In the past thirty years the full turnover-based storage policy as described by Hausman et al. (1976, Management Science 22(6)) has been widely claimed to outperform the commonly used ABC class-based storage policy, in terms of the resulting average storage and retrieval machine travel time. In...

In this paper, we discuss an approximation method based on G/G/m queuing network modeling using Whitt’s (1983) queuing network analyzer to analyze pick-and-pass order picking systems. The objective of this approximation method is to provide an instrument for obtaining rapid performance...

In the warehouse of Ankor, a wholesaler of tools and garden equipment, various problems concerning the storage and retrieval of products arise. For example, heavy products have to be retrieved prior to light products to prevent damage. Furthermore, the layout of the warehouse differs from the...

A warehouse needs to have sufficient open locations to be able to store incoming shipments of various sizes. In combination with ongoing load retrievals open locations gradually spread over the storage area. Unfavorable positions of open locations negatively impact the average load retrieval...

The order batching problem (OBP) is the problem of determining the number of orders to be picked together in one picking tour. Although various objectives may arise in practice, minimizing the average throughput time of a random order is a common concern. In this paper, we consider the OBP for a...

In this study we consider a pick-to-pack orderpicking system, in which batches of orders are picked simultaneously from different(work) zones by a group of order pickers. After picking, the orders are transported by a conveyor to the next station for packing. Our aim is to determine the optimal...

This work aims at investigating the influence of picking batch size to average time in system of orders in a one-aisle warehouse under the assumption that order arrivals follow a Poisson process and items are uniformly distributed over the aisle's length. We model this problem as an M/G[k]/1...

Theory-testing with cases is ascertaining whether the empirical evidence in a case or in a sample of cases either supports or does not support the theory. There are two methodologies for theory-testing with cases, (a) testing in a single case (‘theory-testing single case study’), and (b)...

Pattern matching is comparing two patterns in order to determine whether they match (i.e., that they are the same) or do not match (i.e., that they differ). Pattern matching is the core procedure of theory-testing with cases. Testing consists of matching an “observed pattern” (a pattern of...

Theory-building with cases is (a) formulating new propositions that emerge from the empirical evidence in a sample of cases and (b) testing them in the same sample. The main difference with most other forms of generating new propositions (such as analyzing the theoretical literature,...