1. Key Laboratory for Nonlinear Science and System Structure , Chongqing Three Gorges University , Chongqing , 404000 , P.R.China
2. Research Center for Mathematics and Economics , Tianjin University of Finance and Economics , Tianjin , 300222 , P.R.China
3. College of Computer Science and Technology , Chongqing University of Posts and Telecommunications , Chongqing , 400065 , P.R.China
4. School of Mathematics and Statistics , Changsha University of Science and Technology , Changsha , 410114, Hunan , P.R. China
5. School of Mathematics and Computational Science , Xiangtan University , Xiangtan , 411105, Hunan , P.R.China