A field experiment on the effect of sound absorption on acclimation of new children to kindergarten—Part 2: Estimating children's crying by acoustic event detection

A field experiment was conducted where sound absorbing materials were temporarily installed in actual kindergarten classrooms to examine the effect of sound absorption on acclimation of new children to kindergarten. There were two classrooms for two 2-year-old groups and sound absorbing material was temporarily installed in one of the two rooms. Since children who have just entered kindergarten often cry because they do not want to be there, the time ratio at which children were crying was analyzed in Part 1 judging based on recorded video and sound, which required much time and labor. Therefore, this study attempted to employ an acoustic event detection method using Mel-Frequency Cepstral Coefficients (MFCC) features in the analysis. The training data consisted of 1180 2-s sound segments recorded in the classroom on five days, and then 400 2-s segments consisted of 200 sounds each judged by human to be crying or non-crying, recorded on different 14 days than the training data, were analyzed to compare human and computer judgments. The result showed that 153/200 segments were judged to be crying and 183/200 were judged not to be crying by computer, indicating a good correspondence.