3,665 research outputs found

    Applying Blockchain Solutions to Address Research Reproducibility and Enable Scientometric Analysis

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    A worldwide reproducibility crisis around published scientific studies has gained attention from academics, journalists, and concerned citizens in recent decades. The inability to reliably reproduce experiments from scholarly research—especially in areas of high- impact science—has far-reaching social and economic implications. Fraud may seem an obvious culprit, but in our data-intensive world, vague methods, unclear standards, and even accidental mismanagement of digital resources can all be contributing factors. Reproducibility is an area of increasing focus within the scientometrics community and looking to emerging technologies to help mitigate reproducibility challenges makes practical sense. In the Web 3.0 era, the promise of distributed computing, the maturation of cloud services, and other novel convergences point toward new ways to enable bibliometric reproducibility. Concurrently, research artifacts beyond the peer-reviewed article are growing in prominence—datasets, algorithms, pre-prints—all serve an expanding role in research dissemination and discovery. In this paper we present an overview of some new approaches—with particular focus on the benefits of blockchain-based software systems—for managing research information and improving scientometric reproducibility

    Validating gravitational-wave detections: The Advanced LIGO hardware injection system

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    Hardware injections are simulated gravitational-wave signals added to the Laser Interferometer Gravitational-wave Observatory (LIGO). The detectors’ test masses are physically displaced by an actuator in order to simulate the effects of a gravitational wave. The simulated signal initiates a control-system response which mimics that of a true gravitational wave. This provides an end-to-end test of LIGO’s ability to observe gravitational waves. The gravitational-wave analyses used to detect and characterize signals are exercised with hardware injections. By looking for discrepancies between the injected and recovered signals, we are able to characterize the performance of analyses and the coupling of instrumental subsystems to the detectors’ output channels. This paper describes the hardware injection system and the recovery of injected signals representing binary black hole mergers, a stochastic gravitational wave background, spinning neutron stars, and sine-Gaussians

    Laser driven launch vehicles for continuous access to space

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    The availability of megawatt laser systems in the next century will make laser launch systems from ground to orbit feasible and useful. Systems studies indicate launch capabilities of 1 ton payload per gigawatt laser power. Recent research in ground to orbit laser propulsion has emphasized laser supported detonation wave thrusters driven by repetitively pulsed infrared lasers. In this propulsion concept each laser repetition cycle consists of two pulses. A lower energy first pulse is used to vaporize a small amount of solid propellant and then after a brief expansion period, a second and higher energy laser pulse is used to drive a detonation wave through the expanded vapor. The results are reported of numerical studies comparing the detonation wave properties of various candidate propellants, and the simulation of thruster performance under realistic conditions. Experimental measurements designed to test the theoretical predictions are also presented. Measurements are discussed of radiance and opacity in absorption waves, and mass loss and momentum transfer. These data are interpreted in terms of specific impulse and energy conversion efficiency

    Converting InSAR- and GNSS-derived strain rate maps into earthquake hazard models for Anatolia

