Wireless sensor networks (WSN) are event based systems that rely on the collective effort of densely deployed sensor nodes continuously observing a physical phenomenon. The spatio-temporal correlation between the sensor observations and the cross-layer design advantages are significant and unique to the design of WSN. Due to the high density in the network topology, sensor observations are highly correlated in the space domain. Furthermore, the nature of the energy-radiating physical phenomenon constitutes the temporal correlation between each consecutive observation of a sensor node. This unique characteristic of WSN can be exploited through a cross-layer design of communication functionalities to improve energy efficiency of the network. In this thesis, several key elements are investigated to capture and exploit the correlation in the WSN for the realization of advanced efficient communication protocols. A theoretical framework is developed to capture the spatial and temporal correlations in WSN and to enable the development of efficient communication protocols. Based on this framework, spatial Correlation-based Collaborative Medium Access Control (CC-MAC) protocol is described, which exploits the spatial correlation in the WSN in order to achieve efficient medium access. Furthermore, the cross-layer module (XLM), which melts common protocol layer functionalities into a cross-layer module for resource-constrained sensor nodes, is developed. The cross-layer analysis of error control in WSN is then presented to enable a comprehensive comparison of error control schemes for WSN. Finally, the cross-layer packet size optimization framework is described.

Made available in DSpace on 2016-12-12T17:38:35Z (GMT). No. of bitstreams: 1 Ana Teruko.pdf: 11607034 bytes, checksum: 72b3906b42ad639d1abd56a8054d9ffe (MD5) Previous issue date: 2008-05-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The wireless communication in the residential automation has became a very promising technology due to the easinesses in the installation, and for its flexibility, mobility and scalability. Inside this context, the objective of this work is to analyze and to implement two wireless communication standard protocols: Bluetooth and ZigBee. They are used to analyze theirs functionalities and applications under a domestic environment. Firstly, the Bluetooth protocol was used in order to verify its operation because this one is an already well known protocol. Secondly, the ZigBee protocol - IEEE 802.15.4 MAC was also tested due to its new protocol applied to small data communication and its low baud rate, star topozlogy and low energy consumption, which allows the control of householdelectric network. The project consisted of monitoring, controlling and configuring washing machines by using a wireless network through a remote virtual interface. The user interface of this system was done through a PDA (Personal Digital Assistant), which allowed to change the times of washing programs manual or automatic mode. The results indicated the feasibility of monitoring and controlling household-electric by implementing the IEEE 802.15.4 MAC Layer of ZigBee protocol. This implementing reached the main characteristics as described above. The maximum distance achieved in a star topology in the typical residence was 14 meters, without using routers. This distance can be increased implementing full ZigBee Protocol. Although the project was developed to washing machine, it also can be implemented to other household-electrics, such as: microwaves, heaters, air conditioners, refrigerators, etc. / A comunicação sem fio em automação residencial tem se tornado uma tecnologia muito promissora devido às facilidades na instalação, flexibilidade, mobilidade e escalabilidade. Dentro deste contexto, o objetivo deste trabalho é analisar e implementar dois padrões de comunicação sem fio: Bluetooth e ZigBee, a fim de analisar suas funcionalidades e aplicações em ambiente doméstico. O protocolo Bluetooth por se tratar de um protocolo já consagrado no mercado, foi utilizado no controle remoto de uma máquina lavadora, como proposta inicial deste trabalho. Depois, o protocolo ZigBee - IEEE 802.15.4 MAC foi implementado, pois este padrão é um protocolo novo aplicado a comunicação com pequenos pacotes de dados, baixa taxa de transmissão, topologia estrela e baixo consumo de energia, que são características importantes para controle de uma rede de eletrodomésticos. O projeto consistiu em desenvolver um protótipo de hardware e de software para monitorar, controlar e parametrizar máquinas lavadoras de roupas numa rede sem fio através de uma interface virtual remota. Esta interface do usuário com a rede foi feita através de um PDA (Personal Digital Assistant) que permitiu alterar os tempos de programação da máquina no modo manual ou automático. Os resultados mostraram a viabilidade de se construir uma rede de eletrodomésticos, implementando a camada de enlace IEEE 802.15.4MAC do protocolo de comunicação ZigBee. Esta implementação atingiu as principais características descritas acima. A distância máxima alcançada na topologia estrela numa residência típica foi de 14 metros, sem o uso de roteadores. Esta distância poderá ser aumentada através da implementação da camada de rede ZigBee. Embora o projeto tenha sido desenvolvido utilizando máquinas lavadoras, pode-se estendêlo a outros eletrodomésticos tais como: fornos de microondas, aquecedores, condicionadores de ar, refrigeradores, etc.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2009 / The purpose of this project is to develop methods for distribution network power quality' variations monitoring. Power quality (PO) has become a significant issue for both power suppliers and customers. There have been important changes in power system regarding to power quality requirements. "Power quality" is the combination at voltage quality and current quality. The main research problem of the project is to investigate the power quality of a distribution network by selection of proper measurement, applying and developing the existing classic and modern signal conditioning methods for power disturbance's parameters extracting and monitoring. The research objectives are: To study the standard lEC 61000-4-30 requirements. to investigate the common couplings in the distribution network. To identity the points for measurement, to develop MySQL database for the data from the measurement and to develop MATLAB software tor simulation of the network To develop methods based on Fourier transforms for estimation of the parameters of the disturbances. To develop software for the methods implementation, The influence of different loads on power quality disturbances are considered in the distribution network. Points on the network and meters according to the lEC power quality standards are investigated and applied for the CPUT Bellville campus distribution network. The implementation of the power quality monitoring for the CPUT Bellville campus helps the quality of power supply to be improved and the used power to be reduced. MATLAB programs to communicate with the database and calculate the disturbances and power quality parameters are developed.

