Wei-Feng Pan is now a Ph.D. candidate of State Key Laboratory of Software Engineering (SKLSE) at Wuhan University. He is a CCF member. His current research interests include software metrics, soft-ware evolution, and interdisciplinary research between software engineering and complex networks. Corresponding Author Bing Li, CCF senior member, is now a professor and Ph.D. supervisor of SKLSE at Wuhan University. He worked as a postdoctoral researcher in SKLSE at Wuhan University from 2003 to 2005. And he received his Ph.D., M.S. and B.A. degrees from Huazhong University of Science and Technology (HUST) in 2003, 1997 and 1990 respectively, all in computer science. His main research interests include requirements engineering, complex network, and semantic Web service. Yu-Tao Ma is now a lecturer of SKLSE at Wuhan University as well as a post-doctor researcher of Institute of Electronic System Engineering. He is both CCF and ACM member. He received the Ph.D. de- gree from Wuhan University in 2007. His current research interests include software metrics, software evolution and the interdisciplinary research between software engineering and complex networks. Ye-Yi Qin is an M.S. candidate of SKLSE at Wuhan University. Her research interests include soft-ware engineering and complex networks. Xiao-Yan Zhou is an M.S. candidate of SKLSE at Wuhan University. Her research interests include software engineering and complex networks.