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The Simple Knowledge Organization System (SKOS), in the Context of Semantic Web Deployment

This past Thursday, May 8th I had the privilege to attend a presentation at the Library of Congress by Alistair Miles, key developer of SKOS, and semantic web practitioner at the University of Oxford. The presentation was held at the Library of Congress because they are very interested in using this emerging technology for their catalog. SKOS is very close to becoming the W3C standard for publishing thesauri, classification schemes and subject headings as linked data in the Web. SKOS is built upon Resource Description Framework (RDF) and its main objective is to enable easy publication of controlled structured vocabularies for the Semantic Web. SKOS was developed to provide a more simplified alternative to OWL.

Alistair started out the presentation by demonstrating the value of HTML links and how they have made web pages and the Internet more accessible. He then described SKOS as the standard means of linking data across the Internet. SKOS has concepts of a label, alternate labels, notes, broader and narrower where the label is the title, alternate labels are different spellings, notes are a description and broader and narrower attributes are used to link to related concepts.

RDF was developed as a means to declare metadata of resources in a standard way. An RDF description of a resource contains a subject, predicate and object where the subject is the title of the resource, the predicate is the type of resource, and the object can be data or another resource. RDF is basically a standard XML schema for defining resources such as music, books, articles, etc. For an example take a look at the following from Dublin Core. An example of using RDF in an XHTML file is as follows:

    Jo Smith.    Web hacker    at          Example.org    .    You can contact me          via email    .

This example contains several attributes with the word “contact” in it. Each attribute defines a piece of the contact information, for example, the attribute contact:fn defines the contacts first name.

If you have a need for linking data in your web applications take a closer look at the technologies above for use in your application.