Discrete Geometry
Mostrando 13-24 de 46 artigos, teses e dissertações.
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13. Codigos esfericos em toros planares / Spherical codes on flat torus
Spherical codes in Euclidean spaces are finite sets of points on the surface of a multidimensional sphere and have been widely studied in connection with the signal transmission over a Gaussian channel. For this purpose one fundamental issue is to maximize the minimum distance between two code points, what is strongly related to the more general problem of s
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/07/2009
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14. Hybrid motion planning approach for robot dexterous hands
This paper presents a manipulation planning approach for robot hands that enables the generation of finger trajectories. The planner is based on a hybrid approach that combines discrete-continuous kinematics using a fully discrete transition system. One of the main contributions of this work consists in the representation of the universe of different submode
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2009-12
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15. The density of lattice sphere packings / A densidade de empacotamentos esfericos em reticulados
This dissertation addresses the lattice theory with focus on packing density, which has many applications and allows to establish interesting connections between topics of linear algebra, calculus of several variables and discrete geometry. The first chapter is an introduction to the main concepts and properties of lattices. In the second chapter we discuss
Publicado em: 2009
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16. Reconstrução intranodal da solução numérica gerada pelo método espectronodal constante para problemas Sn de autovalor em geometria retangular bidimensional / Nodal reconstruction scheme for the numerical solution generated by the constant spectral nodal method for Sn eingenvalue problem in X, Y geometry
In this dissertation the spectral nodal method SD-SGF-CN, cf. spectral diamond spectral Green s function - constant nodal, is used to determine the angular fluxes averaged along the edges of the homogenized nodes in heterogeneous domains. Using these results, we developed an algorithm for the reconstruction of the node-edge average angular fluxes within the
Publicado em: 2009
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17. Convective cooling of three discrete heat sources in channel flow
A numerical investigation was performed to evaluate distinct convective heat transfer coefficients for three discrete strip heat sources flush mounted to a wall of a parallel plates channel. Uniform heat flux was considered along each heat source, but the remaining channel surfaces were assumed adiabatic. A laminar airflow with constant properties was forced
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2008-09
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18. Radiative transfer model for regular and discontinuous canopies (GRART): application in tree coffee canopies / Modelo de transferência radiativa para dosséis descontínuos regulares (GRART): aplicação para dosséis de café
Regularly displaced discontinuous plant stands such as coffee tree stands, citrus orchards, eucalyptus forests and annual crops at the beginning of their phenological cycle (row structured) are known as highly anisotropic remote sensing targets. Operational parameter estimate upon this kind of remote sensing targets requires a physically-based canopy reflect
Publicado em: 2008
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19. STATISTICAL OPTIMIZATION OF SPATIAL HIERARCHICAL STRUCTURES SEARCHS / OTIMIZAÇÃO ESTATÍSTICA DE BUSCAS PARA ESTRUTURAS HIERÁRQUICAS ESPACIAIS
This work emerged from the following observation: usual search procedures for 2d-trees start from the root to retrieve the data stored at the leaves. But since the leaves are the farthest nodes to the root, why start from the root? With usual 2d-trees representations, there is no other way to access a leaf. However, there exist 2d-trees which allow accessing
Publicado em: 2008
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20. Discrete Geometry and Codes / Geometria discreta e codigos
The research developed here is related and inspired by problems in coding theory. It is presented in two parts. In the first we focus on the search for the minimum nonvanishing vector of a lattice, specially in the case of a projection of the ndimensional integer lattice in the direction of one of its vectors. This is a problem of high computational complexi
Publicado em: 2007
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21. Discrete Geometry and Codes / Geometria discreta e codigos
The research developed here is related and inspired by problems in coding theory. It is presented in two parts. In the ?rst we focus on the search for the minimum nonvanishing vector of a lattice, specially in the case of a projection of the ndimensional integer lattice in the direction of one of its vectors. This is a problem of high computational complexit
Publicado em: 2007
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22. DISTRIBUIÇÕES E IMERSÕES / DISTRIBUTIONS AND IMMERSIONS
Os desafios de estudar formas levaram matemáticos a criar abstrações, em particular através da geometria diferencial. Porém, formas simples como cubos não se adequam a ferramentas diferenciáveis. Este trabalho é uma tentativa de usar avanços recentes da análise, no caso a teoria das distribuições, para estender quantidades diferenciáveis a objet
Publicado em: 2007
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23. Hyper-redundant robots with modules of parallel arquitecture. / Robô hiper-redundante com módulos de arquitetura paralela.
This research studies hyper-redundant robots focusing on the kinematics analysis. A hyper-redundant robot was developed based on modules of parallel architecture and binary actuators. Each module has three degrees-of-freedom, two rotational degrees of freedom with perpendicular axis and one translational degree of freedom. After searching for parallel struct
Publicado em: 2007
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24. Desenvolvimento de um método nodal analítico para problemas de ordenadas discretas em geometrias cartesianas bimdimensional e tridimensional em domínios homogêneos e heterogêneos / Development of an analytical nodal method for discrete ordinates problems in multidimensional cartesian geometry in homogeneous and heterogeneous media
Neste trabalho estendemos o método LTSN2D-DiagExp para problemas de transporte de nêutrons bidimensionais heterogêneos e construímos um novo algoritmo para resolver as equações de ordenadas discretas SN tridimensionais em domínios homogêneos e heterogêneos, denominado LTSN3D-DiagExp. Esses algoritmos são construídos a partir da diagonalização da
Publicado em: 2007