1. School of Statistics and Mathematics, Central University of Finance and Economics, Beijing, China
2. China UnionPay Post-Doctoral Research Station, Shanghai, China
3. Postdoctoral Research Station of Computer Science and Technology, Fudan University, Shanghai, China
4. Facebook, Inc., Menlo Park, CA
5. Department of Statistics and Actuarial Science, University of Hong Kong, Hong Kong
6. Guanghua School of Management, Peking University, Beijing, China