José-Luis Pérez-de-la-Cruz

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Student assessment is a very important issue in educational settings. The goal of this work is to develop a web-based tool to assist teachers and instructors in the assessment process. Our system is called SIETTE, and its theoretical bases are Computer Adaptive Testing and Item Response Theory. With SIETTE, teachers worldwide can define their tests, and(More)
In this paper, we present a new approach to diagnosis in student modeling based on the use of Bayesian Networks and Computer Adaptive Tests. A new integrated Bayesian student model is defined and then combined with an Adaptive Testing algorithm. The structural model defined has the advantage that it measures students' abilities at different levels of(More)
The article describes and analyzes NAMOA<sup>*</sup>, an algorithm for multiobjective heuristic graph search problems. The algorithm is presented as an extension of A<sup>*</sup>, an admissible scalar shortest path algorithm. Under consistent heuristics A<sup>*</sup> is known to improve its efficiency with more informed heuristics, and to be optimal over(More)
In this paper we present an integrated theoretical approach for student modelling based on an Adaptive Bayesian Network. A mathematical formalization of the Adaptive Bayesian Network is provided, and new question selection criteria presented. Using this theoretical framework, a tool to assist in the diagnosis process has been implemented. This tool allows(More)
This paper presents an approach to student modeling in which knowledge is represented by means of probability distributions associated to a tree of concepts. A diagnosis procedure which uses adaptive testing is part of this approach. Adaptive tests provide well-founded and accurate diagnosis thanks to the underlying probabilistic theory, i.e., the Item(More)
In this paper we present an extension of a previously developed generic student model based on Bayesian Networks. A new layer has been added to the model to include prerequisite relationships. The need of this new layer is motivated from different points of view: in practice, this kind of relationships are very common in any educational setting, but also(More)
Testing is the most generic and perhaps most widely used mechanism for student assessment. Most tests are based on the classical test theory, which says that a student's score is the sum of the scores obtained in all questions plus some kind of error. The most relevant is that the student test result depends heavily on the individual's learning preferences(More)
Bayesian networks are graphical modeling tools that have been proven very powerful in a variety of application contexts. The purpose of this paper is to provide education practitioners with the background and examples needed to understand Bayesian networks and use them to design and implement student models. The student model is the key component of any(More)
In the last few years the use of coalition formation algorithms in multi-agent systems has been proposed as a possible way of modelling autonomous agent cooperation. Game theory provides different concepts for the stability of solutions in cooperative games, regarding the fairness of the resultant payment configuration. One of these is the core. In this(More)
P2P file sharing systems are distributed systems consisting of interconnected nodes able to self-organize in networks, with the purpose of sharing content. Recent empirical studies have shown that they suffer from freeloaders, that is, peers that consume many more resources or content than they contribute. In this paper we propose a coalition formation(More)