| Abstract: | To build a scheduling system for shipbuilding, we have adopted a hierarchical architecture and developed a constraint directed graph search technique for erection scheduling at the dock. First, in the hierarchical architecture, detailed schedules for the lower-level assembly plants are delegated to the individual plant's schedulers as long as the requirements from the higher-level scheduler are satisfied. However, if lower-level scheduling is impossible, the higher-level scheduler attempts to adjust the original requirements. Second, in the constraint directed graph search, the concepts of graph expansion and constraint directed pruning are amalgamated into an algorithm. The approaches are implemented in the DAS-ERECT system which is a sub-system of the DAS project undertaken for the Daewoo Shipbuilding Company. |
