1. a Department of Mechanical Engineering (M/C 251) , University of Illinois , Box 4348, Chicago, IL, 60680, USA
2. b Operations and Decision Systems , Laval University , Ste Foy, Quebec, Canada
3. c School of Industrial Engineering, Purdue University , W. Lafayette, IN, 47907, USA
4. d School of Electrical Engineering, Purdue University , W. Lafayette, IN, 47907, USA