September 22-25, 1997
The results of our research presented in this paper are two-fold. First, an estimation of global posteriors is formalized in the framework of hybrid HMM/ANN systems. It is shown that hybrid HMM/ANN systems, in which the ANN part estimates local posteriors, can be used to modelize global model posteriors. This formalization provides us with a clear theory in which both REMAP and "classical" Viterbi trained hybrid systems are uni_ed. Second, a new forward- backward training of hybrid HMM/ANN systems is derived from the previous formulation. Comparisons of performance between Viterbi and forward- back- ward hybrid systems are presented and discussed.
Bibliographic reference. Hennebert, J. / Ris, Christophe / Bourlard, Hervè / Renals, Steve / Morgan, Nelson (1997): "Estimation of global posteriors and forward-backward training of hybrid HMM/ANN systems", In EUROSPEECH-1997, 1951-1954.