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The central object of the study in this thesis is ΩO(<I>n</I>), the space of closed continuous loops on an orthogonal group O(<I>n</I>) based at the identity-element 1 Ε O(<I>n</I>). The space ΩO(<I>n</I>) carries a group structure given by pointwise multiplication of paths in the group O(<I>n</I>). This makes it an infinite dimensional Lie group. A filtration of ΩO(<I>n</I>), more precisely of the subspace of 'polynomial' loops, is constructed. This can be thought of as the 'real' analogue of the Mitchell-Richter filtration of ΩSU(<I>n</I>). Our filtration of ΩO(<I>n</I>) splits stably and O(<I>n</I>)-equivariantly in the cases <I>n</I> = 3, 4. We obtain: In contrast to the complex case no general splitting result can hold (this follows from work by Hopkins on stable indecomposability of ΩSp(2)). The thesis also investigates the topology of the loopspace of a real Stiefel-manifold. A stable O(<I>n</I>)-equivariant splitting for the fibrewise loop-space of a projective bundle is used to give a splitting for the free loop-space LRP<I>ⁿ</I> on a real projective space.

The Kogut and Singh (1988) index is the most widely used construct to measure cultural distance in international business and management research. We show that this index is incorrectly specified and captures the squared cultural distance. This inaccuracy is problematic because it means that the empirical findings on the effects of cultural distance presented in different strands of international business research are likely to be misleading. We specify the correct form of the distance measure based on the Euclidean distance formula and demonstrate the implications of using the incorrectly specified Kogut and Singh (1988) index.

Let 1, 2, 3, 5, 8, … denote the Fibonacci sequence beginning with 1 and 2, and then setting each subsequent number to the sum of the two previous ones. Every positive integer n can be expressed as a sum of distinct Fibonacci numbers in one or more ways. Setting R(n) to be the number of ways n can be written as a sum of distinct Fibonacci numbers, we exhibit certain regularity properties of R(n), one of which is connected to the Euler φ-function. In addition, using a theorem of Fine and Wilf, we give a formula for R(n) in terms of binomial coefficients modulo two.

Made available in DSpace on 2014-06-11T19:24:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-08-31Bitstream added on 2014-06-13T19:11:45Z : No. of bitstreams: 1 gouvea_fr_me_rcla.pdf: 3114009 bytes, checksum: 7cfd768795cfd2d4315b640578fa631f (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Neste trabalho abordamos um tema pouco explorado nos cursos de graduação em Matemática, que é a Geometria Fractal, resgatando conceitos básicos da Geometria Euclidiana, utilizando caleidoscópios e softwares educacionais. Assim, foram tecidas algumas considerações a respeito da utilização de computadores na sala de aula, através de um estudo que investigou: Que contribuições pode trazer, para o ensinoaprendizagem de Geometria, um estudo de Fractais Geométricos através de caleidoscópios e softwares de Geometria Dinâmica ?. Foram elaboradas atividades e aplicadas a alunos da Licenciatura em Matemática (do 1º e 2º semestres) da Unesp de Rio Claro, que participaram de um Curso de Extensão. A utilização de materiais diferentes do tradicional, como o caleidoscópio e o computador (este último como elemento inserido no contexto educacional), e a contextualização da Geometria contribuíram para o estabelecimento de um ambiente de aprendizagem agradável e participativo. Nosso estudo mostrou uma maneira inovadora de obterem-se fractais geométricos: através de bases caleidoscópicas, o que enseja um grande estudo sobre espelhos e caleidoscópios, e traz em si a oportunidade de estudarem-se muitos conceitos geométricos (reflexão, simetrias, transformações geométricas, bissetriz, mediatriz, seqüências, etc.). Apresentamos, ainda, alguns aspectos pedagógicos e matemáticos relacionados à aplicabilidade dos Fractais Geométricos no processo de construção de conceitos geométricos, por meio da interação aluno-aluno, aluno-computador e alunoprofessor, tendo como pano de fundo a resolução de problemas. Dessa forma, nosso estudo proporcionou para os alunos uma maior relação com os conceitos fundamentais de Geometria Euclidiana e Geometria Fractal, além de uma alternativa metodológica inerente ao ensino da Geometria. / In this work we approached a theme little explored in the degree courses in Mathematics, that it is the Fractal Geometry ransoms basic concepts of the Euclidian Geometry, using kaleidoscopic and educational softwares. At his, are some woven considerations respect the use computers in the classroom, through a study that enquired: What contributions can bring, for teaching-learning of Geometry, a study of the geometrical fractals that include kaleidoscopic and softwares of Dynamic Geometry? Activities were elaborated and applied to students of the degree in mathematics (of the 1st and 2nd semesters) of Unesp de Rio Claro, who participated in a Course of Extension. The use of different materials from the traditional as the kaleidoscopic and computer (this last one as element inserted in the education context), and the contextualization of the Geometry contributed to the establishment of an environment of the pleasing learning and interest. Our study showed an innovator way of they be obtained fractal geometrics: through of kaleidoscopic bases, that wish a great study with mirrors and kaleidoscopic, and bring in itself the opportunity of they be studied many geometric concepts (reflection, symmetric, geometric transformations, bisector, mediate, etc). We presented, still, some pedagogic and mathematic aspects related to the applicability of Fractal Geometrics in the process of construction of geometrical concepts, through the interaction student-student, student-computer and student-teacher using as backdrop the problem solve. Of this form, our study it provided for the students a bigger relation with the basic concepts of Euclidean Geometry and Fractal Geometry, beyond inherent a metodology alternative to the teaching of Geometry.

