado (2009), constitutes an essential conceptual pillar to establish a helpful framework to enable a significant irrational numbers approach, in order to compose an amalgam between technical and semantic aspects. Considering the necessary educational discussion involving this theme, we initially delimited an investigative context based on a qualitative study guided by the question How irrational numbers are approached in basic education, considering mathematics textbook as a source?\' in order to map this subject presentation at Middle and High School. The methodological foundation was inspired in meaning core, described in Aguiar and Ozella (2006), which aims to capture the sense that constitutes the speech content expressed inside mathematics scholar textbooks. The analysis from meaning core route reveals that, in the textbooks examined, the most known irrational numbers introduction occurs in a polarized way: some opt for a pragmatic bias and others by formal definition. However, it was found that after an initial approach, there is no further relationship between these options, which causes a rapid depletion of the tools to develop these themes, which limits the complexity understanding of irrational numbers in basic education. From the hypotheses and the empirical research, we intended to delineate contributions presented on the dialectical movement between discrete/continuous, finite/infinite and exact/approximate pairs, whose mutual connections permeate a \'space of meanings\', a field that allows to organize, to weave and to expand a network of meanings, as Machado (1995), favoring a framework for better understanding the irrational numbers development in basic school. The epistemological approach performed revealed a multiplicity of relationships involving irrational numbers and various subjects of mathematics curriculum, not properly characterized and exploited in basic education, references which served as contexts for the presentation of some teaching situations to illustrate the contributions guidance suggested. We believe that the epistemological path trodden enables an opening to increase possibilities of meanings in relation to other topics of Elementary Mathematics, considering as support the capability constituents presented in discrete/continuous, exact/approximate, finite/infinity axis, as well as in deterministic/random pair.
243

A kinetic model for grain growth

Henseler, Reiner 21 September 2007 (has links)
In dieser Arbeit wird eine detaillierte Analysis des konsistenten kinetischen Modells zum Kornwachstum von Fradkov durchgeführt. Dieses Modell beschreibt - basierend auf dem von Neumann--Mullins Gesetz - die Flächenänderung eines Korns abhängig von seiner Topologieklasse, d.h. der Anzahl der Kanten. Topologieänderungen werden durch Kopplungsterme zwischen den Gleichungen für die Anzahldichten der verschiedenen Topologieklassen beschrieben. Daraus resultiert ein unendlich-dimensionales System von Transportgleichungen mit tridiagonaler Kopplungsstruktur. Durch eine spezielle Wahl des Kopplungsgewichts, welche die Gleichungen nichtlinear und räumlich nichtlokal macht, wird das Modell konsistent. Nach einer Einführung wird das Modell von Fradkov im zweiten Kapitel hergeleitet; formale Rechnungen zeigen die Konsistenz des Modells auf. Im dritten Kapitel wird das Kopplungsgewicht a priori beschränkt. Dadurch kann im ersten Teil des vierten Kapitels Existenz und Eindeutigkeit von Lösungen für endlich-dimensionale Systeme gezeigt werden. Weitere Schranken an die Anzahldichten im fünften Kapitel ermöglichen den Grenzübergang hinsichtlich der Anzahl der Gleichungen im zweiten Teil des vierten Kapitels. Die Existenz von Lösungen des unendlich-dimensionalen Systems wird somit über eine geeignete Approximation gezeigt. Energiemethoden liefern Eindeutigkeit und stetige Abhängigkeit von den Daten. Im sechsten Kapitel wird das Langzeitverhalten untersucht. Besonderes Augenmerk liegt dabei auf stationären Lösungen eines reskalierten Systems als Kandidaten für selbstähnliche Lösungen. Abschließend wird das Lewis''sche Gesetz asymptotisch verifiziert. / The subject matter of this thesis is a detailed analysis of the self--consistent kinetic model for grain growth introduced by Fradkov. The model is based on the von Neumann--Mullins law describing the change of area of grains according to their topological class, i.e. the number of edges they have. Topological events are performed by coupling terms between equations for the number densities of different topological classes. The resulting system of transport equations is infinite-dimensional with a tridiagonal coupling structure. Self-consistency of this kinetic model is achieved by introducing a coupling''s weight making the equations nonlinear and nonlocal in space. We start with an introduction in the first chapter. Afterwards in the second chapter we derive Fradkov''s model and carry out formal calculations to illustrate self-consistency. In the third chapter we present a priori calculations mainly allowing us to bound the nonlinearity. This enables us to prove existence and uniqueness of solutions to finite-dimensional systems in the first part of the fourth chapter. Further bounds on the number densities established in the fifth chapter allow for passing to the limit concerning the number of equations in the second part of the fourth chapter. Therefore we prove existence of solutions to the infinite-dimensional system by a suitable approximation procedure. Uniqueness and continuous dependence on the data is then provided by energy methods. The sixth chapter focusses on long-time behaviour and mainly on stationary solutions of a rescaled system as candidates for self-similar solutions. Finally we prove Lewis'' law asymptotically.
244

