It's quite exciting to see various initiatives within UK government starting to make use of Semantic Web technologies, and particularly of RDFa. At the recent OKCon conference, I heard Jeni Tennison talk about her work on using RDFa in the London Gazette. Yesterday, Mark Birbeck published a post outlining some of his work with the Central Office of Information.
The example Mark focuses on is that of a job vacancy, where RDFa is used to provide descriptions of various related resources: the vacancy, the job for which the vacancy is available, a person to contact, and so on. Mark provides an example of a little display app built on the Yahoo SearchMonkey platform which processes this data.
As a a footnote (a somewhat lengthy one, now that I've written it!), I'd just draw attention to Mark's description of developing what he calls an RDF "argot" for constructing such descriptions:
The first vocabularies -- or argots -- that I defined were for job vacancies, but in order to make the terminology usable in other situations, I broke out argots for replying to the vacancy, the specification of contact details, location information, and so on.
An argot doesn't necessarily involve the creation of new terms, and in fact most of the argots use terms from Dublin Core, FOAF and vCard. So although new terms have been created if they are needed, the main idea behind an argot is to collect together terms from various vocabularies that suit a particular purpose.
I was struck by some of the parallels between this and DCMI's descriptions of developing what it calls an "DC application profile" - with the caveat that DCMI typically talks in terms of the DCMI Abstract Model rather than directly of the RDF model. e.g. the Singapore Framework notes:
In a Dublin Core Application Profile, the terms referenced are, as one would expect, terms of the type described by the DCMI Abstract Model, i.e. a DCAP describes, for some class of metadata descriptions, which properties are referenced in statements and how the use of those properties may be constrained by, for example, specifying the use of vocabulary encoding schemes and syntax encoding schemes. The DC notion of the application profile imposes no limitations on whether those properties or encoding schemes are defined and managed by DCMI or by some other agency
And in the draft Guidelines for Dublin Core Application Profiles:
the entities in the domain model -- whether Book and Author, Manifestation and Copy, or just a generic Resource -- are types of things to be described in our metadata. The next step is to choose properties for describing these things. For example, a book has a title and author, and a person has a name; title, author, and name are properties.
The next step, then, is to scan available RDF vocabularies to see whether the properties needed already exist. DCMI Metadata Terms is a good source of properties for describing intellectual resources like documents and web pages; the "Friend of a Friend" vocabulary has useful properties for describing people. If the properties one needs are not already available, it is possible to declare one's own
And indeed the Job Vacancy argot which Mark points to would, I think, probably be fairly recognisable to those familiar with the DCAP notion: compare, for example, with the case of the Scholarly Works Application Profile. The differences are that (I think) an "argot" focuses on the description of a single resource type, and I don't think it goes as far as a formal description of structural constraints in quite the same way DCMI's Description Set Profile model does.