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.


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.


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.