Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Neste trabalho investigamos diversos fenÃmenos de transporte tendo lugar atravÃs de meios irregulares por meio de simulaÃÃo computacional. Inicialmente, tratamos do efeito da desordem crÃtica em redes percolantes de poros sujeitas à difusÃo e reaÃÃo quÃmica. Verificamos a existÃncia de trÃs regimes distintos, determinados pelo parÃmetro adimensional E=D/(Kl^2), onde D à a difusÃo molecular, K o coeficiente de reaÃÃo quÃmica e l um comprimento caracterÃstico. Para valores baixos de E, o fluxo de reagente que penetra a rede obedece à relaÃÃo de escala clÃssica, F~LE^(1/2). Para valores intermediÃrios de E, a influÃncia da morfologia fractal do agregado de percolaÃÃo resulta em um regime anÃmalo, F~L^(A/2)E^B, com um expoente B=0.34. Para valores altos de E, o fluxo de reagente atinge um limite de saturaÃÃo, F_SAT, e escala com o tamanho do sistema na forma F_SAT=L^A, onde A=1.89 corresponde à dimensÃo fractal do agregado incipiente de percolaÃÃo. Em uma segunda etapa do trabalho, analisamos o efeito da geometria irregular na desativaÃÃo seqÃencial de uma interface acessada por difusÃo. Aplicando o conceito de zona ativa, propomos uma conjectura que se constitui numa extensÃo do teorema de Makarov. Na terceira parte deste trabalho, investigamos o transporte estacionÃrio de calor no escoamento de um fluido atravÃs de um tubo bidimensional, cujas paredes sÃo interfaces irregulares. Mais uma vez, utilizando o conceito de zona ativa, investigamos o efeito da geometria da interface na eficiÃncia de troca tÃrmica do sistema em diferentes condiÃÃes difusivo-convectivas. Em condiÃÃes nas quais o mecanismo de transporte dominante à a conduÃÃo, a comparaÃÃo entre os resultados dos tubos liso e rugosos indica que o efeito da rugosidade à quase desprezÃvel sobre a eficiÃncia de dispositivos de transporte de calor. Por outro lado, quando a convecÃÃo torna-se dominante, a rugosidade passa a ter um papel importante e, em geral, o fluxo de calor e o comprimento da zona ativa aumentam com a rugosidade da interface de troca. Finalmente, mostramos que esse Ãltimo comportamento està relacionado com as zonas de recirculaÃÃo, presentes nas reentrÃncias da geometria fractal. / In this work, we investigate different transport phenomena through irregular media by means of numerical simulations. Initially, we study the effect of the critical percolation disorder on pore networks under diffusion-reaction conditions. Our results indicate the existence of three distinct regimes of reactivity, determined by the dimensionless parameter E=D/(Kl^2), where D is the molecular diffusivity of the reagent, K is its chemical reaction coefficient, and l is the length scale of the pore. At low values of E, the flux of the reacting species penetrating the network follows the classical scaling behavior, namely F~LE^(1/2). At intermediate values of E, the influence of the fractal morphology of the percolating cluster results in an anomalous behavior, F~L^(A/2)E^B, with an exponent B=0.34. At high values of E, the flux of the reagent reaches a saturation limit, F_SAT, that scales with the system size as F_SAT=L^A, with an exponent A=1.89, corresponding to the fractal dimension of the sample-spanning cluster. In the second part of this work, we study how the irregularity of the geometry influences the sequential deactivation of an interface accessed by diffusion. By using the notion of active zone, we propose a conjecture which constitutes an extension of Makarov theorem. In the third part, we investigate the steady-state heat transport in a fluid flowing through a two-dimensional channel whose walls are irregular interfaces. Once more, we apply the notion of active zone to investigate the effect of the interface geometry on the heat exchange efficiency of the system for different conductive-convective conditions. Compared with the behavior of a channel with smooth interfaces and under conditions in which the mechanism of heat conduction dominates, the results indicate that the effect of roughness is almost negligible on the efficiency of the heat transport system. On the other hand, when the convection becomes dominant, the role of the interface roughness is to generally increase both the heat flux across the wall as well as the active length of heat exchange, when compared with the smooth channel. Finally, we show that this last behavior is closely related with the presence of recirculation zones in the reentrant regions of the fractal geometry.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho consiste em um relato sobre a origem da Geometria Fractal, tendo em destaque a figura de Benoît Mandelbrot, identificado como pioneiro nesta área, cujo fractal leva seu nome. Mostra os fractais pioneiros, assim como a construção destes através da ferramenta computacional "Asymptote". É necessário dizer que, a partir da construção destes, percebe-se, com facilidade um intenso uso de conteúdos presentes no currículo escolar do ensino básico, como por exemplo o cálculo de perímetro e de áreas de figuras planas, potenciação, problemas de contagens, entre outros, os quais podem ser abordados com o intuito de introduzir tal conteúdo ou mesmo aprofundá-lo. Por fim, faremos uso de Indução Matemática para demonstrar algumas destas fórmulas encontradas. / This work consists the historic report of the origin of Fractal Geometry, and highlighted the figure of Benoît Mandelbrot, identified as pioneer in this area, whose fractal bears his name. Shows the pioneers fractals, as well as the construction of these using the computational tool "Asymptote". It must be said that, from the construction of these, it is noted, easily a intense use of contents present in the curriculum of basic education, such as the calculation of perimeter and area of plane figures, potentiation, in counts problems, among others, they can be addressed in order to start the study of such content or to same deepen it. Finally, we will make use of Mathematical Induction to demonstrate some of the formulas found.

The theoretical focus of this study is Meaning in Architecture. The study does not draw from history or popular culture for meaning, but will aim to transcend Post-modern concepts by focusing on the contemporary condition and archetypal forms as a result of history and popular culture. This is done through the use of fractal geometry and deals with the questions that arise regarding signification. Fractals can be considered a subdivision of the language of mathematics and will be utilised as mediation between the reality of our world and the generation of form for the purpose of design. This is explored in two analogies, Architecture and Mathematics; and Architecture and Language. Through this process, subjectivity relating to form is removed as the design was developed in conjunction with the area in which it manifests, through the transformation of quantifiable entities into form. The programme and the process have become a unified whole in that mathematical concepts were utilised to design a building to house people involved with mathematics. The aim of the design proposal is to contribute to the urban landscape of Tshwane by allowing access to facilities in which training in mathematics and computer science can be achieved and to allow individuals to come to a place of self-actualization. The design is defined as a snapshot of the contemporary condition and therefore makes use of passive and active technologies to create a habitable environment. It is imperative to realise that society is in a process of transition and this can be embraced by combining ‘green’ and ‘non-green’ design approaches, while working towards more energy-efficient design solutions. Copyright / Dissertation (MArch(Prof))--University of Pretoria, 2010. / Architecture / unrestricted

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In this dissertation, we study the dynamics, fractal geometry and the topology of the Julia set of functions in the family H which is a set in the class S, the Speiser class of entire transcendental functions which have only finitely many singular values. One can think of a function from H as a generalized expanding function from the cosh family. We shall build a version of thermodynamic formalism for functions in H and we shall show among others, the existence and uniqueness of a conformal measure. Then we prove a Bowen's type formula, i.e. we show that the Hausdorff dimension of the set of returning points, is the unique zero of the pressure function. We shall also study conjugacies in the family H, perturbation of functions in the family and related dynamical properties. We define Perron-Frobenius operators for some functions naturally associated with functions in the family H and then, using fundamental properties of these operators, we shall prove the important result that the Hausdorff dimension of the subset of returning points depends analytically on the parameter taken from a small open subset of the n-dimensional parameter space.

Orientador: Vanderlei Horita / Banca: Marcela Luciano Vilela de Souza / Banca: João Carlos Ferreira Costa / Resumo: A proposta deste trabalho é oferecer algumas atividades para desenvolvimento em sala de aula, com alunos de educação básica, envolvendo os fractais geométricos. A caracterização dessas figuras é feita através de duas de suas principais características: a autossemelhança e a dimensão não necessariamente inteira, o que possibilita a abordagem de temas como sequências numéricas e noções de limites com alunos de ensino médio. Tais atividades também podem ser utilizadas como complemento às aulas de progressões aritméticas e geométricas, logaritmos e área de triângulos equiláteros / Abstract: The purpose of this work is to provide some activities to be developed in the classroom with students from basic education, involving geometric fractals. The characterization of these objects is made through two of its main features: self-similarity and its dimension not necessarily entire, which enables the approach to issues such as numerical sequences and notions of limits with high school students. Such activities may also be used as a supplement to lessons of arithmetic and geometric progressions, logarithms and area of equilateral triangles / Mestre

I study sets of attractors and non-attractors of finite iterated function systems. I provide examples of compact sets which are attractors of iterated function systems as well as compact sets which are not attractors of any iterated function system. I show that the set of all attractors is a dense Fs set and the space of all non-attractors is a dense Gd set it the space of all non-empty compact subsets of a space X. I also investigate the small trans-finite inductive dimension of the space of all attractors of iterated function systems generated by similarity maps on [0,1].

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In this work I explore the geometry found both in the narrative structures and the internal shapes proposed in Jorge Luis Borges’ short stories and seek to arrive at new interpretations of those works by mapping out—in graphical form—the shapes found therein. I move from basic two-dimensional shapes (lines, triangles, quadrilaterals) to those involving the element of temporality and atemporality (circles, interruptive loops, chiasmus) to shapes dealing with repetition—both geometric and temporal—and eternity (labyrinths, fractals, and Alephs). In each case and for each short story analyzed, either an existent interpretation is favored or a new interpretation is set forth.

京都大学 / 新制・課程博士 / 博士(情報学) / 甲第24262号 / 情博第806号 / 新制||情||136(附属図書館) / 京都大学大学院情報学研究科先端数理科学専攻 / (主査)教授 木上 淳, 教授 磯 祐介, 准教授 白石 大典 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM