Otimização de superfícies seletivas de frequência com elementos pré-fractais utilizando rede neural MLP e algoritmos de busca populacional

This thesis describes design methodologies for frequency selective surfaces (FSSs) composed of periodic arrays of pre-fractals metallic patches on single-layer dielectrics (FR4, RT/duroid). Shapes presented by Sierpinski island and T fractal geometries are exploited to the simple design of efficient band-stop spatial filters with applications in the range of microwaves. Initial results are discussed in terms of the electromagnetic effect resulting from the variation of parameters such as, fractal iteration number (or fractal level), fractal iteration factor, and periodicity of FSS, depending on the used pre-fractal element (Sierpinski island or T fractal). The transmission properties of these proposed periodic arrays are investigated through simulations performed by Ansoft DesignerTM and Ansoft HFSSTM commercial softwares that run full-wave methods. To validate the employed methodology, FSS prototypes are selected for fabrication and measurement. The obtained results point to interesting features for FSS spatial filters: compactness, with high values of frequency compression factor; as well as stable frequency responses at oblique incidence of plane waves. This thesis also approaches, as it main focus, the application of an alternative electromagnetic (EM) optimization technique for analysis and synthesis of FSSs with fractal motifs. In application examples of this technique, Vicsek and Sierpinski pre-fractal elements are used in the optimal design of FSS structures. Based on computational intelligence tools, the proposed technique overcomes the high computational cost associated to the full-wave parametric analyzes. To this end, fast and accurate multilayer perceptron (MLP) neural network models are developed using different parameters as design input variables. These neural network models aim to calculate the cost function in the iterations of population-based search algorithms. Continuous genetic algorithm (GA), particle swarm optimization (PSO), and bees algorithm (BA) are used for FSSs optimization with specific resonant frequency and bandwidth. The performance of these algorithms is compared in terms of computational cost and numerical convergence. Consistent results can be verified by the excellent agreement obtained between simulations and measurements related to FSS prototypes built with a given fractal iteration

Improved geometric parameterisation techniques for continuation power flow

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Testing the ecomorphological hypothesis in a headwater riffles fish assemblage of the rio São Francisco, southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Rapidly varying boundaries in equations with nonlinear boundary conditions. The case of a Lipschitz deformation

We analyze the behavior of solutions of nonlinear elliptic equations with nonlinear boundary conditions of type partial derivative u/partial derivative n + g( x, u) = 0 when the boundary of the domain varies very rapidly. We show that the limit boundary condition is given by partial derivative u/partial derivative n+gamma(x) g(x, u) = 0, where gamma(x) is a factor related to the oscillations of the boundary at point x. For the case where we have a Lipschitz deformation of the boundary,. is a bounded function and we show the convergence of the solutions in H-1 and C-alpha norms and the convergence of the eigenvalues and eigenfunctions of the linearization around the solutions. If, moreover, a solution of the limit problem is hyperbolic, then we show that the perturbed equation has one and only one solution nearby.

VERY RAPIDLY VARYING BOUNDARIES IN EQUATIONS WITH NONLINEAR BOUNDARY CONDITIONS. THE CASE of A NON UNIFORMLY LIPSCHITZ DEFORMATION

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A decentralized approach for optimal reactive power dispatch using a Lagrangian decomposition method

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Indexes of structural reform in Latin America

Includes bibliography

A C2-continuous high-resolution upwind convection scheme

A bounded upwinding scheme for numerical solution of hyperbolic conservation laws and Navier-Stokes equations is presented. The scheme is based on convection boundedness criterion and total variation diminishing stability criteria and developed by employing continuously differentiable functions. The accuracy of the scheme is verified by assessing the error and observed convergence rate on 1-D benchmark test cases. A comparative study between the new scheme and conventional total variation diminishing/convection boundedness criterion-based upwind schemes to solve standard nonlinear hyperbolic conservation laws is also accomplished. The scheme is then examined in the simulation of Newtonian and non-Newtonian fluid flows of increasing complexity; a satisfactory agreement has been observed in terms of the overall behavior. Finally, the scheme is used to study the hydrodynamics of a gas-solid flow in a bubbling fluidized bed. © 2013 John Wiley & Sons, Ltd.

