HyLAR-Reasoner

An OWL 2 RL incremental reasoner for the Web.

Description

HyLAR-Reasoner is an OWL 2 RL reasoner that uses JSW and OWLReasoner as a triplestore and provides an additional incremental reasoning engine. The framework implementation of HyLAR can be tested online at http://dataconf.liris.cnrs.fr/hylar/

NB: Performances have been drastically improved since v. 1.5

Supported OWL constructs and inferences

HyLAR currently supports partial OWL 2 constructs (ObjectSomeValuesFrom, DataSomeValuesFrom, InverseObjectProperties, ObjectPropertyRange, ObjectPropertyDomain and DataPropertyRange). It also provides the following inferences, based on the semantics presented in https://www.w3.org/TR/owl2-profiles/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules :

(?c1, http://www.w3.org/2000/01/rdf-schema#subClassOf, ?c2) ^ (?c2, http://www.w3.org/2000/01/rdf-schema#subClassOf, ?c3) -> (?c1, http://www.w3.org/2000/01/rdf-schema#subClassOf, ?c3)

(?c1, http://www.w3.org/2000/01/rdf-schema#subClassOf, ?c2) ^ (?x, http://www.w3.org/1999/02/22-rdf-syntax-ns#type, ?c1) -> (?x, http://www.w3.org/1999/02/22-rdf-syntax-ns#type, ?c2)

(?p1, http://www.w3.org/2000/01/rdf-schema#subPropertyOf, ?p2) ^ (?p2, http://www.w3.org/2000/01/rdf-schema#subPropertyOf, ?p3) -> (?p1, http://www.w3.org/2000/01/rdf-schema#subClassOf, ?p3)

(?p1, http://www.w3.org/2000/01/rdf-schema#subPropertyOf, ?p2) ^ (?x, ?p1, ?y) -> (?x, ?p2, ?y)

(?x, ?p, ?y) ^ (?p, http://www.w3.org/1999/02/22-rdf-syntax-ns#type, http://www.w3.org/2002/07/owl#TransitiveProperty) ^ (?y, ?p, ?z) -> (?x, ?p, ?z)

(?p1, http://www.w3.org/2002/07/owl#inverseOf, ?p2) ^ (?x, ?p1, ?y) -> (?y, ?p2, ?x)

(?p1, http://www.w3.org/2002/07/owl#inverseOf, ?p2) ^ (?x, ?p2, ?y) -> (?y, ?p1, ?x)

(?c1, http://www.w3.org/2002/07/owl#equivalentClass, ?c2) ^ (?x, http://www.w3.org/1999/02/22-rdf-syntax-ns#type, ?c1) -> (?x, http://www.w3.org/1999/02/22-rdf-syntax-ns#type, ?c2)

(?c1, http://www.w3.org/2002/07/owl#equivalentClass, ?c2) ^ (?x, http://www.w3.org/1999/02/22-rdf-syntax-ns#type, ?c2) -> (?x, http://www.w3.org/1999/02/22-rdf-syntax-ns#type, ?c1)

(?p1, http://www.w3.org/2002/07/owl#equivalentProperty, ?p2) ^ (?x, ?p1, y) -> (?x, ?p2, ?y)

(?p1, http://www.w3.org/2002/07/owl#equivalentProperty, ?p2) ^ (?x, ?p2, y) -> (?x, ?p1, ?y)

(?s1, http://www.w3.org/2002/07/owl#sameAs, ?s2) ^ (?s1, ?p, ?o) -> (?s2, ?p, ?o)

(?p1, http://www.w3.org/2002/07/owl#sameAs, ?p2) ^ (?s, ?p1, ?o) -> (?s, ?p2, ?o)

(?o1, http://www.w3.org/2002/07/owl#sameAs, ?o2) ^ (?s, ?p, ?o1) -> (?s, ?p, ?o2)

(?x, http://www.w3.org/2002/07/owl#sameAs, ?y) ^ (?y, http://www.w3.org/2002/07/owl#sameAs, ?z) -> (?x, http://www.w3.org/2002/07/owl#sameAs, ?z)

This list of rules can be restricted by editing the file (root)/hylar/core/OWL2RL.js. At classification time, inferences are performed in the default graph.

Getting started

Use HyLAR's reasoner module locally

I. Install locally

npm install --save hylar

II. Import HyLAR, then classify your ontology and query it

(currently accepts OWL 2 XML serialization only)

var Hylar = require('hylar');
var classifiedOntology, queryResults;

classifiedOntology = Hylar.classify('./fipa.owl'));

queryResults = Hylar.query('PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> ' +
                            'PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> ' +
                            'SELECT ?a ?b { ?a rdfs:subClassOf ?b }');

Use HyLAR as a server

I. Install HyLAR globally

npm install -g hylar

II. Use CLI to run HyLAR as a server

hylar --port 3000 -od /usr/local/share/ontologies/

--port <port_number> or -p <port_number> is optional. HyLAR runs at port 3000 by default.

--ontology-directory </your/base/ontology/directory/> or -od </your/base/ontology/directory/> is also optional. This parameter specifies the directory in which ontologies are located, in order to classify them. By default, HyLAR uses its module path, i.e. {path_to_hylar}/server/ontologies/.

It then outputs:

[HyLAR] Setting up routes...
[HyLAR] Done.
[HyLAR] Exposing server to port 3000...
[HyLAR] Done.
[HyLAR] HyLAR is running.

III. Request HyLAR as follows

(GET) /classify

Parameters filename (the absolute path of the ontology file to be processed) Parses and classify an ontology (OWL 2 XML serialization). Supports Classes, ObjectProperties and DatatypeProperties. This step has to be done before sending any SPARQL query (but only once, as the reasoner instance is kept in-memory).

(GET) /query

Parameters query (the SPARQL query string) Being a GET request parameter, the query must be urlencoded accordingly.