Semantic Web Best Practices and Deployment Working Group
Vocabulary Management Task Force (VM)

This page: Working Drafts | Editor's Drafts | Objectives | Membership

Nearby: SWBPD Home

This task force of the Semantic Web Best Practices and Deployment WG is in support of the group's chartered aim of supporting the deployment in RDF/OWL of structured vocabularies.

Membership

• Thomas Baker <tbaker@tbaker.de> (Goettingen State and University Library), Coordinator
• Dan Brickley (W3C)
• Libby Miller (Asemantics)
• Alistair Miles (CCL)
• Ralph Swick (W3C)

Working Drafts

Editor's Drafts

The following documents are Editor's Drafts, prepared for discussion by SWBPD-WG prior to formal publication:

• Best Practice Recipes for Publishing RDF Vocabularies (aka "Apache configuration cookbook"), Editor's Draft (latest version), Alistair Miles, editor.
• Managing a Vocabulary for the Semantic Web - Best Practice, Wiki draft (work suspended to work on the cookbook).

Objectives

Short-term objectives

• To define (in a Note or Editor's Draft) a set of good-practice "recipes" for configuring an Apache server for content negotiation such that:
  • If a person tries to dereference the URI of a class or property (i.e. via a Web browser), they end up at the relevant bit of human-readable documentation.
  • If a machine tries to dereference the URI of a class or property, they end up with a serialisation of a set of RDF statements describing that class or property, with a provenance that allows differentiation of different 'versions' of an RDF schema/ontology.
  • The dereferencing solution complies with TAG resolution on httpRange-14.
• To wrap those recipes in enough context to make them usable by vocabulary maintainers to provide documentation and schemas for their vocabularies.

Long-term issues

• URIs based on PURL.ORG. DC, RSS, and vocab.org use URIs based on purl.org, which currently responds to GET requests with 302 (Temporarily Moved). The TAG decision on httpRange-14 requires 303 (Redirect). This was discussed in a mailing list thread. In July, Dan asked TAG whether a 302 response on a purl.org URI would be acceptable. As of November, Alistair has included purl.org scenarios in the draft cookbook.
• Awareness of multiple representations. If content negotiation is handled in the background and alternative representations of a vocabulary in RDF or HTML are served up to a user seemingly automatically -- on the basis of Apache configurations -- how would an interested user know which other representations were available?
Should there be some way for a user to learn about other representations (e.g., via cross-references or an overview page)?
• Notion of a "Definitive RDF description". Peter Patel-Schneider has questioned the focus on one "definitive RDF description" for each RDFS/OWL class, property, or individual -- as opposed to an RDFS description, an OWL description, or multiple "definitive" descriptions.
• Provenance and URIs. Provenance is supported by using the final URI from the chain of redirects as the name of the graph; different URIs represent different versions of a vocabulary. Tom has noted that, in practice, "date-stamped" URIs are often used and suggests we explicitly acknowledge both that URI strings are in theory opaque and unparsable and that there are de-facto social conventions for using date stamps or version numbers.
• rdfs:isDefinedBy. Clarifying the dereferencing options provides an opportunity to clarify good practice for the use of rdfs:isDefinedBy. Instead of relying on URI string manipulation in an attempt to heuristically locate a namespace, namespaces should be declared with rdfs:isDefinedBy.
• Change management for RDFS/OWL ontologies.
There was discussion on whether this should more properly be called "change management" or even "version documentation". Current DCMI practice has been described. The emerging consensus is that it is best to version the description of a property (i.e., the RDF statements about it), not the property itself. I.e. each 'version' is a named graph; provenance information can then be used to distinguish between different descriptions of a property. Alistair notes that the issues of versioning and change management are coming to the fore in the OWL community.
• Part 1. Naming
• Part 2. Metadata
• Principles of Good Practice (see Wiki draft).
• Identify Terms with URIs.
• Articulate and publish maintenance policies for the Terms and their URIs.
• Identify the historical version of a Vocabulary or its Terms.
• Provide natural-language documentation about the Terms.
• Declare the Terms using a formal, machine-processable schema language.

See also

• 2005-11-22, Vocabulary Management Task Force progress report.

Dependencies

• SWBP Thesaurus Task Force (THES)
• TAG decision on httpRange-14
• SWBP response to TAG decision on httpRange-14

Last updated $Date: 2006/03/07 10:55:51 $ by $Author: tbaker3 $

$Id $