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In this paper, we propose a mechanism to ensure the proper functioning of a wireless sensor network (WSN) in the presence of static and proactive jammer within the network. Existing research works have primarily focused on the detection of jammer node within the network and ameliorating its consequent effects on the network. However, these countermeasures to mitigate the effect of the jammer suffer from certain limitations as WSNs are primarily resource constrained and most of the countermeasures are computationally intensive. The objective of this paper is to prevent the disruption of the network in the presence of jamming by bypassing the jammed zone and setting up alternative paths. The alternative paths are chosen with the maximum link quality in order to maintain the quality of service of the network even after jamming. This paper proposes Link-quality Aware Path SElection (LAPSE) algorithm that chooses alternative paths based on the optimal link quality. LAPSE is based on optimal decision rule and its design considers the fallible nature of the nodes while choosing/rejecting a particular link. Finally, the performance of the proposed algorithm, LAPSE, is evaluated in terms of the network parameters—packet delivery rate, network throughput, transmission energy, node lifetime, and network lifetime. Results indicate that the performance of LAPSE is significantly better than the existing jamming avoidance algorithms. [ABSTRACT FROM PUBLISHER]

In response to economic, environmental and national security factors, nations are diversifying their energy extraction and generation opportunities through the development of cleaner, more efficient and renewable technologies. These developments are expanding the geographic footprint of energy infrastructure and encroaching on the aviation transportation system. The aviation industry is concerned that current practices are not reducing the adverse impacts of energy projects on the safety of airport operations and navigable airspace. In response, the Transportation Research Board's Airport Cooperative Research Program (ACRP), an industry-driven, applied research programme of the National Academy of Sciences based in the USA, directed research to better understand the risk of airspace impacts from energy technologies and to develop best practices for aviation safety associated with planning, developing and constructing energy projects. The research focused on energy technologies that are currently being developed, including solar photovoltaic, concentrating solar power, wind power, oil and natural gas extraction, steam-generated power production and electricity transmission. Each technology produces different types of impacts on airports and navigable airspace including physical penetration of airspace, radar interference, glare and thermal turbulence. The research findings, drawing on information from Australia, the UK and the USA, are presented as best practices, organised by technology, and include general siting and design criteria for each. The Guidebook represents a comprehensive resource for aviation and energy industry professionals with information to improve energy technology siting to enable nations to meet domestic energy production needs while ensuring a safe and efficient aviation transportation system. [ABSTRACT FROM AUTHOR]

This paper proposes novel techniques for scheduling radar dwells in phased array radar systems. In order to handle complex physical characteristics such as dwell interleaving, transmitting duty cycle constraint, and energy constraint, we propose a notion of schedulability envelope. The schedulability envelope designed offline hides the details of complex radar dwell scheduling and provides a simple measure for the schedulability check. Using the schedulability envelope, the proposed technique can efficiently perform the admission control for dynamic target tracking tasks. The simulation results show that the proposed approach can significantly improve the system utilization by taking advantage of dwell interleaving while guaranteeing the schedulability and physical constraints. [ABSTRACT FROM AUTHOR]

A wavelet-based method for the lossy compression of single-look complex synthetic aperture radar (SAR) data is presented, together with a comparison between SAR data compressions in Cartesian and polar coordinates. It shows that the compression of complex SAR data in polar coordinates has smaller amplitude and phase errors than in Cartesian coordinates. The compression in polar coordinates requires bit allocation processing between amplitude and phase. This is achieved by phase scaling before compression, and the method is given for scale factor calculation. [ABSTRACT FROM AUTHOR]