Semantic

THE SEMANTIC WEB

Having computers understand things more like human beings do

The current Web represents information using

-natural language (English,Hungarian,Chinese).-graphics,multimedia, page layout.

Humans can process this easily - can deduce facts from partial information. - can create mental association. - are used to various sensory information.

Tasks often require to combine data on the Web.- Hotel and Travel information may come from different websites.- searches in different digital libraries.

Humans can combine these information easily.- even if different terminologies are used.

However , machines are ignorant.- partial information is unusable.

- difficult to make sense from, e.g ,an image.- difficult to combine information automatically.

Semantic Web - coined by Tim Berners-Lee inventor of WWW, URI, HTTP, HTML and

Semantic Web. “ a web of data that can be processed

directly and indirectly by machines . “ to access the Web more intelligently and

perform tasks on behalf of users . evolution of the current Web by enabling

users to find, share, and combine information more easily .

Why not just google ?Currently, users search for data on the Web by

asking questions that are of the form : “which documents contain these words and phrases ”

The Semantic Web will involve more related questions , relationships, and trust .

Instead of word matching the web will be able to show related items showing new relationships.

Semantic links

Web of Data

Architecture of Semantic Web

RDF (Resource DesciptionFramework)

RDF is the foundation of the semantic web .RDF = a simple conceptual data model

(GRAPH).RDF model = set of RDF triples . (subject, verb, object). A Sentence

Jane sells books.

subject predicate

object

RDF - ResourceResource is anything that has identity (URI).

-Jane, Book. (a govt agency, a human , an abstract concept)

RDF – Description several statements describing the resource.

RDF – FrameworkIt is needed to enable humans and machines to

make and understand statements . - Natural languages like English.

Human brain uses logicMary is a mother.A mother is a parent.Therefore, Mary must be a parent.

ONTOLOGYPrecise explanation of terms and reasoning in a

subject area. - Computers can act as if they understand the information they are handling.

The facts stored in the semantic web will change over time as the true state of world changes.