Strategic Project - UI 212 - 2014

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Publications

Segregation and intrinsec restrictions on canonic variance components

Publication . Ferreira, Dário; Ferreira, Sandra S.; Nunes, Célia; Mexia, João T.

This paper deals with the estimability of variance components, in mixed models, when the dimension of the commutative algebra, spanned by all possible variance-covariance matrices, is greater than the number of linearly independente unknown variance components. As example we present an application to a random three-factor crossed-model.

2018Journal article

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Estimation of variance components in normal linear mixed models with additivity

Publication . Ferreira, Dário; Ferreira, Sandra S.; Nunes, Célia; Mexia, João T.

In this paper we use commutative Jordan Algebras to estimate variance components in linear mixed models. We apply the theory to a model in which three factors cross and one of the factors is additive to the other two.

2015Journal article

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Finite element schemes for a class of nonlocal parabolic systems with moving boundaries

Publication . Almeida, Rui M.P.; Duque, José C. M.; Ferreira, Jorge; Robalo, Rui

The aim of this paper is to study the convergence, properties and error bounds of the discrete solutions of a class of nonlinear systems of reaction–diffusion nonlocal type with moving boundaries, using the finite element method with polynomial approximations of any degree and some classical time integrators. A coordinate transformation which fixes the boundaries is used. Some numerical tests to compare our Matlab code with a moving finite element method are investigated.

2018-05Journal article

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Nonuniform behavior and stability of Hopfield neural networks with delay

Publication . Bento, António; Oliveira, José J.; Silva, César M.

Based on a new abstract result on the behavior of nonautonomous delayed equations, we obtain a stability result for the solutions of a general discrete nonautonomous Hopfield neural network model with delay. As an application we improve some existing results on the stability of Hopfield models.

2017Journal article

Open access

On skew-symmetric matrices related to the vector cross product in R^7

Publication . Beites, P. D.; Nicolás, Alejandro; Vitoria, Jose

A study of real skew-symmetric matrices of orders 7 and 8, de ned through the vector cross product in R7, is presented. More concretely, results on matrix properties, eigenvalues, (generalized) inverses and rotation matrices are established.

2017Journal article

Open access