1. Highway Research Institute, Korea Institute of Civil Engineering and Building Technology, 283 Goyangdae-Ro, Ilsanseao-Gu, Goyang-Si 411-712, South Korea.
2. Global Cooperation Division, Korea Institute of Civil Engineering and Building Technology, 283 Goyangdae-Ro, Ilsanseao-Gu, Goyang-Si 411-712, South Korea.
3. Department of Computer Science and Information, Myongji College, 134 Gajwa-Ro, Seodaemun-Gu, Seoul, 120-776, South Korea.