Design and implementation of architecture for multi-robot cooperation in the context of WSN

International audienceThe concept of autonomous mobile agents gets a lot of attention in the domain of wireless sensor networks (WSN) or wireless sensor and actuator networks (WSAN). Multiple robots that coordinate or cooperate with other sensors, robots or human operator, allow the WSN/WSAN to perform tasks that are far beyond the scope of single robot unit. In this work, we describe the robot middleware architecture that allows networked multi-robot control and data acquisition in the context of wireless sensor networks. Furthermore, we present three examples of robot network deployment and illustrate the proposed architecture usability: the robotic network deployment with the goal of covering the Point of Interest, adaptable multi-hop video transmission scenario, and the case of obtaining the energy consumption during the deployment

Multiple Target Discovery and Coverage with Mobile Wireless Sensors

International audienceEnvironmental monitoring has become a typical application of wireless sensor networks. The concept of monitoring certain points in the sensor field instead of the whole field area helps in reducing the costs of the deployment and improving the performance in terms of coverage. However, the problems of environment exploration, multiple target coverage and connectivity preservation are still solved separately and there are no works that combine the aforementioned problems into a single deployment scheme. In this work, we present a novel approach for mobile sensor deployment, where we combine the environment exploration with with network connectivity preservation and multiple target coverage. We examine the performance of our scheme through extensive simulation campaigns

Robust Wireless Sensor Network Deployment

International audienceIn this work we present a decentralized deployment algorithm for wireless mobile sensor networks focused on deployment Efficiency, connectivity Maintenance and network Reparation (EMR). We assume that a group of mobile sensors is placed in the area of interest to be covered, without any prior knowledge of the environment. The goal of the algorithm is to maximize the covered area and cope with sudden sensor failures. By relying on the locally available information regarding the environment and neighborhood, and without the need for any kind of synchronization in the network, each sensor iteratively chooses the next-step movement location so as to form a hexagonal lattice grid. Relying on the graph of wireless mobile sensors, we are able to provide the properties regarding the quality of coverage, the connectivity of the graph and the termination of the algorithm. We run extensive simulations to provide compactness properties of the deployment and evaluate the robustness against sensor failures. We show through the analysis and the simulations that EMR algorithm is robust to node failures and can restore the lattice grid. We also show that even after a failure, EMR algorithm call still provide a compact deployment in a reasonable time

Implementation of Survivor Detection Strategies Using Drones

Survivors stranded during floods tend to seek refuge on dry land. It is important to search for these survivors and help them reach safety as quickly as possible. The terrain in such situations however, is heavily damaged and restricts the movement of emergency personnel towards these survivors. Therefore, it is advantageous to utilize Unmanned Aerial Vehicles (UAVs) in cooperation with on-ground first responders to aid search and rescue efforts. In this article we demonstrate an implementation and improvement of the weight-based path planning algorithm using an off-the-shelf UAV. The coordinates of the survivor and their heading is reported by an on-ground observer to the UAV to generate a weighted map of the surroundings for exploration. Each coordinate in the map is assigned a weight which dictates the priority of exploration. These waypoints are then sorted on the basis of their weights to arrive at an ordered list for exploration by the UAV. We developed the model in MATLAB, followed by prototyping on Robot Operating System (ROS) using a 3DR Iris quadcopter. We tested the model on an off-the-shelf UAV by utilizing the MAVROS and MAVLINK capabilities of ROS. During the implementation of the algorithm on the UAV, several additional factors such as unreliable GPS signals and limited field of view which could effect the performance of the model were in effect, despite which the algorithm performed fairly well. We compared our model with conventional algorithms described in the literature, and showed that our implementation outperforms them.Comment: 22 pages, 42 figures, 2 table

Applications of Industrial Wireless Sensor Networks

International audienceThe collaborative nature of industrial wireless sensor networks (IWSNs) brings several advantages over traditional wired industrial monitoring and control systems, including self-organization, rapid deployment, flexibility, and inherent intelligent processing. In this regard, IWSNs play a vital role in creating more reliable, efficient, and productive industrial systems, thus improving companies' competitiveness in the marketplace. Industrial Wireless Sensor Networks: Applications, Protocols, and Standards examines the current state of the art in industrial wireless sensor networks and outlines future directions for research

Odabir autohtonih aromatičnih i ljekovitih trajnica za uređenje terapijskih urbanih prostora na Mediteranu

