“…With such knowledge, many studies have developed models for predicting actual turn-changing, i.e., whether turn-changing or turn-keeping will take place, on the basis of acoustic features [3, 6, 10, 12, 18, 26, 34, 36ś38, 43, 47, 50], linguistic features [34,37,38,43], and visual features, such as overall physical motion [3,6,8,43] near the end of a speaker's utterances or during multiple utterances. Moreover, some research has focused on detailed non-verbal behaviors such as eye-gaze behavior [3,6,18,20,24,26], head movement [18,21,22], mouth movement [23], and respiration [20,25].…”