Στη παρούσα διπλωματική εργασία ασχολούμαστε με την ανάπτυξη τεχνικών για υλοποίηση ενός κατανεμημένου φίλτρου Kalman σε ένα Δίκτυο Αισθητήρων (WSN). Τα δίκτυα αυτά έχουν γνωρίσει τα τελευταία χρόνια ραγδαία ανάπτυξη λόγω των εξαιρετικά πολλών εφαρμογών τους σε διάφορα πεδία της ανθρώπινης δραστηριότητας. Το πρόβλημα που πραγματευόμαστε εδώ είναι η προσπάθεια εκτίμησης της κατάστασης μιας στοχαστικής διαδικασίας που επιτηρείται-παρακολουθείται απο το δίκτυο. Οι κόμβοι-αισθητήρες που συναπαρτίζουν αυτά τα δίκτυα έχουν συνήθως περιορίσμενες δυνατότητες ¨αίσθησης¨, πράγμα που σημαίνει ότι κάθε μεμονωμένος κόμβος αδυνατεί να παράξει μια καλή εκτίμηση της κατάστασης. Διάφορες τεχνικές εχούν προταθεί για την επίλυση τέτοιου είδους προβλημάτων όπως το κεντρικό Φίλτρο Kalman ή διάφορες αποκεντρωμένες προσεγγίσεις, οι οποιές είχαν όμως υψηλό υπολογιστικό κόστος και τις καθιστούσαν πρακτικά μη υλοποιήσιμες, ειδικά για δίκτυα με μεγάλο αριθμό κόμβων. Έτσι στη παρούσα εργασία , χρησιμοποιώντας ως εργαλείο την θεώρια των αλγορίθμων ¨Κοινής Συμφωνίας¨ (Consensus Algorithms) , κατασκευάζουμε Αλγορίθμους χαμήλης πολυπλοκότητας, για την υλοποίηση ενός Kατανεμημένου Φίλτρου Kalman, θεωρώντας ότι όλοι οι κόμβοι είναι ομότιμοι (peer-to-peer αρχιτεκτονικές), κάθε κόμβος επικοινωνεί μόνο με τους γειτονικούς του και δεν υπάρχουν Fusion Centers. Παρουσιάζουμε έτσι τρεις διαφορετικούς επαναληπτικούς αλγορίθμους βασιζομένων σε δύο διαφορετικές λογικές και τέλος προσομοιώνουμε και αξιολογούμε την επίδοση καθενός από αυτούς. / In this thesis we deal with the development of techniques for implementing a distributed Kalman filter in a sensor network (WSN). Ιn recent years these networks have experienced rapid growth, due to the numerous applications in various fields of human activity. The problem we discuss here is the attempt to estimate the state of a stochastic process which is monitored by nodes-sensors. The nodes that constitute these networks usually have limited “sense” capabilities, which means that each node is unable to produce a good estimate of the state, using only its own measurements. Various techniques have been proposed to solve this kind of problems, such as the Central Kalman Filter or several decentralized approaches, which did have a high computational cost that renders them impractical, especially for networks with a high number of nodes. Thus, in the present work, , we construct low complexity algorithms for the implementation of a Distirbuted Kalman Filter, using as a tool the theory of Consensus Algorithms and assuming that all nodes are peers (peer-to-peer architectures), each node communicates only with its neighboring and no Fusion Centers exist. Τhus, we present three different iterative algorithms based on two different approaches and finally simulate and evaluate the performance of each of them.

Made available in DSpace on 2014-06-11T19:30:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-05-25Bitstream added on 2014-06-13T20:00:52Z : No. of bitstreams: 1 santosfilho_ta_dr_ilha.pdf: 2642177 bytes, checksum: a573f612bae5589d3dc6e27aac3c59c1 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os sistemas operacionais possuem um papel fundamental nos microcomputadores, realizando o interfaceamento entre os aplicativos e o hardware. Além dos microcomputadores, atualmente, os sistemas operacionais são empregados em ambiente a com arquitetura restrita, como os microcontroladores, denominando-os como sistemas operacionais embarcados. Algumas das aplicações para os sistemas operacionais co embarcados são voltadas para as redes de transdutores inteligentes, realizando o a gerenciamento e controle do sistema em que atua. Neste trabalho apresenta-se o desenvolvimento de um nó de rede denominado NCAP, utilizando o kit DE2 e o sistema o operacional embarcado μClinux para o monitoramento e controle dos TIMs com diferentes interfaces conforme a norma IEEE 1451. O NCAP desenvolvido possui como característica a conexão de diferentes TIMs com recursos de controle e monitoramento com distintas a interfaces de comunicação, com fio (RS-232) e sem fio (ZigBee). Para realização dos testes, foram desenvolvidos 4 TIMs com diferentes características, sendo: 2 STIMs (IEEE P1451.2) e 2 WTIMs (IEEE 1451.5). Os testes foram realizados utilizando uma interface de rede externa, a Ethernet, que, por meio do microcomputador, é possível acessar a página web em um servidor embarcado instalado no nó de rede NCAP. Com isso, é possível realizar o controle e o monitoramento dos transdutores conectados ao TIM independente da interface de comunicação sem fio ou com fio. Além do acesso aos transdutores, e o nó possui características que facilitam o gerenciamento, como: servidor de FTP e acesso remoto. O desenvolvimento do nó de rede embarcado, padronizado pela norma o IEEE 1451, possibilita maior flexibilidade de implantação em locais remotos e facilita a ampliação do sistema sem efetuar grandes modificações na rede. Uma característica importante... / The operating systems have a key role in microcomputers, performing interfacing between applications and the hardware. In addition to computers, currently embedded operating systems are employed in an environment with restricted architecture, such as microcontrollers, terming them as embedded operating systems. Some of the applications for embedded operating systems are geared for smart transducer networks, making the management and control system in which it operates. This work presents the development of a network node denominated NCAP using the DE2 kit and embedded operating system μClinux for monitoring and control of TIMs with different interfaces based on IEEE 1451. The NCAP has developed the characteristic connection of different TIMs with monitoring and control capabilities with different communication interfaces, wired (RS-232) and wireless (ZigBee). The testing, four TIMs were developed with different characteristics, as follows: 2 STIMs (IEEE P1451.2) and two WTIMs (IEEE 1451.5). The tests were performed using an external network interface, Ethernet, that through the PC, you can access the web page in an embedded server installed on the network node NCAP. This makes it possible to perform control and monitoring of transducers connected to the TIM interface regardless of wireless or wired. In addition to access to the transducers, the node has features that facilitate the management, such as FTP server and remote access. The development of embedded network node, standardized by IEEE 1451, allows for greater flexibility of deployment in remote locations and facilitates the expansion of the system without making major changes in the network. An important feature is the dynamic development in relation to the hardware implemented in FPGA with Nios II processor, it is... (Complete abstract click electronic access below)

Orientador: Eduardo Paciência Godoy / Banca: Diego Colon / Banca: Mariza Antunes de Lemos / Resumo: A tecnologia de comunicação wireless vem se tornando parte fundamental do cotidiano das indústrias de processos, onde o uso de transmissores wireless aplicados à monitoração e controle já é uma realidade. A arquitetura de Sistema de Controle via Rede Sem Fio (WNCS) possui vantagens em relação às arquiteturas tradicionais ponto-a-ponto e às arquiteturas de redes cabeadas devido à facilidade de instalação, configuração e manutenção. No entanto, a evolução desta tecnologia introduziu novos desafios para a implementação da malha de controle fechada por um instrumento wireless como as não linearidades, perda de pacote de dados e restrições da comunicação de dados nas redes sem fio. Outro fator crítico relacionado à implementação de WNCSs é a fonte de energia limitada destes transmissores, que possuem vida útil dependente da quantidade de acessos e dados transmitidos. Este trabalho apresenta o estudo e o desenvolvimento de um controlador preditivo multi-rate como alternativa para melhorar a eficiência energética em aplicações industriais de WNCSs. A estratégia proposta não necessita receber constantemente os valores reais das variáveis do processo transmitidos pelos transmissores wireless, pois o controlador preditivo baseado em modelo (MPC) se utiliza do submodelo interno das variáveis de processo para estimar os valores das variáveis quando estas não são transmitidas. Dessa forma, uma diminuição da frequência de transmissão de dados na rede sem fio pode ser obtida e, consequentem... