Discrete Event Simulation Project Proposal

Class: DSES - 6620 Simulation Modeling And AnalysisName: Kevin LewellingDate: February 17, 2002To: Professor Ernesto Butierrez-Miravete

Background:Over the past year, the Super Stop & Shop store on the corner of Skiff St. and Dixwell Ave. in Hamden, CT has installed two new self-service systems. The first system was installed in the deli department and allows shoppers to place orders using an interactive touch screen computer system. The second self-service system allows shoppers to self-serve themselves through the checkout process.

Two systems have been implemented for the self-service checkout system. The earliest system targetted shoppers with 20 items or less. This system was configured with four checkout stations with a single customer service associate located in a central location as shown in Figure 1.

Following what appeared to be a successful trial period, Stop & Shop imstalled a new self-service checkout system, shown in Figure 2, which was re-oriented to the traditional isle type configuration. The new system not only has two isles designated for shoppers with 12 items or less but also has three new isles that can accommodate as many groceries as you care to scan. For the new system, S&S has hired two customer service associates that circulate between the checkout isles to aid shoppers in their checkout process. None of the checkout systems have employees dedicated to bagging groceries

Figure 1 - Stage I Self-Service Checkout System

Pay &Bag

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Pay &Bag

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Waiting Area forShoppers Ready

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Station 1 Station 2

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To Processing at Customer Service Desk

Exit

Pay &Bag

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Scan Pay Bag

Scan Pay Bag

Scan Pay Bag

Scan Pay Bag

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Figure 2 - Stage II Self-Service Checkout System

Problem Statement:Stop & Shop grocery stores have implemented the use of self-service checkout lines to reduce operating costs. This is accomplished by eliminating both a cashier and a food packaging associate normally required in each checkout line. Furthermore, by removing the cashier, who is typically located in part of the isle, the new self-service checkout systems can be narrower and therefore require less floor space. Although the self-service lines process shoppers a bit slower than the conventional checkout line, due to shoppers being unfamiliar with the system and inevitable hang-ups, total shopper throughput may be increased by being able to add more checkout lines in the same amount of space. Stop & Shop wants to know if they should install more self-service checkout lines to maximize shopper through put based on the floor space available. The focus of this study will be to determine the optimum number of self-service lines required to maximize shopper through put based on the floor space available in the checkout area.

Approach:An initial visit will be made to the Stop & Shop super market to accurately document the configuration of each checkout line. A Pro-Model simulation model will then be created based on the configuration schematic. A separate visit will be made to collect arrival and processing data for each checkout line configuration. This will include data from both of the full service checkout lines, 12 items or less and the unlimited lines, as well as data from both self-service checkout lines, again 12 items or less and the unlimited lines. Roughly 1 hour of data will be collected for each checkout line for a total of 4 hours of data. Data will be collected on a weekend to ensure minimal idle time in each of the checkout lines. A simulation will be run to baseline the current configuration and to determine the current maximum customer through put. An optimization routine will then be run, varying the number of individual checkout line configurations, to determine the optimum combination of full and self-service checkout lines.