1. Division of Mechanical and Automotive Engineering, College of Engineering; Wonkwang University, 460 Iksandae-ro; Iksan Jeonbuk 570-749 Republic of Korea
2. Department of Orthopedic surgery, Daejeon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 64, Daeheungro, Jung-gu, Daejeon, 301-723, Republic of korea