Coordinated rescheduling of precast production

Schedule disturbances are common and inevitable in the process of precast production. Not only is it necessary for the precaster to repair existing production schedule to accommodate these unexpected changes, it is also critical that the precaster and the contractor reach agreement on a new delivery schedule. This research has proposed and developed a coordinated production reactive scheduling model for this purpose. The fundamental basis of the model involves the formulation of the precast production rescheduling problem as a multiobjective optimization problem, in a way that includes objectives from both the precaster and the contractor. A multiobjective genetic algorithm is applied in the global search procedure for a rich set of alternative repaired schedules. As a further enhancement to the proposed model, a local search process is implemented to conduct incremental exploration of the search space in specific areas identified by either the precaster or the contractor. Together, the alternative schedules generated by the global search procedure as well as the specific schedules from the local search provide the precaster and the contractor useful insight into the trade-offs between their objectives as they negotiate a new delivery schedule.