1. Department of Statistics, National Cheng Kung University, Tainan 701, Taiwan
2. Department of Statistics, North Carolina State University, Raleigh, NC 27695, USA
3. Institute of Epidemiology and Preventive Medicine, National Taiwan University, Taipei 100, Taiwan
4. Bioinformatics Research Center, North Carolina State University, Raleigh, NC 27695, USA
5. Department of Biostatistics, University at Buffalo, Buffalo, NY 14214, USA