Résumé :
The Cross-Entropy method is
a new Monte
Carlo paradigm pioneered by Rubinstein (1999) in Operation Research.
Its primary
applications are (i) the calculation of probability of rare events, and
(ii) the optimisation of irregular, multi-modal functions.
While these two objectives seem to have a little in common, the CE
approach manages to express them in a similar framework.
In this talk, we will
explain how Statistics can benefit from the CE method, and how the CE
method can also benefit in turn from Statistical methodology. We will
discuss the following particular applications in Statistics:
Monte-Carlo p-values, simulation of truncated distributions, variable
selection, and mixture estimation. We will see that in each case CE
provides significant improvements over current methods. Interestingly,
we will see also vanilla CE rarely works directly, but tandard tools
from Statistical Inference allow for developing more efficient
algorithms. In particular, we will discuss a CE-EM algorithm for
mixture estimation, which outperform any straight CE or EM algorithm,
in terms, of finding higher modes of the likelihood function.