DERI Social Semantic Web and Linked Data

Digital Enterprise Research Institute www.deri.ie

The Social Semantic Web
and
Linked Data
Alexandre Passant <alexandre.passant@deri.org>
Digital Enterprise Research Institute,
National University of Ireland, Galway

DM110 Emerging Web Media
10th November 2008

 Copyright 2008 Digital Enterprise Research Institute. All rights reserved.
Chapter

Agenda

 Issues of Web 2.0 websites
 Data portability, lack of semantics ...
 Social network fatigue
 The Social Semantic Web
 FOAF, SIOC
 Exporting Data, unifying identities ...
 Linked Data
 The Linking Open Data initiative
 DBpedia
 Queries examples (hands on)
 Conclusion
 And references

Web 2.0: What if I want to ...

 Move my content from one place to another ?
 RSS ? Not enough
 Aggregate my data
 An open FriendFeed ?
 Re-use my Flickr friends on Twitter ?
 Invite. Again and again ...

 The Semantic Web can help !
 By providing a common framework to interlink data from
various providers in an open way
 But what about Web economy ?

So may social media sites ...

* Source: Smashcut Media, www.smashcut-media.com

Even more services…

It takes a lot of time…

Filling out profiles, re-adding your
friends…

Uploading content to “stovepipes”!

Social media sites are like data silos

* Source: Pidgin Technologies, www.pidgintech.com

Many isolated communities of
users and their data


Need ways to connect these islands


Allowing users to easily move from
one to another


Enabling users to easily bring
their data with them


Solving the issues

 Social Network Fatigue
 “People are getting sick of registering and re-declaring their friends
on every site” Brad Fitzpatrick (Aug. 2007)
 The Social Semantic Web
 Combining Web 2.0 and the Semantic Web
 Enabling a distributed graph of people, networks and content
 “I think we could have both Semantic Web technology
supporting online communities, but at the same time also online
communities can support Semantic Web data by being the
sources of people voluntarily connecting things together.” Tim
Berners-Lee (ISWC2005 podcast)

Social Semantic Information Spaces

Introducing FOAF and SIOC

 Describing people and their relationships
 FOAF - Friend Of A FRiend
 http://foaf-project.org
 Describing Social Media Contributions (CMS)
 SIOC - Semantically-Interlinked Online Communities
 http://sioc-project.org
 FOAF and SIOC are strongly related
 Interlinking both to represent the complete online activity of
one person
 More details later

Modeling people with FOAF

 FOAF is the main vocabulary used to represent people
 Friend Of A Friend - http://foaf-project.org
 foaf:Person class:
 “The foaf:Person class represents people. Something is a
foaf:Person if it is a person.”
 Give yourself a URI
 http://apassant.net/alex
 Various properties to model your identity
 :Alex rdf:type foaf:Person ;
foaf:name “Alexandre Passant” ;
foaf:mbox “alex@passant.org” .
 Relationships using the foaf:knows property:
 :John foaf:knows :Alex

Extending relationships

 foaf:knows is voluntary broad
 No difference between friends, collegues, family members ...
 The RELATIONSHIP vocabulary
 http://vocab.org/relationship/
 More than 30 different kinds of relationships
 :John rel:worksWith :Alex .
 :Alice rel:engagedTo :Bob .
 All rel:* properties are subproperties of foaf:knows
 RDFS inferencing allows tools to answer queries using
foaf:knows when people use rel:* alternatives

Integrating social networks w/ FOAF

Source: Sheila Kinsella, Applications of Social Network Analysis 2007

Integrating social networks w/ FOAF

Common formats,
Source: Sheila Kinsella, Applications of Social Network Analysis 2007 unique URIs

FOAF from existing data

 Existing FOAF exporters for major Web 2.0 services
 Flickr, Facebook, Twitter ...
– http://apassant.net/home/2007/12/flickrdf/
– http://www.dcs.shef.ac.uk/~mrowe/foafgenerator.html
– http://tools.opiumfield.com/twitter/username
–

