University, Diss., 2005--Kiel.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. / Made available in DSpace on 2012-10-19T02:17:40Z (GMT). No. of bitstreams: 0Bitstream added on 2016-01-09T03:36:56Z : No. of bitstreams: 1 175354.pdf: 2174314 bytes, checksum: 3d934ab8e79f01772de6e45634702fe3 (MD5) / As estruturas de Álgebra Exterior e Álgebra de Clifford se relacionam por isomorfismo de espaço vetorial. Se a forma quadrática é degenerada, a Álgebra de Clifford é a própria Álgebra Exterior para esse espaço. Construção de uma álgebra C/Q, onde Q é a forma quadrática para um espaço vetorial V como imagem de um operador alternado, definindo sobre tal álgebra um produto, de tal maneira que seja isomorfa à Álgebra de Clifford para V.

Universiẗat, Diss., 1997--Kaiserslautern.

This thesis comes in three main parts. In the first of these (comprising chapters 2 - 6), the basic theory of Riemannian and conformal submersions is described and the relevant geometric machinery explained. The necessary Clifford algebra is established and applied to understand the relationship between the spinor bundles of the base, the fibres and the total space of a submersion. O'Neill-type formulae relating the covariant derivatives of spinor fields on the base and fibres to the corresponding spinor field on the total space are derived. From these, formulae for the Dirac operators are obtained and applied to prove results on Dirac morphisms in cases so far unpublished. The second part (comprising chapters 7-9) contains the basic theory and known classifications of G2-structures and Spin+ 7 -structures in seven and eight dimensions. Formulae relating the covariant derivatives of the canonical forms and spinor fields are derived in each case. These are used to confirm the expected result that the form and spinorial classifications coincide. The mean curvature vector of associative and Cayley submanifolds of these spaces is calculated in terms of naturally-occurring tensor fields given by the structures. The final part of the thesis (comprising chapter 10) is an attempt to unify the first two parts. A certain `7-complex' quotient is described, which is analogous to the well-known hyper-Kahler quotient construction. This leads to insight into other possible interesting quotients which are correspondingly analogous to quaternionic-Kahler quotients, and these are speculated upon with a view to further research.

The goal of this thesis is the development of a fast and robust algorithm that is able to detect patterns in flow fields independent from their orientation and adequately visualize the results for a human user. This thesis is an interdisciplinary work in the field of vector field visualization and the field of pattern recognition. A vector field can be best imagined as an area or a volume containing a lot of arrows. The direction of the arrow describes the direction of a flow or force at the point where it starts and the length its velocity or strength. This builds a bridge to vector field visualization, because drawing these arrows is one of the fundamental techniques to illustrate a vector field. The main challenge of vector field visualization is to decide which of them should be drawn. If you do not draw enough arrows, you may miss the feature you are interested in. If you draw too many arrows, your image will be black all over. We assume that the user is interested in a certain feature of the vector field: a certain pattern. To prevent clutter and occlusion of the interesting parts, we first look for this pattern and then apply a visualization that emphasizes its occurrences. In general, the user wants to find all instances of the interesting pattern, no matter if they are smaller or bigger, weaker or stronger or oriented in some other direction than his reference input pattern. But looking for all these transformed versions would take far too long. That is why, we look for an algorithm that detects the occurrences of the pattern independent from these transformations. In the second part of this thesis, we work with moment invariants. Moments are the projections of a function to a function space basis. In order to compare the functions, it is sufficient to compare their moments. Normalization is the act of transforming a function into a predefined standard position. Moment invariants are characteristic numbers like fingerprints that are constructed from moments and do not change under certain transformations. They can be produced by normalization, because if all the functions are in one standard position, their prior position has no influence on their normalized moments. With this technique, we were able to solve the pattern detection task for 2D and 3D flow fields by mathematically proving the invariance of the moments with respect to translation, rotation, and scaling. In practical applications, this invariance is disturbed by the discretization. We applied our method to several analytic and real world data sets and showed that it works on discrete fields in a robust way.

