1. Mitsubishi Electric Corporation, Information Technology R&D Center, 5-1-1 Ofuna, Kamakura, Kanagawa 247-8501, Japan
2. Mitsubishi Electric Corporation, High Frequency and Optical Device Works, 4-1 Mizuhara, Itami, Hyogo 664-8641, Japan
3. Mitsubishi Electric Corporation, Kamakura Works, 325 Kamimachiya, Kamakura, Kanagawa 247-8520, Japan