1. School of Computer Science and Engineering, Xi'an University of Technology, Xi'an, China
2. Guangzhou Institute of Technology, Xidian University, Guangzhou, China
3. Department of Electronic Engineering, Tsinghua University, Beijing, China
4. Department of Electrical and Computer Engineering, University of Windsor, Windsor, ON, Canada
5. Department of Sciences and Informatics, Muroran Institute of Technology, Muroran, Japan
6. School of Computer Science, University of Oklahoma, Norman, OK, USA
7. School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing, China