1. 1 Resource Description Framework (RDF) Presented by Igor Tatarinov

2. 2 RDF: Making Statements About Resources RDF statement: A triplet: object property subject Igor’s advisor is Alon Resources: Things, people, properties!, etc Need an ID!  URI: http://www.cs.washington.edu/#Igorhttp://www.cs.washington.edu/#Igor  Everyone’s free to design their own IDs !?

3. 3 RDF Data Model A graph! Each statement is an edge IgorAlon advisor status Piazza leader member “student”

4. 4 A Relational View of RDF RDF statement = “relationship” between 2 entities RDF graph = ER diagram The Internet is an RDBMS! Every table has a primary key (URI) Can’t control others’ tables Can join (make an RDF statement):  Faculty(Alon), Student(Igor) @UW  Can define Advisor(Alon, Igor) @UPenn

5. 5 Reification Can describe properties of an RDF statement stm1 Rdf:Statement Igor advisor Alon rdf:type rdf:object rdf:predicate rdf:object Zack creator

6. 6 RDF Syntax RDF uses XML: graduate student RDF adds “semantics” to XML Each Description is an RDF statement  Basically defines an XML schema for RDF  Any XML schema brings semantics!  RDF = a standard XML schema!

7. 7 RDF Application: Dublin Core Metadata Initiative Started in 1995 (before RDF) Goal: enable resource discovery on the Web Idea: embed special tags in HTML 15 standard “elements” (properties) Title, Subject, Description, Creator, etc 5 years to define the semantics! DC defines a standard RDF Schema 15 “standard” RDF properties A tiny standard ontology Defining a bigger standard ontology is hopeless !?

8. 8 RDF: “Forget about the Semantic Web hooey” David Megginson, 2000 RDF: technology for exchanging serialized objects: Just like XML Preserves more semantics than XML  Can recognize objects and properties w/o an additional schema  Supports a graph data model