André Lima Férrer de Almeida

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This work was originally motivated by a classification of tensors proposed by Richard Harshman. In particular, we focus on simple and multiple “bottlenecks”, and on “swamps”. Existing theoretical results are surveyed, some numerical algorithms are described in details, and their numerical complexity is calculated. In particular, the interest in using the(More)
In this paper, we formulate a new tensor decomposition herein called constrained factor (CONFAC) decomposition. It consists in decomposing a third-order tensor into a triple sum of rank-one tensor factors, where interactions involving the components of different tensor factors are allowed. The interaction pattern is controlled by three constraint matrices(More)
In this paper, we consider an uplink multiple-antenna code-division multiple-access (CDMA) system linking several multiple-antenna mobile users to one multiple-antenna base station. For this system, a constrained third-order tensor decomposition is introduced for modeling the multiple-antenna transmitter as well as the received signal. The constrained(More)
Blind identification of underdetermined mixtures can be addressed efficiently by using the second ChAracteristic Function (CAF) of the observations. Our contribution is twofold. First, we propose the use of a Levenberg-Marquardt algorithm, herein called LEMACAF, as an alternative to an Alternating Least Squares algorithm known as ALESCAF, which has been(More)
Resumo—Este artigo formula um novo receptor para a decodificação cega de códigos espaço-frequência em sistemas multiantena. A proposta para o projeto do sinal transmitido combina espalhamento em frequência do tipo Vandermonde com uma precodificação linear de constelação variante no tempo. Esta última consiste em estender a rotação de constelação sobre(More)
In this work, we propose the use a multivariate analysis tool, called principal components analysis (PCA), to address the problem of Students' Evaluation of Teaching Effectiveness (SETE). We conducted a research with Engineering Students in an undergraduate course. The values obtained after collecting research data were transformed from a 3D array to a 2D(More)
In this paper, we present an overview of constrained parallel factor (PARAFAC) models where the constraints model linear dependencies among columns of the factor matrices of the tensor decomposition or, alternatively, the pattern of interactions between different modes of the tensor which are captured by the equivalent core tensor. Some tensor prerequisites(More)