From harry.chen at umbc.edu  Wed Jun 16 14:59:18 2004
From: harry.chen at umbc.edu (Harry Chen)
Date: Wed Jun 16 15:00:03 2004
Subject: [CoBrA-users] Re: Using the Temporal Reasoner with OWL
In-Reply-To: <011f01c453d4$6ae967b0$0121020a@IHMC>
References: <011f01c453d4$6ae967b0$0121020a@IHMC>
Message-ID: <A6A43980-BFCF-11D8-96A4-000A957913E0@umbc.edu>

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On Jun 16, 2004, at 3:02 PM, Larry Bunch wrote:

> I'm particularly interested in using the temporal reasoner in Jena, so
> please point me to the Java API you mentioned.

At the moment, there is no binary release. You have to fetch source 
from the CVS compile time.

http://projects.semwebcentral.org/scm/?group_id=22

Required Java library:
- - Jena 1.2

Following the Jena reasoner API convention, I created two classes for 
instantiating a temporal reasoner (see the "src" directory in CVS).

package: soupa.reasoner.time

SOUPATimeReasoner.java
SOUPATimeReasonerFactory.java

A test example code can be found in

package: edu.umbc.cobra.test

TestSOUPAReasoner.java

test data: tests/time-t1.owl

Here is a bit more detail behind the implementation:

The rules are implemented based on the SOUPA time ontology. This 
ontology is about the same as the DAML time and the time entry 
sub-ontology.

http://pervasive.semanticweb.org/ont/dev/time

A Java class representation of this ontology is

edu.umbc.cobra.vocabulary.soupa.Time

With this class, in your code, you can reference the defined time 
ontology terms as static Java objects. This is similar to the standard 
OWL/RDF vocabulary classes provided by Jena.

A typical usage:

1) create a Model (a simple RDF model, not OWL)

2) load RDF statements into the Model (statements that are expressed 
using the SOUPA time ontology)

3) call SOUPATimeReasonerFactory to create a SOUPATimeReasoner

4) create an InfModel by calling

InfModel infModel = ModelFactory.createInfModel(reasoner,dataModel);

5) query the infModel.


NOTE: be aware that if you use an OWL inference model (i.e., a model 
that already has an OWL reasoner attached) in conjunction with the 
temporal inference model, you may experience java runtime exceptions 
(e.g., out of memory). as far as I know, this is a performance issue 
with the Jena's OWL reaosner. For this reason, I often build temporal 
inference model based on a plain RDF model.

Let me know if you have any questions.

- - Harry

- --
Harry Chen <> eBiquity Research Group <> Dept. of CSEE UMBC
mailto:harry.chen@umbc.edu <> http://umbc.edu/people/hchen4
<>  8303 775C F587 8F91 673B  000A C396 A7F5 C12B D936   <>
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