A Wordnet from the Ground Up

4.5. Hybrid Combinations 1374.5.2 Benefits of classifier-based filtering for wordnet expansionThe MSR for the experiments and the values of all attributes were generated fromtwo corpora combined – both were used in other our experiments. Their more detaileddescription can be found in Section 3.4.5. One was IPIC with ≈ 254 milliontoken. The other was the corpus of the daily Rzeczpospolita with ≈ 116 million token(Rzeczpospolita, 2008).MSR RW F was the same as that proposed by Piasecki et al. (2007b). Its constructionwas based only on two types of lexico-morphosyntactic constraints: modification bya specific adjective or adjectival participle (AdjC in Section 3.4.3, page 67), and coordinationwith a specific noun (NcC).All nouns, adjectives and adjectival participles from the combined corpora wereused accordingly as the lexical elements of constraint instances. MSR RW F provideda description of 13298 nominal LUs and achieved the accuracy of almost 91% inWBST+H, see Section 3.3.1 generated from the plWordNet version June 2008.We used plWordNet as the main source of training/test examples. Following themain line of the experimental paradigm of (Snow et al., 2005), we generated fromplWordNet two sets of LU pairs: Known Hypernyms [KH] and Known Non-Hypernyms[NH]. Our goal is to support linguists by presenting relevant pairs of LUs. Similarlyto (Snow et al., 2005) we constructed the set of Known Hypernyms from LU pairs〈a, b〉 where b is a direct hypernyms of a or a hypernymic ancestor of a. In contrastwith (Snow et al., 2005), we allowed only for the limited hypernymic distances in allKH sets. Aiming at a tool to support linguists, we did not want remote associationsamong classified positively LU pairs.Hypernymy path length guided experiments with two different divisions of the twogroups. We wanted to investigate to what degree we can distinguish closer and moreremote hypernyms. We generated four data sets from the plWordNet version April2008:H the set of pairs: direct hypernym/hyponym (2967 pairs) – in all experiments H wasincluded in KH,P2 pairs of LUs connected by the path of the two arcs in the hypernymy graph –P2 was included in KH (2060 pairs),P3 pairs of LUs connected by a path of three or more hypernymy arcs, in NH (1176pairs),R pairs of words randomly selected from plWordNet in such way that no direct hypernymypath connects them, NH (55366 pairs, including co-hyponyms).After initial experiments, we noticed that the border space between typical elementsof KH and NH is not populated well enough, especially considering its importance