About the Authors

Shifeng Han

Roles Investigation, Methodology, Writing – original draft, Writing – review & editing

hanshifeng0630@hotmail.com

Affiliation School of Management and Economics, Beijing Institute of Technology, Beijing, China

Xingzhong Xu

Roles Supervision, Validation

Affiliation School of Mathematics and Statistics, Beijing Institute of Technology, Beijing, China

Competing Interests

The authors have declared that no competing interests exist.