Due to the fast development in 3D technology during recent decades, many approaches in 3D representation technologies have been proposed worldwide. In order to get an accurate information to render a 3D representation, more data need to be recorded compared to normal video sequence. In this case, how to find an efficient way to transmit the 3D representation data becomes an important part in the whole 3D representation technology. Recent years, many coding schemes based on the principle of encoding the depth have been proposed. Compared to the traditional multiview coding schemes, those new proposed schemes can achieve higher compression efficiency. Due to the development of depth capturing technology, the accuracy and quality of the reconstructed depth image also get improved. In this thesis we propose an efficient depth data compression scheme for 3D images. Our proposed depth data compression scheme is platelet based coding using Lagrangian optimization, quadtree decomposition and quadratic curve fitting. We study and improve the original platelet based coding scheme and achieve a compression improvement of 1-2 dB compared to the original platelet based scheme. The experimental results illustrate the improvement provided by our scheme. The quality of the reconstructed results of our proposed curve fitting based platelet coding scheme are better than that of the original scheme.

Sem dúvida a questão central em Dinâmica Holomorfa é aquela sobre a densidade de hiperbolicidade. Temos a seguinte conjectura devida a Pierre Fatou: No espaço das aplicações racionais de grau d o conjunto das aplicações racionais hiperbólicas neste espaço formam um subconjunto aberto e denso. Nem mesmo para a família dos polinômios quadráticos esta questão foi respondida. Para a família quadrática este problema é equivalente a mostrar a não existência de polinômios quadráticos que suportam sobre o seu conjunto de Julia um campo de linhas invariante. Devido a resultados de Jean-Christophe Yoccoz sabemos da não existência de campos de linhas invariante para polinômios quadráticos no máximo finitamente renormalizáveis. Nesta dissertação é mostrado que um polinômio quadrático infinitamente renormalizável satisfazendo certa hipótese geométrica, denominada robustez, não suporta sobre o seu Julia um campo de linhas invariante. Esta prova foi obtida por Curtis T. McMullen e publicada em [McM1]. Os avanços na teoria de renormalização e quanto ao problema da densidade de hiperbolicidade e problemas relacionados tem contado com a colaboração de inúmeros renomados matemáticos como Mikhail M. Lyubich, Artur Ávila, Mitsuhiro Shishikura, Curtis T. McMullen, Jean-Christophe Yoccoz, Sebastien van Strien, Hiroyuki Inou, dentre outros / Undoubtedly one of the central open questions in Holomorphic Dynamics is about proving the density of hyperbolicity. That question was first raised by Pierre Fatou: In the space of rational functions of degree d the set of hyperbolic rational functions form a open and dense subset. Not even for the family of quadratic polynomials this question been answered. For this particular quadratic family the problem is equivalent to showing the non-existence of quadratic polynomial with a Julia set supporting an invariant line field. Due to results by Jean-Christophe Yoccoz we already know the non-existence of invariant line fields for the quadratic polynomials that are at most finitely renormalizable. In this dissertation it is shown that an infinitely renormalizable quadratic polynomial satisfying a certain geometric hypotesis, called robustness, does not have an invariant line field supported on its Julia set. This proof was obtained by Curtis T. McMullen and published in [McM1]. Many advances on the theory of renormalization and on the problem of density of hyperbolicity have been already accomplished through the collective work of several renowned mathematicians such as Mikhail M. Lyubich, Artur Ávila, Mitsuhiro Shishikura, Curtis T. McMullen, Jean-Christophe Yoccoz, Sebastien van Strien, Hiroyuki Inou among others.

Este trabalho trata das seções cônicas (circunferência, elipse, hipérbole e parábola), curvas planas obtidas pela intersecção de um cone circular reto com um plano. O objetivo do trabalho é representar algebricamente essas figuras geométricas. As referidas curvas serão estudadas num sistema cartesiano ortogonal. Nos primeiros capítulos as cônicas serão estudadas individualmente com relação aos seus elementos e às equações que descrevem cada curva. Serão apresentadas as equações canônicas, as equações paramétricas e as equações em coordenadas polares dentre outras. Destaque especial é dado às retas tangentes a essas curvas. No último capítulo as cônicas serão relacionadas através da equação geral. Serão estudados métodos que permitem a identificação e caracterização dessas curvas a partir da equação geral. / This paper deals with the conic sections (circumference, ellipse, hyperbola and parabola), plane curves obtained by the intersection of a right circular cone with a plane. The objective of this work is to represent these geometric figures algebraically. These curves will be studied in an orthogonal Cartesian system. In the first chapters the conics will be studied individually with respect to their elements and to the equations that describe each curve. The canonical equations, the parametric equations and the equations in polar coordinates, among others, will be presented. Special emphasis is given to the tangent lines to these curves. In the last chapter the conics will be related through the general equation. Methods will be studied that allow the identification and characterization of these curves from the general equation.

