Abstract. 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 their use allows for improving efficiency of both adaptation mechanisms and the inference process. The new prerequisite layer has been evaluated using two different experiments: the first experiment uses a small toy example to show how the BN can emulate human reasoning in this context, while the second experiment with simulated students suggests that prerequisite relationships can improve the efficiency of the diagnosis process by allowing increased accuracy or reductions in the test length. 1.

To improve today’s multimedia retrieval tools and thus the overall satisfaction of a user, it is necessary to develop methods that are able to support the user in the retrieval process, e.g. by providing not only additional information about the search results as well as the data collection itself, but also by adapting the retrieval tool to the underlying data as well as to the user’s needs and interests. In this chapter we give a brief overview of the state-of-the-art and current trends in research.

Several researchers have suggested that Bayesian networks be used in web search and user profiling. One advantage of this approach is that Bayesian networks are more general than the probabilistic models previously used in information retrieval. In practice, experimental results demonstrate the e#ectiveness the modern Bayesian network approach. On the other hand, since Bayesian networks are defined solely upon the notion of probabilistic conditional independence, these encouraging results do not take advantage of the more general probabilistic independencies recently proposed.

Abstract. In a cluster of many servers containing heterogeneous multimedia learning material and serving users with different backgrounds (e.g. language, interests, previous knowledge, hardware and connectivity) it may be difficult for the learners to find a piece of material which fit their needs. This is the case of the COLDEX project. Recommender systems have been used to help people sift through all the available information to find that most valuable to them. We propose a recommender system, which suggest multimedia learning material based on the learner's background preferences as well as the available hardware and software that he/she has. 1

Personal information agents have emerged in the last decade to help users to cope with the increasing amount of information available on the Internet. These agents are intelligent assistants that perform several information-related tasks such as finding, filtering and monitoring relevant information on behalf of users or communities of users. In order to provide personalized assistance, personal agents rely on representations of user information interests and preferences contained in user profiles. In this paper, we present a summary of the state-of-the-art in user profiling in the context of intelligent information agents. Existing approaches and lines of research in the main dimensions of user profiling, such as acquisition, learning, adaptation and evaluation, are discussed.

With the growth of the Web over the past years, there has been a similar increase in the services that are accessible over the Web. E-commerce, such on-line stores, is one of the most promising applications. Recommendation Systems are tools designed to help users to find items within a given domain, according to their own preferences, expressed by means of a user profile. A general model for recommendation systems based on Bayesian Networks is proposed in this paper. The model makes decisions about which items are the most useful for the user, carrying out the necessary computations in a very efficient way. 1

Like all men of the Library, I have travelled in my youth; I have wandered in search of a book, perhaps the catalogue of catalogues… The Library of Babel, Jorge Luis Borges In his short story "The Library of Babel", Jorge Luis Borges describes an unending library consisting of an