Information Technology Reference
In-Depth Information
A Framework for Interpreting Bridging Anaphora
Parma Nand and Wai Yeap
School of Computing and Mathematical Sciences, Auckland University of Technology,
Auckland, New Zealand
{
pnand,yweap
}
@aut.ac.nz
Abstract.
In this paper we present a novel framework for resolving bridging
anaphora. We argue that anaphora, particularly bridging anaphora, is used as
a shortcut device similar to the use of compound nouns. Hence, the two natu-
ral language usage phenomena would have to be based on the same theoretical
framework. We use an existing theory on compound nouns to test its validity
for anaphora usages. To do this, we used human annotators to interpret indirect
anaphora from naturally occurring discourses. The annotators were asked to clas-
sify the relations between anaphor-antecedent pairs into relation types that have
been previously used to describe the relations between a modifier and the head
noun of a compound noun. We obtained very encouraging results with an average
Fleiss's
κ
value of 0.66 for inter-annotation agreement. The results were evalu-
ated against other similar natural language interpretation annotation experiments
and were found to compare well.
In order to determine the prevalence of the proposed set of anaphora relations
we did a detailed analysis of a subset 20 newspaper articles. The results obtained
from this also indicated that a majority (98%) of the relations could be described
by the relations in the framework. The results from this analysis also showed the
distribution of the relation types in the genre of news paper article discourses.
Keywords:
Anaphora resolution, Noun phrase anaphora, Discourse structure,
Noun compounds, Noun phrases.
1
Introduction
The term
anaphora
originated from an ancient Greek word “
αυαφoρα
” which means
“the act of carrying back upstream”. In the context of natural language processing, the
term
anaphor
is a reference which points back to a noun that has been mentioned
previously in the text being processed. The referred noun is called the
antecedent
.The
anaphor can be the same noun as the antecedent, a variation of the noun or a completely
different noun. A common form of anaphor is one in which the anaphor is used as a
co-reference pointer to the antecedent noun. This is true in the case of pronouns where
the pronoun has a one-to-one relation with the antecedent. It is also true in the case of
some noun phrases (NPs) where the anaphoric noun directly co-refers to the antecedent
(eg. James Smith/Mr Smith). However a noun can also be used as an indirect reference
to a previously mentioned noun. As an example consider the following excerpt:
