1. Assistant Professor, School of Construction Engineering, Kyungil Univ., Gyeongbuk 712-701, Korea.
2. Assistant Professor, Economics of the Sustainable Built Environment (ESBE) Lab, School of Building Construction, Georgia Institute of Technology, Atlanta, GA 30332-0680 (corresponding author).
3. Professor, Dept. of Civil and Environmental Engineering, Yonsei Univ., Seoul 120-749, Korea.