1. a College of Administrative Science , The University of Alabama in Huntsville , Huntsville , Alabama 35899 , USA
2. b Department of Applied Statistics, Operations Research and Quality , Universidad Politécnica de Valencia , Valencia , Spain
3. c Department of Industrial Engineering , Arizona State University , Tempe , Arizona 85207 , USA
4. d Department of Industrial Engineering , University of Arkansas , Fayetteville , Arkansas 72701 , USA