A decision-tree stacking heuristic minimising the expected number of reshuffles at a container terminal
Reshuffling containers, one of the daily operations at a container terminal, is time consuming and increases a ships berthing time. We propose a decision-tree heuristic to minimise the expected number of reshuffles when arriving containers should be stacked in a block of containers with an arbitrary number of piles. The heuristic algorithm uses the optimal solutions of a stochastic dynamic programming model. Since the total number of states of the dynamic programming model increases exponentially, the model can only solve small-scale problems in a reasonable time. To solve large-scale problems, the heuristic uses the results of the exact model for small-scale problems to generate generalised decision trees. These trees can be used to solve problems with a realistic number of piles. The numerical experiments show the effectiveness of the algorithm. For small-scale problems, the trees can quickly make optimal decisions. For large-scale problems, the decision-tree heuristic significantly outperforms stacking policies commonly used in practice. Using the decision trees, we can compare the performance of a shared-stacking policy, which allows containers of multiple ships to be stacked on top of each other, with a dedicated-stacking policy. Shared-stacking appears to outperform dedicated-stacking.
|Keywords||container reshuffling, container terminal, decision tree, heuristic algorithm, shared-stacking policy|
|Persistent URL||dx.doi.org/10.1080/00207543.2013.861618, hdl.handle.net/1765/76740|
|Series||ERIM Top-Core Articles|
|Journal||International Journal of Production Research|
Gharehgozli, A.H, Yu, Y, de Koster, M.B.M, & Udding, J.T. (2014). A decision-tree stacking heuristic minimising the expected number of reshuffles at a container terminal. International Journal of Production Research, 52(9), 2592–2611. doi:10.1080/00207543.2013.861618