PACIS'03 TU/e eindhoven university of technology July 2003 1 Engineering Semantic Web Information Systems Richard Vdovjak Flavius Frasincar Geert-Jan Houben Peter Barna Databases & Hypermedia Group Department of Computer Science /dept. of mathematics and computer science wwwis.win.tue.nl/~hera
Engineering Semantic Web Information Systems. Richard Vdovjak Flavius Frasincar Geert-Jan Houben Peter Barna. Databases & Hypermedia Group Department of Computer Science. /dept. of mathematics and computer science. wwwis.win.tue.nl/~hera. Overview. - PowerPoint PPT Presentation
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PACIS'03
TU/e eindhoven university of technology
July 2003 1
Engineering Semantic Web Information Systems
Richard Vdovjak
Flavius Frasincar
Geert-Jan Houben
Peter Barna
Databases & Hypermedia Group
Department of Computer Science
/dept. of mathematics and computer science wwwis.win.tue.nl/~hera
PACIS'03
TU/e eindhoven university of technology
July 2003 2
Overview
• Motivating example: Virtual art gallery• Hera framework, models and
• Many to many content delivery • Triggered by the user query • Exhibits (Images) are from (online) Art catalogues• Descriptions are gathered from an (online) Art
Encyclopedia
Virtual art gallery WIS
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TU/e eindhoven university of technology
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We need a framework that offers
• Semantics– Express concepts and their hierarchies
– Relationships among the concepts
– Query language that can exploit the above
• Access to several sources– Flexible source management
– Flexible query mediation
• User/platform adaptation
– (adaptability and adaptivity)
• Automated presentation design– Based on the user query,
– Device profiles and the browsing history
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TU/e eindhoven university of technology
July 2003 5
The Hera Framework: Design Steps, Models, and Processing Engines
• Provides a uniform semantic view over different data sources that are integrated within a given Web application
• Consists of hierarchies of concepts relevant within the given domain, their properties, and relations
• Encoded in RDF(S)
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TU/e eindhoven university of technology
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RDF(S), RQL
• RDF(S)– W3C standard for describing metadata
– Directed labeled graph formalism
– Formal semantics defined
• RQL:select X from {X:Technique}tname{Xtname} where Xtname = "Chiaroscuro"
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TU/e eindhoven university of technology
July 2003 9
Conceptual Model Example
ArtifactTechnique Creator
Painting
Image
Integer
String
Conceptual Model (cm)String
Painter
String
String
String
xy property "xy"subPropertyOfsubClassOf
exemplified_by
exemplifies
created_by
creates
painted_by
paints
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TU/e eindhoven university of technology
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Art EncyclopediaArt Encyclopedia (ae)
ArtTechniqueLiteral
Literal
title
Artist
Literal
used
Tec
hniq
ue
biography
ArtPiece
Literal title
Literal date
Literal
xy property "xy"subPropertyOfsubClassOf
Art Catalogue (ac)
Exhibit
VisualArt
Music Piece
AudioArt
Painting
LiteralLiteral
MoviePhoto
Literalexhibited
Literalvisualized
creationDatetitle
Literal
Source Clusters
Sources are
• Autonomous
• (Virtually) grouped to clusters based on the content they provide
• RDF(S), RQL capable
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TU/e eindhoven university of technology
July 2003 11
Integration Model
IM decouples the CM and Sources • Articulations
– actual links between the CM and the source ontologies– concept/instance uniqueness – (a part of it) serves as a query on the source side
• Decorations– offer a way to rank sources within the same cluster– capture explicitly designer’s knowledge about sources– the order in which the sources are consulted is flexible– open possibilities for queries with constraints
e.g. “I’m interested in the answer within 1 s, otherwise forget it”
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TU/e eindhoven university of technology
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Integration Model Ontology
Integration ModelSpecialization
IntegrationModel Ontology
Reliability
ResponseTime
Decoration
Articulation To
FromLiteral
Comparator
PathExpressionNode
rdfs:Resource
Edge
rdf:Property
begins
ends
starts ToNode
starts FromNode
PrimaryNode
ProcInstruction
Transformer
Literal2String
Sn2UriTrans
xy property "xy"subPropertyOfsubClassOf
backtrack
follow
target
applies
obtainedFrom
srcAddress
Literal
App
lica
tion
inde
pend
ent
• Path expression– Primary node (including its
ID)– Sequence of nodes and edges
• Articulation– Target and Source path
expressions
• Decoration– Value based ordering criterion – e.g. ResponseTime, Reliability
• Processing instruction– Transformers (e.g.
