1. Graduate School of Natural Science and Technology, Department of Medical Bioengineering, Okayama University 3-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
2. Graduate School of Interdisciplinary Science and Engineering in Health Systems, Department of Medical Bioengineering, Okayama University 3-1-1, Tsushima-naka, Kita-ku, Okayama 700-8530, Japan