Datalog on infinite structures

Schwandtner, Goetz 20 November 2008 (has links)
Datalog ist die relationale Variante der logischen Programmierung und ist eine Standard-Abfragesprache in der Datenbankentheorie geworden. Die Programmkomplexität von Datalog im bisherigen Hauptanwendungsgebiet, auf endlichen Strukturen, ist bekanntermassen in EXPTIME. Wir untersuchen die Komplexität von Datalog auf unendlichen Strukturen, motiviert durch mögliche Anwendungen von Datalog auf unendlichen Strukturen (z.B. linearen Ordnungen) im zeitlichen und räumlichen Schliessen, aber auch durch das aufkommende Interesse an unendlichen Strukturen bei verwandten theoretischen Problemen, wie Constraint Satisfaction Problems (CSP): Im Gegensatz zu endlichen Strukturen können Datalog-Berechnungen auf unendlichen Strukturen unendlich lange dauern, was zur Unentscheidbarkeit von Datalog auf unendlichen Strukturen führen kann. Aber auch in den entscheidbaren Fällen kann die Komplexität von Datalog auf unendlichen Strukturen beliebig hoch sein. Im Hinblick auf dieses Ergebnis widmen wir uns dann unendlichen Strukturen mit der niedrigsten Komplexität von Datalog: Wir zeigen, dass Datalog auf linearen Ordnungen (auch dichte und diskrete, mit oder ohne Konstanten und sogar gefärbte) und Baumordnungen EXPTIME-vollständig ist. Für die Bestimmung der oberen Schranke werden Werkzeuge für Datalog auf Ordnungen eingeführt: Ordnungstypen, Abstandstypen und typdisjunkte Programme. Die Typkonzepte liefern eine endliche Beschreibung der unendlichen Programmergebnisse und könnten auch für praktische Anwendungen von Interesse sein. Wir erzeugen spezielle typdisjunkte Programme, die sich ohne Rekursion lösen lassen. Ein Transfer unserer Methoden auf CSPs zeigt, dass CSPs auf unendlichen Strukturen mit beliebig hoher Zeitkomplexität vorkommen, wie Datalog. / Datalog is the relational variant of logic programming and has become a standard query language in database theory. The (program) complexity of datalog in its main context so far, on finite databases, is well known to be in EXPTIME. We research the complexity of datalog on infinite databases, motivated by possible applications of datalog to infinite structures (e.g. linear orders) in temporal and spatial reasoning on one hand and the upcoming interest in infinite structures in problems related to datalog, like constraint satisfaction problems: Unlike datalog on finite databases, on infinite structures the computations may take infinitely long, leading to the undecidability of datalog on some infinite structures. But even in the decidable cases datalog on infinite structures may have arbitrarily high complexity, and because of this result, we research some structures with the lowest complexity of datalog on infinite structures: Datalog on linear orders (also dense or discrete, with and without constants, even colored) and tree orders has EXPTIME-complete complexity. To achieve the upper bound on these structures, we introduce a tool set specialized for datalog on orders: Order types, distance types and type disjoint programs. The type concept yields a finite representation of the infinite program results, which could also be of interest for practical applications. We create special type disjoint versions of the programs allowing to solve datalog without the recursion inherent in each datalog program. A transfer of our methods shows that constraint satisfaction problems on infinite structures occur with arbitrarily high time complexity, like datalog.
245

O infinito: um obstáculo no estudo da Matemática / The infinite: an obstacle in the study of the mathematics

