Introduction To RDF and RDFS
- 1. Introduction to RDF and RDFS BY Tushar Dongare
- 2. RDF Concept RDF stands for Resource Description Framework. RDF is a framework for describing resources on the web. RDF is designed to be read and understood by computers. RDF (i.e RDF/XML) is a W3C Recommendation (for Semantic Web). RDF is written in XML
- 3. RDF Concept How to describe resources ? Decompose knowledge or fact of resource into small pieces. In Method and not the format. Comparing with XML XML is not concerned with meaning. XML standard doesn't indicate how to derive a fact from a document.
- 4. Decomposition of knowledge into small pieces is called triple (statement). Triple is made of three parts. Triples SUBJECT OBJECT PREDICATE
- 5. Triple Example Subject and Object denotes the real world entities. Predicate is relationship between them. amravati is_in my_house my_bed has my_house my_computer has my_house my_house own I OBJECT PREDICATE SUBJECT
- 6. URI 2 Name Resources Names must be global. Names for subjects, predicates, and objects must be Uniform Resource Identifiers. Let tushar: abbreviate http://tushar.myhomepage.com/index.html# And ex: abbreviate http://example.com/
- 7. URI 2 Name Resources RDF as a Graph
- 8. Semantic Web : Three Rules A fact is expressed as a triple of the form (Subject, Predicate, Object). Subjects, predicates, and objects are given as names for entities, whether concrete or abstract, in the real world. Names are in the format of URIs, which are opaque and global.
- 9. Reading and Writing RDF <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#" xmlns:edu="http://www.example.org/"> <rdf:Description rdf:about="http://www.coebadnera.com"> <geo:lat>40.35</geo:lat> <geo:long>-74.66</geo:long> <edu:hasDept rdf:resource="http://www.coebadnera.com/IT#"/> </rdf:Description> <rdf:Description rdf:about="http://www.coebadnera.com/IT#"> <dc:title>Department of Information Technology</dc:title> </rdf:Description> </rdf:RDF>
- 10. Reading and Writing RDF ……… <rdf:Description rdf:about=" http://www.coebadnera.com "> <geo:lat>40.35</geo:lat> <geo:long>-74.66</geo:long> <edu:hasDept> <rdf:Description rdf:about="http://www.coebadnera.com/IT#"> <dc:title> Department of Information Technology </dc:title> </rdf:Description> </edu:hasDept> </rdf:Description>
- 11. Choosing The Right Predicates WHY ? Piece of knowledge is not automatically interpretable. If two RDF documents with no URIs in common, there is no information that can be interrelated. For Example Let consider information from Google Book and Amazon.com about book in RDF Format.
- 12. Choosing The Right Predicates <urn:isbn:0143034650> dc:title "Pro ASP.NET 3.5" <urn:isbn:0613917472> dc:title "Laws of Cyberspace" <urn:isbn:B00005U7WO> dc:title "System Simulation" From Google Book <urn:isbn:0143034650> amazon:price "$20.00" <urn:isbn:0613917472> amazon:price "$30.00" <urn:isbn:B00005U7WO> amazon:price "$40.00" From Amazon.com (automatically interpretable for two application)
- 13. Meshing The Information Example : Product Vender and Reviewer Meshup of Data Vender 1 with Product_X Product_Y Product_Z Vender 2 with Product_Y Product_Z Vender 3 with Product_A Product_B Product_Z Reviewer 1 for Product_X Product_A Product_B Reviewer 2 for Product_Y Product_Z Reviewer 3 for Product_Z Product_X
- 14. RDFS : RDF Schema RDFS extends RDF such that it is RDF which describe other RDF. Ontologies, schemas and vocabularies which all mean roughly the same thing. Purpose is to show applications how some information should be interpreted. RDF Schema (RDFS) introduces the notion of a class. Here a class is a type of thing.
- 15. RDF Schema : Example rdf:type class is first higher-level predicate. <urn:isbn:0143034650> rdf:type general:Book <urn:isbn:0613917472> rdf:type general:Book One interesting class is rdf:Property dc:title rdf:type rdf:Property amazon:price rdf:type rdf:Property RDFS predicates can provide even more information like rdfs:range predicate dc:title rdfs:range rdfs:Literal
- 16. RDF Schema : Example rdfs:subClassOf relation indicates that one class is a sub-class of another. Animal Dog rdfs:subClassOf
- 17. Criticism of RDF RDF has been criticized in 2001 on the following grounds The XML syntax for RDF is too verbose. The triple notation simplicity introduces reading and computation disadvantages. RDF's ability to reify statements allows for uncertainty.
- 18. Conclusion For Semantic Web interoperability: All items of interest, such as information resources, real-world objects and vocabulary terms are identified by URI references. URI references are dereferenceable. Descriptions are provided using the RDF/XML syntax. Every RDF triple is conceived as a hyperlink that links to related information from the same or a different source.
- 19. Thank You! rdfabout.com http://www.w3.org/TR/2004/REC-rdf-concepts-20040210/