School of Computer Science and Technology, Heilongjiang University, Harbin, China.|School of Computer Science and Technology, Heilongjiang University, Harbin, China.|School of Mathematical Science, Heilongjiang University, Harbin, China.|School of Computer Science, Beijing University of Posts and Telecommunications, Beijing, China.|School of Computer Science and Technology, Heilongjiang University, Harbin, China.|School of Computer Science and Technology, Heilongjiang University, Harbin, China.