Orientador: Claudemir Murari / Banca: Geraldo Perez / Banca: Ruy Madsen Barbosa / Resumo: Neste trabalho abordamos um tema pouco explorado nos cursos de graduação em Matemática, que é a Geometria Fractal, resgatando conceitos básicos da Geometria Euclidiana, utilizando caleidoscópios e softwares educacionais. Assim, foram tecidas algumas considerações a respeito da utilização de computadores na sala de aula, através de um estudo que investigou: "Que contribuições pode trazer, para o ensinoaprendizagem de Geometria, um estudo de Fractais Geométricos através de caleidoscópios e softwares de Geometria Dinâmica ?". Foram elaboradas atividades e aplicadas a alunos da Licenciatura em Matemática (do 1º e 2º semestres) da Unesp de Rio Claro, que participaram de um Curso de Extensão. A utilização de materiais diferentes do tradicional, como o caleidoscópio e o computador (este último como elemento inserido no contexto educacional), e a contextualização da Geometria contribuíram para o estabelecimento de um ambiente de aprendizagem agradável e participativo. Nosso estudo mostrou uma maneira inovadora de obterem-se fractais geométricos: através de bases caleidoscópicas, o que enseja um grande estudo sobre espelhos e caleidoscópios, e traz em si a oportunidade de estudarem-se muitos conceitos geométricos (reflexão, simetrias, transformações geométricas, bissetriz, mediatriz, seqüências, etc.). Apresentamos, ainda, alguns aspectos pedagógicos e matemáticos relacionados à aplicabilidade dos Fractais Geométricos no processo de construção de conceitos geométricos, por meio da interação aluno-aluno, aluno-computador e alunoprofessor, tendo como pano de fundo a resolução de problemas. Dessa forma, nosso estudo proporcionou para os alunos uma maior relação com os conceitos fundamentais de Geometria Euclidiana e Geometria Fractal, além de uma alternativa metodológica inerente ao ensino da Geometria. / Abstract: In this work we approached a theme little explored in the degree courses in Mathematics, that it is the Fractal Geometry ransoms basic concepts of the Euclidian Geometry, using kaleidoscopic and educational softwares. At his, are some woven considerations respect the use computers in the classroom, through a study that enquired: "What contributions can bring, for teaching-learning of Geometry, a study of the geometrical fractals that include kaleidoscopic and softwares of Dynamic Geometry?" Activities were elaborated and applied to students of the degree in mathematics (of the 1st and 2nd semesters) of Unesp de Rio Claro, who participated in a Course of Extension. The use of different materials from the traditional as the kaleidoscopic and computer (this last one as element inserted in the education context), and the contextualization of the Geometry contributed to the establishment of an environment of the pleasing learning and interest. Our study showed an innovator way of they be obtained fractal geometrics: through of kaleidoscopic bases, that wish a great study with mirrors and kaleidoscopic, and bring in itself the opportunity of they be studied many geometric concepts (reflection, symmetric, geometric transformations, bisector, mediate, etc). We presented, still, some pedagogic and mathematic aspects related to the applicability of Fractal Geometrics in the process of construction of geometrical concepts, through the interaction student-student, student-computer and student-teacher using as backdrop the problem solve. Of this form, our study it provided for the students a bigger relation with the basic concepts of Euclidean Geometry and Fractal Geometry, beyond inherent a metodology alternative to the teaching of Geometry. / Mestre

