## 4 SERS Requirements
### Discussion  
Although current LMS do not properly cover personalization and accessibility issues, and are still struggling to support the reusability requirements coming from the need of a pervasive usage of standards and specifications, efforts in the LMS field are being done towards building the third generation of LMS following a fully service-oriented approach. Moreover, as compiled in Table 1, a wide set of standards and specifications exist that can be used to describe characteristics of the recommendations, although in some cases there is overlapping of information and in others lack of required descriptions. These issues are being addressed in the research arena [17; 20]. Thus, there is a need to provide the required semantic support for information exchange among components. In this context, solutions that allow offering personalized inclusive support in service-oriented and standards-based LMS are of value, especially if they support modularization of the required functionalities.  
Standards and specifications can be used to represent long-term information needs for the recommendation process, and thus, provide the foundations for the semantic modeling of the knowledge required for the recommendation process. In this way, the following nine issues mentioned in [30] are addressed in the SERS approach to a greater or lesser extent: (i) inter-operability of system resources and homogeneity of the information representation; (ii) dynamic contextualization of user preferences; (iii) performance in social networks and collaborative filtering; (iv) communication processes between agents and between agents and users; (v) limitation of the cold start problem through inferences; (vi) semantically extended descriptions of user contextual factors; (vii) representation and description of different system elements; (viii) description of system logic by admitting the inclusion of a set of rules; (ix) descriptions enriched by web services to facilitate their discovery by software agents.  
Bearing the above issues in mind, the SERS approach defines three requirements, namely a recommendation model, an open service-oriented architecture and a graphical user interface. These requirements are strongly interrelated due to the semantic descriptions shared among them, which rely on existing standards and specifications. However, there is also room to new standards and specifications that provide better descriptions of the educational functionalities provided within LMS, which support the interrelations when describing restrictions and applicability conditions, as well as the descriptions of the semantic information elements, that is, category, stage, origin and relevance. The recommendation model characterizes the recommendations in a way that specifies when they have to be delivered and how they are presented to the user, and thus, facilitates the interpretation of the semantics of the data exchanged. The service-oriented architecture supports the information exchange among the different components involved in the recommendation process. The graphical user interface is the communication channel with the learner and presents the information used by the components in a human readable way.  
In this way, the learners' needs during the learning process are supported by providing educational oriented recommendations that take into account their interaction needs in the course to provide and effective, efficient and satisfactory learning experience. This is meant to attend the needs of every learner, including their disabilities, access preferences and context by considering web contentaccessibility guidelines (WCAG), along with learners' accessibility preferences in ISO PNP and IMS AccLIP and the characteristics of the devices used (CC/PP).