162 research outputs found

    Agrégation et routage efficace de données dans les réseaux de capteurs sans fils

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    Wireless Sensor Networks (WSNs) have gained much attention in a large range of technical fields such as industrial, military, environmental monitoring etc. Sensors are powered by batteries, which are not easy to replace in harsh environments. The energy stored by each sensor is the greatest impediment for increasing WSN lifetime. Since data transmission consumes more energy, our major concern is how to efficiently transmit the data from all sensors towards a sink. We suggest three tree-based data aggregation algorithms: Depth-First Search Aggregation (DFSA), Flooding Aggregation (FA) and Well-Connected Dominating Set Aggregation (WCDSA) to reduce the number of transmissions from each sensor towards the sink. Tree-based data aggregation suffers from increased data delivery time because the parents must wait for the data from their leaves. Some parents might have many leaves, making it very expensive for a parent to store all incoming data in its buffer. We need to determine the aggregation time each parent in the tree has to spend in aggregating and processing the data from its leaves. We propose an Efficient Tree-based Aggregation and Processing Time (ETAPT) algorithm using Appropriate Data Aggregation and Processing Time (ADAPT) metric. Given the maximum acceptable latency, ETAPT's algorithm takes into account the position of parents, their number of leaves and the depth of the tree, in order to compute an optimal ADAPT time. At any time, the amount of data aggregated by parents may become greater than the amount of data that can be forwarded. We propose the introduction into the network of many data aggregators called Mini-Sinks (MSs). MSs are mobile and move according to a random mobility model inside the sensor field to maintain the fully-connected network in order to aggregate the data based on the controlled Multipath Energy Conserving Routing Protocol (MECRP). Sensors may use many radio interfaces sharing a single wireless channel, which they may use to communicate with several neighbours. Two sensors operating on the same wireless channel may interfere with each other during the transmission of data. We need to know which channel to use in the presence of multiple channels for a given transmission. We propose a distributed Well-Connected Dominating Set Channel Assignment (WCDS-CA) approach, in which the number of channels that are needed over all sensor nodes in the network in such a way that adjacent sensor nodes are assigned to distinct channels.Les RĂ©seaux de Capteurs Sans Fils (RCSFs) ont pris beaucoup d'importance dans plusieurs domaines tels que l'industrie, l'armĂ©e, la pollution atmosphĂ©rique etc. Les capteurs sont alimentĂ©s par des batteries qui ne sont pas faciles Ă  remplacer surtout dans les environnements peu accessibles. L'Ă©nergie de chaque capteur est considĂ©rĂ©e comme la source premiĂšre d'augmentation de la durĂ©e de vie des RCSFs. Puisque la transmission de donnĂ©es est plus coĂ»teuse en consommation d'Ă©nergie, notre prĂ©occupation premiĂšre est de proposer une technique efficace de transmission des donnĂ©es de tous les capteurs vers le sink tout en rĂ©duisant la consommation en Ă©nergie. Nous suggĂ©rons trois trois algorithmes d'agrĂ©gation de donnĂ©es basĂ© sur la construction d'arbres : Depth-First Search Aggregation (DFSA), Flooding Aggregation (FA) et Well-Connected Dominating Set Aggregation (WCDSA) qui permettront de rĂ©duire le nombre de transmissions de chaque capteur vers le sink. L'agrĂ©gation des donnĂ©es basĂ©e sur la construction d'arbres souffre du dĂ©lai de dĂ©livrance de donnĂ©es parce que les parents doivent attendre de recevoir les donnĂ©es de leurs feuilles. Certains parents pourraient avoir beaucoup de feuilles, et il serait alors assez coĂ»teux pour un parent de stocker toutes les donnĂ©es entrantes dans sa mĂ©moire. Ainsi, nous devons dĂ©terminer le temps que chaque parent doit mettre pour agrĂ©ger et traiter les donnĂ©es de ses feuilles. Nous proposons un algorithme, Efficient Tree-based Aggregation and Processing Time (ETAPT) qui utilise la mĂ©trique Appropriate Data Aggregation and Processing Time (ADAPT). Etant donnĂ© la durĂ©e maximale acceptable, l'algorithme ETAPT prend en compte la position des parents, le nombre de feuilles et la profondeur de l'arbre pour calculer l'ADAPT optimal. A n'importe quel moment pendant l'agrĂ©gation des donnĂ©es par les parents, il peut arriver que la quantitĂ© de donnĂ©es collectĂ©es soit trĂšs grande et dĂ©passe la quantitĂ© de stockage maximale de donnĂ©es que peut contenir leurs mĂ©moires. Nous proposons l'introduction dans le rĂ©seau de plusieurs collecteurs de donnĂ©es appelĂ©s Mini-Sinks (MSs). Ces MSs sont mobiles et se dĂ©placent selon un modĂšle de mobilitĂ© alĂ©atoire dans le rĂ©seau pour maintenir la connexitĂ© afin d'assurer la collecte contrĂŽlĂ©e des donnĂ©es basĂ©e sur le protocole de routage Mulipath Energy Conserving Routing Protocol (MECRP). Les capteurs peuvent ĂȘtre Ă©quipĂ©s de plusieurs interfaces radios partageant un seul canal sans fil avec lequel ils peuvent communiquer avec plusieurs voisins. La transmission des donnĂ©es Ă  travers une liaison de communication entre deux parents peut interfĂ©rer avec les transmissions d'autres liaisons si elles transmettent Ă  travers le mĂȘme canal. Nous avons besoin de savoir quel canal utiliser en prĂ©sence de plusieurs canaux pour une transmission donnĂ©e. Nous proposons une mĂ©thode distribuĂ©e appelĂ©e: Well Connected Dominating Set Channel Assignement (WCDS-CA), pour calculer le nombre de canaux qui seront allouĂ©s Ă  tous les capteurs de telle sorte que les capteurs adjacents se voient attribuĂ©s des canaux diffĂ©rent