Made available in DSpace on 2015-09-25T12:18:11Z (GMT). No. of bitstreams: 1 Leonardo Diego Lins.pdf: 998692 bytes, checksum: fc07616f62603f53cdf45368f9743730 (MD5) Previous issue date: 2010-10-14 / The role of physics education in the advancement of scientific and technological knowledge in our society is paramount. In Brazil, this teaching is recognized as inadequate both in regard to training students and professors translated into weak learning of physical concepts and mathematical apparatus. In general it is characterized by excessive attention given the repetitive exercises, problems solved, mechanically, by using a succession of "formulas" are often decorated literal and arbitrary, rather than a deeper analysis in order to understand the physical phenomena involved. Particularly, we wish to emphasize that a major problem has been the inappropriate use of mathematical tools and disconnected from the formulation and use of physical concepts. This creates a conceptual mathematical-physical dichotomy that undermines the understanding of the profound connection between these two sciences. Considering these problems of mathematical order in the learning process of physical concepts, this research aims to constructive criticism from the language used in mathematical physics, to introduce a methodological approach physical-mathematical concept using the core concepts of dynamics. This means that as we present a mathematical concept suitable for their representation. We chose the Clifford algebra as the mathematical language appropriate to this approach physical-mathematical concepts. The operationalization of the teaching content is baptized by the cognitive model Subsumption. We understand that it is more adaptable to the design of courseware in science, therefore, allows the exploration of a hierarchical cognitive universe of the learner but also allows for the deliberate manipulation of this universe to provide a meaningful learning. / O papel desempenhado pelo ensino de física no avanço do conhecimento científico e tecnológico na nossa sociedade é de suma importância. No Brasil esse ensino é reconhecido como deficiente tanto no que se refere à formação docente como discente traduzido na débil aprendizagem dos conceitos físicos e do aparato matemático. De maneira geral ele é caracterizado pelo excesso de atenção dada a exercícios repetitivos, problemas resolvidos, mecanicamente, pela utilização de uma sucessão de fórmulas , muitas vezes decoradas de forma literal e arbitrária, em detrimento de uma análise mais profunda visando à compreensão dos fenômenos físicos envolvidos. Particularmente, gostaríamos de destacar que um grave problema tem sido o uso inadequado e desvinculado do ferramental matemático com relação à formulação e uso dos conceitos físicos. Isso gera uma dicotomia conceitual físico-matemática que prejudica a compreensão da profunda conexão entre estas duas ciências. Tendo em vista esses problemas de ordem matemática no processo de aprendizagem dos conceitos físicos, esta pesquisa pretende partir da crítica construtiva da linguagem matemática usada em física, introduzir uma abordagem metodológica físico-matemática conceitual utilizando os principais conceitos da dinâmica. Isto significa que ao apresentarmos um conceito matemático adequado a sua representação. Escolhemos a álgebra de Clifford como a linguagem matemática apropriada a esta abordagem físico-matemática conceitual. A operacionalização didática dos conteúdos é batizada pelo modelo cognitivista ausubeliano. Entendemos que o mesmo é o mais adaptável à concepção de material didático em ciências, pois, permite a exploração de forma hierárquica do universo cognitivo do aprendiz como também possibilita a manipulação deliberada deste universo para propiciar uma aprendizagem significativa.

