Wireless sensor networks are formed by mobile devices that collect and process data from an enviroment, and transmit them to a data center wich is responsible for taking decisions. This work aims to analyze the signal reconstruction in these networks using geostatistic techniques. Three processes of kriging are used: simple, ordinary and bayesian. Three approaches to simple krigingwere found in the literature, according to the way themean of the data is estimated,were assessed themall. A newBayesian approach is proposed: use general least square to estimate the mean, and set it as a constant into the Bayesian inference. The effect of clustering techniques is assessed, namely without clusters and with clusters formed by LEACH and SKATER algorithms. Bayesian kriging presents the best qualitative results in almost all scenarios, but it is not available to systems that require fast aswers; in this case we recommend ordinary kriging. The proposed variant of Bayesian kriging reduces the time required, without hampering the quality of the reconstructed signal, but the time reduction is not enough for real-time systems / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As Redes de Sensores sem Fios (RSsF) são conjuntos de dispositivos que obtêmamostras de fenômenos ambientais, sejam eles naturais (como, por exemplo, temperatura, pressão atmosférica, intensidade de iluminação, concentração de substâncias em cursos d água) ou antrópicos (qualidade do ar em sinais de trânsito, pressão ao longo de um oleoduto). Esses dispositivos têm despertadomuito interesse, tanto pelas suas potenciais aplicações quanto pelos desafios teóricos e tecnológicos que seu uso otimizado oferece. O objetivo deste trabalho trata da análise da reconstrução de sinais nessas redes, com base em técnicas de geoestatística. Analisam-se três processos de kriging: simples, ordinário e bayesiano. Ao simples, analisam-se três abordagens encontradas na literatura para estimação ou informação do parâmetro damédia e ao bayesiano propõe-se uma variante capaz de reduzir o tempo de processamento necessário, estimando a média por mínimos quadrados generalizados, sendo uma constante na inferência bayesiana. Leva-se em consideração o processo de agrupamento dos nós sensores, com simulações sem agrupamento e com os sensores agrupados pelos algoritmos LEACH e SKATER. O algoritmo de kriging bayesiano apresenta osmelhores resultados qualitativos namaioria dos casos,mas se torna inviável para sistemas que necessitemde respostas rápidas. Nesses casos, recomenda-se o algoritmo de kriging ordinário. A variante proposta para o kriging bayesiano reduz o tempo de computação, mas não o suficiente para sistemas de tempo real i

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

Orientador: Nelson Luis Saldanha da Fonseca / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-23T19:59:25Z (GMT). No. of bitstreams: 1 Andrade_TiagoPedrosodaCruzde_M.pdf: 5229881 bytes, checksum: 5a29eb81b4efd53a3cab70d6a8032bca (MD5) Previous issue date: 2013 / Resumo: O resumo poderá ser visualizado no texto completo da tese digital / Abstract: The complete abstract is available with the full electronic document. / Mestrado / Ciência da Computação / Mestre em Ciência da Computação

