Building up ontologies with property axioms from English wikipedia

Large-scale ontologies have received much attention in various fields such as information retrieval, data integration, and question answering. However, since it is costly to construct and maintain large-scale ontologies manually, several ontology learning methods from Wikipedia have been proposed. YAGO and DBpedia are famous examples of large-scale ontologies automatically constructed from multilingual Wikipedia. However, there is room to extract from Wikipedia many kinds of relationships that are not included in YAGO or DBpedia. Previously, we proposed a method for constructing large-scale ontologies named Japanese Wikipedia Ontology (JWO) from Japanese Wikipedia. Since JWO has been constructed using several methods that are different from the extracting methods of YAGO and DBpedia, it is possible to extract relationships that do not exist in YAGO or DBpedia by using these methods. However, some of the methods are Japanese language-dependent, and cannot be applied directly to English Wikipedia. In this paper, we propose methods for constructing large-scale ontologies named English Wikipedia Ontology (EWO) from English Wikipedia. To achieve this, we have modified the Japanese language-dependent methods of JWO and extended several methods for extracting property axioms. EWO includes Is-a relations (rdfs:subClassOf), classinstance relations (rdf:type), property relations and types, and synonyms (owl:sameAs). The property relations are triples: property domain (rdfs:domain), property range (rdfs:range), and property hypernymy-hyponymy relations (rdfs:subPropertyOf). The property types are object (owl:ObjectProperty), data (owl:DatatypeProperty), symmetric (owl:SymmetricProperty), transitive (owl:TransitiveProperty), functional (owl:FunctionalProperty), inverse functional (owl:InverseFunctionalProperty), asymmetric (owl:AsymmetricProperty), reflexive (owl:ReflexiveProperty) and irreflexive (owl:IrreflexiveProperty). To evaluate EWO, we compared it with existing ontologies constructed from English Wikipedia. Thus, we clarified the differences between the existing ontologies and EWO.