Modelling Trust In Wireless Sensor Networks from the Sensor Reliability Prospective

This paper surveys the state of the art trust-based systems in Wireless Sensor Networks (WSN); it highlights the difference between Mobile ad hoc networks (MANET) and WSN and based on this observed difference (monitoring events and reporting data) a new trust model is introduced, which takes sensor reliability as a component of trust. A new definition of trust is created based on the newly introduced component of trust (sensor data) and an extension of node misbehaviour classification is also presented based on this new component of trust

RBATMWSN: Recursive Bayesian approach to trust management in wireless sensor networks

This paper introduces a new trust model and a reputation system for wireless sensor networks based on a sensed continuous data. It establishes the continuous version of the beta reputation system introduced in [1] and applied to binary events and presents a new Gaussian Reputation System for Sensor Networks (GRSSN) . We introduce a theoretically sound Bayesian probabilistic approach for mixing second-hand information from neighbouring nodes with directly observed information. ©2007 IEEE

Genome-Wide Linkage in a Highly Consanguineous Pedigree Reveals Two Novel Loci on Chromosome 7 for Non-Syndromic Familial Premature Ovarian Failure

BACKGROUND: The human condition known as Premature Ovarian Failure (POF) is characterized by loss of ovarian function before the age of 40. A majority of POF cases are sporadic, but 10-15% are familial, suggesting a genetic origin of the disease. Although several causal mutations have been identified, the etiology of POF is still unknown for about 90% of the patients.¦METHODOLOGY/PRINCIPAL FINDINGS: We report a genome-wide linkage and homozygosity analysis in one large consanguineous Middle-Eastern POF-affected family presenting an autosomal recessive pattern of inheritance. We identified two regions with a LOD(max) of 3.26 on chromosome 7p21.1-15.3 and 7q21.3-22.2, which are supported as candidate regions by homozygosity mapping. Sequencing of the coding exons and known regulatory sequences of three candidate genes (DLX5, DLX6 and DSS1) included within the largest region did not reveal any causal mutations.¦CONCLUSIONS/SIGNIFICANCE: We detect two novel POF-associated loci on human chromosome 7, opening the way to the identification of new genes involved in the control of ovarian development and function

Distributed Recursive Algorithm for Auto Calibration in Drift Aware Wireless Sensor Networks

The purpose for wireless sensor networks is to deploy low cost sensors with sufficient computing and communication capabilities to support networked sensing applications. The emphasis on lower cost led to sensors that are less accurate and less reliable than their wired sensor counterparts. Sensors usually suffer from both random and systematic bias problems. Even when the sensors are properly calibrated at the time of their deployment, they develop drift in their readings leading to biased sensor measurements. The drift in this context is defined as a unidirectional long-term change in the sensor measurement. We assume that neighboring sensors have correlated measurements and that the instantiation of drift in a sensor is uncorrelated with other sensors. As an extension of our results in [1], and inspired by the resemblance of registration problem in radar target tracking, we propose a distributed recursive Bayesian algorithm for auto calibration of wireless sensors in the presence of slowly varying drifts. The algorithm detects and corrects sensor drifts and improves the reliability and the effective life of the network

Estimating the Number of People in Buildings Using Visual Information

Real time pedestrian flow information and the count of people in determined areas is essential for a multitude of management and monitoring functions. The range of applications is wide and the focus here is on the development of statistical methods for people volume estimation in buildings. To count people, visual information from surveillance cameras is used. This is the first of a series of reports, where the problem is divided in estimation classes of increasing difficulty. In the initial stage, probability models are derived for the basic counting scenario, using data gathered from a single camera. The methodology is extended to more complex problems, making use of several cameras covering the same field of view. The consideration of all possible classes of estimation problems leads to solutions that culminate in the assessment of the total number of people in a building

Damage Analysis in 3D Woven SiC/SiC Ceramic Matrix Composite

International audienc

Suivi de l’endommagement en fatigue d’un composite à renfort interlock carbone/époxy par émission acoustique

L’émission acoustique est une technique qui a déjà prouvé son utilité dans le suivi des endommagements d’un composite. Dans cette étude, cette technique est appliquée à des essais de fatigue sur un composite interlock. Dans un premier temps, cette étude présente les signaux rencontrés lors d’un essai de traction uni-axiale. L’accent est porté ensuite sur le traitement des signaux acoustiques qui doit nous permettre de mieux appréhender les phénomènes responsables des pertes de propriété du matériau. L’originalité première de cette étude réside dans la distinction de deux branches lors de la représentation de l’énergie de chaque événement en fonction du nombre de coups. Ces deux branches sont attribuées pour la première aux phénomènes de rupture de fibres, déchaussements, qu’on retrouve sur un essai statique, tandis que la deuxième correspond aux phénomènes de fatigue, notamment les frottements, mais aussi des dommages plus importants tels que des micro-flambements locaux. Ce papier s’intéresse ensuite à attribuer le rôle de chaque branche dans la perte de propriétés mécaniques du matériau