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Chapter Copyright 2008 Digital Enterprise Research Institute. All rights reserved.
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The Social Semantic Weband
Linked Data
DM110 Emerging Web Media10th November 2008
Alexandre Passant <[email protected]>Digital Enterprise Research Institute, National University of Ireland, Galway
Digital Enterprise Research Institute www.deri.ie
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
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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 ?
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So may social media sites ...
* Source: Smashcut Media, www.smashcut-media.com
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So may social media sites ...
* Source: Smashcut Media, www.smashcut-media.com
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Even more services…
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Even more services…
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It takes a lot of time…
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It takes a lot of time…
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Filling out profiles, re-adding your friends…
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Filling out profiles, re-adding your friends…
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Uploading content to “stovepipes”!
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Uploading content to “stovepipes”!
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Social media sites are like data silos
* Source: Pidgin Technologies, www.pidgintech.com
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Many isolated communities of users and their data
* Source: Pidgin Technologies, www.pidgintech.com
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Need ways to connect these islands
* Source: Pidgin Technologies, www.pidgintech.com
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Allowing users to easily move from one to another
* Source: Pidgin Technologies, www.pidgintech.com
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Enabling users to easily bring their data with them
* Source: Pidgin Technologies, www.pidgintech.com
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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)
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Social Semantic Information Spaces
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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
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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 “[email protected]” .
Relationships using the foaf:knows property: :John foaf:knows :Alex
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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
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Integrating social networks w/ FOAF
Source: Sheila Kinsella, Applications of Social Network Analysis 2007
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Integrating social networks w/ FOAF
Source: Sheila Kinsella, Applications of Social Network Analysis 2007
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Integrating social networks w/ FOAF
Source: Sheila Kinsella, Applications of Social Network Analysis 2007
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Integrating social networks w/ FOAF
Source: Sheila Kinsella, Applications of Social Network Analysis 2007
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Integrating social networks w/ FOAF
Common formats,unique URIsSource: Sheila Kinsella, Applications of Social Network Analysis 2007
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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–
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Unifying Web 2.0 networks
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Unifying Web 2.0 networks
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Unified queries
Using SPARQL No matter where the data comes from, as soon as it is
exported via FOAF in RDF SELECT ?f1 ?f2
WHERE {
?f1 foaf:knows ?f2 .
} {Alice, Bob} {Bob, Alex} {Alex, Bob}
:Alice
:Alex
:Bob
foaf:knows
foaf:knows
foaf:knows
:Bill
foaf:name
Alice
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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
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Unifying networks
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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/
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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/
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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
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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/
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The SIOC food chain
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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/
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The SIOC Ontology
Sample export of SIOC data from vBulletin
Sample export of SIOC data from vBulletin
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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
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A person and their user accounts
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FOAF + SIOC = Data Portability
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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 .
}
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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
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Microblogging with SIOC
SMOB - Semantic Microblogging service http://smob.sioc-project.org Publishing and browsing SIOC data
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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
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SIOC Adoption
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SIOC Adoption
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SIOC Adoption
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SIOC Adoption
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SIOC Adoption
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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
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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
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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
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Browsing Linked Data
Client-side Tabulator (FF plug-in)
Server-side Disco, Marbles ...
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The LOD cloud
http://richard.cyganiak.de/2007/10/lod/
http://richard.cyganiak.de/2007/10/lod/
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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
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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
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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
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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
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DBPedia example
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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/
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People born in Galway
Simple triple pattern <http://dbpedia.org/ontology/Person#birthPlace>
?who
:Galway
<http://dbpedia.org/ontology/Person#birthPlace>
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People born in Galway
Simple triple pattern <http://dbpedia.org/ontology/Person#birthPlace>
Answer SELECT ?who
WHERE {
?who <http://dbpedia.org/ontology/Person#birthPlace> :Galway .
}
?who
:Galway
<http://dbpedia.org/ontology/Person#birthPlace>
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Japanese name of Galway
Using the FILTER by LANG clause FILTER(lang(?x) = “ja”)
:Galway
rdfs:label
"Galway"@en
rdfs:label
"ゴールウェイ"@ja
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Japanese name of Galway
Using the FILTER by LANG clause FILTER(lang(?x) = “ja”)
Answer SELECT ?name
WHERE {
:Galway rdfs:label ?name .
FILTER (lang(?name) = “ja”) .
}
:Galway
rdfs:label
"Galway"@en
rdfs:label
"ゴールウェイ"@ja
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10 first cities in the same county
Combining triples patterns ORDER BY and LIMIT
ORDER BY ASC(?x) LIMIT X
:Galway
?county
dbpedia2:county
foaf:name
"Galway"@e
?city dbpedia2:county
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10 first cities in the same county
Combining triples patterns ORDER BY and LIMIT
ORDER BY ASC(?x) LIMIT X
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
:Galway
?county
dbpedia2:county
foaf:name
"Galway"@e
?city dbpedia2:county
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Irish cities on the East of Galway
FILTER by type and comparison of coordinates
:Galway
geo:long
rdf:type
-9.041800
?city
geo:long
-6.266111
yago:CitiesInTheRepublicOfIreland
rdf:type
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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)
}
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Score of games played in Galway
With OPTIONAL current team of scorers ! OPTIONAL {?s ?p ?o}
?gamedbpedia2:score
dbpedia2:stadium
1-1 ?scorer
dbpedia2:currentclub
:Galway
dbpedia2:goals
?currentclub
?game
dbpedia2:score
2-1
dbpedia2:stadium
dbpedia2:stadium
?game
This one has no score !!
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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
}
}
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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
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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
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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