Legalo
From STLab
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''dbpedia:All_Star_Band :of dbpedia:Rino_Starr'' | ''dbpedia:All_Star_Band :of dbpedia:Rino_Starr'' | ||
''dbpedia:All_Star_Band rdf:type :Band'' | ''dbpedia:All_Star_Band rdf:type :Band'' | ||
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would generate | would generate | ||
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''label(property) = memberOfBandOf'' | ''label(property) = memberOfBandOf'' | ||
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and | and | ||
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''dbpedia:Felix :memberOfBandOf dbpedia:Ringo_Starr'' | ''dbpedia:Felix :memberOfBandOf dbpedia:Ringo_Starr'' | ||
Revision as of 22:57, 13 June 2014
Legalo
Subgraphs identification algorithm (implemented by the Semantic Web property extractor)
algorithm legalo is input G: a RDF graph from FRED output S: a set of RDF triples expressing semantic relations between named entities recognized in G let E the set of named entities in G let C the set of all named entity pairs combinations including permutations for each named entity e1 in E for each named entity e2 in E if e1 != e2' add <e1, e2'> to C let P a set of tuples <e1, e2, sub-graph> let DFS stand for depth first search for each pair <e1, e2> in C directPaths ← DFS in G retrieving all direct paths between e1 and e2 if directPaths is not empty for each directPath in directPaths add <e1, e2, directPath> to P else for each node of type dul:Event event in G leftSubGraph ← DFS in G for retrieving the shortest direct paths connecting e1 and event rightSubGraph ← DFS in G for finding the shortest direct paths connecting event and e2 if rightSubGraph does not contain agentive roles add <e1, e2, rightSubGraph> to P let S a set of RDF triples for each tuple <e1, e2, sub-graph> in P property ← produce semantic web relation based on sub-graph add RDF triple e1 - property - e2 to S
Producing semantic web relations
Legalo produces a semantic web relation property based on each sub-graph included in P (cf. legalo algorithm) The label of property is generated by concatenating the labels included in the sub-graph according to a number of heuristics derived by incremental empirical observations. These heuristics are continuously evolving. Currently, the main ones are summarizes as follows:
- Given a direct path between e1 and e2, the label of property will be produced by concatenating the arc labels in the path and the more general types' labels of the nodes in the path. See example below:
dbpedia:Felix :memberOf dbpedia:All_Star_Band dbpedia:All_Star_Band :of dbpedia:Rino_Starr dbpedia:All_Star_Band rdf:type :Band would generate label(property) = memberOfBandOf and dbpedia:Felix :memberOfBandOf dbpedia:Ringo_Starr
- a label of a semantic relation is generated by concatenating the properties found in the statements from an event to an object
- some mappings between properties and terms of a semantic relation are performed according to the following criteria
- vnrole:Beneficiary → for
- vnrole:Instrument → with
- vnrole:Destination → to
- vnrole:Topic → about
- while traversing the statements, also the types of subject nodes are taken into account. Namely, given a subject node its most general FRED type is added into the label of a semantic relation
- repetitions of terms into a label of a semantic relation are avoided, i.e. in case of consecutive properties in a sub-graph such as born born only one is used into a semantic relation