Problem Statement

    As e-commerce companies such as Amazon become the dominant way people
buy goods, increasing strain has been put on getting an order to a customer as quickly, reliably, and efficiently as possible [2]. A critical part of this supply chain is the logistics of the warehouse that these online companies use to store products until they are purchased, picked, and shipped. In-arguably, the most important function in a warehouse is the picking process, which accounts for 55% of operational expenses [1]. Since under-performance in picking can lead to bad overall effectiveness and high operational costs, it is imperative that a company’s warehouse is organized in such a way that it allows for the most effective order picking possible [3].
    There are two basic implementations of order picking, zone and discrete order picking.
    While discrete order picking has many advantages, mainly reliability and simplicity, zone picking is definitely the better organizational scheme in a warehouse due to significantly decreased travel times on smaller orders [3]. Simply put, zone picking offers faster pick times than discrete order picking, with the same reliability.
    The most important thing to consider in order picking is the distance a picker walks during each order, as this directly correlates with the amount of worker hours a company must pay for [1],[ 3]. It is possible to cut the distance walked by configuring the layout of a warehouse, and by improving the organization of the warehouse. Configuring the layout of the facility is achieved by modifying the positions of the various conveyors, depots, and shelves. Carefully sorting the items and picker distribution based on item demand can help substantially increase the organization of the warehouse [3].