Hybrid Algorithm to Minimize Total Weighted Wait-Time of Ships for Navigation Co-Scheduling in the Three Gorges Project

There are two dams in the famous Three Gorges Project on the Yangtze River, i.e., the upriver Three Gorges Dam with two locks and the downriver Gezhouba Dam with three locks. They have become traffic bottlenecks of the Yangtze River. The navigation co-scheduling of the two dams involves operation timetable of the five locks and the passage scheme of the ships. It is a very complex combinatorial optimization problem. The optimization objectives considered here is the total weighed wait-time of all ships within the scheduling period. A Mixed-Integer Nonlinear Programming (MINLP) model is established to represent this problem and a hybrid algorithm of simulated annealing and local search is designed to obtain the near optimal scheduling. The performance of this algorithm is tested under real historical data of real NCS system. And the result shows that the approach is feasible.