248 research outputs found
An Integer Linear Programming Solution to the Telescope Network Scheduling Problem
Telescope networks are gaining traction due to their promise of higher
resource utilization than single telescopes and as enablers of novel
astronomical observation modes. However, as telescope network sizes increase,
the possibility of scheduling them completely or even semi-manually disappears.
In an earlier paper, a step towards software telescope scheduling was made with
the specification of the Reservation formalism, through the use of which
astronomers can express their complex observation needs and preferences. In
this paper we build on that work. We present a solution to the discretized
version of the problem of scheduling a telescope network. We derive a solvable
integer linear programming (ILP) model based on the Reservation formalism. We
show computational results verifying its correctness, and confirm that our
Gurobi-based implementation can address problems of realistic size. Finally, we
extend the ILP model to also handle the novel observation requests that can be
specified using the more advanced Compound Reservation formalism.Comment: Accepted for publication in the refereed conference proceedings of
the International Conference on Operations Research and Enterprise Systems
(ICORES 2015
Dual Adaptive Recumbent Trike
The DART team\u27s objective was to develop a tandem recumbent tricycle that would be economical, easy to build, and adaptable. This would involve designing, building and testing the tricycle
A novel eccentricity parameterization for transit-only models
We present a novel eccentricity parameterization for transit-only fits that
allows us to efficiently sample the eccentricity and argument of periastron,
while being able to generate a self-consistent model of a planet in a Keplerian
orbit around its host star. With simulated fits of 330 randomly generated
systems, we demonstrate that typical parameterizations often lead to inaccurate
and overly precise determinations of the planetary eccentricity. However, our
proposed parameterization allows us to accurately -- and often precisely --
recover the eccentricity for the simulated planetary systems with only transit
data available.Comment: 10 pages, 7 figures, submitted to PAS
Double Jeopardy: Minority Stress and the Influence of Transgender Identity and Race/Ethnicity
This study assessed gender and racial/ethnic differences in gender-related discrimination and psychological distress within a sample of transgender and gender nonconforming individuals. Prior research suggests transgender individuals with multiple minority statuses experience higher psychological stress than their singly disadvantaged counterparts, and both minority race/ethnicity and transgender minorities experience more frequent and severe forms of discrimination than white and cisgender individuals. Using data from a convenience sample of 101 self-identified transgender and gender nonconforming adults recruited through LGBTQ+ organizations from across North America, I analyzed the relationship between race/ethnicity, gender-related minority stress, and psychological distress. Gender-related discrimination and gender-related victimization did not significantly differ by gender identity or race/ethnicity. However, racial/ethnic minorities reported significantly higher psychological distress than white participants. While being a racial/ethnic minority may not directly worsen one\u27s experiences with gender-related discrimination and victimization, other factors, such as experiences with race related discrimination, may contribute to disparities in mental health
Analytic Approximations for Transit Light Curve Observables, Uncertainties, and Covariances
The light curve of an exoplanetary transit can be used to estimate the
planetary radius and other parameters of interest. Because accurate parameter
estimation is a non-analytic and computationally intensive problem, it is often
useful to have analytic approximations for the parameters as well as their
uncertainties and covariances. Here we give such formulas, for the case of an
exoplanet transiting a star with a uniform brightness distribution. We also
assess the advantages of some relatively uncorrelated parameter sets for
fitting actual data. When limb darkening is significant, our parameter sets are
still useful, although our analytic formulas underpredict the covariances and
uncertainties.Comment: 33 pages, 14 figure
Transit Analysis Package (TAP and autoKep): IDL Graphical User Interfaces for Extrasolar Planet Transit Photometry
We present an IDL graphical user interface-driven software package designed
for the analysis of extrasolar planet transit light curves. The Transit
Analysis Package (TAP) software uses Markov Chain Monte Carlo (MCMC) techniques
to fit light curves using the analytic model of Mandel and Agol (2002). The
package incorporates a wavelet based likelihood function developed by Carter
and Winn (2009) which allows the MCMC to assess parameter uncertainties more
robustly than classic chi-squared methods by parameterizing uncorrelated
"white" and correlated "red" noise. The software is able to simultaneously
analyze multiple transits observed in different conditions (instrument, filter,
weather, etc). The graphical interface allows for the simple execution and
interpretation of Bayesian MCMC analysis tailored to a user's specific data set
and has been thoroughly tested on ground-based and Kepler photometry. AutoKep
provides a similar GUI for the preparation of Kepler MAST archive data for
analysis by TAP or any other analysis software. This paper describes the
software release and provides instructions for its use.Comment: 8 pages, 2 figure
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