出典:Wikipedia
出典:『Wikipedia』 (2011/05/22 14:52 UTC 版)
The inside-outside algorithm is a way of re-estimating production probabilities in a probabilistic context-free grammar. It was introduced by James K. Baker in 1979 as a generalization of the forward-backward algorithm for parameter estimation on hidden Markov models to stochastic context-free grammars. It is used to compute expectations, for example as part of the Expectation-maximization algorithm (an unsupervised learning algorithm).