1. i‐Powered Energy System Research Center (i‐PERC) The University of Electro‐Communications 1‐5‐1 Chofugaoka Chofu Tokyo 182‐8585 Japan
2. Faculty of Informatics and Engineering The University of Electro‐Communications 1‐5‐1 Chofugaoka chofu Tokyo 182‐8585 Japan
3. Department of Polymer Chemistry and Technology Kaunas University of Technology Radvilenu Plentas 19 Kaunas LT50254 Lithuania
4. Research Center for Advanced Science and Technology The University of Tokyo 4‐6‐1 Komaba, Meguro‐ku Tokyo 153‐8904 Japan