1. Department of Nursing, Gifu College of Nursing, Hashima, Gifu, 501-6295, Japan
2. Department of Mathematical Sciences, Graduate School of Engineering, Osaka Prefecture University, Naka-ku, Sakai, Osaka, 599-8531, Japan
3. Department of Mathematical and Statistical Methods, Poznań University of Life Sciences, Wojska Polskiego 28, 60-637 Poznań, Poland