The 2012 International Conference on Logistics and Maritime Systems location:Bremen, Germany date:22-24 August 2012
The placement of in and outbound ships in locks constitutes a daily challenge for planners in tide river harbors. In essence, this entails positioning a set of ships into as few lock chambers as possible while satisfying a number of general and specific placement constraints. These specific constraints make the ship placement problem different from traditional 2D bin packing. A mathematical formulation for the problem is presented. This formulation describes the ship placement problem of both inland locks and locks in ports, under a wide range of real-life constraints. In addition, a decomposition model is developed, which allows for computing optimal solutions in a reasonable time. A three-way best fit heuristic for the ship placement problem is introduced, and its performance is compared with that of the existing left-right-left-back heuristic. Experiments on simulated real-life instances show that the three-way best fit heuristic beats the existing solution method by a landslide, while maintaining comparable calculation times. Finally, the new heuristic's optimality gap is small, while it clearly outperforms the exact approach with respect to calculation time.