1. Ph.D. Student, Dept. of Construction Management, Tsinghua Univ., Beijing 100084, China.
2. Research Assistant, Dept. of Construction Management, Tsinghua Univ., Beijing 100084, China.
3. Associate Professor, Dept. of Construction Management, Tsinghua Univ., Beijing 100084, China (corresponding author).
4. Dept. of Construction Management, Tsinghua Univ., Beijing 100084, China.