Made available in DSpace on 2015-09-25T12:18:15Z (GMT). No. of bitstreams: 1 Humberto Jose Gama da Silva_1.pdf: 1171637 bytes, checksum: 8d18e9a9faa7cc4da00a9873103a9498 (MD5) Previous issue date: 2010-12-17 / The process of teaching learning Physics, in Brazil, has been recognized as deficient in several studies. Particularly, we note that one of the problems has been the mathematical framework regarding the use of physical concepts. This problem seems to generate a conceptual mathematical physical dichotomy which affects the understanding and assimilation of the deep connections between Physics and Mathematics. The aim of this work was to present an exploratory study that evaluated according to the findings by means of the data collection the feasibility of using Clifford Algebra as a formalism adapted to the study of electromagnetism in high school level, specifically obtaining the characteristics of the magnetic force vector which acts on electric charges or electrical currents within a magnetic field. Therefore, it was carried out two interventions at different dates. The first one was done in Campina Grande - PB, at the Dean of Graduate Studies and Research University of Paraiba, UEPB. The second was done in Imperatriz MA, at the Federal institute of education science and technology IFMA. Both intervention had as public target students, teachers and future teachers of physics for high school level. Motivated by the characteristics of objectivity and serviceability of Ausubel‟s cognitive theory, its foundations were used for developing a potentially significant material developed by the selection and reading of literary criticism about Vector Algebra and Geometry. The same foundations were also used as an adjunct in the learning process content covered in the interventions and subsumers in identifying the content being addressed, the use of conceptual maps as facilitative technique in the expositions of topics and as evaluation tool. At those intersections was pointed out that the formalism of Gibbs still has predominance in the textbooks adopted in at secondary and high education levels, even prompting the students to use it in the mathematical treatment directed to the study of physical measures memorizing precepts not justified , like rule of right hand. However, the structure or the Clifford Algebra enables a more intuitive mathematical modeling which is characterized by the representation and manipulation of basic geometric concepts such as magnitude, direction and meaning. / O processo ensino aprendizagem da Física, no Brasil, tem sido reconhecido como deficiente em diversos estudos. Particularmente, gostaríamos de destacar que um dos problemas tem sido o ferramental matemático com relação ao uso dos conceitos físicos. Este problema parece gerar uma dicotomia conceitual físico-matemática que prejudica a compreensão e assimilação das profundas conexões entre a Física e a Matemática. O objetivo desse trabalho é apresentar um estudo exploratório em que foi avaliada de acordo com os resultados obtidos através de instrumentos de coleta de dados a viabilidade do uso da Álgebra de Clifford como um formalismo adaptável para o estudo do Eletromagnetismo no Ensino Médio, especificamente na obtenção das características do vetor Força Magnética que atua em cargas elétricas em movimento ou em correntes elétricas dentro de um campo magnético. Para tanto foram feitas duas intervenções, em datas distintas. A primeira foi realizada em Campina Grande PB, na Pró-Reitoria de PósGraduação e Pesquisa da Universidade Estadual da Paraíba UEPB. A segunda foi realizada em Imperatriz MA, no Instituto Federal de Educação Ciência e Tecnologia IFMA. Os dois eventos tiveram como público alvo alunos, professores e futuros professores de Física do Ensino Médio. Motivado pelas características de objetividade e operacionalidade da Teoria Cognitivista de Ausubel, seus fundamentos foram utilizados na elaboração de um material potencialmente significativo desenvolvido a partir da seleção e leitura crítica da produção literária acerca das Álgebras Vetorial e Geométrica usando como coadjuvante no processo ensino-aprendizagem dos conteúdos contemplados nas intervenções. Os mesmos fundamentos também foram utilizados na identificação dos subsunçores do conteúdo a ser abordado, no uso de Mapas Conceituais como técnica facilitadora na exposição dos tópicos e como instrumento de avaliação. Nas referidas intercessões foi apontado que o formalismo de Gibbs ainda exerce predominância nos livros textos adotados no Ensino Médio e Superior, mesmo induzindo os alunos a utilizarem, no tratamento matemático direcionado ao estudo das grandezas físicas, preceitos de memorização, não justificados, como a regra da mão direita. Entretanto, a estrutura da Álgebra de Clifford permite uma modelagem matemática mais intuitiva, que tem como característica a representação e manipulação de conceitos geométricos básicos, tais como magnitude, direção e sentido.

