共查询到20条相似文献,搜索用时 187 毫秒
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在系统失效原因被屏蔽的情形下,讨论三部件串联系统中部件可靠性指标的Bayes估计问题.当部件寿命服从指数分布时,分别在平方损失和LINEX损失下得到了部件未知参数、可靠度函数和失效率函数的Bayes估计.最后通过数值模拟对估计结果进行了分析. 相似文献
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线性回归模型系数岭估计的改进研究 总被引:15,自引:0,他引:15
对作者提出的c-k型估计,进行了进一步的研究.证明利用Stein式压缩技术可以改进岭估计(在均方误差意义下);同时给出了参数的最优值满足的条件.证明了c-k型估计的可容许性.文中的方法为病态线性回归模型系数的有偏估计提供了改进的技术途径. 相似文献
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Bayes估计法是可靠性评估中应用最为广泛的方法之一,指数分布的Bayes验前概率密度函数中的重要参数主要依靠Reformulation法和Box-Tiao法确定,具有较强的主观经验性。基于Beyes估计的基本思想,以试验数据为依据,利用第二类极大似然估计法(ML-Ⅱ估计法)确定Bayes方法中的相关参数,避免了参数确定的主观性。实例表明结果合理,方法客观、可行。 相似文献
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胡庆军 《国防科技大学学报》1997,19(2):107-113
对于线性模型Y=XC+ε,E(ε)=0,Cov(ε,ε)=σ2I,在先验信息(E(C)=0,Cov(C,C)=σ20I)下,本文给出主成分个数的一种更合理取法,并提出了一种改进的主成分估计。文中证明了该估计是可容许估计,且在“平均”均方误差意义下,优于最小二乘估计,亦优于主成分估计 相似文献
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张金槐 《国防科技大学学报》1993,15(4):1-9
本文研究再入飞行器的落点准确度(系统性偏差)的检验和估计方法。首先,文中引入了准确度的容许限的概念,在此基础上给出了Bayes验后加权概率比检验方法。关于落点系统偏差的估计,讨论了Bayes估计方法及带有约束的Bayes估计方法。文中注意了充分运用试验前的信息,以便使落点系统偏差的评估能在小子样场合下进行。 相似文献
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Nancy R. Mann 《海军后勤学研究》1977,24(1):187-196
An approximation suggested in Mann, Schafer and Singpurwalla [18] for obtaining small-sample tolerance bounds based on possibly censored two-parameter Weibull and lognormal samples is investigated. The tolerance bounds obtained are those that effectively make most efficient use of sample data. Values based on the approximation are compared with some available exact values and shown to be in surprisingly good agreement, even in certain cases in which sample sizes are very small or censoring is extensive. Ranges over which error in the approximation is less than about 1 or 2 percent are determined. The investigation of the precision of the approximation extends results of Lawless [8], who considered large-sample maximum-likelihood estimates of parameters as the basis for approximate 95 percent Weibull tolerance bounds obtained by the general approach described in [18]. For Weibull (or extreme-value) data the approximation is particularly useful when sample sizes are moderately large (more than 25), but not large enough (well over 100 for severely censored data) for asymptotic normality of estimators to apply. For such cases simplified efficient linear estimates or maximum-likelihood estimates may be used to obtain the approximate tolerance bounds. For lognormal censored data, best linear unbiased estimates may be used, or any efficient unbiased estimators for which variances and covariances are known as functions of the square of the distribution variance. 相似文献
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极坐标下雷达多目标跟踪及其实现 总被引:1,自引:0,他引:1
王云峰 《军械工程学院学报》2000,12(2):32-35
导出极坐标下雷达多目标跟踪的非线性滤波方程和预测方程 ,获得了稳定和渐近无偏估计 ;采用最优配对法进行点迹与航迹相关 ,避免相关模糊 ;利用记分法进行航迹质量管理 ,并在计算机上实现了多目标跟踪数据处理 相似文献
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王胜兵 《海军工程大学学报》1991,(4)
本文引入带权的 Sobolev 空间,讨论了奇型线性问题:(?)((?)u)/((?)t)-1/x~(?)(x~aa(x)u′)′=f(t,x) (x,t)∈1×J(?)/((?)x)u(t,0)=u(t,1)=0 t∈Ju(0,x)=φ(x) x∈I式中 I=(0,1),J=[0,T],0<α<3的有限元方法,并在适当条件下,给出了最佳估计:‖u_(?)-u‖_(0,2,a)≤ch~2{‖φ‖_(2,2,a)+[integral 0 to t (‖u‖~2_(2,2,a)+‖u_(?)‖~2_(2,2,a)dt]~(1/2)}‖u_(?)-u‖_(1,2,a)≤ch~2{‖φ‖_(2,2,a)+[integral 0 to t (‖u‖~2_(2,2,a)+‖u_(?)‖~2_(2,2,a)dt]~(1/2)} 相似文献
