There is a pressing need to integrate ontologies.

I base this observation on purely anecdoctal evidence. For example, I continue to notice papers on this topic at a number of scientific conferences. Of course this is a welcome and expected outcome, as the need arises for inter-, intra- and extra-disciplinary ontology integration as various scientific disciplines develop their own ontologies.

In the bigger scheme of things, this is a also very positive sign that the promise of the Semantic Web is starting to be realized, as ontologies comprise a key component.

Why is this happening? Now? I believe it’s because it’s becoming easier to develop ontologies.

The first ontologies were likely developed manually (i.e., hand coded) from the top down. NASA’s SWEET is a good example of such a formal ontology. Today, formal ontologies are developed with the aid of editors like Protege or SWOOP.

In recent times, however, there’s been emphasis on developing ontologies from the bottom up.

The development of such informal ontologies (or folksonomies) is also being aided by leading-edge technologies:

• Computer-Assisted Development of Ontologies (CADO) – Easy-to-use end user tools are being developed to directly and proactively engage scientists in the point-and-click, drag-and-drop process of developing ontologies. (Note: I purposely used “CAD” in the acronym here to resonate with “Computer Assisted Drafting” familiar to those with experience in, for example, industrial manufacturing.)
• Automated Ontology Extractors (AOEs) – Technologies like GRDDL (Gleaning Resource Descriptions from Dialiects of Languages) are being used to automate the extraction of relationships from XML-based representations. The relationships are captured in the Resource Description Format (RDF). In turn, RDF can be recast in OWL (Web Ontology Language), resulting in an automatically generated ontology. This is an area that particularly fascinates me, and I’ve written about it elsewhere in some detail. One of my current research projects aims to integrate annotations encapsulated via XPointer into these automatically generated knowledge representations. This is an endeavor, I’m finding out, that bears much in common with the thrust of this post on integrating ontologies.

When I saw Web inventor Sir Tim Berners-Lee deliver a keynote at Bio-IT World in May 2005, it was quite clear that he was very excited about GRDDL. Why? He sees exemplars like GRDDL as vehicles for enabling ontology creation, and therefore ultimately realizing his original vision for a next-generation Web, i.e., a Semantic Web.

Because evangelism is one of the key values that Berners-Lee needs to continue to deliver on, it must be gratifying for him to see his efforts paying off in the current example of ontology development. In other words, we’re in the throes of shifting from a need to emphasize ontology development, to a need to emphasize ontology integration. There are clearly many challenges in integrating ontologies. Considerable emphasis is, and needs to continue to be, placed on this important topic. However, there’s little question that the ultimate outcome of a much-more semantically enabled Web will be worth the investment.