1. Grado Department of Industrial & Systems, Engineering, Virginia Tech; 217 Durham Hall, 1145 Perry St Blacksburg VA 24060 (USA)
2. Dept of Industrial Engineering; University of Naples Federico II (Italy), School of Systems and enterprises, Stevens, Institute of Technology (USA); Piazzale Tecchio 80 80125 Napoli (Italy)
3. Dept of Industrial Engineering; University of Naples Federico II (Italy); Piazzale Tecchio 80 80125 Napoli (Italy)