What's the relationship between OWL, RDFs, RDFa, Dublin Core and FOAF?

Semantic web can be described as Layer Structure.开发者_JS百科 we have URI in the button layer which is the unique identifier for data. and then we hay syntax like : xml, ns and xml xmls next it is the way how can we interpret semantic data : RDF and above RDF, we have RDFs, and OWL is independent from RDFs? but OWL, Dublin Core and FOAF is kind of RDFa? what's the structure between those ?

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Dublin Core and FOAF are schemas, i.e. vocabularies you can use to mark up your data.

OWL (and RDFS) are languages for writing new schemas / vocabularies / ontologies. OWL and RDFS schemas are written using RDF.

RDFa is a syntax for writing RDF (other examples are RDF/XML and Turtle).

Yes, this is all quite confusing!