Cette thèse est consacrée à l'analyse de l'association de codes LDPC non-binaires (LDPC-NB) à des modulations d’ordre élevé. Cette association vise à améliorer l’efficacité spectrale pour les futurs systèmes de communication sans fil. Notre approche a consisté à tirer au maximum profit de l'association directe des symboles d’un code LDPC-NB sur un corps de Galois avec une constellation de même cardinalité. Notre première contribution concerne la diversité spatiale obtenue dans un canal de Rayleigh avec et sans effacement en faisant subir une rotation à la constellation. Nous proposons d’utiliser l'information mutuelle comme paramètre d’optimisation de l’angle de rotation, et ce pour les modulations de type « BICM » et les modulations codées. Cette étude permet de mettre en évidence les avantages de la modulation codée par rapport à la modulation BICM de l’état de l’art. Par simulation de Monte-Carlo, nous montrons que les gains de codage théoriques se retrouvent dans les systèmes pratiques. Notre deuxième contribution consiste à concevoir conjointement l'étiquetage des points de constellation et le choix des coefficients d'une équation de parité en fonction de la distance euclidienne, et non plus de la distance de Hamming. Une méthode d’optimisation est proposée. Les codes ainsi construits offrent des gains de performance de 0.2 dB et ce, sans ajout de complexité. / This thesis is devoted to the analysis of the association of non-binary LDPC codes (NB-LDPC) with high-order modulations. This association aims to improve the spectral efficiency of future wireless communication systems. Our approach tries to take maximum advantage of the straight association between NB-LDPC codes over a Galois Field with modulation constellations of the same cardinality. We first investigate the optimization of the signal space diversity technique obtained with the Rayleigh channel (with and without erasure) thanks to the rotation of the constellation. To optimize the rotation angle, the mutual information analysis is performed for both coded modulation (CM) and bit-interleaved coded modulation (BICM) schemes. The study shows the advantages of coded modulations over the state-of-the-art BCIM modulations. Using Monte Carlo simulation, we show that the theoretical gains translate into actual gains in practical systems. In the second part of the thesis, we propose to perform a joint optimization of constellation labeling and parity-check coefficient choice, based on the Euclidian distance instead of the Hamming distance. An optimization method is proposed. Using the optimized matrices, a gain of 0.2 dB in performance is obtained with no additional complexity.

