1. Research Fellow, Samsung Economic Research Institute, Seoul 06620, South Korea.
2. Assistant Professor, Dept. of Industrial and Management Engineering, Sunmoon Univ., Korea.
3. Professor, School of Civil and Environmental Engineering, Yonsei Univ., Seoul, Korea (corresponding author).
4. Associate Professor, Dept. of Decision Sciences, George Washington Univ., Washington, DC.
5. Senior Lecturer, Research School of Management, Australian National Univ., Canberra, Australia.