1. School of Mathematics and Statistics, Henan University of Science and Technology, Luoyang, Henan 471023, P. R. China
2. Longmen Laboratory, Luoyang, Henan 471003, P. R. China
3. Guizhou Key Laboratory of Economics System Simulation, Guizhou University of Finance and Economics, Guiyang, Guizhou 550004, P. R. China