1. a School of Management, Wuhan Institute of Technology, Wuhan, Hubei 430205, China
2. b Higher Vocational College, Shaanxi Institute of International Business, Xi'an, Shaanxi 712000, China
3. c Port Office, Shangluo Government of the People's Republic of China, Shangluo, Shaanxi 726000, China
4. d School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China