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LINDO Cures Big Tire Problems |
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-- Application Leads to Award Winning Paper
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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
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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.
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