About the Authors
- Shifeng Han
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Roles Investigation, Methodology, Writing – original draft, Writing – review & editing
* E-mail: 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.