Neste trabalho é apresentado um sistema de instrumentação inteligente integrado com a arquitetura Web Services e desenvolvido em conformidade com as diretrizes estabelecidas na norma IEEE 1451.1. O protocolo de transmissão de dados do sistema é associado ao conceito das especificações dos transdutores e a um Web Service que permita a configuração remota do sistema de aquisição de dados. Através de uma interface de supervisão remota, acessível via Internet a partir de qualquer navegador, o usuário é capaz de identificar quais são os sensores inteligentes que estão conectados em uma rede, através de uma identificação única associada às suas características (tipo, formatação dos dados, etc.). Nesta mesma interface de apresentação o usuário tem a liberdade de selecionar o número de sensores que deseja ativar para efetuar algum monitoramento. Após a seleção dos sensores é disponibilizada uma interface de monitoramento que permite a visualização dos dados através de um gráfico bem como permite ao usuário salvar em um arquivo texto os dados coletados. Na mesma interface de monitoramento é disponibilizado o Web Service que permite alterar o intervalo de coleta de dados. Um conjunto de computadores em uma rede local (Intranet) simula a rede de sensores inteligentes. Nesta mesma rede está conectado o servidor responsável pela disponibilização da interface de supervisão remota. / In this work is presented the integration of an established system of intelligent instrumentation with the Web Service?s architecture, in accordance with the IEEE 1451.1 standard. It is suggested the association of a data-communication protocol with the concept of Transducer Electronic Data Sheet (TEDS) to a Web Service for making possible the remote configuration of a data acquisition system. Through a remote supervisor interface, accessible via Internet from any browser, the user can, at the first moment, identify which are the smart sensors connected in a network, using an unique identification associated to its characteristics (type, data formatting, etc.). In the same graphical interface the user can choose which sensors wants to monitor and, after the selection, will have available the monitoring interface that enables data visualization through a graph and allows the user to save the collected data in a text file. In the same monitoring interface the Web Service is also available; it admits modifications on the data collection interval. A group of computers in a local network (Intranet) simulates the smart sensors network. In the same network is connected a server responsible for supplying the remote supervisor interface.

Dans le cadre des systèmes de transport intelligents (ITS), cette thèse concerne la conception d'une méthodologie de prédiction, en temps réel et pour différents horizons, du temps de parcours à partir des données de vitesse et de débit d'une route instrumentée. Pour atteindre cet objectif, deux approches sont considérées dans cette thèse. La première approche, dite « sans modèle », utilise exclusivement des mesures de vitesse. Grâce à l'utilisation astucieuse des données historiques, nous avons résolu le problème de prédiction comme étant un problème de filtrage. Pour ce faire, des données historiques sont utilisées pour construire des pseudo-observations qui alimentent un filtre de Kalman adaptatif (AKF). Sous une hypothèse de Gaussianité, les statistiques du bruit de processus sont estimées en temps-réel, tandis que les statistiques du pseudo-bruit d'observation sont déduites des données historiques adéquatement classées. La seconde approche, dite ‘'basée-modèle'', utilise principalement des mesures de débit et de vitesse. Contrairement à la précédente approche où la résolution spatiale est fixée par l'emplacement des capteurs, une discrétisation spatiale plus fine est considérée. Celle-ci s'avère possible grâce à l'utilisation du modèle CTM (Cell Transmission Model). Un observateur d'état commuté, de type Luenberger, permet d'estimer les états internes (densités des cellules). En utilisant uniquement les prédictions des débits des conditions frontières via une approche de type AKF similaire à celle développée dans la première approche, le modèle CTM contraint permet de prédire les densités des cellules et d'en déduire les vitesses et le temps de parcours. Les méthodes développées ont été validées expérimentalement en considérant la rocade sud grenobloise comme cas d'étude. Les résultats montrent que les deux méthodes présentent de bonnes performances de prédiction. Les méthodes proposées performent mieux que celles basées sur une utilisation directe des moyennes historiques. Pour l'ensemble des données considérées, l'étude a également montré que l'approche ‘'basée modèle‘' est plus adaptée pour des horizons de prédictions de moins de 30 min. / This dissertation falls within the domain of the Intelligent Transportation Systems (ITS). In particular, it is concerned with the design of a methodology for the real-time multi-step ahead travel time forecasting using flow and speed measurements from a instrumented freeway. To achieve this objective this thesis develops two main methodologies. The first one, a model-free, uses only speed measurements collected