Geospatial Semantic Web Blog

The ability to represent time and temporal relations is an important aspect of the Semantic Web. W3C recently published a new working draft on Time Ontology in OWL. This work is an updated version of the OWL-Time ontology developed by Jerry Hobbs and Feng Pan.

Before the standardization of the OWL language, Jerry and Feng also worked on a version of the ontology in DAML. Their previous works on time ontologies can be found at Feng’s OWL-Time website.

In the RDF and OWL world, there are at least two different ways to represent time. One way is to use XSD datatypes (e.g., xsd:datetime), and the other is to use OWL-Time. Sometimes people ask me which approach is better for representing time in their applications.

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Prof. Tim Finin posted a video of our first Semantic Web application: ITTalks. It’s a talk announcement system that publishes web contents in both human and machine readable format.

This system was developed under the DARPA DAML program. Part of the existing Web Ontology Language OWL is based on an ontology language (i.e., DAML+OIL) developed under this program. In 2000, semantic web research was mostly focused on how to publish machine readable web contents and annotate web information using shared ontological vocabularies.

If you watch the video and compare the ITTalks system with some recent Semantic Web applications, you see obvious difference in their research focus and feature capabilities.

From my personal perspective, since I have worked on the ITTalks project and still in the Semantic Web field, I think Semantic Web research has evolved from how to define ontologies to how to reasoning with ontologies, from how to publish machine readable contents to how to integrated machine readable contents and their semantics, and from how to build proof-of-concept systems to how to develop commercial quality systems.

I’m looking forward to another five years of Semantic Web development.