Literal2String)
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TU/e eindhoven university of technology
July 2003 13
Integration Model Instance:Articulation Example
a2_1
pe_to3
pe_from3
cm:Painting
ac:Painting
cm:picture
ac:visualized
d2_1 0.9
URL2ImageTransfac:title
target
source
starts
starts
idByValue
obtainedFrom
idByValuetransformedBy
obtainedFrom
follow ends
follow
http://www…ac
appliessrcAddress
Decoration (Reliability)
Source Path Expression(query for the source)
Target Path Expression
cm:aname
endsLURL
Image
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TU/e eindhoven university of technology
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Source Management
Integration ModelSpecialization
IntegrationModel Ontology
Reliability
ResponseTime
Decoration
Articulation To
FromLiteral
Comparator
PathExpressionNode
rdfs:Resource
Edge
rdf:Property
begins
ends
starts ToNode
starts FromNode
PrimaryNode
ProcInstruction
Transformer
Literal2String
Sn2UriTrans
xy property "xy"subPropertyOfsubClassOf
backtrack
follow
target
applies
obtainedFrom
srcAddress
Literal
Back-end Front-end
Sources
User Query
Presentation
Integration Model
IM Specialization
Conceptual Model
IM Instance
Access Point
html/smil
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TU/e eindhoven university of technology
July 2003 15
Query answering
• Query mediation – For every variable in the query find articulations in the
IM instance pool – If there more articulations for one variable sort them
based on the chosen decoration(s) – Execute the “source” path expression queries at the the
sources – Perform the required processing instruction/data
transformations– Assemble the results
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TU/e eindhoven university of technology
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Application Model (AM)
• AM serves as a presentation blue-print• Describes hypermedia aspects of the presentation.• Captures the navigational view over the CM• Consists of (nested) slices and slice relationships
– Slices - meaningful presentation units• Associated to concepts from the CM• Contain properties and possibly other slices (nesting)
– Slice relationships:• Aggregation relationships: index, tour, indexed guided tour…• Reference relationships: link with an anchor specified.
• Encoded in RDF(S).
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TU/e eindhoven university of technology
July 2003 17
Application Model Example
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TU/e eindhoven university of technology
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Adaptation/User Model
• Captures two kinds of adaptation– Adaptability takes into account the situation in which the user will use
the presentation (e.g. the browsing platform). – Adaptivity means that the presentation changes itself according to the
“state of the user’s mind” while being browsed.
• Consists of – Device/User Profile captures “static” visual and platform preferences
encoded in CC/PP.– User Session represents the dynamic user’s state, e.g. did the user visit
(learn) this slice (concept). – Application and Update Rules describe the behavior of the presentation
(e.g. conditional slices in AM) and keep the User Session up-to-date (AHAM rules).
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TU/e eindhoven university of technology
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Adaptation Model Example
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TU/e eindhoven university of technology
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Adaptation Model Syntax
• Adaptability Condition
• Adaptivity Condition
<rdfs:Class rdf:ID=“Slice.painter.main”
slice:condition=“um:Technique < 10”>
<rdf:subClassOf rdf:resource=“#Slice”/>
</rdfs:Class>
<rdfs:Class rdf:ID=“Slice.painting.picture”
slice:condition=“prf:ImageCapable=Yes”>
<rdf:subClassOf rdf:resource=“#Slice”/>
</rdfs:Class>
PACIS'03
TU/e eindhoven university of technology
July 2003 21
Profile Example
• Device/User Profile (CC/PP encoding)Screen size: 100x80, preferred language: English
<ccpp:component>
<up:UserPreferences>
<up:Language>English</up:Language>
…
</up:UserPreferences>
</ccpp:component>
</rdf:Description>
<rdf:Description rdf:about=“Profile”>
<ccpp:component>
<prf:HardwarePlatform>
<prf:ImageCapable>No</prf:ImageCapable>
<prf:ScreenSize>100x80</prf:ScreenSize>
…
</prf:HardwarePlatform>
</ccpp:component>
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TU/e eindhoven university of technology
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XSL
Rendering• XSLT code generation• Different code generators:
– HTML for PC Web browsers
– SMIL code for multimedia presentations
– WML code for WAP phone browsers
XSL
<xsl:template match=“slice-instance”>
<TABLE>
<xsl:apply-templates select=“*”/>
</TABLE>
</xsl:template>
<xsl:template match=“slice-instance”>
<CARD id=“{@id}”>
<xsl:apply-templates select=“*”/>
</CARD>
</xsl:template>
HTMLWML
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TU/e eindhoven university of technology
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Resulting Hypermedia Presentations
HTML
WML
SMIL
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TU/e eindhoven university of technology
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EROS: exploring the CM
• Explorer for RDFS-based OntologieS
• multiple views over the same model
• support for RQL queries construction
,::
,::: 22212111
LRCVARpDCVAR
LRCVARpLRCVARpDCVAR
nnnnn
PACIS'03
TU/e eindhoven university of technology
July 2003 25
Summary
CM inRDF, RDFS
RQL
IM ArticulationsIM Decorations
AM inRDF, RDFS
UM, U/P Profile (CC/PP)
Hera:• Semantics– Express concepts and their hierarchies
– Relationships among the concepts
– Query language that can exploit the above
• Access to several sources– Flexible source management
– Flexible query mediation
• User/platform adaptation
– (adaptability and adaptivity)
• Automated presentation design– Based on the user query,
– Device profiles and the browsing history
PACIS'03
TU/e eindhoven university of technology
July 2003 26
Present & Future Work
• Applying our approach in different domains– Virtual museum
– Photo Portal
– Medical science (drug/disease ontologies)
• Optimization issues• Authoring tools for the underlying models