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Wirelles communication technology has become a fundamental part of the every day life of process industries, where the use of wereless transmitters for monitoring and control is already a reality. The archiecture of Wireless Networked Control Systems (WNCSs) has advantages over point-to-point and wiered networks architectures due to the ease of installation, configuration and maintenance. However, the evolution of this technology has introduced new challenges to the implementation of the closed loop control with a wiereless instrument as nonlinearities, packet losses and data communication constraints in the wiereless networks. Another critical factor related to implementation of WNCSs is the energy source of these transmitters, which have limited lifetime dependent on the amount of access and data transmitted. This work presents the study and the development of a multi-rate predictive controller as an alternative to improve energy efficiency in industrial applications of WNCSs. The proposed strategy does not need to frequently receive process variables transmitted by wireless transmitters, because the model predictive controller (MPC) uses the internal submodel of the process variables to estimate the variables values when they are not transmitted. Thus, a decrease in the frequency of data transmission on the wireless network can be obtained and consequently a reduction of energy consumption of wereless devices. Simulation results for different operating conditions of a multivariable WNCS of coupled tanks shows that the multi-rate MPC provides robusstness and it is effective for WNCS applications, ensuring control and stability requirements even with the reduction of the transmission frequency of the feddback data in the wiereless network. In addition, energy consumption results from the WNCS devices showed that MPC multi-rate provides 20% of energy... (Complete abstract click electronic access below) / Mestre

abstract: Distributed inference has applications in fields as varied as source localization, evaluation of network quality, and remote monitoring of wildlife habitats. In this dissertation, distributed inference algorithms over multiple-access channels are considered. The performance of these algorithms and the effects of wireless communication channels on the performance are studied. In a first class of problems, distributed inference over fading Gaussian multiple-access channels with amplify-and-forward is considered. Sensors observe a phenomenon and transmit their observations using the amplify-and-forward scheme to a fusion center (FC). Distributed estimation is considered with a single antenna at the FC, where the performance is evaluated using the asymptotic variance of the estimator. The loss in performance due to varying assumptions on the limited amounts of channel information at the sensors is quantified. With multiple antennas at the FC, a distributed detection problem is also considered, where the error exponent is used to evaluate performance. It is shown that for zero-mean channels between the sensors and the FC when there is no channel information at the sensors, arbitrarily large gains in the error exponent can be obtained with sufficient increase in the number of antennas at the FC. In stark contrast, when there is channel information at the sensors, the gain in error exponent due to having multiple antennas at the FC is shown to be no more than a factor of 8/π for Rayleigh fading channels between the sensors and the FC, independent of the number of antennas at the FC, or correlation among noise samples across sensors. In a second class of problems, sensor observations are transmitted to the FC using constant-modulus phase modulation over Gaussian multiple-access-channels. The phase modulation scheme allows for constant transmit power and estimation of moments other than the mean with a single transmission from the sensors. Estimators are developed for the mean, variance and signal-to-noise ratio (SNR) of the sensor observations. The performance of these estimators is studied for different distributions of the observations. It is proved that the estimator of the mean is asymptotically efficient if and only if the distribution of the sensor observations is Gaussian. / Dissertation/Thesis / Ph.D. Electrical Engineering 2010

L'utilisation des réseaux de capteurs sans fil (WSN) ne cesse d'augmenter au point de couvrir divers domaines et applications. Cette tendance est supportée par les avancements techniques achevés dans la conception des capteurs, qui ont permis de réduire le coût ainsi que la taille de ces composants. Toutefois, il reste plusieurs défis qui font face au déploiement et au bon fonctionnement de ce type de réseaux et qui parviennent principalement de la limitation des ressources de capteurs ainsi de l'imperfection des données collectées. Dans cette thèse, on adresse le problème de collecte de données et de détection d'anomalies dans les réseaux de capteurs. Nous visons à assurer ces deux fonctionnalités tout en économisant l'utilisation des ressources de capteurs et en prolongeant la durée de vie de réseaux. Tout au long de ce travail, nous présentons plusieurs solutions qui permettent une collecte efficace de données de capteurs ainsi que une bonne détection des éventuelles anomalies. Dans notre première contribution, nous décrivons une solution basée sur la technique Compressive Sensing (CS) qui permet d'équilibrer le trafic transmis par les nœuds dans le réseau. Notre approche diffère des solutions existantes par la prise en compte de la corrélation temporelle ainsi que spatiale dans le processus de décompression des données. De plus, nous proposons une nouvelle formulation pour détecter les anomalies. Les simulations réalisées sur des données réelles prouvent l'efficacité de notre approche en termes de reconstruction de données et de détection d'anomalies par rapport aux approches existantes. Pour mieux optimiser l'utilisation des ressources de WSNs, nous proposons dans une deuxième contribution une solution de collecte de données et de détection d'anomalies basée sur la technique Matrix Completion (MC) qui consiste à transmettre un sous ensemble aléatoire de données de capteurs. Nous développons un algorithme qui estime les mesures manquantes en se basant sur plusieurs propriétés des données. L'algorithme développé permet également de dissimuler les anomalies de la structure normale des données. Cette solution est améliorée davantage dans notre troisième contribution, où nous proposons une formulation différente du problème de collecte de données et de détection d'anomalies. Nous reformulons les connaissances a priori sur les données cibles par des contraintes convexes. Ainsi, les paramètres impliqués dans l'algorithme développé sont liés a certaines propriétés physiques du phénomène observé et sont faciles à ajuster. Nos deux approches montrent de bonnes performances en les simulant sur des données réelles. Enfin, nous proposons dans la dernière contribution une nouvelle technique de collecte de données qui consiste à envoyer que les positions les plus importantes dans la représentation parcimonieuse des données uniquement. Nous considérons dans cette approche le bruit qui peut s'additionner aux données reçues par le nœud collecteur. Cette solution permet aussi de détecter les pics dans les mesures prélevées. En outre, nous validons l'efficacité de notre solution par une analyse théorique corroborée par des simulations sur des données réelles / The use of Wireless Sensor Networks (WSN)s is steadily increasing to cover various applications and domains. This trend is supported by the technical advancements in sensor manufacturing process which allow a considerable reduction in the cost and size of these components. However, there are several challenges facing the deployment and the good functioning of this type of networks. Indeed, WSN's applications have to deal with the limited energy, memory and processing capacities of sensor nodes as well as the imperfection of the probed data. This dissertation addresses the problem of collecting data and detecting anomalies in WSNs. The aforementioned functionality needs to be achieved while ensuring a reliable data quality at the collector node, a good anomaly detection accuracy, a low false alarm rate as well as an efficient energy consumption solution. Throughout this work, we provide different solutions that allow to meet these requirements. Foremost, we propose a Compressive Sensing (CS) based solution that allows to equilibrate the traffic carried by nodes regardless their distance from the sink. This solution promotes a larger lifespan of the WSN since it balances the energy consumption between sensor nodes. Our approach differs from existing CS-based solutions by taking into account the sparsity of sensory representation in the temporal domain in addition to the spatial dimension. Moreover, we propose a new formulation to detect aberrant readings. The simulations carried on real datasets prove the efficiency of our approach in terms of data recovering and anomaly detection compared to existing solutions. Aiming to further optimize the use of WSN resources, we propose in our second contribution a Matrix Completion (MC) based data gathering and anomaly detection solution where an arbitrary subset of nodes contributes