RDF is a way of presenting knowledge, relationship or a thing in the format of triples. For everything in the web will be represented as a triples format. As we know about grammer we read it in our child hood, like every basic sentence is represented as format of triples. That means subject, predicate & objects.
FOAF:
FOAF is the vocabulary to represent RDF the objects & relationship between them. FOAF is a way of describing a person / company. FOAF is Friend of A friend using RDF to represent its data. It will describe a person in the following way.
nandakumar -> is -> http://www.desiji.com/ndotnanda
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:foaf="http://xmlns.com/foaf/0.1/"> <foaf:Person> <foaf:name>Nandakumar</foaf:name> <foaf:mbox rdf:resource="http://www.desiji.com/ndotnanda"/> </foaf:Person> </rdf:RDF> N3 Notation & triples: A syntax to represent RDF. @prefix pref <http://www.example.org/vacobulary #>. <#nandakumar><pref:working><#ndot> RDFa: RDFa is way to integrate RDF into XHTML pages. It reduces the lot of work & difficulties for normal people those who want to represent their blog / personal data into semantic web. RDFa helps them to represent their information to semantic web with XTHML. we can take an small example about how we can represent a data with RDFa, Here we are going to explain a FOAF integration into XHTML page. Triples: Nandakumar knows Preethi RDFa: <body xmlns:foaf="http://xmlns.com/foaf/0.1"> <span about="#Nandakumar" property="foaf:name"> Nandakumar Somasundaram </span> </body> Triple : Nandakumar -> Name -> Nandakumar Somasundaram RDFa : example 2<body xmlns:foaf="http://xmlns.com/foaf/0.1"> <span about="#Nandakumar" property="foaf:name"> Nandakumar Somasundaram </span><span about="#Preethi" property="foaf:name"> Preethi </span> <span about="#Nandakumar" rel="foaf:knows" resource="#Preethi"> Nandakumar is classmate of preethi </span</body>
Road to the Future 