1. School of Management, South China Business College, Guangdong University of Foreign Studies, Guangzhou 510545, GuangDong, P. R. China
2. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology Kunming 650093, Yunnan, P. R. China
3. Faculty of Megadate and Computing, Guangdong Baiyun University, Guangzhou 510450, GuangDong, P. R. China