About the Authors

Ryoichi Nakashima

one.island.one@gmail.com

Affiliations Research Institute of Electrical Communication, Tohoku University, Sendai, Japan, Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Tokyo, Japan

Satoshi Shioiri

Affiliations Research Institute of Electrical Communication, Tohoku University, Sendai, Japan, Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Tokyo, Japan

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: RN SS. Performed the experiments: RN. Analyzed the data: RN. Wrote the paper: RN SS.