對於提昇倉儲管理的效率而言，揀貨作業是最重要的關鍵因素。過去對於揀貨作業的研究，大多考量單一揀貨人員或是多個揀貨人員的行走距離與時間。對於實際的倉儲系統而言，揀貨作業不但包含揀貨時間以及因阻塞而造成揀貨箱在等待處理的等待時間，如果僅考慮揀貨人員之行走距離或時間並無法精確評估揀貨作業的績效，必須加入揀貨時間與揀貨箱的等待時間，才能有效反映整體的作業效率。本研究視揀貨模式為一個等候網路，並考慮在零散式揀貨系統下的單一揀貨人員的行走時間，揀貨時間與揀貨箱等待處理的時間，其平均加總為此揀貨模式的訂單週期循環時間。本研究利用eM-plant模擬軟體模擬此倉儲模式，並針對三種儲位指派進行模擬測試，以用來比較所提出的分析方法績效，而結果顯示絕對差異皆小於2%。

Order picking is one of the most important key factors for an efficient warehouse management. Most of previous research in order picking considered only travel distance and time of single-picker or multiple-pickers. However, for a real warehouse system, order picking includes picking time as well as waiting time because of the congestion to cause the container has to wait be processed. For this reason, consider only about the travel distance or travel time of the picker, it may not evaluation of the efficiency for the picking operations. It must join together with picking time and waiting time for the container.
　　The purpose of this research is to study the single-picker’s travel time, picking time and the effect of congestion on the order picking operations in a pick-and-pass system where the picking follows the walk-and-pick method of order retrieval with sequential one-way travel. The picking model can be treated as an open Queueing Network and this research can compute an order mean cycle time. A simulation model is proposed and developed to implement this analytically method using eM-plant software to test three storage assignment types. The results show that the absolutely differences between the analytically model and the simulation results were below 2 %.

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