(1.School of Information Science and Technology,Southwest Jiaotong University,Chengdu 611756;
2.National-Local Joint Engineering Laboratory of System Creditability Automatic Verification,
Southwest Jiaotong University,Chengdu 611756;
3.School of Mathematics,Southwest Jiaotong University,Chengdu 611756;
4.School of Computer and Artificial Intelligence,Southwest Jiaotong University,Chengdu 611756,China)