The container retrieval problem (CRP) is a very important issue for container terminals. The CRP seeks to find an optimal sequence of operations for the crane to retrieve all the containers from the bay according to a predefined order. An optimal sequence of operations is obtained by either reducing the number of container relocations or reducing any kind of working cost performed by the crane, i.e., energy, time, etc. Although the former is the main objective function discussed in the literature, minimizing the number of relocations does not ensure the solution with the minimal working cost, as evidenced in this paper. Therefore, in this study, a crane’s trajectory is defined to better measure the crane’s working cost, and the optimization goal is to minimize the crane’s working time considering the crane’s trajectory. Moreover, it proposes exact methods and a reactive GRASP algorithm for the CRP. The experimental results show that the proposed algorithm is able to provide better solutions for both the number of container relocations and the crane’s working time, when compared to heuristic approaches in the recent literature.

中文翻译：

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反应式GRASP元启发式方法可解决集装箱取回问题，从而减少起重机的工作时间

集装箱检索问题（CRP）对于集装箱码头来说是一个非常重要的问题。CRP试图为起重机找到最佳操作顺序，以根据预定顺序从托架中取出所有集装箱。通过减少集装箱搬迁次数或减少起重机的任何工作成本（例如，能源，时间等），可以获得最佳的操作顺序。尽管前者是文献中讨论的主要目标函数，但应尽量减少如本文所证明的，重新安置的数量不能确保以最低的工作成本解决方案。因此，在本研究中，定义了起重机的轨迹以更好地衡量起重机的工作成本，并且优化目标是考虑到起重机的轨迹来使起重机的工作时间最小化。此外，它为CRP提出了精确的方法和反应性GRASP算法。实验结果表明，与最新文献中的启发式方法相比，该算法能够为集装箱重定位次数和起重机的工作时间提供更好的解决方案。