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Ant Colonies in the Skies

“Discoveries and Breakthroughs in Science” is a producer of short TV clips on results in math and science. INFORMS is involved with them, and is seeking story ideas to pitch to them.

This month’s mathematics story is about using ant colony optimization to help run an airport, with an emphasis on the gate assignment problem.

“It’s sort of like a colony of individuals trying to move through a maze with all of the other individuals present, arriving and departing and trying to do it as fast as they can,” Douglas Lawson, Ph.D., a financial analysis manager at Southwest Airlines in Dallas, Texas, told Ivanhoe.

The software program uses swarm theory, or swarm intelligence — the idea that a colony of ants works better than one alone. Each pilot acts like an ant searching for the best airport gate. “The pilot learns from his experience what’s the best for him, and it turns out that that’s the best solution for the airline,” Dr. Lawson explains.

I’m not a huge fan of Ant Colony Optimization: it has always seemed overblown to me. But the proof is in the results, so if this does work better than alternative approaches, then that’s great. I have not found Lawson’s work on this on the web, but gate assignment has been tried with ACO (see here and here) and other forms of swarm intelligence, and Lawson is the “Manager of Process, Forecasting, and Simulations” at Southwest, an admirable airline, so it is interesting to see him using this in practice.

One thing bothered me and one thing I found humorous. First, Lawson and his team are described as “financial analysts”. Is the “Manager of Process, Forecasting and Simulations” a financial analyst? My guess is that the TV producers decided not to make the big step and call him “operations researcher” so they went with a word they thought the audience would know.

The humorous part comes in the background information where they describe swarm intelligence:

HOW DO SWARMS OPERATE? How do ants find a route to a food source? Each ant follows the strongest pheromone (chemical) trail left by other ants. If this process is repeated frequently enough, they will find the best route through trial and error. If ants become isolated from their group, they end up running around in circles, following their own pheromone trail until they die of exhaustion. This behavior, called “swarm intelligence,” …

I would hate to be on the plane that gets separated from the others!

{ 2 } Comments

  1. Krishnan | April 5, 2008 at 4:57 pm | Permalink

    Speaking of ant colonies, the May issue of the
    Atlantic has an article by James Fallow on DayJet – the air taxi service where they use ant colony optimization to determine operations along with agent based modeling. As with any general issue magazine its very light on the technical aspects but he does an adequate job of describing the process.

  2. Michael Trick | April 5, 2008 at 5:21 pm | Permalink

    I’ll check it out as soon as I can! I believe the Georgia Tech gang were involved in the math side of Day Jet’s planning and scheduling.