at the data gathering process at each operating period. To fill the missing values, we mainly relay on the low rank structure of sensory data as well as the sparsity of readings in some transform domain. The developed algorithm also allows to dissemble anomalies from the normal data structure. This solution is enhanced in our third contribution where we propose a constrained formulation of the data gathering and anomalies detection problem. We reformulate the textit{a prior} knowledge about the target data as hard convex constraints. Thus, the involved parameters into the developed algorithm become easy to adjust since they are related to some physical properties of the treated data. Both MC based approaches are tested on real datasets and demonstrate good capabilities in terms of data reconstruction quality and anomaly detection performance. Finally, we propose in the last contribution a position based compressive data gathering scheme where nodes cooperate to compute and transmit only the relevant positions of their sensory sparse representation. This technique provide an efficient tool to deal with the noisy nature of WSN environment as well as detecting spikes in the sensory data. Furthermore, we validate the efficiency of our solution by a theoretical analysis and corroborate it by a simulation evaluation

.Wireless Sensor Networks importance is rapidly increasing and becoming a vital element in the process of gathering information in almost every scientific and practical aspect, but since the sensor node is usually a small device and has a battery with very limited life, power consumption is turning out to be the main drawback of this significant technology thus a lot of work and researches is going on to find new ways to reduce the power needed to operate those sensors. One of the main power consuming functionality of this technology is the wireless transmission of the data that the sensors collect across the fields [5][6]. In order to overcome this restriction, many proposals have been made to create an optimal algorithm that can guide the way each sensor node transmit it's data in order to reduce the power needed for the transmission process. This research focuses on creating a simplified scheduling algorithm that can break up the transmission waves into chains of nodes, so that each node transmits the data that has been collected to the best available node around, and so on till the information is propagated to the main server that collects all the information and analyze them.This newly proposed algorithm takes many attributes into considerations, but the main ones are the geographical information and the load that each senor node carries. A simulation model has been created to verify the effectiveness of the algorithm and to compare how close the results to the ideal network configuration are.

L'essor rencontré par les différentes technologies dédiées aux réseaux de capteurs (WSN), a conduit au développement de plateformes capables d'opérer dans deux technologies différentes, adaptatives aux contextes de transmission. De telles plateformes ouvrent la porte à la conception de réseaux multitechnologies, que nous proposons d'exploiter dans le but de réduire la consommation d'énergie globale. Dans le but d'exploiter ces réseaux multitechnologies, nous décrivons les principales technologies de l'Internet des Objets (IoT), en les comparant sur un pied d'égalité grâce à l'analyseur que nous avons développé, puis les classifions en fonction des mécanismes MAC qu'elles exploitent. Nous analysons ensuite le lien entre le contexte applicatif (latence et fréquence de la génération de données) et le mécanisme MAC consommant le moins d'énergie pour ce contexte applicatif.Nous remarquons alors que les technologies exploitants un mécanisme MAC synchrone sont les plus adaptées aux trafics applicatifs périodiques dont les intervalles entre les générations de données sont courts. En effet, pour ces trafics, la dérive d'horloge entraine un coût de maintien de la synchronisation active trop élevé dans le cas de trafics périodiques rares. De plus, nous remarquons que la gestion des trafics applicatifs rares contraints en latence repose, dans les solutions existantes, sur l'utilisation d'une plateforme constamment active en mode de réception. Nous proposons alors d'exploiter les plateformes multitechnologies pour constituer un réseau synchrone dans lequel chaque nœud répartit son activité dans le temps pour globalement économiser de l'énergie pour remplacer le rôle du dispositif constamment disponible utilisé pour acheminer des trafics asynchrones contraints en latence. Nous remarquons que lors de la procédure d'attache au réseau synchrone, la situation du nœud qui tente de rejoindre un réseau synchrone dans le but d'y acheminer des données est similaire à la situation d'un nœud asynchrone qui souhaite acheminer des données au sein d'un réseau synchrone.Ainsi, nous proposons d'exploiter la phase d'attache au réseau pour acheminer