1. Dept. of Mechanical Engineering City University of Hong Kong Hong Kong 999077 China
2. Dept. of Electrical and Computer Engineering Michigan State University MI 48840 USA
3. The Int. Research Centre for Nano Handling and Manufacturing of China Changchun University of Science and Technology Changchun 130022 China
4. Dept. of Biomedical Engineering City University of Hong Kong Hong Kong 999077 China
5. James Watt School of Engineering University of Glasgow Scotland G12 8QQ UK
6. Sch. of Mechatronic Engineering and Automation Shanghai University Shanghai 200444 China
7. Dept. of Computer Science City University of Hong Kong Hong Kong 999077 China