Exact and heuristic methods for placing ships in locks
In: European Journal of Operational Research. Elsevier: Amsterdam. ISSN 0377-2217; e-ISSN 1872-6860, meer
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| Trefwoord |
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| Author keywords |
Ship placement problem; Packing; Heuristics; Lock scheduling;Decomposition |
| Auteurs | | Top |
- Verstichel, J., meer
- De Causmaecker, P., meer
- Spieksma, F., meer
- Vanden Berghe, G., meer
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| Abstract |
The ship placement problem constitutes a daily challenge for planners in tide river harbours. In essence, it entails positioning a set of ships into as few lock chambers as possible while satisfying a number of general and specific placement constraints. These constraints make the ship placement problem different from traditional 2D bin packing. A mathematical formulation for the problem is presented. In addition, a decomposition model is developed which allows for computing optimal solutions in a reasonable time. A multi-order best fit heuristic for the ship placement problem is introduced, and its performance is compared with that of the left-right-left-back heuristic. Experiments on simulated and real-life instances show that the multi-order best fit heuristic beats the other heuristics 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. |
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