BP for categorization...relative frequency problem

[Jim Hendler]

Herve Bourlard and Nelson Morgan had to deal with this problem in
a system being used in the context of continuous speech recognition.
They solved the problem, to some extent, by dividing the output
category strengths by the prior probabilities of the training set.  This
avoided having to do anything terribly tricky in the network, and let
them use classical back-propagation without extension (although I think
they've also used some recurrences in one version).  I know there
have been several nice publications of their work in speech - various
papers with the authors Bourlard, Wellekens, and Morgan in various
combinations.  Morgan is at ICSI, and is probably the most accessible
of these authors for requesting reprints.
 -Jim Hendler
 UMCP