Abstract. Recommender Systems aim to provide users with search results close to their needs, making predictions of their preferences. In virtual learning environments, Educational Recommender Systems deliver learning objects according to the student's characteristics, preferences and learning needs. A learning object is an educational content unit, which once found and retrieved may assist students in their learning process. In previous work, authors have designed and evaluated several recommendation techniques for delivering the most appropriate learning object for each specific student. Also, they have combined these techniques by using hybridization methods, improving the performance of isolated techniques. However, traditional hybidization methods fail when the learning objects delivered by each recommendation technique are very different from those selected by the other techniques (there is no agreement about the best learning object to recommend). In this paper, we present a hybrid recommendation method based on argumentation theory that combines content-based, collaborative and knowledge-based recommendation techniques and provides the students with those objects for which the system is able to generate more arguments to justify their suitability. This method has been tested by using a database with real data about students and learning objects, getting promising results.
MotivationAccording to the IEEE, a learning object (LO) can be defined as a digital entity involving educational design characteristics. Each LO can be used, reused or referenced during computer-supported learning processes, aiming at generating knowledge and competences based on student's needs [1]. LOs have functional requirements such as accessibility, reuse, and interoperability. The concept of LO requires understanding of how people learn, since this issue directly affects the LO design in each of its three dimensions: pedagogical, didactic, and technological [2]. In addition, LOs have metadata that describe and identify the educational resources involved and facilitate their searching and retrieval. Learning ObjectsCorresponding author.Repositories (LORs), composed of thousands of LOs, can be defined as specialized digital libraries storing several types of heterogeneous resources. LORs are currently being used in various e-learning environments and belong mainly to educational institutions [2,3]. Also, federations of LORs provide educational applications to search, retrieve and access specific LO contents available in any LOR [4]. Recommender Systems aim to provide users with search results close to their needs, making predictions of their preferences [5]. In virtual learning environments, Educational Recommender Systems (ERS) deliver LOs according to the student's characteristics, preferences and learning needs. In order to improve recommendations, ERS must perform feedback processes and implement mechanisms that enable them to obtain a large amount of information about users and how they use the LOs. ERS can be classified into s...