Nowadays, wireless sensor network (WSN) is becoming popular in various fields of different industries along with the rapid development of hardware and software. Whereas more and more WSN applications come into use has make it difficult for consumers especially those who do not have professional knowledge to use. So it is urgently necessary and significant to offer services which do not need professional knowledge to satisfy consumers’ requirements from the users’ point of view. Therefore, service oriented architecture (SOA) is introduced as a method to do our research from the users’ point of view. After asimple overall introduction of WSN which include the system architecture, hardware, software and supported technologies, we pay our emphasis on the power consumption modeling for WSN and get some formulations following the operation cycle. Last but not least, SOA method is analyzed and some SOA based WSN applications are introduced as examples to further understand of SOA based WSN for readers.

Wireless sensor networks (WSNs) groups specialized transducers that provide sensing services to Internet of Things (IoT) devices with limited energy and storage resources. Since replacement or recharging of batteries in sensor nodes is almost impossible, power consumption becomes one of the crucial design issues in WSN. Clustering algorithm plays an important role in power conservation for the energy constrained network. Choosing a cluster head (CH) can appropriately balance the load in the network thereby reducing energy consumption and enhancing lifetime. This paper focuses on an efficient CH election scheme that rotates the CH position among the nodes with higher energy level as compared to other. The algorithm considers initial energy, residual energy, and an optimum value of CHs to elect the next group of CHs for the network that suits for IoT applications, such as environmental monitoring, smart cities, and systems. Simulation analysis shows the modified version performs better than the low energy adaptive clustering hierarchy protocol by enhancing the throughput by 60%, lifetime by 66%, and residual energy by 64%.

Les réseaux de capteurs sont des réseaux particuliers composés d'objets contraints en ressources. Ils possèdent une faible puissance de calcul, une faible puissance de transmission, une faible bande passante, une mémoire de stockage limitée ainsi qu'une batterie à durée de vie limitée. Afin d'intégrer de tels réseaux dans l'internet des objects, de nouveaux protocoles ont été standardisés. Parmi ces protocoles, le protocole RPL (pour Routing Protocol for Low Power and Lossy Networks). Ce protocole est destiné a construire une topologie logique de routage appelée DODAG. Dans cette thèse, nous abordons l'aspect acheminement de données qui considère une topologie de routage arborescente. L'acheminement des données se fait donc de saut en saut d'un enfant à son parent (ou d'un parent à son enfant). Optimiser la construction du DODAG revient donc à construire un arbre couvrant selon une contrainte donnée. Un arbre couvrant est une structure communicante qui permet de maintenir un unique chemin entre toutes paires de noeuds tout en minimisant le nombre de liens de communication utilisés. De plus, nous considérons les contraintes des réseaux de capteurs telles qu'une batterie déchargée et la variabilité du lien radio comme des fautes transitoires. Ceci nous conduit par conséquent à construire une structure couvrante tolérante aux fautes transitoires. L'auto-stabilisation est une branche de l'algorithmique distribuée qui assure qu'à la suite d'une ou de plusieurs fautes transitoires, le système va retrouver de lui-même un comportement correcte au bout d'un temps fini. L'objectif de cette thèse est de proposer des algorithmes auto-stabilisants dédiés aux réseaux de capteurs. / Spanning Trees from theory to practiceSelf-Stabilizing algorithms and sensor networksAbstract : Sensor networks are composed of ressources constrained equipments. They have low computing power, low transmission power, low bandwidth, limited storage memory and limited battery life.In order to integrate such networks in the Internet of things, new protocols were standardized such as RPL protocol (for Routing Protocol for Low Power and Lossy Networks). This protocol is intended to build a logical routing topology called DODAG (for Destination Oriented Directed Acyclic Graph). In this thesis, we discuss the data routing aspect by considering a tree routing topology. Thus, the routing of data is hop by hop from a child to its parent (or from a parent to its child). Optimize the construction of the DODAG is therefore to build a spanning tree in a given constraint. A spanning tree is a connecting structure that maintains a unique path between all pairs of nodes while minimizing the number of used communication links. Furthermore, we consider the constraints of sensor networks, such as a dead battery and the variability of the radio link as transient faults. This leads us to build a covering structure tolerant to transient faults. The self-stabilization is a branch of distributed algorithms that ensures that following one or more transient faults, the system will find itself a correct behavior after a finite time.The objective of this thesis is to propose self-stabilizing algorithms dedicated to sensor networks. The contributions of this thesis are:In the first part of the thesis, we proposed a self-stabilizing algorithm for the construction of a minimum diameter spanning tree.This construction is natural when we want to minimize the communication delay between a root and all other network nodes. Our algorithm has several advantages. First, our algorithm is limited to memory occupation of O(log n) bits per node, reducing the previous result of an n factor while maintaining a polynomial convergence time. Then, our algorithm is the first algorithm for minimum diameter spanning tree that works as an unfair distribution demon. In other words, we make no restriction on the asynchronous network behavior. In the second part of the thesis, we are interested in the unstable topology built by RPL protocol (DODAG). Our solution is to place an additional constraint on the number of children a node can accept during the construction of the DODAG. This constraint has the effect of reducing the rate of parent change and consequently to improve the protocol performance in terms of packet delivery rate, delay of communication and power consumption. In addition, we implemented a mechanism to update the information of the downward routes in RPL. Furthermore, our solution has the advantage of not generating overhead because we use existing control messages provided by RPL to implement it. Finally, this contribution is twofold since we validated our solution both by simulations and experiments.

