Delivering Optimal Solutions Overnight (or Better)
Daryl Pereira 270002AW8D firstname.lastname@example.org | | Tags:  ilogdialog optimization
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You probably know that FedEx Express is the world's largest express transportation company; they move 3+ million packages daily, using an air fleet of nearly 700 aircraft (flying through ten hubs worldwide) and a ground delivery fleet of over 44,000 vehicles. Would it be any surprise that they face huge planning problems? Kevin Campbell gave us an inside look at how they apply Optimization to their operations.
Their planning goes from ultra-long range (3 to 20 years) for fleets and facilities, down to tactical decisions. Applications using CPLEX include fleet planning, vehicle allocation, hub ground support equipment, aircraft arrival/departure timing, and manpower planning. A typical model attempts to minimize pound-miles, subject to various constraints at hubs and ramps Kevin gave examples of Mixed Integer Programming models with over 100,000 constraints and 1,000,000 variables, of moderate density (8 to 10 million nonzeros). And that is after Presolve removes any obvious redundancies and trivial bounds!
FedEx Express has made meaningful use of the technical support offered by ILOG. Performance tuning on models like these, by using the advanced features CPLEX makes available to power users, helped get solution times down from the weekend range to more like overnight. Definitely a leading-edge model to put into production usage, and it makes me really happy to hear of their success.