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Databases are hosted by a growing number of lightweight intelligent devices like palmtops, cellular phones, car computers and even smart cards. Mobility and disconnected computing are two major issues in such environment. This paper deals with the way databases can be exploited in this context while maintaining a strong transactional coherency. More(More)
Smartcards are the most secure portable computing device today. They have been used successfully in applications involving money, and proprietary and personal data (such as banking, healthcare, insurance, etc.). As smartcards get more powerful (with 32-bit CPU and more than 1 MB of stable memory in the next versions) and become multi-application, the need(More)
The democratization of ubiquitous computing (access data anywhere, anytime, anyhow), the increasing connection of corporate databases to the Internet and the today's natural resort to Web-hosting companies strongly emphasize the need for data confidentiality. Database servers arouse user's suspicion because no one can fully trust traditional security(More)
Smartcards are the most secure portable computing device today. They have been used successfully in applications involving money, proprietary and personal data (such as banking, healthcare, insurance, etc.). As smartcards get more powerful (with 32 bit CPU and more than 1 MB of stable memory in the next versions) and become multi-application, the need for(More)
1 Although widely used in distributed transactional systems, the so-called Two-Phase Commit (2PC) protocol introduces a substantial delay in transaction processing, even in the absence of failures. This has led several researchers to look for alternative commit protocols that minimize the time cost associated with coordination messages and forced log writes(More)
Discovery of association rules is an important problem in Data Mining. The classical approach is to generate all itemsets that have support (i.e., the fraction of transactions containing the itemset) above a user given threshold. Most existing algorithms aim at reducing the number of scans over the transaction database, i.e., the I/O overhead. We consider(More)
NAND Flash has become the most popular stable storage medium for embedded systems. As on-board storage capacity increases, the need for efficient indexing techniques arises. Such techniques are very challenging to design due to a combination of NAND Flash constraints (for example the block-erase-before-page-rewrite constraint and limited number of erase(More)
Ce document est le résultat d'un travail collectif réalisé par les membres de l'action spécifique CNRS « Mobilité/Accès aux données ». Il fait le point sur l'état d'avancement des travaux réalisés dans le domaine des bases de données mobiles et identifie quelques orientations de recherche jugées particulièrement pertinentes. Compte tenu de la largeur du(More)
The erosion of trust put in traditional database servers and in Database Service Providers, the growing interest for different forms of data dissemination and the concern for protecting children from suspicious Internet content are different factors that lead to move the access control from servers to clients. Several encryption schemes can be used to serve(More)
Pervasive computing introduces data management requirements that must be tackled in a growing variety of lightweight computing devices. Personal folders on chip, networks of sensors and data hosted by autonomous mobile computers are different illustrations of the need for evaluating queries confined in hardware constrained computing devices. RAM is the most(More)