1. IST Co. Inc., Jeonju, Korea
2. Biomedical Research Institute, Jeonbuk National University Hospital, Jeonju, Korea
3. Division of Biomedical Engineering, Jeonbuk National University, Jeonju, Jeonbuk, Korea
4. Research Center of Healthcare & Welfare Instrument for the Aged, Jeonbuk National University, Jeonju, Jeonbuk, Korea