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

8.4. Using Onto.PT 155
Uma população (grupo com o mesmo tipo de organismo) pode adaptar-se através da
evolução (desenvolvimento gradual) durante muitas .
(a) gerações (c) adequações
(b) tradições (d) maiorias
Figure 8.8: Cloze question answered correctly using each resource.
for improving the performance of NLP tasks where it is important to compute
the similarity between words or concepts. Moreover, the results are better using
CARTÃO and PAPEL than using Onto.PT, which suggests that, for this specific
task, a lexical network is more adequate than a wordnet. No strong conclusions can
be taken because, even though very similar, the algorithms used are also different.
For instance, the algorithm using Onto.PT is more complex and relies on WSD,
which can be an additional source of noise.
Another conclusion that emerges from this exercise is that merging knowledge
from different resources originates better results. This explains why the accuracy
using CARTÃO is higher than using only parts of it, more precisely, PAPEL, DA,
or Wiktionary.PT.
Finally, we should add that our results are much lower than the best accuracy
for answering TOEFL synonymy questions automatically with the help of a
lexicon (78.75%, by Jarmasz and Szpakowicz (2003)). However, the task we have
performed is certainly more complex, and cannot be blindly compared. In the future,
it would be interesting to try both Onto.PT and CARTÃO in the synonymy
problem, analogy problems, and others, as solving cross-words. So far, we did not
find usable datasets with such resources for Portuguese, but we will keep looking for
them.