1. School of Control Engineering, Northeastern University at Qinhuangdao, Qinhuangdao, China
2. College of Information Science and Engineering, Northeastern University, Shenyang, China
3. School of Computer and Communication Engineering, Northeastern University at Qinhuangdao, Qinhuangdao, China
4. Division of Information Systems, University of Aizu, Fukushima, Japan