Orthogonality
Mostrando 1-12 de 18 artigos, teses e dissertações.
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1. Sistemas CDMA ópticos coerentes baseados em codificação de fase espectral / Coherent optical CDMA systems based on spectral phase coding
In this work we perform a comprehensive analysis of a spectral phase-encoded time spreading optical code division multiple access (SPECTS-OCDMA) system. Despite being a numerical study, efforts were concentrated on the investigation of more realistic scenarios using as much information as possible from implemented test-beds in laboratories. In this context,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/12/2012
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2. A Common-Feature Approach for Testing Present-Value Restrictions with Financial Data
It is well known that cointegration between the level of two variables (labeled Yt and yt in this paper) is a necessary condition to assess the empirical validity of a present-value model (PV and PVM, respectively, hereafter) linking them. The work on cointegration has been so prevalent that it is often overlooked that another necessary condition for the PVM
Escola de Pós-Graduação em Economia da FGV. Publicado em: 24/02/2012
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3. Orthogonality and the hausdorff dimension of the maximal measure
In this paper the orthogonality properties of iterated polynomials are shown to remain valid in some cases for rational maps. Using a functional equation fulfilled by the generating function, the author shows that the Hausdorff dimension of the maximal measure is a real analytical function of the coefficients of an Axiom A rational map satisfying the propert
Publicado em: 2011
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4. Estimação de canais MIMO variantes no tempo usando filtros de Kalman / Time-varying MIMO channel estimation using Kalman filters
In this work we use Kalman filters to estimate time-varying wireless channels in multiple-input, multiple-output (MIMO) systems. First, we propose an optimal estimator (in the minimum mean squared error sense) to track flat channels in orthogonal space-time block coded systems. Due to the orthogonality inherent to these codes, the Kalman filter equations can
Publicado em: 2009
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5. An adaptive mesh strategy for high compressible flows based on nodal re-allocation
An adaptive mesh strategy based on nodal re-allocation is presented in this work. This technique is applied to problems involving compressible flows with strong shocks waves, improving the accuracy and efficiency of the numerical solution. The initial mesh is continuously adapted during the solution process keeping, as much as possible, mesh smoothness and l
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2008-09
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6. Mineração de padrões frequentes ortogonais e sua aplicação em classificação associativa
Frequent pattern mining is one of the most exploited subjects in data mining, assuming a key role in numerous tasks that have the goal of finding patterns of interest in a given data set. However, most of the solutions proposed in this line of research still have not solved problems, many of them related to the explosion in the number of frequent patterns fo
Publicado em: 2008
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7. Foundations of Hasse diagram and its applications on experimentation / Fundamentos do diagrama de Hasse e aplicações à experimentação
A crescente aplicação da estatística às mais diversas áreas de pesquisa, tem definido delineamentos complexos, dificultando assim seu planejamento e análise. O diagrama de Hasse é uma ferramenta gráfica, que tem como objetivo facilitar a compreensão da estrutura presente entre os fatores experimentais. Além de uma melhor visualização do experimen
Publicado em: 2008
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8. Grid generation and adaptation by functionals
Accuracy of a simulation is strongly depend on the grid quality. Here, quality means orthogonality at the boundaries and quasi-orthogonality within the critical regions, smoothness, bounded aspect ratios, solution adaptive behavior, etc. We review various functionals for generating high quality structured quadrilateral meshes in two dimensional domains. Anal
Computational & Applied Mathematics. Publicado em: 2007
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9. Uma contribuição ao método de síntese modal experimetal / A contribution for the experimental modal synthesis method
The determination of the dynamic parameters of great or complex structures can be made using modal synthesis methods subdividing the complete structure in substructures. The employment of this method may be done by using analytical or experimental procedures. Generally speaking, poor eigenvalues and eigenvectors may be identified using experimental modal syn
Publicado em: 2006
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10. A realization of the q-deformed harmonic oscillator: rogers-Szegö and Stieltjes-Wigert polynomials
We discuss some results from q-series that can account for the foundations for the introduction of orthogonal polynomials on the circle and on the line, namely the Rogers-Szegö and Stieltjes-Wigert polynomials. These polynomials are explicitly written and their orthogonality is verified. Explicit realizations of the raising and lowering operators for these
Brazilian Journal of Physics. Publicado em: 2003-03
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11. Performance Analisys of Multicarrier Systems in Peak Clipping Channels / Análise de Desempenho de Sistemas Multiportadora em Canais com Ceifamento de Pico
The advent of Digital Television brought a new scenario to the digital telecommunication systems, presenting new problems and challenges to be efficiently solved. Today, there are three different standards for Digital Television available: the ATSC developed in USA, DVB-T developed in Europe and ISDB-T developed in Japan. Two of these standards use a transmi
Publicado em: 2003
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12. MULTIUSER RECEIVERS WITH OPTIMAL GROUP DETECTION FOR CODE-DIVISION MULTIPLE-ACCESS CHANNELS / RECEPÇÃO MULTIUSUÁRIO COM DETECÇÃO ÓTIMA POR GRUPOS EM SISTEMAS COM MÚLTIPLO ACESSO CDMA
The most discussed multiple access techiniques for the 3G of mobile wireless systems involve some form of CDMA - Code Division Multiple Access- where the users can transmit simultaneously their signals in the same frequency band separable in the receiver by the orthogonality or, quasi- orthogonality, properties of the transmitted signals. Multiuser detectors
Publicado em: 2002