1. Ph.D. Candidate, Dept. of Architecture and Architectural Engineering, Seoul National Univ., Gwanak-ro 1, Gwanak-gu, Seoul 151-742, Korea.
2. Professor, Dept. of Architecture and Architectural Engineering, Seoul National Univ., Gwanak-ro 1, Gwanak-gu, Seoul 151-742, Korea.
3. Professor, Dept. of Architecture and Architectural Engineering, Seoul National Univ., Gwanak-ro 1, Gwanak-gu, Seoul 151-742, Korea (corresponding author).