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Résumé: Dans cet article, nous portons notre regard sur l'aide à la décision du point de vue des systèmes décisionnels au sens des entrepôts de données et de l'analyse en ligne. Après avoir défini les concepts qui sous-tendent ces systèmes, nous nous proposons d'aborder les problématiques de recherche qui leur sont liées selon quatre points de vue : les données, les environnements de stockage, les utilisateurs et la sécurité. Nous abordons finalement les problèmes qui restent ouverts dans le domaine des entrepôts de données.

Résumé: Twitter have become a significant means by which people communicate with the world and describe their current activities, opinions and status in short text snippets. Tweets can be analyzed automatically in order to derive much potential information such as, interesting topics, social influence, user's communities, etc. Extraction communities within social networks has been a focus of recent work in several areas. Different from the most community discovery methods focused on the relations between users, we aim to derive user's communities based on common topics from user's tweets. For instance, if two users always talk about politic in their tweets, thus they can be grouped in the same community which is related to politic topic. To achieve this goal, we propose a new approach called CETD: Community Extraction based on Topic-Driven-Model. This approach combines our proposed model used to detect topics of the user's tweets based on a semantic taxonomy together with a community extraction method based on the hierarchical clustering technique. Our experimentation on the proposed approach shows the relevant of the users communities extracted based on their common topics and domains.

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Résumé: This work proposes a modeling for providing a Multi Agents System (MAS) based decision tool in case of pandemics with the objective to preserve vital functions of society while containing the pandemics. Some works integrate people behaviors in their daily life to get a more realistic model for simulation. They mainly use a mathematical modeling based on random graphs for handling social network concept. However, that modeling suers of a major inconvenience: social relationships are modeled only by one undirected graph which does not sounds realistic. Our approach consists in generalizing random graphs by stochastic pretopology. Stochastic pretopology concepts are then inserted in a MAS coupled with a Geographical Information System (GIS).We are thus able to deal with spatial information and directly run simulations on georeferenced data. Such simulations provide usefull results for the decision making concerning healthcare system management.

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Résumé: BELMANDT is the collective pseudonym under which a group of mathematicians and computer scientists have decide to publish their common works on Pretopology and to give a nod to BOURBAKI. These works would never have been realized without the dynamic leadership of professor Marcel Brissaud, now retired, and who is of course associated to the publication of this book. Marcel Brissaud, during the seventies, has been the first to observe the interest of developing mathematical concepts adapted to humanities. Pretopology theory relies on the statement that the axiomatic of mathematical topology is too strong to model the phenomena of social sciences. This axiomatic has to be reconsidered to give birth to a theory that is adapted to data issued from these fields of expertise, better than trying to force data to fit to an existing and inadequate theory. This book is the first English revised version of a first book, published in French, which is planned to be the first of a series dedicated to the whole set of results obtained in Pretopology: continuity, connectedness, associated metric... Many applications of Pretopology were conducted in various fields: economy with the structural analysis of a economy, game theory with the study of the dynamics of coalitions in cooperative games, sociology with analysis of social networks, data analysis with the construction of clustering algorithms, pattern recognition with digital image analysis as in mathematical morphology, etc. Purely mathematical work in Pretopology has enabled the building of processing algorithms that have been put in a software library, PRETOPOLIB, allowing researchers to implement a pretopological approach in their work. We wish the reader of this book the pleasure of exploring the basics of Pretopology and we hope that he will find the materials for his own work and we give him a rendezvous for the next books on the subject.