des trafics émanants de noeuds asynchrones, contraints en latence, au sein d'un réseau synchrone.Cependant, les procédures actuellement standardisées d'attache au réseau sont naïves et très coûteuse en énergie, ce qui décourage l'utilisation d'un mode de communication asynchrone, reposant sur une succession d'associations/désassociations du réseau : nous proposons deux approches pour réduire le coût de cette procédure d'attache à un réseau TSCH. La première repose sur l'exploitation de séquences mathématiques dont la propriété est d'étaler les périodes d'activités dans le temps, tout en minimisant l'impact sur la latence de la procédure, pour diminuer le coût énergétique global de la procédure d'attache. La deuxième méthode proposée exploite les trames d'acquittement (ACK) des communications TSCH pour y ajouter des éléments d'informations : la date d'envoi de la prochaine trame de synchronisation sur le même canal physique que celui utilisé pour l'envoi de la trame d'ACK. Grâce au développement d'un simulateur des performances de la phase d'attache à un réseau TSCH, nous montrons que les protocole d'attaches proposés obtiennent de meilleures performances, soit en termes de latence, soit en termes de consommation d'énergie globale, que les protocoles d'attache classiquement utilisés dans les réseaux de capteurs.Enfin, nous proposons d'exploiter les mécanismes de la deuxième proposition d'attache au réseau pour l'envoi de trames de sollicitation à destination d'un nœud fonctionnant avec une technologie asynchrone, permettant ainsi d'acheminer un trafic asynchrone au sein d'un réseau synchrone en une latence bornée. Nous montrons la faisabilité et prouvons l'intérêt d'une telle proposition. / The growth of various technologies dedicated to sensor networks (WSN) has led to the development of platforms capable of operating in two different technologies, adaptive to transmission contexts. Such platforms open the door to the design of multi-technology networks, which we propose to exploit to reduce overall energy consumption. In order to exploit these multi-technology networks, we describe the main Internet of Things (IoT) technologies, comparing them on an equal footing thanks to the analyzer we developed, and classify them according to the MAC mechanisms they use. We then analyze the link between the application context (latency and frequency of data generation) and the MAC mechanism that consumes the least energy for this application context.We note that the technologies operating with a synchronous MAC mechanism are the most suitable for periodic application traffic with short intervals between data generation. For these traffic patterns, clock drift leads to extensive traffic overhead because of the need to actively maintain synchronization for sparse periodic traffic.Moreover, we notice that, in the existing solutions, the management of sparce application traffic management is based on the use of an always-on platform (in reception mode). We thus propose to exploit the multi-technology platforms to build a synchronous network in which each node distributes its activity over time to globally save energy by replacing the role of the always-on platform, while guaranteeing the delivery of the latency-constrained asynchronous traffic.We notice that during the synchronous network joining phase, the situation of the node attempting to join a synchronous network is similar to the situation of an asynchronous node wanting to deliver data through a synchronous network.Thus, we propose to exploit the synchronous network joining phase to route latency-constrained traffic originating from asynchronous nodes through the synchronous network.However, the currently standardised network attachment procedures are naïve and energy-greedy, which discourages the use of an asynchronous communication mode, based on a succession of network associations/dissociations: we thus propose two approaches to reduce the cost of the TSCH network attachment procedure.The first is based on the use of mathematical sequences wich distribute the periods of activity over time, while minimizing the impact on the latency of the procedure, in order to reduce the overall energy cost of the attachment procedure. The second proposed method exploits the acknowledgement frames (ACK) of TSCH data communications to embed the date of the next synchronization frame transmission on the same physical channel as the ACK frame. Thanks to the development of a simulator of the TSCH joining phase, we show that the proposed protocols achieve better performance, either in terms of joining latency, or in terms of overall energy consumption, than the standard joining protocols used in WSN.Finally, we propose to exploit the mechanisms of the second proposal for sending request frames to a node operating with an asynchronous technology, thus enabling asynchronous traffic to be routed through a synchronous network in bounded latency. We demonstrate the value and feasibility of such a proposal.

