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<Paper uid="W99-0614">
  <Title>Hybrid Disambiguation of Prepositional Phrase Attachment and Interpretation</Title>
  <Section position="4" start_page="117" end_page="117" type="metho">
    <SectionTitle>
4 Evaluation
</SectionTitle>
    <Paragraph position="0"> Cross validation (see section 2.2) showed that hybrid disambiguation achieves for both prob- null scoring function scoredist lems, PP attachment and PP interpretation ambiguity, satisfying correctness results for all six prepositions (see Table 6): 88.6-94.4% for binary attachment ambiguities, 85.6-90.8% for all ambiguous attachments, and 75.0-84.2% for ambiguity degrees above 2 (leading to the multiple PP attachment problem).</Paragraph>
    <Paragraph position="1"> Comparison of the interpretation results is impossible as these are the first cross-validated results for PP interpretation. But 83.3-92.5% correctness for prepositions with more than one reading seems very promising.</Paragraph>
    <Paragraph position="2"> Comparison of the attachment results is possible, but difficult. One reason is that the best reported disambiguation results for binary PP attachment ambiguities (84.5%, (Collins and Brooks, 1995); 88.0% using a semantic dictionary, (Stetina and Nagao, 1997)) are for English. Because word order is freer in German than in English, the frequency and degree of attachment ambiguity is probably higher in German. There are only few evaluation results for German: (Mehl et al., 1998) achieve 73.9% correctness for the preposition 'mit' ('with'/'to'/...) using a statistical lexical association method.</Paragraph>
    <Paragraph position="3"> Of course, the evaluation corpus is not large (720 sentences); so, the results reported in this paper must be treated with some caution. But as the selected prepositions show diverse numbers of readings (1-9, see Table 4) and the results are cross-validated, it is likely that the reported results will not deteriorate for larger corpora. null</Paragraph>
  </Section>
class="xml-element"></Paper>