WTF is the Semantic Web and Linked Data

WTF is the Semantic Web and Linked Data Juan F. Sequeda Department of Computer Science University of Texas at Austin Nov 17, 2011

Semantic Web? Linked Data? WTF?

WTF is the Semantic Web?

Internet != Web

What is the Web?“… the Web, is a system ofinterlinked hypertext documentsaccessed via the Internet. With aweb browser, one can view webpages that may contain text,images […] and navigate betweenthem 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 SearchSearchEngineCrawler

The Web is a Data ShredderStructured Unstructured Data 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 theUniversity 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 differentformats and data models!

This makes it hard to integrate data

The data in differentdata 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 fromdifferent services, I have to learndifferent APIs and I get different formats of data back

Data is Siloed

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

We have a standardized way ofpublishing documents on the web, right? HTML

Then why can’t we have a standardway 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”

Identifier forthe “group” RDF is a Graph Key/Value• 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 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.org Rich Snippets …

An example

Document on the Web

Databases back up documents THINGS have PROPERTIES: A Book as a Title, an author, …Isbn Title Author PublisherID ReleasedData978-0-596- Programming Toby Segaran 1 July 200915381-6 the Semantic Web… … … … … PublisherID PublisherNameThis is a THING:A book title “Programming the 1 O’Reilly MediaSemantic Web” by Toby Segaran, … … …

Lets represent the data in RDFIsbn Title Author PublisherID ReleasedData978-0- Programming Toby 1 July 2009596- the Semantic Segaran15381- Web6 Programming thePublisherID PublisherName title Semantic Web1 O’Reilly Media author book Toby Segaran isbn 978-0-596-15381-6 publisher name Publisher O’Reilly

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 Programming the title Semantic Web http://…/i author Toby Segaran sbn978 isbn 978-0-596-15381-6 publisher http://…/p name ublisher1 O’Reilly

And now consider the data from Revyu.comhttp://…/ hasReview http://…/i review1 sbn978 descriptionreviewer Awesome Book http://…/ name reviewer Juan Sequeda

Let’s start to link data http://…/ hasReview http://…/i review1 sbn978 Programming the description title Semantic WebhasReviewer owl:sameAs Awesome author http://…/i Book Toby Segaran sbn978 http://…/ name reviewer isbn 978-0-596-15381-6 Juan publisher Sequeda http://…/p name ublisher1 O’Reilly

Juan Sequeda publishes data toohttp://juanse livesIn http://dbpedia.org/Austinqueda.com/id name Juan Sequeda

Let’s link more data http://…/ hasReview http://…/i review1 sbn978 descriptionhasReviewer Awesome Book http://…/ name reviewer sameAs Juan Sequeda http://juanse livesIn http://dbpedia.org/Austin queda.com/id name Juan Sequeda

And more http://…/ hasReview http://…/i review1 sbn978 Programming the description title Semantic WebhasReviewer owl:sameAs Awesome author http://…/i Book Toby Segaran sbn978 http://…/ name reviewer isbn 978-0-596-15381-6 owl:sameAs Juan publisher http://…/p Sequeda name ublisher1 O’Reilly http://juanse livesIn http://dbpedia.org/Austin queda.com/id name Juan Sequeda

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 GIANT HUGE 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 astandardize language for that SPARQL

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

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

SELECT ?review ?comment WHERE { isbn:978 ex:hasReview ?review . ?review ex:description ?comment . http://…/ hasReview ?review ex:hasReviewer ?person . http://…/i review1 ?person ex:lives dbpedia:Austin . sbn978 } Programming the description title Semantic WebhasReviewer sameAs Awesome author http://…/i Book Toby Segaran sbn978 http://…/ name reviewer isbn 978-0-596-15381-6 sameAs Juan publisher Sequeda http://…/p name ublisher1 O’Reilly http://juanse queda.com livesIn http://dbpedia.org/Austin name Juan Sequeda

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…

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#> swrc:Publicatio n rdfs:subClassOf dc:creatorswrc:InProceedings foaf:Person OWL rdf:type owl:sameAs rdf:type auth:Juan_Sequeda sw:juan-f-sequeda dc:creator owl:sameAsdexa:TirmiziSM08 auth:Daniel_P._Miranker sw:daniel-miranker dc:title owl:sameAs auth:Syed_Hamid_Tirmizi sw:syed-tirmizi “Translating SQLApplications to the Semantic Web" RDF

RDB and the Semantic Web TRIGGERS RIF CONSTRAINTS OWLTIME TABLE DEFINITION RDFS RELATIONAL RDF MODEL 74

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

What was your incentive topublish 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 2011Linking Open Datacloud diagram, byRichard Cyganiak andAnja Jentzsch. http://lod-cloud.net/

YOU GET THE PICTUREITS BIG and gettingBIGGER 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

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

Linked Data Browsers• 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

http://tata.csres.utexas.edu:8080/specify/data/taxon51807 Links to other Data Sources

Linked Data is Data Integration SPARQL QueryDiamond Ultrawrap Ultrawrap Specify Ultrawrap Morphster Morphbank

Example 1 (Specify – DBpedia)• Get full name and guid from taxon with id http://tata.csres.utexas.edu:8080/specify/data/t axon51807#thing• AND fin any subjects it may have “skos:subject”

Result Example 1• Note that http://dbpedia.org/resource/Category:Fish_of_ Australia comes from a different data source (dbpedia.org)

Example 2 (Specify-Morphbank)• Get full name and guid from taxon with id http://tata.csres.utexas.edu:8080/specify/data/t axon42947#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/t axon42947• AND rank and kingdom come from Morphbank http://tata.csres.utexas.edu:8080/morphbank/d ata/taxa398354

The killer app for A little semanticsSemantic Technology is goes a long wayYOUR life (online) - Jim Hendler – Tom Gruber Knowledge is Power Occupy Your Data - Jim Hendler - Tim Finin Linked Data is the (Semantic) Web done rightThe novel part of the - Tim Berners-LeeSemantic Web is not theSemantics, but the Web - Frank van Harmelen RAW DATA NOW - Tim Berners-Lee

QUESTIONS?

WTF is the Semantic Web and Linked Data

by Juan Sequeda on Nov 22, 2011

Accessibility

Categories

Upload Details

Usage Rights

Statistics

WTF is the Semantic Web and Linked Data Presentation Transcript