1. Research Specialist, Construction Management and Economy Research Division, Construction System Innovation Research Dept., Korea Institute of Construction Technology, Goyang-Si, Gyeonggi-Do 411-712, Republic of Korea.
2. Ph.D. Candidate, Division of Construction Engineering and Management, School of Civil Engineering, Purdue Univ., West Lafayette, IN 47906-2051 (corresponding author).
3. Professor and Head, Division of Construction Engineering and Management, Purdue Univ., West Lafayette, IN 47906-2051.