Unifying Web 2.0 networks

Unified queries

 Using SPARQL
 No matter where the data comes from, as soon as it is
exported via FOAF in RDF
Alice
 SELECT ?f1 ?f2 foaf:name

WHERE { :Alice

?f1 foaf:knows ?f2 . foaf:knows

} :Bob
 {Alice, Bob}
:Bill foaf:knows
 {Bob, Alex}
 {Alex, Bob} foaf:knows

:Alex

Distributed identity management

 A need to unify URIs from different services so as
to represent one's unified identity
 Unifying aspects of a foaf:Person across networks:
 Linked-data principles : owl:sameAs + rdfs:seeAlso:
 owl:sameAs: Used to identify two resources with different
URIs as being the same resource
– :alex owlSameAs flickr:33669349@N00 .
 rdfs:seeAlso: “More information about this resource can be
found here”, can be used by Semantic Web browsers
 Inference using owl:InverseFunctionalProperty:
 foaf:mbox, foaf:openid, etc. can be used to identify
uniqueness for a foaf:Person

Unifying networks

Browsing FOAF data

 FOAFnaut, FOAF Explorer, FOAFmap, etc ...
 FOAFGear: thanks to common semantics, only 100
lines of code: http://apassant.net/home/2008/01/
foafgear/

More tools and services

 Browse / re-use your social graph in personal
applications
 Tools:
 Beatnik - https://sommer.dev.java.net/AddressBook.html
 Knowee - http://knowee.org
 SPARQLpress - http://wiki.foaf-project.org/SparqlPress
 Nepomuk - http://nepomuk.semanticdesktop.org/



Social Media Contributions

 Lots of user-created content posted on the Web:
 Blog posts, wiki pages, bulletin board threads
 Called « Social Media Contributions » or SMC
 Distributed content
 Blogging platform, photos-sharing website, social
bookmarking service ….
 A need for common semantics to
 Provide a single model for any SMC, wherever it comes
from
 Enables the use of SPARQL queries instead of proprietary
APIs
 Interlink data and find relationships between content
 From documents to resources, from WWW to GGG

Modeling SMC on the Semantic Web

 SIOC - Semantically Interlinked Online Communities
 http://sioc-project.org
 A ontology to represent the activities of online
communities on the Web
 More than 40 applications, mainly open-source
 W3C Member Submission, June 2007
 http://www.w3.org/Submission/2007/02/

The SIOC food chain

The SIOC Ontology

 Namespace - http://rdfs.org/sioc/ns
 Five top-level classes: User / Role / Space / Container /
Item
 A “SIOC Types” module for Social Web content
 http://rdfs.org/sioc/types
 Actions: A user posts an item in a container
 :Alex sioc:creator_of <http://example.org/blogpost> .
 A Semantic Web citizen:
 Reusing and interlinking existing ontologies
 Not reinventing the wheel (connects to DC, FOAF, etc.):
 http://www.w3.org/Submission/2007/SUBM-sioc-related-20070612/

The SIOC Ontology

Sample export of SIOC data from
vBulletin

Connecting people and accounts

 The sioc:User class:
 Can be thought of as a virtual representation of any
person online, within the context of a given social media
website or community
 A subclass of foaf:OnlineAccount
 foaf:holdsAccount property:
 “The foaf:holdsAccount property relates a foaf:Agent to a
foaf:OnlineAccount for which they are the sole account
holder.”
 Links a foaf:Person to various sioc:User(s)
 As many sioc:User(s) as required can be linked to a single
person
 One people, various identities

A person and their user accounts

FOAF + SIOC = Data Portability

Querying SMC

 Find all content created by someone with a given
OpenID URL:
 Browse someone’s social media contributions posted on
various websites using different account names, but for
the same person
 A single SPARQL query, no need to play with different APIs

SELECT ?item
WHERE {
?person foaf:openid <$openid> ;
foaf:holdsAccount ?user .
?user sioc:creator_of ?item .
}


