[talks] Colloquium Speaker, Mon April 19th- David Sontag

[Nicole E. Wagenblast]

Approximate Inference in Graphical Models using LP Relaxations 
David Sontag, MIT 
Monday, April 19th, 2010- 4:30pm
Computer Science, Small Auditorium CS105

Graphical models such as Markov random fields have been successfully applied to a wide variety of fields, from computer vision and natural language processing, to computational biology. Exact probabilistic inference is generally intractable in complex models having many dependencies between the variables.

In this talk, I will discuss recent work on using linear programming relaxations to perform approximate inference. By solving the LP relaxations in the dual, we obtain efficient message-passing algorithms that, when the relaxations are tight, can provably find the most likely (MAP) configuration.

Our algorithms succeed at finding the MAP configuration in protein side-chain placement, protein design, and stereo vision problems. More broadly, this talk will highlight emerging connections between machine learning, polyhedral combinatorics, and combinatorial optimization.