Gao Jianjun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 75-76). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Solution Framework Using Dynamic Programming --- p.7 / Chapter 2.1 --- Difficulty of using dynamic programming --- p.8 / Chapter 2.2 --- Scalar-state problems --- p.12 / Chapter 2.3 --- Time-invariant system --- p.17 / Chapter 2.4 --- Illustrative example of a scalar-state problem --- p.21 / Chapter 3 --- Cardinality Constrained Quadratic Optimization --- p.26 / Chapter 3.1 --- Reformulation --- p.27 / Chapter 3.2 --- NP hardness --- p.31 / Chapter 3.3 --- Solving CCQP with an efficient branch and bound method --- p.34 / Chapter 3.3.1 --- Efficient branch and bound algorithm --- p.34 / Chapter 3.3.2 --- Geometrical interpretation of the proposed ranking order --- p.48 / Chapter 3.3.3 --- Additional algorithmic ideas for enhancing computational efficiency --- p.56 / Chapter 3.4 --- Numerical example and computational results --- p.60 / Chapter 4 --- Summary and Future Work --- p.73

Finding integer solutions to linear equations has various real world applications. In the thesis, we investigate its application to the reachability analysis of Petri nets. Introduced by Petri in 1962, Petri net has been a powerful mathematical formalism for modeling, analyzing and designing discrete event systems. In the research community of Petri nets, finding a feasible path from the initial state to the target state in Petri net, known as reachability analysis, is probably one of the most important and challenging subjects. The reachability algebraic analysis is equivalent to finding the nonnegative integer solutions to a fundamental equation constructed from the Petri net. We apply our algorithm in this thesis to reachability analysis of Petri net by finding the nonnegative integer solutions to the fundamental equation. / Finding the optimal binary solution to a quadratic object function is known as the Binary Quadratic Programming problem (BQP), which has been studied extensively in the last three decades. In this thesis, by investigating geometric features of the ellipse contour of a concave quadratic function, we derive new upper and lower bounding methods for BQP. Integrating these new bounding schemes into a proposed solution algorithm of a branch-and-bound type, we propose an exact solution method in solving general BQP with promising preliminary computational results. Meanwhile, by investigating some special structures of the second order matrix and linear term in BQP, several polynomial time algorithms are discussed to solve some special cases of BQP. / In the realm of integer programming, finding integer solutions to linear equations is another important research direction. The problem is proved to be NP-Complete, and several algorithms have been proposed such as the algorithm based on linear Diophantine equations as well as the method based on Groebner bases. Unlike the traditional algorithms, the new efficient method we propose in this thesis is based on our results on zero duality gap and the cell enumeration of an arrangement of hyperplanes in discrete geometry. / Integer programming plays an important role in operations research and has a wide range of applications in various fields. There are a lot of research directions in the area of integer programming. In this thesis, two main topics will be investigated in details. One is to find the optimal binary solution to a quadratic object function, and the other is to find integer solutions to linear equations. / Gu, Shenshen. / Adviser: Wang Jun. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 98-103). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Although cardinality constraints naturally arise in many applications, e.g., in portfolio selection problems of choosing small number of assets from a large pool of stocks or dynamic portfolio selection problems with limited trading dates within a given time horizon and in subset selection of the regression analysis, the state-of-the-art in cardinality constrained optimization has been stagnant up to this stage, largely due to the inherent combinatorial nature of such hard problems. We focus in this research on developing efficient and implementable solution algorithms for cardinality constrained optimization by investigating prominent structures and hidden properties of such problems. More specifically, we develop solution algorithms for four specific cardinality constrained optimization problems, including (i) the cardinality constrained linear-quadratic control problem, (ii) the optimal control problem of linear switched system with limited number of switching, (iii) the time cardinality constrained dynamic mean- variance portfolio selection problem, and (iv) cardinality constrained quadratic optimization problem. Taking advantages of a linear-quadratic structure of cardinality constrained optimization problems, we strive for analytical solutions when possible. More specifically, we derive an analytical solution for problem (iii) and obtain for both problems (i) and (ii) semi-analytical expressions of the solution governed by a family of Ricatti-like equations, which still suffer an exponentially growing complexity. To achieve high-performance of the solution algorithm, we devise algorithms of a branch and bound (BnB) type with various tight and computationally-cheap lower bounds achieved by identifying suitable SDP formulations and by exploiting geometric properties of the problem. We demonstrate efficiency of our proposed solution schemes evidenced from numerical experiments and present a firm step-forward in tackling this long-standing challenge of cardinality constrained optimization. / Gao, Jianjun. / Adviser: Duan Li. / Source: Dissertation Abstracts International, Volume: 72-11, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 134-142). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-08-28T20:05:57Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Funções quadráticas - Fábio Antonio Leão Sousa.pdf: 2458262 bytes, checksum: 7dfbda1fa1adf31189726f9cdce14bd6 (MD5) / Made available in DSpace on 2014-08-28T20:05:57Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Funções quadráticas - Fábio Antonio Leão Sousa.pdf: 2458262 bytes, checksum: 7dfbda1fa1adf31189726f9cdce14bd6 (MD5) Previous issue date: 2013-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This paper aims to expand the knowledge about the quadratic function providing a new perspective on the behavior of its graph. Initially, presents the definition of Quadratic Function, as well as the basic concepts involving the Parable. Secondly, the Parable is characterized, describing the symmetry existing in relation to the vertical axis which contains the vertex, the intervals of growth and decrease of the function and the behavior of curve described by the graph. Finally, this study relates each coefficient of the quadratic function to the graph, giving a geometric character to the coefficients through the variation of its values. / Este trabalho tem como objetivo ampliar os conhecimentos sobre a função quadrática, proporcionando uma nova perspectiva sobre o comportamento de seu gráfico. Inicialmente, apresenta a definição da função quadrática, bem como, os conceitos básicos que envolve a parábola. Em segundo lugar, caracteriza-se a parábola, descrevendo a simetria existente em relação ao eixo vertical que contém o vértice, os intervalos de crescimento e decrescimento da função e o comportamento da curva descrita pelo gráfico. Finalmente, relaciona cada coeficiente da função quadrática ao gráfico dando um caráter geométrico aos coeficientes através da variação de seus valores.

The quadratic assignment problem (QAP) is known to be one of the most computationally difficult combinatorial problems. Optimally solvable instances of the QAP remain of size n ≤ 40 with heuristics used to solve instances in the range 40 ≤ n ≤ 256. In this thesis we develop a local optimization algorithm called GradSwaps (GS). GS uses the first-order Taylor approximation (FOA) to efficiently determine improving swaps in the solution. We use GS to locally optimize instances of the QAP of size 1000 ≤ n ≤ 70000 where the data matrices are given in factored form, enabling efficient computations. We give theoretical background and justification for using the FOA and bound the error inherent in the approximation. A strategy for extending GS to larger scale QAPs using blocks of indices is described in detail. Three novel large-scale applications of the QAP are developed. First, a strategy for data visualization using an extreme learning machine (ELM) where the quality of the visualization is measured in the original data space instead of the projected space. Second, a version of the traveling salesperson problem (TSP) with the squared Euclidean distance metric; this distance metric allows the factorization of the data matrix, a key component for using GS. Third, a method for generating random data with designated distribution and correlation to an accuracy surpassing traditional techniques.

This project investigates the development of four different proofs of the law of quadratic reciprocity, in order to study the critical reasoning process that drives discovery in mathematics. We begin with an examination of the first proof of this law given by Gauss. We then describe Gauss’ fourth proof of this law based on Gauss sums, followed by a look at Eisenstein’s geometric simplification of Gauss’ third proof. Finally, we finish with an examination of one of the modern proofs of this theorem published in 1991 by Rousseau. Through this investigation we aim to analyze the different strategies used in the development of each of these proofs, and in the process gain a better understanding of this theorem.

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