5,029 research outputs found
Self-adaptation of Genetic Operators Through Genetic Programming Techniques
Here we propose an evolutionary algorithm that self modifies its operators at
the same time that candidate solutions are evolved. This tackles convergence
and lack of diversity issues, leading to better solutions. Operators are
represented as trees and are evolved using genetic programming (GP) techniques.
The proposed approach is tested with real benchmark functions and an analysis
of operator evolution is provided.Comment: Presented in GECCO 201
Localized Algebraic K-theory
Let K(,*)(A; /L(\u27n)) denote the mod-L(\u27n) algebraic K-theory of a 1/L -algebra A. V. Snaith has studied Bott-periodic algebraic K-theory K(,i)(A; /L(\u27n)) 1/(beta)(,n) , the direct limit of iterated multiplications by (beta)(,n), the \u27Bott element\u27, using the K-theory product. For L an odd prime, Snaith has given a description of K(,*)(A; /L(\u27n))(1/(beta)(,n)) using Adams maps between Moore spectra. These constructions are interesting, in particular, for their connections with the Lichtenbaum-Quillen conjecture.;In this thesis we obtain an analogous description of K(,*)(A; /2(\u27n)) 1/(beta)(,n) , n (GREATERTHEQ) 2, for an algebra A with 1/2 (ELEM) A and such that A contains a fourth root of unity. We approach this problem using low dimen- sional computations of the stable homotopy groups of B /4, and transfer arguments to show that a power of the mod-4 \u27Bott element\u27 is induced by an Adams map
Aproximaci?n a la estimaci?n espacial de sequ?as meteorol?gicas en la cuenca hidrogr?fica del rio Coello, Colombia
15 p. Recurso Electr?nicoLa evaluaci?on espacio temporal para la caracterizaci?on de las sequ??as meteorol?ogicas se bas?o en datos de precipitaci
?on mensual acumulada entre 1996-2005 de 20 estaciones meteorol?ogicas distribuidas en la cuenca hidrogr?afica del r??o
Coello. Se realiz?o un preprocesamiento a los datos de precipitaci?on con pruebas de consistencia de datos para corregir y eliminar
datos sobre o sub estimados. Para estimar los datos faltantes de precipitaci?on se comparan tres m?etodos geoestad??sticos de interpolaci
?on, derivados de Kriging, asociados con variables secundarias como el Kriging Ordinario, CoKrigin Ordinario asocidadas a
las variables secundarias de un Modelo de Elevaci?on Digital y datos de precipitaci?on satelital TRMM. Para seleccionar el m?etodo
geoestad??stico se compar?o el ajuste de cada interpolaci?on con respecto a tres estaciones de referencia a trav?es de tres pruebas
de calidad, las cuales fueron Ra??z del Error Cuadr?atico Medio (RMSE), Criterio de Informaci?on de Akaike (AIC) y Criterio de
Informaci?on Bayesiano (BIC). En esta investigaci?on dos de tres pruebas favorecen al CoKriging Ordinario usando como variable
secundaria la Altitud (CoK+DEM). Con la serie interpolada de precipitaci?on se evaluaron y caracterizaron las sequ??as por medio
del ?Indice de Precipitaci?on Estandarizado (SPI) a escala mensual y trimestral, calculando los par?ametros de severidad, duraci?on,
intensidad y frecuencia de las sequ??as. Por medio de mapas se delimitaron las regiones en donde se presentan los valores negativos
de SPI. En el an?alisis espacio temporal los meses de Enero, Febrero, Julio y Agosto son los m?as secos del a?no. En el a?no
1997 se present?o la sequ??a meteorol?ogica de mayores afectaciones en la cuenca del r??o Coello generalmente concentrados en la
parte media y baja de la cuenca, con una intensidad maxima de -2,57 de SPI.
Palabras Clave: Sequ??a meteorol?ogica; m?etodos de interpolaci?on geoestad??sticos; ?Indice de Precipitaci?on Estandarizado
(SPI); par?ametros de sequ??as; cuenca hidrogr?afica del r??o Coello.The space-temporal evaluation to characterize meteorological droughts was based on data accumulated monthly
precipitation between 1996-2005 from 20 meteorological stations distributed in the Coello River basin. Data precipitation was
performed preprocessing with data consistency tests to correct and delete data over- or under estimated. To estimate missing
precipitation data are compared three geostatistical interpolation methods derived from Kriging, associated with secondary variables
such as the Ordinary Kriging, CoKrigin Ordinary associated with secondary variables of a Digital Elevation Model and
data satellite TRMM. To select the statistical method the setting of each interpolation was compared with respect to three reference
stations through three quality tests, which were Root Mean Square Error (RMSE), Akaike Information Criterion (AIC) and
Bayesian Information Criterion (BIC). In this investigation two of three tests favor the Ordinary CoKriging using as a secondary
variable Altitude (COK+DEM). With the interpolated series of precipitation were evaluated and characterized by drought Standardized
Precipitation Index (SPI) at monthly and quarterly scale, calculating the parameters of severity, duration, intensity and
frequency of droughts. By mapping are delimited the regions where occur the more negative values of SPI. In analyzing spacetemporal
the months of January, February, July and August are the driest of the year. In 1997 the meteorological drought greatest
damage occurs in the Coello River basin generally concentrated in the middle and lower part of the basin, with a maximum
intensity of SPI -2,57.
Keywords: Meteorological drought; geostatistical interpolation methods; Standardized Precipitation Index (SPI); parameters
droughts; Coello River Basin
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