Symmetric Models
Mostrando 13-24 de 67 artigos, teses e dissertações.
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13. Skew normal mixed models in microarray data generated from complex pedigrees / Modelos mistos normais assimÃtricos em dados de microarrays originados de pedigrees complexos / Modelos mistos normais assimÃtricos em dados de microarrays originados de pedigrees complexos / Skew normal mixed models in microarray data generated from complex pedigrees
Estimates of heritability for gene expression are scarce and commonly originated from family structures, in which the variability of responses among and within families are provided under a uniform covariance structure for related individuals, ignoring the known relationship among all individuals in the pedigree. Gauss-Markov normal mixed models are the usua
Publicado em: 2009
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14. RICE AND RED RICE DEVELOPMENT: MODELING AND RESPONSE TO CLIMATE CHANGE / DESENVOLVIMENTO DO ARROZ E DO ARROZ VERMELHO: MODELAGEM E RESPOSTA À MUDANÇA CLIMÁTICA
Increases of 1.1 to 6.4C in temperature are projected by the end of the XXI century in several locations, including Brazil. Among processes that may be affected by increasing temperatures is the duration of the developmental cycle of crops. Simulation models are tools that allow to describe the possible interactions that take place in agroecoystems and their
Publicado em: 2008
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15. EFFICIENCY ASSESSMENT OF ADVANCED MODAL ANALYSIS AS COMPARED TO TECHNIQUES BASED ON NUMERICAL INVERSE TRANSFORMS / COMPARAÇÃO DO DESEMPENHO COMPUTACIONAL DA TÉCNICA DE SUPERPOSIÇÃO MODAL AVANÇADA COM TÉCNICAS DA TRANSFORMADA DE LAPLACE
An established technique to solve time-dependent problems is the formulation of a complete frequency-domain analysis via Laplace or Fourier transforms, with subsequent ad hoc expression of results by numerical inversion. Although usually easy to implement, such a transform inversion is computationally intensive, if accurate results are desired, and liable to
Publicado em: 2008
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16. Função de acoplamento t-Student assimetrica : modelagem de dependencia assimetrica / Skewed t-Student copula function : skewed dependence modelling
The Skewed t-Student distribution family, constructed upon the multivariate normal mixture distribution, known as mean-variance mixture, composed with the Inverse-Gamma distribution, has many desirable flexibility properties for many distribution asymmetry structures. These properties are explored by constructing copula functions with asymmetric dependence.
Publicado em: 2008
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17. Um modelo geometricamente exato de barras com grandes deformações, que considera a distorção e o empenamento geral da seção transversal, e sua discretização pelo método dos elementos finitos. / A fully nonlinear geometrically exact multi-parameter rod model that incorporates general in-plane and out-of-plane cross-sectional changes, and its discretization by Finite Element Method.
The main purpose of this work is to present a fully nonlinear geometrically-exact multi-parameter rod model that incorporates general in-plane cross-sectional changes as well as general out-of-plane cross-sectional warping. The formulation constitutes an extension of the earlier works presented in [1] to [6], [8] and [9], in the sense that the restrictions t
Publicado em: 2008
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18. Plane symmetric bulk viscous domain wall in Lyra geometry
In this paper general solutions are found for domain walls in Lyra geometry in the plane symmetric spacetime metric given by Taub. Expressions for the energy density and pressure of domain walls are derived in both cases of uniform and time varying displacement field beta. Some physical consequences of the models are also given. Finally, the geodesic equatio
Brazilian Journal of Physics. Publicado em: 2007-09
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19. Rotating and counterrotating relativistic thin disks as sources of stationary electrovacuum spacetimes
A detailed study is presented of the counterrotating model (CRM) for electrovacuum stationary axially symmetric relativistic thin disks of infinite extension without radial stress, in the case when the eigenvalues of the energy-momentum tensor of the disk are real quantities, so that there is not heat flow. We find a general constraint over the counterrotati
Brazilian Journal of Physics. Publicado em: 2007-09
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20. AperfeiÃoamento de testes de hipÃteses para modelos nÃo-lineares simÃtricos
Neste trabalho, tratamos de refinamentos para testes de hipÃteses em modelos de regressÃo nÃo-lineares simÃtricos, assumindo que o parÃmetro de escala à desconhecido. Apresentamos, em notaÃÃo matricial, fatores de correÃÃo de Bartlett e tipo-Bartlett para melhorar as estatÃsticas da razÃo de verossimilhanÃas e escore, respectivamente, nesta clas
Publicado em: 2007
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21. Emergence of complex spatio-temporal order in nonlinear field theories
We investigate the emergence of time-dependent nonperturbative configurations during the evolution of nonlinear scalar field models with symmetric and asymmetric double-well potentials. Complex spatio-temporal behavior emerges as the system seeks to establish equipartition after a fast quench. We show that fast quenches may dramatically modify the decay rate
Brazilian Journal of Physics. Publicado em: 2006-12
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22. Um modelo de espaço de estados com representação de segunda ordem para a analise das oscilações de modo interarea em sistemas de energia eletrica / A space state model including second order representation for the analysis of power systems inter-area mode oscillations
In this work, the analysis of power systems inter-area mode oscillations is performed by the application of two different methodologies: first, the linear modal analysis, and then the analysis including second order nonlinear terms from a Taylor series expansion, with the application of the method of normal forms of vector fields. In this case, the method of
Publicado em: 2005
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23. Classification of energy momentum tensors in n > 5 dimensional space-times: a review
Recent developments in string theory suggest that there might exist extra spatial dimensions, which are not small nor compact. The framework of a great number of brane cosmological models is that in which the matter fields are confined on a brane-world embedded in five dimensions (the bulk). Motivated by this we review the main results on the algebraic class
Brazilian Journal of Physics. Publicado em: 2004-06
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24. Critical behavior of ferromagnetic spin models with aperiodic exchange interactions
We review recent investigations of the critical behavior of ferromagnetic q-state Potts models on a class of hierarchical lattices, with exchange interactions according to some deterministic but aperiodic substitution rules. The problem is formulated in terms of exact recursion relations on a suitable parameter space. The analysis of the fixed points of thes
Brazilian Journal of Physics. Publicado em: 2000-12