Orientador: Leandro Tiago Manera / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-26T15:58:55Z (GMT). No. of bitstreams: 1 DellaLucia_FelipeLorenzo_D.pdf: 3577549 bytes, checksum: 4c1aa6af60e58052accce7e28ad2c314 (MD5) Previous issue date: 2014 / Resumo: Este trabalho apresenta o desenvolvimento de um sistema sem fio de gestão de iluminação pública. Através do sistema desenvolvido, é possível controlar a potência de cada lâmpada de vapor de sódio de alta pressão dos postes de iluminação pública de determinada região. Desta maneira, nos horários em que as vias públicas se tornam menos utilizadas, é possível reduzir a potência e o brilho das lâmpadas e economizar energia elétrica. O sistema proposto utiliza o protocolo ZigBee para realizar a comunicação sem fio entre os módulos instalados nos postes. Este protocolo é baseado no protocolo IEEE 802.15.4 desenvolvido especialmente para redes de sensores sem fio e foca em baixo consumo de energia e transmissão da informação nó a nó da rede. Também é possível instalar sensores (luminosidade, umidade, etc.) nos módulos projetados e transformar cada unidade de iluminação pública em uma central de monitoramento de determinada região. Os resultados mostram que o sistema economiza energia, sendo possível reduzir a potência das lâmpadas em até 60% sem que o fator de potência do reator saia do valor mínimo estipulado na regulamentação (0,92). Os módulos desenvolvidos dão a opção ao operador de escolher a potência das lâmpadas em três valores distintos: 100%, 80% e 50% da potência nominal, sendo possível alterar estes valores conforme a necessidade do operador e do local onde o sistema será utilizado (condições de tráfego e segurança). O sistema foi testado em laboratório e em campo, em postes da Universidade Estadual de Campinas, onde ficou instalado pelo período entre 05/02/2014 e 01/04/2014. A potência das lâmpadas foi variada e medidas de iluminância e uniformidade foram realizadas na via. Foi possível concluir que o sistema é robusto, imune a interferências eletromagnéticas da rede de distribuição, e dá flexibilidade aos ajustes de iluminância e uniformidade de iluminação da via. O alcance de nó a nó da rede é, em média, de 260 m, o que torna a utilização do protocolo e do circuito desenvolvido adequados para esta aplicação, uma vez que a distância típica entre postes é de 30 a 40 metros. Estudos de viabilidade econômica foram realizados e mostram que o sistema é viável e apresenta taxas de retorno atrativas que dependem fortemente da tarifa de energia vigente / Abstract: This project presents the development of a wireless system for public street lighting management. Through the developed system, it is possible to control the power of each high pressure sodium lamp of the streetlights in a particular region. Thus, at times when the public streets become less utilized, it is possible to reduce the power and brightness of the lamps and save energy. The proposed system uses the ZigBee protocol to perform wireless communication between the modules installed on the lampposts. This protocol is based on IEEE 802.15.4 protocol, developed especially for wireless sensors networks and focus on low power consumption and data transmission node to node. It is also possible to install sensors (luminosity, humidity, etc.) in the designed modules and transform each unit of public lighting in a region into a monitoring station. The results show that the system saves energy and it is possible to reduce the lamp power by 64%, without reducing the ballast's power factor below the value stipulated in the regulation (0.92). The developed modules give the operator the option to choose the lamp power between three distinct values: 100%, 80% and 50% of rated nominal power, and it is also possible to change these values according to the operator's needs and the installment place characteristics (traffic usage, security). The system was tested in laboratory and on field, on the lampposts at State University of Campinas, where it remained installed in the period between February 5th and April 1st of 2014. The lamp power was varied and measurements of illuminance and uniformity were performed on the street. It was possible to conclude that the system is robust and immune to electromagnetic interference from the energy distribution grid, and gives flexibility for adjustments of brightness and uniformity of the street lighting. The reach node to node of the network is, on average 260 m, which makes the protocol and developed circuit adequate for this application, since the distance between lampposts is typically 30 to 40 meters. Economic viability studies have been conducted and show that the system is feasible and present attractive rates of return that depend heavily on the rate of current energy price / Doutorado / Eletrônica, Microeletrônica e Optoeletrônica / Doutor em Engenharia Elétrica

Soft materials have gained increasing prominence in science and technology over the last few decades. This shift from traditional rigid materials to soft, compliant materials have led to the emergence of a new class of devices which can interact with humans safely, as well as reduce the disparity in mechanical compliance at the interface of soft human tissue and rigid devices.<br><br>One of the largest application of soft materials has been in the field of flexible electronics, especially in wearable sensors. While wearable sensors for physical attributes such as strain, temperature, etc. have been popular, they lack applications and significance from a healthcare perspective. Point-of-care (POC) devices, on the other hand, provide exceptional healthcare value, bringing useful diagnostic tests to the bedside of the patient. POC devices, however, have been developed for only a limited number of health attributes. In this dissertation I propose and demonstrate wireless, wearable POC devices to measure and communicate the level of various analytes in and the properties of multiple biofluids: blood, urine, wound exudate, and sweat.<br><br>Along with sensors, another prominent area of soft materials application has been in actuators and robots which mimic biological systems not only in their action but also in their soft structure and actuation mechanisms. In this dissertation I develop design strategies to improve upon current soft robots by programming the storage of elastic strain energy. This strategy enables us to fabricate soft actuators capable of programmable and low energy consuming, yet high speed motion. Collectively, this dissertation demonstrates the use of soft compliant materials as the foundation for developing new sensors and actuators for human use and interaction.

