Several members of the Working Group gathered at the Institute of Informatics and Technology, part of NCSR "Demokritos,"
for this 2 day face to face meeting and were very pleased to welcome guests Irini Fundulaki of FORTH, Giorgos Stoilos of NTUA and HP's Jeremy Carroll who attended in his capacity as the OWL 1.1 WG
's liaison to POWDER. Substantially as a result of Jeremy's input at the meeting and beforehand on both the GRDDL
mailing lists (with significant input from David Booth) the meeting has agreed a new representation of Description Resources. This will be written up in new drafts of the POWDER technical documents as soon as possible, with publication expected within two weeks or so.
In brief, a POWDER document will be written in XML with a root element in the POWDER namespace. The format of such a document will be similar, but not identical, to that already proposed. These documents encode the operational semantics of POWDER – attribution, scope and description – and may be processed in a non-semantic environment. Critically, however, a GRDDL transform associated with the POWDER namespace, when executed, will create an RDF/XML instance with formal semantics that underpin and effectively define the operational semantics of POWDER.
Two semantic extensions will be defined. The first will relate a string of the form "http://example.org" to the superficially similar URI <http://example.org>. The second defines the semantics of the white space-separated lists of strings envisaged in the Grouping of Resources document so that they can be interpreted as components of a URI. Thus, the following example can take on the intended meaning of the set of URIs that have a host component with a first and second level domain of example.org or example.com:
More details will be presented in the technical documents, however, the general approach is now agreed. It meets the difficult challenge of creating a system that can work in the day to day, non-semantic web scenarios envisaged in the use cases whilst allowing the data to be processed within a semantic web environment. Several other issues were discussed, such as potential implementations, the test suite, exit criteria for Candidate Recommendation and so on, but the headline from the meeting is clear. After a period in which the group's fundamental approach has been questioned (and was very nearly jettisoned), there is a feeling that the work is back on track. The group records its thanks to NCSR for hosting the meeting, welcomes the interest from its guests, and records its gratitude to Jeremy Carroll for his insight and clear explanations.