Suchergebnisse

The detection and classification of subsurface improvised explosive devices (IEDs) remains one of the most pressing military and civilian problems worldwide. These IEDs are often intentionally made with either very small metallic parts or less-conducting parts in order to evade low-frequency electromagnetic induction (EMI) sensors, or metal detectors, which operate at frequencies of 50 kHz or less. Recently, high-frequency electromagnetic induction (HFEMI), which extends the established EMI frequency range above 50 kHz to 20 MHz and bridges the gap between EMI and ground-penetrating radar frequencies, has shown promising results related to detecting and identifying IEDs. In this higher frequency range, less-conductive targets display signature inphase and quadrature responses similar to higher conducting targets in the LFEMI range. IED constituent parts, such as carbon rods, small pressure plates, conductivity voids, low metal content mines, and short wires respond to HFEMI but not to traditional low-frequency EMI (LFEMI). Results from recent testing over mock-ups of less-conductive IEDs or their components show distinctive HFEMI responses, suggesting that this new sensing realm could augment the detection and discrimination capability of established EMI technology. In this paper, we present results of using the HFEMI sensor over IED-like targets at the Fort AP Hill test site. We show that results agree with numerical modeling thus providing motives to incorporate sensing at these frequencies into traditional EMI and/or GPR-based sensors.

A pioneering account of the surging global tide of market power-and how it stifles workers around the worldIn an era of technological progress and easy communication, it might seem reasonable to assume that the world's working people have never had it so good. But wages are stagnant and prices are rising, so that everything from a bottle of beer to a prosthetic hip costs more. Economist Jan Eeckhout shows how this is due to a small number of companies exploiting an unbridled rise in market power-the ability to set prices higher than they could in a properly functioning competitive marketplace. Drawing on his own groundbreaking research and telling the stories of common workers throughout, he demonstrates how market power has suffocated the world of work, and how, without better mechanisms to ensure competition, it could lead to disastrous market corrections and political turmoil.The Profit Paradox describes how, over the past forty years, a handful of companies have reaped most of the rewards of technological advancements-acquiring rivals, securing huge profits, and creating brutally unequal outcomes for workers. Instead of passing on the benefits of better technologies to consumers through lower prices, these "superstar" companies leverage new technologies to charge even higher prices. The consequences are already immense, from unnecessarily high prices for virtually everything, to fewer startups that can compete, to rising inequality and stagnating wages for most workers, to severely limited social mobility.A provocative investigation into how market power hurts average working people, The Profit Paradox also offers concrete solutions for fixing the problem and restoring a healthy economy