Big Brother — Learning and Inferring Transportation Routines

Last week I went to AAAI-04 in San Jose. On Wednesday, the “outstanding paper” award winner was presented. It should also be the “scariest future technology paper”. Here’s abstract (emphasis mine):

L. Liao, D. Fox, and H. Kautz. Learning and Inferring Transportation Routines. Proc. of the National Conference on Artificial Intelligence (AAAI-04).
Abstract
This paper introduces a hierarchical Markov model that can learn and infer a user’s daily movements through the community. The model uses multiple levels of abstraction in order to bridge the gap between raw GPS sensor measurements and high level information such as a user’s mode of transportation or her goal. We apply Rao-Blackwellised particle filters for efficient inference both at the low level and at the higher levels of the hierarchy. Significant locations such as goals or locations where the user frequently changes mode of transportation are learned from GPS data logs without requiring any manual labeling. We show how to detect abnormal behaviors (e.g. taking a wrong bus) by concurrently tracking his activities with a trained and a prior model. Experiments show that our model is able to accurately predict the goals of a person and to recognize situations in which the user performs unknown activities.[The full text can be downloaded from here]

I saw the presentation and the method is pretty cool, but also kinda scary. From 30 days of continuous GPS traces they were able to build a model of a user’s movements around Seattle, including the locations of his grocery store and several of his friends’ houses, and predict, in real-time, the user’s most-likely destination when travelling around the city.

The authors present the method as part of a handheld wireless assistant for the elderly that could, for example, tell them when they got on the wrong bus. To be fair, I’ve met Dieter Fox, and I don’t think the he or his students have any nefarious ulterior motives. That said, once something like this is published there’s nothing to stop, say, your cell-phone provider from implementing it and integrating it with their location services. Many of us, including me, are carrying around little network-connected GPS units in our pockets at all times. I have Sprint’s location services turned “off”, but my location is still available to 911, so I wonder if it’s really hidden from Sprint’s network.

Maybe David Brin is right, and technology will soon make privacy a thing of the past. He has an article in Salon this month on that topic, suggesting that the way for us to protect our liberty is not to jealously guard our privacy (a losing battle), but to make sure that we the people are empowered just as much to watch as to be watched.

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