Difference between revisions of "Lab: OWL 1"
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Revision as of 18:14, 4 March 2020
Lab 7: RDFS Plus / Basic OWL
Basic OWL ontology programming with RDFlib and owlrl. WebVOWL visualisation.
- OWL (sameAs, equivalentClass, equivalentProperty, differentFrom, disjointWith, inverseOf)
- OntModel (createClass, createIndividual, createObjectProperty, CreateDatatypeProperty, createAllDifferent, createSymmetricProperty, createTransitiveProperty, createInverseFunctionalProperty),
- Model (createList, write),
- OntClass, Individual, DatatypeProperty, ObjectProperty
Note that the OntModel interface extends InfModel and Model.
Extend the RDF and RDFS graphs from earlier to account for the following situation:
Consider the following situtations: Cade and Emma are two different persons. All the countries mentioned above are different. The country USA above is the same as the DBpedia resource http://dbpedia.org/resource/United_States (dbr:United_States) and the GeoNames resource http://sws.geonames.org/6252001/ (gn:6252001). The person class (the RDF type the Cade and Emma resources) in your graph is the same as FOAF's, schema.org's and AKT's person classes (they are http://xmlns.com/foaf/0.1/Person, http://schema.org/Person, and http://www.aktors.org/ontology/portal#Person, respectively. Nothing can be any two of a person, a university, or a city at the same time. The property you have used in your RDF/RDFS graph to represent that 94709 is the US zip code of Berkeley, California in US is a subproperty of VCard's postal code-property (http://www.w3.org/2006/vcard/ns#postal-code). No two US cities can have the same postal code. The property you have used for Emma living in Valencia is the same property as FOAF's based near-property (http://xmlns.com/foaf/0.1/based_near), and it is the inverse of DBpedia's hometown property (http://dbpedia.org/ontology/hometown, dbo:hometown). (This is not completely precise: but "hometown" is perhaps the inverse of a subproperty of "based near".)
Create a graph from this scenario using OWL triples in RDFlib.. If you can, try to build on your example from labs 2 and 3!
Look through the predicates(properties) above and make new triples for each one that describing them as any of the following: a reflexive , irreflexive, symmetric, asymmetric, or a transitive property.
Write the ontology to a TURTLE file, and try to visualise it using http://visualdataweb.de/webvowl/ . WebVOWL is oriented towards visualising classes and their properties, so the individuals may not show.
Use OntModel.writeAll() to write out the whole ontology, including OWL's built-in axioms (note that sending it to WebVOWL may not work.) Add a reasoner to your OntModel, for example ModelFactory.createOntology(OntModelSpec.OWL_MEM_RULE_INF), and writeAll() again. Can you spot any inferences?