Linear Codes
Mostrando 13-24 de 73 artigos, teses e dissertações.
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13. Controle de atitude de satélites artificiais utilizando um processador digital de sinais / Attitude control of satellites using a digital signal processor
This work deals with the development and implementation of an attitude control system for an artificial satellite using a Digital Signal Processor (DSP). The dissertation presents a complete study of the attitude movement modeling and control for the continuous time systems case, considering the Linear Quadratic Regulator (LQR) and Linear Quadratic Gaussian
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/09/2010
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14. Matrizes de conexão para as dinamicas continua e discreta / Connectiion matrices for the continuous and discrete dynamics
The goal of this work is to present the connection matrix by establishing a parallel between the continuous and discrete settings. The homological Conley index, the main element in the definition of the connection matrix, has a diferent form for flows or continuous maps. This index is a graded vector space in the continuous case whereas in the discrete case
Publicado em: 2010
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15. Modelo de sistema de comunicações digital para o mecanismo de importação de proteinas mitocondriais atraves de codigos corretores de erros / Digital communication system model for mitochondrial protein import by use of error-correcting codes
One of the puzzling problems in mathematical biology is to show the existence of any form of error-correcting code in the DNA structure. Using information theory considerations we propose a model for the biological coding system similar to that of a digital communication system. This model consists of a mapper (transformations from the set of nucleotides eit
Publicado em: 2010
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16. A fatigue life prediction model of welded joints under combined cyclic loading. / Um modelo para previsão de vida à fadiga de juntas soldadas submetidas a carregamentos combinados.
The main purpose of this work is to develop a practical and robust methodology to evaluate the fatigue life in seam weld joints fabricated with GMAW process when subjected to combine cyclic loading. The maximum linear stress at the typical crack initiation region, better known as hot spot stress, was used to calculate the fatigue life through high cycle fati
Publicado em: 2010
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17. Algoritmos de autenticação de mensagens para redes de sensores. / Message authentication algorithms for wireless sensor networks.
Security is an important concern in any modern network. However, networks that are highly dependent on constrained devices (such as sensors, tokens and smart cards) impose a difficult challenge: their reduced availability of memory, processing power and (specially) energy hinders the deployment of many modern cryptographic algorithms known to be secure. This
Publicado em: 2010
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18. 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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19. Construction of linear block codes via digital transforms / ConstruÃÃo de cÃdigos de bloco lineares via transformadas digitais
Novas famÃlias de cÃdigos corretores de erros, criados a partir da transformada numÃrica de Fourier (CÃdigos de Fourier) e de transformadas trigonomÃtricas sobre corpos finitos (CÃdigos FFCT tipo 4 par, do inglÃs finite field cosine transform, e CÃdigos FFST tipo 4 par, do inglÃs finite field sine transform), sÃo apresentadas nesta dissertaÃÃo. A
Publicado em: 2009
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20. A contribution to the study of linear programming / Uma contribuiÃÃo ao estudo da programaÃÃo linear
The Linear Programming is quite useful to obtain optimal solutions for problems related to several areas of science, such as, industrial engineering, food industry, health science, mining, transport, among others. This work makes a review about linear programming, producing a didactic-scientific text that presents a consistent theoretical base of the main co
Publicado em: 2008
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21. Modelagem da propagação não linear em fibras opticas : sistemas de transmissão de dados e amplificadores / Modeling non linear propagation in optical fibers : data transmission systems and optical parametric amplifiers
We introduce optimized models and algorithms for the simulation of non linear propagation in optical fibers using the split-step Fourier Method (SSFM). Dispersion and the Kerr effect are the two main effects considered in the simulations. We study the coupled equations, considering both polarization modes, as well as the scalar equation, which can be applied
Publicado em: 2008
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22. Regime não-linear de trens de ondas modulados na direção transversal em um escoamento de Poiseuille plano / The nonlinear regime of spanwise modulated wavetrains in a plane Poiseuille flow
The current thesis had three objectives. The first objective was to develop a code of direct numerical simulation (DNS) to simulation of waves of instability in a plane Poiseuille flow. The other main objective was to analyze it through the method of manufactured solutions (MMS). Finally, a third objective was to study the nonlinear regime of spanwise modula
Publicado em: 2008
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23. From binary codes to lattices and spherical codes / De codigos binarios a reticulados e codigos esfericos
In this work it is presented through examples a connection between inary codes, lattices and spherical codes. A brief introduction to coding theory, properties and examples is included in the first chapter. In Chapter 2 lattices are approached with focus on the quotient of lattices, graphs on flat tori and connections with circulant graphs. An introduction t
Publicado em: 2007
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24. Codigos ciclicos sobre aneis locais e suas relações com a transformada discreta de Fourier / Cyclics codes on local rings and its relations with the discrete transformed of Fourier
In this research we present some existing relationships between cyclic codes and discrete Fourier transform both local rings. For this, it is necessary to identify the groups of unit associated with each corresponding local ring. As a consequence, cyclic codes over these rings may be constructed. Next, we construct sequence generators by use of linear feedba
Publicado em: 2007