<?xml version="1.0" standalone="yes"?>
<Paper uid="C00-1031">
  <Title>An Empirical Investigation of the Relation Between Discourse Structure and Co-Reference</Title>
  <Section position="7" start_page="212" end_page="212" type="evalu">
    <SectionTitle>
3.3.2 Results
</SectionTitle>
    <Paragraph position="0"> Figure 8 shows the Discourse-VT-k and Linear-k efforts computed over all referential expressions in the corpus and all ks. It is possible, for a given referent a and a given k, that no co-referential link exists in the units of the corresponding EDRAa.. In this case, we consider that the effort is equal to k. As a consequence, for small ks the effort required to establish co-referential links is similar for both theories, because both can establish only a limited number of links. However, as k increases, the effort computed over the entire corpus diverges dramatically: using the Discourse-VT model, the search space for co-referential links is reduced by about 800 units for a corpus containing roughly 1200 referential expressions.</Paragraph>
    <Paragraph position="1">  A Paired-Samples T Test was performed for each k. For each text in the corpus and each k, we determined the effort of both VT-k and Linear&amp; models to establish correct co-referential links in that text. For all ks the difference in effort was statistically significant. For example, for k = T, we obtained the values t = 3.5l, df = 29, P = 0.001. These results are intuitive: because EDRAs are treated as ordered lists and not as sets, the effect of the discourse structure on establishing correct co-referential links is not diminished as/,' increases.</Paragraph>
  </Section>
class="xml-element"></Paper>