1. Assistant Professor, Dept. of Construction Management and Engineering, Univ. of Twente, P.O. Box 217, AE Enschede 7500, The Netherlands. E-mail: t.hartmann@ctw.utwente.nl
2. Ph.D. Student, Center for Integrated Facility Engineering, Stanford Univ., Terman Engineering Center, Stanford, CA 94305. E-mail: gaoju@stanford.edu
3. Professor, Center for Integrated Facility Engineering, Stanford Univ., Terman Engineering Center, Stanford, CA. E-mail: fischer@stanford.edu