Energy conservation is a main concern in Wireless Sensor Networks (WSN). To reduce energy consumption it is important to know how it is spent and how much is available during the node and network operation. Several previous works have proposed energy consumption models focused on the communication module, while neglecting the processing and sensing activities. Other works presented more complex and complete models, but lacked experiments to demonstrate their accuracy in real deployments. The main objective of this work is to design and to evaluate an accurate energy consumption model for WSN, which considers the sensing, processing, and communication modules usage. This model was used to implement two energy consumption prediction mechanism. One mechanism is based in Markov chains and the other one is based in time series analysis. The metrics to evaluate the model and prediction mechanisms performance were: energy consumption estimation accuracy, energy consumption prediction accuracy, and node\'s communication and processing resources usage. The energy consumption prediction mechanisms performance was compared using two implementation schemes: running the prediction algorithm in the sensor node and running the prediction algorithm in a Software-Defined Networking controller. The implementation was conducted using IT-SDN, a Software-Defined Wireless Sensor Network framework. For the evaluation, simulation and emulation used COOJA, while testbed experiments used TelosB devices. Results showed that considering the sensing, processing, and communication energy consumption into the model, it is possible to obtain an accurate energy consumption estimation for Wireless Sensor Networks. Also, the use of a Software-Defined Networking controller for processing complex prediction algorithms can improve the prediction accuracy. / A conservação da energia é uma das principais preocupações nas Redes de Sensores Sem Fio (WSN, do inglês Wireless Sensor Networks). Para reduzir o consumo de energia, é importante saber como a energia é gasta e quanta energia há disponível durante o funcionamento da rede. Diversos trabalhos anteriores propuseram modelos de consumo de energia focados no módulo de comunicação, ignorando o consumo por tarefas de processamento e sensoriamento. Outros trabalhos apresentam modelos mais completos e complexos, mas carecem de experimentos que demonstrem a exatidão em dispositivos reais. O objetivo principal deste trabalho é projetar e avaliar um modelo de consumo de energia para WSN que considere o consumo por sensoriamento, processamento e comunicação. Este modelo foi utilizado para implementar dois mecanismos de previsão de consumo de energia, um deles baseado em cadeias de Markov e o outro baseado em séries temporais. As métricas para avaliar o desempenho do modelo e dos mecanismos de previsão de consumo de energia foram: exatidão da estimativa de consumo de energia, exatidão da previsão de consumo de energia e uso dos recursos de comunicação e processamento do nó. O desempenho dos mecanismos de previsão de consumo de energia foram comparados utilizando dois esquemas de implementação: rodando o algoritmo de previsão no nó sensor e rodando o algoritmo de previsão em um controlador de rede definida por software. A implementação foi conduzida utilizando IT-SDN, um arcabouço de desenvolvimento de redes de sensores sem fio definidas por software. A avaliação foi feita com simulações e emulações utilizando o simulador COOJA e ensaios com dispositivos reais utilizando o TelosB. Os resultados mostraram que considerando o consumo de energia por sensoriamento, processamento e communicação, é possivel fazer uma estimativa de consumo de energia em redes de sensores sem fio com uma boa exatidão. Ainda, o uso de um controlador de rede definida por software para processamento de algoritmos de previsão complexos pode aumentar a exatidão da previsão.

