1. College of Bioinformatics Science and Technology, Harbin Medical University, Harbin 150081, China
2. Department of Mathematics, Heilongjiang Institute of Technology, Harbin 150050, China
3. Department of Computer Science and Technology, Heilongjiang University, Harbin 150080, China
4. Department of Medical Informatics, Harbin Medical University, Daqing Campus, Daqing 163319, China