The Semantic Web is generally built on syntaxes which use URIs to represent data, usually in triples based structures: i.e. many triples of URI data that can be held in databases, or interchanged on the world Wide Web using a set of particular syntaxes developed especially for the task. These syntaxes are called “Resource Description Framework” syntaxes.
Based on the metadata, intelligent applications such as semantic portals can be created. Metadata creation includes two major parts. First, the ‘Ontologies’ and vocabularies used as the basis in metadata descriptions are defined. Second, the web resources are annotated with metadata conforming to the definitions.
A crucial question for the breakthrough of the Semantic Web approach is how easily the needed metadata can be created. Annotating data by hand is laborious and resource-consuming and usually economically infeasible with larger datasets. Automation of the annotation process is therefore needed.
Semantic Web has generally but not finally five basic building blocks:
- URIs: A global naming scheme
- RDF: A standard syntax for describing data
- RDF Schema: A standard means of describing the properties of that data.
- OWL: A standard means of describing relationships between data items (ontologies defined with the OWL Web Ontology Language)
We are not going to cover these all in detail here however below is a little explanation of URI and RDF (Resource Description Framework).