A Study of Relevance Propagation in Large Topic Ontologies

XAMENA, EDUARDO; BRIGNOLE, NÉLIDA BEATRIZ; MAGUITMAN, ANA GABRIELA

JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY

JOHN WILEY & SONS INC

Lugar: New York; Año: 2013 vol. 64 p. 2238 - 2255

1532-2882

Topic ontologies or web directories consist of large collections of links to websites, arranged by topic in different categories. The structure of these ontologies is typically not flat, because there are hierarchical and nonhierarchical relationships among topics. As a consequence, websites classified under a certain topic may be relevant to other topics. Although some of these relevance relations are explicit, most of them must be discovered by an analysis of the structure of these ontologies. This article proposes a family of models of relevance propagation in topic ontologies. An efficient computational framework for inferring implicit relevance relations is described. Nine different models were computed for a portion of the Open Directory Project graph consisting of more than half a million nodes and approximately 1.5 million edges of different types. The models were initially compared from a quantitative perspective by considering the number of inferred relations. This allowed us to distinguish the more conservative models from the less conservative ones, inducing a partial order on the set of models. A user study was carried out to compare the most promising models. It is found that some general difficulties rule out the possibility of defining flawless models of relevance propagation that take into account only structural aspects of an ontology. However, there is a clear indication that including transitive relations induced by the nonhierarchical components of the ontology results in relevance propagation models that are superior to more basic approaches.