The Semantic Web

The Semantic Web

An introduction

In linguistics, semantics is … devoted to the study of meaning … on the syntactic levels of words, phrases, sentences

http://en.wikipedia.org/wiki/Semantic

Title

Author

Publisher

Genre

Price

“The Semantic Web is a web of data, in some ways like a global database”1

“first step is putting data on the Web in a form that machines can naturally understand, or converting it to that form.  This creates what I call a Semantic Web-a web of data that can be processed directly or indirectly by machines”2

1. http://www.w3.org/DesignIssues/Semantic.html

2. Tim Berners-Lee, Weaving the Web. Harper, San

Francisco. 1999.

<h1>Library Management Team</h1><h2>Director of Library Services</h2> <p>Deborah Shorley - Director of Library Services<br /><a href="mailto:[email protected]">[email protected]</a><br />Telephone: +44 (0)20 7594 8881</p>

<h2>Assistant directors</h2> <h3>Assistant Director: Administration and Planning</h3> <p>Susan Howard<br /><a href="mailto:[email protected]">[email protected]</a><br /> Telephone: +44 (0)20 7594 8622<br /><a href="http://www.imperial.ac.uk/people/s.howard">www.imperial.ac.uk/people/s.howard</a></p>

<h3>Assistant Director: E-Strategy and Information Resources</h3> <p>Owen Stephens<br /><a href="mailto:[email protected]">[email protected]</a><br /> Telephone: +44 (0)20 7594 8829<br /><a href="http://www.imperial.ac.uk/people/o.stephens">www.imperial.ac.uk/people/o.stephens</a></p>

<h3>Assistant Director: Faculty Support Services for Learning and Research</h3>

<p>Liz Davis<br /><a href="mailto:[email protected]">[email protected]</a><br /> Telephone: +44 (0)20 7594 8877<br /><a href="http://www.imperial.ac.uk/people/e.davis">www.imperial.ac.uk/people/e.davis</a></p>

How do we get a semantic web?

• Slowly!• Applications getting better at

understanding human semantics (‘Top Down’)

• More structured formats are gaining wider use (‘Bottom Up’)

• More database driven sites, so less need for humans to understand it all

• ‘Semantic web’ applications appearing

Top Down

• Depends of ‘more intelligent’ computers– Google Book Search– LibX Toolbar

http://www.readwriteweb.com/archives/semantic_web_difficulties_with_classic_approach.php

Bottom Up

• Depends on more structured data using agreed standards– URIs– RDF– OWL

• Many sceptics– http://www.readwriteweb.com/archives/semantic_web_difficulties

_with_classic_approach.php

URI

• Uniform Resource Identifier– “a simple and extensible means for identifying

a resource”– A URL is a type of URI

What is RDF?

• Resource Description Framework– “a language for representing information about

resources in the World Wide Web”– “RDF can also be used to represent information about

things that can be identified on the Web, even when they cannot be directly retrieved on the Web”

– Uses URIs or Literals

http://www.w3.org/TR/REC-rdf-syntax/

Jane Eyre

has a

creator whose name is

Charlotte Bronte

Subject

Predicate

Object

Jane Eyre

has a

creator whose name is

Charlotte Bronte

Subject

Predicate

Object

http://purl.org/dc/elements/1.1/creator

http://www.gutenberg.org/files/1260/1260-h/1260-h.htm

Charlotte Bronte

Jane Eyre

Charlotte Bronte

Penguin

Book

is a

has creator

has publisher

Person

is a

RDF Schemas

• Define vocabularies for a community– Define a class of objects ‘Books’– Define a property ‘Creator’

OWL (Web Ontology Language)

• When a Schema just isn’t enough!

• Allows you to put limits of relationships– a Person has one and only one biological

mother

• Allows you to say ‘this is the same as that’– This thing that I call a ‘Car’ is the same as that

thing that you call an ‘Automobile’

Some actual applications!

• Cinespin (Freebase)

• Nugget, Cenote (Talis)

• RDA, DCMI, FRBR, FRAD etc.

Acknowledgments

• Jane Eyre– http://www.flickr.com/photos/andthenpatterns/

• Sad Computer– http://www.flickr.com/photos/loririelly/

• Power of Three– http://www.flickr.com/photos/hale_popoki