Novas aplicações de metaheurísticas na solução do problema de planejamento da expansão do sistema de transmissão de energia elétrica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

ECLAC Notes Nº 46

Regional Energy Integration Looks Distant But Could be Crucial WTO and Free Trade Agreement Dispute Settlement Mechanisms Progress OPINION Central America: Poor Terms for the Terms of Trade, by José Luis Machinea HIGHLIGHTS Integration Schemes in Crisis and the Convergence of Trade Agreements, by Osvaldo Rosales INDICATORS: Economic Growth and Employment Direct Action in Favour of Indigenous Peoples and Afro-descendents Rises Recent Titles Calendar

Análise bayesiana do modelo fatorial dinâmico para um vetor de séries temporais utilizando a distribuição t multivariada

The multivariate t models are symmetric and with heavier tail than the normal distribution, important feature in financial data. In this theses is presented the Bayesian estimation of a dynamic factor model, where the factors follow a multivariate autoregressive model, using multivariate t distribution. Since the multivariate t distribution is complex, it was represented in this work as a mix between a multivariate normal distribution and a square root of a chi-square distribution. This method allowed to define the posteriors. The inference on the parameters was made taking a sample of the posterior distribution, through the Gibbs Sampler. The convergence was verified through graphical analysis and the convergence tests Geweke (1992) and Raftery & Lewis (1992a). The method was applied in simulated data and in the indexes of the major stock exchanges in the world.

Mecanismos de quase-mercado na educação escolar pública brasileira

Pós-graduação em Educação - FFC

As estratégias discursivas sobre políticas educacionais da ditadura militar: O caso da Revista de Cultura do Pará

Esta tese tem como objetivo analisar as estratégias discursivas sobre nacionalismo e identidade nacional presentes nos documentos educacionais e na Revista de Cultura do Pará e sua convergência na definição da política educacional paraense no período de 1970-1985. Este trabalho defende como argumentação que as estratégias discursivas convergentes dos documentos educacionais e da Revista de Cultura do Pará no período de 1970-1985, em função do jogo político e cultural do momento, impuseram sentidos definindo a política educacional (e uma política cultural respectivamente), pautada na ideologia do nacionalismo (e do regionalismo), e construiu nesse período uma identidade nacional e regional ajustada em uma noção de cidadania, o que contribuiu para a legitimidade e hegemonia do Regime Militar. A partir de uma metodologia centrada em análise documental da Revista de Cultura do Pará no período compreendido entre 1970-1979, e tendo como base a teoria de Pierre Bourdieu, bem como os postulados da teoria do nacionalismo de Anderson e Hobsbawm, o estudo conclui que esses intelectuais empreenderam estratégias discursivas de caráter integrador e conciliador de uma política nacional que visava à integração nacional, e, portanto, foram bastante harmônicas com as diretrizes políticas da ditadura civil-militar, bem como, tornaram-se uma referência obrigatória no processo de educação dos cidadãos, pela sua potencialidade de erigir uma perspectiva positiva em relação à nacionalidade, sua história e seu espaço.

Integração regional, fundos estruturais e estabilidade institucional no Mercosul: a criação do FOCEM

Este artigo analisa a criação e implementação do Fundo para Convergência Estrutural do Mercosul (FOCEM) frente ao contexto político-institucional do bloco e às estratégias de política externa dos seus sócios. Procura demonstrar que, para além de seu objetivo declarado de promover a convergência estrutural e a coesão social entre os Estados-membros, o fundo estabeleceu-se também como instrumento para evitar o descontentamento das menores economias com os resultados da integração e, assim, contribuir para a estratégia dos sócios maiores, calcada na estabilidade sem aprofundamento institucional do Mercosul.

Breves considerações sobre o conceito de natureza na genese da geografia moderna

From the twentieth century is witnessing a gradual increase in the debates and issues related to the degradation of nature, making the twenty-first century begins under the aegis of speeches linked to this concept as one of the axes of the concerns of humanity. There are several movements that are related to the degrading way of contemporary society and how we are called upon daily to save and defend nature, from the consumption of sustainable products through environmentally friendly lifestyles. While this may appear to be explicit that the current form of metabolic interaction man / nature in the current historical period of capitalism converges in a bleak scenario, however, there is an ideological and peacemaker convergence between productively and the systematic appeal to the consumption. Given these assumptions could be palpable the question that in the course of human history would be ideological conceptions of nature? Being a true statement what is the conflict present in the ideological struggle over nature with regard to the genesis of modern geography? Would it be overt or covert? These questions lead us to the present study, whose goal is to bring some notes about the ideological conceptions of the nature in human history, culminating in the possible influences upon the institutionalization of Modern Geography