1. Institute of Statistics and Applied Mathematics, Anhui University of Finance and Economics, Bengbu, Anhui, China
2. Shanghai Key Laboratory of Intelligent Information Processing, School of Computer Sciences, Fudan University, Shanghai, China
3. Department of Mathematics, University of Paris VIII, Saint-Denis, France
4. Mathematics and Science College, Shanghai Normal University, Shanghai, China
5. Temasek Laboratories, National University of Singapore, Singapore
6. School of Mathematics and Physics, University of South China, Hengyang, Hunan, China