The aim of this paper is to apply the appropriate numerical, statistical and computer techniques to the construction of approximate solutions to nonlinear 2nd order stochastic differential equations modeling some engineering systems subject to large random external disturbances. This provides us with quantitative results on their asymptotic behavior.
The aim of this paper is to demonstrate how the appropriate numerical, statistical and computer techniques can be successfully applied to the construction of approximate solutions of stochastic differential equations modeling some engineering systems subject to large disturbances. In particular, the evolution in time of densities of stochastic processes solving such problems is discussed.
A formula for evaluation of the distribution of a linear combination of independent inverted gamma random variables by one-dimensional numerical integration is presented. The formula is direct application of the inversion formula given by Gil–Pelaez [gil-pelaez]. This method is applied to computation of the generalized -values used for exact significance testing and interval estimation of the parameter of interest in the Behrens–Fisher problem and for variance components in balanced mixed linear...
La cartografía de enfermedades infecciosas en periodos sucesivos plantea la necesidad de su extensión al caso dinámico. En este trabajo proponemos la concatenación temporal de modelos auto-regresivos espaciales para abordar el análisis de mortalidad por meningitis en España en el período 1950-1990 con datos agregados a nivel provincial. Para la estimación v selección del modelo usamos técnicas basadas en la función de verosimilitud.
Data depth is an important concept of nonparametric approach to multivariate data analysis. The main aim of the paper is to review possible applications of the data depth, including outlier detection, robust and affine-equivariant estimates of location, rank tests for multivariate scale difference, control charts for multivariate processes, and depth-based classifiers solving discrimination problem.
Cette étude offre une large vision de synthèse prospective ; mais aussi, des résultats techniques précis sur une famille très générale que nous avons élaborée de coefficients d'association entre variables descriptives relationnelles à partir de leur observation empirique sur un ensemble O d'objets élémentaires. Un même coefficient est obtenu à partir d'une forme de normalisation statistique par rapport à une hypothèse d'absence de liaison, d'un indice brut d'association. Ce dernier suppose une représentation...
Cette étude offre une large vision de synthèse prospective : mais aussi, des résultats techniques précis sur une famille très générale que nous avons élaborée de coefficients d'association entre variables descriptives relationnelles à partir de leur observation empirique sur un ensemble O d'objets élémentaires. Un même coefficient est obtenu à partir d'une forme de normalisation statistique par rapport à une hypothèse d'absence de liaison, d'un indice brut d'association. Ce dernier suppose une représentation...
The paper briefly reviews recent advances in the methodology of feature selection (FS) and the conceptual base of a consulting system for solving FS problems. The reasons for designing a kind of expert or consulting system which would guide a less experienced user are outlined. The paper also attempts to provide a guideline which approach to choose with respect to the extent of a priori knowledge of the problem. The methods discussed here form the core of the software package being developed for...
We consider here a multivariate sample Xj = (X1.j > ... > Xi.j), 1 ≤ j ≤ n, where the Xj, 1 ≤ j ≤ n, are independent i-dimensional extremal vectors with suitable unknown location and scale parameters λ and δ respectively. Being interested in linear estimation of these parameters, we consider the multivariate sample Zj, 1 ≤ j ≤ n, of the order statistic of largest values and their concomitants, and the best linear unbiased estimators of λ and δ based on such multivariate sample. Computational...
The paper presents a new methodology to obtain partially sequential truncated tests which are optimum in the sense of minimizing the maximum expected sample number. This methodology is based on a variational approach and uses the Lagrange multipliers technique in order to obtain necessary conditions for a test to be optimum. By means of these conditions the optimum test can be obtained. Finally, the method is applied to the problem of testing the mean of an exponential distribution. As a particular...
2000 Mathematics Subject Classification: 62F25, 62F03.A two-sided conditional confidence interval for the scale parameter θ of a Weibull distribution is constructed. The construction follows the rejection of a preliminary test for the null hypothesis: θ = θ0 where θ0 is a given value. The confidence bounds are derived according to the method set forth by Meeks and D’Agostino (1983) and subsequently used by Arabatzis et al. (1989) in Gaussian models and more recently by Chiou and Han (1994, 1995)...
Conditions for bimodality of mixtures of two unimodal distributions are investigated in some special cases. Based on general characterizations, explicit criteria for the parameters are derived for mixtures of two Cauchy, logistic, Student, gamma, log-normal, Gumbel and other distributions.