About the Authors

Shin Watanabe

Affiliation Department of Electrical Engineering and Bioscience, Waseda University, Shinjuku-ku, Tokyo, Japan

Atsuko Takamatsu

atsuko_ta@waseda.jp

Affiliation Department of Electrical Engineering and Bioscience, Waseda University, Shinjuku-ku, Tokyo, Japan

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: AT SW. Performed the experiments: SW. Analyzed the data: SW. Wrote the paper: SW AT.