Build an OWL file with JENA

Question

My work requires a construction of ontologies modules. For this I need to construct owl files to contain those ontologies. My input is an xml file with parsed and splitted sentences.

<Subject> A tumor </Subject> 
<Verb> is </Verb> 
<Object> an abnormal growth </Object> 
</sentence> 
<sentence> 
<Subject> A kidney tumor </Subject> 
<Verb> is </Verb> 
<Object> an abnormal growth </Object> 

What I need to do now is:

• convert "subject" and "object" into OntClass
• convert "verb" into a transitive property between "obj" and "sub"

I am new on the ontology domain, may be those are basic questions, but I am struggling with the creation of those files, and especially with the transitive property.

Any help is welcome.

Answer 1

To create an OntClass , you simply need to call OntModel.createClass( uri ) . Of course, that then leaves the question of which uri you should use. You'll need a namespace, something of the form http://yourcompany.com/ontology/diagnosis# ; ideally this namespace will correspond to a web address where your ontology document can be retrieved.

Then you'll need an algorithm for converting a phrase like 'A tumor' into a class name. This could be quite simple:

• remove prefixes such as definite and indefinite articles (a, an, the)
• remove spaces and use CamelCase to denote word boundaries

Then the uri will be the concatenation of the namespace and the converted name.

Creating transitive properties is also straightforward ( OntModel.createTransitiveProperty() ), but in the sample that you show, it appears that you're actually talking about the sub-class relationship between classes. If it is always true that all ns:KidneyTumor instances are also in the set of ns:AbnormalGrowth instances, then your <Verb>is</Verb> corresponds to the existing RDF property rdfs:subClassOf . Of course, if that relationship is more subtle (eg may be conditionally or probabilistically true), then you'll need a different relationship with your particular semantics.

As for reading the XML file, there are many tutorials on the web or questions on Stackoverflow to help with that.