The conceptual architecture of the envisaged Framework will consist of two main elements – Design-time Environment and Run-time Environment.
The Design-time Environment will propose:
Information structures for storing and retrieving semantic and non-semantic data:
- Semantic Web Service Repository enables efficient storage and retrieval of all elements of the Semantic Web (WSMO objects): goals, ontologies and Semantic Web Services.
- Learning Metadata Repository – will contain annotated metadata about Learning Objects, used for grounding of Semantic Web services.
- Information Indexer and Retriever - will contain a special representation of both Semantic (WSMO) objects and Learning objects stored in the corresponding information structures that will allow effective similarity-based retrieval of such objects based on their content.
Tools for creation and maintenance of resources, metadata and supporting ontologies:
- Semantic Web Service Creator aims at designing WSMO-based Semantic Web Services by reusing already existing semantic and non-semantic descriptions stored in the Semantic and Learning Metadata Repositories.
- Ontology Creator aims at creating ontologies in a user-friendly manner.
- Semantic Goal Creator will provide means for creation of WSMO-based reusable goals used for designing of SWS-based eLearning applications and end-user goals.
- Learning Content Description Tool aims at creating metadata annotation of multimedia and learning objects according to certain eLearning standards and some formal ontologies.
Methods used for creating and maintaining Semantic and Learning objects:
- Combination of eLearning-specific and logic-based methods for object discovery
- eLearning-specific decision-support methods for dynamic service composition
- Several methods for calculating similarity and object retrieval – structural, linguistic, statistical, fuzzy, etc.
The Framework Run-time Environment will be responsible for discovery, dynamic composition, execution and monitoring of SWS. The Run-time Environment will consist of the SWS Discoverer, SWS Composer and SWS Executor components.
The proposed Conceptual Architecture is an adaptation of the INFRAWEBS Semantic SOA-based architecture towards eLearning applications and presents a novel approach for creating and maintaining Semantic Web services and SWS applications. It is based on tight integration of similarity-based and logic-based reasoning. Similarity-based reasoning is used for fast finding of approximate solutions, which are further concretized by the logic-based reasoning.
The Project Framework will implement a layered approach for creation eLearning applications.
It is assumed that operation on different layers may be accomplished by different types of users of the Framework (Learning content and data Providers, Semantic SWS Providers and SWS Learning application Providers):
- First layer is devoted to creation of learning objects:
- At the beginning multimedia objects (eventually with some basic content annotations) will be retrieved from a Digital Object Repository (Digital Library) implemented as a Web service.
- The Learning Content Description Tool will then create Learning Objects by supplying missing administrative and technical meta-data, adding semantic descriptions of multimedia content according WSMO-based domain ontologies as well as some metadata for possible learning usages of the already annotated multimedia objects according IEEE LOM standard.
- The object publishing process is passed through the process of indexing object description done by the Information Indexer and Retriever component of the Framework implemented as Web service.
- The process of creating Learning Objects will be facilitated by ability to reuse the existing metadata descriptions of similar objects stored in the Learning Object Repository. The search of such similar objects is realized by the Information Indexer and Retriever based on object indexes created during the process of publishing the objects.
- The second layer is devoted to converting the Learning Objects into Semantic Web Services:
- Some metadata description of Learning Objects stored in the LO Repository will be further used for creating SWS described according to WSMO Methodological Framework. Such services are designed by the SWS Creator tools actively exploring already prepared service ontologies (by means of Ontology Creator tool).
- As in the case of creating the Learning Objects, the process of creating SWS description will be significantly facilitated by cooperation with the Information Indexer and Retriever component of the Framework, which allows affective reuse of already created Semantic Services stored in the SWS Repository.
- The newly created Semantic Web Services are published in the SWS Repository, which makes them available for discovery and composition by means of Run-time Environment of the Framework.
- Third layer is devoted for dynamic composition and delivery of Semantic Services:
- At design-time some learning goals (represented as WSMO goals) describing possible goals of the end-user of a SWS Learning application are created by Semantic Goal Creator tool, which intensively uses some formally represented learning strategy ontologies. These goals will be the basic blocks for formulating end-user queries to a SWS Learning application in run-time.
- In Run-time each end-user goal will be dynamically decomposed on sub-goals, for which the corresponding sets of matching Semantic Services will be discovered. The resulted dynamically composed complex process may be stored again in the SWS Repository as a new complex Semantic Service or be executed by the Framework Run-time Environment.