Neural Computation, Vol 9, 227-269, Copyright © 1997 by The MIT Press

REVIEWS

Probabilistic Independence Networks for Hidden Markov Probability Models

Padhraic Smyth, David Heckerman and Michael I. Jordan

Graphical techniques for modeling the dependencies of random variables have been explored in a variety of different areas, including statistics, statistical physics, artificial intelligence, speech recognition, image processing, and genetics. Formalisms for manipulating these models have been developed relatively independently in these research communities. In this paper we explore hidden Markov models (HMMs) and related structures within the general framework of probabilistic independence networks (PINs). The paper presents a self-contained review of the basic principles of PINs. It is shown that the well-known forward-backward (F-B) and Viterbi algorithms for HMMs are special cases of more general inference algorithms for arbitrary PINs. Furthermore, the existence of inference and estimation algorithms for more general graphical models provides a set of analysis tools for HMM practitioners who wish to explore a richer class of HMM structures. Examples of relatively complex models to handle sensor fusion and coarticulation in speech recognition are introduced and treated within the graphical model framework to illustrate the advantages of the general approach.

This article has been cited by other articles:

				Z. Ghahramani and G. E. Hinton Variational Learning for Switching State-Space Models Neural Comput., April 1, 2000; 12(4): 831 - 864. [Abstract] [Full Text]

				Y. Weiss Correctness of Local Probability Propagation in Graphical Models with Loops Neural Comput., January 1, 2000; 12(1): 1 - 41. [Abstract] [Full Text]