3,893 research outputs found
Separating Gravitational Wave Signals from Instrument Artifacts
Central to the gravitational wave detection problem is the challenge of
separating features in the data produced by astrophysical sources from features
produced by the detector. Matched filtering provides an optimal solution for
Gaussian noise, but in practice, transient noise excursions or ``glitches''
complicate the analysis. Detector diagnostics and coincidence tests can be used
to veto many glitches which may otherwise be misinterpreted as gravitational
wave signals. The glitches that remain can lead to long tails in the matched
filter search statistics and drive up the detection threshold. Here we describe
a Bayesian approach that incorporates a more realistic model for the instrument
noise allowing for fluctuating noise levels that vary independently across
frequency bands, and deterministic ``glitch fitting'' using wavelets as
``glitch templates'', the number of which is determined by a trans-dimensional
Markov chain Monte Carlo algorithm. We demonstrate the method's effectiveness
on simulated data containing low amplitude gravitational wave signals from
inspiraling binary black hole systems, and simulated non-stationary and
non-Gaussian noise comprised of a Gaussian component with the standard
LIGO/Virgo spectrum, and injected glitches of various amplitude, prevalence,
and variety. Glitch fitting allows us to detect significantly weaker signals
than standard techniques.Comment: 21 pages, 18 figure
Enabling high confidence detections of gravitational-wave bursts
With the advanced LIGO and Virgo detectors taking observations the detection
of gravitational waves is expected within the next few years. Extracting
astrophysical information from gravitational wave detections is a well-posed
problem and thoroughly studied when detailed models for the waveforms are
available. However, one motivation for the field of gravitational wave
astronomy is the potential for new discoveries. Recognizing and characterizing
unanticipated signals requires data analysis techniques which do not depend on
theoretical predictions for the gravitational waveform. Past searches for
short-duration un-modeled gravitational wave signals have been hampered by
transient noise artifacts, or "glitches," in the detectors. In some cases, even
high signal-to-noise simulated astrophysical signals have proven difficult to
distinguish from glitches, so that essentially any plausible signal could be
detected with at most 2-3 level confidence. We have put forth the
BayesWave algorithm to differentiate between generic gravitational wave
transients and glitches, and to provide robust waveform reconstruction and
characterization of the astrophysical signals. Here we study BayesWave's
capabilities for rejecting glitches while assigning high confidence to
detection candidates through analytic approximations to the Bayesian evidence.
Analytic results are tested with numerical experiments by adding simulated
gravitational wave transient signals to LIGO data collected between 2009 and
2010 and found to be in good agreement.Comment: 15 pages, 6 figures, submitted to PR
Colaboratory: Design Collaboration for The Greater Good
Graphic design is a powerful tool, which has the power to shift perspective and create an impact. A recent shift in the design world has graphic designers using their skill sets to address complex social problems, to engage their audience in new ways that bring awareness to a social issue for the greater good of society. This thesis examines how graphic design collaboration ignites social change within a community and inspires transformation in human behavior. It explores how designing for the greater good impacts our society; and how these collaborative experiences improve the community and clients they serve. This thesis will also showcase how design can benefit the greater good through a multi-disciplinary design think-tank devoted to fostering experience by stimulating creativity through collaboration of students with actual clients
The Jungle Down the Street, the Town Across the Bridge, All is Very Well
The Jungle Down the Street, the Town Across the Bridge, All is Very Well is a series of short, nonfiction essays attempting to paint several portraits—regional, ecological, familial, and personal. Focused around the town of Apalachicola, Florida, it addresses themes of family, folklore, tragedy, and the “New Sublime,” or the feeling of wonder at the beauty that precedes an inevitable end. The piece attempts to blend multiple narrative and thematic arcs through the use of humor, anecdote, and historical research
Extreme distributions of ground winds /3 to 150 meters/ at Cape Kennedy, Florida
Statistical analysis of wind distribution probabilities at Cape Kenned
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