There are two primary aspects to Semantic Web programming: knowledge representation and application integration. This section focuses on the former–representing and manipulating knowledge using the resource description framework (RDF) data model, ontologies (OWL), queries, rules, and reasoning. Each of the five chapters in this section builds the foundations of knowledge representation in the Semantic Web.
Chapter 3 establishes the data model of the Semantic Web: the Resource Description Framework (RDF). The chapter highlights the key differences between RDF and other traditional data representations like XML or relational databases, pointing out the distinction between syntax and semantics. RDF provides a flexible and highly expressive data model onto which the Semantic Web is built. All information in an RDF model can be conceptualized as statements about resources. These statements are much like statements in the English language–they have subjects, predicates, and objects. This chapter presents the features and limitations of RDF and introduces its abstract structure as well as its numerous concrete syntaxes.
Chapter 4 uses the OWL Web Ontology Language to add semantics to the RDF data model. OWL provides a vocabulary of terms that can be used in RDF statements. These terms have special semantics associated with them that are used to give meaning to the data they describe.
Semantics provide rich meaning such as taxonomical relationships ...