Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: Xiang-Gen Xia, Dept. of Electrical & Computer Engineering. Includes bibliographical references.

This thesis investigates the feasibility of using gestures as a means of control for localizing three dimensional (3D) sound sources in a distributed immersive audio system. A prototype system was implemented and tested which uses state of the art technology to achieve the stated goals. A Windows Kinect is used for gesture recognition which translates human gestures into control messages by the prototype system, which in turn performs actions based on the recognized gestures. The term distributed in the context of this system refers to the audio processing capacity. The prototype system partitions and allocates the processing load between a number of endpoints. The reallocated processing load consists of the mixing of audio samples according to a specification. The endpoints used in this research are XMOS AVB endpoints. The firmware on these endpoints were modified to include the audio mixing capability which was controlled by a state of the art audio distribution networking standard, Ethernet AVB. The hardware used for the implementation of the prototype system is relatively cost efficient in comparison to professional audio hardware, and is also commercially available for end users. the successful implementation and results from user testing of the prototype system demonstrates how it is a feasible option for recording the localization of a sound source. The ability to partition the processing provides a modular approach to building immersive sound systems. This removes the constraint of a centralized mixing console with a predetermined speaker configuration.

Over-the-air programming systems for wireless sensor networks have drawbacks that stem from fundamental limitations in the hardware used in current sensor nodes. Also, advances in technology make it feasible to use capacitors as the sole energy storage mechanism for sensor nodes using energy harvesting, but most current designs require additional electronics. These two considerations led to the design of a new sensor node. A microcontroller was chosen that meets the Popek and Goldberg virtualization requirements. The hardware design for this new sensor node is presented, as well as a preliminary operating system. The prototypes are tested, and demonstrated to be sustainable with a capacitor and solar panel. The issue of capacitor leakage is considered and measured.

This dissertation presents methods of extending the network lifetime of multi-hop wireless sensor networks (WSNs) through routing that uses cooperative transmission (CT), referred to as cooperative routing. CT can have a signal-to-noise ratio (SNR) advantage over non-CT schemes through cooperative diversity and simple aggregation of transmit power, and one of its abilities is to extend the communication range of a wireless device using this SNR advantage. In this research, we use the range-extension ability of CT as a tool to mitigate the energy-hole problem of multi-hop WSNs and extend the network lifetime. The main contributions of this research are (i) an analytical model for a cooperative routing protocol with a deployment method, (ii) cooperative routing protocols that can extend the network lifetime, and (iii) formulating the lifetime-optimization problem for cooperative routing. The analytical model developed in this research theoretically proves that, in a situation where non-CT routing cannot avoid the energy-hole problem, our CT method can solve the problem. PROTECT, a CT method based on the analytical model, provides a very simple way of doing cooperative routing and can improve the lifetime of non-CT networks significantly. REACT, a cooperative routing protocol that uses the energy information of nodes, overcomes some of the limitations of PROTECT and can be applied to any existing non-CT routing protocol to improve the network lifetime. Using REACT and analytical approaches, we also show that cooperative routing can be beneficial in multi-hop energy-harvesting WSNs. By formulating and solving the lifetime-optimization problem of cooperative routing, which requires a much more sophisticated formulation than that of non-CT routing, we explore the optimal lifetime bounds and behaviors of cooperative routing. Finally, we study and design online cooperative routing methods that can perform close to the optimal cooperative routing.

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.

No description available.

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.

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.

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