1. Graduate School of Natural Science and Technology, Okayama University, Tsushimanaka, Okayama 700-8530
2. Dept. Electrical & Electronic Eng., Muroran Institute of Technology, Mizumoto, Muroran, Hokkaido 050-8585
3. Faculty of Maritime Sciences, Kobe University, Higashi-Nada, Kobe 658-0072
4. Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198
5. Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043