The current state of wireless sensing technologies possesses a good reliability in terms of time response and sensing on movable parts or in embedded structures. Nevertheless, these tech- nologies involve energy supply such as battery and suffer from low resolution and bulky signal conditioning system for data processing. Thus, a RFID passive wireless sensor is a good candidate to overcome these issues. The feasibility of implementing microstrip patch antennas for sensing application were successfully investigated; however, low sensitivity was always a big issue to be concerned. Sensors based on nanocomposites attracted a lot of attention because of their excellent performance in term of light weight, high sensitivity, good stability and high resistance to corrosion but it lacks the capability of high conductivity, which limit their implication into RFID applications. This work introduces a novel high sensitive passive wireless strain and temperature sensors based on nanocomposites as sensing layer. To accomplish this, intrinsically conductive polymer based on carbon nanofillers nanocomposites are deeply studied and characterized. Then it’s performance is evaluated. Among them a novel tertiary nanocomposite is introduced, which opens the gate to new nanocomposite applications and thus broad- ens the application spectrum. Understanding the transport mechanism to improve the conductivity of the nanocomposite and extracting individually different models based on physical explanation of their piezoresistivity, and behavior under temperature and humidity have been developed. Afterwards, selected nanocomposites based on their high sensitivity to either strain or temperature are chosen to be used as sensing layer for patch antenna. The fabricated patch antenna has only one fundamental frequency, by determining the shift in its resonance frequency as function of the desired property to be measured; the wireless sensor characteristics are then examined. For strain sensing, the effect of strain is tested experimentally with the help of end-loaded beam measurement setup. For temperature sensing, the sensors are loaded in a controlled temperature/humid chamber and with the help of a vector network analyzer, the sensitivity of the antennas are extracted by acquiring the shift in the resonance frequency. The fabricated wireless sensors based on patch antenna are fabricated on very low lossy material to improve their gain and radiation pattern. This approach could be expanded also to include different type of substrates such as stretchable substrates i.e. elastomer polymer, very thing substrates such as Kapton, paper-based substrates or liquid crystal polymer.

Lors du développement d’un nouvel avion, la phase précédant l’obtention du certificat de navigabilité est basée sur de nombreux essais au sol ou en vol. Dans le domaine spatial, le lancement est l’une des phases les plus critiques pour les systèmes et des essais au sol particulièrement rigoureux sont donc réalisés afin de vérifier que la charge utile ne sera pas endommagéeDes milliers de capteurs de pression ou de jauges de contrainte sont ainsi utilisés par les industriels du secteur pour ce type d’essais. Mais tous ces éléments sont aujourd’hui connectés par des fils, ce qui engendre des contraintes de temps, de coût et de limitation du nombre de capteurs. Leur remplacement par des réseaux de capteurs sans fil est une solution évidente qui permet également d’augmenter le nombre de points de mesure. Cependant, il n’existe aujourd’hui aucun protocole permettant de répondre aux attentes et besoins des professionnels de l’aéronautique et du spatial. Les travaux présentés dans cette thèse ont ainsi vocation à répondre aux besoins d’un canal de communication très haut débit, basse consommation, à faible puissance d’émission, fiable et autorisant un grand nombre de nœuds. Un prototype de couche physique basée sur un système OFDM ultra large bande a été réalisé, testé et validé, et permet d’atteindre un débit de plus de 200 Mbits/s. / To evaluate a system's compliance with its specified requirements, Hardware System Testing is conducted on the complete and integrated system. This phase is essential in all industry branches, especially in the very regulated and critical aerospace world. In the final phase of the development of an airplane, flight test equipment gathers and analyzes data during flight to evaluate the flight characteristics of the aircraft and validate its design, including safety aspects. One of the most critical tests is the measure of the pressure around the wings during flight. All new aircrafts are computer designed with the use of virtual wind tunnels. So very accurate measures have to be done on the aircraft to validate the model before the aircraft can be industrially produced. In the case of satellites, vibration and mechanical stress are two critical phenomena a satellite endures during launch. This is leading to the necessity for accurate ground tests using strain gauges or thermal sensors before allowing a launch. All such systems used by aircraft and satellite manufacturers today are wired systems. Sensors put around the wings or inside the satellite compartments are wired to a concentrator inside the cabin or the operator’s room. Although good performances are observed in terms of measurement accuracy, these systems have strong drawbacks. The two most important ones are the weight and the cost of both the systems and their installation. An additional drawback concerning its use on aircrafts is due to the installation of a system that increases the weight of the aircraft and immobilizes it during many weeks due to the routing of every cable inside the wings. The cost and the complexity of such systems don’t allow a great number of measurement points. The replacement of conventional measurement networks by wireless sensor networks is not an obvious solution. Despite the great interest in wireless sensor networks in the recent years, the technological barriers are still very numerous and there is currently no protocol to meet the expectations and needs of aviation professionals. The work presented in this thesis aims to meet the needs of a high-speed, low power consumption, low emission and reliable communication layer. Measurements have been performed in real conditions using commercial devices based on the protocol MB-OFDM/Wimedia, the most common standard that approach the need expressed, and have served to define the basis of the study and have helped to select best development tracks. Measurements have demonstrated also the specificity of the propagation channel. In order to reduce the time between the choice of algorithms and their testing in real conditions, it became necessary to use a design flow called Specification - Exploration – Improvement based on automatic synthesis tools. This development cycle has identified specific material needs for the design of the demonstrator.The physical layer is based on an OFDM system and UWB to achieve a data rate of over 150 Mb/s. A fully functional demonstrator, implemented on FPGA and composed of four communicating nodes was presented and has been used to validate the physical layer. Finally first steps to develop a digital ASIC are presented to achieve the goal of low power consumption

