1. Department of Anesthesiology, Graduate School of Medicine, Chiba University, Chiba, Japan
2. Department of Anesthesiology, Chiba University Hospital, Chiba, Japan
3. Functional Technology Department, Section 4, R&D Division Electronic Device and Component, Manufacturing Headquarters and Engineering Headquarters, MinebeaMitsumi, Fukuroi, Japan
4. Sensing Device Business Unit, Electronic Device Division, Electronic Device and Component Manufacturing Headquarters, MinebeaMitsumi, Fujisawa, Japan
5. Sales Planning Office, Bed Sensor Product Management Division, MinebeaMitsumi, Tokyo, Japan
6. Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan