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LINDO Cures Big Tire Problems

-- Application Leads to Award Winning Paper

Imagine a single tire taller than a Chevy Pickup standing on end, weighing a little more than fourteen Toyota Camrys, and selling for about twice the price of a Cadillac DeVille. Suffice it to say, Bridgestone/Firestone Off-The-Road (BFOR) tires aren't for your average Sport Utility Vehicle. Finding the best way to assign these extra large tires to molds and molds to curing ovens to maximize production was the enormous problem the plant's production scheduler faced on a daily basis

Taking into account customer orders, mold and oven sizes, critical mold stacking restrictions, various curing times, as well as the standard requirement for quick solution times made this an extremely large and challenging integer programming problem to solve. However, using a column generation procedure hooked to LINDO and incorporating an innovative combination of preprocessing, cutting plane technology, and other techniques, a scheduling system was designed that produces about 7% more tires than the manual scheduling process BFOR was previously using.

After evaluating the new schedules, Tom Lykens, production scheduler for BFOR for over 20 years, was well pleased, "...this is great,...I like this,...you people have no idea what I am up against every morning..." With the significant boost in production of tires costing up to $70,000 each, it goes without saying that BFOR's top management was particularly happy.

Mr. Lykens and BFOR's management were not alone in their praise of the application. The paper, "A Tire Scheduling System for Bridgestone/Firestone Off-The-Road" authored by Zeger Degraeve of Katholieke Universiteit Leuven and Linus Schrage of The University of Chicago, was published in the November-December 1997 issue of Operations Research. It was the winner of the Association of European Operational Research Societies prize for Best Applied Paper of the Year 1997.

The paper won the award because it demonstrated a real-life benefit to the company. It was praised for its rigorous mathematical foundations using and extending advanced operations research techniques. It was also recognized for the originality of the application. The prize was conferred to the authors at the Joint International EURO XV/INFORMS XXXIV Meeting in Barcelona, Spain.