Puzzle-based storage (PBS) systems provide a space efficient solution for storage and retrieval of unit loads (e.g., cars, boxes) in the very land-expensive urban environment. In this work, we formulate a highly generic optimal retrieval problem, consisting of any number of loads to be retrieved, and an arbitrary number of I/O points and empty locations (escorts) on a two-dimensional lattice graph. We theoretically analyze the characteristics of the problem and propose a set of graph search algorithms to tackle the inherent complexities thereof. In contrast to existing work in the field, we investigate the runtime-memory tradeoff pertaining to our problem, highlighting the possible benefits and limitations of our heuristic search and tabulation techniques. Our results demonstrate that our algorithms are capable of optimally solving moderate-sized PBS problems using a limited amount of memory and in a reasonable amount of time.

中文翻译：

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启发式搜索和制表的基于拼图的存储中的最佳检索

基于拼图的存储 (PBS) 系统为在土地非常昂贵的城市环境中存储和检索单位负载（例如汽车、箱子）提供了一种空间有效的解决方案。在这项工作中，我们制定了一个高度通用的最优检索问题，包括要检索的任意数量的负载，以及二维点阵图上的任意数量的 I/O 点和空位置（护送）。我们从理论上分析了问题的特征，并提出了一套图搜索算法来解决其固有的复杂性。与该领域的现有工作相比，我们调查了与我们的问题有关的运行时内存权衡，强调了我们的启发式搜索和制表技术的可能优势和局限性。