from the freeway, where a mean speed is assumed between two consecutive collection points. The travel time is forecasted using a noise Adaptive Kalman Filter (AKF) approach. The process noise statistics are computed using an online unbiased estimator, while the observations and their noise statistics are computed using the clustered historical traffic data. Forecasting problems are reformulated as filtering ones through the use of pseudo-observations built from historical data. The second one, a model-based, uses mainly traffic flow measurements. Its main appealing is the use of a mathematical model in order to reconstruct the internal state (density) in small road portions, and consequently exploits the relation between density and speed to forecast the travel time. The methodology uses only boundary conditions as inputs to a switched Luenberger state observer, based on the ``Cell Transmission Model'' (CTM), to estimate the road initial states. The boundary conditions are then forecasted using the AKF developed above. Consequently, the CTM model is run using the initial conditions and the forecasted boundaries in order to obtain the future evolution of densities, speeds, and finally travel time. The added innovation in this approach is the space discretization achieved: indeed, portions of the road, called ``cells'', can be chosen as small as desired and thus allow obtaining a finer tracking of speed variations. In order to validate experimentally the developed methodologies, this thesis uses as study case the Grenoble South Ring. This freeway, enclosing the southern part of the city from A41 to A480, consists of two carriageways with two lanes. For this study only the direction east-west was considered. With a length of about 10.5 km, this direction has 10 on-ramps, 7 off-ramps, and is monitored through the Grenoble Traffic Lab (GTL) that is able to provide reliable traffic data every 15 s, which makes it possible for the forecasting strategies to be validated in real-time. The results show that both methods present strong capabilities for travel time forecasting: considering the entire freeway, in 90% of the cases it was obtained a maximum forecasting error of 25% up to a forecasting horizon of 45 min. Furthermore, both methods perform as good as, or better than, the average historical. In particular, it is obtained that for horizons larger than 45 min, the forecasting depended exclusively on the historical data. For the dataset considered, the assessment study also showed that the model-based approach was more suitable for horizons shorter than 30 min.

Neste trabalho é apresentado um sistema de instrumentação inteligente integrado com a arquitetura Web Services e desenvolvido em conformidade com as diretrizes estabelecidas na norma IEEE 1451.1. O protocolo de transmissão de dados do sistema é associado ao conceito das especificações dos transdutores e a um Web Service que permita a configuração remota do sistema de aquisição de dados. Através de uma interface de supervisão remota, acessível via Internet a partir de qualquer navegador, o usuário é capaz de identificar quais são os sensores inteligentes que estão conectados em uma rede, através de uma identificação única associada às suas características (tipo, formatação dos dados, etc.). Nesta mesma interface de apresentação o usuário tem a liberdade de selecionar o número de sensores que deseja ativar para efetuar algum monitoramento. Após a seleção dos sensores é disponibilizada uma interface de monitoramento que permite a visualização dos dados através de um gráfico bem como permite ao usuário salvar em um arquivo texto os dados coletados. Na mesma interface de monitoramento é disponibilizado o Web Service que permite alterar o intervalo de coleta de dados. Um conjunto de computadores em uma rede local (Intranet) simula a rede de sensores inteligentes. Nesta mesma rede está conectado o servidor responsável pela disponibilização da interface de supervisão remota. / In this work is presented the integration of an established system of intelligent instrumentation with the Web Service?s architecture, in accordance with the IEEE 1451.1 standard. It is suggested the association of a data-communication protocol with the concept of Transducer Electronic Data Sheet (TEDS) to a Web Service for making possible the remote configuration of a data acquisition system. Through a remote supervisor interface, accessible via Internet from any browser, the user can, at the first moment, identify which are the smart sensors connected in a network, using an unique identification associated to its characteristics (type, data formatting, etc.). In the same graphical interface the user can choose which sensors wants to monitor and, after the selection, will have available the monitoring interface that enables data visualization through a graph and allows the user to save the collected data in a text file. In the same monitoring interface the Web Service is also available; it admits modifications on the data collection interval. A group of computers in a local network (Intranet) simulates the smart sensors network. In the same network is connected a server responsible for supplying the remote supervisor interface.

Les réseaux de capteurs sans-fil sont une nouvelle technologie qui permet de déployer des capteurs hétérogènes et de les faire communiquer sans fil et de façon autonome. Cette capacité nouvelle à surveiller ou instrumenter le monde qui nous entoure ouvre la voie à de nouvelles applications innovantes ou à une évolution majeure d’applications déjà existantes.D’une dizaine de nœuds à plusieurs milliers, les réseaux de capteurs sans fil commencent à conquérir le monde industriel et notre vie quotidienne. Leurs besoins en communications, gestion, génération et stockage de l’énergie, miniaturisation et réduction des coûts ne nécessitent pas seulement de perfectionner les technologies actuelles mais bien d’en inventer de nouvelles. Parmi toutes les applications révolutionnaires des réseaux de capteurs sans fil comme dans la santé, l’environnement, l’industrie et le militaire, l’une des applications les plus transformatrices est la surveillance de structure. La surveillance de structure est l’art de surveiller tout ce qui peut s’abimer, s’user ou tomber en panne. Elle est particulièrement importante dans les domaines des transports et du bâtiment, étant donné que la sécurité des personnes est en jeu. En plaçant aux endroits stratégiques des capteurs sans-fil, il sera possible de prévoir et de prévenir la défaillance d’un pont, l’usure d’un avion ou d’un train ou la déformation d’un bâtiment. La surveillance de structure permet de prévenir les pannes et les défaillances, de réduire les coûts de maintenance et d’améliorer les performances. C’est un processus complexe qui implique plusieurs technologies : des capteurs, la transmission de l’information et l’analyse des données. La nature (accéléromètre, gyroscope, jauge de contrainte, température, pression, fuite, givre, etc. . .), la position ainsi que le nombre de capteurs sont dictés et dépendants des besoins de l’analyse de la structure qui doit être effectuée. De ce fait, les contraintes imposées au système de transmission de données sans fil, afin d’offrir une couverture suffisante de la structure de l’appareil avec plusieurs centaines voire plusieurs milliers de capteurs que leur localisation rendra difficile d’accès, nécessitent des nouvelles innovations en matière d’efficacité énergétique et de performance de communication. Ce travail s’intéresse à la conception et l’implémentation d’un système de transmission de données dans un réseau de capteurs sans-fil. Après une présentation des exigences du système de surveillance de structure aéronautique, l’architecture générale du système de surveillance est décrite. Une couche physique spécifique à haute efficacité énergétique basée sur l’Impulse-Radio UltraWide Band a été conçue. Les designs complets de l’émetteur et du récepteur IR-UWB sont présentés ainsi que l'optimisation du codage canal par rapport à la consommation énergétique. Une couche MAC spécifique permettant un nombre important de nœuds et une efficacité énergétique élevée basée sur du TDMA reconfigurable a été conçue. Plusieurs prototypes ont été implémentés pour valider la conception et démontrer les performances. Ces implémentation utilise des techniques avancées d’optimisation de la consommation énergétique et de reconfigurabilité afin de répondre aux exigences des réseaux de capteurs sans-fil. Des simulations ASIC permettent également de prévoir que ce système permettra de supporter des débits applicatifs de plusieurs centaines de mégabits par seconde, tout en permettant à plusieurs dizaines de nœuds de communiquer. Les performances énergétiques de ce système de communication sont aujourd’hui à l’état de l’art. Enfin, cette technologie de communication sans-fil a été intégrée dans un système complet de deux nœuds capteurs et d’un routeur dans un démonstrateur FPGA / Wireless Sensor Networks (WSN) is an emerging technology which allows deploying wireless communicating autonomous heterogenous sensors. This monitoring capability paves the way for new innovative applications or breakthrough evolution of existing ones. WSN have started to change the industry and our daily lives. Their communication, energy, miniaturization and cost requirements cannot be met by evolutions of current technologies but will require new innovations.Among health, environment, industrial and military applications for WSN, one of the most revolutionary is Structural Health Monitoring (SHM). SHM is the art of monitoring anything which can wear, break down or be damaged. It is of utmost importance in safety sensitive domains such as the transport and construction industries.By placing sensors in carefully chosen locations, SHM will allow failure prediction, cost reduction and improved performance of bridges, planes, building or engines.The tens to thousands of sensors and the huge amount of data generated places a strong burden on the wireless communication of the nodes, which cannot be satisfied with today’s technology. This work presents the design and implementation works such a wireless communication system.Following a presentation of the context and requirement of this work, a general description of the SHM system is given. A specific highly energy efficient physical layer based on Impulse-Radio UltraWide Band (IR-UWB) has been designed.The complete IR-UWB transmitter and receiver are detailed, including the energy efficiency optimized channel coding. A specific Medium Access Control (MAC) layer allowing a large number of communicating nodes based on reconfigurableTime Division Multiple Access (TDMA) was designed. Several prototypes of this system have been implemented to prove feasibility and performance. These implementations employ advanced energy consumption reduction and reconfigurability techniques to answer WSN communication challenges. An ASIC implementation simulation has demonstrated hundreds of megabits per second data rate at state of the art energy efficiency

Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-09-05T21:53:30Z No. of bitstreams: 1 Tassalon_Dissertacao_Final.pdf: 3305292 bytes, checksum: d3d16f5296811c68fc2bd7790c8f62b9 (MD5) / Made available in DSpace on 2016-09-05T21:53:30Z (GMT). No. of bitstreams: 1 Tassalon_Dissertacao_Final.pdf: 3305292 bytes, checksum: d3d16f5296811c68fc2bd7790c8f62b9 (MD5) Previous issue date: 2015-12-18 / Funda??o de Amparo ? Pesquisa do Estado da Bahia - FAPEB / This work have proposed the adaptation and the development of algorithms for maximization of the redundant coverage of targets in wireless visual sensor networks. The most relevant concepts were described about the theory of visual sensors networks, development techniques of coverage algorithms and the details of the performed implementations. Besides, tests and comparisons were performed in simulation environments to demonstrate the obtained results, as well as to evaluate the performance of each developed algorithm of redundant coverage. / Esse trabalho prop?e a adapta ??o e o desenvolvimento de algoritmos para a maximiza ??o da cobertura visual redundante de alvos em redes de sensores visuais sem o. Assim, ser?o apresentados os conceitos mais importantes relacionados a teoria de redes de sensores visuais, as t ?cnicas de desenvolvimento de algoritmos de cobertura e os detalhes das implementa ??es realizadas. Al?m disso, testes e compara ??es foram realizados em ambiente de simula c?o para demonstrar os resultados obtidos, bem como avaliar o desempenho de cada um dos algoritmos de cobertura redundante desenvolvidos.

La thèse aborde le problème de la dissémination des informations liées au produit tout au long de son cycle de vie, par l’exploitation du concept de matière communicante. L’objectif général est de stocker dans la matière communicante ses caractéristiques initiales mais aussi l’évolution de ses propriétés durant son usage, en évitant de les perdre lors par exemple d’une transformation ou d’une destruction d’une partie du matériau. Dans le cadre de cette thèse, ce principe est appliqué dans le domaine des préfabriqués en béton, où des nœuds de réseaux de capteurs sans fil sont intégrés dans le béton. Ces nœuds sont alors utilisés pour stocker des informations relatives au cycle de vie du préfabriqué et à sa surveillance sur la phase d’usage. Un nouveau protocole de communication, nommé USEE, a été proposé et permet de diffuser uniformément les informations dans la matière en considérant qu’elles n’ont pas toutes la même importance. Le protocole USEE évite notamment la saturation rapide des mémoires des nœuds de façon à pouvoir stocker un maximum d’informations différentes. Ensuite, un protocole de lecture, intitulé RaWPG, a été développé. Il est adapté à la récupération d’informations uniformément réparties et consomme peu d’énergie. Ces deux protocoles ont été implémentés dans le simulateur réseau Castalia/OMNeT++ et ont permis de montrer leur intérêt par rapport au contexte applicatif mais aussi par rapport à d’autres protocoles similaires de la littérature / A new Internet of Things area is coming with communicating materials, which are able to provide diverse functionalities to users all along the product lifecycle. As example, it can track its own evolution which leads to gather helpful information. This new paradigm is fulfilled via the integration of specific electronic components into the product material. In this thesis, ultra-small wireless sensor nodes are used for concrete precast field. Indeed, storage of lifecycle information and data dissemination in communicating materials are very important issues. Therefore, this thesis provides a new protocol (USEE) for storing data by a systematic dissemination through the integrated sensor nodes. It guarantees that information could be retrieved in each piece of the concrete by intelligently managing data replication among each neighborhood of the sensor network. The protocol considers in the same set uniformity storage in the whole network, the data importance level, and the resource constraints of sensor nodes. Then, another new data retrieval protocol (RaWPG) is developed to extract the stored information. Castalia/OMNeT++ simulator is used to evaluate the performances of the proposed protocols

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-06-12T13:26:16Z No. of bitstreams: 1 GUSTAVO NÓBREGA MARTINS - DISSERTAÇÃO PPGCC 2016..pdf: 8931631 bytes, checksum: c124b37676d2bb06f4200b3eb548a6dd (MD5) / Made available in DSpace on 2018-06-12T13:26:16Z (GMT). No. of bitstreams: 1 GUSTAVO NÓBREGA MARTINS - DISSERTAÇÃO PPGCC 2016..pdf: 8931631 bytes, checksum: c124b37676d2bb06f4200b3eb548a6dd (MD5) Previous issue date: 2016-08-26 / Capes / As Redes de Sensores Sem Fio (RSSF) têm ganhado notoriedade em vários contextos de aplicações (e.g. aplicações militares, médicas e ambientais) em razão dos avanços obtidos no âmbito das tecnologias de sistemas eletromecânicos em escala micrométrica (Microscale Electro-Mechanical Systems - MEMS) e nanométrica (Nanoscale Electro-Mechanical Systems - NEMS). Esses progressos implicaram no desenvolvimento de nós sensores com menor custo, tamanho reduzido e com maior eficiência no consumo de energia. Mesmo diante dos avanços tecnológicos obtidos, os sensores sem fio ainda apresentam algumas restrições de processamento e memória, além do fornecimento de energia limitado devido ao uso de baterias como fonte de energia. Parte das pesquisas realizadas no âmbito das RSSF tem utilizado ferramentas de simulação para validar os achados de pesquisa devido ao menor custo e tempo exigidos por essa abordagem. Entretanto, algumas investigações apontaram que ferramentas de simulação em RSSF não contemplam fatores importantes que podem influenciar o desempenho das redes, como também questiona a confiabilidade dos resultados dessas ferramentas. Este trabalho de dissertação visou avaliar a confiabilidade do simulador de RSSF, Castália, com base em testbed no tocante a dois protocolos de comunicação: LEACH e Protocolo de Comunicação Direta. Resultados apontaram que o Castália, referente ao protocolo LEACH, superestimou o tempo de vida da rede com carga de tráfego estatisticamente equivalente. Em relação ao protocolo de Comunicação Direta, não houve equivalência de dados trafegados, bem como o tempo de vida também foi superestimado, além de não apresentar diferença nos resultados do tempo de vida entre os nós da rede, indicando um comportamento de descarga determinístico. Os achados deste trabalho demonstram que ferramentas de simulação trouxe significativos avanços no âmbito das RSSF, entretanto as saídas obtidas por meio dessas ferramentas ainda não podem representar com exatidão alguns cenários modelados em RSSF. / The Sensors Wireless Networks (WSN) have gained notoriety in various application contexts (e.g. military applications, medicai and environmental) due to the advances achieved in Microscale Electro Mechanical Systems - MEMS and Nanoscale Electro Mechanical Systems - NEMS. These growth resulted in sensors development with lower cost, reduced size and higher efficiency in energy consumption. Even with these technological advances, wireless sensors still have some constrains on processing and memory, in addition, the limited power source from batteries also is a challenge.

