1. Durham University,Department of Engineering,Durham,UK,DH1 3LE
2. Oita University,Division of Mechatronics,Oita,Japan,870-1192
3. Wuhan University,School of Electrical Engineering and Automation,Wuhan,P. R. China,430072
4. Saga University,Department of Electrical and Electronic Engineering,Saga,Japan,840-0027