Engineering topics
Publications and source records attributed to Sanders, W..
In this paper, we present a performability study that analyzes the guarded operation duration for onboard software upgrading.
In order to accomplish dependable onboard evolution, we develop a methodology which is called guarded software upgrading (GSU).
The evolvable avionics systems such as the X2000 at NASA/JPL are able to have software upgrades during a long-life mission for dependability, performance and functionality improvement.
Soft-X-ray maps in the B, C, and M (130-188, 160-284, and 440-1100-eV) bands, based on sounding-rocket observations obtained in the Wisconsin all-sky survey over a 10-yr period are presented and discussed. The B and C band maps are found to be similar, and comparison with the H I column densities of Cleary et al. (1979) shows an anticorrelation of B and C emission with neutral gas, implying hot-interstellar-gas emission from within 100 pc of the sun. The M-band pattern is different, and may be due to extragalactic high-energy diffuse emission and/or M dwarfs, although extragalactic sources are not specifically required to explain the data.
The pulse-contour method for determining stroke volume has been employed as a continuous rapid method of monitoring the cardiovascular status of patients. Twenty-one patients with ischemic heart disease and 21 patients with mitral valve disease were subjected to a variety of hemodynamic interventions. The pulse-contour estimations, using three different formulas derived by Warner, Kouchoukos, and Herd, were compared with indicator-dilution outputs. A comparison of the results of the two methods for determining stroke volume yielded correlation coefficients ranging from 0.59 to 0.84. The better performing Warner formula yielded a coefficient of variation of about 20%. The type of hemodynamic interventions employed did not significantly affect the results using the pulse-contour method. Although the correlation of the pulse-contour and indicator-dilution stroke volumes is high, the coefficient of variation is such that small changes in stroke volume cannot be accurately assessed by the pulse-contour method. However, the simplicity and rapidity of this method compared to determination of cardiac output by Fick or indicator-dilution methods makes it a potentially useful adjunct for monitoring critically ill patients.