1. School of Information and Control Engineering Qingdao University of Technology Qingdao Shandong P.R. China
2. School of Engineering Qufu Normal University Rizhao Shandong P.R. China
3. School of Electrical and Information Engineering Anhui University of Technology Maanshan P.R. China
4. School of Information Science and Engineering Chengdu University Chengdu P.R. China