1. School of economics and management, Shangqiu Normal University, Shangqiu, P. R. China
2. School of Information and Control Engineering, LiaoNing Petrochemical University, Fushun, P. R. China
3. Monmouth University, West Long Branch, New Jersey, USA
4. College of Information Science and Engineering, Northeast University, Shenyang
5. Department of Computer Science and Technology, Shandong University of Science and Technology, Qingdao