中文摘要：

HAIV Wenwen, Ph.D. candidate at State Key Labora- tory of Networking and Switching Technology at Beijing University of Posts and Telecommunications, China. Her research interests include data mining, opinion analysis, user behaviour analysis, natural language processing. QUE Xirong, Associate Professor of State Key Labo- ratory of Networking and Switching Technology at Beijing University of Posts and Telecommunications （BUPT）, China. She received her bachelor degree and master degree in computer science from BUPT in 1993 and 1998, respectively. Her research interests include IP QoS, next generation internet services and novel network architectures. SONG Siqi, is currently an M.S. candidate at State Key Laboratory of Networking and Switching Technology in Beijing University of Posts and Telecommunications, China. His research interests include crawler techniques, emerging topic detection, and social network analysis. TIAN Ye, Ph.D. candidate at State Key Laboratory of Networking and Switching Technology in Beijing University of Posts and Telecommunications, China His research interests include data mining, social network analysis and topic propagation. WANG Wendong, Professor of State Key Laboratory of Networking and Switching Technology at Beijing University of Posts and Telecommunications （BUPT）, China. He received his B.S. and MS. degrees in com- puter science from BUPT, China in 1985 and 1991, respectively. His research interests include IP QoS, next generation internet services and novel network architectures. ＊The corresponding author. Email： wd- wang@bupt.edu.cn