Operator-scheduling using a constraint satisfaction technique in port container terminals

In port container terminals, the efficient scheduling of operators of handling equipment such as container cranes, yard cranes, and yard trucks is important. Because of many complicated constraints, finding a feasible solution, as opposed to the optimal solution, within a reasonable amount of computing time can be considered satisfactory from a practical point of view. The major constraints include the following: restrictions on the minimum workforce assignment to each time slot, the maximum total operating time per operator per shift, the minimum and maximum consecutive operating times for an operator, types of equipment that can be assigned to each operator, and the available time slots for each operator or piece of equipment. The operator-scheduling problem is defined as a constraint-satisfaction problem, and its solution is obtained by utilizing a commercial software. An actual problem, collected from a container terminal in Pusan, Korea, is solved through the solution procedure proposed in this study.