The next generation web Part 2
Tools
Three tools are available to design Semantic Web
documents.
i)XML - eXtensible Mark-up Language
XML is known to all of us. Whose main purpose is to provide users the flexibility of creating their own tags, hidden labels that annotate web pages or sections of text on a page. In short, XML allows users to add arbitrary structure to their documents but says nothing about the meaning of structures.
ii) RDF- Resource Description Framework
Who does the role of assigning meanings to the key words identified by XML tags?. Yes it’s the functionality of RDF. It encodes each English sentence into a set of triples - each triple comprising of a subject, an object and a verb. In RDF, a document makes assertions that particular things (Dhoni) have properties (such as ‘is a hard hitting,’) with certain values (such as batsman). The subject, object and verb are identified by URI - Universal Resource Identifier which is analogous to hyperlinks of our ordinary web.
Assigning meanings to key words by RDF is not the end of the problem. Quite often, data with same meaning will be referred to by
different names in database of various sites. For instance, zip code of a city might be referred to as ‘zip-code’ in some database, as simple ‘zip’ in some site or as ‘pin-code’ in another site. So, who maps all these key words and identifies them to be carrying the same meaning? Here comes OWL
iii) OWL- Web Ontology Language
It is Web Ontology Language that does the functionality of correlating different terminologies. It is derived from a field of study called Ontology. Ontology is a theory about nature of existence. It describes what type of objects exists. Both ‘web’ researchers and AI experts have adapted Ontology to their respective areas as per their requirements.
For tutorials about building your own Semantic Web document log on to: www.w3schools.com/semweb/default.asp
The significance of URI is illustrated by Tim Berners-Lee and co-authors in an article to 'Scientific American' magazine as follows: Imagine that a business man hires a Robot to send new-year greetings to all customers in his database. The Robot failing to distinguish between customers'
addresses and that of Telephone department, Electricity dept and other offices sends greetings to all the addresses in the database-a clear instance of Automation failure. In such circumstances if he had used different URIs to distinguish between the types of addresses in his database, the automation could have been more reliable.