[1] Smith Coll, Picker Engn Program, Northampton, MA 01063 USA
[2] Marquette Univ, Dept Biomed Engn, Milwaukee, WI 53201 USA
[3] Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA
[4] Iowa State Univ, Dept Ind & Mfg Syst Engn, Ames, IA 50011 USA