    Wireless multimedia sensor networks, security and key management

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    Wireless Multimedia Sensor Networks (WMSNs) have emerged and shifted the focus from the typical scalar wireless sensor networks to networks with multimedia devices that are capable to retrieve video, audio, images, as well as scalar sensor data. WMSNs are able to deliver multimedia content due to the availability of inexpensive CMOS cameras and microphones coupled with the significant progress in distributed signal processing and multimedia source coding techniques. These mentioned characteristics, challenges, and requirements of designing WMSNs open many research issues and future research directions to develop protocols, algorithms, architectures, devices, and testbeds to maximize the network lifetime while satisfying the quality of service requirements of the various applications. In this thesis dissertation, we outline the design challenges of WMSNs and we give a comprehensive discussion of the proposed architectures and protocols for the different layers of the communication protocol stack for WMSNs along with their open research issues. Also, we conduct a comparison among the existing WMSN hardware and testbeds based on their specifications and features along with complete classification based on their functionalities and capabilities. In addition, we introduce our complete classification for content security and contextual privacy in WSNs. Our focus in this field, after conducting a complete survey in WMSNs and event privacy in sensor networks, and earning the necessary knowledge of programming sensor motes such as Micaz and Stargate and running simulation using NS2, is to design suitable protocols meet the challenging requirements of WMSNs targeting especially the routing and MAC layers, secure the wirelessly exchange of data against external attacks using proper security algorithms: key management and secure routing, defend the network from internal attacks by using a light-weight intrusion detection technique, protect the contextual information from being leaked to unauthorized parties by adapting an event unobservability scheme, and evaluate the performance efficiency and energy consumption of employing the security algorithms over WMSNs

    Smart Wireless Sensor Networks

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    The recent development of communication and sensor technology results in the growth of a new attractive and challenging area - wireless sensor networks (WSNs). A wireless sensor network which consists of a large number of sensor nodes is deployed in environmental fields to serve various applications. Facilitated with the ability of wireless communication and intelligent computation, these nodes become smart sensors which do not only perceive ambient physical parameters but also be able to process information, cooperate with each other and self-organize into the network. These new features assist the sensor nodes as well as the network to operate more efficiently in terms of both data acquisition and energy consumption. Special purposes of the applications require design and operation of WSNs different from conventional networks such as the internet. The network design must take into account of the objectives of specific applications. The nature of deployed environment must be considered. The limited of sensor nodesïżœ resources such as memory, computational ability, communication bandwidth and energy source are the challenges in network design. A smart wireless sensor network must be able to deal with these constraints as well as to guarantee the connectivity, coverage, reliability and security of network's operation for a maximized lifetime. This book discusses various aspects of designing such smart wireless sensor networks. Main topics includes: design methodologies, network protocols and algorithms, quality of service management, coverage optimization, time synchronization and security techniques for sensor networks

    Proceedings of the Third Edition of the Annual Conference on Wireless On-demand Network Systems and Services (WONS 2006)

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    Ce fichier regroupe en un seul documents l'ensemble des articles accéptés pour la conférences WONS2006/http://citi.insa-lyon.fr/wons2006/index.htmlThis year, 56 papers were submitted. From the Open Call submissions we accepted 16 papers as full papers (up to 12 pages) and 8 papers as short papers (up to 6 pages). All the accepted papers will be presented orally in the Workshop sessions. More precisely, the selected papers have been organized in 7 session: Channel access and scheduling, Energy-aware Protocols, QoS in Mobile Ad-Hoc networks, Multihop Performance Issues, Wireless Internet, Applications and finally Security Issues. The papers (and authors) come from all parts of the world, confirming the international stature of this Workshop. The majority of the contributions are from Europe (France, Germany, Greece, Italy, Netherlands, Norway, Switzerland, UK). However, a significant number is from Australia, Brazil, Canada, Iran, Korea and USA. The proceedings also include two invited papers. We take this opportunity to thank all the authors who submitted their papers to WONS 2006. You helped make this event again a success

    Actas da 10ÂȘ ConferĂȘncia sobre Redes de Computadores

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    Universidade do MinhoCCTCCentro AlgoritmiCisco SystemsIEEE Portugal Sectio

    AI and IoT Meet Mobile Machines

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    Infrastructure construction is society's cornerstone and economics' catalyst. Therefore, improving mobile machinery's efficiency and reducing their cost of use have enormous economic benefits in the vast and growing construction market. In this thesis, I envision a novel concept smart working site to increase productivity through fleet management from multiple aspects and with Artificial Intelligence (AI) and Internet of Things (IoT)

    AI and IoT Meet Mobile Machines: Towards a Smart Working Site

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    Infrastructure construction is society's cornerstone and economics' catalyst. Therefore, improving mobile machinery's efficiency and reducing their cost of use have enormous economic benefits in the vast and growing construction market. In this thesis, I envision a novel concept smart working site to increase productivity through fleet management from multiple aspects and with Artificial Intelligence (AI) and Internet of Things (IoT)
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