1. School of Electronic Information Engineering, Southwest University, Chongqing, P.R. China
2. School of Mathematics and Statistics, Chongqing Three Gorges University, Chongqing, P.R. China
3. State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, P.R. China
4. Department of Mathematics, Texas A & M University at Qatar, Doha, Qatar