1. School of Economics and Management; Chang'an University; Xi'an; China
2. Old Dominion University; Norfolk; VA; USA
3. Department of Engineering; Indiana University Purdue University Fort Wayne; Fort Wayne; IN; USA
4. Safety Engineering Department, College of Engineering; Warmia and Mazury University at Olsztyn; Olsztyn; Poland
5. School of Economics and Management; Beijing Jiaotong University; Beijing; China