This article creates a general class of perturbation models which are described by an underlying null model that accounts for most of the structure in data while a perturbation accounts for possible small localized departures. The goal is to develop theory and inferential methods for fitting the perturbation models including the general case when the null model contains a set of nuisance parame...

ABSTRACT Macrosegregation has been received high attention in the solidification modeling studies. In the present work, a numerical model was developed to predict the macrosegregation during the DC Casting of an Al-4.5wt%Cu billet. The mathematical model developed in this study consists of mass, momentum, energy and species conservation equations for a two-phase mixture of liquid and solid in a...

The present paper reports the results of an extensive numerical analysis of electromagnetic fields in random dielectric materials. The effective permittivity of a two-dimensional (2-D) dielectric mixture is calculated by FDTD simulations of such a sample in a TEM waveguide. Various theoretical bounds are tested in light of the numerical simulations. The results show how the effective permittivi...

In this study, convection flow in microchannel heat sink with offset fan-shaped reentrant cavities in sidewall filled with Fe3O4-water is numerically investigated. The effects of changing some parameters such as Reynolds number and magnetic field are considered. The nanofluid flow is laminar, steady and incompressible, while the thermo-physical properties of nanoparticles were assumed constant....

This paper presents the use of a finite mixture model for multi-look polarimetric SAR image analysis. The pixels are complex covariance matrices set as a G p mixture distribution. The parameters are estimated with the SEM algorithm Experimental results on real SAR data are reported, showing that a careful statistical model is important.

This work investigates a combined stochastic and deterministic optimization approach for multivariate mixture density estimation. Mixture probability density models are selected and optimized by combining the optimization characteristics of a multiagent stochastic optimization algorithm based on evolutionary programming and the expectation-maximization algorithm. Unlike the traditional finite m...

Current speaker recognition applications involve the authentication of users by their voices for access to restricted information and privileges. The speech signal is often transmitted to the recognizer through communication channels presenting different transmission characteristics. The aim of this paper is to study the effects of speech bandwidth and coding schemes on speaker verification. We...