期刊名称：Conference on European Chapter of the Association for Computational Linguistics (EACL)
出版年度：2011
卷号：2011
出版社：ACL Anthology
摘要：We present a novel pruning method for
context-free parsing that increases efficiency
by disallowing phrase-level unary productions
in CKY chart cells spanning a single word.
Our work is orthogonal to recent work on
¡°closing¡± chart cells, which has focused on
multi-word constituents, leaving span-1 chart
cells unpruned. We show that a simple discriminative
classifier can learn with high accuracy
which span-1 chart cells to close to
phrase-level unary productions. Eliminating
these unary productions from the search can
have a large impact on downstream processing,
depending on implementation details of
the search. We apply our method to four parsing
architectures and demonstrate how it is
complementary to the cell-closing paradigm,
as well as other pruning methods such as
coarse-to-fine, agenda, and beam-search pruning.
