<p>Wireless Sensor Network (WSN), a collection of “sensor nodes” promises to change the scientist’s approach of gathering the environmental data in various fields. Sensor nodes can be used for non-stop sensing, event detection, location sensing and local control of actuators, this concept gives surety to many latest application areas like agriculture, military, home or factory automation, logistics and so on. Remote surveillance and measurement missions can be performed by using WSNs. The hot research topic now-a-days is to make such networks remotely controllable and adaptive to the environment and mission.</p><p> </p><p>The work carried out in this thesis is the development of a surveillance application using TinyOS/nesC. The purpose of this application is to perform event-detection mission by using any one of the built-in sensor on Mica2 motes as well as a setup protocol is designed to make the WSN remotely controllable and adaptive to the mission. In this thesis, an experimental work is also performed using TinyDB to build up a surveillance system whose purpose is to detect and count the total number of person present at any time in a given room and to view the results at a remote place. Besides these two system applications, a comparative study between TinyDB and nesC is described which concludes that more hardware control can be achieved through nesC which is a more power efficient platform for long-term applications.</p>

Wireless Sensor Network (WSN), a collection of “sensor nodes” promises to change the scientist’s approach of gathering the environmental data in various fields. Sensor nodes can be used for non-stop sensing, event detection, location sensing and local control of actuators, this concept gives surety to many latest application areas like agriculture, military, home or factory automation, logistics and so on. Remote surveillance and measurement missions can be performed by using WSNs. The hot research topic now-a-days is to make such networks remotely controllable and adaptive to the environment and mission. The work carried out in this thesis is the development of a surveillance application using TinyOS/nesC. The purpose of this application is to perform event-detection mission by using any one of the built-in sensor on Mica2 motes as well as a setup protocol is designed to make the WSN remotely controllable and adaptive to the mission. In this thesis, an experimental work is also performed using TinyDB to build up a surveillance system whose purpose is to detect and count the total number of person present at any time in a given room and to view the results at a remote place. Besides these two system applications, a comparative study between TinyDB and nesC is described which concludes that more hardware control can be achieved through nesC which is a more power efficient platform for long-term applications.

Made available in DSpace on 2016-08-29T15:33:18Z (GMT). No. of bitstreams: 1 tese_5953_.pdf: 1630992 bytes, checksum: 8109a638255628096e2d5858d93042b3 (MD5) Previous issue date: 2012-08-31 / Assim como as redes de computadores convencionais, as Redes de Sensores Sem Fio (RSSF) estão sujeito aos mais diversos ataques, como negação de serviço, falsificação de endereços, comprometimento de nós, e outros ataques específicos para redes de sensores. Num cenário de emprego das RSSF em Cidades Inteligentes, a preocupação com a segurança toma uma dimensão ainda maior, considerando que dados críticos passarão a circular a todo o instante pela infra-estrutura de comunicação provida pelas redes. Neste sentido, a realização de pesquisas em segurança em RSSF se reveste de grande importância, e abre espaço para o desenvolvimento de trabalhos voltados para a criação de novos algoritmos, protocolos, ferramentas e ambientes específicos de Redes de Sensores sem Fio que contribuam para o aumento da segurança da rede. Este trabalho propõe um ambiente de experimentação para RSSF que permite simular redes mistas, interagir com as mesmas e avaliá-las no que diz respeito ao consumo de energia, topologia estabelecida, pacotes enviados/recebidos, etc. O ambiente desenvolvido é capaz de simular redes 6LoWPAN, sendo possível acessar os nós sensores através de seus respectivos endereços IPv6. A abordagem proposta permite que aplicações possam, remotamente, através da Internet, comunicar-se com a rede 6LoPAN, abstraindo-se do fato do ambiente ser completamente simulado. Como prova de conceito, foi simulada uma rede 6LoWPAN e, como método de avaliação de ataques, foi implementado um nó sybil, que foi injetado na topologia da rede, sendo posteriormente avaliada a organização topológica da rede com e sem o nó sybil em execução. Uma característica interessante da arquitetura proposta é que ela possibilita o teste remoto de aplicações; assim, uma máquina com maior capacidade de processamento pode ficar encarregada de gerar e simular a rede de sensores, enquanto as aplicações que coletam e tratam os dados são localizadas em outra máquina com menor capacidade de processamento. Como contribuição adicional o trabalho propõe uma metologia de associação à rede que baseada em chaves pré-compartilhadas. Essa metodologia visa mitigar ataques onde nós maléficos assumem diversas identidades na rede a fim de prejudicar a visão topológica da mesma. Além disto, é apresentado um mecanismo de proteção da chave pré-compartilhada através do processo de armazenamento somente em memória volátil, o que dificulta a descoberta da chave no caso do comprometimento de um nó, ou possibilita a destruição da chave junto com a morte do sensor ao término de sua energia.

