1. State Key Laboratory of Integrated Service Networks, Xidian University, Xi’an, China
2. College of Information Engineering, Northwest A&F University, Yangling, China
3. Southwest China Research Institute of Electronic Equipment, Chengdu, China
4. School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou, China
5. Information Systems Technology and Design Pillar, Singapore University of Technology and Design, Tampines, Singapore