WANG Hai-yan1,2,3,OUYANG Dan-tong1,2,ZHANG Yong-gang1,2,YANG Ming-ming 1,2
(1.College of Computer Science and Technology, Jilin Univ, Changchun,Jilin130012, China; 2.Key Laboratory of Symbolic Computation and Knowledge Engineering for Ministry of Education, Jilin Univ, Changchun,Jilin130012, China; 3. College of Computer, Jilin Normal Univ, Siping,Jilin136000, China)