Title: Beyond MaltParser - Advances in Transition-Based Dependency Parsing
Speaker: Joakim Nivre (Uppsala University)
Place: Science Center. Rm 4102, CUNY Graduate Center. 5th Ave & 34th St.

Abstract:

The transition-based approach to dependency parsing has become popular
thanks to its simplicity and efficiency. Systems like MaltParser achieve
linear-time parsing with projective dependency trees using locally trained
classifiers to predict the next parsing action and greedy best-first search
to retrieve the optimal parse tree, assuming that the input sentence has
been morphologically disambiguated using a part-of-speech tagger. In this
talk, I survey recent developments in transition-based dependency parsing
that address some of the limitations of the basic transition-based approach.
First, I show how globally trained classifiers and beam search can be used
to mitigate error propagation and enable richer feature representations.
Secondly, I discuss different methods for extending the coverage to
non-projective trees, which are required for linguistic adequacy in many
languages. Finally, I present a model for joint tagging and parsing that
leads to improvements in both tagging and parsing accuracy as compared to
the standard pipeline approach.

Bio:

Joakim Nivre is Professor of Computational Linguistics at Uppsala
University. He holds a Ph.D. in General Linguistics from the University
of Gothenburg and a Ph.D. in Computer Science from Växjö University.
Joakim?s research focuses on data-driven methods for natural language
processing, in particular for syntactic and semantic analysis. He is one
of the main developers of the transition-based approach to syntactic
dependency parsing, described in his 2006 book Inductive Dependency
Parsing and implemented in the MaltParser system. Joakim?s current
research interests include the analysis of mildly non-projective
dependency structures, the integration of morphological and syntactic
processing for richly inflected languages, and methods for cross-framework
parser evaluation. He has produced over 150 scientific publications,
including 3 books, and has given nearly 70 invited talks at conferences
and institutions around the world. He is the current secretary of the
European Chapter of the Association for Computational Linguistics.