H. Alballaa, A. Chikh

King Saud University (SAUDI ARABIA)
Advances in technology have helped creating an overabundance of learning opportunities. Education professionals distinguish between three types of learning: Formal learning, informal and non-formal learning.

Recent advances in technology and Web 2.0 has helped blur the distinction between formal and informal learning opportunities in higher education. Blending of both formal and informal learning are essential; an effective learning space combines formal and informal learning (Cross, 2007; Trentin and Repetto, 2013).

Often information about different types of learning opportunities is announced over the Internet, cluttered and distributed among many diverse and heterogeneous systems. The lack in interoperability of learning resources and learning technologies is presumed to adversely affect content developers, technology providers, educators, and learners.(Najjar et al., 2011); This emphasizes the need for creating an infrastructure for advertising and accessing the information in a way that makes it more useful, organized, and accessible for students, researchers, and the general public at a universal scale (Lezcano et al., 2013).

Metadata research is a promising area that emerged crosscutting many domains, focusing on the provision of distributed annotations and description which serves as a foundation for interoperability and advanced services in many application areas, including education, government, research, and social being (Edwards et al., 2011; Greenberg and Garoufallou, 2013; Sicilia, 2009).

Another set of principles and technologies, which holds promise for connecting distributed and heterogeneous systems on a massive scale, is Linked Data. It builds on Semantic Web technologies; where data is encoded in the form of subject, predicate, and object also known as RDF triple. It presents an approach for information interoperability based on creation of a global information space (Heath and Bizer, 2011). Data that are both open and linked are referred to as Linked Open Data (LOD) (Zuiderwijk et al., 2012).

Metadata is viewed as building blocks for LOD (Busch et al., 2012). Metadata can provide a context for data and is viewed as the backbone for improving storing, accessing, discovering, visualizing, creating order within datasets, stimulating analysis, reusing, reproducing and finding inconsistencies in LOD (Zuiderwijk et al., 2012).

Metadata for Learning Opportunities -Advertising (MLO-AD), is a European standardized model addressing metadata for advertising learning opportunities. MLO-AD is based on XCRI (eXchange of Course-Related Information) standard for Course Description (Arcella et al., 2009)
MLO-AD was developed by a group of 21 experts from 12 countries within Europe, and was designed to facilitate semantic technologies and web architectures to support several mechanisms for exchange and aggregation of information by third party service suppliers. (Anido-Rifón et al., 2013; CEN, 2009).

This paper has two aims. First, it aims at introducing a survey of the most significant work in the field. Second, it proposes a general model illustrating the key concepts surrounding the learning opportunity concept and highlighting their relationships.