25,762 research outputs found

    Upper Limits from Counting Experiments with Multiple Pipelines

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    In counting experiments, one can set an upper limit on the rate of a Poisson process based on a count of the number of events observed due to the process. In some experiments, one makes several counts of the number of events, using different instruments, different event detection algorithms, or observations over multiple time intervals. We demonstrate how to generalize the classical frequentist upper limit calculation to the case where multiple counts of events are made over one or more time intervals using several (not necessarily independent) procedures. We show how different choices of the rank ordering of possible outcomes in the space of counts correspond to applying different levels of significance to the various measurements. We propose an ordering that is matched to the sensitivity of the different measurement procedures and show that in typical cases it gives stronger upper limits than other choices. As an example, we show how this method can be applied to searches for gravitational-wave bursts, where multiple burst-detection algorithms analyse the same data set, and demonstrate how a single combined upper limit can be set on the gravitational-wave burst rate.Comment: 26 pages (CQG style), 8 figures. Added study of robustness of limits

    Homelessness and Substance Abuse: Is Mandatory Treatment the Solution?

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    For the government to be successful in addressing homelessness, it must focus on the link between homelessness and substance abuse. In New York City and elsewhere, advocates are reluctant to publicize the connection between substance abuse and homelessness. Federal laws and programs that attempt to deal with homelessness, such as welfare, Social Security, federal housing laws, and the McKinney Act and other various federal acts do not provide a comprehensive approach to treatment of those who are both homeless and substance abusers. Because the Supreme Court has held that the Constitution does not provide a right to shelter, advocates have turned to state court. Unfortunately, few state constitutions have constitutional language providing for a right of the poor to care and housing. Additionally, the substance abuse problems seen in the homeless complicate any state statutes. This Article proposes a federal solution, arguing that the only long-term approach with any chance of achieving real success is a national remedy that includes treatment for substance abuse as a condition attached to housing

    Using the INSPIRAL program to search for gravitational waves from low-mass binary inspiral

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    The INSPIRAL program is the LIGO Scientific Collaboration's computational engine for the search for gravitational waves from binary neutron stars and sub-solar mass black holes. We describe how this program, which makes use of the FINDCHIRP algorithm (discussed in a companion paper), is integrated into a sophisticated data analysis pipeline that was used in the search for low-mass binary inspirals in data taken during the second LIGO science run.Comment: 11 pages, 3 figures, submitted to Classical and Quantum Gravity for the special issue of the GWDAW9 Proceeding

    Vetoes for Inspiral Triggers in LIGO Data

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    Presented is a summary of studies by the LIGO Scientific Collaboration's Inspiral Analysis Group on the development of possible vetoes to be used in evaluation of data from the first two LIGO science data runs. Numerous environmental monitor signals and interferometer control channels have been analyzed in order to characterize the interferometers' performance. The results of studies on selected data segments are provided in this paper. The vetoes used in the compact binary inspiral analyses of LIGO's S1 and S2 science data runs are presented and discussed.Comment: Submitted to Classical and Quantum Gravity for the GWDAW-8 proceeding

    Research on utilization of part task spatial orientation information in the dynamic simulator

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    Error and control efficiency analysis of pilots exposed to simulated pitch, roll, yaw, and altitude variation
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