Les Réseaux de Capteurs Sans Fils (RCSFs) ont pris beaucoup d'importance dans plusieurs domaines tels que l'industrie, l'armée, la pollution atmosphérique etc. Les capteurs sont alimentés par des batteries qui ne sont pas faciles à remplacer surtout dans les environnements peu accessibles. L'énergie de chaque capteur est considérée comme la source première d'augmentation de la durée de vie des RCSFs. Puisque la transmission de données est plus coûteuse en consommation d'énergie, notre préoccupation première est de proposer une technique efficace de transmission des données de tous les capteurs vers le sink tout en réduisant la consommation en énergie. Nous suggérons trois trois algorithmes d'agrégation de données basé sur la construction d'arbres : Depth-First Search Aggregation (DFSA), Flooding Aggregation (FA) et Well-Connected Dominating Set Aggregation (WCDSA) qui permettront de réduire le nombre de transmissions de chaque capteur vers le sink. L'agrégation des données basée sur la construction d'arbres souffre du délai de délivrance de données parce que les parents doivent attendre de recevoir les données de leurs feuilles. Certains parents pourraient avoir beaucoup de feuilles, et il serait alors assez coûteux pour un parent de stocker toutes les données entrantes dans sa mémoire. Ainsi, nous devons déterminer le temps que chaque parent doit mettre pour agréger et traiter les données de ses feuilles. Nous proposons un algorithme, Efficient Tree-based Aggregation and Processing Time (ETAPT) qui utilise la métrique Appropriate Data Aggregation and Processing Time (ADAPT). Etant donné la durée 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'agrégation des données par les parents, il peut arriver que la quantité de données collectées soit très grande et dépasse la quantité de stockage maximale de données que peut contenir leurs mémoires. Nous proposons l'introduction dans le réseau de plusieurs collecteurs de données appelés Mini-Sinks (MSs). Ces MSs sont mobiles et se déplacent selon un modèle de mobilité aléatoire dans le réseau pour maintenir la connexité afin d'assurer la collecte contrôlée des données basée sur le protocole de routage Mulipath Energy Conserving Routing Protocol (MECRP). Les capteurs peuvent être équipés de plusieurs interfaces radios partageant un seul canal sans fil avec lequel ils peuvent communiquer avec plusieurs voisins. La transmission des données à travers une liaison de communication entre deux parents peut interférer avec les transmissions d'autres liaisons si elles transmettent à travers le même canal. Nous avons besoin de savoir quel canal utiliser en présence de plusieurs canaux pour une transmission donnée. Nous proposons une méthode distribuée appelée: Well Connected Dominating Set Channel Assignement (WCDS-CA), pour calculer le nombre de canaux qui seront alloués à tous les capteurs de telle sorte que les capteurs adjacents se voient attribués des canaux différents / 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 transports terrestres occupent une place majeure dans notre société, notamment en ville où les ralentissements aux heures de pointe peuvent avoir un impact notable sur l'organisation des activités, l'économie ou encore l'écologie. Les infrastructures routières sont généralement coordonnées par un centre de contrôle, responsable du maintien des équipements, de leurs réglages initiaux et de la gestion des incidents (matériels ou humains). Les nouvelles technologies de l'information et de la communication ont permis, en l'espace de quelques années, de mettre en œuvre des systèmes de transport intelligents. À l'aide de multiples points de mesures répartis sur le territoire, un opérateur peut dénombrer les usagers et en déduire la charge du réseau. Toutefois, centraliser les informations présente de nombreuses limites. Cette thèse vise à étudier l'emploi de systèmes distribués afin de mettre en œuvre des systèmes de transport intelligents grâce à un réseau de capteurs sans fil. Couplés à une unité de détection (p. ex., un magnétomètre), les capteurs communicants peuvent réagir au passage d'un véhicule en étant déployés, par exemple, sur les voies. Ils sont également capables de coopérer et de s'affranchir d'une entité centrale, rendant tout ou partie d'une zone urbaine totalement indépendante. D'autre part, ces réseaux peuvent fonctionner de manière autonome et tolèrent mieux les pannes, car aucun élément n'est indispensable au fonctionnement global du système. Enfin, les éléments de ces réseaux sont petits, peu coûteux, et communiquent en sans fil, ce qui leur permet d'être déployés et redéployés rapidement et de manière dense. / Road traffic has a significant effect on metropolitan activities, especially during peak hours when it impacts on areas such as the economy and the environment. Road infrastructure is typically coordinated from a control centre that is responsible for maintaining not only its equipment but also their initial settings and incident management (both material and human). During the past few years, new technologies in the fields of information and communication have led to the introduction of intelligent transportation systems. Using multiple measurement points distributed across a country, an operator can count road users and calculate the network load. However, the centralization of information has a number of drawbacks. The aim of this thesis is to study the use of distributed systems in order to implement intelligent transportation systems via a wireless sensor network. Coupled to a detection unit (e.g., a magnetometer), the interconnected sensors can respond to the passage of a vehicle when deployed, for example, along the road. They can also work together without recourse to a central entity - rendering all or part of an urban area totally independent. Furthermore, these networks can operate autonomously and are less susceptible to breadown, because the overall running of the system is not affected by the failure of individual components. Finally, components are small and cheap, and they operate wirelessly, which means they can be deployed and redeployed both rapidly and densely.

