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Andrew G. Sparks Hsi-Han Yeh Siva S. Banda 《Optimal control applications & methods.》1990,11(4):307-325
This paper introduces a design methodology for a dynamic compensator that simultaneously minimizes the upper bound of a quadratic performance index and the H∞-norm of a disturbance transfer function matrix of a multiple-input/multiple-output system whose model contains parameter uncertainty in the state and input matrices. The real parameter uncertainty is modelled as additional measurement outputs and as additional weights on the existing noise inputs and measurement outputs of the system. The compensator equations are derived by taking the dual of a system with parameter variation in the state and output matrices, for which the compensator equations have previously been derived, and then taking the dual of the compensator equations. An algorithm for applying this theory is given and an example is shown. 相似文献
3.
用44例原发性高血压(EH)患者及15例健康人对照组(N)的平衡法心血池显像(MGBP)心功能参数,对比分析了EH组多普勒超声心动图(UCG)及心机械图(MCG)的心脏检测指标.结果示,MGBP检测中 EH 组的左室高峰充盈率(PFR)、右室射血分数(RVEF)、局部射血分数_4(EF_4)及局部轴缩短率_4(RS_4)明显低于对照组(P<0.05~0.01).反映左室舒张功能的PFR与E/A峰比值(UCG)之间呈正相关(r=0.44,P<0.05),PFR与a/Eo(MCG)之间呈负相关(r=-0.87 P<0.01),PFR与左房内径(UCG)之间呈负相关(r=-0.48 P<0.05),反映左室间隔部位改变的EF_4,RS_4与室间隔厚度(UCG)均呈负相关(r=-0.3 P<0.05,;γ=-0.47 P<0.05). 相似文献
4.
Eigenstructure assignment using output feedback is reformulated using an auxiliary principle of minimization of control effort. In the general eigenstructure assignment procedure, the feedback gain matrix is uniquely determined for a set of explicitly specified desired eigenvalues and eigenvectors. However, for the controller design proposed in this paper, only the most necessary constraints are imposed on the desired eigenvalues and eigenvectors, and the unspecified model parameters of the closed-loop system are determined by minimizing the control effort. Numerical examples are presented for comparison of the proposed method with standard eigenstructure assignment methods, and an experimental example gives an insight into the feasibility of the proposed control algorithm with application to the vibration control of flexible structures undergoing forced vibration. 相似文献
5.
目的探讨50岁以上正常人左室舒张期脉冲多普勒频谱的参数变化情况。方法选择一年半时间内受检的所有50岁以上正常人475例,按每10岁为一组分4组进行分析。受检者取左侧卧位,常规显示心尖四腔心切面,取样容积置于二尖瓣尖,使声束与二尖瓣血流方向夹角<15°,以连续三个心动周期的平均值分别测量E峰、A峰、E/A及E峰减速时间并统计。结果发现E峰高于正常值低限的例数、平均E峰血流速度以及E/A均随着年龄的增加而下降,E峰减速时间则随着增龄而增加。结论左室舒张期血流频谱的所有参数与年龄有显著的相关性,明显随着增龄而变化,并且有其规律性。 相似文献
6.
A new one-step computational procedure is presented for estimating the parameters of the nonlinear three-element windkessel
model of the arterial system incorporating a pressure-dependent compliance. The data required are pulsatile aortic pressure
and flow. The basic assumptions are a steadystate periodic regime and a purely elastic compliant element. By stating two conditions,
zero mean flow and zero mean power in the compliant element, peripheral and characteristic resistances are determined through
simple closed form formulas as functions of mean values of the square of aortic pressure, the square of aortic flow, and the
product of aortic pressure with aortic flow. The pressure across as well as the flow through the compliant element can be
then obtained so allowing the calculation of volume variation and compliance as functions of pressure. The feasibility of
this method is studied by applying it to both simulated and experimental data relative to different circulatory conditions
and comparing the results with those obtained by an iterative parameter optimization algorithm and with the actual values
when available. The conclusion is that the proposed method appears to be effective in identifying the three-element windkessel
even in the case of nonlinear compliance. 相似文献
7.
目的 :介绍并分析适用于医学动态监测数据的稳健参数估计方法。方法 :结合分布假设和稳健统计给出了参数估计方法。首次提出了一种迭代求取形状参数稳健估计的算法。结果 :该方法对医学动态监测中某种生理量异常所占百分比值统计量的参数估计优于临床普遍采用的方法。结论 :通过对分布拟合、估计优效性和可实现性、估计稳健性等的理论分析和模拟实验表明该方法是一种高效、可靠的稳健参数估计方法 相似文献
8.
The constant-phase model is increasingly used to fit low-frequency respiratory input impedance (Zrs), highlighting the need for a better understanding of the use of the model. Of particular interest is the extent to which Zrs would be affected by changes in parameters of the model, and conversely, how reliable are parameters estimated from model fits to the measured Zrs. We performed sensitivity analysis on respiratory data from 6 adult mice, at functional residual capacity (FRC), total lung capacity (TLC), and during bronchoconstriction, obtained using a 1-25 Hz oscillatory signal. The partial derivatives of Zrs with respect to each parameter were first examined. The limits of the 95% confidence intervals, 2-dimensional pairwise and p-dimensional joint confidence regions were then calculated. It was found that airway resistance was better estimated at FRC, as determined by the confidence region limits, whereas tissue damping and elastance were better estimated at TLC. Airway inertance was poorly estimated at this frequency range, as expected. During methacholine-evoked pulmonary constriction, there was an increase in the uncertainty of airway resistance and tissue damping, but this can be compensated for by using the relative (weighted residuals) in preference over the absolute (unweighted residuals) fitting criterion. These results are consistent with experimental observation and physiological understanding. 相似文献
9.
目的 探讨血小板参数在急性水肿型胰腺炎 (AEP)和出血坏死性胰腺炎 (AHNP)中的变化特点及生长抑素 (SS)对其影响。方法 应用血细胞自动分析仪检测AEP和AHNP病人不同时期血小板计数 (PLT) ,平均血小板体积 (MPV)和血小板分布宽度 (PDW )。结果 AEP患者血小板参数无明显变化 ,1周后 ,PLT无明显升高 ,MPV和PDW有显著性升高 (P <0 .0 5 ) ;常规治疗后 ,对血小板参数无影响 ;SS治疗后 ,MPV和PDW有显著性升高 (P <0 .0 5 )。而AHNP患者PLT显著降低 (P <0 .0 5 ) ,MPV和PDW有显著性升高 (P <0 .0 5 ) ,1周后PLT显著性升高 (P <0 .0 5 ) ,但MPV和PDW无明显降低 ;常规治疗后 ,PLT升高 ,MPV、PDW均降低 (P <0 .0 5 ) ;SS治疗后PLT显著性升高 (P <0 .0 5 ) ,MPV、PDW无明显变化。结论 AEP与AHNP患者血小板参数的变化有明显不同 ,可反映病情变化。SS治疗后 ,对PLT无影响 ,但可增加血小板的活性 ,对AHNP患者有一定的治疗和预防作用 相似文献
10.
J. Dahn M. Oster A. Möltner C. Wöhrle A. Rätzer-Frey K. van Ackern R. Hölzl W. Segiet 《Der Anaesthesist》1999,48(6):379-386
Objective: The aim of the present study was to show the influence of the parameters of gas exchange (arterial oxygen pressure paO2, arterial oxygen saturation SatO2) and haemodynamics (arterial systolic and mean blood pressure RRs and MAP) on the restitution of cognitive functions in geriatric patients scheduled for elective hip arthroplasty. Methods: A total of 30 patients (70 years, ASA II) were randomized to be operated either in regional anaesthesia (n=15) or general anaesthesia (n=15). PaO2 (by capillary blood gas analysis), RRs and MAP (by oscillometry) were measured 15 and 90 minutes after arrival in the recovery unit (t1 and t2), 24 and 72 hours postoperatively (t3 and t4), and cognitive functions were tested. Intraoperatively, throughout the day and the first night after surgery we measured satO2 by continous pulse oximetry. We recorded MAP and RRs by oscillometry every 3 minutes during the operation and every15 minutes for the rest of that day and night. Results: The parameters of gas exchange and haemodynamics did not differ among the groups. PaO2 was significantly reduced in both groups compared to baseline 24 hours postoperatively (t3) and remained low until 72 hours postoperatively (t4). Nearly all cognitive functions were significantly reduced in both groups compared to baseline 15 and 90 minutes after arrival in the recovery unit (t1 and t2), but recovered on the first postoperative day (t3). Both groups kept deficits in verbal memory and reading capacity up to the third postoperative day (t4). There was no correlation between the physiological parameters and the restitution of the tested cognitive functions. Conclusion: The restitution of cognitive functions during the first three postoperative days in geriatric patients scheduled for elective hip surgery does not depend on the anaesthetic technique. According to our results regional anaesthesia does not show any advantage for geriatric patients undergoing elective hip arthroplasty. 相似文献