[Colloquium] TTIC Talks: Dipanjan Das, CMU

[Liv Leader]

When:     Tuesday, February 14 @ 1 p.m.

Where:   TTIC Conference Room #526, 6045 S. Kenwood Avenue, 5th Floor

Who:      Dipanjan Das, CMU

Title:       Robust Shallow Semantic Parsing of Text

Abstract:

In this talk, I will focus on data-driven models for semantic structure
prediction following frame semantics (Fillmore, 1982), a linguistic theory
that describes predicate-argument relationships and emphasizes the
abstraction of predicate meaning into semantic frames. Our method exploits
rich information provided by linguists in the form of a lexicon (Fillmore
and Baker, 2010), as well as a small amount of annotated data, to
automatically find disambiguated semantic frames of lexical predicates
present in a sentence. A frame represents semantic knowledge and requires
semantic roles that are fulfilled by arguments, in the form of words and
phrases within the sentence. After disambiguating each predicate to the
frame it evokes, our method finds the frame's arguments collectively via
joint inference, making use of dual decomposition. Large amounts of
annotated data for this task are unavailable; to this end, we model latent
structure and apply semi-supervised learning, resulting in more robust
models with broader coverage. Frame semantics is richer than the
representation used in popular semantic role labeling systems (Kingsbury
and Palmer, 2002) but less domain-specific than semantic parsers based on
logical form (Ge and Mooney, 2005; Zettlemoyer and Collins, 2005); it
represents a viable "middle ground" for data-driven semantic analysis of
text. Compared to previous work, our method makes fewer independence
assumptions and significantly outperforms past state of the art.

Host: Karen Livescu, klivescu at ttic.edu

-- 
Liv Leader
Human Resources Coordinator

Toyota Technological Institute Chicago
6045 S Kenwood Ave
Chicago, IL 60637
Phone- (773) 702-5033
Fax-     (773) 834-9881
Email-  lleader at ttic.edu <jam at ttic.edu>
Web-   www.ttic.edu
<http://www.ttic.edu/>
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