Blackout

About: Blackout is a research topic. Over the lifetime, 2088 publications have been published within this topic receiving 30433 citations.

Off the Beaten Path: Resiliency and Associated Risk

Abstract: Large-scale electric grids remain an indispensable critical infrastructure, and the vast majority of people will continue to receive most of their electric energy from such grids for decades to come. The impacts of the loss of a portion of the electric grid range from minor inconveniences for most users when the outage is on a small scale and short lived to potentially catastrophic situations when the blackout covers a large region for a long duration. Since the inception of the first electric grids in the 1880s, much has been done to reduce the likelihood and extent of blackouts. However, they cannot be totally eliminated, and there is usually a tradeoff between reduced blackout risk and increased cost. The focus of this article is on costeffective ways to reduce this risk and, consequently, improve resiliency.

QoE and energy efficiency aware resource allocation for OFDM systems in group mobility environments

Abstract: The global information and communication technology industry is a fast growing contributor to the electrical energy consumption, especially for the base stations, accounting for a substantial amount of the energy use. Inherently, a resource allocation strategy including subchannels blackout would reduce energy consumption. In this paper, energy efficient resource allocation algorithms are addressed for the OFDM system in group mobility environments, suffering from high intercarrier interference. We first propose the subchannels blackout scheme to save energy implicitly without performance degradation by turning off certain subchannels when transmitting signals. Then, resource allocation scheme in combination with subchannels blackout scheme is developed, consisting of intergroup subchannels allocation and inner-group subchannels blackout. Its advantage is twofold. i Energy consumption is reduced obviously; ii intercarrier interference is decreased and channel quality is enhanced simultaneously. However, the original transmit rate decreases with the decrease of active resources. We also prove under subchannels blackout scheme, achieved throughput and perceptual quality of experience QoE are quasiconcave in energy saving percentage, which reflects the number of blackout subchannels. We then present two energy efficient resource allocation algorithms. Both algorithms focus on the optimal solution by using an iteration method. The difference lies in the objective. One tries for energy consumption minimization above the satisfactory QoE level, but the other aims to maximize QoE perceived by users. Numerical results confirm the theoretical findings and demonstrate the promising energy-saving capability with satisfying QoE of the proposed resource allocation schemes. Copyright © 2013 John Wiley & Sons, Ltd.

Plasma telemetry in hypersonic flight

Abstract: Problems associated with telemetry blackout caused by the plasma sheath surrounding a hypersonic vehicle are addressed. In particular, the critical nature of overcoming this limitation for test and evaluation purposes is detailed. Since the telemetry blackout causes great concern for atmospheric cruise vehicles, ballistic missiles, and reentry vehicles, there have been many proposed approaches to solving the problem. This paper overviews aerodynamic design methodologies, for which the required technologies are only now being realized, which may allow for uninterrupted transmission through a plasma sheath. The severity of the signal attenuation is dependent on vehicle configuration, trajectory, flightpath, and mission.