1. Division of Electrical
Engineering and Computer Science, Kanazawa University, Kanazawa 920-1192, Japan
2. COMP Centre of Excellence,
Department of Applied Physics, Aalto University, Helsinki FI-00076, Finland
3. Department of Earth and Planetary Materials
Science, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578, Japan
4. ACT-C, Japan Science
and Technology Agency, Saitama 332-0012, Japan