[pt] O crescente interesse na utilização das redes de distribuição de energia elétrica como uma alternativa para o fornecimento de serviços de telecomunicações, tem motivado a pesquisa e o desenvolvimento de sistemas capazes de superar as características hostis deste ambiente como canal de comunicação. Com esta finalidade, este trabalho procura estimar o comportamento da rede PLC através da modelagem da função de transferência do canal, para a faixa de freqüência de 300 kHz a 30 MHz, por meio de um conjunto de parâmetros, os quais podem ser deduzidos da medição da resposta em freqüência. Dois modelos são apresentados para descrever a resposta em freqüência complexa de típicos canais power line, cobrindo todos os efeitos que os caracterizam, tais como o efeito de propagação por multipercursos causado pelas inúmeras reflexões nas junções da rede e o desvanecimento seletivo em freqüência. Os experimentos revelam que estes modelos apresentam todas as características principais da rede PLC podendo representar ferramentas úteis e efetivas na prática, oferecendo a possibilidade de realizar pesquisas para diferentes topologias de rede, a fim de estudar seu impacto no sistema de comunicação pela rede de energia elétrica. Além disso, propõem-se modelos de ajuste da função de transferência do canal a dados empíricos pelo método dos mínimos quadrados. / [en] The crescent interest on the utilization of the low voltage power distribution grid as an alternative to provide services of telecommunication has motivated the systems development able to surpass the hostile characteristics of this environment as a communication channel. Therefore, this work seek to estimate the behavior of PLC network (Power Line Communication) through the modelling of the channel transfer function, to the range of 300 kHz to 30 MHz, by means of a set of parameters, which can be derived from the measure of the frequency response. Two models are presented to describe the complex frequency response of power line channels, covering all effects that define them, for example, the multipaths propagation generated by uncountable reflections on the network connections and selective fading in the frequency. The results of experiments show that these models present the most important characteristics of PLC network, representing useful and effective tools in the practice, offering the possibility to do researches to different network topologies, in order to study the impact of these effects on the PLC system. Moreover, they`re proposed channel transfer function adjustment models through empiric data and the least square method.

Aujourd’hui les réseaux électriques sont exploités dans un marché dérégulé. Les gestionnaires des réseaux électriques sont tenus d’assurer un certain nombre de critères de fiabilité et de continuité du service, tout en minimisant le coût total consacré aux efforts effectués pour maintenir la fiabilité des installations. Il s’agit de trouver une stratégie, qui répond à plusieurs exigences, comme :le coût, les performances, la législation, les exigences du régulateur, etc. Cependant, le processus de prise de décision est subjectif, car chaque participant ramène sa contribution sur base de sa propre expérience. Bien que ce processus permette de trouver la « meilleure » stratégie, cette dernière n’est pas forcément la stratégie « optimale ». Ce compromis technico-économique a sensibilisé les gestionnaires des réseaux électriques à la nécessité d’un recours à des outils d’aide à la décision, qui doivent se baser sur des nouvelles approches quantitatives et une modélisation plus proches de la réalité physique.<p>Cette thèse rentre dans le cadre d’un projet de recherche lancé par ELIA, et dénommé COMPRIMa (Cost-Optimization Models for the Planning of the Renewal, Inspection, and Maintenance of Belgian power system facilities). Ce projet vise à développer une méthodologie qui permet de modéliser une partie du réseau électrique de transport (par les réseaux de Petri stochastiques) et de simuler son comportement dynamique sur un horizon donné (simulation de Monte Carlo). L’évaluation des indices de fiabilité permet de comparer les différents scénarios qui tentent d’améliorer les performances de l’installation. L’approche proposée est basée sur la stratégie RCM (Reliability-Centered Maintenance).<p>La méthodologie développée dans cette thèse permet une modélisation plus réaliste du réseau qui tient compte, entre autres, des aspects suivants :<p>- La corrélation quantitative entre le processus de maintenance et le processus de vieillissement des composants (par un modèle d’âge virtuel) ;<p>- Les dépendances liées à l’aspect multi-composant du système, qui tient compte des modes de défaillance spécifiques des systèmes de protection ;<p>- L’aspect économique lié à la stratégie de maintenance (inspection, entretien, réparation, remplacement), aux coupures (programmées et forcées) et aux événements à risque (refus disjoncteur, perte d’un client, perte d’un jeu de barres, perte d’une sous-station, etc.). / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished