Using DepPattern to Correct the PoS Tagged Input Text

DepPattern is provided with tools suited to correct errors of the input PoS tagged text. DepPattern allows a linguist to elabore syntactic rules in order to correct systematic mistakes made by the PoS tagger. For this purpose, we are provided with 3 new elements:

Let's see an example. Suppose that the PoS tagger systematically tag as a subordinate conjunction the word that following a noun, even if in this context that is, in general, a relative pronoun. To solve the problem, we can write a rule as follows:

Single : [NOUN] CONJ<lemma:that&type:S>

Corr: tag:PRO, type:R

%

This way, the information introduced by the operator ``Corr'' is used to change the head expression of the unary relation ``Single''. It substitutes tag PRO and type R for the information contained in the head (tag CONJ and type S). More precisely, this rule identifies as head a subordinate conjunction with lemma that following a noun (its context), and transform this head entry into a relative pronoun. Notice that there there is no dependent expression involved in the rule, since the relation type of ``Single'' is Head.

Pablo Gamallo 2009-06-22