Corresponding Author

Department of Statistics and Finance, School of Management, University of Science and Technology of China, Hefei, Anhui, People's Republic of China

Correspondence Hong Zhang, Department of Statistics and Finance, School of Management, University of Science and Technology of China, Hefei, 230026 Anhui, People's Republic of China.

Email: zhangh@ustc.edu.cn

Jinbo Chen, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.

Email: jinboche@mail.med.upenn.edu