Funding for this research was provided by:
Japan Society for the Promotion of Science (15K14617, 26291098)
Received: 1 August 2017
Accepted: 10 October 2017
First Online: 17 October 2017
Ethics approval and consent to participate
: Our experiment received institutional ethics approval from the Ethics Committee of the Graduate School of Engineering at Chiba University (no. 26-23), and written informed consent was obtained from each participant.
: All participants gave written informed consent for publication after a complete explanation of this study.
: The authors declare that they have no competing interests.
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