1. Department of Intelligent Mechanical Systems EngineeringKagawa UniversityTakamatsu 761‐0396Japan
2. JST‐PRESTSaitama 332‐0012Japan
3. CSIRO, Material Science and EngineeringClaytonVIC 3030Australia
4. Department of Mechanical EngineeringThe University of TokyoTokyo 113‐8656Japan