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