M. Tech. Electrical Engineering. / Objectives of this research is to use the node orientation, coupled with antenna radiation pattern of each node, to improve the Received Signal Strength (RSS) range measurement technique. As energy eciency is critical to WSNs, it is necessary to minimize both computation and communication costs in any operation involving WSNs,including during the localisation process. To achieve that, accelerometer measurements are used to reduce the number of iteration of the optimisation process during the refinement phase by computing more accurately an initial position for the optimisation using dead reckoning and approach the localisation in a distributed manner. The contribution of this is the investigation and development of an ecient localisation algorithm that can be used on a low cost wireless sensor board developed using existing technology. A review of the existing methods is conducted to highlight the key aspect to consider when developing an ecient localisation algorithms. A mathematical modelling of the proposed algorithm is developed and simulation is conducted to analyse the performance of the algorithm. An exhaustive test bed hardware has been designed on which the algorithm can to be validated.

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Mobile wireless sensor networks are not widely implemented in the real world, even after years of research carried out in this field. One reason is the lack of understanding of the impact that mobility has on network performance. The simulation and emulation of mobile wireless sensor networks is necessary before they are deployed for the real-world applications. This thesis presents a simulation-based study of different mobility models. The total area coverage that depends on the pattern of node movements is observed through simulations. The spatial distribution of node locations is also studied. Various synthetic mobility models available are explored based on their theoretical descriptions. ‘BonnMotion' is used as the network simulator for investigating different mobility scenarios. The results obtained after simulations are imported to MATLAB and the analysis of node movements is done through various plots and inferences from the data. The comparison of mobility models is also discussed based on their spatial node distribution in the simulated scenarios.

In Wireless Sensor Actor Networks (WSANs), sensor nodes perform the sensing task and actor nodes take action based on the sensed phenomenon. The presence of actors in this configuration can not be benefited from, unless they are able to execute actions at right place and right time in the event region. The right place can be related to the accurate position of the sensor nodes. While, the right time is related to delivering the packets directly to the appropriate actors within the event specific response times. Hence, the efficient localization of sensor nodes, sensor-actor/actor-actor coordination and real-time routing is indispensable in WSANs. Furthermore, the limited energy levels and bandwidth of the state of art sensor nodes currently impose stringent requirements for low-complexity, low-energy, distributed coordination and cooperation protocols and their implementation. In this study, we propose an integrated framework which addresses the issues of sensors localization, network configuration, data aggregation, real-time data delivery, sensor-actor/actor-actor coordination and energy saving mechanisms. The proposal incorporates novel approaches on three fronts / (1) timing-based sensors localization (TSL) algorithm to localize the sensor nodes relative to actors, (2) real-time coordination and routing protocols and (3) energy conservation. The distributed real-time coordination and routing is implemented in addressing and greedy modes routing. A cluster-based real-time coordination and routing (RCR) protocol operates in addressing mode. The greedy mode routing approach (Routing by Adaptive Targeting, RAT) is a stateless shortest path routing. In dense deployment, it performs well in terms of delay and energy consumption as compared to RCR. To keep the traffic volume under control, the framework incorporates a novel real-time data aggregation (RDA) approach in RCR such that the packets deadlines are not affected. RDA is adaptive to the traffic conditions and provides fairness among the farther and nearer cluster-heads. Finally, framework incorporates a power management scheme that eliminates data redundancy by exploiting the spatial correlation of sensor nodes. Simulation results prove that the framework provides the real-time guarantees up to 95 % of the packets with lesser energy consumption of up to 33 % achieved using MEAC as compared to LEACH and SEP. The packet delivery ratio is also 60 % higher than that of semi-automated architecture. Furthermore the action accuracy is supported by TSL which restricts the localization errors less than 1 meter by tuning it according to the expected velocity of nodes and required accuracy.

M. Tech. Electrical Engineering. / Discusses node location as a major problem when considering several areas of application based on wireless sensor networks. Many localisation algorithms have been proposed in the literature to solve the problem of locating sensor nodes in WSN. However, most of these algorithms have poor localisation accuracy and high computational cost. Due to these limitations, this research study considers the modelling of an efficient and robust localisation scheme to determine the location of individual sensor nodes in WSN. To successfully solve this task, this research study focuses on the aspect of improving the position accuracy of wireless sensor nodes in WSN. The study considers a distance based cooperative localisation algorithm called Curvilinear Component Analysis Mapping (CCA-MAP) to accurately localise the sensor nodes in WSN. CCA-MAP is used because it delivers improved position accuracy and computational efficiency.

Rising from the “excess demand” modern societies and economies place on limited road resources, congestion causes increased vehicle emissions, decreases national efficiency, and wastes time (Downs, 2004). In order to minimise congestion’s impacts, traffic management systems gather traffic data and use it to implement efficient management algorithms (Downs, 2004). This dissertation’s purpose has been the development of a distributable vehicle presence detection sensor, which will wirelessly provide vehicle presence information in real time. To address the sensor’s wireless power requirements, the feasibility of self-powering the device via harvested energy has been investigated. Piezoelectric, electrostatic, and electromagnetic energy harvesting devices’ principles of operation and underlying theory has been investigated in detail and an overview presented alongside a literature review of previous vibration energy harvesting research. An electromagnetic energy harvesting device was designed, which consists of: a nylon reinforced rubber bladder, hydraulic piston, neodymium magnets, and wire-wound coil housing. Preliminary testing demonstrated a harvested energy between 100mJ and 205mJ per axle. This amount is able to be transferred to a 100O load when driven over at speeds between 10km/h and 50km/h. Combined with an embedded circuit, the energy harvester facilitated the development of a passive sensor, which is able to wirelessly transmit a vehicle’s presence signal to a host computer. The vehicle detected event is displayed via a graphical user interface. Energy harvesting’s ability to power the embedded circuit’s wireless transmission, demonstrated the feasibility of developing systems capable of harvesting energy from their environment and using it to power discrete electronic components. The ability to wirelessly transmit a vehicle’s presence facilitates the development of distributable traffic monitoring systems, allowing for remote traffic monitoring and management.

Les réseaux de capteurs sans fil émergent comme une technologie innovatrice qui peut révolutionner et améliorer notre façon de vivre, de travailler et d'interagir avec l'environnement physique qui nous entoure. Néanmoins, l'utilisation d'une telle technologie soulève de nouveaux défis concernant le développement de systèmes fiables et sécurisés. Ces réseaux de capteurs sans fil sont souvent caractérisés par un déploiement dense et à grande échelle dans des environnements limités en terme de ressources. Les contraintes imposées sont la limitation des capacités de traitement, de stockage et surtout d'énergie car ils sont généralement alimentés par des piles.Nous visons comme objectif principal à travers cette thèse à proposer des solutions permettant de garantir un certain niveau de fiabilité dans un RCSF dédié aux applications sensibles. Nous avons ainsi abordé trois axes, qui sont :- Le développement de méthodes permettant de détecter les noeuds capteurs défaillants dans un RCSF,- Le développement de méthodes permettant de détecter les anomalies dans les mesures collectées par les nœuds capteurs, et par la suite, les capteurs usés (fournissant de fausses mesures).- Le développement de méthodes permettant d'assurer l'intégrité et l'authenticité des données transmise dans un RCSF. / Wireless sensor networks emerge as an innovative technology that can revolutionize and improve our way to live, work and interact with the physical environment around us. Nevertheless, the use of such technology raises new challenges in the development of reliable and secure systems. These wireless sensor networks are often characterized by dense deployment on a large scale in resource-onstrained environments. The constraints imposed are the limitation of the processing, storage and especially energy capacities since they are generally powered by batteries.Our main objective is to propose solutions that guarantee a certain level of reliability in a WSN dedicated to sensitive applications. We have thus proposed three axes, which are:- The development of methods for detecting failed sensor nodes in a WSN.- The development of methods for detecting anomalies in measurements collected by sensor nodes, and subsequently fault sensors (providing false measurements).- The development of methods ensuring the integrity and authenticity of transmitted data over a WSN.

Philosophiae Doctor - PhD / Wireless sensor networks (WSNs) have become a popular research area that is widely gaining the attraction from both the research and the practitioner communities due to their wide area of applications. These applications include real-time sensing for audio delivery, imaging, video streaming, and remote monitoring with positive impact in many fields such as precision agriculture, ubiquitous healthcare, environment protection, smart cities and many other fields. While WSNs are aimed to constantly handle more intricate functions such as intelligent computation, automatic transmissions, and in-network processing, such capabilities are constrained by their limited processing capability and memory footprint as well as the need for the sensor batteries to be cautiously consumed in order to extend their lifetime. This thesis revisits the issue of the energy efficiency in sensor networks by proposing a novel clustering approach for routing the sensor readings in wireless sensor networks. The main contribution of this dissertation is to 1) propose corrective measures to the traditional energy model adopted in current sensor networks simulations that erroneously discount both the role played by each node, the sensor node capability and fabric and 2) apply these measures to a novel hierarchical routing architecture aiming at maximizing sensor networks lifetime. We propose three energy models for sensor network: a) a service-aware model that account for the specific role played by each node in a sensor network b) a sensor-aware model and c) load-balancing energy model that accounts for the sensor node fabric and its energy footprint. These three models are complemented by a load-balancing model structured to balance energy consumption on the network of cluster heads that forms the backbone for any cluster-based hierarchical sensor network. We present two novel approaches for clustering the nodes of a hierarchical sensor network: a) a distance-aware clustering where nodes are clustered based on their distance and the residual energy and b) a service-aware clustering where the nodes of a sensor network are clustered according to their service offered to the network and their residual energy. These approaches are implemented into a family of routing protocols referred to as EOCIT (Energy Optimization using Clustering Techniques) which combines sensor node energy location and service awareness to achieve good network performance. Finally, building upon the Ant Colony Optimization System (ACS), Multipath Routing protocol based on Ant Colony Optimization approach for Wireless Sensor Networks (MRACO) is proposed as a novel multipath routing protocol that finds energy efficient routing paths for sensor readings dissemination from the cluster heads to the sink/base station of a hierarchical sensor network. Our simulation results reveal the relative efficiency of the newly proposed approaches compared to selected related routing protocols in terms of sensor network lifetime maximization.

Předložená disertační práce řeší komplexní mechatronický návrh autonomního termoelektrického zdroje energie pro letecké aplikace. Na základě dostupných zdrojů a literatury práce popisuje současný stav problematiky. V práci jsou prezentovány simulační modely MEMS termoelektrických článků, které jsou ověřeny experimentálním testováním a hodnotami dostupnými od výrobce. Na základě metodiky model-besed design byly navrženy a vyrobeny tři demonstrátory. Jejich vlastnosti byly testovány v reálných podmínkách na letecké pohonné jednotce.

Hardware-software co-design techniques are very suitable to develop the next generation of sensornet applications, which have high computational demands. By making use of a low power FPGA, the peak computational performance of a sensor node can be improved without significant degradation of the standby power dissipation. In this contribution, we present a methodology and tool to enable hardware/software co-design for sensor node application development. We present the integration of nesC, a sensornet programming language, with GEZEL, an easy-to-use hardware description language. We describe the hardware/software interface at different levels of abstraction: at the level of the design language, at the level of the co-simulator, and in the hardware implementation. We use a layered, uniform approach that is particularly suited to deal with the heterogeneous interfaces typically found on small embedded processors. We illustrate the strengths of our approach by means of a prototype application: the integration of a hardware-accelerated crypto-application in a nesC application. / Master of Science