Revista de Matemáticas 18(2)

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  • Ítem
    Geostatistical Spatio-Time model of crime in el Salvador: Structural and Predictive Analysis
    (2011-07-26 00:00:00) Alvarado, Welman Rosa
    Today, to study a geospatial and spatio-temporal phenomena requires searching statistical tools that enable the analysis of the dependency of space, time and interactions. The science that studies this kind of subjects is the Geoestatics which the goal is to predict spatial phenomenon. This science is considered the base for modeling phenomena that involves interactions between space and time. In the past 10 years, the Geostatistic had seen a great development in areas like the geology, soils, remote sensing, epidemiology, agriculture, ecology, economy, etc. In this research, the geostatistic had been apply to build a predictive map about crime in El Salvador; for that the variability of space and time together is studied to generate crime scenarios: crime hot spots are determined, crime vulnerable groups are identified, to improve political decisions and facilitate to decision makers about the insecurity in the country.
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    A Hybrid Random Number Generator(HRNG)
    (2011-07-29 00:00:00) Skliar, Osvaldo; Monge, Ricardo E.; Medina, Víctor; Gapper, Sherry; Oviedo Blanco, Guillermo
    The purpose of this paper is to present a novel Hybrid Random Number Generator (HRNG). Here “hybrid” refers to the fact that to construct this generator it is necessary to use 1)physical components – texts – and a physical process, and 2) a mathematical procedure. This HRNG makes it possible to generate genuine random numbers which may be used both for computer simulation of probabilistic systems and in the field of cryptography. The results of a comparative study of the binary strings generated by this HRNG and of those generated by two highly used implementations of a congruential algorithm designed to generate pseudorandom numbers are given here. One of the latter is the implementation incorporated into the Java 2 platform (version 1.6), and the other is the implementation incorporated into the runtime library of Microsoft’s Visual C++ 2008 compiler.
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    Sensor Fusion Using Entropic measures of Dependence
    (2011-07-26 00:00:00) Deignan, Paul B.
    As opposed to standard methods of association which rely on measures of central dispersion, entropic measures quantify multivalued relations. This distinction is especially important when high fidelity models of the sensed phenomena do not exist. The properties of entropic measures are shown to fit within the Bayesian framework of hierarchical sensor fusion. A method of estimating probabilistic structure for categorical and continuous valued measurements that is unbiased for finite data collections is presented. Additionally, a branch and bound method for optimal sensor suite selection suitable for either target refinement or anomaly detection is described. Finally, the methodology is applied against a known data set used in a standard data mining competition that features both sparse categorical and  ontinuous valued descriptors of a target. Excellent quantitative and computational results against this data set support the conclusion that the proposed methodology is promising for general purpose low level data fusion.
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    Preference of effective Factors in suitable selection of Microtunnel boring machines (mtbm) by using the fuzzy analytic hierarchy process (fahp) approach
    (2011-07-08 00:00:00) Jafari, Alireza; Ataie, Mohammad; Esmaiel Jalali, Sayed Mohammad; Ramazanzadeh, Ahmad
    The development of underground infrastructure, environmental concerns, and economic trend is influencing society. Due to the increasingly critical nature of installations of utility systems especially in congested areas, the need for monitoring and control system has increased. The microtunneling system will therefore have to provide for possibility of minimized surface disruption. Suitable selection of Microtunneling Boring Machine (MTBM) is the most curial decision that manager must be done. Because once the trenchless excavation has started, it might be too late to make any changes in equipment without extra costs and delays. Therefore, the various factors and parameters are affecting the choice of machine. In this paper discusses a developed methodology based on Fuzzy Analytic Hierarchy Process (FAHP) in order to determine weights of the criteria and sub criteria and then ranking them. Within the proposed model, four criteria site, machinery, structural, labor force impact and 18 sub-criteria are specified. The linguistic level of comparisons produced by experts are tapped and constructed in a form of triangular fuzzy numbers in order to construct fuzzy pair wise comparison matrices. Therefore, FAHP uses the pair wise comparison matrices for determining the weights of the criteria and sub-criteria.
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    Parallelization of a Quantum-Classic Hybrid Model For Nanoscale Semiconductor Devices
    (2011-07-26 00:00:00) Salas Huertas, Oscar; Lanucara, Piero; Pietra, Paola; Rovida, Sergio; Sacchi, Giovanni
    The expensive reengineering of the sequential software and the difficult parallel programming are two of the many technical and economic obstacles to the wide use of HPC. We investigate the chance to improve in a rapid way the performance of a numerical serial code for the simulation of the transport of a charged carriers in a Double-Gate MOSFET. We introduce the Drift-Diffusion-Schrödinger-Poisson (DDSP) model and we study a rapid parallelization strategy of the numerical procedure on shared memory architectures.
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    search of hadamard matrices by turyn sequences
    (2011-07-08 00:00:00) Piza Volio, Eduardo
    In this paper we study the Hadamard matrices and some algorithms to generate them. We review some theoretical aspects about Hadamard's conjecture, which asserts that every positive integer multiple of 4 is a Hadamard number. Then we describe the methods of Kronecker, Sylvester, Paley, Williamson, Goethals-Seidel, Cooper- Wallis, Baumert-Hall, Ehlich and supplementary dierence sets. Subsequently we settle the Hadamard sieve: 668 is lowest order for which is unknown if there exist an Hadamard matrix. Finally we propose a simulated annealing algorithms as alternative to nd Hadamard matrices from Turyn sequences. We found excellent solutions with this search method.
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    A genetic algorithm in a schedule problem with special constraints
    (2011-07-08 00:00:00) Pérez de la Cruz, Carlos; Ramírez Rodríguez, Javier
    Ramírez (2001) introduced the generalized robust coloring problem (GRCP), this problem lets solve timetabling problems which considers constraints such as: two events can not be assigned at the same time and there must be at least d days between two events.The GRCP deals with a robust coloring for a given graph with a fixed number of colors, not necessarily the chromatic number and considers the distance between colors as the penalization of complementary edges. It was shown that the problem is NP-complete, so it is necessary to use approximate methods to find good solutions in a reasonable time. This paper presents a hybrid of a genetic algorithm with a local search for cases of 30-120 hours per week; it is shown that for some cases the found solution is optimal and in other cases the solutions are very promising.