1. Center for Healthcare Robotics, Korea Institute Science and Technology, Seoul, South Korea
2. Department of Electrical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea
3. School of Mechanical, Aerospace and Nuclear Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea
4. Department of Mechanical Engineering, Ulsan National Institute of Science and Technology, Ulsan, South Korea