Le projet SACER vise à répondre aux demandes d’Airbus qui ont besoin de disposer de données décrivant le comportement d’un avion ou d’un satellite avant commercialisation ou lancement. Pour mieux répondre à cette demande, un réseau de capteurs sans fil remplacerait les équipements de test filaires existants. Le but est d’apporter des avantages tels qu’une réduction de poids, de coût et de connectique. Pour notre part, nous n’avons travaillé que sur l’application aéronautique.Pour alimenter les capteurs autonomes sans fil embarqués, dans le cadre de cette thèse, il faut concevoir une architecture de récupération d’énergie, un système de stockage de l’énergie ainsi que un circuit de gestion de ces énergies. La principale contrainte pour le système est qu’il doit pouvoir fonctionner de -50C à 100°C, tout en délivrant une puissance de sortie de 3 watts. De plus, l’épaisseur du système doit être inférieure à 3,2 mm.Pour notre travail, nous avons cherché, dans un premier temps, la meilleure solution possible sur le choix du type de cellules solaires. Le résultat sur les tests des cellules à différentes températures et irradiations dans les conditions de notre application est présenté. Dans un second temps, nous avons testé plusieurs types de systèmes de stockage d’énergie aux températures extrêmes. Enfin, la conception de l’architecture pour la gestion de l’énergie (vue d’ensemble des panneaux photovoltaïques, d’un circuit MPPT, des super condensateurs, et d’un régulateur) est présentée / Flight tests of a commercial aircraft consist in gathering data during flight to validate aircraft design. However they are very expensive for various reasons. One of them is that most of the sensors implemented to collect data are wired. As an example, for the sole system that monitors the vibrations onboard a large (more than 100 seats) aircraft, more than 100 sensors may be deployed. Such networks are complex to implement, mainly because of the required wiring. A wireless solution is therefore of great interest; however, such a cable-less implementation implies both wireless transmission of data together with energy autonomy.The purpose of this work is therefore to describe a design of a power generation system, focusing on photovoltaic, together with the associated management strategies for an autonomous wireless sensor network deployed for large aircraft in-flight tests. This work is a part of SACER project. The main requirements are related to the thickness of the system (less than 3,2mm in order not to disturb the aerodynamic air flow) and the output power (3 W per sensor node in order to power the sensor, data processing and transmission system). In addition, the system has to properly work at extremely high and low temperature (-50 to 100°C). Our system consists of three primary components to consider: Energy Harvesting system, Energy storage device and Energy management system.In this work, we firstly present the comparison of the performance of different photovoltaic technologies at different temperatures concerning their availability and achievable power density in aircraft applications. Secondly, we will investigate the possibility of using batteries and supercapacitor. Finally the power management system, composed by a photovoltaic panel, a power conditioning (MPPT function), supercapacitors and a DC/DC regulator, is presented

Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2016-02-05T15:54:58Z No. of bitstreams: 1 arquivototal.pdf: 4833402 bytes, checksum: 88ffcf3db8082fc50d986d744b72fd34 (MD5) / Made available in DSpace on 2016-02-05T15:54:58Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4833402 bytes, checksum: 88ffcf3db8082fc50d986d744b72fd34 (MD5) Previous issue date: 2013-02-25 / The use of Wireless Sensor Networks (WSN) has been widespread in many areas of research and application. The purpose of this work is a study on how to use sensors to monitor people on the move, having a WSN as a way in which the search will occur, but in order to predict the formation of groups in certain regions. For this work the network was designed and tested in the simulator Ptolemy II, using the ZigBee Communication protocol, where the sensors were positioned according to a Cartesian coordinate system. The WSN will detect people and identify common patterns of movement, such as speed, direction and type of movement, using parameters set in the simulator. People involved in the groups will be identified by RFID (Radio Frequency Identification) attached to his body. The movement of the crowd had its mathematical formalization based on parameters such as position of the group, number of people per group and duration of movement that define the characteristics necessary to simulate this scenario. From the formalization of the movement of the crowd, many data are collected at predetermined time intervals and interpreted by an algorithm, through the exchange of messages between sensors, estimates the crowd forming in the region defined as the target. In this work, were inserted charts and graphs that reflect the actual number of people moving towards the real target. These data are generated from the intense exchange of messages between sensors, obeying some parameters that favor established and the algorithm that estimates the crowd at the target formation at any given time. The accuracy of the prediction was measured by the amount of alarms issued that estimate and the formation of agglomerations of people in a given region. Thus, the identification of individuals by sensors is interpreted according to the possibility of formation of groups and their