Revista de Matemáticas 11(1)
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Ítem Algoritmos Numéricos para el Problema de Restauración de Imágenes usando el Método de las Proyecciones Alternantes(2011-04-29 00:00:00) Escalante, RenéThe projection algorithms have evolved from the alternating projection method proposed by J. von Neumann in 1933, who treated the problem of finding the projection of a given point in a Hilbert space onto the intersection of two closed subspaces. Recent researches have been centered in techniques for accelerate the convergence ofthe method and to exploit the multiprocessing. In this work we considered the image restoration problem. In most techniques developed to solved it have used iterative algorithms; one of them consists of using alternating orthogonal projections. We carried out one chronological looking back of different techniques in which has been applied the method of the alternating orthogonal projections to the problem of imagen restoration, until arriving at the recent approach of Combettes (1997-1999), on where the restoration process is based on the computation of approximate projections (i.e., subgradient projections), instead of exact projectionsÍtem Introducción de factores de riesgo en los Métodos de Knox y Grimson para el Estudio de Conglomerados Espacio Temporales(2011-04-29 00:00:00) Casas Cardoso, Gladys M.; Grau Abalo, Ricardo; Cardoso Romero, GladysThere are not infallible disease clusters methods, so it is necessary to know exactly when their results are reliable. In this paper space data were simulated using two uniform distributions and time data, following the pattern of simple epidemic model. Behaviour of both tests: Knox and Grimson were studied. Besides the conduct of both tests with risks factors were analysed. Numerical computing were done with Mathematica software.Ítem Fitting non-gaussian Models to Financial data: An Empirical Study(2011-04-29 00:00:00) Olivares, Pablo; Álvarez, AlexánderIn this paper are presented some experiences about the modeling of financial data by three classes of models as alternative to Gaussian Linear models. Dynamic Volatility, Stable L'evy and Diffusion with Jumps models are considered. The techniques are illustrated with some examples of financial series on currency, futures and indexes.Ítem Agrupamiento de Filas y Columnas Homogéneas en Modelos de Correspondencia(2011-04-29 00:00:00) Marinelli, Claudia; Winzer, NélidaGoodman(1981) proposed homogeneity and structures criterias in Associaton Models which allow to determine if certain rows or columns in a contingency table should be grouped. In later works, he showed the relations between canonicals scores and the one corresponding to an Association Models. Gilula (1986) developed grouping results suggested by the canonical scores in a contingency table under a RC Canonical Correlation Model. On the other hand, Correspondence Analysis can be seen like a reparametrization of Canonical Correlation Model by virtue of Goodman (1986) and Van der Heijden et al. (1994) result.Ítem Bounded Variables nonlinear Multiple Criteria Optimization using Scatter search(2011-05-06 00:00:00) Beausoleil, Ricardo P.This paper introduces an adaptation of multiple criteria scatter search to deal with nonlinear continuous vector optimization problems on bounded variables, applying Tabu Search approach as diversification generator method. Frequency memory and another escape mechanism are used to diversify the search. A relation Pareto is apply in order to designate a subset of the best generated solutions to be reference solutions. A choice function called Kramer Selection is used to divide the reference solution in two subsets. The Euclidean distance is used as a measure of dissimilarity in order to find diverse solutions to complement the subsets of high quality current Pareto solutions to be combined. Convex combination is used as a combined method. The performance of this approach is evaluated on several test problems taken from the literature.Ítem Hércules contra la Hidra y la muerte del Internet(2011-04-29 00:00:00) Piza Volio, EduardoHercules killed the Hydra of Lerna in a bloody battle—the second of the labor tasks imposed upon him in atonement for his hideous crimes. The Hydra was a horrible, aggressive mythological monster with many heads and poisonous blood, whose heads multiplied each time one of them was severed. This article explores some mathematical methods about this interesting epic battle. A generalization of the original Kirby & Paris model is proposed. We also study the connection of this model with Goodstein ultra-growing and recursive sequences. As an interesting application, we next analyze the inevitable death of another huge monster of our modern era: the Internet.