7,962 research outputs found
Design, construction and testing of the Communications Technology Satellite protection against spacecraft charging
Detailed discussions are presented of the measures taken on the Communications Technology Satellite (CTS or Hermes) which provide protection against the effects of spacecraft charging. These measures include: a comprehensive grounding philosophy and implementation; provision of command and data line transmitters and receivers for transient noise immunity; and a fairly restrictive EMI specification. Ground tests were made on materials and the impact of these tests on the CTS spacecraft is described. Hermes, launched on 17 January 1976 on a 2914 Delta vehicle, has successfully completed 10 months of operations. Anomalies observed are being assessed in relation to spacecraft charging, but no definite correlations have yet been established. A list of conclusions with regard to the CTS experience is given and recommendations for future spacecraft are also listed
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Using discrete event simulation (DES) to manage theatre operations in healthcare: An audit-based case study
This paper discusses the application of Discrete Event Simulation (DES) in modelling the complex relationship between patient types, case-mix and operating theatre allocation in a large National Health Service (NHS) Trust in London. The simulation model that was constructed described the main features of nine theatres, focusing on operational processes and patient throughput times. The model was used to test three scenarios of case-mix and to demonstrate the potential of using simulation modelling as a cost effective method for understanding the issues of healthcare operations management and the role of simulation techniques in problem solving. The results indicated that removing all day cases will reduce patient throughput by 23.3% and the utilization of the orthopaedic theatre in particular by 6.5%. This represents a case example of how DES can be used by healthcare managers to inform decision making
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A review of historical developments of quality assessment in industry and healthcare
Purpose: This study reviewed the literature on the historical development of quality assessment methods in industry and in healthcare. A comparative analysis of quality methods in industry and healthcare was conducted to examine the gap between methods in the two sectors. An attempt was then made to examine the latest approaches to quality assessment in healthcare and finally a proposal has been offered for a more effective approach to tackling the problem of quality in healthcare.
Design/methodology/approach:
Firstly, a review of the evolution of quality assessment in industry and healthcare was conducted. This was based on books written by prominent experts in the field of quality. secondly, a study of the current approaches in healthcare was undertaken. Publications from varied sources were selected and reviewed. The literature consulted includes worldwide operations research and healthcare sources including dissertations, the internet and reference lists of relevant articles.
The journal papers and conference proceedings were selected according to the following criteria: Objective: the study must be aimed at measuring or improving quality both. It could also be aimed at developing new ways of measuring the quality of health care; Method: observational studies, experimental trials or systematic reviews; Setting: study should be in a hospital setting and not narrowed to quality of clinical cares.
Findings: This study showed that the concept of quality management and its control in healthcare is not as advanced as it is in industry. Moreover, it seemed that most researchers, who set out to assess quality of care in one way or the other, have had differing views of quality and the factors that contribute to its assessment. It was also deduced that the way forward in healthcare quality is the development of systems that give staff ownership and pride in a way that is akin to the era of the craftsmen
Design and analysis considerations for deployment mechanisms in a space environment
On the second flight of the INTELSAT V spacecraft the time required for successful deployment of the north solar array was longer than originally predicted. The south solar array deployed as predicted. As a result of the difference in deployment times a series of experiments was conducted to locate the cause of the difference. Deployment rate sensitivity to hinge friction and temperature levels was investigated. A digital computer simulation of the deployment was created to evaluate the effects of parameter changes on deployment. Hinge design was optimized for nominal solar array deployment time for future INTELSAT V satellites. The nominal deployment times of both solar arrays on the third flight of INTELSAT V confirms the validity of the simulation and design optimization
Multiple wavelength light collimator and monitor
An optical system for receiving and collimating light and for transporting and processing light received in each of N wavelength ranges, including near-ultraviolet, visible, near-infrared and mid-infrared wavelengths, to determine a fraction of light received, and associated dark current, in each wavelength range in each of a sequence of time intervals
DEDUCTIVE, INDUCTIVE . . . AND A THIRD WAY
Building on two previously published papers, âFailure to Communicateâ and âNecessities and Capacities,â (Journal of Modern Ministry, Winter 2011 and Spring 2011) this paper furthers the argument that print-age preaching is not well-suited for the digital age. The paper examines the âthird wayâ options of Calvin Miller and Paul Wilson which seek to combine the best of expository preaching and narrative preaching. This paper does not assert there are no effective âprint-age preachersâ in pulpits today, nor does it suggest there are no âprint-age listenersâ in congregations. Rather, the point is that the significant shifts in culture, communication, and technology leave us with the unavoidable conclusion that the âthe necessities and capacities of the hearersâ have changed, particularly from the mid twentieth-century until the present. This paper identifies deductive preaching as classic, linear, print-age âexpository preachingâ and discusses the alternatives offered by the âNew Homiletic,â particularly the inductive approaches of Fred Craddock and Gene Lowry. The paper concludes the âthird wayâ options of Calvin Miller and Paul Wilson are uniquely helpful in our twenty-first century, North American context
Reconstructing 3D x-ray CT images of polymer gel dosimeters using the zero-scan method
In this study x-ray CT has been used to produce a 3D image of an irradiated PAGAT gel sample, with noise-reduction achieved using the âzero-scanâ method. The gel was repeatedly CT scanned and a linear fit to the varying Hounsfield unit of each pixel in the 3D volume was evaluated across the repeated scans, allowing a zero-scan extrapolation of the image to be obtained. To minimise heating of the CT scannerâs x-ray tube, this study used a large slice thickness (1 cm), to provide image slices across the irradiated region of the gel, and a relatively small number of CT scans (63), to extrapolate the zero-scan image. The resulting set of transverse images shows reduced noise compared to images from the initial CT scan of the gel, without being degraded by the additional radiation dose delivered to the gel during the repeated scanning. The full, 3D image of the gel has a low spatial resolution in the longitudinal direction, due to the selected scan parameters. Nonetheless, important features of the dose distribution are apparent in the 3D x-ray CT scan of the gel. The results of this study demonstrate that the zero-scan extrapolation method can be applied to the reconstruction of multiple x-ray CT slices, to provide useful 2D and 3D images of irradiated dosimetry gels
Investigation and study of a multi-aperture antenna system final report, 1 jan. - 1 apr. 1964
Multiple aperture adaptive antenna system for telemetry reception from remote space vehicle
Application of One-, Three-, and Seven-Day Forecasts During Early Onset on the COVID-19 Epidemic Dataset Using Moving Average, Autoregressive, Autoregressive Moving Average, Autoregressive Integrated Moving Average, and NaĂŻve Forecasting Methods
The coronavirus disease 2019 (COVID-19) spread rapidly across the world since its appearance in December 2019. This data set creates one-, three-, and seven-day forecasts of the COVID-19 pandemic\u27s cumulative case counts at the county, health district, and state geographic levels for the state of Virginia. Forecasts are created over the first 46 days of reported COVID-19 cases using the cumulative case count data provided by The New York Times as of April 22, 2020. From this historical data, one-, three-, seven, and all-days prior to the forecast start date are used to generate the forecasts. Forecasts are created using: (1) a NaĂŻve approach; (2) Holt-Winters exponential smoothing (HW); (3) growth rate (Growth); (4) moving average (MA); (5) autoregressive (AR); (6) autoregressive moving average (ARMA); and (7) autoregressive integrated moving average (ARIMA). Median Absolute Error (MdAE) and Median Absolute Percentage Error (MdAPE) metrics are created with each forecast to evaluate the forecast with respect to existing historical data. These error metrics are aggregated to provide a means for assessing which combination of forecast method, forecast length, and lookback length are best fits, based on lowest aggregated error at each geographic level. The data set is comprised of an R-Project file, four R source code files, all 1,329,404 generated short-range forecasts, MdAE and MdAPE error metric data for each forecast, copies of the input files, and the generated comparison tables. All code and data files are provided to provide transparency and facilitate replicability and reproducibility. This package opens directly in RStudio through the R Project file. The R Project file removes the need to set path locations for the folders contained within the data set to simplify setup requirements. This data set provides two avenues for reproducing results: 1) Use the provided code to generate the forecasts from scratch and then run the analyses; or 2) Load the saved forecast data and run the analyses on the stored data. Code annotations provide the instructions needed to accomplish both routes. This data can be used to generate the same set of forecasts and error metrics for any US state by altering the state parameter within the source code. Users can also generate health district forecasts for any other state, by providing a file which maps each county within a state to its respective health-district. The source code can be connected to the most up-to-date version of The New York Times COVID-19 dataset allows for the generation of forecasts up to the most recently reported data to facilitate near real-time forecasting
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