报告人：徐跃东博士

主持人：张卫教授

时间： 2013年1月8日上午10点

地点：闵行校区信息楼629会议室

报告摘要：The Quality of Experience (QoE) of streaming service is often degraded by frequent playback interruptions. To mitigate the interruptions, the media player prefetches streaming contents before starting playback, at a cost of delay. We study the QoE of streaming from the perspective of flow dynamics. First, a framework is developed for QoE when streaming users join the network randomly and leave after downloading completion. We compute the distribution of prefetching delay using partial differential equations (PDEs), and the probability generating function of playout buffer starvations using ordinary differential equations (ODEs) for CBR streaming. Second, we extend our framework to characterize the throughput variation caused by opportunistic scheduling at the base station, and the playback variation of VBR streaming. Our study reveals that the flow dynamics is the fundamental reason of playback starvation. The QoE of streaming service is dominated by the first moments such as the average throughput of opportunistic scheduling and the mean playback rate. While the variances of throughput and playback rate have very limited impact on starvation behavior.

报告人简介： Dr. XU Yuedong is now a postdoc of The Chinese University of Hong Kong, and was a previous postdoc of INRIA (in conjunction with Universite d'Avignon), France. He received his PHD degree from Department of Computer Science & Engineering, The Chinese University of Hong Kong in 2009. Before that, he obtained his master degree from Huazhong University of Science and Technology with honors and bachelor degree from Anhui University. Dr. XU’s research interests are broadly in the areas of computer networks such as video streaming, content distribution, cloud computing and network economics.