Multi-Objective Algorithm for Navigation Co-Scheduling of the Three Gorges Dam and Gezhouba Dam

In order to improve the navigation capability of the ship locks in the traffic management and optimize the ship scheduling, at the engineering background of navigation co-scheduling of the Three Gorges Dam and Gezhouba Dam, a mathematic model is introduced with the scheduling principle of navigation constraints and first-come-first-served priority, and the objectives of maximizing the whole navigation capability, minimizing the total ships waiting time and the cost of used water, balancing the navigation capacity of the Three Gorges Dam and Gezhouba Dam. The co-scheduling takes comprehensive account of the two five-step ship locks of the Three Gorges Dam and three one-step ship locks of the Gezhouba Dam. As far as the structure of the model is concerned, the key of the model is focused on the global optimization of the whole navigation capacity of the two dams, and the local optimization for single ship lock should be taken into account. The output of the model is the scheduling plan, including the time sequence to open the lock gates and the set place information of the ships in each ship lock during the certain period of one plan. The scheduling plan is attributed to the scheduling problem of the time table from time aspect, coupled with bin packing problem from space aspect, so it is an NP-hard combinatorial optimization problem. To deal with this kind of navigation co-scheduling model, a novel constrained multi-objective heuristic algorithm (CMOHA) is accordingly designed. Through numerical experiment's analysis, illustrative results show that the navigation co-scheduling model is feasible, safe and efficient scheme for ship scheduling can be obtained, and the whole passing ability of the navigation establishment can be remarkably improved.