Chapter 8 - Using RDFS-Plus in the Wild

Abstract

This chapter describes uses of SKOS (Simple Knowledge Organization System) and FOAF (Friend of a Friend). Both of these applications of RDFS-Plus (Resource Description Framework Schema Language) have attracted considerable user communities in their respective fields. Both of them also make essential use of the constructs in RDFS-Plus, though often in quite different ways. These are real modeling applications built by groups who originally had no technology commitment to RDFS or OWL (Web Ontology Language). In both cases, the projects are about setting up an infrastructure for a particular Web community. The use of RDFS-Plus appears in the models that describe data in these communities, rather than in the everyday use in these communities. SKOS and FOAF demonstrate how a fairly simple set of modeling constructs can be used to create extensible, distributed information networks. They both take advantage of the distributed nature of RDF to allow extension to a network of information to be distributed across the Web. Both of them rely on the inferencing structure of RDFS-Plus to add completeness to their information structure. Both of them use owl:InverseFunctionalProperty to determine the identity of key elements. Although they are similar in these ways, FOAF and SKOS are organized very differently in terms of how they support extension by their expected user communities. FOAF takes something of an evolutionary approach to information extension. SKOS, in contrast, takes a much more orderly approach to extension.