Moving data using SIOC

 WordPress SIOC import plug-in
 http://sioc-project.org/wordpress
 Can read any SIOC RDF data and imports it into WordPress
as a native blog post

Microblogging with SIOC

 SMOB - Semantic Microblogging service
 http://smob.sioc-project.org
 Publishing and browsing SIOC data

SIOC : More than Web 2.0

 SWAN
 Semantic Web Applications in Neuromedicine
 http://swan.mindinformatics.org
 Recent efforts to align SIOC and SWAN
 Scientific Discourse representation
 W3C HCLS Interest Group
 http://esw.w3.org/topic/HCLSIG/SWANSIOC
 Ontologies alignment to provide a complete
framework to model activities of scientific
communities
 SIOC to model the online content
 SWAN to model the discourse

SIOC Adoption

Linked Data

 The Linking Open Data initiative
 Community effort
 http://linkeddata.org
 Lots of information available on the Web
 Closed world, proprietary data silos
 Provide it in RDF and interlink it !
 The Web as a giant database
 From documents to machine-understandable data
 Use links to discover data by browsing the GGG
 Open licensing policy
 ISWC2008 tutorial on Linked Data

The 4 principles of Linked Data

 Tim Berners-Lee, 2006
 http://www.w3.org/DesignIssues/LinkedData.html

 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.
 Include links to other URIs. so that they can
discover more things.
 Using the rdfs:seeAlso property

URIs and Linked Data

 Cool URIs for the Semantic Web
 http://www.w3.org/TR/2007/WD-cooluris-20071217
 A person is not a webpage !
 http://apassant.net/alex != http://apassant.net/about

Browsing Linked Data

 Client-side
 Tabulator (FF plug-in)
 Server-side
 Disco, Marbles ...

The LOD cloud

http://richard.cyganiak.de/2007/10/lod/

http://richard.cyganiak.de/2007/10/lod/

LOD example: music-related data

 http://dbtune.org
 Music-related RDF platform
 LOD-exporters for major music databases and
social services
 MusicBrainz, Jamendo
 Last.fm, MySpace
 Interlinked with references datasets
 Geonames, DBPedia, riese, FOAF
 Advanced querying and browsing features

LOD: Semantic Mash-ups

 Bands + locations = dbtune + geonames
 http://blog.dbtune.org/post/2008/02/06/Playing-with-
Linked-Data-Jamendo-Geonames-Mazzle-and-Songbird

DBpedia

 http://dbpedia.org
 Provide RDF representation of data extracted from
DBpedia
 More that 2 million concepts (people, places, ...)
 Internationalization
 Interlinking from and to DBpedia
 Interlinked with other datasets (Geonames, DBLP ...)
 Can be used in FOAF profiles
– :Alex foaf:topic_interest dbpedia:Semantic_Web

DBpedia URI scheme

 Resource URI
 http://dbpedia.org/resource/Semantic_Web
 Redirects to its HTML or RDF representation depending on
the user-agent
 HTML Document
 http://dbpedia.org/page/Semantic_Web
 RDF Data
 http://dbpedia.org/data/Semantic_Web

DBPedia example

Querying DBpedia

 Hands-on session !
 Different kind of queries
 Going deeper in SPARQL (FILTER, OPTIONAL ...)
 Will be useful for next assignment
 DBpedia provides a SPARQL endpoint
 http://dbpedia.org/sparql
 User interface using SNORQL
 Pre-defined prefixes, AJAX-rendering ...
 http://dbpedia.org/snorql/

People born in Galway

 Simple triple pattern
 <http://dbpedia.org/ontology/Person#birthPlace>

?who

<http://dbpedia.org/ontology/Person#birthPlace>

:Galway

People born in Galway

 Simple triple pattern
 <http://dbpedia.org/ontology/Person#birthPlace>

?who

<http://dbpedia.org/ontology/Person#birthPlace>
 Answer
 SELECT ?who :Galway

WHERE {
?who <http://dbpedia.org/ontology/
Person#birthPlace> :Galway .
}

Japanese name of Galway

 Using the FILTER by LANG clause
 FILTER(lang(?x) = “ja”)
quot;Galwayquot;@en

rdfs:label

:Galway
rdfs:label
quot; quot;@ja

Japanese name of Galway

 Using the FILTER by LANG clause
 FILTER(lang(?x) = “ja”)
quot;Galwayquot;@en

rdfs:label

:Galway
 Answer rdfs:label
quot; quot;@ja
 SELECT ?name
WHERE {
:Galway rdfs:label ?name .
FILTER (lang(?name) = “ja”) .
}

10 first cities in the same county

 Combining triples patterns quot;Galwayquot;@e
foaf:name
 ORDER BY and LIMIT :Galway
 ORDER BY ASC(?x) dbpedia2:county
 LIMIT X
?city dbpedia2:county ?county

10 first cities in the same county

 Combining triples patterns quot;Galwayquot;@e
foaf:name
 ORDER BY and LIMIT :Galway
 ORDER BY ASC(?x) dbpedia2:county
 LIMIT X
?city dbpedia2:county ?county
 Answer
 SELECT ?city ?name
WHERE {
:Galway dbpedia2:county ?county .
?city dbpedia2:county ?county ;
rdfs:label ?name .
FILTER(lang(?name) = “en”) .
} ORDER BY ASC (?name) LIMIT 10

Irish cities on the East of Galway

 FILTER by type and comparison of coordinates

?city

-9.041800
geo:long
geo:long
:Galway
rdf:type

rdf:type -6.266111

yago:CitiesInTheRepublicOfIreland

Irish cities on the East of Galway

 FILTER by type and comparison of coordinates
 Answer
 PREFIX geo: <http://www.w3.org/2003/01/geo/
wgs84_pos#>
PREFIX yago: <http://dbpedia.org/class/yago/>
SELECT DISTINCT ?place ?long WHERE {
:Galway geo:long ?glong .
?place rdf:type
yago:CitiesInTheRepublicOfIreland ;
geo:long ?long ;
FILTER (?long > ?glong)
}

Score of games played in Galway

 With OPTIONAL current team of scorers !
 OPTIONAL {?s ?p ?o}

1-1 dbpedia2:score ?game dbpedia2:goals ?scorer

dbpedia2:stadium

dbpedia2:currentclub

:Galway
2-1

dbpedia2:stadium
?currentclub
dbpedia2:score
dbpedia2:stadium

?game
?game
This one has no score !!

Score of games played in Galway

 With OPTIONAL current team of scorers !
 OPTIONAL {?s ?p ?o}
 ANSWER
 SELECT ?game ?score ?scorer ?currentclub
WHERE {
?game dbpedia2:stadium :Galway .
dbpedia2:score ?score .
OPTIONAL {
?game dbpedia2:goals ?scorer .
?scorer dbpedia2:currentclub ?club
}
}

Conclusion

 Social Semantic Web and Linked Data provides lots
of RDF data on the Web
 It’s time to use it !
 Web 3.0 ... or Web 0.1 ?
– Berners-Lee, 1989 !

– http://www.w3.org/History/1989/proposal.html

Upcoming challenges

 Distributed querying
 In order to query different endpoints at the same time
 Privacy and Trust
 What should I deliver ?
 Who should I trust ?
 Temporal querying
 Data evolution
 Reasoning
 Derive new facts from existing ones

References

 Some slides based on material from:
 SAW2008 - Social Network and Data Portability using
Semantic Web Technologies (pdf - slides)
 SDoW2008 - Combining Social Music and Semantic Web for
music-related recommender systems (pdf - slides)
 Additional references
 Social Data on the Web 2008 workshop
– http://sdow2008.semanticweb.org
 Linked Data on the Web 2008 workshop
– http://events.linkeddata.org/ldow2008/
 W3C SPARQL Tutorial
– http://www.w3.org/TR/rdf-sparql-query
 + Tutorials referenced on the previous lecture

DERI Social Semantic Web and Linked Data

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