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L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB eLearning and Semantic Web Rudi...
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Transcript of L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB eLearning and Semantic Web Rudi...
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
eLearning and Semantic Web
Rudi StuderChristoph Schmitz, Steffen Staab, Gerd Stumme,
Julien Tane
Learning Lab Lower Saxonyhttp://www.learninglab.de
Institute AIFB, University of Karlsruhehttp://www.aifb.uni-karlsruhe.de/WBS
AIFB
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Overview
Motivation
Semantic Web: Ontologies and Metadata
Ontology-based eLearning
Conclusion
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Motivation
eLearning aims at replacing• time
• place
• content predetermined learning
with a • task-relevant
• personalized
• just-in-time
• active process of learning
How do we achieve these objectives?
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Metadata eLearning Standards
Approach:• Provide descriptions of learning resources• Enable search and query• Enable configuration of learning components
Goal:
To promote and facilitate the discovery,
retrieval, and composition of relevant
eLearning materials
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Current Metadata Standards for eLearning IEEE LOM (Learning Object Meta-data)
ARIADNE – Alliance of Remote Instructional, Authoring and Distribution Networks for Europe
IMS – Instructional Management System Global Learning Consortium
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Characteristics of Current Approaches
<Classification> <Taxonpath> <Taxon> <Entry> Engineering </entry> <Taxon> <Entry> Electr. Engineering </entry> <Taxon> <Entry> <langstring xml:lang="en"> Integrated Digital Circuit </langstring> </Entry> </Taxon> </Taxon> </Taxon> </Taxonpath> </Classification>
<SemanticsOfTheResource>
<Discipline> Engineering </Discipline> <Subdiscipline> Electr.
Engineering <Subdiscipline> <MainConcept> Integrated Digital
Circuit </MainConcept> <MainConcept> Chip </MainConcept> <OtherConcepts> CMOS </OtherConcepts></
SemanticsOfTheResource>
Challenges:– Name Conflicts– Structure Conflicts– Limited Semantics
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Limitations of current Web-based solutions
search and query is restricted to keyword-based methods
contents of course components is captured only partially
lack of flexible customization to user needs
lack of flexible configuration of course components
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Overview
Motivation
Semantic Web: Ontologies and Metadata
Ontology-based eLearning
Conclusion
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Semantic Web
“The Semantic Web: a new form of Web content that is meaningful to computers will unleash a revolution of new possibilities“
(Tim Berners-Lee et al., Scientific American, 2001)
Make content accessible and interpretable by machines
Provide metadata that come with precisely defined semantics
Provide shared vocabulary
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Meaning Triangle“People [and machines] can’t share knowledge if they don’t speak a common language” (Davenport)
Symbol Thingstands for
refers toevokes
Concept
jaguar
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Ontologies
“An ontology is an explicit specification of a conceptualization“
(Gruber 1993)
Ontologies offer
a conceptual foundation for communication between actors
a formal basis to define a vocabulary
a vocabulary that is shared among a group of actors
Ontologies are used at run time, they are part of the eLearning application
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Ontologies and RDF/RDFSchema
RDF/RDFSchema provide modelling primitives for lightweight ontologies
• classes and subClass hierarchies• properties and subProperty hierarchies• domain and range specifications for properties• instances
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Ontologies & RDF(S)rdfs:Resource
rdfs:Class
rdf:Property
RD
F/R
DF
S l
ay
er
an
d n
am
es
pa
ce
ap
pli
ca
tio
n s
pe
cif
ic
sc
he
ma
an
d n
am
es
pa
ce
appl:Document
appl:Protocol
appl:Title
ap
pli
ca
tio
n s
pe
cif
ica
ctu
al
da
ta
http://www.fzi.de/WIM/Protocol.html
„RFC2068: Hypertext transfer Protocol“
appl:Titleappl:content
subClassOf
instanceOf
appl:Topic
appl:Service
appl:content
HTTP Protocol
Subject
Predicate
Object
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Semantic Web & Ontologies
More heavyweight ontologies all to capture more semantics of a domain
• prevDocument and nextDocument are inverse to each other• subClassOf is transitive• axioms yield additional knowledge:
teaches (prof1, course2) and isAbout (course2, ontologies)
knowsAbout (prof1, ontologies)
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Overview
Motivation
Semantic Web: Ontologies and Metadata
Ontology-based eLearning
Conclusion
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Semantic Web & eLearning
The Semantic Web is a very suitable framework for realizing some aspects of eLearning systems
Development steps:• collaborative ontology development for eLearning
• ontology-based annotation of learning material
• integration of learning resources
• dynamic composition of course material
Access:• proactive delivery of the learning materials
• integrated browsing and query facilities
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Conventional Metadata for eLearning
<Classification> <Taxonpath> <Taxon> <Entry> Engineering </entry> <Taxon> <Entry> Electr. Engineering </entry> <Taxon> <Entry> <langstring xml:lang="en"> Integrated Digital Circuit </langstring> </Entry> </Taxon> </Taxon> </Taxon> </Taxonpath> </Classification>
<SemanticsOfTheResource>
<Discipline> Engineering </Discipline> <Subdiscipline> Electr.
Engineering <Subdiscipline> <MainConcept> Integrated Digital
Circuit </MainConcept> <MainConcept> Chip </MainConcept> <OtherConcepts> CMOS </OtherConcepts></
SemanticsOfTheResource>
Problems:• Lack of formal semantics • Different vocabularies for metadata
• Lack of semantic mapping
• Ontologies are suitable as a conceptual backbone• Define shared understanding• Provide semantic underpinning for metadata
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Ontology-based MetadataMetadata in eLearning are concerned with several orthogonal dimensions:
• What the learning material is about (content) • What is the learning situation (context)• How is the learning material connected to other learning materials (structure)
Learningresource
Content
Context
Structure
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Ontology-based MetadataBenefits in the process of providing and accessing information: Synonyms
“Agent” and “Actor” Different languages
“Lecture” (English) and “Vorlesung” (German) Morphological variations
“eLearning” and “e-Learning” Semantic relationships
“Computer Science” is a superTopicOf “Database Systems”
„Professor“ is related to „Course“ via the teaches relation
„CS101“ is an instanceOf „Course“
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Overview
Motivation
Semantic Web: Ontologies and Metadata
Ontology-based eLearning
Conclusion
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Conclusion
Ontologies can support eLearning in three ways:
for describing the semantic content of the learning materials,
for defining the learning context and
for describing the structure of the learning materials
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Conclusion
This three-dimensional, semantically structured space enables
• semantic querying PADLR module Edutella
Presentations byChristoph Schmitz and others
• semantic navigation PADLR module Courseware Watchdog
Presentation by Julien Tane• flexible combination and personalization
of learning resources
L3S Open Day 4. Dezember 2002 © 2002 Rudi Studer, Institut AIFB
Thank you!
Learning Lab Lower Saxony
http://www.learninglab.de
Institute AIFB, University of Karlsruhe
http://www.aifb.uni-karlsruhe.de/WBS
AIFB