Made available in DSpace on 2015-09-25T12:22:04Z (GMT). No. of bitstreams: 1 PDF - Humberto Jose Gama da Silva.pdf: 2786114 bytes, checksum: 1c9f2c90d2847243c55b7a607880924f (MD5) Previous issue date: 2010-12-17 / The process of teaching learning Physics, in Brazil, has been recognized as deficient in several studies. Particularly, we note that one of the problems has been the mathematical framework regarding the use of physical concepts. This problem seems to generate a conceptual mathematical physical dichotomy which affects the understanding and assimilation of the deep connections between Physics and Mathematics. The aim of this work was to present an exploratory study that evaluated according to the findings by means of the data collection the feasibility of using Clifford Algebra as a formalism adapted to the study of electromagnetism in high school level, specifically obtaining the characteristics of the magnetic force vector which acts on electric charges or electrical currents within a magnetic field. Therefore, it was carried out two interventions at different dates. The first one was done in Campina Grande - PB, at the Dean of Graduate Studies and Research University of Paraiba, UEPB. The second was done in Imperatriz MA, at the Federal institute of education science and technology IFMA. Both intervention had as public target students, teachers and future teachers of physics for high school level. Motivated by the characteristics of objectivity and serviceability of Ausubel‟s cognitive theory, its foundations were used for developing a potentially significant material developed by the selection and reading of literary criticism about Vector Algebra and Geometry. The same foundations were also used as an adjunct in the learning process content covered in the interventions and subsumers in identifying the content being addressed, the use of conceptual maps as facilitative technique in the expositions of topics and as evaluation tool. At those intersections was pointed out that the formalism of Gibbs still has predominance in the textbooks adopted in at secondary and high education levels, even prompting the students to use it in the mathematical treatment directed to the study of physical measures memorizing precepts not justified , like rule of right hand. However, the structure or the Clifford Algebra enables a more intuitive mathematical modeling which is characterized by the representation and manipulation of basic geometric concepts such as magnitude, direction and meaning. / O processo ensino aprendizagem da Física, no Brasil, tem sido reconhecido como deficiente em diversos estudos. Particularmente, gostaríamos de destacar que um dos problemas tem sido o ferramental matemático com relação ao uso dos conceitos físicos. Este problema parece gerar uma dicotomia conceitual físico-matemática que prejudica a compreensão e assimilação das profundas conexões entre a Física e a Matemática. O objetivo desse trabalho é apresentar um estudo exploratório em que foi avaliada de acordo com os resultados obtidos através de instrumentos de coleta de dados a viabilidade do uso da Álgebra de Clifford como um formalismo adaptável para o estudo do Eletromagnetismo no Ensino Médio, especificamente na obtenção das características do vetor Força Magnética que atua em cargas elétricas em movimento ou em correntes elétricas dentro de um campo magnético. Para tanto foram feitas duas intervenções, em datas distintas. A primeira foi realizada em Campina Grande PB, na Pró-Reitoria de PósGraduação e Pesquisa da Universidade Estadual da Paraíba UEPB. A segunda foi realizada em Imperatriz MA, no Instituto Federal de Educação Ciência e Tecnologia IFMA. Os dois eventos tiveram como público alvo alunos, professores e futuros professores de Física do Ensino Médio. Motivado pelas características de objetividade e operacionalidade da Teoria Cognitivista de Ausubel, seus fundamentos foram utilizados na elaboração de um material potencialmente significativo desenvolvido a partir da seleção e leitura crítica da produção literária acerca das Álgebras Vetorial e Geométrica usando como coadjuvante no processo ensino-aprendizagem dos conteúdos contemplados nas intervenções. Os mesmos fundamentos também foram utilizados na identificação dos subsunçores do conteúdo a ser abordado, no uso de Mapas Conceituais como técnica facilitadora na exposição dos tópicos e como instrumento de avaliação. Nas referidas intercessões foi apontado que o formalismo de Gibbs ainda exerce predominância nos livros textos adotados no Ensino Médio e Superior, mesmo induzindo os alunos a utilizarem, no tratamento matemático direcionado ao estudo das grandezas físicas, preceitos de memorização, não justificados, como a regra da mão direita. Entretanto, a estrutura da Álgebra de Clifford permite uma modelagem matemática mais intuitiva, que tem como característica a representação e manipulação de conceitos geométricos básicos, tais como magnitude, direção e sentido.

