1. Department of Mathematical Statistics, School of Statistics, Shandong University of Finance and Economics, Jinan, China
2. Ph.D. Program in Computer Science, The Graduate Center, The City University of New York, New York, NY, USA
3. Department of Statistics, Columbia University, New York, NY, USA
4. Department of Biostatistics, School of Public Health, Shandong University, Jinan, China
5. Department of Computer Science, Hunter College, The City University of New York, NY, USA