1. Semantic Web
The Web with Semantics

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

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

4. 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?

5. The Old Web
dynamic page
static page
Servlet
Server
Database

6. The Web with Semantics Database Servlet Service Server Database rdf
xml
Service
Server
Database

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

8. 3-Layer DB Approach on the Web
Servlet
Software Agent
rdf
xml
Service
Server
Database

9. 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

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

11. 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.

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

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

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

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

16. 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.