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On Interoperability of Ontologies for Webbased Educational Systems

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Title: On Interoperability of Ontologies for Webbased Educational Systems


1
On Interoperability of Ontologies for Web-based
Educational Systems
  • Yannis Kalfoglou, Bo Hu, Dave Reynolds

This work is sponsored by CROSI (Capturing,
Representing and Operationalising Semantic
Integration) a joint research project between the
University of Southampton and HP Labs _at_Bristol
with the support of AKT consortium
2
overview
  • Interoperability and ontologies
  • WBESs needs KE support
  • Global vs. multiple ontologies
  • K-Sharing demand technology supply
  • Empowering user communities
  • Evaluation feedback
  • Working examples
  • Engineering effort benefits
  • WBESs interoperability issues
  • (Semantic) Web vision WBESs role

3
Interoperability facts
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • Heterogeneity due to independently developed
    systems
  • Homogeneous groups have been resolving it in
    familiar, closed environments, but
  • endemic characteristic of the (Semantic) Web
    distributed, decentralised systems
  • Furthermore communities introduce and use their
    own semantics
  • Need to achieve structural as well as semantic
    interoperability

4
Interoperability solutions
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • need to expose and share information and
    knowledge between disparate systems
  • Ontologies as the means for knowledge sharing and
    reuse
  • In WBESs advocated as a common vocabulary for
    domain knowledge representation
  • Legacy KE technology which created a niche
    ontology engineering

5
Global ontology - pros cons
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • In the 90s dominant approach for KE use of a
    well crafted, top-level, formal ontology
  • Effective once it is ready reduces sharing and
    reuse costs
  • Caveats designing the perfect ontology
    syndrome
  • Irreconcilable arguments among engineers at
    design time
  • Inappropriate interpretations and usage at
    deployment time
  • Hard to maintain not stable over time
    obsolete knowledge
  • 10-15 years later
  • (Semantic) Web made ontologies far easier to
    publish, reach and access than KEs ever thought
    it would be possible
  • ontology engineering tools appeal to large
    audiences, not only ontology engineers
  • available informal ontologies outnumber by far
    formal ones
  • Consequently, ontology supply outstrip demand.

6
Multiple ontologies - issues
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • Proliferation of ontologies meant
  • scalability authoring, deployment, need to be
    catered for.
  • Interoperability of ontologies themselves
  • interoperability is no longer based on a single,
    consensual ontology but uses multiple ontologies.
  • need to achieve interoperability at the
    underpinning ontology level before achieving
    interoperability of WBESs (using those
    ontologies)
  • Call for ontology to ontology interoperability
    ontology mapping
  • Ontology mapping is not a solved problem though
  • a lot of potential solutions available, but
  • not integrated at the design phase
  • not easy to replicate integrate with other
    components
  • not automated, and not easy to maintain.

7
Using learners
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • learners access and use learning material
  • In KE typically encode it as learning objects
    (preferably as an ontology)
  • KEs model, encode and offer those to end users
    for immediate consumption
  • But this, arguably, ignores input from learners
  • Feedback and evaluation from learners should be
    used when modelling learning objects.

8
Using learners cntd.
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • (Web) users actively involved in various tasks
  • FOAF network (typical foaf user not a KE)
  • Blogging (users maintain them)
  • RSS (decentralised authoring)
  • P2P and other Web-based interaction
  • (Semantic) Web environment and modus operandi
    encourages active user participation
  • WBESs interoperability should exploit this
  • Early theoretical investigations promote the role
    of communities in knowledge sharing (Kents work)

9
KM setting
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • AKT consortium five UK universities, 65
    personnel dispersed in five UK cities
  • Collaborative tasks, KM at work
  • practice what you preach!
  • Task help new workers familiarize themselves
    with AKT
  • Learning material wide variety of digital media
    A/V streams, Web-casting, story telling,
    newsletters, etc.
  • Learning material was semantically annotated and
    encoded in an ontology

10
Engineering effort
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • Resulting ontology one of the few, well-crafted,
    state-of-the-art Semantic Web ontologies
  • Supports award winning applications (2003 SW
    Challenge winner) and a variety of AKT testbeds
  • It has a knock-on effect on sharing and reuse
  • But it took us 3 years to build it and is
    expensive to maintain

11
Using small, domain ontologies
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • We worked with smaller, domain- and task-
    specific ontologies
  • myPlanet a Web-based, ontology-driven,
    personalised organisational newsletter
  • Easier to build and maintain
  • Directly appealing to end-users/learners, but
  • Long term benefits difficult to quantify (limited
    learning material available)

12
Engaging users
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • Ontology-based Communities of Practice (ONTOCOPI)

13
Engaging users cntd.
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • Ontology Network Analysis (ONA)

14
Ontology mapping
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues

Information Flow based Ontology Mapping
a method and a theory for Ontology mapping
Reference ontology
15
Multi- vs. single ontology
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • more than one ontology needed to support WBESs
  • (Semantic) Web made that easier
  • difficult to quantify and weigh the benefits of
    multiple vs. single ontology support for a WBES
  • If a typical WBES (single domain, std learning
    obj) then a single ontology is good enough
  • If a complex WBES (variety of learning obj,
    multi-domain), then multiple ontologies are
    needed
  • lack of requirements analysis
  • (not in general but specifically for ontology
    support)

16
Semantic Web enabled
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • Semantic Web is both a challenge
  • which ontology to use and how to choose the right
    one?
  • authority and version control, inconsistency,
    incompleteness, trust and provenance
  • and an opportunity for WBESs
  • abundance of ontologies available for use
  • Semantic Web built-in support for
    interoperability (OWL constructs)

17
Semantic interoperability
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • Need to focus on semantics, structure alone
    cannot solve the interoperability problem
  • Semantic interoperability needed when dealing
    with ontologies (rich in semantics), even more
    when multiple ontologies are used in a WBES
  • WBES can inform semantic interoperability
    requirements thanks to their relatively uniform
    domain representation (learning material)

18
Community driven
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • WBESs provide access to large audiences/user base
  • These could provide feedback and evaluate WBESs
  • The quest is to find ways with which these users
    will inform and be involved in the
    interoperability process.
  • then we are realising the goal of having
    operational semantics exposed by their users.

19
Versatile content
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues
  • Traditional views of WBESs content need to be
    updated.
  • Many-forms, multiple-sourced, distributed digital
    content is easily accessible and available,
    nowadays
  • Thanks to the (Semantic) Web, it could also be
    semantically annotated.
  • WBESs should reflect this versatility and be able
    to accommodate many different kinds of content.
  • Typically, accommodate university-like online
    course material
  • Standardisation efforts on framework to assist
    integrating this content are already underway (EU
    PROLEARN project)

20
Questions?
  • Interoperability ontologies
  • Global vs. multiple ontologies
  • Empowering user communities
  • Working examples
  • WBESs interoperability issues

21
Using an ontology to achieve interoperabilityOnto
logies principles, methods and applications1996
- KER 11(2)93-136 Uschold Gruninger
22
Theoretical investigations on the role of
communities in K-SharingInformation Flow
Framework R.Kent, 2003
23
Information Flow Based Ontology Mapping
(IF-Map)IF-Map an ontology mapping method based
on information flow theoryY.Kalfoglou
M.Schorlemmer, JDS (1)198-127, 2003
24
Information Flow Based Ontology Mapping
(IF-Map)IF-Map an ontology mapping method based
on information flow theoryY.Kalfoglou
M.Schorlemmer, JDS (1)198-127, 2003
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