Note. Optimal Storage Assignment Policies for Automated Storage and Retrieval Systems with Stochastic Demands
Note. Optimal Storage Assignment Policies for Automated Storage and Retrieval Systems with Stochastic Demands
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DOI：
10.1287/mnsc.44.1.142
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发表时间：
1998
影响因子：
5.4
通讯作者：
U. W. Thonemann;M. Brandeau
中科院分区：
文献类型：
--
作者：
U. W. Thonemann;M. Brandeau
在现有的AS/RS研究中，存储分配策略是基于项目类型j将被存储（并随后被检索）的概率进行评估的。本文将Hausman et al.（1976）的基于周转率和基于类别的分配策略应用于随机环境，通过识别物品类型j的第k个托盘：经常需要的托盘存储在靠近输入/输出点的位置，很少需要的托盘存储在存储机架的末端。我们考虑离散存储机架和连续存储机架。对于连续机架的情况下，我们开发了一个表达式的预期单程旅行时间均匀和指数分布的需求。我们发现，基于周转的政策应用于随机环境是最佳的（它最大限度地减少了单程旅行时间），并在随机环境中应用的基于周转和基于类的分配政策减少了预期的存储/检索时间相比，随机分配。这些节省可以直接转化为现有系统吞吐量的增加，并可用于改进拟议系统的设计。
In existing AS/RS research, storage assignment policies are evaluated based on the probability that item type j will be stored (and subsequently retrieved). This note applies the turnover-based and class-based assignment policies of Hausman et al. (1976) to a stochastic environment by identifying the kth pallet of item type j: Frequently demanded pallets are stored close to the input/output point and rarely demanded pallets are stored at the end of the storage rack. We consider a discrete storage rack and a continuous storage rack. For the continuous rack case, we develop an expression for expected one-way travel time given uniform and exponentially distributed demand. We show that the turnover-based policy applied to the stochastic environment is optimal (it minimizes one-way travel time) and that both the turnover-based and class-based assignment policies applied in the stochastic environment reduce expected storage/retrieval time compared with random assignment. These savings can be directly translated into increased throughput capacity for existing systems and can be used to improve the design of proposed systems.