Influence of Voice Delay on Human Perception of Group Synchronization Error for Remote Learning : One-way Communication Case

This paper clarifies the influence of the voice delay on human perception of group synchronization error in remote learning by subjective assessment. In our assessment, we produce the difference in output timing of lecture video between a teacher terminal and a student terminal. Each subject as a student observes the output timing relation (i.e., group synchronization) between the lecture video and teacher's voice, and then the subject answers whether he/she perceives the group synchronization error or not. We also examine the influence of difference in voice contents on the error. Assessment results demonstrate that the perception rate depends on the group synchronization error plus the voice delay, and all the subjects can hardly perceive group synchronization errors (plus voice delays) less than or equal to about 250 ms. We further illustrate that the perception rate depends on the voice contents.