As can be seen from the confusion matrices shown in Figure 4, DAH-CRF+LDA utt gives improvement over SAH-CRF for all the four DA classes of DyDA.
it is not surprising that SAH-CRF makes poor prediction on the utterances of these two DAs: they share many syntactic cues, e.g., indicator words such 'okay', 'oh', and 'uh-huh', which can easily confuse the model.