Lundquist S.Y.,New Mexico Institute of Mining and Technology |
Paiton D.M.,Los Alamos National Laboratory |
Nowers B.M.,New Mexico Institute of Mining and Technology |
Schultz P.F.,New Mexico Consortium |
And 3 more authors.
Proceedings of the International Joint Conference on Neural Networks
Wireless networks of biologically inspired distributed sensors (BIDS) are hypothesized to enable improved overall detection accuracy using ultra-low power and low bandwidth spike-based communication between nodes. Unlike traditional sensor networks, in which nodes communicate via digital protocols that require precise decoding of binary signal packets, BIDS nodes communicate by broadcasting generic radio frequency pulses, or spikes. Individual BIDS nodes are modeled after leaky integrate-and-fire (LIF) neurons, in which both filtered sensory signals and inputs from other BIDS nodes are accumulated as capacitive charge that decays with a characteristic time constant. A BIDS node itself broadcasts a spike whenever its internal state exceeds a threshold value. Here we present detailed simulations of a BIDS network designed to detect a moving target-modeled as a pure acoustic tone with a translating origin-against a background of 1/f noise. In the absence of a target, the average internal state is well below threshold and noise-induced spikes recruit little additional activity. In contrast, the presence of a target pushes the average internal state closer to threshold, such that each spike is now able to recruit additional spikes, leading to a chain reaction. Our results show that while individual BIDS nodes may be noisy and unreliable, a network of BIDS nodes is capable of highly reliable detection even when the signal-to-noise ratio (SNR) on individual nodes is low. We demonstrate that collective computation between nodes supports improved detection accuracy in a manner that is extremely robust to the damage or loss of individual nodes. © 2013 IEEE. Source
News Article | March 22, 2016
The Australian CleanTech Index rose from 42.97 to 43.89 over the month of February recording a 2.2% gain. This compared to the S&P ASX200 loss of 2.5% and the S&P ASX Small Ordinaries Index gain of 0.7%. The Australian CleanTech 20 rose 2.3% for the month. The CleanTech Index continues to outperform the wider market over each of the longer periods reported in the table below. The 12-month performance now leads the ASX200 by 11.1%. The best performing sub-indices for the month were the Australian Renewable Energy Index with a 3.7% gain and the Australian Waste Index with a 3.6% gain. The weakest sub-index through February was the Australian Environment Index recording a loss of 4.0%. The market capitalisation of the 62 stocks in the Australian CleanTech Index is A$16.7 billion down from the March 2015 record of $18.9 billion but a long way up from its low of A$6.2 billion in July 2012. The month’s performance included 9 companies with gains of more than 10%. The greatest percentage gains were recorded by HRL Holdings (HRL), Neometals (NMT) and RedFlow (RFX). The greatest market capitalisation gain was recorded by Meridian Energy (MEZ). These gains were partially offset by 10 companies recording losses of more than 10% led by GO Energy Group (GOE), Kalina Power (KPO), Traffic Technologies (TTI) and Enerji (ERJ). The greatest market capitalisation loss was recorded by Mighty River Power (MYT). Get CleanTechnica’s 1st (completely free) electric car report → “Electric Cars: What Early Adopters & First Followers Want.” Come attend CleanTechnica’s 1st “Cleantech Revolution Tour” event → in Berlin, Germany, April 9–10. Keep up to date with all the hottest cleantech news by subscribing to our (free) cleantech newsletter, or keep an eye on sector-specific news by getting our (also free) solar energy newsletter, electric vehicle newsletter, or wind energy newsletter.
Defer E.,French National Center for Scientific Research |
Pinty J.-P.,French National Center for Scientific Research |
Coquillat S.,French National Center for Scientific Research |
Martin J.-M.,French National Center for Scientific Research |
And 25 more authors.