Ces travaux portent sur la question de l’autonomie énergétiquedes capteurs sans fil dans un contexte aéronautique, à laquelle la récupérationet le stockage d’énergie ambiante sont susceptibles d’apporter uneréponse. Nous étudions dans un premier temps la génération thermoélectrique,destinée à être appliquée au suivi du vieillissement structurelprès de la zone moteur, et débouchant sur la réalisation d’un démonstrateur.Nous proposons ensuite une architecture de stockage capacitif qui,en s’adaptant à son état de charge, vise à améliorer la performance de cettesolution de stockage en termes de temps de démarrage, de taux d’utilisationd’énergie et sous certaines conditions, de transfert d’énergie. Finalement,nous rapportons les résultats d’une étude prospective sur la récupérationd’énergie du vent relatif grâce au phénomène aéroacoustique. Nousmontrons que cette méthode présente un potentiel énergétique intéressant,puis nous présentons la conception et la réalisation d’un circuit optimiséde gestion de l’énergie, permettant d’alimenter grâce à cette technique uncapteur sans fil de température / This work adresses the issue of energy autonomy within wirelesssensor networks embedded in aircrafts, which may be solved throughambient energy harvesting and storage. In a first study, we develop a demonstratorbased on thermal gradients energy harvesting, which is designedto supply power to a structural health monitoring system implementednear the engine zone. Thereafter, we introduce a capacitive storagearchitecture which self-adapts to its own state of charge, aiming at improvingits performance in terms of startup time, the energy utilization ratioand under some conditions, the energy transfer. Finally, we report the resultsof a prospective study on aeroacoustic energy harvesting appliedto the relative wind. It is shown that this method exhibits an interestingpotential in terms of generated power, then we introduce the design andthe realization of an optimized energy management circuit, allowing ourtechnique to supply power to a wireless temperature sensor

This research was born from NASA Kennedy Space Center’s (KSC) need for passive, wireless and individually distinguishable cryogenic liquid and H2 gas sensors in various facilities. The risks of catastrophic accidents, associated with the storage and use of cryogenic fluids may be minimized by constant monitoring. Accidents involving the release of H2 gas or LH2 were responsible for 81% of total accidents in the aerospace industry. These problems may be mitigated by the implementation of a passive (or low-power), wireless, gas detection system, which continuously monitors multiple nodes and reports temperature and H2 gas presence. Passive, wireless, cryogenic liquid level and hydrogen (H2) gas sensors were developed on a platform technology called Orthogonal Frequency Coded (OFC) surface acoustic wave (SAW) radio frequency identification (RFID) tag sensors. The OFC-SAW was shown to be mechanically resistant to failure due to thermal shock from repeated cycles between room to liquid nitrogen temperature. This suggests that these tags are ideal for integration into cryogenic Dewar environments for the purposes of cryogenic liquid level detection. Three OFC-SAW H2 gas sensors were simultaneously wirelessly interrogated while being exposed to various flow rates of H2 gas. Rapid H2 detection was achieved for flow rates as low as 1ccm of a 2% H2, 98% N2 mixture. A novel method and theory to extract the electrical and mechanical properties of a semiconducting and high conductivity thin-film using SAW amplitude and velocity dispersion measurements were also developed. The SAW device was shown to be a useful tool in analysis and characterization of ultrathin and thin films and physical phenomena such as gas adsorption and desorption mechanisms.