1. Ph.D. Student, Dept. of Architecture and Architectural Engineering, Seoul National Univ., Kwanak-ro 1, Kwanak-gu, Seoul 151-742, Korea.
2. Professor, Dept. of Architecture and Architectural Engineering, Seoul National Univ., Kwanak-ro 1, Kwanak-gu, Seoul 151-742, Korea (corresponding author).
3. Professor, Dept. of Architecture and Architectural Engineering, Seoul National Univ., Kwanak-ro 1, Kwanak-gu, Seoul 151-742, Korea.
4. M.S. Student, Dept. of Architecture and Architectural Engineering, Seoul National Univ., Kwanak-ro 1, Kwanak-gu, Seoul 151-742, Korea.