1. Assistant Professor, Graduate School of Engineering, Osaka City Univ., 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan (corresponding author).
2. Kansai Research Center, Kokusai Kogyo Co. Ltd., 1-1-15 Nishinagasu-cho, Amagasaki, Hyogo 660-0805, Japan.
3. Professor, Graduate School of Engineering, Osaka City Univ., 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.