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<Paper uid="J94-4002">
  <Title>An Algorithm for Pronominal Anaphora Resolution</Title>
  <Section position="7" start_page="558" end_page="559" type="concl">
    <SectionTitle>
7. Conclusion
</SectionTitle>
    <Paragraph position="0"> We have designed and implemented an algorithm for pronominal anaphora resolution that employs measures of discourse salience derived from syntactic structure and a simple dynamic model of attentional state. We have performed a blind test of this algorithm on a substantial set of cases taken from a corpus of computer manual text and found it to provide good coverage for this set. It scored higher than a version of Hobbs' algorithm that we implemented for Slot Grammar.</Paragraph>
    <Paragraph position="1"> Results of experiments with the test corpus show that the syntax-based elements of our salience weighting mechanism contribute in a complexly interdependent way to the overall effectiveness of the algorithm. The results also support the view that attentional state plays a significant role in pronominal anaphora resolution and demonstrate that even a simple model of attentional state can be quite effective.</Paragraph>
    <Paragraph position="2"> The addition of statistically measured lexical preferences to the range of factors that the algorithm considers only marginally improved its performance on the blind test set. Analysis of the results indicates that lexical preference information can be useful in cases in which the syntactic salience ranking does not provide a clear decision among the top candidates, and there is a strong lexical preference for one of the less salient candidates.</Paragraph>
    <Paragraph position="3"> The relatively high success rate of the algorithm suggests the viability of a computational model of anaphora resolution in which the relative salience of an NP in discourse is determined, in large part, by structural factors. In this model, semantic and real-world knowledge conditions apply to the output of an algorithm that resolves pronominal anaphora on the basis of syntactic measures of salience, recency,  Computational Linguistics Volume 20, Number 4 and frequency of mention. These conditions are invoked only in cases in which salience does not provide a clear-cut decision and/or there is substantial semantic-pragmatic support for one of the less salient candidates. 27</Paragraph>
  </Section>
class="xml-element"></Paper>