We have presented an architecture with a clear objective: to enable the universal reusability of learning objects. Besides providing an efficient solution to this problem, we also present an implementation that allows showing all the explained theoretical content. The system developed from the above mentioned architecture has been called LORS (Learning Object Reusability System) and represents a federated repository.
The Java platform has been chosen for the development of the system due to the fact that it is considered as the most currently used. Besides, it is perfectly bounded to the Web development. When SOA architecture is used, the presented system will be completely accessible from any other programming language, platform or system that uses any communication protocol. Also it enables to incorporate new services without affecting the already developed system.
MySQL has been chosen as a database manager for the implementation of this architecture. Also the system led by Glassfish Server, has been chosen as an application server.
In the main user interface of the application (Figure 13.5) they can be seen the two possible actions that will be carried out: federated search and catalogue repositories. It is possible to add new repositories within the repositories management regard for the searches to take effect on them. This is one of the new and most important characteristics this system has, as the interoperability among them is guaranteed when all repositories follow the same search interface. Figure 13.4 shows how it would be the process of adding new repositories.
The other option offered by the initial website is “search”. As it was stated above, the searches done in this system follow the SQI specification; so it is necessary to create a session anonymous or with credentials before starting to look up. There is no user management device in this system, but a SQI management device, so the database table will be directly modified when adding new users.
Once validated, the same process will be followed for the validation of all repositories registered in LORS; so if we choose to create an anonymous session, it will be created similarly with all repositories LORS has access. Once created the session, the system offers two types of search: simple and advanced.
The advanced search, also called accurate search, offers the possibility of configuring several SQI parameters as the maximum number of results, the size of the result set, or the initial result. As it is an accurate search, it is done based on educational fields. Figure 13.7 shows how it would be the search interface.
In the case of the simple search or inaccurate search, searches are done on the basis of how many times they appear and how relevant they are the terms given in the search statement in the learning objects metadata. As in the previous case, SQI parameters can be established: maximum number of results, size of the result set and the initial result.
Once the search has been done the system will offer an ordered list with all those learning objects fulfilling the specifications set by the user. Figure 8 shows the offered list. Then, the user can download it by clicking the link. One of the main differences of this system is that the repository associated to LORS has an extra service that does not belong to the SQI specification. This way, it is possible to directly download educational material, instead of link to the author’s page as other repositories like Ariadne do.
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