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Constructing Knowledge Bases for E-Learning Using Protégé 2000 and Web Services Presented by: Fuhua Oscar Lin Authors: Mike Hogeboom, Fuhua Oscar Lin, Larbi Esmahi Athabasca University, Canada Chunsheng Yang National Research Council, Canada AINA 2005, Tamkang University, Taipei, March 29 -30, 2005.
Edmonton, Athabasca Alberta Canada
E-Learning n Features Not driven by the instructor n Learners can access material in an order that is not predefined n Learners can compose individual courses by selecting educational material n
Agent-based Adaptive E-Learning n Distributed learning material (knowledge) must be equipped with additional information to support effective indexing and retrieval n Machine-understandable (XML-like approach): Metadata n Machine-accessible: Web services n Machine-sharable: Ontology
Web Services n n n A Web Service is a software system designed to support interoperable machine-to-machine interaction over a network. It has an interface described in a machine-processable format (WSDL) Other systems interact with the Web Service in a manner prescribed by its description using SOAPmessage, typically conveyed using HTTP with an XML serialization in conjunction with other Web-related standards.
Web Services n The Power of Web Services, in addition to their great interoperability and extensibility thanks to the use of XML, is that they can be combined in order to achieve complex operations.
Why Ontologies for E-Learning? Indexing problem: Different authors use different terminologies, in which case the combination of learning materials become difficult. n Retrieval problem: instructors and learners have very different backgrounds and levels of knowledge. n
Ontologies in e-Learning n Domain Ontology: describes the basic concepts of the domain in which learning takes place (e. g. history or computer science). It includes also the relations between these concepts, and some basic properties.
Pedagogy Ontology & Structure Ontology n Pedagogy ontology: representing pedagogical issues. n n For example, material can be classified as lecture, tutorial, example, walk-through, exercise, solution, and so on. Structure ontology: is used to define the logical structure of the learning materials. e. g. previous, next, has. Part.
Some Related Work on Ontology T. Gruber’s research on Portable Ontology Specifications deals with defining a common vocabulary in which shared knowledge is represented. n P. Saini has performed some research on Deriving Ontology-based Metadata for e. Learning from the ACM Computing Curricula. n
Ontology Design n (Noy, 2000) pointed out three fundamental rules in ontology design: n n n There is no one correct way to model a domain— there always viable alternatives. The best solution almost always depends on the application that you have in mind and the extensions that you anticipate. Ontology development is necessarily an iterative process. Concepts in the ontology should be close to objects (physical or logical) and relationships in your domain of interest. These are most likely to be nouns (objects) or verbs (relationships) in sentences that describe your domain.
Protégé 2000 An extensible infrastructure and allows the easy construction of domain ontology, customized data entry forms. n An API that can easily be extended by Web Services. n
Implementation Separates a publication into multiple pieces n Facilitates using the Protégé search API to its maximum potential n Makes searches more powerful and precise n Makes content more manageable once retrieved from the knowledge base. n
Class Diagram for e-Learning Protégé 2000 Knowledge Base abstract has . . ** has
How the Protégé 2000 classes relate to each other within the Protégé 2000
Actions Performed by E-Learning Clients n n n n n Load a previously saved session Create a new session Save a session View contents of a session Add content to the session Publish a session to HTML Search the e-Learning Web Services for content Search the e-Learning Web Services for authors Traverse forwards and backwards through individual pieces of content contained within a publication once a piece of content is found View all the topics/subject areas stored in the e-Learning knowledge base by querying the e-Learning Web Services
Five Web Services Used Get. Publication n Get. Topics n Search. Content n Get. Content n Search. Publications n
Leveraging XSL Technology n How leveraging XSL (Extensible Stylesheet Language) technology can be beneficial in publishing the retrieved content because it is easy to change the look and appearance of published content by changing the XSL style sheets. An example of published content.
Conclusions n n n Protégé 2000 is flexible and open enough to extend the Protégé API with Web Services Protégé 2000 supported the functions required for this project to search a knowledge base. RPC-style Web Services were chosen for this project because this type of service should be used within an enterprise, when there is reliable and high bandwidth, for short running business process, and when there is a trusted environment.
Conclusions This project also demonstrates the ease of use of the Java Web Services Developer Pack (JWSDP) combined with the Protégé 2000 Java API and how they can be extended to facilitate e. Learning and dynamic course creation. n The use of a standard such as Web Services in the form of SOAP RPC calls allows remote clients written in different languages to connect to the e-Learning Web Services n
Future Work Incorporating Automated Learning Support Agents into LMSs. n The Protégé knowledge base could be upgraded to a relational database to improve search times which decrease as the knowledge base becomes larger. n Logging statistics n
Educational Semantic Web (Vladan Devedzic, 2004)
Intelligent e-Learning Technologies Research Lab, Athabasca University, Canada http: //io. acad. athabascau. ca/~oscar/ Thanks!