In this work, the optimal control of an harmonic oscillator is considered. The external field is assumed to be weak and hence is represented by only dipole interaction. The dipole function is taken as a second degree ...
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The main purpose of this work is to obtain the general structure of a product type of multivariate function when the values of the function are given randomly at the nodes of a hyperprism. When the dimensionality of m...
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Background: Emergency department (ED) based syndromic surveillance systems identify abnormally high visit rates that may be an early signal of a bioterrorist attack. For example, an anthrax outbreak might first be det...
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Background: Emergency department (ED) based syndromic surveillance systems identify abnormally high visit rates that may be an early signal of a bioterrorist attack. For example, an anthrax outbreak might first be detectable as an unusual increase in the number of patients reporting to the ED with respiratory symptoms. Reliably identifying these abnormal visit patterns requires a good understanding of the normal patterns of healthcare usage. Unfortunately, systematic methods for determining the expected number of (ED) visits on a particular day have not yet been well established. We present here a generalized methodology for developing models of expected ED visit rates. Methods: Using time-series methods, we developed robust models of ED utilization for the purpose of defining expected visit rates. The models were based on nearly a decade of historical data at a major metropolitan academic, tertiary care pediatric emergency department. The historical data were fit using trimmed-mean seasonal models, and additional models were fit with autoregressive integrated moving average (ARIMA) residuals to account for recent trends in the data. The detection capabilities of the model were tested with simulated outbreaks. Results: Models were built both for overall visits and for respiratory-related visits, classified according to the chief complaint recorded at the beginning of each visit. The mean absolute percentage error of the ARIMA models was 9.37% for overall visits and 27.54% for respiratory visits. A simple detection system based on the ARIMA model of overall visits was able to detect 7-day-long simulated outbreaks of 30 visits per day with 100% sensitivity and 97% specificity. Sensitivity decreased with outbreak size, dropping to 94% for outbreaks of 20 visits per day, and 57% for 10 visits per day, all while maintaining a 97% benchmark specificity. Conclusions: Time series methods applied to historical ED utilization data are an important tool for syndromic surveilla
Introduction: Transport times, such as time of call, are an essential part of the patient record. The purpose of this study was to validate a previously proposed minimum data set of time-related terms. Methods: A stra...
Introduction: Transport times, such as time of call, are an essential part of the patient record. The purpose of this study was to validate a previously proposed minimum data set of time-related terms. Methods: A stratified sample of 508 nurses, physicians, paramedics, pilots, and communication specialists was selected to participate in the validation survey. Subjects indicated their agreement/disagreement with the proposed terms and their definitions on a scale of 1 (low) to 3 (high). In addition, subjects indicated whether they currently collect the data elements or could do so easily. Finally, subjects said whether they were willing to release aggregate data for benchmarking purposes. Results: One-hundred-eighteen subjects (23.2%) responded to the survey with usable data. Agreement to include the terms (level 3) ranged from 71.2% to 95.8%. Agreement with the proposed definition ranged from 72.9% to 95.8%. Seventy-eight of the respondents were willing to release all the data elements. Conclusion: Fourteen of the 19 terms are recommended for inclusion in a minimum data set for rotor-wing transport. Most persons expressed willingness to release data for benchmarking efforts.
Due to a widely use of XML language in various application domains, a well-established mechanism for the definition and enforcement of security controls on specific accesses to XML documents is demanded, in order to e...
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A parallel implementation for linear set of equations of the form Ax = b is presented in this paper. In this implementation, instead of the traditional direct solution of Ax = b, conjugate gradient method is used. The...
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A parallel implementation for linear set of equations of the form Ax = b is presented in this paper. In this implementation, instead of the traditional direct solution of Ax = b, conjugate gradient method is used. The conjugate gradient method is accelerated with an approximate inverse matrix preconditioner obtained from a linear combination of matrix-valued Chebyshev polynomials. This implementation is tested on a Sun SMP machine. Since conjugate gradient method and preconditioner contain mainly matrix-vector and matrix-matrix multiplications, convincing results are obtained in terms of both speed and scalability.
A parallel implementation for linear set of equations of the form Ax = b is presented in this paper. In this implementation, instead of the traditional direct solution of Ax = b, conjugate gradient method is used. The...
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A parallel implementation for linear set of equations of the form Ax = b is presented in this paper. In this implementation, instead of the traditional direct solution of Ax = b, conjugate gradient method is used. The conjugate gradient method is accelerated with an approximate inverse matrix preconditioner obtained from a linear combination of matrix-valued Chebyshev polynomials. This implementation is tested on a Sun SMP machine. Since conjugate gradient method and preconditioner contain mainly matrix-vector and matrix-matrix multiplications, convincing results are obtained in terms of both speed and scalability.
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