Linked Data and the Semantic Web - What Are They and Should I Care?

UKOLN is supported by: Linked Data and the Semantic Web - What are they and should I care? 6 th October 2009 Manchester Social Media Caf é Adrian Stevenson UKOLN Project Manager and Technical Researcher

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

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

“ 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... 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.

“ The term Linked Data refers to a set of best practices for publishing and connecting structured data on the Web.”

“ the Semantic Web is the goal or end result… Linked Data provides the means to reach that goal”

From ‘ Linked Data: The Story So Far ’ - Heath, Bizer and Berners-Lee 2009

The Web We’re Used To

Made by humans for humans

Primarily documents

Machines not very welcome

Data silos

Web of Linked Data

In 1998 the idea from Tim Berners-Lee of ‘linked data’ took shape

Designed for machines first

It primarily links data about ‘things’, not documents

But haven’t we been putting data on the web for years?

In CSV , relational databases, XML etc?

Well yes, but these approaches are not so easy to integrate

Web 2.0 mashups work against a fixed set of data sources

Linked Data applications operate on top of an unbound, global data space.

So what’s happening now?

“ Sir Tim Berners-Lee, the inventor of the world wide web, will help the British government to make its data more easily available online … I have asked Sir Tim Berners-Lee … to help us drive the opening up of access to Government data in the web” Prime Minister Gordon Brown, 10 th June 2009

"What you find if you deal with people in government departments is that they hug their database, hold it really close”. Tim Berners-Lee, 10 th June 2009

We shall see …

A little bit of the techy stuff

Linked Data is …

A way of publishing data on the web that:

Encourages reuse

Reduces redundancy

Maximises inter-connectedness

Enables network effects

Presentational tagging – HTML

<h1>Agilitas Physiotherapy Centre</h1> <p>Welcome to the Agilitas Physiotherapy Centre home page. Do you feel pain? Have you had an injury? Let our staff Lisa Davenport, Kelly Townsend (our lovely secretary) and Steve Matthews take care of your body and soul.</p> <h2>Consultation hours</h2> Mon 11am - 7pm<br/> Tue 11am - 7pm<br/> Wed 3pm - 7pm<br/> Thu 11am - 7pm<br/> Fri 11am - 3pm

<p> But note that we do not offer consultation during the weeks of the <a href=". . .">State Of Origin</a> games.</p>

Semantic tagging

<company>

<treatmentOffered>Physiotherapy</treatmentOffered>

<companyName>Agilitas Physiotherapy Centre</companyName>

<staff>

<therapist>Lisa Davenport</therapist> <therapist>Steve Matthews</therapist>

<secretary>Kelly Townsend</secretary>

</staff>

</company>

Tim BL’s Linked Data Design Issues

Use URIs as names for things

Use HTTP URIs so that people can look up those names.

When someone looks up a URI, provide useful information, using the standards (RDF, SPARQL)

Include links to other URIs. so that they can discover more things.

From http://www.w3.org/DesignIssues/LinkedData.html

URIs and HTTP

A “Uniform Resource Identifier (URI) provides a simple and extensible means for identifying a resource –RFC 3986

A URL is a type of URI

HTTP URIs can be ‘de-referenced’

HTTP URIs for “real world” things

http://adrianstevenson.com/id/me

http://dbpedia.org/page/Tim_Berners-Lee

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”