“…Let q ϭ [7,8,10,3,7,8,7] be the customer demand rates in items/hour, h ϭ [9,7,2,9,7,6,4] in $/(item-hour) and ϭ 60 items/hour. To solve ISP either the dynamic programming model (Petersen and Rao 1993) or the nonlinear programming model in PROPS ϩ (Petersen and Taylor 1994), can be used. The optimal solution is AON and assigns customers 1, 2, 4, and 5 to the highest priority class 1; customers 6 and 7 to class 2; and customer 3 to the lowest priority class 3. x 1 ϭ 25, x 2 ϭ 15 and x 3 ϭ 10.…”