Les réseaux de capteurs sans fil sont composés de petits équipements embarqués et autonomes qui coopèrent pour surveiller leur environnement de manière non-intrusive. Les données collectées par chaque capteur (tels que la température, des mouvements, des sons, etc.) sont remontées de proche en proche vers un puits de collecte en utilisant des technologies de communication sans fil. De plus en plus d'applications requièrent le placement des capteurs sur des éléments mobiles. Hors, à l'instar des équipements des réseaux IP, les nœuds capteurs pourront traverser plusieurs réseaux durant leurs déplacements. Cette thèse s'intéresse à cette problématique et propose deux solutions pour gérer ces nœuds mobiles. Notre première contribution, le protocole Mobinet, utilise la sur-écoute liée au médium radio pour détecter le voisinage d'un nœud mobile et ainsi lui permettre de gérer sa mobilité. D’autre part, l'intégration de nombreux nœuds mobiles dans les réseaux visités va augmenter le nombre de paquets transitant au sein de ces réseaux. Notre seconde proposition, le protocole CLOMAC, a pour objectif de réduire les congestions pouvant survenir en créant dynamiquement des chemins alternatifs vers le puits. / Wireless sensor networks are composed of small autonomous embedded devices which cooperate to monitor their environment in a less intrusive fashion. Data collected by each sensor node (such as temperature, movements, sounds, etc.) are reported to a sink station hop-by-hop using wireless transmissions. More and more application require sensors to be placed on mobile elements. However, in the manner of IP devices, mobile nodes may cross differents networks during their trips. This thesis focuses on this problematic and propose solutions to manage thoses mobile nodes. Our first contribution, the Mobinet protocol, uses the overhearing of the wireless medium to detect nodes in the vicinity of a mobile node and use this information to manage its mobility. Besides, integrating numerous mobile nodes will increase data trafic the visited networks. Our second proposition, the CLOMAC protocol, aims to reduces congestions which may appear by creating dynamic alternative path toward the sink station.

Com o crescimento e o desenvolvimento de aplicações para Redes de Sensores sem Fio (RSSF), os nós-sensores passaram a realizar o tratamento de eventos mais complexos, exigindo um maior desempenho de processamento e flexibilidade do hardware. Estas novas características visam atender os requisitos de diversas aplicações, assim como, apresentarem plataformas customizáveis que possuem somente os recursos necessários para atender estes requisitos. As RSSF, muitas vezes, necessitam de uma arquitetura flexível e que estejam aptas a adaptar-se a alterações de projeto ou do próprio ambiente em que se encontram inserido. A utilização de arquiteturas reconfiguráveis é uma solução que introduz esta flexibilidade e uma grande capacidade de processamento ao nó-sensor. Comparando com as arquiteturas ASICs (Application Specific Integrated Circuit), as arquiteturas reconfiguráveis apresentam um custo reduzido no desenvolvimento de aplicações, visto que a plataforma não fica fixa a somente uma aplicação. A reconfigurabilidade permite um ganho no custo e tempo de projeto, além de possibilitar o desenvolvimento de plataformas genéricas para atender um número maior de aplicações. A proposta destas plataformas é, não apenas oferecer uma plataforma eficiente e flexível, mas também potencializar a aplicação em sistemas mais complexos que necessitem de uma maior capacidade de processamento. Este trabalho apresenta o desenvolvimento de um nó-sensor reconfigurável e customizável para RSSF denominado FemtoNode. O FemtoNode possui em sua plataforma reconfigurável um processador especificado a partir de uma linguagem orientada a objetos Java e um módulo de comunicação sem fio para suportar comunicação entre os nós da rede. A arquitetura proposta foi validada com o estudo de caso de uma rede de sensores heterogênea composta por nós-sensores com plataformas distintas, sendo a análise realizada na presente dissertação. / With the growth and the development of new applications for Wireless Sensor Networks (WSN), sensors nodes are able to handle more complex events that require higher processing performance and hardware flexibility. These new features are intended to meet the requirements of various applications, as well to provide customized platforms that have only the resources needed to meet these requirements. WSNs often need a flexible architecture able to adapt to design and environment changes. The use of reconfigurable architectures is an alternative to bring more flexibility and more processing capability for the sensor-node. Compared with ASICs (Application Specific Integrated Circuit) architectures, which have a high cost in production setup, reconfigurable architectures enable a reduction in these costs because its architecture is not fixed to a single application. Reconfigurability allows a gain in the project costs and time development, and it enables the development of generic platforms to deal with a greater number of applications. Therefore, the proposal target architecture that aims to provide a flexible and efficient platform that require greater processing capacity which support the development of applications. In this work a reconfigurable and customizable sensor-node called FemtoNode is proposed. The FemtoNode has a reconfigurable platform and a wireless module to support applications for WSNs, using an object-oriented language Java as specification language of its architecture. The proposed concepts were validated with a case study of an heterogeneous wireless sensor composed of sensors nodes with different platforms, whose results are described in this work.