EM algorithms for multivariate normal mixture decomposition have been recently proposed in order to maximize the likelihood function in a constrained parameter space having no singularities and a reduced number of spurious local maxima. However, such approaches require some a priori information about the eigenvalues of the covariance matrices. The behavior of the EM algorithm near a degenerated solution is investigated. The obtained theoretical results would suggest a new kind of constraint based on the dissimilarity between two consecutive updates of the eigenvalues of each covariance matrix. The performances of such a ‘‘dynamic’’ constraint are evaluated on the grounds of some numerical experiments.
|Titolo:||Degeneracy of the EM algorithm for the MLE of multivariate Gaussian mixtures and dynamic constraints|
|Autori interni:||INGRASSIA, Salvatore|
|Data di pubblicazione:||2011|
|Rivista:||COMPUTATIONAL STATISTICS & DATA ANALYSIS|
|Appare nelle tipologie:||1.1 Articolo in rivista|