1. Epidemiology and Statistics; School of Public Health; Jilin University; Changchun Jilin China
2. Key Laboratory of Radiobiology (Ministry of Health); School of Public Health; Jilin University; Changchun China
3. Department of Statistics; University of Manitoba; Winnipeg Canada
4. The First Hospital of Jilin University; Changchun China
5. School of Mathematics and Statistics; Northeast Normal University; Changchun Jilin China