Simple Knowledge Organization System

SKOS is part of the Semantic Web family of standards built upon RDF and RDFS, and its main objective is to enable easy publication and use of such vocabularies as linked data.

The most direct ancestor to SKOS was the RDF Thesaurus work undertaken in the second phase of the EU DESIRE project [1][citation needed].

Motivated by the need to improve the user interface and usability of multi-service browsing and searching,[2] a basic RDF vocabulary for Thesauri was produced.

SKOS as a distinct initiative began in the SWAD-Europe project, bringing together partners from both DESIRE, SOSIG (ILRT) and LIMBER (CCLRC) who had worked with earlier versions of the schema.

[7] Following the termination of SWAD-Europe, SKOS effort was supported by the W3C Semantic Web Activity[8] in the framework of the Best Practice and Deployment Working Group.

[9] During this period, focus was put both on consolidation of SKOS Core, and development of practical guidelines for porting and publishing thesauri for the Semantic Web.

The main issues to solve were determining its precise scope of use, and its articulation with other RDF languages and standards used in libraries (such as Dublin Core).

[15][16] On August 18, 2009, W3C released the new standard that builds a bridge between the world of knowledge organization systems – including thesauri, classifications, subject headings, taxonomies, and folksonomies – and the linked data community, bringing benefits to both.

Libraries, museums, newspapers, government portals, enterprises, social networking applications, and other communities that manage large collections of books, historical artifacts, news reports, business glossaries, blog entries, and other items can now use SKOS[17] to leverage the power of linked data.

In addition to the reference itself, the SKOS Primer (a W3C Working Group Note) summarizes the Simple Knowledge Organization System.

The SKOS[18] defines the classes and properties sufficient to represent the common features found in a standard thesaurus.

The principal element categories of SKOS are concepts, labels, notations, documentation, semantic relations, mapping properties, and collections.

Concepts are the units of thought—ideas, meanings, or objects and events (instances or categories)—which underlie many knowledge organization systems.

In SKOS, a Concept (based on the OWL Class) is used to represent items in a knowledge organization system (terms, ideas, meanings, etc.)

The concepts relatedMatch, broadMatch, and narrowMatch are a convenience, with the same meaning as the semantic properties related, broader, and narrower.

[42] SKOS is intended to provide a way to make a legacy of concept schemes available to Semantic Web applications, simpler than the more complex ontology language, OWL.

OWL is intended to express complex conceptual structures, which can be used to generate rich metadata and support inference tools.