期刊名称：Conference on European Chapter of the Association for Computational Linguistics (EACL)
出版年度：2009
卷号：2009
出版社：ACL Anthology
摘要：An open problem in dependency parsing
is the accurate and efficient treatment of
non-projective structures. We propose to
attack this problem using chart-parsing
algorithms developed for mildly contextsensitive
grammar formalisms. In this paper,
we provide two key tools for this approach.
First, we show how to reduce nonprojective
dependency parsing to parsing
with Linear Context-Free Rewriting Systems
(LCFRS), by presenting a technique
for extracting LCFRS from dependency
treebanks. For efficient parsing, the extracted
grammars need to be transformed
in order to minimize the number of nonterminal
symbols per production. Our second
contribution is an algorithm that computes
this transformation for a large, empirically
relevant class of grammars.
