2011 年 13 巻 1 号 p. 23-30
A large network delay is likely to obstruct human interaction in telecommunication systems such as telephony or video conferencing systems. In spite of the extensive investigations that have been carried out on network delays of voice and image data, there have been few studies regarding support for embodied communication under the conditions of network delay. To maintain smooth human interaction, it is important that the various ways in which delay is manifested are understood. We have already developed an embodied virtual communication system that uses an avatar called "VirtualActor," in which speakers who are remotely located from one another can share embodied interaction in the same virtual space. Responses to a questionnaire that was used in a communication experiment confirmed that a fixed 500-ms network delay has no effect on interactions via VirtualActors. In this paper, we propose a method of presenting a speaker's voice and an avatar's motion feedback in the case of a 1.5-s network delay using VirtualActors. We perform two communication experiments under different conditions of network delay. The aim of the first experiment is to examine the effect of a random time delay on the conversation. The second experiment is conducted under the conditions of a free-form conversation that takes place in 5 scenarios-1 real-time scenario without a network delay and 4 scenarios with network delay that involve a combination of a delay in the talker's voice and in his/her avatar's motion feedback. The subjects consisted of a total of 30 students who worked in 15 pairs and who were familiar with each other. A sensory evaluation shows the effects upon communication of delays in the avatar's motion feedback, from the viewpoint of supporting the interaction.
