1. Ph.D. Candidate, College of Management and Economics, Tianjin Univ., Tianjin 300072, China; Lecturer, School of Economics and Management, Tianjin Renai College, Tianjin 301636, China.
2. Marie Skłodowska–Curie Fellow, Dept. of Engineering, Univ. of Cambridge, Cambridge CB3 0FA, UK.
3. Professor, College of Management and Economics, Tianjin Univ., Tianjin 300072, China (corresponding author).
4. Ph.D. Candidate, College of Management and Economics, Tianjin Univ., Tianjin 300072, China.