1. a University of Michigan, Industrial and Operations Engineering , 2797 IOE Building, 1205 Beal Avenue, Ann Arbor, 48109 United States
2. b NSF Engineering Research Center for Reconfigurable Manufacturing Systems, University of Michigan , 2350 Hayward St., Ann Arbor, MI 48109, USA
3. c Department of Management Science and Engineering , 380 Panama Way, Stanford, CA 94305, USA