9,789 research outputs found
On estimating the phase of a periodic waveform in additive Gaussian noise, part 3
Motivated by advances in signal processing technology that support more complex algorithms, researchers have taken a new look at the problem of estimating the phase and other parameters of a nearly periodic waveform in additive Gaussian noise, based on observation during a given time interval. Parts 1 and 2 are very briefly reviewed. In part 3, the actual performances of some of the highly nonlinear estimation algorithms of parts 1 and 2 are evaluated by numerical simulation using Monte Carlo techniques
Investigations in space communications theory, including topics related to random processes, filtering, telemetry Semiannual status report, 1 Oct. 1966 - 31 Mar. 1967
Random processes, filtering, and telemetry problems in space communications theor
Detector characterization, electronic-recoil energy scale and astrophysical independent results in XENON100
For over three years, the XENON100 experiment set the benchmark sensitivity for the weakly interacting massive particle (WIMP) dark matter candidate, with a crosssection of 2.0 x 10-45 cm2 at 55 GeV for spin independent interactions. In this thesis various analysis are introduced to extend the dark matter search with the XENON100 detector. For the science data taken in 2013/2014, studies on the light and charge yield as well as an optimized correction for the secondary scintillation signal is introduced, resulting in an increased energy resolution of the detector. Secondly, a method to determine the charge yield for electromagnetic interactions in liquid xenon with the XENON100 detector is developed and results are presented. Finally, a method is used to derive bounds on the WIMP - nucleus interactions, free of astrophysical uncertainties
Trade as an Engine of Creative Destruction Mexico experience with Chinese competition
This paper exploits the surge in Chinese exports from 1994 to 2004 as a natural experiment to evaluate the effects of a unilateral low wage trade and competition shock to producers in Mexico. We find that this shock causes selection at both firm and product levels as its impact is highly heterogeneous both on the intensive and extensive margins. Sales of smaller plants and more marginal products are compressed and are more likely to cease, while larger plants and products exhibit an opposite response. Similar results hold both for the domestic market and for competition facing Mexican exporters in a third market (i.e. the United States).China, Mexico, multi-product-firm, trade shock
Trade as an Engine of Creative Destruction: Mexican Experience with Chinese Competition
This paper exploits the surge in Chinese exports from 1994 to 2004 as a natural experiment to evaluate the effects of a unilateral low wage trade and competition shock to producers in Mexico. We find that this shock causes selection at both firm and product levels as its impact is highly heterogeneous both on the intensive and extensive margins. Sales of smaller plants and more marginal products are compressed and are more likely to cease, while larger plants and products exhibit an opposite response. Similar results hold both for the domestic market and for competition facing Mexican exporters in a third market (i.e. the United States).China, Mexico, multi-product-firm, trade shock
High-precision Atomic Physics Laboratories in Space: White Dwarfs and Subdwarfs
The 21st European Workshop on White Dwarfs was held in Austin, TX from July 23rd to 27th of 2018Stellar atmospheres are prime laboratories to determine
atomic properties of highly ionized species.
Reliable opacities are crucial ingredients for the
calculation of stellar atmospheres of white dwarfs
and subdwarfs. A detailed investigation on the
precision of many iron-group oscillator strengths
is still outstanding. To make progress, we used
the Hubble Space Telescope Imaging Spectrograph
to measure high-resolution spectra of three hot
subdwarfs that exhibit extremely high iron-group
abundances. The predicted relative strengths of
the identified lines are compared with the observations
to judge the quality of Kurucz’s line data
and to determine correction factors for abundance
determinations of the respective elements.Astronom
Transonic flutter study of a wind-tunnel model of a supercritical wing with/without winglet
The model was a 1/6.5-size, semipan version of a wing proposed for an executive-jet-transport airplane. The model was tested with a normal wingtip, a wingtip with winglet, and a normal wingtip ballasted to simulate the winglet mass properties. Flutter and aerodynamic data were acquired at Mach numbers (M) from 0.6 to 0.95. The measured transonic flutter speed boundary for each wingtip configuration had roughly the same shape with a minimum flutter speed near M=0.82. The winglet addition and wingtip mass ballast decreased the wing flutter speed by about 7 and 5 percent, respectively; thus, the winglet effect on flutter was more a mass effect than an aerodynamic effect
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