Revista de Matemáticas 11(2)
URI permanente para esta colección
Examinar
Envíos recientes
Ítem A mixed-effects model for growth curves analysis in a two-way crossed classification layout(2009-02-20 00:00:00) Ojeda, Mario Miguel; Sahai, HardeoWe propose a mixed-effects linear model for analyzing growth curves data obtainedusing a two-way classification experiment. The model combines an unconstrainedmeans model and a regression model on the time, in which the coefficients are consideredrandom. The model allows for experimental unit covariates so as to study thetrend and the variability of the individual growth curves. Comments on data analysisstrategies are provided. An application of the model is illustrated using a data-setcomes from a chrysanthemum growth experiment.Keywords: multilevel linear regression models, random coefficients models, means models,data analysis strategies.Ítem Estimación del error en cierta clase de métodos numéricos combinados de estrategia recorrectora(2009-02-20 00:00:00) Marrero Severo, Aymée de los Ángeles; Baguer Díaz-Romañach, Marta L.This paper shows an analysis of the order for the approximation and roundofferrors in combined numerical scheme with recorrector strategy of Adams–Moulton–Bashfort family. These methods are used for the numerical solution of the estimationproblem in models defined by dynamical ODE. Our interest is avail oneself of “familyor kind” of methods which will be efficient or at least competitive for the numericalsolutions of this type of problems. This strategy is consistent with the present tendency in the use of models with minimal square objective function for the adjustment viaoptimization algorithms with and without constrained and explicit, semi-explicit orimplicit numerical methods.Keywords: Recorrector strategy numerical methods, multi-step, stiffness, roundoff errors.Ítem Definición de semiproductos escalares útiles en análisis de datos(2009-02-20 00:00:00) Trejos Zelaya, JavierWe develop the theory necessary for Data Analysis with inner semiproducts, extendingtha classical concepts of inner products usually employed. For this, we usethe basic algebraic definitions of non degenerated bilinear forms and develop all thealgebraic tools needed. We study the most important operators on the individualspace, such as the VM and the MV operators. We also study the case of the innersemiproduct of weights in the variable space, which corresponds to the introduction ofsupplementary individuals in the case of null weights. Finally, we arrive to the usualconcepts of Principal Component Analysis.Keywords: inner semiproducts, non degenerated bilinear forms, semimetrics, orthogonalprojection operator, principal component analysis.Ítem Graph dominance by rook domains for Znp and Zn3 × Zm2 graphs(2009-02-20 00:00:00) Piza Volio, EduardoDescribed within is the problem of finding near-minimum dominating subsets of agiven graph by rook domains. Specifically, we study the graphs of the kind ZnpandZn3×Zm2and introduce a simulated annealing algorithm to compute upper bounds ofthe size of minimum dominating subsets.We demonstrate the effectiveness of the algorithm by comparing the results with apreviously studied class of graphs, including the so-called “football pool” graphs andothers. We give some new upper bounds for graphs of the kind Znp, with p 4. Thecodes of some dominating subsets are given in an appendix.Keywords: Graph domination, simulated annealing, football pool problem, combinatorics.Ítem Some Aspects in n-dimensional almost Periodic functions iii(2011-04-29 00:00:00) Arguedas Troyo, Vernor; Castro Fernández, EdwinThe properties of almost periodical functions and some new results have been published in [CA1], [CA2] and [CA3] In this paper we show some new definitions in order to analize some singularities. For this functions we find some uniqueness sets in $$\mathbb{R}$$ and $$\mathbb{R^{n}}$$. The paper finishes analizing the relation of this functions and the function sinc.Ítem Invariant Manifolds in Parametric turbulent Models(2011-04-29 00:00:00) Grebenev, Vladimir N; Chernykh, G. G.The article is devoted to examining the so-called local-equilibrium approximations used while modeling turbulent flows. The dynamics of a far plane turbulent wake are investigated as an example. In this article, we analyze these approximations by using the method of differential constraints. We show that some algebraic models based on using the local-equilibrium approximation can be interpreted as equations of invariant manifolds generated by the models under consideration. Reduction of the models on the corresponding invariant manifolds made it possible to find self similar solutions and to separate explicit solutions. Moreover, some empirical constants may be calculated and their obtained values are close to the recommended quantities.