Amadei, Flavio Luiz 17 June 2005 (has links)
Made available in DSpace on 2016-04-27T16:58:42Z (GMT). No. of bitstreams: 1 dissertacao_flavio_luiz_amadei.pdf: 355407 bytes, checksum: 9113491693f07d1f5b01c29d5008a168 (MD5) Previous issue date: 2005-06-17 / nenhum / The research here presented approaches the notion of infinite under some different views, with the main purpose of indicating how imbricated was its formation as a mathematical concept and its consequences to the learning of mathematics. This research is supported by bibliographical study, presentation and analysis of the literature currently available on this subject. Some introductory mathematical concepts are presented on the notion of infinite, some aspects of the historical evolution of this notion in Mathematics, with special consideration to Bolzano s work The Paradoxes of Infinite , and data from other researches in the field of Mathematics Education. Analysis that intent to underline relationships between the epistemological and historical process of the notion of infinite, specially actual infinite, and the developmental process of human thinking in the learning of Mathematics, are presented as a conclusion / A pesquisa aqui apresentada visa abordar a noção de infinito sob alguns pontos de vista, com o objetivo principal de indicar quão imbricada foi a sua formação como conceito matemático e suas conseqüências para a aprendizagem da matemática. Esta pesquisa é desenvolvida a partir de estudo bibliográfico, apresentação e análise de textos sobre o assunto. São apresentados alguns conceitos introdutórios sobre a noção de infinito, alguns aspectos da evolução histórica dessa noção na matemática com destaque especial à obra "Os Paradoxos do Infinito" de Bolzano e resultados de pesquisas no âmbito da Educação Matemática. Análises que objetivam evidenciar relações existentes entre o processo epistemológico e histórico da noção de infinito, em especial do infinito atual e os processos de desenvolvimento do pensamento humano na aprendizagem da matemática, são apresentadas como fechamento
246

Sobre a incomunicabilidade humana / Sobre a incomunicabilidade humana

Alves, Claudenir Modolo 05 June 2009 (has links)
Esta dissertação versa sobre a incomunicabilidade humana. A pergunta problematizadora que temos como objetivo aprofundar é: o ser humano é, ontologicamente, um ser capaz de se comunicar? ou de outra forma: é possível a existência da comunicação? A hermenêutica imanente dos textos de natureza filosófica, seguida da reflexão analítica, nos aproxima da problemática sobre a incomunicabilidade humana, iluminando os enfoques chave do estado instaurado de incomunicação radical e generalizada, por outro lado a possibilidade do ser de relacionar-se e abrir a comunicação para sua existência. A possibilidade do ser humano de relacionar-se é mínima no sistema planetário de comunicação, o que nos faz concluir que vivemos na era da incomunicabilidade humana, por primeiro da incomunicabilidade entre eu e o outro. / This dissertation deals with human incommunicability. We intend to further study the following problematizing issue: Ontologically speaking, is the human being capable of communicating? In other words: can communication exist? The immanent hermeneutics of philosophical texts, followed by analytical reflection, leads us to the problem of human incommunicability, throws light on key approaches to the state of radical and generalized incommunication, and, on the other hand, the possibility for human beings to establish relationships and open lines of communication for their survival. The planets communication system allows for minimal possibilities of human beings establishing relationships; we have, therefore, to conclude that we live in an era of human incommunicability, starting with the incommunicability between the self and others.
247

ε-SUPERPOSITION AND TRUNCATION DIMENSIONS IN AVERAGE AND PROBABILISTIC SETTINGS FOR ∞-VARIATE LINEAR PROBLEMS

Dingess, Jonathan M. 01 January 2019 (has links)
This thesis is a representation of my contribution to the paper of the same name I co-author with Dr. Wasilkowski. It deals with linear problems defined on γ-weighted normed spaces of functions with infinitely many variables. In particular, I describe methods and discuss results for ε-truncation and ε-superposition methods. I show through these results that the ε-truncation and ε-superposition dimensions are small under modest error demand ε. These positive results are derived for product weights and the so-called anchored decomposition.
248

張湛《列子注》貴虛思想研究 / A Study on Chang - Chan's Theories of Emptiness from the Book of 《Lieh Tzu Chu》

