1. Fukuoka University,Department of Electrical Engineering,Fukuoka,Japan
2. Grad. Sch. Sci. Tech, Kumamoto Univ.,Dept. of Comput. Sci. & Electr. Eng.,Kumamoto,Japan
3. Kumamoto University,Technical Division,Kumamoto,Japan
4. Institute of Industrial Nanomaterials, Kumamoto University,Kumamoto,Japan