1. School of Computer and Information Science, Southwest University, Chongqing, China
2. School of Informationand Electronics, Beijing Institute of Technology, Beijing, China
3. Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
4. Renming University of China, China
5. Xidian University, China
6. Department of Electrical and Computer Engineering, Auburn University, Auburn, USA