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


Overview

Motivation

Semantic Web: Ontologies and Metadata

Ontology-based eLearning

Conclusion


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?


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


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


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


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


Overview

Motivation



Conclusion


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


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


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


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


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


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)


Overview

Motivation



Conclusion


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


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


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


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“


Overview

Motivation



Conclusion


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


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


Thank you!

Learning Lab Lower Saxony

http://www.learninglab.de

Institute AIFB, University of Karlsruhe

http://www.aifb.uni-karlsruhe.de/WBS

AIFB

l3s open day 4. dezember 2002 © 2002 rudi studer, institut aifb elearning and semantic web rudi...

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heavyweight ontologies