GEOS-3 C-Band radar investigations

The absolute accuracy of instrumentation radar systems, refined methods of calibrating these systems, and the techniques employed in processing the associated data. A world-wide network of C-Band instrumentation radars augmented by lasers and other tracking instrumentation systems were used. The NASA WFC AN/FPQ-6 instrumentation radar and the AN/FPS-16 instrumentation radar also located at NASA WFC were the primary instruments used in the accuracy and calibration evaluations. The results achieved at WFC were then disseminated to other Ranges where they were verified, augmented and used as part of routine operations

Head impact exposure in junior and adult Australian football players

Tis study measured and compared the frequency, magnitude, and distribution of head impacts sustained by junior and adult Australian football players, respectively, and between player positions over a season of games. Twelve junior and twelve adult players were tracked using a skin-mounted impact sensor. Head impact exposure, including frequency, magnitude, and location of impacts, was quantifed using previously established methods. Over the collection period, there were no signifcant diferences in the impact frequency between junior and adult players. However, there was a signifcant increase in the frequency of head impacts for midfelders in both grades once we accounted for player position. A comparable amount of head impacts in both junior and adult players has implications for Australian football regarding player safety and medical coverage as younger players sustained similar impact levels as adult players. Te other implication of a higher impact profle within midfelders is that, by targeting education and prevention strategies, a decrease in the incidence of sports-related concussion may result

Ride quality meter

A ride quality meter is disclosed that automatically transforms vibration and noise measurements into a single number index of passenger discomfort. The noise measurements are converted into a noise discomfort value. The vibrations are converted into single axis discomfort values which are then converted into a combined axis discomfort value. The combined axis discomfort value is corrected for time duration and then summed with the noise discomfort value to obtain a total discomfort value

Vibration simulator studies for the development of passenger ride comfort criteria

A test program to determine the total discomfort associated with vehicle vibration is described. The program utilizes a three-degree-of-freedom vibration simulator to determine the effects of multifrequency and multiaxis vibration inputs. The approach to multifrequency vibration includes a separate consideration of the discomfort associated with each frequency component or band of the total spectrum and a subsequent empirical weighting of the discomfort components of these frequency bands when in various random combinations. The results are in the form of equal discomfort curves that specify the discomfort associated with discrete frequencies between 1 and 30 Hz and different acceleration levels. These results provide detailed information of the human discomfort response to increases in acceleration level for each frequency investigated. More importantly, the results provide a method for adding the discomfort associated with separate frequencies to give a total typification of the discomfort of a random spectrum of vibration

Experimental studies for determining human discomfort response to vertical sinusoidal vibration

A study was conducted to investigate several problems related to methodology and design of experiments to obtain human comfort response to vertical sinusoidal vibration. Specifically, the studies were directed to the determination of (1) the adequacy of frequency averaging of vibration data to obtain discomfort predictors, (2) the effect of practice on subject ratings, (3) the effect of the demographic factors of age, sex, and weight, and (4) the relative importance of seat and floor vibrations in the determination of measurement and criteria specification location. Results indicate that accurate prediction of discomfort requires knowledge of both the acceleration level and frequency content of the vibration stimuli. More importantly, the prediction of discomfort was shown to be equally good based upon either floor accelerations or seat accelerations. Furthermore, it was demonstrated that the discomfort levels in different seats resulting from similar vibratory imputs were equal. Therefore, it was recommended that criteria specifications and acceleration measurements be made at the floor location. The results also indicated that practice did not systematically influence discomfort responses nor did the demographic factors of age, weight, and sex contribute to the discomfort response variation

C-band radar pulse Doppler error: Its discovery, modeling, and elimination

The discovery of a C Band radar pulse Doppler error is discussed and use of the GEOS 3 satellite's coherent transponder to isolate the error source is described. An analysis of the pulse Doppler tracking loop is presented and a mathematical model for the error was developed. Error correction techniques were developed and are described including implementation details

A study of possible sea state information in the sample and hold gate statistics for the GEOS-3 satellite altimeter

The statistical variations in the sample gate outputs of the GEOS-3 satellite altimeter were studied for possible sea state information. After examination of a large number of statistical characteristics of the altimeter waveforms, it was found that the best sea predictor for H-1/3 in the range of 0 to 3 meters was the 75th percentile of sample and hold gate number 11

An investigation of ride quality rating scales

An experimental investigation was conducted for the combined purposes of determining the relative merits of various category scales for the prediction of human discomfort response to vibration and for determining the mathematical relationships whereby subjective data are transformed from one scale to other scales. There were 16 category scales analyzed representing various parametric combinations of polarity, that is, unipolar and bipolar, scale type, and number of scalar points. Results indicated that unipolar continuous-type scales containing either seven or nine scalar points provide the greatest reliability and discriminability. Transformations of subjective data between category scales were found to be feasible with unipolar scales of a larger number of scalar points providing the greatest accuracy of transformation. The results contain coefficients for transformation of subjective data between the category scales investigated. A result of particular interest was that the comfort half of a bipolar scale was seldom used by subjects to describe their subjective reaction to vibration

Interventions to Improve Adolescent Vaccination What May Work and What Still Needs to Be Tested

This article is being published concurrently in the American Journal of Preventive Medicine and Vaccine. The articles are identical except for stylistic changes in keeping with each journalʼs style. Either of these versions may be used in citing this article. See: Dempsey, A. F., & Zimet, G. D. (2015). Interventions to Improve Adolescent Vaccination: What May Work and What Still Needs to Be Tested. Vaccine, 33, Supplement 4, D106–D113. http://doi.org/10.1016/j.vaccine.2015.09.032Since the development of the “adolescent platform” of vaccination in 1997, hundreds of studies have been conducted, identifying barriers to and facilitators of adolescent vaccination. More recent research has focused on developing and evaluating interventions to increase uptake of adolescent vaccines. This review describes a selection of recent intervention studies for increasing adolescent vaccination, divided into three categories: those with promising results that may warrant more widespread implementation, those with mixed results requiring more research, and those with proven effectiveness in other domains that have not yet been tested with regard to adolescent vaccination