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<Paper uid="C96-1078">
  <Title>Alignment of Shared Forests for Bilingual Corpora</Title>
  <Section position="7" start_page="463" end_page="464" type="concl">
    <SectionTitle>
8 Results and Future Directions
</SectionTitle>
    <Paragraph position="0"> The. era:rent implement~tion aligns trees 63 times faster than our previous program (Grishman, 199d), with a 2.3% inq)rovement in pre(:ision. 1deg We expect line-tuning el' the pa.rameters in our procedures to improve our performance. We expect to gain greater efficiency if all COi\[HIHOH IlOdeS between forests are s\]lare(l, rather than .just the NPs. Another efficiency inlprovcment will be aehieved by factoring all ambiguity into the parse tree, as in (Matsumoto eta\]., 1993). In our cur rent approach, disjunctions are r(:prcse.ntetl only at; the root level.</Paragraph>
    <Paragraph position="1"> In order to inq)rovc the precision of alig,tment, we plan to ext)erimenl, with w~rying the values of the Lex fmletions mid penali, ies in our scor.ing algorithm and exl)anding our bilh,gua\] dictio nnry. We will also experiment with the non--gr('.edy algorithm discussed al)ove and a th)nthmn(:(.'.</Paragraph>
    <Paragraph position="2"> preserving algorithm (~ less consl.rained version of the algorithni which we have omitted due to .space limitations). In the dominance-preserving algorithm we relax the requirement of h:a-preserw~.tion, and require the l)rcserw~,tion of the (\]omi\]~ancc rc lationship between lm(les: If', for two nodes a C- 7' a~d b C 7', a dominates b ((telloted ~ts a ~ b), thell for f(a) ~ 7&amp;quot; and f(b) C '1&amp;quot;, f(a) j@).</Paragraph>
    <Paragraph position="3"> The kh:a which makes it possible to align s(m~ tenets quickly is that we place restrictions on the ways in which we align the parse trees. W('.</Paragraph>
    <Paragraph position="4"> tdeg'I'ihe dynamic l)rogreumniug algorithm accounts for ml approximately 600% iucrc~tsc ill speed of align\]nent a rough estimate sin(:e much of Chc I)rogrmn has been r(&gt;implemcntcd.</Paragraph>
    <Paragraph position="5">  disallow ~,lignnmnts which viobtte the I,(:A constra.itd; or I,h(~ (\[o~nin~m(:(~ r('xluiren,enl. , and per\[nil oltly one to ()ira a.lignm(ml.s I)(~l.w(~en no(los. Some cases wh(:rc on(: ~\[~ight. posit a (:orr(~sl)Onden(:e I)el, wcen a single node :~: ~m(I ~ group of</Paragraph>
    <Paragraph position="7"> ~dignmcnt I)etwcen a: and ,~ti, for some. j, \] &lt; j _&lt; n, where 95 dominates the rem~dning no(les in (l. We (Io not consider other types of (me-to-many ~:dignlll(':lltS. null</Paragraph>
  </Section>
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