990 resultados para Local linear
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Pós-graduação em Biopatologia Bucal - ICT
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Aborda, por um lado, a relação entre a economia local no Município de Oriximiná - PA e sua inserção no Comércio Internacional do minério de alumínio. E, por outro, os mecanismos de interação e alianças entre os atores locais público e privado com o setor minerador de alumínio, representado pela Companhia MRN, vis à vis a consecução de um projeto de desenvolvimento local em bases endógenas. O estudo busca compreender como a interação entre interesses públicos/privados, coletivos/individuais, orgânicos/corporativos em âmbito local influenciam no desenvolvimento endógeno do Município. Não obstante, avaliar a dimensão das restrições estruturais, condicionadas pela dinâmica das relações comerciais no setor mundial do minério de Alumínio, aos processos internos de articulação para o desenvolvimento local. O Problema proposto está em compreender como as oportunidades e restrição da explotação de uma mina world class impulsiona processos de desenvolvimento local. Partindo-se da Nova Teoria Econômica aliada à Teoria do Comércio Internacional e Geografia Econômica, buscou-se delinear os parâmetros de inserção da economia mineradora do alumínio local no cenário internacional e suas inter-relações resultantes, sejam estas sob o aspecto tecnológico ou mercadológico. Numa perspectiva local, procurou-se identificar os processos interativos e seu grau de convergência entre Setor Público (via Plano Diretor Municipal) com vistas à concretização de um projeto de desenvolvimento endógeno mediado pela formação de alianças (Clusters) que atendessem às suas respectivas exigências tecnológica, econômica e institucional. Para tanto, o trabalho recorreu às Teorias do Crescimento e Desenvolvimento econômico e dos Sistemas para explicitar os mecanismos que regem as interações entre os atores locais e, em última análise, determinam suas ações sociais no processo de desenvolvimento endógeno. O método adotado é o hipotético-dedutivo utilizando-se instrumentos de coleta de dados secundários e primários. Através de um processo de modelagem computacional e, recorrendo aos Relatórios Fiscais da Prefeitura de Oriximiná e Contábeis da Mineração Rio do Norte buscou-se o aprofundamento sobre a natureza e aplicação dos recursos gerenciados por ambas Instituições. Desenvolve-se ainda, um modelo representativo da dinâmica do desenvolvimento endógeno local tendo o PIB Municipal per capita como proxy através do método de análise multivariada utilizando a técnica da regressão linear múltipla. Desenvolve-se também uma análise da autocorrelação da economia de Oriximiná com o seu entorno a partir da técnica de processamento de dados espaciais geograficamente referenciados bem como a técnica de acessibilidade locacional de Oriximiná. A apresentação dos resultados utiliza modelos simbólicos, tabelas e gráficos diversos. A conclusão é de que a atividade minerária encontra-se descolada do processo de crescimento local por não produzir spillover e por não internalizar o grosso da sua renda no Município dada sua estratégia competitiva. Contudo, a dinâmica local também sofre restrições por conta de sua localização espacial à margem do eixo econômico Regional e pela baixa capacidade empreenditiva e articulatória demonstrada pela administração pública local.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Linear Versus Geometric Morphometric Approaches for the Analysis of Head Shape Dimorphism in Lizards
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The erosion is a natural process of detachment, transport and deposition of soil and rock particles from one place to another. Human activities with no previous planning may accelerate this process, causing several damages to the environment and to society. In order to control the acceleration of these erosion processes caused by humans, prevention and improvement initiatives emerge. Regarding works which interfere directly in some of the natural resources, these initiatives must respect the intrinsic physical properties of the area of interest, if they aim to obtain effective results. Based on this scenario, this work proposes a few methods of accelerated linear erosion prevention, control and recovery in a specific area of the municipal district of Ipeúna (SP). For that matter, this study is based on a method of physiographic compartmentalization of the area, considering and integrating soil, relief, geology and the use and land cover properties of the study area. Plus, a flowchart with general orientations regarding management of eroded areas was produced, focused on the control and recovery of linear erosion. The result demonstrates the importance of careful erosion control, respecting the physical properties of each physiographic unit. The vegetative and mechanical conservationists methods, and the discipline of water flow, have found wide applicability in the study area.
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Estimates of evapotranspiration on a local scale is important information for agricultural and hydrological practices. However, equations to estimate potential evapotranspiration based only on temperature data, which are simple to use, are usually less trustworthy than the Food and Agriculture Organization (FAO)Penman-Monteith standard method. The present work describes two correction procedures for potential evapotranspiration estimates by temperature, making the results more reliable. Initially, the standard FAO-Penman-Monteith method was evaluated with a complete climatologic data set for the period between 2002 and 2006. Then temperature-based estimates by Camargo and Jensen-Haise methods have been adjusted by error autocorrelation evaluated in biweekly and monthly periods. In a second adjustment, simple linear regression was applied. The adjusted equations have been validated with climatic data available for the Year 2001. Both proposed methodologies showed good agreement with the standard method indicating that the methodology can be used for local potential evapotranspiration estimates.
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The main feature of partition of unity methods such as the generalized or extended finite element method is their ability of utilizing a priori knowledge about the solution of a problem in the form of enrichment functions. However, analytical derivation of enrichment functions with good approximation properties is mostly limited to two-dimensional linear problems. This paper presents a procedure to numerically generate proper enrichment functions for three-dimensional problems with confined plasticity where plastic evolution is gradual. This procedure involves the solution of boundary value problems around local regions exhibiting nonlinear behavior and the enrichment of the global solution space with the local solutions through the partition of unity method framework. This approach can produce accurate nonlinear solutions with a reduced computational cost compared to standard finite element methods since computationally intensive nonlinear iterations can be performed on coarse global meshes after the creation of enrichment functions properly describing localized nonlinear behavior. Several three-dimensional nonlinear problems based on the rate-independent J (2) plasticity theory with isotropic hardening are solved using the proposed procedure to demonstrate its robustness, accuracy and computational efficiency.
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The beta-Birnbaum-Saunders (Cordeiro and Lemonte, 2011) and Birnbaum-Saunders (Birnbaum and Saunders, 1969a) distributions have been used quite effectively to model failure times for materials subject to fatigue and lifetime data. We define the log-beta-Birnbaum-Saunders distribution by the logarithm of the beta-Birnbaum-Saunders distribution. Explicit expressions for its generating function and moments are derived. We propose a new log-beta-Birnbaum-Saunders regression model that can be applied to censored data and be used more effectively in survival analysis. We obtain the maximum likelihood estimates of the model parameters for censored data and investigate influence diagnostics. The new location-scale regression model is modified for the possibility that long-term survivors may be presented in the data. Its usefulness is illustrated by means of two real data sets. (C) 2011 Elsevier B.V. All rights reserved.
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Spatial linear models have been applied in numerous fields such as agriculture, geoscience and environmental sciences, among many others. Spatial dependence structure modelling, using a geostatistical approach, is an indispensable tool to estimate the parameters that define this structure. However, this estimation may be greatly affected by the presence of atypical observations in the sampled data. The purpose of this paper is to use diagnostic techniques to assess the sensitivity of the maximum-likelihood estimators, covariance functions and linear predictor to small perturbations in the data and/or the spatial linear model assumptions. The methodology is illustrated with two real data sets. The results allowed us to conclude that the presence of atypical values in the sample data have a strong influence on thematic maps, changing the spatial dependence structure.
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This paper addresses the numerical solution of random crack propagation problems using the coupling boundary element method (BEM) and reliability algorithms. Crack propagation phenomenon is efficiently modelled using BEM, due to its mesh reduction features. The BEM model is based on the dual BEM formulation, in which singular and hyper-singular integral equations are adopted to construct the system of algebraic equations. Two reliability algorithms are coupled with BEM model. The first is the well known response surface method, in which local, adaptive polynomial approximations of the mechanical response are constructed in search of the design point. Different experiment designs and adaptive schemes are considered. The alternative approach direct coupling, in which the limit state function remains implicit and its gradients are calculated directly from the numerical mechanical response, is also considered. The performance of both coupling methods is compared in application to some crack propagation problems. The investigation shows that direct coupling scheme converged for all problems studied, irrespective of the problem nonlinearity. The computational cost of direct coupling has shown to be a fraction of the cost of response surface solutions, regardless of experiment design or adaptive scheme considered. (C) 2012 Elsevier Ltd. All rights reserved.
