1. Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan (Corresponding author), e-mail: kawabata@fract.t.u-tokyo.ac.jp, https://orcid.org/0000-0003-2767-1579
2. Department of Systems Innovation, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
3. National Maritime Research Institute, Shinkawa 6-38-1, Mitaka 181-0004, Japan
4. Joining & Welding Research Institute, Osaka University, Miho-ga-oka, 11, Suita 567-0047, Japan