The Semantic Web - Social Semantics: The Search for Meaning on the Web - page 57

http://www.example.org/hasArchitect

http://www.example.org/EiffelTower

http://www.example.org/GustaveEiffel

refers

refers

refers

is architect of
relationship

Gustave Eiffel Himself

The Eiffel Tower Itself

Fig. 3.2 An example RDF statement

3.2.2 RDF and the Principle of Linking

The second step in Berners-Lee's vision for the Semantic Web, “allowing links to be
created with relationship values,” follows straightforwardly from the application of
the Principle of Universality to knowledge representation. Since RDF is composed
of resources, and any resource may link to another resource, then any term in RDF
may be linked to another term. This linking forms the heart of RDF, as it allows
disparate URIs to be linked together in order for statements in RDF to be made.
The precise form of a statement in RDF is a triple , which consists of two resources
connected by a link, as shown in Fig. 3.2 . This use of RDF shows off the flexibility
of using URIs and links for reference instead of access. Lastly, this use of URIs
and links outside Web representations like those of hypertext web-pages shows the
flexibility of the linking paradigm, as RDF is an example of the use of the idea
of a linkbase that was developed in the hypertext community, in particular in the
Microcosm hypertext system, a pre-Web forebear that failed due to not being based
on open standards and also not being based on the Internet (Fountain et al. 1990).
Web representations in some form of Semantic Web language such as RDF are
called Semantic Web documents . There are several options for encoding Semantic
Web documents. The W3C standardized encoding of RDF is the verbose XML
format 'RDF/XML' although a simpler encoding called Turtle exists. In Turtle, a
triple is three space-delimited terms (the subject, predicate, and object) ended in
a period:
http://www.example.org/EiffelTower
http://www.example.org/hasArchitect
http://www.example.org/Gustave Eiffel