1. JST, PRESTO, Saitama, Japan.
2. Department of Mechano-Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo, Japan.
3. Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom.
4. Department of Engineering and Information Technology, Bern University of Applied Sciences, Biel, Switzerland.
5. Department of Informatics, University of Zurich, Zurich, Switzerland.