The goal of this thesis is the development of a fast and robust algorithm that is able to detect patterns in flow fields independent from their orientation and adequately visualize the results for a human user. This thesis is an interdisciplinary work in the field of vector field visualization and the field of pattern recognition. A vector field can be best imagined as an area or a volume containing a lot of arrows. The direction of the arrow describes the direction of a flow or force at the point where it starts and the length its velocity or strength. This builds a bridge to vector field visualization, because drawing these arrows is one of the fundamental techniques to illustrate a vector field. The main challenge of vector field visualization is to decide which of them should be drawn. If you do not draw enough arrows, you may miss the feature you are interested in. If you draw too many arrows, your image will be black all over. We assume that the user is interested in a certain feature of the vector field: a certain pattern. To prevent clutter and occlusion of the interesting parts, we first look for this pattern and then apply a visualization that emphasizes its occurrences. In general, the user wants to find all instances of the interesting pattern, no matter if they are smaller or bigger, weaker or stronger or oriented in some other direction than his reference input pattern. But looking for all these transformed versions would take far too long. That is why, we look for an algorithm that detects the occurrences of the pattern independent from these transformations. In the second part of this thesis, we work with moment invariants. Moments are the projections of a function to a function space basis. In order to compare the functions, it is sufficient to compare their moments. Normalization is the act of transforming a function into a predefined standard position. Moment invariants are characteristic numbers like fingerprints that are constructed from moments and do not change under certain transformations. They can be produced by normalization, because if all the functions are in one standard position, their prior position has no influence on their normalized moments. With this technique, we were able to solve the pattern detection task for 2D and 3D flow fields by mathematically proving the invariance of the moments with respect to translation, rotation, and scaling. In practical applications, this invariance is disturbed by the discretization. We applied our method to several analytic and real world data sets and showed that it works on discrete fields in a robust way.

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-08-15T17:16:32Z No. of bitstreams: 1 PDF - Bruno Barros Camêlo.pdf: 1453825 bytes, checksum: 0c755892d9dbe76fb2ec46bbaa59aad2 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-08-17T15:30:31Z (GMT) No. of bitstreams: 1 PDF - Bruno Barros Camêlo.pdf: 1453825 bytes, checksum: 0c755892d9dbe76fb2ec46bbaa59aad2 (MD5) / Made available in DSpace on 2016-08-17T15:30:31Z (GMT). No. of bitstreams: 1 PDF - Bruno Barros Camêlo.pdf: 1453825 bytes, checksum: 0c755892d9dbe76fb2ec46bbaa59aad2 (MD5) Previous issue date: 2014-10-08 / In physics is very familiar employment of vectors. These can be seen, the geometric point of view, as straight segments oriented. However, certain quantities are better represented by other objects with geometrical features than with vectors. Such objects are represented by fragments of oriented planes, which cannot be determined by vectors, unless we are in three dimensional space. Geometric or Clifford algebra can be treated as a generalization of vector algebra, and consists of a powerful formalism for the physical description of nature. Thus, we propose in this work, to build strategies to introduce the Clifford algebra as modeler physical concepts of the Theory of Special Relativity and from the modeled concepts, develop educational material for teaching physics in the light of the conception of learning Ausubel. / Na Física é muito familiar o emprego de vetores. Estes podem ser vistos, pelo ponto de vista geométrico, como segmentos de reta orientados. No entanto, certas grandezas ficam mais bem representadas por outros objetos com características geométricas do que com os vetores. Tais objetos são representados por fragmentos de planos orientados, os quais não podem ser determinados por vetores, a menos que estejamos no espaço tridimensional. A álgebra geométrica ou de Clifford pode ser tratada como uma generalização da álgebra vetorial, e consiste em um poderoso formalismo para a descrição física da natureza. Assim, propomos nesse trabalho,construir estratégias para introduzir a álgebra de Clifford como modelador de conceitos físicos da Teoria da Relatividade Restrita à luz da concepção Ausubeliana da aprendizagem para organizar os conceitos dentro de um modelo cognitivo.