Semantic Web The Web with Semantics What is

Semantic Web The Web with Semantics

What is the Semantic Web? Knowledge Representation on the (decentralized) web. ¡ Definitions from Google ¡

Key Features of the Semantic Web ¡ Content meaningful to computers l XML, RDF Defining the world in objects (xml) ¡ URIs, not words, for concepts and associations. ¡ Decentralized and open ¡ l anyone can publish data about anything

Decentralized and Open ¡ ¡ Anyone can define attributes of anything. Berner’s Lee says Web doesn’t discriminate between “paper napkins” and well-thought out refereed articles. Is this true?

The Old Web dynamic page static page Servlet Database Server

The Web with Semantics Database Servlet rdf xml Service Database Server

The Web with Semantics Database Servlet rdf xml Service Database Server Objects, Associations, Reasoning Rules

3 -Layer DB Approach on the Web Servlet Software Agent rdf xml Service Database Server

Sample Questions for the Semantic Web Find the Ms. Cook I met at a trade conference last year. ¡ Get me a list of all academic publications concerning metasearch systems ¡

Traditional Knowledge Representation Closed Systems that can’t talk to each other ¡ Narrow, Idiosyncratic ¡

Knowledge Representation on Web RDF is the glue ¡ Formerly closed systems can publish RDF ¡ Can also publish RDF translators vis -à-vis similar systems ¡ There’s a lot of low hanging fruit. ¡

XML ¡ XML clause is: l property: string <-> value: string ¡ ¡ <lastname> wolber </lastname> An object is a hierarchical set of clauses l <person> l l ¡ <lastname> wolber </lastname> <firstname> david </firstname> </person>

RDF adds universality and subjects to each clause ¡ RDF Clause is a triple l subject: uri – property: uri – value: uri l <cs. usfca. edu/wolber> <foaf: last> <wolber> l l l <cs. usfca. edu/wolber> <foaf: first> <wolber>

XML vs. RDF <person> > > <lastname> wolber </lastname <firstname david </firstname> </person> <cs. usfca. edu/wolber> <foaf: last> <wolber> <cs. usfca. edu/wolber> <foaf: first> <wolber>

Property is a URI Can go there and see precise definition ¡ Allows standards to build up ¡ l ¡ e. g. , dublin core, foaf People can write equivalence equations with RDF.

In-Class Research Assignment There is foaf, dublin core, rdf ¡ Let’s compile a catgorized listing of all rdf schemas, including those. ¡ Films, Books, relationships between people… ¡ Let’s build a wiki page on it. ¡