The RDF metadata model is based upon the idea of making statements about resources in the form of subject-predicate-object expressions, called triples in RDF terminology... RDF

Metadata, or structured data about data, improves discovery of and access to such information. The effective use of metadata among applications, however, requires common conventions about semantics, syntax, and structure... intro at

What is meant by "semantic" in Semantic Web is not that computers are going to understand the meaning of anything, but that the logical pieces of meaning can be mechanically manipulated by a machine to useful human ends... more

RDF: Resource Description Framework

Definition: The Resource Description Framework (RDF) is a standardised information modelling system that provides the means to organise substantially web-based information into a format that is readily usable by computers.



Background to RDF

The Internet provides a vast repository of information, but the key to its value is in the ability to retrieve the information required when required. As the web's search engines have tried to meet that demand, the difficulties have become increasingly clear: in fact, it's practically impossible for a computer system to assimilate the wide variety of data available on the web, created for a human audience, and respond to queries and searches on that data with any certainty of relevancy.

The problem lies in the fact that the information held on the Internet is designed for human readers, who have a sharp eye for semantics. Computers, however, do not have the ability to make sense of information that would be transparent to human readers. When computers see the Internet they simply see the markup language, images and so on. They have no way of understanding the meaning of the content.

The Solution

As a solution, the World Wide Web Consortium (W3C) developed the Resource Description Framework (RDF) as a method by which web resources can be encoded with machine-readable metadata, allowing computers to gather information more efficiently. Metadata is not new to the Internet, as, for example, keyword and description tags have been available for a long time, which were intended as a means to improve information organisation for computers. Although useful initially, this system was too open, and consequently suffered abuse. In many ways, RDF is simply a more formalised system of metadata using XML as the basis.

How RDF Works

RDF is built on simple statements which can be organised in "triples", a method of describing a statement according to its subject, predicate and object. For example, take the following statement:

This document was written about the Resource Description Framework.

In this example, the subject (‘This document’), predicate (‘was written about’) and object (‘the Resource Description Framework’) could be expressed in RDF and inserted in the head of this web page. When a computer reads this RDF triple it would be able to understand the information contained within the page, rather than relying on attempting to value keywords in the page text.

This coupled with other useful RDF triples can be used to describe every piece of information held on the Internet, potentially rendering all web data in a way that can be understood, organised, and far more efficiently used by computers, forming the basis of the semantic web.

The Semantic Web

Semantic Web’ is the term used to describe the next generation of the Internet - an Internet that is fully readable by computers

The potential benefits of a semantic web for business are enormous. Providing a method by which computers can reliably gather data from the Internet would significantly increase the pool of intelligence available to enterprises while at the same time reducing the financial burden of gathering data. The semantic web will not only make the use of search engines more reliable, it will also open the door to applications that can roam the Internet and collate information automatically on the behalf of enterprises. Once this information is accrued, the Resource Description Framework can be equally applied to data held on a corporate Intranet, allowing employees to search through it in much the same way as they would search through the semantic web.