1. Department of Applied Science for Electronics and Materials; Kyushu University; Kasuga Fukuoka 816-8580 Japan
2. Department of Control and Information Systems Engineering; Kurume National College of Technology; Kurume Fukuoka 830-8555 Japan
3. Faculty of Engineering; Kyushu Institute of Technology; Kitakyushu Fukuoka 804-8550 Japan
4. Department of Electrical Engineering; Fukuoka Institute of Technology; Fukuoka 811-0295 Japan