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    &amp;lt;p&amp;gt;Geodetic measurements of crustal deformation rates can provide important constraints on a region&amp;amp;#8217;s earthquake hazard that purely seismicity-based hazard models may miss. For example, geodesy might show that strain (or a deficit of seismic moment) is accumulating faster than the total rate at which known earthquakes have released it, implying that the long-term hazard may include larger earthquakes with long recurrence intervals (and/or temporal increases in seismicity rates). Conversely, the moment release rate in recent earthquakes might surpass the geodetic moment buildup rate, suggesting that the long-term-average earthquake activity and hazard may in fact may be more quiescent than might be estimated using the earthquake history alone. Such geodetic constraints, however, have traditionally been limited by poor spatial and/or temporal sampling, resulting in ambiguities about how the lithosphere accommodates strain in space and time that can bias estimates of the resulting hazard. High-resolution deformation maps address this limitation by imaging (rather than presuming and/or modelling) where and how deformation takes place. These maps are now within reach for the Alpine-Himalayan Belt &amp;amp;#8211; one of the most populous and seismically hazardous regions on Earth &amp;amp;#8211; thanks to the COMET-LiCSAR InSAR processing system, which performs large-scale automated processing and timeseries analysis of Sentinel-1 data provided by the EU&amp;amp;#8217;s Copernicus programme. We are pairing LiCSAR products with GNSS data to generate high-resolution maps of interseismic surface motion (velocity) and strain rate for the Anatolia region. Here we quantitively investigate what these strain rate distributions imply for seismic hazard in this region, using two approaches in parallel.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;First, building on previous work, we develop a fully probability-based method to pair geodesy and seismic catalogs to estimate the recurrence times of large, moderate and small earthquakes in a given region. We assume that earthquakes 1) obey a power-law magnitude-frequency distribution up to a maximum magnitude and 2) collectively release seismic moment at the same rate that we estimate it is accumulating from the strain rate maps. Iterating over various magnitude-frequency distributions and their governing parameters, and formally incorporating uncertainties in moment buildup rate and the magnitudes of recorded earthquakes, we build a probabilistic long-term-average earthquake model for Anatolia as a whole, including the most likely maximum earthquake magnitude. Second, we estimate how seismic hazard may vary from place to place within Anatolia. Using insights from dislocation models, we identify two key signatures of a locked fault in a strain rate field, allowing us to convert the newly developed strain maps to &amp;amp;#8220;effective fault maps.&amp;amp;#8221; Additionally, we explore how characteristics of earthquake magnitude-frequency distributions may scale with the rate of strain (or moment) buildup, and what these scaling relations imply for the distribution of hazard in Anatolia, using the seismic catalog to evaluate these hypotheses. We also explore the implications of our findings for seismic hazard and address how to expand these approaches to the Alpine-Himalaya Belt as a whole.&amp;lt;/p&amp;gt; </jats:p

    Plasduino: an inexpensive, general purpose data acquisition framework for educational experiments

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    Based on the Arduino development platform, Plasduino is an open-source data acquisition framework specifically designed for educational physics experiments. The source code, schematics and documentation are in the public domain under a GPL license and the system, streamlined for low cost and ease of use, can be replicated on the scale of a typical didactic lab with minimal effort. We describe the basic architecture of the system and illustrate its potential with some real-life examples.Comment: 11 pages, 10 figures, presented at the XCIX conference of the Societ\`a Italiana di Fisic

    Post Launch Calibration and Testing of the Advanced Baseline Imager on the GOES-R Satellite

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    The Geostationary Operational Environmental Satellite R (GOES-R) series is the planned next generation of operational weather satellites for the United State's National Oceanic and Atmospheric Administration. The first launch of the GOES-R series is planned for October 2016. The GOES-R series satellites and instruments are being developed by the National Aeronautics and Space Administration (NASA). One of the key instruments on the GOES-R series is the Advance Baseline Imager (ABI). The ABI is a multi-channel, visible through infrared, passive imaging radiometer. The ABI will provide moderate spatial and spectral resolution at high temporal and radiometric resolution to accurately monitor rapidly changing weather. Initial on-orbit calibration and performance characterization is crucial to establishing baseline used to maintain performance throughout mission life. A series of tests has been planned to establish the post launch performance and establish the parameters needed to process the data in the Ground Processing Algorithm. The large number of detectors for each channel required to provide the needed temporal coverage presents unique challenges for accurately calibrating ABI and minimizing striping. This paper discusses the planned tests to be performed on ABI over the six-month Post Launch Test period and the expected performance as it relates to ground tests

    Residential Stormwater Pond Maintenance and Outreach in the Lowcountry

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    2012 S.C. Water Resources Conference - Exploring Opportunities for Collaborative Water Research, Policy and Managemen

    Characterization of the stretched exponential trap-time distributions in one-dimensional coupled map lattices

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    Stretched exponential distributions and relaxation responses are encountered in a wide range of physical systems such as glasses, polymers and spin glasses. As found recently, this type of behavior occurs also for the distribution function of certain trap time in a number of coupled dynamical systems. We analyze a one-dimensional mathematical model of coupled chaotic oscillators which reproduces an experimental set-up of coupled diode-resonators and identify the necessary ingredients for stretched exponential distributions.Comment: 8 pages, 8 figure

    Parametric Amplification of Nonlinear Response of Single Crystal Niobium

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    Giant enhancement of the nonlinear response of a single crystal Nb sample, placed in {\it a pumping ac magnetic field}, has been observed experimentally. The experimentally observed amplitude of the output signal is about three orders of magnitude higher than that seen without parametric pumping. The theoretical analysis based on the extended double well potential model provides a qualitative explanation of the experimental results as well as new predictions of two bifurcations for specific values of the pumping signal.Comment: 6 pages, 10 figure
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