wtf is the semantic web and linked data

WTF is the Semantic Web and Linked Data

Juan F. SequedaDepartment of Computer Science

University of Texas at AustinNov 17, 2011

Semantic Web? Linked Data?

WTF?

WTF is the Semantic Web?

Internet != Web

What is the Web?

“… the Web, is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view web pages that may contain text, images […] and navigate between them via hyperlinks”

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

Current Web = internet + links + docs

History of the Web

• Created by Tim Berners-Lee at CERN in 1989• Mosaic browser in 1993• W3C created in 1994• Exponential growth mid 90s• Amazon, Ebay – 1995• Search engines – Google 1998• Dot-com boom 1997 – 2001• Web 2.0 – blogs, Facebook, Twitter, etc

What is the problem?

WHAT’S THE WEATHER IN

AUSTIN TODAY?

http://www.flickr.com/photos/jamieca/31631256/

What is the problem?

• The web is full of documents• We aren’t always interested in documents

– We are interested in THINGS– These THINGS might be in documents

• We can read a HTML document rendered in a browser and find what we are searching for– This is hard for computers. – Computers have to guess (even though they are

pretty good at it)

The Web of Documents

Search

Crawler

Search Engine

The Web is a Data Shredder

Structured Data

Unstructured Data

Thanks Martin Hepp

What would we like?

• Make it easy for computers/software to find THINGS

Do you SEARCH or do you FIND?

Search for

Football Players who went to the University of Texas at Austin, played for

the Dallas Cowboys as Cornerback

Why can’t we just FIND it…

Guess how I FOUND out?

On a Semantic Web

• Besides publishing documents on the web– which computers can’t understand easily

• Let’s publish on the web something that computers can understand

DATA

The Semantic Web is a web of data

The current web is a web of documents

But wait… doesn’t the web already have data?

Current Data on the Web

• Relational Databases• APIs• XML• CSV• XLS• …• Can’t computers and applications already

consume that data on the web?

Yes! But it is all in different formats and data models!

This makes it hard to integrate data

The data in different data sources aren’t linked

For example, how do I know that the Juan Sequeda in Facebook is the same as Juan

Sequeda in Twitter

Or if I create a mashup from different services, I have to learn different APIs and I get different

formats of data back

Data is Siloed

Wouldn’t it be great if we had a standard way of publishing data on the Web?

We have a standardized way of publishing documents on the web, right?

HTML

Then why can’t we have a standard way of publishing data on the Web?

Good question! And the answer is YES. There is!

RDF

Resource Description Framework (RDF)

• Data Model = a way to model data– i.e. Relational databases use relational data model

• RDF is a graph data model

Key Value vs Graph

• Key Values– firstName Juan– lastName Sequeda– livesIn Austin– knows Stephane Corlosquet

• But what are these key/values describing?– ME!

RDF is a Graph

• Let’s group the Key/Values together– <JuanSequeda> <firstName> “Juan”– <JuanSequeda> <lastName> “Sequeda”– <JuanSequeda> <livesIn> “Austin”– <JuanSequeda> <knows> <StephaneCorlosquet>– ..– <StephaneCorlosquet> <firstName> “Stephane”– <StephaneCorlosquet> <lastName> “Corlosquet”– <StephaneCorlosquet> <livesIn> “Boston”

RDF is a Graph

• Let’s group the Key/Values together– <JuanSequeda> <firstName> “Juan”– <JuanSequeda> <lastName> “Sequeda”– <JuanSequeda> <livesIn> “Austin”– <JuanSequeda> <knows> <StephaneCorlosquet>– ..– <StephaneCorlosquet> <firstName> “Stephane”– <StephaneCorlosquet> <lastName> “Corlosquet”– <StephaneCorlosquet> <livesIn> “Boston”

Key/ValueIdentifier for the “group”

RDF can be serialized in different ways

• RDF/XML• RDFa (RDF in HTML)• N3• Turtle• JSON

RDF/XML

RDF/N-triples

RDF/Turtle

So does that mean that I have to publish my data in RDF now?

