1. Department of Industrial and Manufacturing Engineering, Pennsylvania State University, University Park, PA 16802 e-mail:
2. The G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 e-mail:
3. School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 e-mail:
4. Department of Mechanical Engineering, University of Bath, Bath BA2 7AY, UK e-mail: