1. A computer-readable information storage medium that stores a program for generating Hidden Markov Models to be used for speech recognition with a given speech recognition system, the information storage medium storing a program that renders a computer to function as: a scheduled-to-be-used model group storage section that stores a scheduled-to-be-used model group including a plurality of Hidden Markov Models scheduled to be used by the given speech recognition system; and a filler model generation section that generates Hidden Markov Models to be used as filler models by the given speech recognition system based on all or at least a part of the Hidden Markov Model group in the scheduled-to-be-used model group; wherein the filler model generation section classifies a plurality of probability density functions composing all or at least a part of the Hidden Markov Model group in the scheduled-to-be-used model group into a plurality of clusters, obtains a given parameter for defining probability density functions composing Hidden Markov Models to be used as filler models, based on the obtained probability density functions of each of the clusters.
1. A computer-readable information storage medium that stores a program for generating Hidden Markov Models to be used for speech recognition with a given speech recognition system, the information storage medium storing a program that renders a computer to function as: a scheduled-to-be-used model group storage section that stores a scheduled-to-be-used model group including a plurality of Hidden Markov Models scheduled to be used by the given speech recognition system; and a filler model generation section that generates Hidden Markov Models to be used as filler models by the given speech recognition system based on all or at least a part of the Hidden Markov Model group in the scheduled-to-be-used model group; wherein the filler model generation section classifies a plurality of probability density functions composing all or at least a part of the Hidden Markov Model group in the scheduled-to-be-used model group into a plurality of clusters, obtains a given parameter for defining probability density functions composing Hidden Markov Models to be used as filler models, based on the obtained probability density functions of each of the clusters. 4. The information storage medium according to claim 1 , wherein the filler model generation section classifies a plurality of probability density functions composing the Hidden Markov Model to be used as the filler model or its state into the same number of clusters as that of the probability density functions composing the Hidden Markov Model composing the scheduled-to-be-used model group or its state.