I'm getting a pretty good taste of why the semantic web hasn't exactly taken off today. I'm trying to use an OWL ontology produced by one of the world's leading universities in semantic web research to classify a couple RDF instances..
This would seem to be a straightforward task neh? Simply add the ontology to a reasoner, feed it the RDF containing the instances, and have a look at any inferred types it identifies.. Right?
Wrong!
A) The ontology utilizes qualified cardinality restrictions..
So, the current version of Jena (that I have) can't really handle it because this is OWL1.1
Pellet accepts these nasties (is mostly owl1.1. compliant I think) but ran for more than 20 minutes trying to classify it before I gave it up (on relatively new MacBook with 2gb ram)
Pellet has now been running for 20 minutes on our IBM P570..
and this is just an 80 class ontology!!!
B) To create the RDF instances that fit into the ontology framework, I had to either create them as RDF types of a qualified cardinality restriction (which Jena couldn't handle in OWL mode) or add multiple object property assertions that are apparently producing something invalid..
(from command line Pellet)
WARN [main] (KnowledgeBase.java:898) - Inconsistent ontology. Reason: Individual http://www.owl-ontologies.com/unnamed.owl#Afu3g10970 has more than 2 values for property http://www.owl-ontologies.com/unnamed.owl#containsDomain violating the cardinality restriction
I'm starting to feel like an idiot for a variety of reasons. I'm not used to having so much trouble making things like this work - its kind of my job.. and if its this difficult and time-consuming for some one who actually cares about it, how is the technology ever going to penetrate the great majority of the world that simply wants something to work? Perhaps I've been foolish in advocating the W3C's ideas for the semantic web.
Hopefully better news later this week
Showing posts with label Pellet. Show all posts
Showing posts with label Pellet. Show all posts
Thursday, March 15, 2007
semantic web suffering
Posted by Benjamin Good at 5:49 PM 3 comments
Labels: frustration, Jena, Pellet, semantic web
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