1. Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku,
Nagoya 464-8601, Japan
2. ESICB, Kyoto University, Kyodai Katsura, Nishikyo-ku, Kyoto 615-8520, Japan
3. Core Research for Evolutional Science and
Technology, Japan Science and Technology Agency, Honmachi, Kawaguchi 332-0012, Japan