Ruiji Fu is a PhD candidate at Harbin Institute of Technology (HIT), China. He received his MS and BS both in Computer Science from HIT, in 2009 and 2007 respectively. His research interests include natural language processing, text mining, and open information extraction. Bing Qin received her PhD in computer science from Harbin Institute of Technology (HIT), China in 2005. She is a full professor in the School of Computer Science and Technology, HIT. Her research interests include natural language processing, text mining, and opinion mining. Ting Liu received his PhD in computer science from Harbin Institute of Technology (HIT), China in 1998. He is a full professor in the School of Computer Science and Technology, HIT. His current research interests include natural language processing, informa- tion retrieval, and social computing.E-mail: (rj fu,bqin,tliu) @ir.hit.edu.cn