Professor John Billingsley National Centre for Engineering in Agriculture (NCEA), Faculty of Engineering & Surveying Mechanical & Mechatronic Engineering, University of Southern Queensland, Toowoomba Qld 4350 Australia Phone: + 61 7 4631 2513Email: billings@usq.edu.au

Denny Oetomo Department of Mechanical Engineering The University of Melbourne VIC 3010 Australia Tel: +61 3 8344 6795 Fax: +61 3 9347 8784 Email: doetomo@unimelb.edu.au