D.-U. Park1, S.-J. Chang1, Y.-S. Jeong1
1: Seismic research and test center, Yangsan, South Korea
H. Park1, G. Chung1, S. Chang1
1: CENITS Corporation Inc., Seoul, South Korea
M. Ju1, S. Jeon1, K. Park1
1: Yonsei University, Seoul, South Korea