1. College of Computer Science and Technology, China University of Petroleum (East China), Qingdao, China
2. School of Software, Nanjing University of Information Science and Technology, Nanjing, China
3. School of Computer and Electronic Information, Nanjing Normal University, Nanjing, China
4. School of Computing and Communications, Lancaster University, Lancaster, U.K
5. School of Computer Science and Engineering and State Key Laboratory of Software Development Environment, Beihang University, Beijing, China
6. Department of Computing, Macquarie University, Macquarie Park, NSW, Australia