1. School of Information and Software Engineering, University of Electronic Science and Technology of China, Chengdu, People's Republic of China
2. School of Mathematical Sciences, University of Electronic Science and Technology of China, Chengdu, People's Republic of China
3. College of Mathematics and Statistics, Guangxi Normal University, Guilin, People's Republic of China
4. College of Automation and Electronic Engineering, Qingdao University of Science and Technology, Qingdao, People's Republic of China
5. School of Electrical Engineering and Electronic Information, Xihua University, Chengdu, People's Republic of China