About the Authors

Takahiro Kawabe


Affiliation Human and Information Science Laboratory, NTT Communication Science Laboratories, Atsugi, Kanagawa, Japan

Competing Interests

The author has read the journal's policy and has the following conflicts. TK is an employee of NTT Communication Science Laboratories, which is a basic-science research section of Nippon Telegraph and Telecommunication (NTT). There are no patents, products in development or marketed products to declare. This does not alter the author's adherence to all the PLoS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Author Contributions

Conceived and designed the experiments: TK. Performed the experiments: TK. Analyzed the data: TK. Contributed reagents/materials/analysis tools: TK. Wrote the paper: TK.