1. Department of Biomedical Engineering, Seoul National University College of Medicine, Seoul, Korea
2. Department of Rehabilitation Medicine, Seoul National University Boramae Medical Center, Seoul, Korea
3. Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, Korea
4. Department of Mechanical and System Design Engineering, Hongik University, Seoul, Korea
5. School of Architecture, Hongik University, Seoul, Korea
6. Hyundai Motors Namyang R&D Division, Hwaseong-si, Korea