A GA and Time Window Based Rolling Method for Dynamic Berth Allocation Problems

The berth allocation problem can be regarded as an optimization problem that schedules the docking time and location for cargo ships to minimize the waiting time and loading/unloading time. The berth allocations problem can be classified into continuous and discrete problems depending on the type of berths is either long public berth or is short and dedicated. This research focuses on the former ones. Previous researches usually assume the arrival information of ships are fixed, which is not practical in the real applications. The on time rate of ship arrivals is not high and the problem have uncertainties involved. This research proposes a time window and GA based rolling scheduling method for real berth allocations to deal with the uncertainties. The scheduling task is triggered concurrently by an arrived ship. Starting from the trigger time, a specified time window is constructed to round in the ships that have been docked and that are anticipated to arrive within the time window, for scheduling consideration. Then, a GA optimization model for theses ships is built to schedule the docking times and positions for these ships. The arrived ship is then assigned with the docking time and location. A prototype system is developed to verify the proposed method and a simulation framework is built to simulate the arrivals of ships. Sixteen numerical examples of four types of arrival patterns are constructed to test the performance of the method. Scheduling results of the method are compared with those from the FCFS method. Results show that the method outperforms FCFC methods in most of the examples and is more practical than other methods.