共查询到18条相似文献,搜索用时 62 毫秒
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构造了逆高斯分布中变异系数的广义枢轴量,给出了一种参数的区间估计方法,并与MOVOER(method of variance of estimates recovery)和Bootstrap 方法进行比较;给出了多总体下尺度参数两两差的同时置信区间.模拟结果表明:在中、小样本情况下,所给的广义置信区间其覆盖概率接近置信... 相似文献
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加速退化因子的研究 总被引:1,自引:0,他引:1
刘合财 《数学的实践与认识》2010,40(12)
主要讨论了可靠性工程中加速退化失效问题中的加速退化因子,给出了Ⅰ、Ⅱ型加速退化因子的定义,并研究了它们之间的关系、性质及其应用. 相似文献
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研究了随时间发生线性退化和随机振荡导致瞬时退化的系统可靠度及定期维修策略。随机振荡的发生次数服从非时齐泊松过程,每次振荡造成系统的退化量独立同分布。当累积退化量达到阀值时,系统发生故障。为了改善系统工作状态,降低故障风险,每隔T时对系统进行不完全预防维修,维修后故障率函数将发生变化,维修成本与系统的退化程度有关。在NT时,对系统进行完全预防维修,使系统修旧如新。构建了系统的可靠度函数。在单位时间平均利润最大的前提下,提出不完全预防维修间隔T和完全预防维修周期NT的确定方法。分析了模型参数对维修决策的影响。 相似文献
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退化试验是工业统计中一种常用的可靠性分析方法.本文考虑了在破坏性加速退化试验中,应力带有误差的Berkson测量误差模型,推广了最小距离估计在固定个指示变量的情况,并证明了所得估计的相合性和渐近正态性.模拟结果显示本文的估计方法优于不考虑应力误差的最小二乘估计. 相似文献
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本文提出了一个广义线性随机效应模型, 通过综合来自不同储存环境下的同源产品的试验数据信息来评估一类高可靠小样本产品的储存寿命, 并给出了相应的算法. 模拟结果显示了本文提出的模型及方法的合理性和有效性. 相似文献
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讨论了一类步进应力的加速退化试验,在试验假定下,以退化失效分布平均寿命的极大似然估计与其真值的接近程度为标准得到一个精度限制.然后根据试验的过程得到了试验成本函数的一般表达形式.在估计精度的限制之下,最小化成本函数,以此得出试验的最优设计模型.最后,给出了一个数值例子,展示了优化设计的过程. 相似文献
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作业车间调度问题是典型的NP难题,在生产调度领域具有很高的研究价值.一种更为符合实际的作业车间调度问题是加工机器具有学习退化效应,它能够为生产者安排生产计划提供借鉴.为了可以更好的解决具有学习退化效应的作业车间调度问题,本文提出了改进的萤火虫算法(IFA),即在基本的萤火虫算法基础上增加了局部寻优的过程,并融合了布谷鸟算法中生物移动的莱维分布特点.通过MATLAB模拟分析,IFA能够更快速的收敛到JSP的最优解.最后,本文分析了不同学习率与退化效应因子组合对目标函数求解的影响. 相似文献
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In accelerated life tests (ALTs), test units are often tested in multiple test chambers along with different stress conditions. The nonhomogeneity of test chambers precludes the complete randomized experiment and may affect the life‐stress relationship of the test product. The chamber‐to‐chamber variation should be taken into account for ALT planning so as to obtain more accurate test results. In this paper, planning ALTs under a nested experimental design structure with random test chamber effects is studied. First, by a 2‐phase approach, we illustrate to what extent different test chamber assignments to stress conditions may impact the estimation of unknown parameters. Then, D‐optimal test plans with 2 test chambers are considered. To construct the optimal design, we establish the generalized linear mixed model for failure‐time data and apply a quasi‐likelihood method, where test chamber assignments, as well as other decision variables that are required for planning ALTs, are simultaneously determined. 相似文献
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Fiducial inference in the pivotal family of distributions 总被引:11,自引:0,他引:11
XU Xingzhong & LI Guoying Department of Mathematics Beijing Institute of Technology Beijing China Academy of Mathematics Systems Science Chinese Academy of Sciences Beijing China 《中国科学A辑(英文版)》2006,49(3):410-432
In this paper a family, called the pivotal family, of distributions is considered. A pivotal family is determined by a generalized pivotal model. Analytical results show that a great many parametric families of distributions are pivotal. In a pivotal family of distributions a general method of deriving fiducial distributions of parameters is proposed. In the method a fiducial model plays an important role. A fiducial model is a function of a random variable with a known distribution, called the pivotal random element, when the observation of a statistic is given. The method of this paper includes some other methods of deriving fiducial distributions. Specially the first fiducial distribution given by Fisher can be derived by the method. For the monotone likelihood ratio family of distributions, which is a pivotal family, the fiducial distributions have a frequentist property in the Neyman-Pearson view. Fiducial distributions of regular parametric functions also have the above frequentist property. Some advantages of the fiducial inference are exhibited in four applications of the fiducial distribution. Many examples are given, in which the fiducial distributions cannot be derived by the existing methods. 相似文献
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本文利用广义p值和广义置信区间理论,研究了两独立服从双参数指数分布产品平均寿命比率的统计推断问题.给出了平均寿命比率的广义置信区间,并对该区间的覆盖率和区间长度进行了数据模拟,模拟结果与已有文献中的近似置信区间进行了比较,结果显示本文给出的广义置信区间的区间覆盖率和区间长度都要优于近似置信区间,特别是在小样本的情况下. 相似文献
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运用枢轴量法,借助于χ~2分布,就一般连续型非正态总体情形,证明了一类能够派生出总体分布中未知参数之精确置信区间构造方法的定理,并举例说明其应用. 相似文献
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Yichuan Zhao 《Statistics & probability letters》2011,81(5):603-610
Accelerated failure time (AFT) models are useful regression tools for studying the association between a survival time and covariates. Semiparametric inference procedures have been proposed in an extensive literature. Among these, use of an estimating equation which is monotone in the regression parameter and has some excellent properties was proposed by Fygenson and Ritov (1994). However, there is a serious under-coverage problem for small sample sizes. In this paper, we derive the limiting distribution of the empirical log-likelihood ratio for the regression parameter on the basis of the monotone estimating equations. Furthermore, the empirical likelihood (EL) confidence intervals/regions for the regression parameter are obtained. We conduct a simulation study in order to compare the proposed EL method with the normal approximation method. The simulation results suggest that the empirical likelihood based method outperforms the normal approximation based method in terms of coverage probability. Thus, the proposed EL method overcomes the under-coverage problem of the normal approximation method. 相似文献
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设备的平均寿命是可靠性研究中的的一个重要指标.对威布尔分布来说, 由于平均寿命没有明显的枢轴量,因此给出平均寿命的精确的置信限较为困难.本文分别利用广义枢轴量、WCF展开以及三阶法三种方法,得到了设备寿命服从威布尔分布时的平均寿命的(近似)置信下限.最后对上述三种方法分别进行了模拟比较,结果显示文中给出的方法对于中小样本情形下得到的平均寿命的置信限是比较精确的. 相似文献
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