Chapter 3 Describing Web Resources in RDF Grigoris Antoniou Frank van Harmelen 1 Chapter 3 A Semantic Web Primer
1 Chapter 3 A Semantic Web Primer Chapter 3 Describing Web Resources in RDF Grigoris Antoniou Frank van Harmelen
Lecture Outline 1. Basic Ideas of rDF 2. XML-based Syntax of RDF 3. Basic Concepts of RdF Schema 4. The Language of rdf Schema 5. The Namespaces of RdF and rdf Schema 6. Axiomatic Semantics for rdf and rdfS 7. Direct Semantics based on Inference rules 8. Querying of RDF/RDFS Documents using RQL Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 2 Lecture Outline 1. Basic Ideas of RDF 2. XML-based Syntax of RDF 3. Basic Concepts of RDF Schema 4. Τhe Language of RDF Schema 5. The Namespaces of RDF and RDF Schema 6. Axiomatic Semantics for RDF and RDFS 7. Direct Semantics based on Inference Rules 8. Querying of RDF/RDFS Documents using RQL
Drawbacks of Xml XML is a universal metalanguage for defining markup It provides a uniform framework for interchange of data and metadata between applications However, XML does not provide any means of talking about the semantics(meaning) of data E.g., there is no intended meaning associated with the nesting of tags It is up to each application to interpret the nesting 3 Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 3 Drawbacks of XML ⚫ XML is a universal metalanguage for defining markup ⚫ It provides a uniform framework for interchange of data and metadata between applications ⚫ However, XML does not provide any means of talking about the semantics (meaning) of data ⚫ E.g., there is no intended meaning associated with the nesting of tags – It is up to each application to interpret the nesting
Nesting of Tags in XML David billington is a lecturer of Discrete Maths <course name="Discrete aths <lecturer David Billington</ecture <course> <lecturer name="David Billington"> <teaches>Discrete Maths/teaches> Lecturer Opposite nesting, same information Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 4 Nesting of Tags in XML David Billington is a lecturer of Discrete Maths <course name="Discrete Maths"> <lecturer>David Billington</lecturer> </course> <lecturer name="David Billington"> <teaches>Discrete Maths</teaches> </lecturer> Opposite nesting, same information!
Basic deas of rdf e Basic building block: object-attribute-value ple It is called a statement Sentence about Billington is such a statement RDF has been given a syntax in XML This syntax inherits the benefits of XML Other syntactic representations of RDF possible 5 Chapter 3 A Semantic Web primer
Chapter 3 A Semantic Web Primer 5 Basic Ideas of RDF ⚫ Basic building block: object-attribute-value triple – It is called a statement – Sentence about Billington is such a statement ⚫ RDF has been given a syntax in XML – This syntax inherits the benefits of XML – Other syntactic representations of RDF possible