1. Department of Electronics and Control Engineering; National Institute of Technology, Niihama College 7-1 Yagumo-cho Niihama; Ehime 792-8580 Japan
2. Electronics and Information Engineering; Graduate School of Science and Engineering, Ehime University 3 Bunkyo-cho, Matuyama Ehime 790-8577; Japan
3. School of Environment, Science & Engineering; Southern Cross University, P.O. Box 157 Lismore; New South Wales 2480 Australia