Sharing Ontologies Over the Web

With Zdenek Zdrahal i've become interested in sharing ontologies over the web. The work is focused around a collaborative ontology browsing and editing tool call WebOnto and a tool for the synchronous and asynchronous discussion about models call Tadzebao. You can now use WebOnto from here.

The overall design goal for Tadzebao was to support both asynchronous and synchronous discussions on ontologies. Asynchronous discussions are necessary because an ontology design team or community may be spread over large time zones. Synchronous discussions are useful a) when a dialogue is composed of many small utterances, b) when there is time pressure, or c) to give users a sense of belonging to a team or community.

Because design dialogues are mainly about the artefact under construction it was important to allow knowledge engineers to refer directly to ontologies in their messages. This meant that Tadzebao had to integrate tools, such as text editors and drawing tools, for expressing general ideas with tools for manipulating ontologies.

Before describing the system itself a brief explanation of the name is necessary. Tadzebao, which literally means "Big Character Poster", is the Chinese word for the type of poster used to support political debate during the Cultural Revolution. During the Cultural Revolution a political argument or ideology would be expressed through the placement of a poster (a tadzebao). Rebuttals to or comments on the initial argument would be expressed by additional posters (tadzebaos) on top of or around the original poster.

Tadzebao uses an extension of this metaphor for guiding knowledge engineers around ongoing dialogues on ontologies. Within Tadzebao, dialogues are centred around a notepad which contains a series of pages. Each notepad page can contain a mixture of text, GIF images, hand drawn sketches and ontology components represented in OCML (Motta, 1998). Dialogues can be browsed by clicking on the bottom right corner of a notepad. The figure below shows six notepads each containing a design dialogue.

Figure 1. A screen snapshot of Tadzebao in use.

WebOnto was designed to support the collaborative browsing, creation and editing of ontologies without suffering from the interface problems described in the previous section. In particular, WebOnto was designed to provide a direct manipulation interface displaying ontological expressions using a rich medium. WebOnto was aimed to be easy-to-use, yet have facilities for scaling up to large ontologies. Finally, WebOnto was designed to complement the ontology discussion tool Tadzebao. The figure below shows an ontology engineer editing the KMI Planet Ontology. In the figure the class hierarchy for the class kmi-event is shown. The ontology engineer is currently creating a new instance of the class awarding-body using an automatically created form.

Figure 2. A screen snapshot of WebOnto in use.

For more information about our knowledge modelling work please check out our knowledge modelling pages. We have a couple of gzipped postscript papers, describing part of the work, which you can download: 

Knowledge Media Institute
The Open University, U.K.