Using the Semantic Web, and Contributing to it
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Transcript of Using the Semantic Web, and Contributing to it
Using the Semantic Web,and Contributing to it
Mathieu d’Aquin KMi, The Open University – [email protected]
Semantic Web
A large scale, heterogenous collection of formal, machine processable, ontology-based statements (semantic metadata) about web resources and other entities in the world, expressed in a XML-based syntax
<rdf:RDF> <owl:Ontology rdf:about=""> <owl:imports rdf:resource="http://usefulinc.com/ns/doap#"/> </owl:Ontology> <j.1:Organization rdf:ID="KMi"> <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string" >The Knoledge Media Institute of the Open University, Milton Keynes UK</rdfs:comment> </j.1:Organization> <j.1:Document rdf:ID="KMiWebSite"> …
<rdf:RDF> <owl:Ontology rdf:about=""> <owl:imports rdf:resource="http://usefulinc.com/ns/doap#"/> </owl:Ontology> <j.1:Organization rdf:ID="KMi"> <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string" >The Knoledge Media Institute of the Open University, Milton Keynes UK</rdfs:comment> </j.1:Organization> <j.1:Document rdf:ID="KMiWebSite"> … <rdf:RDF>
<channel rdf:about=“http://watson.kmi.open.ac.uk/blog”><title>Elementaries - The Watson Blog</title><link>http://watson.kmi.open.ac.uk:8080/blog/</link><description>"Oh dear! Where the Semantic Web is going to go now?" -- imaginary user 23</description><language>en</language><copyright>Watson team</copyright><lastBuildDate>Thu, 01 Mar 2007 13:49:52 GMT</lastBuildDate><generator>Pebble (http://pebble.sourceforge.net)</generator><docs>http://backend.userland.com/rss</docs>…
<rdf:RDF><channel rdf:about=“http://watson.kmi.open.ac.uk/blog”><title>Elementaries - The Watson Blog</title><link>http://watson.kmi.open.ac.uk:8080/blog/</link><description>"Oh dear! Where the Semantic Web is going to go now?" -- imaginary user 23</description><language>en</language><copyright>Watson team</copyright><lastBuildDate>Thu, 01 Mar 2007 13:49:52 GMT</lastBuildDate><generator>Pebble (http://pebble.sourceforge.net)</generator><docs>http://backend.userland.com/rss</docs>…
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<rdf:RDF><channel rdf:about=“http://watson.kmi.open.ac.uk/blog”><title>Elementaries - The Watson Blog</title><link>http://watson.kmi.open.ac.uk:8080/blog/</link><description>"Oh dear! Where the Semantic Web is going to go now?" -- imaginary user 23</description><language>en</language><copyright>Watson team</copyright><lastBuildDate>Thu, 01 Mar 2007 13:49:52 GMT</lastBuildDate><generator>Pebble (http://pebble.sourceforge.net)</generator><docs>http://backend.userland.com/rss</docs>…
<rdf:RDF><channel rdf:about=“http://watson.kmi.open.ac.uk/blog”><title>Elementaries - The Watson Blog</title><link>http://watson.kmi.open.ac.uk:8080/blog/</link><description>"Oh dear! Where the Semantic Web is going to go now?" -- imaginary user 23</description><language>en</language><copyright>Watson team</copyright><lastBuildDate>Thu, 01 Mar 2007 13:49:52 GMT</lastBuildDate><generator>Pebble (http://pebble.sourceforge.net)</generator><docs>http://backend.userland.com/rss</docs>…
<rdf:RDF> <foaf:Image rdf:about='http://static.flickr.com/132/400582453_e1e1f8602c.jpg'> <dc:title>Zen wisteria</dc:title> <dc:description></dc:description> <foaf:page rdf:resource='http://www.flickr.com/photos/xcv/400582453/'/> <foaf:topic rdf:resource='http://www.flickr.com/photos/tags/vittelgarden/'/> <foaf:topic rdf:resource='http://www.flickr.com/photos/tags/wisteria/'/> <dc:creator> <foaf:Person><foaf:name>Mathieu d'Aquin</foaf:name> …
<rdf:RDF> <foaf:Image rdf:about='http://static.flickr.com/132/400582453_e1e1f8602c.jpg'> <dc:title>Zen wisteria</dc:title> <dc:description></dc:description> <foaf:page rdf:resource='http://www.flickr.com/photos/xcv/400582453/'/> <foaf:topic rdf:resource='http://www.flickr.com/photos/tags/vittelgarden/'/> <foaf:topic rdf:resource='http://www.flickr.com/photos/tags/wisteria/'/> <dc:creator> <foaf:Person><foaf:name>Mathieu d'Aquin</foaf:name> …
<rdf:RDF> <owl:Ontology rdf:about=""> <owl:imports rdf:resource="http://usefulinc.com/ns/doap#"/> </owl:Ontology> <j.1:Organization rdf:ID="KMi"> <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string" >The Knoledge Media Institute of the Open University, Milton Keynes UK</rdfs:comment> </j.1:Organization> <j.1:Document rdf:ID="KMiWebSite"> …
<rdf:RDF> <owl:Ontology rdf:about=""> <owl:imports rdf:resource="http://usefulinc.com/ns/doap#"/> </owl:Ontology> <j.1:Organization rdf:ID="KMi"> <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string" >The Knoledge Media Institute of the Open University, Milton Keynes UK</rdfs:comment> </j.1:Organization> <j.1:Document rdf:ID="KMiWebSite"> …
FOAF
DCRSS TAP
WORDNET
NCI Galen
Music
…… …
…
…
OK, nice… but what’s the reality?
2007 2008 2009
So, Using the Semantic Web?• Many research and development efforts in
– Supporting the design of ontologies (methodologies, toolkits, editors, etc.)
– Supporting the annotation Web resources (natural language processing, information extraction, etc.)
– Supporting the publication of semantic data and information online (linking open data, `semantification’ of legacy information systems
– …
• Resulting in an explosion of the amount of machine processable knowledge online.
• Now the question is: What to do with it? How to exploit it? What are the missing infrastructure components necessary to develop Semantic Web application?
Next Generation Semantic Web Applications
NG SW Application Semantic WebSmart Features
Able to exploit the SW at large
– Dynamically retrieving the relevant semantic resources
– Combining several, heterogeneous Ontologies
Next Generation Semantic Web Applications
Dynamically retrieving, exploiting and combining relevant semantic resources from the SW, at large
Need for a Gateway to the Semantic Web
Watson: a Gateway to the Semantic Web
Architecture
Interface
http://watson.kmi.open.ac.uk
But the important part is: the APIs
• Provide Semantic Web application developers with the ability to efficiently:
– Locate (find) Semantic Web documents online using advanced search functions
– Explore the documents, automatically extracted metadata and content
– Query the documents, to exploit online knowledge in an homogeneous way
• In a set of lightweight APIs, and without having to download the data or use any other dedicated infrastructure.
Some Applications We Developed
Ontology Reuse:The Watson Plugin
Question Answering:PowerAqua
Semantic Browsing:PowerMagpie
Semantic Relation Discovery:Scarlet
Folksonomy Enrichment
And also:Word sense disambiguationQuery ExpansionSynonym Discovery…
Example: The Watson Plugin
Chose an entity to search
Get entities from online ontologies
Integrate statements Into the edited ontology
Example: Scarlet
ka2.rdf
Researcher AcademicStaff
Sem
anti
c W
eb
Researcher
AcademicStaff
⊆
⊆
ISWC SWRCHam SeaFood
Sem
anti
c W
eb
HamSeaFood
Meat
Meat
SeaFood
Agrovoc NALT
⊆
€
⊥
€
⊥
€
⊥
pizza-to-go
wine.owl
NALT
Example: Scarlet
Example: PowerAqua
Natural language question
Answers from online semantic data
Example: FLOR
Can the Semantic Web provide the structure needed to improve search and navigation of tagged spaces?
Search in Tag Spaces
5/24 ≈ 21% relevant
Dog Dog
DogDog
Bird
Bird
Bird
Bird
Bird
Bird
Bird
Tiger
Tiger
Tiger
Tiger
CatLandscape
Landscape
Landscape
Let’s find photos of “animals which live in the water”
Query: Animal Water
Bring in the SW…
Dolphin
Seal
Marine Mammal
Mammal
Sea
livesIn
Whale
Body of Water
Ocean
Sea Elephant
FishlivesIn
Animal
FreshwaterFish
SaltwaterFish
livesIn
Animal Water
<Animal livesIn Water>
<Dolphin>or<Seal>or<“Sea Elephant”>or<Whale>
Results
dolphin
seal
whale
sea elephant
18/24 ≈ 75% relevant
Other Use of Watson/the Semantic Web:Understanding Knowledge Online
Number of entities
Domain covered
Underlying description logic
Other Use of Watson/the Semantic Web:Understanding Knowledge Online
• Looking at relationships between ontologies:
– Inclusion, equivalence: can ontologies being syntactically different, or even represented in different languages represent the same formal model?
– Similarity: How close are two ontologies? How to define similarity between ontologies in particular context?
– Versioning: How to detect if an ontology is a different version from another one? Which on came first? Which is the latest? How to characterize the changes (at syntactic level, at model level)?
– Agreement/Disagreement: How to measure that two ontologies contradict each other? Agree on certain points? Are logical inconsistency/incoherence enough?
• A complete framework based on an ontology formalizing relations between ontologies to detect and reason upon relationships between ontologies in Watson
• Looking at relationships between ontologies:
– Inclusion, equivalence: can ontologies being syntactically different, or even represented in different languages represent the same formal model?
– Similarity: How close are two ontologies? How to define similarity between ontologies in particular context?
– Versioning: How to detect if an ontology is a different version from another one? Which on came first? Which is the latest? How to characterize the changes (at syntactic level, at model level)?
– Agreement/Disagreement: How to measure that two ontologies contradict each other? Agree on certain points? Are logical inconsistency/incoherence enough?
• A complete framework based on an ontology formalizing relations between ontologies to detect and reason upon relationships between ontologies in Watson
Other Use of Watson/the Semantic Web:Agreement/Disagreement in Ontologies
• Ontologies are knowledge artifacts, they express opinions, beliefs
• As such they can differ, contradict each others
• Assessing (dis)agreement in ontologies is very useful to understand how to combine knowledge from different sources
• A possible approach would be to check whether inconsistencies and incoherencies appear while combining the ontologies. However we believe that:
– There are di erent levels of agreement/disagreement ff
– Covering di erent domains is not agreeing ff
– It is possible to agree and disagree at the same time
• Based on these requirements we define a set of measures for assessing (dis)agreement between statements and ontologies.
Other Use of Watson/the Semantic Web:Agreement/Disagreement in Ontologies
• Agreement(st, O) [0..1] and Disagreement(st, O) [0..1] where st is a statement <subject, predicate, object> and O is an ontology
• Based on extracting the part of the ontology that express a relation between subject and object
• (Dis)agreement between ontologies:
• Global (dis)agreement in a repository
• Consensus:
• Controversy:
Other Use of Watson/the Semantic Web:Agreement/Disagreement in Ontologies
• Experiment: assessing statements related to the class Seafood in Watson:
a: global agreement, d: global disagreement, cs: consensus, ct: controversy
• More experiments on the Way!
Contributing to the Semantic Web
• So, using the Semantic Web is all about exploiting what is made available online, as distributed, heterogeneous knowledge in ontologies
• Our ability to do that therefore depends on the availability of ontologies, semantic information and machine processable data.
• More precisely on the availability of quality knowledge on the Semantic Web
• And incidentally on the availability of quality information about ontologies
Slide 27
From a Semantic Web search engine…
Slide 28
… to Ontology Repositories?
Ontologies
Ontology Metadata
Versions of
Alignments
Comments and
Reviews
Cupboard
Using the User?
• How ontologies are used and reused in applications and other ontologies can also provide interesting information about these ontologies, i.e. contributions in the form of quality information
• We develop a trust engine which can collect positive or negative evaluations for ontology statements, from various users and applications, to propagate this information for ranking ontology entities.
• Application to the Watson plugin.
Automatic evaluation of statements through a trust engine
Watson Trust Service
Trust Propagation
YouClick Here
This statementis goodRanking for
statements/entities
Example - Evaluation as a Side Effect
Example - Ranking According to Trust
Example - Propagation
Final message
• I hope I convinced you that
Using the Semantic Web Contributing to the Semantic Web
• Through Watson, Cupboard and our applications, our aim is to build an open and efficient platform making the Semantic Web a `playground for research and development’
• There is still a lot to do, and everybody is welcome to comment, help, contribute…
Thank You!
Mathieu d’Aquin ([email protected], http://people.kmi.open.ac.uk/mathieu) With contributions from many people in Kmi (http://kmi.open.ac.uk) and the NeOn project (http://neon-project.org)
/* I would normally include a bibliography slide at the end, but all the relevant papers can be found on these 3 websites */