Onto.PT: Towards the Automatic Construction of a Lexical Ontology ...

6.5. Discussion 111
Another contribution of this part of the work is that TeP, originally made for
Brazilian Portuguese, is enriched with words from dictionaries whose entries contain,
mainly 3 , words from European Portuguese. Therefore, besides being larger, the
new thesaurus has a better coverage of European Portuguese than TeP. Also, once
again due to its public domain character, the resulting thesaurus is another suitable
alternative to replace OpenThesaurus.PT as the thesaurus of the OpenOffice word
processor.
One limitation of the work presented here is the amount of observation labour
required to select the best assignment settings. An alternative would be to develop a
procedure to learn automatically the best measures and thresholds for associating a
synpair to a synset. Given that we already have a small gold resource, a supervised
learning approach, would suit this purpose. A simple linear classifier, such as a
perceptron (Rosenblatt, 1958) would probably be enough to, given a set of labelled
correct and incorrect examples for each assignment, learn the best threshold. This
will be devised as future work. Also, in order to get more reliable results, the gold
resource should as well be augmented. As it currently contains only nouns, in the
future, especially special attention should be given to the inclusion of verbs and
adjectives.
3 Wiktionary.PT covers all variants of Portuguese, and PAPEL contains a minority of words in
other variants of Portuguese, including Brazilian, Angolan and Mozambican.