Propuesta de una arquitectura para búsqueda federada y agregación semántica de objetos de aprendizaje en repositorios distribuídos

Abstract

The objective of this Thesis is a software architecture suggestion for the construction of a system which allows federated search and semantic aggregation of learning objects in an universal way so it will be possible to integrate them in learning or e‐Learning system. At the present time the learning systems are reaching a great proliferation as it is demonstrated by the numbers that can be found in the published works about the subject. Nevertheless these systems develop at the same time that the standards to which they try to adapt. The learning systems use learning objects (LO) as content base of their courses. These objects are located at repositories, which are digital stores of educative resources. These repositories implement a collection of resources (objects and/or units of learning) that is accessible through a communication network. The aim of a repository is to facilitate the reusability of those educative resources, making easier the access to them. A learning object can be reused if it is made up in such a way that it is supported at least to some labelled standard associated to the contents that support, as well as that determines its construction and packaging. In the current state of development, there are systems already implemented that make possible a more or less efficient search of educational content distributed in repositories. These systems, interoperable between them in most cases, do not present efficient searching mechanisms; since they realize them being based on a user introduced terms, instead of doing it on the meanings. It has produced a great advance as for what the distribution of contents refers, but not as for the data processing, very important factor in this kind of systems. In summary, we are in the presence of a situation in which the platforms and e‐learning systems, though they present applications that interconnect them allowing the distribution of educational content, they do not rely on efficient searching mechanisms and information analysis. In addition, it can be incorporated new tools that facilitate moreover the reusability of the educational content that these distributed repositories shelter. The proposed solution is the definition of a functional and architectonic frame for the adaptation of a system based on SOA and implemented through Web services (what provides a flexible integration mechanism of different applications and resources discovery in Internet) that assures the interoperability of different learning objects repositories and which assure their reusability. This architecture, being based on the main standards and specifications, it will take as a differ characteristic that will allow not only the search and isolated educational material reusability, but it will allow in addition the search of complete courses, obtaining all the modules or individual parts that compose the above mentioned course, using for it semantic technologies that guarantee the efficiency of the same ones. In addition, a series of modifications are defined to some of the specifications that exist nowadays, so that there are relieved some of the faults which the author has found at the moment of his follow‐up and implementation. In this Thesis, in the first place it is analyzed the present state of e‐learning systems (also of learning based on the Web or Internet), their proposals, their advances and mainly their restrictions. Within this document it will be made a special emphasis in the repositories study that sustain them and the standards that point out how to construct them. From these studies we will indicate the present restrictions and we will define our proposals to solve them. It is proposed layers architecture of the system that includes a series of requirements that will have to be noticed like basic norms necessary to consider in every system based on this architecture. Also it is defined the needed components to assure the required functionality, as well as the information flow and the relations among them. This doctoral document ends with the presentation of conclusions and future works related to the treated subjects. It has been also included a last point with the documentary sources (including Internet links) in which we have been inspired, without any intention of thoroughly in a referential frame subdue to intense and continuous changes.