248 research outputs found

    An Integer Linear Programming Solution to the Telescope Network Scheduling Problem

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    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

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    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

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    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

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    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

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    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

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    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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