1. Coastal Development & Ocean Energy Research Division, Korea Institute of Ocean Science & Technology (KIOST), 787 Haean-ro, Ansan 426-744, South Korea
2. Department of Mechanical Engineering, Sungkyunkwan University, 2066 Seobu-Ro, Suwon 440-746, South Korea
3. Department of Mechanical Engineering and Mechanics, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, USA