A Wordnet from the Ground Up

134 Chapter 4. Extracting Relation Instances8. recall of modification by genitive – the recall of repeating b’s features, whichexpress modification by a specific noun in genitive, by the similar features of a,9. global frequency of a – the total frequency of a in the corpus,10. global frequency of b – the total frequency of b in the corpus,11. number of significant adjectival features of a – the number of adjectival featureswhose co-occurrence with a is statistically significant, e.g., according to thet-score measure,12. number of significant adjectival features of b – the number of adjectival featureswhose co-occurrence with b is statistically significant,13. co-occurrence in text window of a and b – the frequency of a and b co-occurringin the same wider text window, e.g., of the size t w = ±50 tokens,14. significance of co-occurrence in text window of a and b – the statistical significanceof a and b co-occurring in the same text window, e.g., on the basis of thet-score measure,15. adjectival specificity of a – after Caraballo (1999), calculated here (see formula4.12) as the average number of adjectival features for a single occurrence of ain the corpus,16. adjectival specificity of b – calculated according to formula 4.12,17. adjectival specificity ratio – the ratio of a’s adjectival specificity to b’s adjectivalspecificity.In subsequent discussion, we use the term relevant LUs jointly for near-synonyms,close hypernyms and close hyponyms that occur on MSRlist (a,k) . From the point ofview of the intended expansion of a wordnet, all three relations jointly mark potentialplacements of a in the hypernymy structure, so they may be relevant to the linguist’swork.We pass to the classifier only those LUs whose value of semantic relatedness ishigher in comparison to other pairs of LUs, defined as by MSRlist (a,k) for some predefinedk , but the exact value of MSR is still important. It is more likely that a relevantLU b will have a higher value of MSR RW F (a, b) – the attribute 1 – than non-relevantLUs. It is hard to find a global threshold for the MSR RW F values guaranteeing someaccuracy, but in the case of particular MSRlists (a,k) some characteristics points can beobserved quite often. So we kept the MSR RW F value as an attribute for a classifierto combine with the other information.