This study aimed to investigate the level of understanding of Euclidian geometry, in terms of theoretical knowledge as well as its problem-solving application, in pre-service mathematics education (PME) students at the University of Pretoria. In order to do so, a one group pre-test/ post-test procedure was conducted around an intensive geometry module, and a representational group of students was interviewed before and after the module to discuss their high school experiences of learning geometry and to analyse their attitudes towards the subject. The van Hiele Theory of Levels of Thought in Geometry was used as the theoretical framework for this study. The PME students in this study, prior to their completion of the geometry module, lacked the content knowledge, skills and insight in Euclidian geometry that is expected at matric level (Level 3). The pre-test results revealed that half the group could only be classified as being on Level 0. By the time the post-test was written, 60% of the group had moved onto Level 1 as their maximum competence level. This implies that these students were all brought to greater insight by the teaching they received during the geometry module. However, the overall improvement in the group as revealed in the post-test results, consisted of an upward movement of only one level. Therefore, the geometry module offered did not bring about sufficient improvement for these students to be able to teach geometry adequately (Level 3 is required). The students who were interviewed for this study uniformly expressed their dislike or fear of Euclidian geometry in general, but described the positive change in their attitude during the course of the module because of the way it was presented. Training of students for a career as mathematics educators which includes an in-depth van Hiele-based geometry module would facilitate the acquisition of insight and relational understanding. / Dissertation (MEd)--University of Pretoria, 2008. / Curriculum Studies / MEd / unrestricted

Com base em exames como a videolaringoscopia, que é considerado um procedimento médico invasivo e desconfortável, diagnósticos têmsido realizados visando detectar patologias na laringe. Geralmente, esse tipo de exame é realizado somente com solicitação médica e quando alterações na fala já são marcantes, ou há sensação de dor. Nessa fase, muitas vezes a doença está em grau avançado, dificultando o seu tratamento. Com o objetivo de realizar um pré-diagnóstico computacional de tais patologias, este trabalho apresenta uma técnica não invasiva na qual são testados e comparados três classificadores: a Distância Euclidiana, a Rede Neural RBF com o kernel Gaussiano e a Rede Neural RBF com o kernel Gaussiano modificado. Testes realizados com uma base de dados de vozes normais e aquelas afetadas por diversas patologias demonstram a eficácia da técnica proposta, que pode, inclusive, ser implementada em tempo-real. / Based on examinations such as laryngoscopy, which is considered an invasive and uncomfortable procedure, diagnosis have been performed aiming at the detection of larynx pathologies. Usually, this type of test is carried out upon medical request and when the speech changes are notable or are causing pain. At this point, the disease is possibly at an advanced degree, complicating its treatment. In order to perform a computational pre-diagnosis of such conditions, this work proposes a noninvasive technique in which three classifiers are tested and compared: the Euclidean distance, the RBF Neural Network with the Gaussian kernel and RBF Neural Network with a modified Gaussian kernel. Tests carried out with a database of normal voices and those affected by various pathologies demonstrate the effectiveness of the technique that may even be implemented to work in real time.

Este trabalho investiga a decodificação turbo de códigos produto construídos a partir de códigos de Reed-Solomon sobre constelações QAM. Por meio da geometria euclidiana da constelação utilizada e das relações dos elementos de campo de Galois utilizados na codificação Reed-Solomon com os símbolos pertencentes ao alfabeto de modulação, é proposto um algoritmo de decodificação que utiliza a localização geométrica dos símbolos recebidos no processo de decodificação turbo. Tanto a primeira etapa da decodificação SISO baseada no algoritmo de Chase, como a extração da informação extrínseca baseada no algoritmo proposto por Pyndiah, são tratadas pelo uso de uma abordagem geométrica sobre o espaço euclidiano. Os resultados de simulação utilizando o algoritmo proposto coincidem com aqueles usando a decomposição e análise pragmática binária, sendo que a abordagem apresentada conduz a simplificações e otimizações em relação à metodologia binária no que ser refere à implementação dos possíveis esquemas de decodificação. / This work investigates the turbo decoding of product codes built using Reed- Solomon codes in QAM constellations. Using the euclidian geometry of the constellation and the relations of the Galois field elements used in the Reed-Solomon code and the modulation alphabet, a decoding algorithm for the turbo decoding process is proposed using the geometric localization of the received symbol. Both the first stage of the SISO decoding based on the Chase algorithm, as the calculation of the extrinsic information based on the Pyndiah algorithm, are treated using the geometric approach in the euclidian space. The simulations show that this algorithm gives similar performance results as the pragmatic binary decomposition approach, and leads to simplifications and optimizations in decoding implementations schemes compared to the former.