The problem of inferring or reconstructing the material properties (cross sections) of a domain through noninvasive techniques, methods using only input and output at the domain boundary, is attempted using the governing laws of neutron diffusion theory as an optimization constraint. A standard Lagrangian was formed consisting of the objective function and the constraints to satisfy, which was minimized through optimization using a line search method. The chosen line search method was Newton's method with the Armijo algorithm applied for step length control. A Gaussian elimination procedure was applied to form the Schur complement of the system, which resulted in greater computational efficiency. In the one energy group and multi-group models, the limits of parameter reconstruction with respect to maximum reconstruction depth, resolution, and number of experiments were established. The maximum reconstruction depth for one-group absorption cross section or multi-group removal cross section were only approximately 6-7 characteristic lengths deep. After this reconstruction depth limit, features in the center of a domain begin to diminish independent of the number of experiments. When a small domain was considered and size held constant, the maximum reconstruction resolution for one group absorption or multi-group removal cross section is approximately one fourth of a characteristic length. When finer resolution then this is considered, there is simply not enough information to recover that many region's cross sections independent of number of experiments or flux to cross-section mesh refinement. When reconstructing fission cross sections, the one group case is identical to absorption so only the multi-group is considered, then the problem at hand becomes more ill-posed. A corresponding change in fission cross section from a change in boundary flux is much greater then change in removal cross section pushing convergence criteria to its limits. Due to a more ill-posed problem, the maximum reconstruction depth for multi-group fission cross sections is 5 characteristic lengths, which is significantly shorter than the removal limit. To better simulate actual detector readings, random signal noise and biased noise were added to the synthetic measured solutions produced by the forward models. The magnitude of this noise and biased noise is modified and a dependency of the maximum magnitude of this noise versus the size of a domain was established. As expected, the results showed that as a domain becomes larger its reconstruction ability is lowered which worsens upon the addition of noise and biased noise.

In the course Discrete Deterministic Chaos, Dr. Mark Daniels introduces students to Chaos Theory and explores many topics within the field. Students prove many of the key results that are discussed in class and work through examples of each topic. Connections to the secondary mathematics curriculum are made throughout the course, and students discuss how the topics in the course could be implemented in the classroom. This paper will provide an overview of the topics covered in the course, Discrete Deterministic Chaos, and provide additional discussion on various related topics. / text

A concept of a well-posed problem was initially introduced by J. Hadamard in 1923, who expressed the idea that every mathematical model should have a unique solution, stable with respect to noise in the input data. If at least one of those properties is violated, the problem is ill-posed (and unstable). There are numerous examples of ill- posed problems in computational mathematics and applications. Classical numerical algorithms, when used for an ill-posed model, turn out to be divergent. Hence one has to develop special regularization techniques, which take advantage of an a priori information (normally available), in order to solve an ill-posed problem in a stable fashion. In this thesis, theoretical and numerical investigation of Tikhonov's (variational) regularization is presented. The regularization parameter is computed by the discrepancy principle of Morozov, and a first-kind integral equation is used for numerical simulations.

We present a numerical method to solve the optimal transport problem with a quadratic cost when the source and target measures are periodic probability densities. This method relies on a numerical resolution of the corresponding Monge-Ampère equation. We use an existing Newton-like algorithm that we generalize to the case of a non uniform final density. The main idea consists of designing an iterative scheme where the fully nonlinear equation is approximated by a non-constant coefficient linear elliptic PDE that we discretize and solve at each iteration, in two different ways: a second order finite difference scheme and a Fourier transform (FT) method. The FT method, made possible thanks to a preconditioning step based on the coefficient-averaged equation, results in an overall O(P LogP )-operations algorithm, where P is the number of discretization points. We prove that the generalized algorithm converges to the solution of the optimal transport problem, under suitable conditions on the initial and final densities. Numerical experiments demonstrating the robustness and efficiency of the method on several examples of image processing, including an application to multiple sclerosis disease detection, are shown. We also demonstrate by numerical tests that the method is competitive against some other methods available.

Orientador: Lizete Maria Orquiza de Carvalho / Banca: Roberto Nardi / Banca: João Zanetic / Resumo: É corrente entre os pesquisadores a necessidade de inserção de História. Filosofia e Sociologia da Ciência no ensino de ciências, assim como esta inserção é recorrentemente apontada como uma solução para a suposta crise que invadiu o ensino nesta modalidade. Insatisfeitos com o rumo que estas pesquisas estão tomando, delineamos nosso problema de pesquisa. Explicitamos nossa concepção de educação embasada principalmente pela obra do educador Paulo Freire, ou seja, apresentamos nossa concepção de educação dialógica-problematizadora na vertente emancipadora. Fazemos uma aproximação entre a concepção freiriana de educação e o ensino de ciências, a fim de estabelecer uma concepção de ensino de ciências, bem como do ensino de física do qual compartilhamos. Nessa concepção de ensino de ciências apresentamos a finalidade pela qual pretendemos resgatar a História, Filosofia e Sociologia da Ciência, HFSC, argumentando em favor de sua inseparabilidade com a Ciência no ensino de ciências. Apresentamos a Experiência do Balde de Newton e a finalidade que a mesma teria nessa concepção. Concluímos que a construção de enunciados sobre a experiência dp Balde de Newton, através de seus consequentes pronunciamentos e sua volta problematizada ao sujeito, proporcionou aos alunos uma transformação da realidade / Abstract: It is a common practi ce among researches the need of entering into History, Philosophy and Sociology of Science in science teaching, and this integration is repeatedly cited as a solution to the supposed crisis that broke into the school championship. Unhappy with the way these survey are taking, we delicated our research problem. We explicited our conception of education based mainly on the work of eductor Paulo Freire, that is, we present our vision of dialogic-problematizing education in the shed for liberation. We make a connection between the desing Freirien education and science education in order to establish a conception of science teaching and the teaching of physics which we share. In this conception of science education we present the purpose we intend redeem the History, Philosophy and Sociology of Science, HFSC, arguing for the inseparability of Science in science education. We present the experience of Newton's bucket and the the purpose that it would have this view. We conclude that the construction of statements about the experience of Newton's bucket through this consequent pronouncements and his return problematized to the subject gave the pupils a changing reality / Mestre

