M. Eng. project helps Foodnet Meals on Wheels Improve Service and Hold the Line on Costs
When ORIE Master of Engineering students undertook a project to help Foodnet improve its operations, the cost of fuel was not the major consideration of their work. However since then the price of gasoline has increased by about $1 per gallon and demand has grown substantially. Foodbank organizers nationwide are facing similar problems, according to a recent NPR segment.
But as a result of efficiencies that Foodnet gained by building on the students' work, the non-profit organization has been able to stay within their fuel and maintenance budget in an activity that is highly dependent on transportation and that has been facing increased demand.
Foodnet is a Tompkins County , New York activity organized to promote independent living by providing and delivering "Meals on Wheels" to those 60 years or over who are homebound and unable to prepare meals. Professor Emeritus William Tomek, Foodnet's Vice Chairman, approached ORIE in 2005 to ask for analytical assistance, at the suggestion of James Pratt, a Senior Research Associate and now a member of Foodnet's Board of Directors. Both Tomek and Pratt are in Cornell's Department of Applied Economics and Management.
Tomek asked: "Can Foodnet make better use of their food preparation and delivery resources?" Carolyn Arnold, a registered dietician who is Assistant Director of Foodnet, recalled that "Tompkins County had funded 2 additional drivers and the City of Ithaca made 2 additional vans available through the Community Development Block Grant program. These provided an incentive to optimize our operations."
More than two years later, the results are in. Recommendations of the Master of Engineering project have been successfully implemented, and have achieved most of the desired results. The project was carried out in the 2005-2006 academic year by Sebastien Desfriches-Doria, Hector Espinoza and David Rimshnick under the guidance of Professor Robert Bland and Dr. Mark Eisner.
The project focused on reducing the "delivery time window" (the time between the first and last delivery of the day) and on decreasing the time it takes to pack the food for delivery. Both of these objectives were accomplished, the first through the use of advanced route optimization software implemented by the team, and the second through a reorganization of the packing line that was based on testing alternatives in a computer simulation.
Although minimizing the time window gets meals delivered closer to the noon hour, it does not necessarily minimize travel distance, fuel cost, or maintenance cost. However the new routes did reduce all four quantities. For example the organization budgetted $32,000 for gasoline in 2006 but spent only $24,500 and maintenance costs dropped by a third from the previous year, largely as a result of the new routes and despite an increase in the number of clients.
|Foodnet workers pack hot lunches for delivery to clients on a redesigned line based on simulation experiments by the team. From left, Kent Moore, Gregory Turton, Mary Mente, John Yunker and Tim Andrews.|
The recommendations "meshed well with our thoughts," said Joe Fort, Food Service Operations Manager at Foodnet. "The outcome of the study helped us align our new routes, both geographically and time-wise. We also rethought how we served and packed our food. All in all, our goal of more timely delivery has been successful and has eliminated any mid-afternoon deliveries." According to Arnold, previously the growth in the number of clients served meant that some were not getting their midday meal until after 3 PM. "Now most of our routes are finished by 1:30 PM," she said.
To devise improved routes, the team turned to techniques related to the hard computational problem, known as the traveling salesman problem, of determining the sequence of stops on a sales person's route that minimizes the distance, time or cost to visit a list of geographically dispersed customers. They used commercial software that incorporates heuristics, or approximation techniques, to find the shortest single route connecting all of the clients. They then developed a technique to split that single route into several individual routes so as to minimize the longest time window for any of the delivery vans. (Related techniques were used by an M.Eng. project team in 2006-7 to develop improved bus routes for the Ithaca City School District.)
Building on a database of client information, Microsoft mapping and routing software, and their additional computational techniques, the team developed a computer system that Foodnet staff can use to produce route plans and adapt them to changes in the client population. "It is not hard to adjust routes because of the way the system is designed", according to Fort. Arnold was able to try different configurations to reduce changes, such as a different driver, that would be experienced by the clients. As a result "the transition went very well," said Steve Griffin, Executive Director of Foodnet. "The sensitivity analysis [facilitated by the software] permitted planning opportunities" as well, Griffin added. In reporting to Foodnet's Board, the team showed that that their routes have properties not far from what is theoretically the best that can be achieved, and also that there are diminishing returns from adding additional vehicles.
All three team members are currently professional logistics consultants. Team member Espinoza, who came to Cornell from Paraguay, is now working at Supply Chain Consultants, a Wilmington, DE, company founded by Cornell Ph.D. alumnus Harpal Singh. Espinoza said that the Foodnet staff "were very committed and helped us in every way they could to help us succeed." Desfriches-Doria, from France, now works on retailers' inventory problems for 4R Systems in Philadelphia, PA. He found that the project "helped me make the transition from the classes to my job as an OR analyst." Similarly Rimshnick, now at ZS Associates in Princeton, NJ, found the project "a unique and fulfilling way of transitioning my academic training to real-world solutions."
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