1 School of Engineering and Information Technology, University of New South Wales, Canberra, ACT 2600, Australia.
2 School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK.
3 Department of Mathematical Sciences, Indiana University-Purdue University Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202, USA.
4 Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260.
5 Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea.