1. Department of Intelligent Machines and System Engineering, Hirosaki University, 3 Bunkyo-cho, Hirosaki, 036-8561 Japan
2. Department of Aeronautics and Space Engineering, Graduate School of Engineering Tohoku University Aoba-yama 01, Sendai 980-8579, Japan
3. Department of Aeronautics and Space Engineering, Graduate School of Engineering, Tohoku University, Aoba-yama 01, Sendai 980-8579, Japan