Applications for Wireless Sensor Networks can be updated dynamically by means of wireless upgrade mechanisms. Current research efforts in wireless upgrade mechanisms for WSN have focused on transmitting application packets for upgrades via wireless medium. However, these schemes require significant overhead involved in sending and receiving application packets that affect the sensor operation, in addition to bringing the nodes down to reprogram and restart them. By designing applications in a way that allows dynamic functionality changes during operation, the overhead and sensor delays can be eliminated. Dynamically Controllable Application (DCA) is a novel scheme for designing WSN applications whose behavior can be rapidly and dynamically changed during operation. The results indicate that a veritable functionality change is achieved in a span of a few milliseconds.

No description available.

Les réseaux de capteurs sans fil (RCSFs) ont suscité un grand intérêt scientifique durant cette dernière décennie. Un des grands défis des RCSFs est d'assurer une communication avec la Qualité de Service (QoS) exigée par l'application tout en prenant en considération les contraintes intrinsèques des capteurs. Un autre défi est relatif à la génération des trafics hétérogènes avec des priorités diverses, ce qui impose des contraintes supplémentaires aux différents protocoles de communication. Dans cette thèse, nous nous intéressons aux protocoles de routage dédiés aux RCSFs. Dans un premier temps, nous proposons des améliorations de deux protocoles appartenant à deux catégories différentes de routage. L'objectif est de surmonter les contraintes liées aux caractéristiques des capteurs sans fil et d'assurer de meilleure performance. Dans un deuxième temps, nous proposons une solution pour remédier à la vulnérabilité de la technique des chemins multiples aussi bien dans le cas d'une seule source ou que dans le cas de plusieurs sources. Ainsi, nous avons proposé un protocole de routage à chemins multiples, capable de créer des chemins tout en évitant l'effet du rayon de détection de porteuse. Ce protocole nommé « Carrier Sense Aware Multipath Geographic Routing (CSA-MGR) », satisfait la QoS exigée par les RCSFs. Comme application directe de notre solution, nous avons étudié un scénario d'irrigation par goutte-à-goutte en utilisant les RCSFs. Principalement, nous nous sommes intéressés au cas d'un dysfonctionnement de système, tel que la rupture des tuyaux d'irrigation ou bien le blocage des émetteurs. Ainsi, nous distinguons deux niveaux de priorité pour les informations transmises par le réseau, et en utilisant le protocole CSA-MGR, nous concevons un routage selon la priorité exigée. Notre travail a été validé avec NS2 et TOSSIM ainsi par une implémentation réelle sur des noeuds capteurs TelosB. Les résultats des simulations numériques et des tests expérimentaux montrent l'apport de nos contributions par rapport aux solutions existantes. / Wireless Sensor Networks (WSNs) have aroused great scientific interest during the last decade. One of the greatest challenge of WSNs is to ensure communication with the Quality of Service (QoS) required by the application while taking into account the inherent constraints of the sensor nodes. Another challenge is related to the generation of heterogeneous traffic with different priorities, which imposes additional constraints on different communication protocols. In this thesis, we are interested specifically to routing protocols dedicated to WSNs. First, we propose improvements of protocols based on combinatorial optimization techniques and those based on nodes geographic positions to overcome the related constraints of WSNs. Secondly, we propose a solution to address the vulnerability of the multiple paths technique, whether for the case of a single source or several sources in the network. Thus, our main contribution is to provide a multi-path routing protocol, able to creating paths while avoiding the carrier sense range effect. This protocol denoted "Carrier Sense Aware Multipath Geographic Routing (CSA-MGR)" meets the QoS required by WSNs. As direct application of our solution, we studied a drip irrigation scenario using WSNs. Mainly, we studied the case where a system dysfunctioning occurs, such as irrigation pipe rupture or the emitters blocking. Also, we distinguish two priority levels for the data transmitted over the network, and based on the CSA-MGR, we design routing according to the required priority. Our work in this thesis has been validated through NS2 and TOSSIM simulators and also through a real implementation over the TelosB motes. The results of numerical simulations and experimental results show the advantage of our contributions compared to existing solutions.

Creating a secure wireless sensor network involves authenticating and encrypting messages that are sent throughout the network. The communicating nodes must agree on secret keys in order to be able to encrypt packets. Sensor networks do not have many resources and so, achieving such key agreements is a difficult matter. Many key agreement schemes like Diffie-Hellman and public-key based schemes are not suitable for wireless sensor networks. Pre-distribution of secret keys for all pairs of nodes is not viable due to the large amount of memory used when the network size is large. We propose a novel key management system that works with the random key pre-distribution scheme where deployment knowledge is unknown. We show that our system saves users from spending substantial resources when deploying networks. We also test the new system’s memory usage, and security issues. The system and its performance evaluation are presented in this thesis.

<p>In recent years, the development of wireless sensor networks has made a great progress. Early projects focused on replacement of existing systems equipped with wires. These systems started out as simple static data collection networks with one smart central node that could decide further actions based on the content of the collected data. Through time, the intelligence has become more decentralized, which means the nodes now can cooperate in a more efficient and dynamic manner. The task given is to evaluate TinyOS and NesC on specific hardware from Crossbow Technology Inc, applied on an application called the Open Secure Office Project. This application is designed to enhance the security without negative effects on comfort in a frequently visited open-plan office. Finally, a real world system demonstration should be performed. We propose a solution where there is no urgent need to cover the entire office area with radio signals to maintain a secure sensor system. This is true as long as all entries and exits to the office area are “guarded” by some base station which has as main task to keep track of people and equipment entering or leaving the office. Small scale tests have been performed which show that it is possible to easily develop and maintain a wireless sensor network security system, that could be coordinated by alternative systems.</p>

Localization of individual nodes in a wireless network is useful in many applications, e.g for tracking patients in hospitals. Using the Received Signal Strength Indicator, RSSI, for this purpose has been explored in numerous studies. It is energy efficient and rarely requires customised hardware of configuration. The possibility to use pre-configured, off-the-shelf products is especially important in large scale sensor network deployments. Using RSSI has, however, many drawbacks, since the radio signal is heavily affected by the surrounding envi- ronment. Most studies in this area discuss the impact of multipath effects. Our study on range based distance estimations, using the Telos hardware, shows that individual profiling requirements and antenna quality are equally challenging. Still, RSSI based indoor localization systems remains an active field of research. A multitude of approaches and algorithms have been proposed to gain accuracy in position estimations. The most common of these techniques are explored in this report. Based on previous work at The Polytechnic University of Catalonia, the Telos hardware has been integrated successfully with existing software to form local wireless sensor networks for indoor localization. We present applications developed on top of TinyOS, an operating system for embedded systems. These applications serve as a platform for related future work at The Polytechnic University of Catalonia and elsewhere.

Energy consumption and network latency are important issues in wireless sensor networks. The mechanism duty cycling is generally used in wireless sensor networks for avoiding energy consumption due to idle listening. Duty cycling, however, also introduces additional latency in communication among sensors. Some protocols have been proposed to work in wireless sensor networks with duty cycling, such as S-MAC and DW-MAC. Those protocols also tried to make efficient channel utilization and to mitigate the chance of packet collision and the network latency increase resulting from collision. DW-MAC was also designed to tolerate bursty and high traffic loads without increasing energy consumption, by spreading packet transmission and node wakeup times during a cycle. Some performance comparison between S-MAC and DW-MAC has been done in previous work; however, this comparison was performed in the ns-2 simulator only. In the real world, there are further issues not considered or discussed in the simulation, and some of those issues contribute significant influences to the MAC protocol performance. In this work, I implemented both S-MAC and DW-MAC physically on MICAz sensor motes and compared their performance through experiments. Through my implementation, experiments, and performance evaluation, hardware properties and issues that were not addressed in the previous work are presented, and their impacts on the performance are shown and discussed. I also simulated S-MAC and DW-MAC on ns-2 to give a mutual validation of the experimental results and my interpretation of the results. The experiences of physical implementations presented in this work can contribute new information and insights for helping in future MAC protocol design and implementation in wireless sensor networks.