In this paper we develop new and improved results in the numerical solution of the coupled algebraic Riccati equations. First we provide improved matrix upper bounds on the positive semidefinite solution of the unified coupled algebraic Riccati equations. Our approach is largely inspired by recent results established by Liu and Zhang. Our main results tighten the estimates of the relevant dominant eigenvalues. Also by relaxing the key restriction our upper bound applies to a larger number of situations. We also present an iterative algorithm to refine the new upper bounds and the lower bounds and numerically compute the solutions of the unified coupled algebraic Riccati equations. This construction follows the approach of Gao, Xue and Sun but we use different bounds. This leads to different analysis on convergence. Besides, we provide new matrix upper bounds for the positive semidefinite solution of the continuous coupled algebraic Riccati equations. By using an alternative primary assumption we present a new upper bound. We follow the idea of Davies, Shi and Wiltshire for the non-coupled equation and extend their results to the coupled case. We also present an iterative algorithm to improve our upper bounds. Finally we improve the classical Newton's method by the line search technique to compute the solutions of the continuous coupled algebraic Riccati equations. The Newton's method for couple Riccati equations is attributed to Salama and Gourishanar, but we construct the algorithm in a different way using the Fr\'echet derivative and we include line search too. Our algorithm leads to a faster convergence compared with the classical scheme. Numerical evidence is also provided to illustrate the performance of our algorithm.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第17968号 / 情博第512号 / 新制||情||91(附属図書館) / 30798 / 京都大学大学院情報学研究科数理工学専攻 / (主査)教授 中村 佳正, 教授 西村 直志, 准教授 山下 信雄 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

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No / Online games require small data of 3D models for low storage costs, quick transmission over the Internet, and efficient geometric processing to achieve real-time performance, and new techniques of facial blendshapes to create natural facial animation. Current geometric modelling and animation techniques involve big data of geometric models and widely applied facial animation using linear interpolation cannot generate natural facial animation and create special facial animation effects. In this paper, we propose a new approach to integrate the strengths of ODE (ordinary differential equation) sweeping surfaces and Newton's second law-based facial blendshapes to create 3D models and their animation with small data, high efficiency, and ability to create special facial effects.

Neste estudo, apresentamos conteúdos matemáticos adaptáveis tanto para os anos finais do ensino fundamental quanto para o ensino médio. Iniciamos com um conjunto de ideias preliminares: indução matemática, triângulo de Pascal, Binômio de Newton e relações trigonométricas, para a obtenção de fórmulas de somas finitas, em que os valores das parcelas são computados sobre números inteiros consecutivos, e da técnica de transformação de soma finita em telescópica. Enunciamos Progressões Aritméticas e Geométricas como sequências numéricas e suas propriedades, obtendo a soma de seus n primeiros termos, associando com propriedades do triângulo de Pascal. Por fim, descrevemos Funções Aritméticas, Funções Aritméticas Totalmente Multiplicativas e Fortemente Multiplicativas, como sequências de números naturais, com suas operações e propriedades, direcionando ao objetivo de calcular o número de divisores naturais de n, a soma de todos os divisores naturais de n, e assim por diante. Como consequência, exibimos a fórmula de contagem do número de polinômios mônicos irredutíveis. / In this study, we present mathematical content that is adaptable to both of the final years of elementary school and to high school. We start with a set of preliminary ideas: mathematical induction, Pascal\'s triangle, Newton\'s binomial and trigonometric relations, to obtain finite sum formulas, where the parts are computed on consecutive integers, and the technique for transforming a finite sum in telescopic one. We state the Arithmetic and Geometric Progressions as numerical sequences and study their properties, obtaining the sum of their n first terms, associating with properties of the Pascal\'s triangle. Finally, we describe the Arithmetic, Totally Multiplicative and Strongly Multiplicative Arithmetic Functions, as sequences of natural numbers, with their operations and properties, as a way to calculating the number of natural divisors of n, the sum of all natural divisors of n, and so on. As a consequence, we obtain the counting formula of the number of irreducible mononical polynomials.