In this section, an experiment dealing with data segmentation is presented. The correct phoneme sequence for each segment of the speech data is known but the correct segmentation, i.e. the times of the transitions between the phonemes, is not. Therefore it is reasonable to see whether the model can learn to find the correct segmentation.
The HMM used in this experiment had four states for each phoneme of the data. These states were linked together in a chain. Transitions from ``outside'' were allowed only to the first state and then forward in the chain until the last internal state of the phoneme was reached. This is a standard procedure in speech recognition to model the duration of the phonemes.