Kroz dugo vremensko razdoblje, aromatično, ljekovito, kao i začinsko bilje pronalazi svoju primjenu u različite svrhe. U novije vrijeme, kada raste svijest i potreba o sve većoj integraciji prirodnog okruženja u urbanoj sredini (biofilni dizajn), sve je aktualnije uređenje unutarnjih i vanjskih zelenih prostora s terapijskom i rehabilitacijskom namjenom. Aromatična i druga svojstva takvih biljaka potencijalnom prostoru dodaju novi aspekt (uz onaj dekorativni) u vidu jačanja motoričkih, senzoričkih, kognitivnih te socijalnih potencijala osjetljivih skupina posjetitelja, čime doprinose njihovom skladnijem životu i zdravlju. Specifičnim mirisima, raznolikošću oblika, struktura, boja i listova, ove biljke omogućuju višeosjetilni doživljaj uređenog prostora. S obzirom na svoje biološke značajke i ekološke zahtjeve, iziskuju različite stupnjeve njege i održavanja te ih u tom pogledu treba promišljeno odabrati i uklopiti u prostor koji se uređuje kako bi kontinuirano održavale svoju namjenu, kako u estetskom, tako i u terapijskom smislu, pružajući potpuni učinak za osjetila posjetitelja

Covering Points of Interest with Mobile Sensors

International audienceThe coverage of Points of Interest (PoI) is a classical requirement in mobile wireless sensor applications. Optimizing the sensors self-deployment over a PoI while maintaining the connectivity between the sensors and the base station is thus a fundamental issue. This article addresses the problem of autonomous deployment of mobile sensors that need to cover a predefined PoI with a connectivity constraint. In our algorithm, each sensor moves toward a PoI but has also to maintain the connectivity with a subset of its neighboring sensors that are part of the Relative Neighborhood Graph (RNG). The Relative Neighborhood Graph reduction is chosen so that global connectivity can be provided locally. Our deployment scheme minimizes the number of sensors used for connectivity thus increasing the number of monitoring sensors. Analytical results, simulation results and practical implementation are provided to show the efficiency of our algorithm

Spread and shrink: Point of interest discovery and coverage with mobile wireless sensors

International audienceIn this paper we tackle the problem of deploying mobile wireless sensors while maintaining connectivity with a sink throughout the deployment process. These mobile sensors should discover some points of interest (PoI) in an autonomous way and continuously report information from the observed events to the sink. Unlike previous works, we design an algorithm that uses only local information and local interactions with surrounding sensors. Moreover, unlike other approaches, our algorithm implements both the discovery and the coverage phase. In the discovery phase, the mobile sensors spread to discover new events all over the field and in the second phase, they shrink to concentrate only on the discovered events, named points of interest. We prove that connectivity is preserved during both phases and the spreading phase is terminated in a reasonable amount of time. Real experiments are conducted for small-scale scenarios that are used as a “proof of concept”, while extensive simulations are performed for more complex scenarios to evaluate the algorithm performance. A comparison with an existing work which uses virtual forces has been made as well. The results show the capability of our algorithm to scale fast in both discovery, coverage and shrinking phases

Recharging <i>vs</i>. Replacing Sensor Nodes Using Mobile Robots for Network Maintenance

International audienceWireless sensor networks (WSNs) have been of very high interest for the research community since years, but the quest for deploying a self-sustained network and effectively prolonging its lifetime has not found a satisfactory answer yet. Two main approaches can be identified that target this objective: either "recharging'' or "replacing'' the sensor nodes that are running out of energy. Of particular interest are solutions where mobile robots are used to execute the above mentioned tasks to automatically and autonomously maintain the WSN, thus reducing human intervention.Recently, the progress in wireless power transfer techniques has boosted research activities in the direction of battery recharging, with high expectations for its application to WSNs. Similarly, also sensor replacement techniques have been widely studied as a means to provide service continuity in the network. Objective of this paper is to investigate the limitations and the advantages of these two research directions. Key decision points must be identified for effectively supporting WSN self-maintenance: (i) which sensor nodes have to be recharged/replaced; (ii) in which order the mobile robot is serving (i.e., recharging/replacing) the nodes and by following which path; (iii) how much energy is delivered to a sensor when recharged. The influence that a set of parameters, relative to both the sensors and the mobile robot, on the decisions will be considered. Centralized and distributed solutions are compared in terms of effectiveness in prolonging the network lifetime and in allowing network self-sustainability. The performance evaluation in a variety of scenarios and network settings offers the opportunity to draw conclusions and to discuss the boundaries for one technique being preferable to the other