Turn-taking patterns in human discourse and their impact on group communication service design

Recent studies demonstrated the benefit of integrating speaker prediction features into the design of group-communication services supporting multiparty online discourse. This paper aims at delivering a more elaborate analysis of speaker prediction by analyzing a larger volume of data. Moreover, it tests the existence of speakers dominating speaking time. Towards this end, we analyze tens of hours of recorded meeting and lecture sessions. Our principal results for meeting-like interaction manifest that the next speaker is one of the last four speakers with over 90% probability. This is seen consistently across our data with little variance (standard deviation of 8.71%) independent of the total number of potential speakers. Furthermore, lecture time is in most cases significantly dominated by the tutor. In meetings, although a single dominating speaker is always evident, domination exhibited high variability. Generally, our findings strengthen and further motivate the act of incorporating user-beha vior awareness into group communication service desig

Dynamic Adaptation of Source Specific Distribution Trees for Multiparty Teleconferencing

Content distribution is becoming increasingly important with the decreasing cost of broadband access and the growing number of Internet users. Many of today’s content distribution applications require a group communication infrastructure. Source-Specific Multicast (SSM) constitutes a promising alternative to the slow takeoff of multicast as a ubiquitous service, whether at the network- or application layer. Still, implementing any-source functionality on top of SSM remains an interesting research topic. In this paper we present how application semantics can be applied to multi-source distribution over source-specific trees. Specifically, we present two novel tree management methods that incorporate application semantics and evaluate them through simulations against the state of the art. The evaluation results manifest that our methods significantly improve perceived quality of service in the multi-source sessions we consider