1. National Institute for Fusion Science, 322 Oroshi-cho, Toki-city, Gifu 509-5292, Japan
2. Fellow of the Japan Society for the Promotion of Science (JSPS)
3. FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM- FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein, The Netherlands
4. Dept. of Mechanical Engineering, Eindhoven University of Technology, Control Systems Technology group, PO Box 513, 5600 MB Eindhoven, The Netherlands
5. Department of Mechanical Engineering, Dynamics and Control Group, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
6. Department of Applied Mathematics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
7. Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan