1. Department of Healthcare Engineering, Chonbuk National University, Jeonju, South Korea
2. College of Medicine, Chungbuk National University, Cheongju, South Korea
3. School of Electronics and Computer Engineering, Chonnam National University, Gwangju, South Korea
4. Division of Biomedical Engineering, Chonbuk National University, Jeonju, South Korea
5. Research Center of Healthcare & Welfare Instrument for the Aged, Chonbuk National University, Jeonju, South Korea