169 research outputs found
Políticas para la integración del juicio experto y los pronósticos estadísticos en el marco organizacional
Ha sido ampliamente reconocida la importanciade la predicción en la tomade decisiones, y se han encontrado evidenciasde que uno de los métodos másefectivos es el ajuste de los pronósticosobtenidos a partir de modelos matemáticosusando juicios informados. Noobstante, existe una amplia cantidadde factores que pueden afectar la calidady credibilidad de las predicciones;en este trabajo se examinan aquellosfactores relacionados con las políticasorganizacionales, y se proponen variasestrategias para su mitigación.Predicción, Estrategia Organizacional,Juicio Experto, ModeladoMatemático
Tendencias en la predicción y estimación de los intervalos de confianza usando modelos de redes neuronales aplicados a series temporales
En este artículo, se discute el estado del arte en la estimación de la predicción varios pasos adelante para modelos de series temporales no lineales basados en perceptrones multicapa. Se revisan las principales tendencias para la estimación de pronósticos puntuales e intervalos de confianza. En adición, se argumenta sobre los principales problemas abiertos para investigación futura en la predicción de series temporales usando redes neuronales
Finite size effects and non-additivity in the van der Waals interaction
We obtain analytically the exact non-retarded dispersive interaction energy
between an atom and a perfectly conducting disc. We consider the atom in the
symmetry axis of the disc and assume the atom is predominantly polarizable in
the direction of this axis. For this situation we discuss the finite size
effects on the corresponding interaction energy. We follow the recent procedure
introduced by Eberlein and Zietal together with the old and powerful
Sommerfeld's image method for non-trivial geometries. For the sake of clarity
we present a detailed discussion of Sommerfeld's image method. Comparing our
results form the atom-disc system with those recently obtained for an atom near
a conducting plane with a circular aperture, we discus the non-additivity of
the van der Waals interactions involving an atom and two complementary
surfaces. We show that there is a given ratio z/a between the distance z from
the atom to the center of the disc (aperture) and the radius of the disc a
(aperture) for which non-additivity effects vanish. Qualitative arguments
suggest that this quite unexpected result will occur not only for a circular
hole, but for anyother symmetric hole.Comment: 8 page
Image method in the calculation of the van der Waals force between an atom and a conducting surface
Initially, we make a detailed historical survey of van der Waals forces,
collecting the main references on the subject. Then, we review a method
recently proposed by Eberlein and Zietal to compute the dispersion van der
Waals interaction between a neutral but polarizable atom and a perfectly
conducting surface of arbitrary shape. This method has the advantage of
relating the quantum problem to a corresponding classical one in electrostatics
so that all one needs is to compute an appropriate Green function. We show how
the image method of electrostatics can be conveniently used together with the
Eberlein and Zietal mehtod (when the problem admits an image solution). We then
illustrate this method in a couple of simple but important cases, including the
atom-sphere system. Particularly, in our last example, we present an original
result, namely, the van der Waals force between an atom and a boss hat made of
a grounded conducting material.Comment: This is a pedagogical and introductory paper on van der Waals forces
between an atom and a conducting surfac
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