1. Assistant Professor, Dept. of Construction Management and Engineering, Univ. of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands (corresponding author).
2. Associate Professor, Dept. of Building, National Univ. of Singapore, 4 Architecture Dr., Singapore 117566, Singapore.
3. Mapletree Investments Pte Ltd., 1 Maritime Square, 13-01 HarbourFront Centre, Singapore 099253, Singapore.