1. School of Management and Economics Beijing Institute of Technology Beijing 100081 China
2. Department of Industrial Engineering and Operations Research University of California Berkeley California 94720 USA
3. Krannert School of Management Purdue University West Lafayette Indiana 47907 USA
4. College of Engineering University of California Berkeley California 94720 USA
5. Faculty of Engineering and Faculty of Business and Economics The University of Hong Kong Hong Kong 999077 China