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Project of the Darmstadt University of Technology within the competence
network „New Services, Standardization, Metadata“ (bmb+f)
Stephan KörnigAli MahdouiJulia Stoll
Rudi Schmiede
A Generic Framework for the Exchange and Usage of Semantically Enriched
Information
NKOS Workshop, Trondheim 2003
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Outline
• Motivation / Goals of the Project
• Web Services• Digital Library Services for
Scientists• Applications• Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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Motivation
• Known problems for integration– Distribution of information /
Heterogeneity– Development technology-driven /
short cycles of innovation
• “Web Services” (W3C) as a promising standard
• Framework for scientific use of information is missing
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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Standards
• Standardization as a part of the problem– Standardization is research– Standardization of own developments
gives return on investment– Standards: high/low level of details
• Missing specs for Digital Library-Services– Background „dl-konzepte“: concepts for
the improvement of scholarly information systems
– Domain specific solutions required
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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Requirements
• Scope: scholarly information within scientific net(work)s
• (Technical & organizational) support of distributed systems
• Light-weight technology• Support of dynamic changes• Support of a (domain
specific) view on resources
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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Goals
• Specification of DL-Services• Generic Framework
supporting the implementation of scientific– portals– peer2peer networks– workspaces
• Organizational issues
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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Web Services - Basics• Again: this is about the W3C standard• Remote procedure calls via HTTP• Supports interaction of distributed, loose
coupled and reusable software components
• Integration of legacy systems / middle-ware for heterogeneous networks
• Openness: Machine readable description available (WSDL) – accessible via public (UDDI-) Registries
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
Provision of Web Services
Service Provider Service Requestor
Discovery Agency(UDDI) Service-
Descriptions(WSDL)
publish
interact
find
Scenario: Web Services based Infrastructure for Digital Libraries
UDDI-Registry
Existing web services
NewsserviceScientificdatabase
OAI based document harvester
XML/SOAP XML/SOAP XML/SOAP
Network-node 1
XM
L/SO
AP
WSDL-descriptions
Network-node 2
XM
L/SO
AP
Network-node n
XM
L/SO
AP
NKOS Workshop, Trondheim 2003
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WSDL – Limitations of the Standard• Still undergoing changes• Tries to support different
paradigms– Object orientation– Functional programming– (Relational) database access
• Some transformations will need support by specialized wrappers
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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DL-Services for Scientists
• Services: logical view• Generalization of Access
and Formats• Type system / Ontologies
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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DL-Services (logical view)
Service (user‘s perspective)
Types of services
Types of material
Metamodel
Functionality modeland implementation
Service Provision(Web-Service)
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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Access and Formats
Standardizationof access
Types of servicesand material
Metamodelof the framework
Standardization offormats/protocols
Interfacespecifications
WSDL descriptions
with differentlevel of
generalization
Task
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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KOS related DL- Services• Services allowing access to
thesauri / ontologies or concepts (eg Query expansion)
• More use cases?
• Problem in the context of our framework: Modeling with RDFS/OWL does not integrate into XML
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
Framework (logical view)
XML-Repository
Metamodelof Services
Support Services
Service <<facade>>
WSDL-Service Support
Generator
Service-Localization
Dispatcher
Webserver(Cocoon2)
Java-classes (framework application)
Service creation and
assembly Transaction- management
Data processedby Services
Framework (instantiation)
NKOS Workshop, Trondheim 2003
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Development Activities• Utilizing upcoming standards
or specifications (e.g. JXTA)• Ability to support the different
types of use cases (portal, P2P, workspace)
• Focus on application supporting the maintenance of content within a scientific portal for science nets
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse
NKOS Workshop, Trondheim 2003
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Cooperation/Clearinghouse• Importance of people behind
standardization effort• Cooperation on a national
level (network of competence)
• Utilizing international accepted standards
• Open for cooperation
Motivation / Goals of the Project
Web Services
Digital Library Services for Scientists
Applications
Cooperation / Clearinghouse