1. College of Artificial Intelligence, Southwest University, Chongqing, P.R. China
2. Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Canada
3. Key Laboratory of Computational Intelligence and Chinese Information Processing of Ministry of Education, and the School of Computer and Information Technology, Shanxi University, Taiyuan, P.R. China
4. School of Information Science and Technology, Nantong University, Nantong, P.R. China
5. School of Mathematics and Statistics, Southwest University, Chongqing, P.R. China