Exploring Richer Sequence Models in Speech and Language Processing

July 17, 2012
Eric Fosler-Lussier | The Ohio State University

Conditional and other feature-based models have become an increasingly popular methodology for combining evidence in speech and language processing. As one example, Conditional Random Fields have been shown by several research groups to provide good performance on several tasks via discriminatively training weighted combinations of feature descriptions over input. CRFs with linear chain structures have been useful for sequence labeling tasks such as phone recognition or named entity recognition. As we start to tackle problems of increasing complexity, it makes sense to investigate models that move beyond linear-chain CRFs in various ways – for example, by considering richer graphical model structures to describe more complex interactions between linguistic variables, or using CRF classifiers within a larger learning framework.

In this talk, I will describe recent research projects in the Speech and Language Technologies (SLaTe) Lab at Ohio State; each takes the basic CRF paradigm in a slightly different direction. The talk will describe two models for speech processing: Boundary-Factored CRFs, an extension of Segmental CRFs that allows for fast processing of features related to state transitions, and Factorized CRFs, which we used to investigate articulatory-feature alignment. I will also discuss how CRFs play a role in a semi-supervised framework for event coreference resolution within clinical notes found in electronic medical records.

Joint work with Yanzhang He, Rohit Prabhavalkar, Karen Livescu, Preethi Raghavan, and Albert Lai

Speaker Details

Eric Fosler-Lussier is an Associate Professor of Computer Science and Engineering, with a courtesy appointment in Linguistics, at The Ohio State University. After receiving a B.A.S. (Computer and Cognitive Science) and B.A. (Linguistics) from the University of Pennsylvania in 1993, he received his Ph.D. in 1999 from the University of California, Berkeley, performing his dissertation research at the International Computer Science Institute under the tutelage of Prof. Nelson Morgan. He has also been a Member of Technical Staff at Bell Labs, Lucent Technologies, and a Visiting Researcher at Columbia University. In 2006, Prof. Fosler-Lussier was awarded an NSF CAREER award, and in 2010 was presented with a Lumley Research Award by the Ohio State College of Engineering. He is also the recipient (with co-author Jeremy Morris) of the 2010 IEEE Signal Processing Society Best Paper Award. He is a member of the Association for ComputationalLinguistics, the International Speech Communication Association, and a senior member of the IEEE.