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Hi All, I recently attended a conference on schemas and ontologies. Here is a summary of the main points. Ed Schemas and Ontologies: Building a Semantic Infrastructure for the GRID and Digital Libraries Date 16 May 2003-05-22, Venue e-Science Institute, 15 South College Street. The Schemas and Ontologies seminar was organised by UKOLN and the e-science Core Programme. The aim of the event was to help bring GRID and digital library implementers together to consider approaches to developing, expressing and sharing schemas and ontologies. The event consisted of speakers explaining some theoretical aspects of a semantic infrastructure and practical examples of ontology and schema use in medicine, biology and educational metadata. There were also discussion breakout groups looking at: Barriers to sharing ontologies; Software tools and shared services; The process of building a community-led ontology. Formally speaking an Ontology “defines terms used to describe and represent an area of knowledge” (Ref 1). One way of thinking about an ontology is to consider it as: a collection of objects that are linked together in certain ways. This means that the word ontology can define a range of structures from simple taxonomies to metadata schemas, to logical theories. A very good introduction to ontologies can be found at (Ref 2). This uses a wine ontology as an example Ontologies can be described using web ontology languages. The most recent one is OWL (Ref 8) and it has been formed from DAML and OIL. A Practical example of ontology use (in the field of medicine) was given by Dr Jeremy Rogers from the University of Manchester He explained how in the past medical conditions had been described by long descriptions. Current systems use combinations of words to form concepts. So one might form a concept by selecting several words from several lists. This sort of information is easier for machines to read than lengthy descriptions. The cost of building the terms and rules is large and there can be problems with interpretation of results. Professor Carole Goble, University of Manchester, talked about the use of ontologies for carrying semantics in the context of The Grid with reference to projects myGrid(Ref 3) and Geodise (Ref 4). Issues discussed included looking at tools and services for supporting biological sciences and ontologies as a means of integrating and exchanging resources. It is also important to make sure communities are aware of other practices in order to facilitate resource sharing and reuse. Registries, which store details of schemas and ontologies, can encourage sharing and reuse. Rachel Heery of UKOLN, talked about the need to use registries and promote publishing and sharing schemas. The idea is to manage schemas in such a way that that reuse and sharing of metadata is encouraged but to allow for extensibility and meet local requirements. This was supplemented by a practical demonstration of the MEG Registry by Pete Johnston of UKOLN. This Registry allows users to register educational metadata schemas and elements and make use of existing schemas, elements and vocabularies. For further details see (Ref 7) Doug Tudhope of the University of Glamorgan gave a talk on Knowledge Organisation Systems (KOS). This covered a review of current Digital Library work on KOS and research into connections between ontologies and the semantic web. The two main sources of information for the talk were NKOS: Networked Knowledge Organisation Systems/Services (Ref 5)and SEMKOS FP6 IP Proposal (Ref 6) NKOS is devoted to the discussion of the functional and data model for enabling knowledge organization systems (KOS), such as classification systems, thesauri, gazetteers, and ontologies, as networked interactive information services to support the description and retrieval of diverse information resources through the Internet. SEMKOS is involved in research into connections between KOS and The Semantic Web. DISCUSSION GROUPS The discussion groups, which were set up, covered many of the issues that are important to establishing and maintaining ontologies. It is interesting to note that almost all the points mentioned apply to metadata schema implementation as well. Thee are a lot of barriers to sharing ontologies: · Cost of creation and maintenance is very high. The medical ontology discussed by Jeremy Rogers contains 20,000 concepts and took 15 work-years to create. · The technology is immature and there are not many tools available. · People need to be aware of the costs and benefits about using and sharing ontologies. · It is difficult to ensure quality control. Several suggestions about how to encourage uptake were given · Ontologies should be free if used for non-profit purposes · Further tools are necessary to support ontology building and browsing · Clear applications and demonstrations need to be given to promote use. · Establishing ontolgies requires a lot of money, time and effort. Professor Goble and Dr Rogers gave examples of successful ontologies and how they were set up. For the medical application, the project was well funded for set up and maintenance. For the genetics ontology, it started off with a small group of enthusiasts that gradually became more established and received funding. · It is important to be systematic when creating an ontology. Adding new terms can either be done by group decision or by having one person in charge who decides what should go in (referred to as the “benign dictator” method). Both methods have benefits and problems. · It is important to make sure that end users will be able to make practical use of the ontologies and that user interfaces are not too complicated. REFERENCES 1) Quote from Jeff Heflin, Web Ontology Language Use Cases and Requirements, W3C, February 2003, http://www.w3.org/TR/webont-reg/ 2) http://www.ksl.stanford.edu/people/dlm/papers/ontology-tutorial-noy-mcguinness-abstract.html. 3) http:/www.mygrid.org.uk 4) http://www.geodise.org 5) http://nkos.slis.kent.edu/ 6) http://www.lub.lu.se/SEMKOS/ 7) http://www.ukoln.ac.uk/metadata/education/regproj/. 8) http://www.w3.org/TR/2002/WD-owl-guide-20021104/