You don’t have to… but we would like you to

Schema.orgRich Snippets

…

An example

Document on the Web

Databases back up documents

Isbn Title Author PublisherID ReleasedData

978-0-596-15381-6

Programming the Semantic Web

Toby Segaran 1 July 2009

… … … … …

PublisherID PublisherName

1 O’Reilly Media

… …

This is a THING:A book title “Programming the Semantic Web” by Toby Segaran, …

THINGS have PROPERTIES:A Book as a Title, an author, …

Lets represent the data in RDF

book


978-0-596-15381-6

Toby Segaran

Publisher O’Reilly

title

name

author

publisher

isbn

Isbn Title Author PublisherID ReleasedData

978-0-596-15381-6


Toby Segaran

1 July 2009

PublisherID PublisherName

1 O’Reilly Media

Remember that we are on the web

Everything on the web is identified by a URI

And now let’s link the data to other data

http://…/isbn978


978-0-596-15381-6

Toby Segaran

http://…/publisher1 O’Reilly

title

name

author

publisher

isbn

And now consider the data from Revyu.com

http://…/isbn978

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda

hasReview

reviewer

description

name

Let’s start to link data

http://…/isbn978


978-0-596-15381-6

Toby Segaran


title

name

author

publisher

isbn

http://…/isbn978

owl:sameAs

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda

hasReview

hasReviewer

description

name

Juan Sequeda publishes data too

http://juansequeda.

com/id

livesIn

Juan Sequedaname

http://dbpedia.org/Austin

Let’s link more datahttp://…/isbn978

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda

http://juansequeda.

com/id

hasReview

hasReviewer

description

name

sameAs

livesIn

Juan Sequedaname


And more

http://…/isbn978


978-0-596-15381-6

Toby Segaran

http://…/publisher1

O’Reilly

title

name

author

publisher

isbn

http://…/isbn978

owl:sameAs

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda

http://juansequeda.

com/id

hasReview

hasReviewer

description

name

owl:sameAs

livesIn

Juan Sequedaname


Data on the Web that is in RDF and is linked to other RDF data is

LINKED DATA

Linked Data Principles1. Use URIs as names for

things2. Use HTTP URIs so that

people can look up (dereference) those names.

3. When someone looks up a URI, provide useful information.

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

Linked Data makes the web appear as ONE

GIANTHUGE

GLOBAL

DATABASE!

I can query a database with SQL. Is there a way to query Linked Data with a query language?

Yes! There is actually a standardize language for that

SPARQL

FIND all the reviews on the book “Programming the Semantic Web” by people who live in Austin

SELECT ?review ?commentWHERE { isbn:978 ex:hasReview ?review . ?review ex:description ?comment . ?review ex:hasReviewer ?person . ?person ex:lives dbpedia:Austin .}

SPARQL

http://…/isbn978


978-0-596-15381-6

Toby Segaran


title

name

author

publisher

isbn

http://…/isbn978

sameAs

http://…/

review1

Awesome Book

http://…/

reviewer

Juan Sequeda

http://juansequeda.

com

hasReview

hasReviewer

description

name

sameAs

livesIn

Juan Sequedaname


SELECT ?review ?commentWHERE {isbn:978 ex:hasReview ?review .?review ex:description ?comment .?review ex:hasReviewer ?person .?person ex:lives dbpedia:Austin .}

OWL

• Here is where the real semantics shows up• Web Ontology Language• Define schema/vocabulary• Classes, Properties, Inheritance, etc• Subclasses, Subproperties• …• You can get more complicated with rules…

dexa:TirmiziSM08

auth: <http://dblp.l3s.de/d2r/page/authors/>dexa: <http://dblp.l3s.de/d2r/page/publications/conf/dexa/>dc: <http://purl.org/dc/elements/1.1/>sw: <http://data.semanticweb.org/person/>swrc: <http://swrc.ontoware.org/ontology#>owl: <http://www.w3.org/2002/07/owl#>rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>rdfs: <http://www.w3.org/2000/01/rdf-schema#>

auth:Juan_Sequeda

auth:Daniel_P._Miranker

auth:Syed_Hamid_Tirmizi

dc:creator

dc:creatordc:creator

“Translating SQL Applications to the

Semantic Web"

dc:title

sw:juan-f-sequeda

sw:daniel-miranker

sw:syed-tirmizi

foaf:Personswrc:InProceedings

swrc:Publication

dc:creator

rdf:type

rdf:type

rdfs:subClassOf

owl:sameAs

owl:sameAs

owl:sameAs

OWL

RDF

RDB and the Semantic Web

74

RELATIONAL MODEL

TABLE DEFINITION

CONSTRAINTS

TRIGGERS

RDF

RDFS

OWL

RIF

TIM

E

This looks cool, but let’s be realistic. What is the incentive to publish Linked Data?

What was your incentive to publish an HTML page in 1990?

1) Share data in documents2) Because you neighbor was doing it

… later on …3) Marketing, Advertising, …, SEO

So why should we publish Linked Data in 2011?