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This article investigates the demand for military expenditure for a sample of key Asia-Pacific countries. Spatial panel demand estimates are presented for three joined spatial units using a fixed-coefficient spatial lag model based on a two-step efficient GMM estimator. Spatial autoregression estimates are next presented for 1991–2015, founded on alternative kinds of country connectivities, such as contiguity, inverse distance, discrete distance, and power-projection considerations. Finally, 11 select countries’ demands for defense equations are estimated using seemingly unrelated regressions. From alternative perspectives, these estimated models indicate how Asia-Pacific countries respond to the defense spending of other countries. In the spatial runs, free riding is prevalent despite the growing military might of China, which apparently is not generally viewed as a threat. For the sample period, the projection of Chinese or American power is a relevant spatial factor. The main threat is reflected in non-U.S. allies’ reaction to U.S. allies’ defense spending during 1991–2015 and to Chinese defense spending after 2002. 相似文献
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In an ordered sample from a given population, a few of the consecutive observations from somewhere in the middle may be missing Further, we may be constrained to use a few, and not all, of the remaining observations for purposes of estimation of population parameters. In this paper, such a situation is considered for the double exponential distribution and best linear unbiased estimates are obtained for its parameters, based on a choice of an optimum set of order statistics when the number of observations in the set are prefixed. 相似文献
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系统辨识方法在微型飞行器建模中的应用 总被引:4,自引:0,他引:4
为对微型飞行器的飞行进行控制,需要建立其动力学模型。讨论了微型飞行器模型的系统辨识方法,设计了实验方法与采集装置,在数据处理、模型结构选择、模型评价等方面进行了探讨。简要介绍了输入输出端存在噪声时系统的线性最小二乘无偏辨识方法原理,最后给出了微型飞行器的纵向通道的仿真算例,结果表明,运用这种方法对微型飞行器进行建模是准确而有效的。 相似文献
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M. Mazumdar 《海军后勤学研究》1969,16(2):199-206
This paper obtains the uniformly minimum variance unbiased estimates of two indices of performance of a system which alternates between two states “up” or “down” in accordance with a Markov process. The two indices are (1) operational readiness, which measures the probability that the system will be up when needed; and (2) operational reliability, which measures the probability that the system will be up during the entire time of need. For the purpose of obtaining these estimates, two types of observations are considered: (a) those which reveal only the state of system at isolated time-points, and (b) those which continuously record the duration of the “up” and “down” times of the system. 相似文献
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Consider an auction in which increasing bids are made in sequence on an object whose value θ is known to each bidder. Suppose n bids are received, and the distribution of each bid is conditionally uniform. More specifically, suppose the first bid X1 is uniformly distributed on [0, θ], and the ith bid is uniformly distributed on [Xi?1, θ] for i = 2, …?, n. A scenario in which this auction model is appropriate is described. We assume that the value θ is un known to the statistician and must be esimated from the sample X1, X2, …?, Xn. The best linear unbiased estimate of θ is derived. The invariance of the estimation problem under scale transformations in noted, and the best invariant estimation problem under scale transformations is noted, and the best invariant estimate of θ under loss L(θ, a) = [(a/θ) ? 1]2 is derived. It is shown that this best invariant estimate has uniformly smaller mean-squared error than the best linear unbiased estimate, and the ratio of the mean-squared errors is estimated from simulation experiments. A Bayesian formulation of the estimation problem is also considered, and a class of Bayes estimates is explicitly derived. 相似文献
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安晓伟 《中国人民武装警察部队学院学报》2009,25(12):88-89
研究了一类具有不同类型反应项的半非线性抛物型方程组初边值问题,这类模型主要描述两种物质燃烧过程中的热传递规律。通过运用古典计算技巧和偏微分方程的定性分析手法,得到了这类半非线性抛物型方程组初边值问题解的爆破速率估计。 相似文献