Hera: Development of Semantic Web Information Systems
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Transcript of Hera: Development of Semantic Web Information Systems
TU/e technische universiteit eindhoven
Hera: Development of Semantic Web Information Systems
Geert-Jan Houben
Peter Barna
Flavius Frasincar
Richard Vdovjak
TU/e technische universiteit eindhoven
Overview
• WIS design
• Hera methodology, RDF(S)
• Conceptual model and integration
• Application model and adaptation
• User interaction
TU/e technische universiteit eindhoven
Motivation
• From Web pages to Web information system (WIS)
• Technologies from Semantic Web: RDF(S)
• Hera uses RDF(S) for effective support of WIS design
TU/e technische universiteit eindhoven
WIS Design
• Generation of hypermedia presentations: navigation structure– Presentation objects, e.g. pages
– Navigation connections, e.g. hyperlinks
• Integration from different sources: transparent repository– Management of semi-structured data
• Personalization: user adaptation
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Adaptation
• Presentations must be adaptable to different users/user platforms
• Devices (PC, PDA, WAP Phone, WebTV etc.)• Device capabilities (display size, memory size,
network speed, etc.)• User preferences (desired layout, navigation
patterns, etc.)• User browsing history
TU/e technische universiteit eindhoven
HERA Architecture
Relational Database
Object-Oriented Database
XML Database
ODB-XML Wrapper
RDB-XML Wrapper
Mediator/ Integrator
Logical Presentation
Logical-WML Presentation
HTML Presentation
SMIL Presentation
WML Presentation
Logical-SMIL Presentation
Logical-HTML Presentation
Information Retrieval
Hypermedia Presentation
…
…Query
Use
r/P
latf
orm
A
dapt
atio
n
TU/e technische universiteit eindhoven
Hera: WIS Design Methodology
• RMM, OOHDM, WebML, etc.• Sequence of steps in designing a web application• Model-driven approach:
– data/navigation/presentation
• Data transformations:– towards HTML, WML, SMIL, etc.
• Use of RDF(S) to specify different models and XSLT to transform (meta)data– subclass/subproperty – extensibility, e.g. CC/PP vocabulary
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
Conceptual Model (CM)
• 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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Conceptual Model Example
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Source Clusters Equipment Catalogue Photo Rental
Photo Stock Agency
Sources are• Autonomous • (Virtually) grouped to clusters
based on the content they provide• RDF(S), RQL capable
TU/e technische universiteit eindhoven
Integration ModelIM decouples the CM and Sources • Articulations
– actual links between the CM and the source ontologies– (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– open possibilities for queries with constraints
e.g. “I’m interested in the answer within 1s, otherwise forget it”
TU/e technische universiteit eindhoven
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
• Articulation
• Decoration
• Processing instruction
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Application Model (AM)
• Captures navigational view over CM, describing hypermedia aspects
• Slices are meaningful presentation units:– Associated to concepts from CM– Containing properties/attributes and possibly other slices
• Slices are linked together with slice relationships:– Aggregation relationships: index, tour, indexed guided tour
etc.– Reference relationships: link with an anchor specified
• Encoded in RDF(S)
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Application Model Example
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Adaptation
• WIS are accessed through multitude of devices and by different users– Device capabilities
– User preferences
– Browsing history
• Adaptation based on conditioning the appearance of slices in AM
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Adaptation/User Model
• Captures two kinds of adaptation• Adaptability takes into account the context 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 Model 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 model up-to-date (AHAM rules)
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
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>
TU/e technische universiteit eindhoven
TU/e technische universiteit eindhoven
Adaptation Model Syntax
Adaptability Condition
Adaptivity Condition<rdfs:Class rdf:ID=“Slice.painter.main”
slice:condition=“um:Biography = false”>
<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>
<rdfs:Class rdf:ID=“Slice.painting.main”
slice:condition=“um:Painter > 10”>
<rdf:subClassOf rdf:resource=“#Slice”/>
</rdfs:Class>
TU/e technische universiteit eindhoven
User Interaction
• E-commerce applications often require WIS with broader functionality than just navigation through static web sites (known patterns: shopping carts, on-line payments, searches, etc.)
• The functionality includes also richer means of interaction with users via interaction elements: buttons, text entry forms, checkboxes, etc.
• Navigation objects (slices) with data content may depend on the interaction and/or system business logic, so it cannot be static
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User Interaction Specification
• Extension of AM specification:– Structural: interaction elements as “active” attributes
capturing user actions (buttons, text fields, etc.)– Behavioural: operations assigned to interaction
elements (dynamic navigation, data manipulation, adaptation, call of external Web Services, etc.)
• Consequence on WIS architecture: need for an engine providing the operations (as AHA! for adaptivity)
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Shopping Cart: example of CM data manipulations
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Conclusion & Future Work
• Explicit semantics in models, expressing concepts, their hierarchies and relationships
• Adaptation in all design steps including the CM and IM, and full support of adaptivity
• Experiment with higher ontology languages (e.g. OWL) as the basis for the different models
• Further development of authoring tools helping the designer to build models in all design steps– Query and transformation language, e.g. RAL
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