Introduction to the Semantic Web



Tim Berners-Lee



Decentralized Information Group
MIT Computer Science and Artificial Intelligence Laboratory


Web rules



Semantic Web



SW: Everything has a URI

Don't say "colour" say <>

The relational database

A database's row, column and cell are subject, property and value.

The element of the Semantic Web

arrow tail, body and head are l are subject, property and value.

Semantic web includes tables,...

Arrows can make a table, an arrow from each row to each value


Arrows can make a table, an arrow from each row to each value

... everything

Arrows can make a table, an arrow from each row to each value

RDF data...

a set of circles and arrows

...merges just like that.

more circles and arrows superim

Subject and object node using same URIs

RDF: Semantic links - "Joining the Web"

 Links between column headings

Verb/predicate/Property using same URIs

Communities and Vocabularies

Universal WWW must include communities on many scales

Applications connected by concepts

Its like a metro, the way the lines of common concepts connect the stations of different applications

For example in biopax

Venn diagram showing ontologies overlapping by certain common terms

[Diagram: Joanne Luciano, Predictive Medicine; Drug discovery demo using RDF, Sideran Seamark and Oracle 10g]

Fractal Web of concepts

The semantic web is about allowing data systems to change by evolution not revolution

Total Cost of Ontologies (TCO)

Assume :-) ontologies evenly spread across orders of magnitude; committe  size as log(community), time as comitee^2, cost shared across community.
Scale Eg Committe size Cost per ontology (weeks) My share of cost
0 Me 1 1 1
10 My team 4 16 1.6
100 Group 7 49 0.49
1000 10 100 0.10
10k Enterprise 13 169 0.017
100k Business area 16 256 0.0026
1M 19 361 0.00036
10M 22 484 0.000048
100M National, State 25 625 0.000006
1G EU, US 28 784 0.000001
10G Planet 31 961 0.000000

Total cost of 10 ontologies: 3.2 weeks. Serious project: 30 ontologies, TCO = 10 weeks.
Lesson: Do your bit. Others will do theirs.
Thank those who do working groups!

Clients of the RDF bus

New data applications can be built on top of RDF bus, for example:

db to sw

Future: Stack of expressive power

architectural layers

The Semantic Web Wave

The wave is coming...get out your surfboard

Current Semantic Web work at W3C


Adoption challenges

Good news

More Information

Creative Commons License
This work is licensed under a Creative Commons Attribution - Non-Commercial - No Derivatives 2.5 License.
Semantic Web URIs2006slides Tim Berners-LeeMIT