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The asymptotic expansion of the distribution of the gradient test statistic is derived for a composite hypothesis under a sequence of Pitman alternative hypotheses converging to the null hypothesis at rate n(-1/2), n being the sample size. Comparisons of the local powers of the gradient, likelihood ratio, Wald and score tests reveal no uniform superiority property. The power performance of all four criteria in one-parameter exponential family is examined.
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In this study a new, fully non-linear, approach to Local Earthquake Tomography is presented. Local Earthquakes Tomography (LET) is a non-linear inversion problem that allows the joint determination of earthquakes parameters and velocity structure from arrival times of waves generated by local sources. Since the early developments of seismic tomography several inversion methods have been developed to solve this problem in a linearized way. In the framework of Monte Carlo sampling, we developed a new code based on the Reversible Jump Markov Chain Monte Carlo sampling method (Rj-McMc). It is a trans-dimensional approach in which the number of unknowns, and thus the model parameterization, is treated as one of the unknowns. I show that our new code allows overcoming major limitations of linearized tomography, opening a new perspective in seismic imaging. Synthetic tests demonstrate that our algorithm is able to produce a robust and reliable tomography without the need to make subjective a-priori assumptions about starting models and parameterization. Moreover it provides a more accurate estimate of uncertainties about the model parameters. Therefore, it is very suitable for investigating the velocity structure in regions that lack of accurate a-priori information. Synthetic tests also reveal that the lack of any regularization constraints allows extracting more information from the observed data and that the velocity structure can be detected also in regions where the density of rays is low and standard linearized codes fails. I also present high-resolution Vp and Vp/Vs models in two widespread investigated regions: the Parkfield segment of the San Andreas Fault (California, USA) and the area around the Alto Tiberina fault (Umbria-Marche, Italy). In both the cases, the models obtained with our code show a substantial improvement in the data fit, if compared with the models obtained from the same data set with the linearized inversion codes.
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The seismic behaviour of one-storey asymmetric structures has been studied since 1970s by a number of researches studies which identified the coupled nature of the translational-to-torsional response of those class of systems leading to severe displacement magnifications at the perimeter frames and therefore to significant increase of local peak seismic demand to the structural elements with respect to those of equivalent not-eccentric systems (Kan and Chopra 1987). These studies identified the fundamental parameters (such as the fundamental period TL normalized eccentricity e and the torsional-to-lateral frequency ratio Ωϑ) governing the torsional behavior of in-plan asymmetric structures and trends of behavior. It has been clearly recognized that asymmetric structures characterized by Ωϑ >1, referred to as torsionally-stiff systems, behave quite different form structures with Ωϑ <1, referred to as torsionally-flexible systems. Previous research works by some of the authors proposed a simple closed-form estimation of the maximum torsional response of one-storey elastic systems (Trombetti et al. 2005 and Palermo et al. 2010) leading to the so called “Alpha-method” for the evaluation of the displacement magnification factors at the corner sides. The present paper provides an upgrade of the “Alpha Method” removing the assumption of linear elastic response of the system. The main objective is to evaluate how the excursion of the structural elements in the inelastic field (due to the reaching of yield strength) affects the displacement demand of one-storey in-plan asymmetric structures. The system proposed by Chopra and Goel in 2007, which is claimed to be able to capture the main features of the non-linear response of in-plan asymmetric system, is used to perform a large parametric analysis varying all the fundamental parameters of the system, including the inelastic demand by varying the force reduction factor from 2 to 5. Magnification factors for different force reduction factor are proposed and comparisons with the results obtained from linear analysis are provided.
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Let Y_i = f(x_i) + E_i\ (1\le i\le n) with given covariates x_1\lt x_2\lt \cdots\lt x_n , an unknown regression function f and independent random errors E_i with median zero. It is shown how to apply several linear rank test statistics simultaneously in order to test monotonicity of f in various regions and to identify its local extrema.