1. School of Regional Innovation and Social Design Engineering Faculty of Engineering, Kitami Institute of Technology, 165 Koen‐cho Kitami Hokkaido 090‐8507 Japan
2. Institute for Protein Research Osaka University, 3‐2 Yamadaoka Suita Osaka 565‐0871 Japan
3. Graduate School of Science Osaka University, 1‐1 Machikaneyamacho Toyonaka Osaka 560‐0043 Japan
4. Graduate School of Information Sciences Hiroshima City University, 3‐4‐1 Ozuka‐Higashi Asa‐Minami‐Ku Hiroshima 731‐3194 Japan