1) Share data as data2) Because you neighbor is doing it

…3) Marketing, Advertising, SEO ++

Linked Data Publishers• UK Government• US Government• BBC• Open Calais – Thomson Reuters• Freebase/Google• NY Times• Best Buy• Sears• Kmart• Overstock.com• CNET• Dbpedia• O’Reilly Media• …

May 2007

Oct 2007

Nov 2007

Feb 2008

Mar 2008

Sept 2008

Mar 2009 (1)

Mar 2009 (2)

July 2009

September 2010

September 2011

Linking Open Data cloud diagram, by Richard Cyganiak and Anja Jentzsch. http://lod-cloud.net/

YOU GET THE PICTURE

ITS BIG and getting

BIGGER and

BIGGER

What is the Web

• Web of Documents HTML• Web of Data RDF• Global Unique IDs HTTP URIs• Schema/Ontologies OWL• Query RDF SPARQL

Now what can we do with this data?

Generic Applications

Linked Data Browsers


• Not actually separate browsers. Run inside of HTML browsers

• View the data that is returned after looking up a URI in tabular form

• User can navigate between data sources by following RDF Links

• (IMO) No usability


• http://browse.semanticweb.org/• Tabulator• OpenLink Dataexplorer• Zitgist• Marbles• Explorator• Disco• LinkSailor

Linked Data (Semantic Web) Search Engines

Linked Data (Semantic Web) Search Engines

• Just like conventional search engines (Google, Bing, Yahoo), crawl RDF documents and follow RDF links.– Current search engines don’t crawl data, unless it’s RDFa

• Human focus Search– Falcons - Keyword– SWSE – Keyworkd– VisiNav – Complex Queries

• Machine focus Search– Sindice – data instances– Swoogle - ontologies– Watson - ontologies– Uberblic – curated integrated data instances

(Semantic) SEO ++

• Markup your HTML with RDFa• Use standard vocabularies (ontologies)

– Google Vocabulary– Good Relations– Dublin Core

• Google and Yahoo will crawl this data and use it for better rendering

On-the-fly Mashups

http://sig.ma

Domain Specific Applications

Domain Specific Applications

• Government– Data.gov– Data.gov.uk– http://data-gov.tw.rpi.edu/wiki/Demos

• Music– Seevl.net

• Dbpedia Mobile• Life Science

– LinkedLifeData• Sports

– BBC World Cup

Faceted Browsers

http://dbpedia.neofonie.de/browse/

Query your data

Find all the locations of all the original paintings of Modigliani

Select all proteins that are linked to a curated interaction from the literature and to inflammatory response

http://linkedlifedata.com/

http://tata.csres.utexas.edu:8080/specify/data/taxon51807


Links to other Data Sources

Linked Data is Data Integration

Specify

Morphbank

Morphster

SPARQLQuery

Diamond

Ultrawrap

Ultrawrap

Ultrawrap

Example 1 (Specify – DBpedia)

• Get full name and guid from taxon with id http://tata.csres.utexas.edu:8080/specify/data/taxon51807#thing

• AND fin any subjects it may have “skos:subject”

http://tata.csres.utexas.edu:8080/specify/data/taxon51807%23thing


Result Example 1• Note that

http://dbpedia.org/resource/Category:Fish_of_Australia comes from a different data source (dbpedia.org)

http://dbpedia.org/resource/Category:Fish_of_Australia

http://dbpedia.org/resource/Category:Fish_of_Australia

Example 2 (Specify-Morphbank)

• Get full name and guid from taxon with id http://tata.csres.utexas.edu:8080/specify/data/taxon42947#thing

• AND the rank and kingdom from Morphbank



Result Example 2• Note that full name and guid come

from Specify http://tata.csres.utexas.edu:8080/specify/data/taxon42947

• AND rank and kingdom come from Morphbank http://tata.csres.utexas.edu:8080/morphbank/data/taxa398354



http://tata.csres.utexas.edu:8080/morphbank/data/taxa398354

http://tata.csres.utexas.edu:8080/morphbank/data/taxa398354

The killer app for Semantic Technology is YOUR life (online)

– Tom Gruber

A little semantics goes a long way

- Jim HendlerKnowledge is Power

- Jim Hendler

The novel part of the Semantic Web is not the Semantics, but the Web

- Frank van Harmelen

Occupy Your Data- Tim Finin

RAW DATA NOW- Tim Berners-Lee

Linked Data is the (Semantic) Web done right

- Tim Berners-Lee

QUESTIONS?