Semantic Web Tutorial

The Semantic Web = a Web with a meaning. "If HTML and the Web made all the online documents look like one huge book, RDF, schema, and inference languages will make all the data in the world look like one huge database" Tim Berners-Lee, Weaving the Web, 1999

What Is The Semantic Web?

The word semantic stands for the meaning of. The semantic of something is the meaning of something.

The Semantic Web is a web that is able to describe things in a way that computers can understand.

• The Beatles was a popular band from Liverpool.
• John Lennon was a member of the Beatles.
• The record "Hey Jude" was recorded by the Beatles.

Sentences like these can be understood by people. But how can they be understood by computers?

Statements are built with syntax rules. The syntax of a language defines the rules for building the language statements. But how can syntax become semantic?

This is what the Semantic Web is all about. Describing things in a way that computers applications can understand.

The Semantic Web is not about links between web pages.

The Semantic Web describes the relationships between things (like A is a part of B and Y is a member of  Z) and the properties of things (like size, weight, age, and price)

The Resource Description Framework

RDF (Resource Description Framework) is a markup language for describing information and resources on the web.

Putting information into RDF files, makes it possible for computer programs ("web spiders") to search, discover, pick up, collect, analyze and process information from the web.

The Semantic Web uses RDF to describe web resources.

If you want to learn more about RDF please read our RDF tutorial.

How Can It Be Used?

If information about music, cars, tickets (and everything else) were stored in RDF files, intelligent web applications could collect information from many different sources, combine information, and present it to users in a meaningful way.

Information like this:

• Car prices from different resellers
• Information about medicines
• Plane schedules
• Spare parts for the industry
• Information about books (price, pages, editor, year)
• Who is who
• Dates of events
• Computer updates

Can It Be Understood?

The Semantic Web is not a very fast growing technology.

One of the reasons for that is the learning curve. RDF was developed by people with academic background in logic and artificial intelligence. For traditional developers it is not very easy to understand.

One fast growing language for building semantic web applications is RSS. If you want to learn more about RSS please read our RSS tutorial.

In the following pages of this tutorial we will concentrate on using RDF to discover the potentials of the semantic web.

Please move on to the next chapter to see a simple semantic web application example.