1. School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu, China, and the Faculty of Information Technology, Jyvaskylan yliopisto, 4168 Jyvaskyla, Keski-Suomi, Finland
2. School of Computer Science and Engineering, University of Electronic Science and Technology of China, Chengdu, China
3. Southeast University, 12579 Nanjing, Jiangsu, China
4. Department of Computer Science, University of Exeter, Exeter, Exeter, United Kingdom of Great Britain and Northern Ireland
5. Electrical Engineering Department, Ecole de technologie superieure, 14849 Montreal, Quebec, Canada, H3C 1K3
6. Electrical Engineering, Ecole de technologie superieure, 14849 Montreal, Quebec, Canada