Lexical relations

One of the essential features of the "Meaning Text" model (MTM) developed by I. A. Mel'chuk et. al. is the special lexicon or ECD ('explanatory and combinatory' dictionary). This component can be thought of as a collection independent thesaurus, and can be applied to improve the effectiveness of an information retrieval system.After outlining the MTM and related work, this paper briefly describes the SMART type of information retrieval system. Applicability of the above-mentioned lexicon to such a system is discussed. In particular, the list of lexical relations included in the ECD is expanded and organized to be more effective for retrieval, partially along the lines suggested by Evens and Smith.Finally, an experimental analysis of the utility of lexical relations in an information retrieval system is discussed. It is shown that lexical relations generally enhance system performance. When all lexical relations are considered in the comparison, the resulting performance is shown, by statistical methods, to make a significant improvement (up to 16.5% at a single recall level); when all lexical relations except for antonyms are considered, the improvement is even greater (up to 20.2% at a single recall level).