1. Department of Industrial Engineering and Operations Research, University of California, Berkeley, Berkeley, California 94720
2. Department of Industrial Engineering and Operations Research, University of California, Berkeley, Berkeley, California 94720; and Department of Civil and Environmental Engineering, and Tsinghua-Berkeley Shenzhen Institute, University of California, Berkeley, Berkeley, California 94720
3. Anderson School of Management, University of California, Los Angeles, Los Angeles, California 90095