This diploma thesis deals with sensor networking technology, namely about ZigBee. This work consists of two parts - teoretical and practical. The teoretical part is created by some chapters which describe protocols and standards which compose a bases to ZigBee technology. Some parts of this chapter compare ZigBee network with the other wireless solutions and deals with their features. Practical parts is based on properties of available ZigBee devices and summarize communication among sensor network nodes,  own ZigBee application, application gateway design and its implementation for ZigBee network monitoring and control from Internet. The last chapter is devoted to discusion about problems and their solutions alternatively  about suggestions of next study and improvement this project.

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Data networks are an important part in an increasing number of applications with real-time and reliability requirements. To meet these demands a variety of approaches have been proposed. Forward error correction, which adds redundancy to the communicated data, is one of them. However, the redundancy occupies communication bandwidth, so it is desirable to control the amount of redundancy in order to achieve high reliability without adding excessive communication delay. The main contribution of the thesis is to formulate the problem of adjusting the redundancy in a control framework, which enables the dynamic properties of error correction control to be analyzed using control theory. The trade-off between application quality and resource usage is captured by introducing an optimal control problem. Its dependence on the knowledge of the network state at the transmission side is discussed. An error correction controller that optimizes the amount of redundancy without relying on network state information is presented. This is achieved by utilizing an extremum seeking control algorithm to optimize the cost function. Models with varying complexity of the resulting feedback system are presented and analyzed. Conditions for convergence are given. Multiple-input describing function analysis is used to examine periodic solutions. The results are illustrated through computer simulations and experiments on a wireless sensor network. / QC 20101105

Massive deployment of wireless IoT (Internet of Things) devices makes replacement or recharge of batteries expensive and impractical for some applications. Energy harvesting is a promising solution, and various designs are proposed to harvest power from ambient resources including thermal, vibrational, solar, wind, and RF sources. Among these ambient resources, AC powerlines are a stable energy source in an urban environment. Many researchers investigated methods to exploit this stable source of energy to power wireless IoT devices. The proposed circuit aims to harvest energy from AC powerlines with a wide input range of from 10 to 50 A. The proposed system includes a wake-up circuit and is capable of cold-start. A buck-boost converter operating in DCM is adopted for impedance matching, where the impedance is rather independent of the operation conditions. So, the proposed system can be applied to various types of wireless sensor nodes with different internal impedances. Experimental results show that the proposed system achieves an efficiency of 80.99% under the powerline current of 50 A. / M.S. / Nowadays, with the magnificent growth of IoT devices, a reliable, and efficient energy supply system becomes more and more important, because, for some applications, battery replacement is very expensive and sometimes even impossible. At this time, a well-designed self-contained energy harvesting system is a good solution. The energy harvesting system can extend the service life of the IoT devices and reduce the frequency of charging or checking the device. In this work, the proposed circuit aims to harvest energy from the AC power lines, and the harvested power intends to power wireless sensor nodes (WSNs). By utilizing the efficient and self-contained EH system, WSNs can be used to monitor the temperature, pressure, noise level and humidity etc. The proposed energy harvesting circuit was implemented with discrete components on a printed circuit board (PCB). Under a power line current of 50 A @ 50 Hz, the proposed energy harvesting circuit can harvest 156.6 mW, with a peak efficiency of 80.99 %.

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