1. College of Information Science and Engineering, Chengdu University, Chengdu 610106, P. R. China
2. Key Laboratory of Pattern Recognition and Intelligent, Information Processing, Chengdu 610106, P. R. China
3. College of Computer Science, Chengdu Normal University, Chengdu 611130, P. R. China
4. Institute of Intelligent Computing and Information Technology, Chengdu Normal University, Chengdu 611130, P. R. China