Atmospheric Measurement Techniques
The PEACH project (Projet en Electricité Atmosphérique pour la Campagne HyMeX - the Atmospheric Electricity Project of the HyMeX Program) is the atmospheric electricity component of the Hydrology cycle in the Mediterranean Experiment (HyMeX) experiment and is dedicated to the observation of both lightning activity and electrical state of continental and maritime thunderstorms in the area of the Mediterranean Sea. During the HyMeX SOP1 (Special Observation Period) from 5 September to 6 November 2012, four European operational lightning locating systems (ATDnet, EUCLID, LINET, ZEUS) and the HyMeX lightning mapping array network (HyLMA) were used to locate and characterize the lightning activity over the northwestern Mediterranean at flash, storm and regional scales. Additional research instruments like slow antennas, video cameras, microbarometer and microphone arrays were also operated. All these observations in conjunction with operational/research ground-based and airborne radars, rain gauges and in situ microphysical records are aimed at characterizing and understanding electrically active and highly precipitating events over southeastern France that often lead to severe flash floods. Simulations performed with cloud resolving models like Meso-NH and Weather Research and Forecasting are used to interpret the results and to investigate further the links between dynamics, microphysics, electrification and lightning occurrence. Herein we present an overview of the PEACH project and its different instruments. Examples are discussed to illustrate the comprehensive and unique lightning data set, from radio frequency to acoustics, collected during the SOP1 for lightning phenomenology understanding, instrumentation validation, storm characterization and modeling. © Author(s) 2015. Source
Soula S.,CNRS Laboratory for Aerology |
Defer E.,French National Center for Scientific Research |
Fullekrug M.,University of Bath |
Van Der Velde O.,Polytechnic University of Catalonia |
And 9 more authors.
Journal of Geophysical Research: Atmospheres
During the night of 22-23 October 2012, together with the Hydrology cycle in the Mediterranean eXperiment (HyMeX) Special Observation Period 1 campaign, optical observations of sprite events were performed above a leading stratiform Mesoscale Convective System in southeastern France. The total lightning activity of the storm was monitored in three dimensions with the HyMeX Lightning Mapping Array. Broadband Extremely Low Frequency/Very Low Frequency records and radar observations allowed characterizing the flashes and the regions of the cloud where they propagated. Twelve sprite events occurred over the stratiform region, during the last third of the lightning activity period, and well after the coldest satellite-based cloud top temperature (-62°C) and the maximum total lightning flash rate (11 min-1). The sprite-producing positive cloud-to-ground (SP + CG) strokes exhibit peak current from 14 to 247 kA, Charge Moment Changes (CMC) from 625 to 3086 C km, and Impulsive CMC (iCMC) between 242 and 1525 C km. The +CG flashes that do not trigger sprites are initiated outside the main convective core, have much lower CMC values, and in average, shorter durations, lower peak currents, and shorter distances of propagation. The CMC appears to be the best sprite predictor. The delay between the parent stroke and the sprite allows classifying the events as short delayed (<20 ms) and long delayed (>20 ms). All long-delayed sprites, i.e., most of the time carrot sprites, are produced by SP + CG strokes with low iCMC values. All SP + CG flashes initiate close to the convective core and generate leaders in opposite directions. Negative leaders finally propagate toward lower altitudes, within the stratiform region that coincides with the projected location of the sprite elements. © 2015. American Geophysical Union. All Rights Reserved. Source
Santoro F.G.,MRO Inc |
Olivares A.M.,MRO Inc |
Salcido C.D.,MRO Inc |
Jimenez S.R.,MRO Inc |
And 11 more authors.
Proceedings of SPIE - The International Society for Optical Engineering
NESSI: the New Mexico Tech Extrasolar Spectroscopic Survey Instrument is a ground-based multi-object spectrograph that operates in the near-infrared. It will be installed on one of the Nasmyth ports of the Magdalena Ridge Observatory (MRO) 2.4-meter Telescope. NESSI operates stationary to the telescope fork so as not to produce differential flexure between internal opto-mechanical components during or between observations. In this paper we report on NESSI's detailed mechanical and opto-mechanical design, and the planning for mechanical construction, assembly, integration and verification. © 2012 SPIE. Source