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INFORMS: Perspectives – Eoin O’Mahony on Bikesharing in New York City

by David Morrison on November 10th, 2014

The first three sessions I’ve attended at INFORMS this year have all been student paper competitions; in my opinion, the paper competitions are some of the very best talks at the Annual Meetings. The nice thing is that there are so many of them! I went to the Doing Good with Good OR and Nicholson presentations, but there’s also a best-paper competition hosted by SPPSN (Public Programs, Services, and Needs), the Junior Faculty Interest Group (JFIG) competitions, and many others. I definitely encourage you to try to attend some of these competitions to listen to some highly-skilled presenters talk about cutting-edge research being done in OR.

However, many of these talks are already over, so if you didn’t get a chance to see them, I’m highlighting one here in my first entry for INFORMS: Perspectives. So without further ado, here we go!


Eoin (pronounced Owen, not Oyn, and most certainly not E-oyn) O’Mahony is a fifth-year PhD student at Cornell University, working under David Shmoys (who, by the way, is an INFORMS Fellow!). This is his first time at INFORMS, and he’s off to a great start as a finalist in the Doing Good with Good OR student prize competition.

In his talk this morning, entitled Smarter Tools for (Citi)bike Sharing, he described his research efforts to optimize the bike-sharing economy in New York City. In short, Citibike is an organization that provides bicycles to commuters in NYC on a subscription basis to commute around Manhattan (to work, to the grocery store, and particularly vexing from an optimization perspective, the bars in Williamsburg on Friday afternoon). The problem is that sometimes these bikes don’t always return to where they’re needed, so Citibike has to rebalance the bike loads on a daily basis.

I sat down with Eoin after his talk to get some more perspective on the problem: “My work is on applying analytics, optimization, and data-driven thinking to the New York City bikeshare system,” he told me. The primary concern is managing imbalance by answering the following three questions:

  1. Where do bikes need to be?
  2. When do they need to be there?
  3. How do they get there?

Eoin applies a number of optimization techniques to solve this problem that will be very familiar to anyone in OR: continuous time Markov chains, linear programming, integer programming techinques, and approximation algorithms all feature prominently in his solution methods. And to great effect: in an article published in Science, Michael Pellegrino, the director of operations for the New York City bikeshare system, says that this work provides the “overarching vision for how we like our system to look.”

And this is what Eoin says is the most rewarding part of his research: “Being able to see and make an impact on the New York City landscape.” It hasn’t always been easy—bridging the gap between theory and practice, Eoin says, is quite difficult. He’s needed to find a model that is both computationally tractable, but also possible to reason about theoretically. And to top it off, they need buy-in from the stakeholders involved (I suspect this is another familiar refrain to OR folks here). Asked how to navigate all these roadblocks effectively, Eoin says, “Make yourself useful, quickly.” When I asked how one goes about that, he laughed and said, “Well, that’s the tricky bit, isn’t it?”

All in all, it sounded to me like Eoin is doing some really great work in New York City, and also in the INFORMS community. As we were attempting to find a spot to sit and talk, we commiserated on the multi-objective problem of “wanting to meet up with colleagues and friends” and “finding a place to sit down and think for a minute or two”—something that’s particularly challenging in this dynamic and exciting city. However, if you are interested in knowing how to implement a bikeshare system in your city, Eoin O’Mahony can solve that for you, so make sure to track him down this week. And best of luck in the DGWGOR competition! Head to the prize ceremony tonight to see the results!

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