1. Department of Mechanical and Control Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8552, Japan; inoueh@mep.titech.ac.jp
2. Department of Mechanical Engineering, UMIST, PO Box 88, Manchester M60 1QD, United Kingdom; john.j.harrigan@umist.ac.uk, steve.reid@umist.ac.uk