A rule-based approach for the real-time semantic annotation in context-aware ...
VisAVis: An Approach to an Intermediate Layer between Ontologies and Relational Database Contents
1. VisAVis: An Approach to anVisAVis: An Approach to an
Intermediate Layer between OntologiesIntermediate Layer between Ontologies
and Relational Database Contentsand Relational Database Contents
Nikolaos Konstantinou, NationalNikolaos Konstantinou, National
Technical University of GreeceTechnical University of Greece
2. Web Information Systems Modeling Luxembourg, June2
IntroductionIntroduction
VisAVis ProtVisAVis Protééggéé PluginPlugin
FeaturesFeatures
– Map between RDB and OntologiesMap between RDB and Ontologies
– Execute queries expressed in RDQLExecute queries expressed in RDQL
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MotivationMotivation
The Semantic Web Vision orders thatThe Semantic Web Vision orders that
web pages need to be annotated inweb pages need to be annotated in
terms of an ontology languageterms of an ontology language
What happens with Data stored inWhat happens with Data stored in
databases and is generated anddatabases and is generated and
retrieved automatically?retrieved automatically?
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DefinitionsDefinitions
An Ontology can be defined as a modelAn Ontology can be defined as a model
of a Knowledge Baseof a Knowledge Base
Thus, we have the Terminological andThus, we have the Terminological and
the Assertional Box (ABox & TBox)the Assertional Box (ABox & TBox)
Simplified point of view:Simplified point of view:
– TBox <-> Schema of the RDBTBox <-> Schema of the RDB
– ABox <-> Instance of the actual dataABox <-> Instance of the actual data
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Mapping ProcessMapping Process
Capture Database DataCapture Database Data
Select an Ontology ClassSelect an Ontology Class
Validate the mappingValidate the mapping
Modify the resulting OntologyModify the resulting Ontology
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Mapping ProcessMapping Process
Validate the mappingValidate the mapping
– Disjoint classes cannot have mappings toDisjoint classes cannot have mappings to
common data. Common data includescommon data. Common data includes
data in tables with a foreign key relationdata in tables with a foreign key relation
– Maintain subclass hierarchy in theMaintain subclass hierarchy in the
databasedatabase
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Query ExecutionQuery Execution
Parse requestsParse requests
Instead of returning the classInstead of returning the class
resources, we check if the mappingresources, we check if the mapping
property existsproperty exists
– Yes: redirect the query to the databaseYes: redirect the query to the database
– No: No changesNo: No changes
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Use-Case ScenarioUse-Case Scenario
<owl:Class rdf:about="#Hiking">
<queryString>SELECT activities.description FROM
activities, activities_types WHERE
(activities.activity_type_id = activities_types.id) AND
(activities_types.name = "Hiking")
</queryString>
<rdfs:subClassOf>
<owl:Class rdf:about="#Sports"/>
</rdfs:subClassOf>
</owl:Class>
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ImplementationImplementation
Java, version 1.5.0 or higherJava, version 1.5.0 or higher
Jena framework, tested in versions 2.2Jena framework, tested in versions 2.2
and 2.3and 2.3
ProtProtééggé, tested in 3.0, 3.1, 3.1.1,é, tested in 3.0, 3.1, 3.1.1,
3.2beta3.2beta
MySQL and PostgreSQL, with JDBCMySQL and PostgreSQL, with JDBC
connectionconnection
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Future WorkFuture Work
Richer SQL builderRicher SQL builder
Support for more databasesSupport for more databases
Return results from both the databaseReturn results from both the database
and the ontologyand the ontology
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QuestionsQuestions
Thank you for your attentionThank you for your attention
VisAVis plugin available atVisAVis plugin available at
http://www.cn.ntua.gr/~nkons/essays_en.htmlhttp://www.cn.ntua.gr/~nkons/essays_en.html