values disseminated by the network. The proposal is that this action will facilitate the process of decision making and thus help to characterize the formation of crowds. / O uso das Redes de Sensores sem Fio (RSSF) tem sido difundido em diversas áreas de pesquisa e aplicação. A proposta deste trabalho é um estudo sobre como utilizar sensores para monitorar pessoas em movimento, tendo uma RSSF como meio no qual a pesquisa deverá ocorrer, porém com o intuito de prever a formação de grupos em determinadas regiões. Para a realização deste trabalho a rede foi projetada e testada no simulador Ptolemy II, usando o protocolo ZigBee de comunicação, e os sensores foram posicionados de acordo com um sistema de coordenadas cartesianas. A RSSF deverá detectar as pessoas e identificar características comuns de movimento, como velocidade, direção e tipo de movimento, por meio de parâmetros configurados no simulador. As pessoas envolvidas nos grupos serão identificadas por etiquetas RFID (Radio Frequency Identification) presas ao seu corpo. O movimento de multidão teve sua formalização matemática baseada em parâmetros como posição do grupo, quantidade de pessoas por grupo e duração do movimento, que definem as características necessárias para a simulação desse cenário. A partir da formalização do movimento da multidão, vários dados foram coletados em intervalos de tempo previamente determinados e interpretados por um algoritmo que, por meio da troca de mensagens entre sensores, estima a formação de multidão na região definida como alvo. Neste trabalho, foram inseridos tabelas e gráficos que refletem o número real de pessoas que se deslocam em direção ao alvo real. Esses dados foram gerados a partir da intensa troca de mensagens entre os sensores, obedecendo alguns parâmetros estabelecidos e que favorecem o algoritmo que estima a formação de multidão no alvo, em determinado tempo. A acurácia da previsão foi medida pela quantidade de alarmes emitidos e que estimam a formação de aglomerações de pessoas em determinada região. Assim, a detecção de pessoas pelos sensores é interpretada de acordo com a possibilidade de formação de grupos, tendo seus valores disseminados pela rede. A proposta é que essa ação facilite o processo de tomada de decisão e, consequentemente, ajude na caracterização da formação de multidões

Les algorithmes distribués de consensus sont des algorithmes itératifs de faible complexité où les nœuds de capteurs voisins interagissent les uns avec les autres pour parvenir à un accord commun sans unité coordinatrice. Comme les nœuds dans un réseau de capteurs sans fil ont une puissance de calcul et une batterie limitées, ces algorithmes distribués doivent parvenir à un consensus en peu de temps et avec peu d’échange de messages. La première partie de cette thèse s’est basée sur l’étude et la comparaison des différents algorithmes de consensus en mode synchrone et asynchrone en termes de vitesse de convergence et taux de communications. La seconde partie de nos travaux concerne l’application de ces algorithmes de consensus au problème de la détection de trous de couverture dans les réseaux de capteurs sans fil.Ce problème de couverture fournit aussi le contexte de la suite de nos travaux. Il se décrit comme étant la façon dont une région d’intérêt est surveillée par des capteurs. Différentes approches géométriques ont été proposées mais elles sont limitées par la nécessité de connaitre exactement la position des capteurs ; or cette information peut ne pas être disponible si les dispositifs de localisation comme par exemple le GPS ne sont pas sur les capteurs. À partir de l’outil mathématique appelé topologie algébrique, nous avons développé un algorithme distribué de détection de trous de couverture qui recherche une fonction harmonique d’un réseau, c’est-à-dire annulant l’opérateur du Laplacien de dimension 1. Cette fonction harmonique est reliée au groupe d’homologie H1 qui recense les trous de couverture. Une fois une fonction harmonique obtenue, la détection des trous se réalise par une simple marche aléatoire dans le réseau. / Distributed consensus algorithms are iterative algorithms of low complexity where neighboring sensors interact with each other to reach an agreement without coordinating unit. As the nodes in a wireless sensor network have limited computing power and limited battery, these distributed algorithms must reach a consensus in a short time and with little message exchange. The first part of this thesis is based on the study and comparison of different consensus algorithms synchronously and asynchronously in terms of convergence speed and communication rates. The second part of our work concerns the application of these consensus algorithms to the problem of detecting coverage holes in wireless sensor networks.This coverage problem also provides the context for the continuation of our work. This problem is described as how a region of interest is monitored by sensors. Different geometrical approaches have been proposed but are limited by the need to know exactly the position of the sensors; but this information may not be available if the locating devices such as GPS are not on the sensors. From the mathematical tool called algebraic topology, we have developed a distributed algorithm of coverage hole detection searching a harmonic function of a network, that is to say canceling the operator of the 1-dimensional Laplacian. This harmonic function is connected to the homology group H1 which identifies the coverage holes. Once a harmonic function obtained, detection of the holes is realized by a simple random walk in the network.