1. Research Center of Healthcare & Welfare Instrument for the Aged, Division of Biomedical Engineering, College of Engineering, Jeonbuk National University, Jeonju, Korea.
2. Department of Electrical Engineering and Computer Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Korea.
3. College of Nursing, Research Institute of Nursing Science, Jeonbuk National University, Jeonju, Korea.