1. College of Computer Science, Sichuan Normal University, Chengdu, China
2. State Key Laboratory of Integrated Service Networks, Xidian University, Xi’an, China
3. Department of Electrical and Computer Engineering, University of Windsor, Windsor, Canada
4. School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu, China
5. Department of Systems and Computer Engineering, Carleton University, Ottawa, Canada
6. College of Computer Science and Software Engineering, Shenzhen University, Shenzhen, China