1. School of Business, Suzhou University of Science and Technology, Suzhou, Jiangsu, China
2. School of Mathematics and Computer Science, Guilin University of Electronic Technology, Guilin, Guangxi, China
3. College of Science, China University of Petroleum, Qingdao, Shandong, China
4. School of Engineering and Applied Science, Western Kentucky University, Bowling Green, KY, USA
5. School of Economics and Management, China University of Petroleum, Qingdao, Shandong, China