James Brownlow - Academia.edu (original) (raw)

Papers by James Brownlow

Quality and reliability engineering international, Jun 20, 2024

$Research paper thumbnail of Beta distributions: A computer program for probabilities and fractile points$

The need for statistical analysis often arises when data is in the form of a time series. This ty... more The need for statistical analysis often arises when data is in the form of a time series. This type of data is usually a collection of numerical observations made at specified time intervals. Two kinds of analysis may be performed on the data. First, the time series may be treated as a set of independent observations using a time domain analysis to derive the usual statistical properties including the mean, variance, and distribution form. Secondly, the order and time intervals of the observations may be used in a frequency domain analysis to examine the time series for periodicities. In almost all practical applications, the collected data is actually a mixture of the desired signal and a noise signal which is collected over a finite time period with a finite precision. Therefore, any statistical calculations and analyses are actually estimates. The Spectrum Analysis (SPA) program was developed to perform a wide range of statistical estimation functions. SPA can provide the data analyst with a rigorous tool for performing time and frequency domain studies. In a time domain statistical analysis the SPA program will compute the mean variance, standard deviation, mean square, and root mean square. It also lists the data maximum, data minimum, and the number of observations included in the sample. In addition, a histogram of the time domain data is generated, a normal curve is fit to the histogram, and a goodness-of-fit test is performed. These time domain calculations may be performed on both raw and filtered data. For a frequency domain statistical analysis the SPA program computes the power spectrum, cross spectrum, coherence, phase angle, amplitude ratio, and transfer function. The estimates of the frequency domain parameters may be smoothed with the use of Hann-Tukey, Hamming, Barlett, or moving average windows. Various digital filters are available to isolate data frequency components. Frequency components with periods longer than the data collection interval are removed by least-squares detrending. As many as ten channels of data may be analyzed at one time. Both tabular and plotted output may be generated by the SPA program. This program is written in FORTRAN IV and has been implemented on a CDC 6000 series computer with a central memory requirement of approximately 142K (octal) of 60 bit words. This core requirement can be reduced by segmentation of the program. The SPA program was developed in 1978.

The spectrum analysis (SPA) program is a general purpose digital computer program designed to aid... more The spectrum analysis (SPA) program is a general purpose digital computer program designed to aid in data analysis. The program does time and frequency domain statistical analyses as well as some preanalysis data preparation. The capabilities of the SPA program include linear trend removal and/or digital filtering of data, plotting and/or listing of both filtered and unfiltered data, time domain statistical characterization of data, and frequency domain statistical characterization of data.

NASA Tech Briefs, Apr 1, 1980

The influx of Gls after World War II to colleges and universities under the GI bill gave birth to... more The influx of Gls after World War II to colleges and universities under the GI bill gave birth to "adult education.' The Johnson-Brownlow Assessment Model was used to assess tools for evaluation of learning outcomes. Analysis of data collected show the following: Students and faculty showed strong correlation in understanding education as more than an accumulation of facts. Students and faculty differ in significant ways in evaluation preferences: students were found to favor assessments in the first compcnents of the JBAM (more direct examination of facts); faculty were found to prefer evaluation that assess the latter components of the model (evaluations of more abstract learning). Results indicate that the JBAM has validity for improving both the educational and evaluation processes. further work is warranted to determine how best to involve adult learners in educational processes specified at the higher-level skills addressed in the JBAM. Introduction Adult learners hav...

: Use a probability density function developed by Herschel Weil in 1953 to characterize TLE. The ... more : Use a probability density function developed by Herschel Weil in 1953 to characterize TLE. The method provided for independent normally distributed errors in both the along- and cross track axes. Purpose of the presentation: First- demonstrate Python code for estimation of CEP and/or CE90 values from a small data set. Secondly- present aspects of Python that are different from standard programming languages- python can be characterized as a cross between R and C++ with methods.

Public reporting burden for this collection of information is estimated to average 1 hour per res... more Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS.

A study is performed under NASA contract to evaluate data from an AN/FPS-16 radar installed for s... more A study is performed under NASA contract to evaluate data from an AN/FPS-16 radar installed for support of flight programs at Dryden Flight Research Facility of NASA Ames Research Center. The purpose of this study is to provide information necessary for improving post-flight data reduction and knowledge of accuracy of derived radar quantities. Tracking data from six flights are analyzed.

U.S. Air Force T&E Days 2010, 2010

The Benefield Anechoic Facility (BAF), located at Edwards Air Force Base, is the world"s largest ... more The Benefield Anechoic Facility (BAF), located at Edwards Air Force Base, is the world"s largest anechoic chamber. The BAF provides a test environment that has a number of uses: Evaluation of radar warning receiver (RWR) systems. The BAF can generate both free-space and direct-inject signals to test RWR systems, provide real-time environment monitoring, and can record both the simulated signal environment and system under test (SUT) emissions. Evaluation of defensive avionics system testing: communication, navigation, and identification friend or foe (IFF) testing (CNI). The BAF can simulate a wide variety of signals in the IFF arena. Measure antenna patterns. The BAF can measure antenna patterns of both installed and uninstalled systems. Perform electromagnetic interference / electromagnetic compatibility (EMI/EMC) testing. Approved for Public Release: PA# AFFTC-PA-10013 evaluate the test set up before the SUT and BAF facilities are brought into play. incoming receiver signal magnitude as a function of location.

Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Controls, Diagnostics and Instrumentation, 2012

2008 U.S. Air Force T&E Days, 2008