Ontologies and Linked Data

Abstract

4.1 The Data Model RDF RDF is the data model of linked data. It is an acronym for Resource Description Framework, a standard of the World Wide Web Consortium (W3C), currently in version 1.1.1 RDF is built on ideas coming from decades of work in Logic and Knowledge Representation. It is a very simple data model based on the concept of a triple to represent simple sentences such as “Athens is the capital of Greece.” An RDF triple (s, p, o) has three parts: the subject s, the predicate p, and the object o. The sub­ ject and predicate of a triple are IRIs2 while the object can be an IRI or a literal. Everything denoted by an IRI is called a resource in RDF. 3 If we want to use RDF to model the GADM database that we saw in Chapter 3, we should assign an IRI to each feature existing in GADM. For example, we can use the IRI http://ai.di.uoa.gr/gadm/Athens to represent the city of Athens. To represent datatype values in RDF, we use literals. Each lit­ eral has an associated data type defined by an IRI. For example,