Revista de Matemáticas 20(1)

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  • Ítem
    Sobre una construcción de un monoide libre con identidad sobre un topos E con el objeto de los números naturales
    (2013-04-04 00:00:00) Acuña Ortega, Osvaldo
    We proved that the free moniod with identify in X isM(X)= R \in \Omega^{NxNxX/R} es funcional y \_n \in N dom R=(n)} -----> ix  \Omega^{NxNxX/R}.
  • Ítem
    The use of multilayer perceptrons for statistical modeling SO_2 non linear time series in Salta Capital, Argentina
    (2013-04-04 00:00:00) Musso, Haydeé Elena; Ávila Blas, Orlando José
    In this paper a statistical study of phisical-chemistry variables connected with enviroment pollution, specifically SO2 monthly average concentration, measured in Salta Capital city, Argentina, together with NO2 and O3 concentrations, was made. Time series under study shown non linear dinamic behaviour, outliers and structural changes. Due to these it was impossible to use typical econometric typologies (AR, MA, ARMA, ARIMA, among others). Aneffective solution which uses multistep perceptrons theory was found. By using structural time series modelling, this solution is presentedby an iterative mathematical process that allows us to obtain a finalmodel with a high confidence level (95%) in order to do thefore casting step on the studied variable.
  • Ítem
    Simulation of decametric wave propagation in the ionospheric plasma
    (2013-04-04 00:00:00) Kiryanova, Kseniya S.; Kryukovsky, Andrey S.; Lukin, Dmitry S.
    The decametric radiowaves propagation in the ionospheric plasmawas considered. Bicharacteristic system of equations was used in themodeling ray structures. This system, which allows finding the raypaths with great precision, was obtained by D.S. Lukin. Models ofthe ionosphere with horizontal gradients were used in the calcula-tions; local inhomogeneities, such as reduced electron density in themaximum layer and increased electron density below the maximumlayer, were taken into account. The features of shortwave propaga-tion, such as getting a wave of interlayer channel, distribution andout of it, reflection of waves from different ionospheric layers wereexplored. Was shown that the rays can be ejected from the field ofdistribution and curled when hit in the inhomogeneity of the iono-sphere. The formation of caustic surfaces and its dynamics werestudied. The radiowaves propagation in the Earth’s ionosphere wasstudied. This ionosphere profiles were restored the scientific groupled by Professor V.E. Kunitsyn by radiotomographymethod based onreal observations. Ray structures in the area of “equatorial anomaly”were built. The models, both including and excluding the effect ofEarth’s magnetic field and the influence of the equatorial anomalywere considered. Ray structures at the different positions of the ra-diation source, as well as different operating frequency, were investi-gated. Dynamic model of the ray’s propagation was developed.
  • Ítem
    One-side oscillation strategic approach
    (2013-04-04 00:00:00) Beausoleil, Ricardo P.; Valcárcel Miró, Yasser
    This paper reports an approach developed to find a good quality solution for a generalized assignment problem with application to the Dimensional Cutting Problem. The objective at the Cutting Problemis to divide different pools of pieces of the same dimension among different items of available material all having two dimensions, the width and length. The solution is found keeping the largest number of pieces in a single material. Some initial numerical experiences found for the algorithm optimal and suboptimal solutions orinstances of more than 500 pieces at a very low computational cost.
  • Ítem
    Estimación de parámetros de regresión no lineal mediante colonia de abejas artificiales
    (2013-04-04 00:00:00) de los Cobos Silva, Sergio Gerardo; Gutiérrez Andrade, Miguel Ángel; Rincón García, Eric Alfredo; Lara Velázquez, Pedro; Aguilar Cornejo, Manuel
    Este trabajo presenta los resultados de la técnica heurística de ABC (Artificial Bee Colony) utilizada para estimar los parámetros de modelos de regresión no lineal. El algoritmo fue probado sobre 27 bases de datos de la colección NIST (2001), de las cuales 8 se consideran con un alto grado de dificultad. Se presentan los resultados experimentales.
  • Ítem
    Pattern equation method for the solution of electromagnetic scattering by axially-symmetric particles with complex anisotropic surface impedance
    (2013-04-04 00:00:00) Kyurkchan, Alexander G.; Demin, Dmitry B.
    The pattern equation method (PEM) has been extended to solve the scattering problems of electromagnetic waves by particles with mixed anisotropic surface impedance. Thus, the anisotropic impedance boundary conditions are imposed on lateral surface of the particle, and isotropic impedance boundary conditions are imposed on end faces of the particle. The method is formulated for axially-symmetric bodies. The scattering characteristics of the bodies with artificially soft and hard lateral surfaces are presented. The comparison of the results with those obtained by other methods is carried out. The analysis of convergence’s rate of numerical algorithm of the PEMand accuracy of numerical calculations are presented. Comparison of our data with numerical results obtained earlier by the PEM in absence of an anisotropic impedance is carried out.