Academic journal article Journal of New Approaches in Educational Research

Practical Experiences for the Development of Educational Systems in the Semantic Web

Academic journal article Journal of New Approaches in Educational Research

Practical Experiences for the Development of Educational Systems in the Semantic Web

Article excerpt

1 INTRODUCTION: ONTOLOGIES AND THE SEMANTIC WEB IN ELEARNING

The Semantic Web aims to add semantic information to web contents in order to create an environment where software agents can perform tasks efficiently (Berners & Hendler, 2001). The Semantic Web proposes the idea that web contents are defined and linked not only for visualization but also to be used by applications. That is why the Semantic Web represents a promising technology to implement e-learning systems. Furthermore, Stojanovic, Staab, and Studer (2001) showed that the Semantic Web meets the basic e-learning requirements, namely: speed, just-in-time and pertinent learning. The appropriateness of Semantic Web technologies for developing eLearning systems is also supported by the research work undertaken in the last years from different perspectives (see Fensel, Staab, Studer, Van, & Davies, 2003; Devedzic, 2006; Bittencourt, Costa, & Silva, 2009; amongst others).

The Semantic Web has as its aim to go beyond the limits of the current web by introducing explicit descriptions of meaning, the internal structure and the overall structure of the contents and services available on the WWW. Before the chaotic growth in resources and the absence of any clear organization in the web today, it advocates a classification, structuring and annotation of resources with explicitations that can be processed by semantic machine.

A number of technologies are needed for the success of the Semantic Web. The Semantic Web stack includes languages and standards ranging from how characters are represented to how security can be guaranteed. However, ontologies have become the cornerstone of the technology required if all the information is to be made understandable by machines. A large number of definitions for ontology can be found in the literature (see Gruber, 1993 or Van Heist, Schereiber, & Wielinga, 1997, for instance). Ontologies define common, shareable and reusable views of a domain, giving meaning to information structures that are exchanged by information systems (Brewster & O'Hara, 2007). Ontology can be seen as a semantic model that contains concepts, their properties, interconceptual relationships, and axioms related to the aforesaid elements. In practical settings, ontologies have become widely utilized because they are reusable and shareable (see Fernández-Breis & Martínez-Bejar, 2002 and Brewster & O'Hara, 2007, amongst others).

On the e-Learning side, some standards and recommendations state the need for Semantic Web-based approaches. On the one hand, the Learning Object Metadata (LOM) standard recommends the annotation and classification of learning objects, using metadata to facilitate their retrieval. On the other hand, The IMS LD specification, which describes the learning process that takes place in learning units, is currently described using the ontology (Amorín, Lama, Sánchez, Riera, & Vila, 1995).

However, the development of ontologies has never been easy and getting such a degree of shared semantics in the web is a task that will take a few years. That is why Linked Data have been proposed as a way to facilitate data exchange in the Web. Linked Data permit using the Web to connect related data. According to Wikipedia, it describes a recommended best practice for exposing, sharing, and connecting data, information, and knowledge on the Semantic Web using URIs and RDF.

2 METHODS: INFORMAL AND FORMAL REPRESENTATIONS OF DATA AND KNOWLEDGE

This section provides more information about the nature and properties of ontologies that can turn out to be useful within learning environments; that will allow us to introduce how knowledge is used by the two research projects analysed in later sections of this paper.

The formal notion of ontology means that ontology knowledge is formal; it has a specific structure with a particular, deterministic, and inflexible meaning. This is probably a required property of ontologies in certain domains and applications, but it limits their applicability too. …

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