LI Zhanshan1,2, HAN Wencheng1,2, LI Hongbo1,2, WANG Tao3
1. Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education, Jilin University,Changchun 130012, China|2. College of Computer Science and Technology, Jilin University, Changchun 130012, China;3. School of Computer Science and Engineering, Changchun University of Technology, Changchun 130012, China