André Lagreze

Towards a monitoring system for High Altitude Objects

High Altitude Objects (HAO), typically sounding balloons, are mobile objects that gather information (e.g. weather data) during their trip and send it to base stations using wireless communication. Once launched, these objects need to be tracked and recovered, and ideally monitored to exploit data in real-time. This paper discusses about middleware and embedded system concerns when monitoring such objects. The architecture that is presented in the following relies on both a monitoring middleware based on a modified RFID suite (part of the OW2 Aspire project, primarily targeting the management of objects in an Internet of Things for RFID-based and sensor-based applications), and on an embedded system (part of the HAO) with multimodal communication capabilities. This approach has been validated by two experiments consisting in a real time monitoring of a sounding balloon. The whole application is generic enough to be used to track and monitor other kinds of mobile objects, including sounding rockets and Unmanned Aerial Vehicles (UAVs).

A Multi-Cooperative-Based Approach to Manage Communication in Wireless Instrumentation Systems

Wireless instrumentation systems are a collection of resource-constrained nodes in charge of sensing, processing, and transmitting data. They are often battery powered, and consequently, subject to energy constraints. Since communication is the most energy-consuming task, efforts have to be made during the routing process in order to maximize the network lifespan and avoid network partitioning. In this context, the multi-wireless-agent communication (MWAC) model provides a self-organization process for managing communication in this kind of instrumentation system. Given an organization and a node, MWAC determines a single path to route messages to the destination. This may cause congestions for large data flows. This paper introduces antMWAC, a model designed to improve MWAC. Ant colony optimization is used to balance the traffic load on wireless nodes and insure a multipath routing. Ants interact with nodes to make the communication more efficient. The cooperation between them is increased to find a tradeoff between new path discovering and path reinforcement. The aim is to allow the nodes exploiting the information routed by ants and modifying ant decision parameters. Experiments show that antMWAC diversifies the nodes participating in routing operations, reducing node congestion.

Landslide prevention using a buried sensor network

Landslides, of slip/cast type, dynamics are mainly characterised by a sudden solid to fluid transitioning during heavy rain events. This feature makes them rather difficult to predict and therefore remains a major threat to nearby populated valleys. This paper aims at developing a new predictive system which analyses field movements using sensors. The idea is to use a sensor network to instrument unstable slopes. Other monitoring techniques can be used for this particular phenomenon (photogrammetry, LIDAR ...), but some significant imperfections and flaws lay within their usage. This paper presents our system characterized by its low consumption and cost, in order to achieve continuous monitoring of the overall shape deformation. The second part of the paper presents the methods used to enable geolocation using LoRa (Long Range) radio transmission technology..

Signal-to-noise ratio for irrigation canal networked control system (MSC'2015)

In this paper, we consider the problem of progressive increase in the channel Signal-to-Noise ratio (SNR) requirements due to the control chain as seen in some configurations of irrigation canal control. At first, the admissible SNRs required for system constraints will be discussed and then the limitation will be set out. We demonstrate that this SNR limitation can be reduced by the design of control system with feed-forward control added to feedback loop in downstream and upstream configurations. As a result, the SNR factor can be considered as one of criterion when choosing different locations of controllers compared to those of feedback sensors and controlled actuators, towards satisfying communication constraints. That makes the analysis and design of a networked control systems easier in terms of communication reliability and efficient bandwidth allocation. The practitioners will find it helpful about the best configuration for the controller position and related communication channels in a irrigation canal setting, as to reduce the SNR requirements whilst satisfying the original control performance requirements. Simulations are presented for downstream and upstream control configurations using a standard feedback control loop first, and then a feedback control loop with added networked feed-forward control for disturbance attenuation.

A Decentralized Self-Organized Approach for Wireless Sensor Networks

This paper deals with an application of multiagent systems to management in wireless sensor networks (WSN). This WSN will be applied to monitor an underground hydrographic network (the EnvSys project). We present the EnvSys project, the multiagent systems (MAS) and their application in WSN. After we propose an adaptive infrastructure of autonomous agents to route the information in the best way, in consideration to strong constraints on energy resources. Interesting simulation results are discussed.

Integrated environment for automotive multisensor data fusion system

This paper describes an approach we used for designing an automotive obstacle detection system. This system will be able to detect hazardous situations in road traffic by the data fusion of a set of sensors and to warn the driver when such situations occur. Our approach can be summarized in three points: (1) We used a distributed architecture of smart sensors which are binded by a dedicated data network. (2) Since the experiments on a test tack are often difficult, our system makes possible the recording of all sensor data, through the network, in real time. These data are time stamped and digital video images are also recorded at a frequency of 2 Hz. Then, it becomes possible to make long recording sessions of different road scenarios and to have a pool of data at our disposal for testing and validating obstacle detection algorithms. (3) We use a classification of the sensors to make connection of new sensors to the network easier.