Alistair Miles

Category: w3c

Request for Comments — SKOS Reference — W3C Working Draft 25 January 2008

The W3C Semantic Web Deployment Working Group has announced the publication of the SKOS Reference as a W3C First Public Working Draft:

This is a substantial update to and replacement for the previous SKOS Core Vocabulary Specification W3C Working Draft dated 2 November 2005. The publication has been announced in the W3C news, and a request for comments has been sent to various mailing lists.

The abstract from this new specification:

This document defines the Simple Knowledge Organization System (SKOS), a common data model for sharing and linking knowledge organization systems via the Semantic Web.

Many knowledge organization systems, such as thesauri, taxonomies, classification schemes and subject heading systems, share a similar structure, and are used in similar applications. SKOS captures much of this similarity and makes it explicit, to enable data and technology sharing across diverse applications.

The SKOS data model provides a standard, low-cost migration path for porting existing knowledge organization systems to the Semantic Web. SKOS also provides a light weight, intuitive language for developing and sharing new knowledge organization systems. It may be used on its own, or in combination with formal knowledge representation languages such as the Web Ontology language (OWL).

This document is the normative specification of the Simple Knowledge Organization System. It is intended for readers who are involved in the design and implementation of information systems, and who already have a good understanding of Semantic Web technology, especially RDF and OWL.

For an informative guide to using SKOS, see the upcoming SKOS Primer.

Synopsis

Using SKOS, conceptual resources can be identified using URIs, labeled with lexical strings in one or more natural languages, documented with various types of note, linked to each other and organized into informal hierarchies and association networks, aggregated into concept schemes, and mapped to conceptual resources in other schemes. In addition, labels can be related to each other, and conceptual resources can be grouped into labeled and/or ordered collections.

SKOS and RDFa in e-Learning

The W3C’s Semantic Web Deployment Working Group is developing two new technologies which may be relevant to e-learning technology. These are the Simple Knowledge Organisation System (SKOS), and RDFa.

SKOS is a lightweight language for representing intuitive, semi-formal conceptual structures. So, for example, the figure below (taken from the SKOS Core Guide) depicts concepts with intuitive hierarchical and associative relationships to other concepts, and with preferred and alternative labels in one (or more) languages — these are the kinds of structures that can be expressed using SKOS. Once expressed in this form, conceptual structures can easily be published on the Web, shared between applications, linked/mapped to other conceptual structures and so on. Typically, these conceptual structures are used as tools for navigating around complex or unfamiliar subject areas, for retrieving information across languages, and for bringing together related information from different sources.

RDFa is a language for embedding richly structured data and metadata within Web pages. This allows a Web page to expose much of its underlying meaning to applications, enabling a range of new functionalities within Web clients, exchanging data between Web sites, services, and the users’ desktop applications. For example, a Web page about a new music album can use RDFa to embed structured data expressing facts about that album, such as the track listing, artist, links to sample media files etc. A Web browser with a suitable plugin or extension can use this data to offer new functions to the user, such as download the tracklisting with available samples to my music library, or compare prices from online vendors.

Both of these technologies are on the W3C Recommendation track, and are scheduled for completion in April 2008.

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New SKOS Web Site

I should have mentioned earlier … the SWDWG rolled out a new and improved SKOS web site a couple of weeks ago. We reorganised the web site a bit to make it easier to navigate, and also hopefully to provide a higher profile for the community areas such as the data zone, the tool shed and the mailing list.