presents
Michael Levine
of Purdue
Maximum Smoothed Nonparametric Likelihood for Multivariate Mixtures
Abstract
Finite mixtures of nonparametric components represent a new and
important area of statistical research. In this talk, we introduce an
EM-type algorithm for estimation of these mixtures. The observations
are assumed to be multidimensional. Coordinates of observations are
assumed to be independent conditional on knowing which component they
came from. The algorithm is designed for any number of components and
any number of dimensions. As opposed to an earlier algorithm of
Benaglia, Chauveau and Hunter (2009), this algorithm has an explicit
objective function that it maximizes. Moreover, it also possesses a
verifiable ascent property with respect to that objective function.
The approach we use to construct this algorithm is based on the
so-called regularization argument of Eggermont and LaRiccia, first
introduced in their series of papers on *mixing density* estimation in
1990’s. We apply a similar approach to the problem of nonparametric
estimation of *finite mixtures. * To the best of our knowledge, this
is the first true EM-type algorithm that can fit a mixture of an
arbitrary number of multivariate nonparametric components. Extensive
simulations demonstrate an excellent performance of the new algorithm
in a variety of situations.
Friday, April 23, 2010
3:00pm - 4:00pm
2203 SAS Hall