吳慕雅, Wu, Mu Ya Unknown Date (has links)
張湛《列子注》長久以來在學術界未受到重視,但是在整個魏晉玄學的發展史上(尤其是東晉玄學)實具有不可磨滅的價值,因此對於張湛的玄學思想應給予什麼樣的評價?張湛的「貴虛」思想與《列子》的「貴虛」究竟有什麼不同?他的理論是否可以名之為「貴虛論」?張湛的思想體系只是單純的雜揉各家的說法、還是又提出了一些新的命題及概念?這些都是在探討張湛思想所欲解決的問題。本文擬分為六章,以「貴虛」為理論核心,再探討相關的幾個重要的子題--言意觀、力命論、天道觀、聖人論等,將張湛的行為及思考模式作一時代的定位。本文各章重點如下:第一章緒論,先宏觀介紹東晉玄學的特色及《列子注》「貴虛」的意涵,並對張湛是否偽作《列子》疑案作一釐清。第二章言意觀,說明《列子注》言意之辨的內涵,從去知忘言的語言模式及名實與公私二方面論述。進而再探討張湛的思考脈絡及思維方式。第三章天道觀,探討有無之辨的思想背景及思想內涵,從道與的關係、萬有生化的情形、宇宙的生成三方面申說。第四章力命論,主要探討理與力命的關係及「為我」與「知命」觀念的矛盾與調和。第五章聖人之道,說明張湛「聖人」模式的內涵及儒道調和的意義,並進一步闡明張湛對於覺與夢的辨別及具體的修養之方。第六章結論,對張湛思想體系的檢討及評價。
249

Subordinação Adverbial : um estudo cognitivo sobre o infinitivo, o clítico SE e as formas verbais finitas em proposições adverbiais do Português Europeu / Adverbial subordination : a cognitive study on the infinitive, the clitic SE and finite verb forms in European Portuguese adverbial clauses

Vesterinen, Rainer January 2006 (has links)
<p>The aim of this study is to analyse the variation between infinitive and finite verb adverbial clauses in European Portuguese. In order to understand this variation, three central questions are raised: (1) What determines the use of the uninflected vs. the inflected infinitive in same-subject adverbial clauses? (2) What does the pronoun SE signal in these adverbial clauses? (3) What difference is there between the use of the inflected infinitives vs. finite verbs in different subject adverbial clauses?</p><p>Earlier investigations about these three questions are discussed. One conclusion of this review is that former research almost exclusively has been conducted from a traditional or formalistic point of view that has given priority to structural descriptions instead of semantic or conceptual explanations. In contrast to this, the present study endeavours to examine these issues from a cognitive linguistic perspective.</p><p>It is claimed that the use of the inflected infinitive in adverbial same-subject clauses may be explained by contextual factors which create a cognitive need to highlight the subject of the adverbial clause. Further, an analysis about how the grammatical micro-context can determine the interpretation of the clitic pronoun SE as a marker for a generic trajector is conducted. It is also argued that the difference between infinitive and finite adverbial clauses can bee explained by means of theories of subjectification and mental spaces.</p><p>The conclusion is drawn that a cognitive approach to grammar can, indeed, shed light on the issues considered. In particular, it is shown that different adverbial constructions can express different conceptual meaning. In the light of this fact, other issues concerned with finite and infinite verb forms are raised.</p>
250

Becoming the New Man in Post-PostModernist Fiction: Portrayals of Masculinities in David Foster Wallace's Infinite Jest and Chuck Palahnuik's Fight Club

Delfino, Andrew Steven 03 May 2007 (has links)
While scholars have analyzed the masculinity crisis portrayed in American fiction, few have focused on postmodernist fiction, few have examined masculinity without using feminist theory, and no articles propose an adequate solution for ending normative masculinity’s dominance. I examine the masculinity crisis as it is portrayed in two postmodernist novels, David Foster Wallace’s novel Infinite Jest and Chuck Palahniuk’s novel Fight Club. Both novels have male characters that ran the gamut of masculinities, but those that are the most successful at avoiding gender stereotypes (Donald Gately in Infinite Jest, and the narrator in Fight Club) develop a masculinity which incorporates strong, phallic masculinity and nurturing, testicular masculinity, creating a balanced gender. At the same time, both novels examine postmodernist fiction’s future. Post-postmodernist fiction, similar to well-rounded masculinity, seeks to be more emotionally open with the reader while still using irony and innovation for meaningful effects, not just to be clever.

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