L'arrivée du WiFi, technologie de télécommunication radio

National audienceLa technologie radio 802.11, désormais bien connue sous le nom de Wi-Fi, est développée à la fin des années 1990, mais sa mise en oeuvre est assez compliquée et il faudra attendre les années 2002-2003 pour que les vraies cartes Wi-Fi arrivent sur le marché et ouvrent le champ des applications d'objets mobiles communicants

Messages with Implicit Destinations as Mobile Agents

International audienceApplications running over decentralized systems, distribute their computation on nodes/agents, which exchange data and services through messages. In many cases, the provenance of the data or service is not relevant, and applications can be optimized by choosing the most efficient solution to obtain them. We introduce a frameworkwhich allows messages with intensional destination, which can be seen as restricted mobile agents, specifying the desired service but not the exact node that carries it, leaving to the system the task of evaluating the extensional destination, that is an explicit address for that service. The intensional destinations are defined using queries that are evaluated by other agents while routing. We introduce the Questlog language, which allows to reformulate queries, and express complex strategies to pull distributed data. In addition, intensional addresses offer persistency to dynamic systems with nodes/agents leaving the system. We demonstrate the approach with examples taken from sensor networks, and show some experimental results on the QuestMonitor platform

The KAA project: a trust policy point of view

In the context of ambient networks where each small device must trust its neighborhood rather than a fixed network, we propose in this paper a \textit{trust management framework} inspired by known social patterns and based on the following statements: each mobile constructs itself a local level of trust what means that it does not accept recommendation by other peers, and the only relevant parameter, beyond some special cases discussed later, to evaluate the level of trust is the number of common trusted mobiles. These trusted mobiles are considered as entries in a local database called history for each device and we use identity-based cryptography to ensure strong security: history must be a non-tansferable object

Trusted Ambient community for self-securing hybrid networks

An ad-hoc network is a group of wireless terminals that possess the ability to automatically organise themselves into a radio network, in which each terminal can perform the duties of both end node as well as router. A network so formed has the particular characteristics of being dynamic by nature, being inherently incapable of relying on any pre-existing infrastructure or centralised administration system as well as being unique in that it uses Hertzian transmission with air as its medium. This ad hoc communication capacity, together with multi technology support and more classical cellular access to networks - or to the Internet - is the fundamental network architecture for what is nowadays called . This architecture is sometimes denoted hybrid networks. These are the characteristics that render hybrid networks particularly vulnerable to attack. The security models employed in other infrastructure based networks (wireless or otherwise) are inapplicable in ad hoc networks, due to their design based on the fundamental principle of a reliable, fixed trusted third party or an established addressing system. We propose, in this paper, a solution that addresses the specific needs of ad hoc networks. First, we describe the paradox presented by the contrasting needs for mobility as well as strong security in ad hoc / hybrid networks. Second we describe our proposed solution, a , which uses the concept of trust transmission to form a mobile version of an infrastructure: an . As the ambient community grow in terms of members, the trust seed becomes capable of distributing trust to more and more entities. However, the originality of our contribution resides in the proposition of a new key agreement protocol, conceived to distribute a secret between ad-hoc nodes without ever transmitting it via a non-secure channel, and without any prior configuration. We conclude the document by presenting some perspectives that will allow us to further our work and approach the concept of adaptive trust and ambiances

Formal QoS Validation Approach on a Real-Time MAC Protocol for Wireless Sensor Networks

Several wireless sensor network applications are currently popping up, in various domains. Their goal is often to monitor a geographic area. When a sensor detects a monitored event, it informs a sink node using alarm messages. The area surveillance application needs to react to such an event with a finite, bounded and known delay: these are real-time constraints. The network being linear, routing becomes unnecessary. This work proposes a new real-time MAC protocol with realistic assumptions on sensor networks. We present a formal validation of this protocol, and explicit the worst case times for the services offered by the protocol (initialization and alarm transmission using different modes)

Radio Network Planning with Combinatorial Optimization Algorithms

International audienceFuture UMTS radio planning engineers will face difficult problems due to the complexity of the system and the size of these networks. In the STORMS project, a software for the optimisation of the radio network is under development. Two mathematical models of the radio planning problem are proposed. Two software prototypes based on these models are described with the first experimental and comparative results

A parallel thinning algorithm using the bounding boxes technique

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Ad hoc networks: principles and routing

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A parallel thinning algorithm using the bounding boxes technique

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Pyramidal thinning algorithm for SMID parallel machines

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