冲击系统可靠度的界

对于处在冲击环境中的系统,在冲击模型(1)下,获得系统可靠度的界,而且在冲击模型(2)下,还获得类似的结果.对于一些特殊情况,所得结果更简洁.     

磁粉温度稳定性测量装置及测量方法

我们利用冲击差值补偿法,建立了一台测量磁粉温度稳定性的装置.该装置的灵敏度为2.1×10~4/mm,测量重复性为8×10~5.我们使用该装置测量了γ-Fe_2O_3等几种磁粉在使用温度范围附近的可逆和不可逆变化.包钴和掺钴的γ-Fe_2O_3磁粉的变化规律与报道的相符.对于普通的γ-Fe_2O_3,当温度从20℃上外到80℃时,剩余磁感应强度 Br 减少了5%;在这个温度范围内经五次循环以后,剩余磁感应强度随温度的变化是可逆的,其温度系数-5×10~4/℃.     

可靠性中的关联度分析法

在可靠性工程中,分布的拟合检验和点估计值的评价是经常遇到的两个问题。一般的处理方法是数理统计方法。本文利用灰色系统理论中的关联度概念,从几何处理的角度,提出一种新方法。该方法简单、使用方便、容易掌握,不需概率紙和特殊设计的统计量临界值表,适于对精确度要求不太高的场合。     

水在圆环形管道内层流对流换热的试验研究

本文研究水在圆环形管道中涉及流动和热入口段的非充分发展区的传热性能,并提出关于水在圆环形管道中换热性能的准则方程式。     

Sample size choice for reliability verification in strength-stress models

This paper discusses the choice of sample size for experiments concerned with inference on R = P(Y < X), where X and Y are normal variates, in an acceptance-sampling-theory framework. A conservative approach is derived, and the properties of this solution examined by simulation.     

基于Theil不等系数的组合预测模型的性质

基于Theil不等系数的组合预测模型是一种新的相关性的组合预测模型,研究了该模型的性质。在提出若干新概念的基础上,探讨了模型非劣性组合预测、优性组合预测以及冗余预测方法的存在性,给出了冗余信息的判定。     

Estimating Distributions with Increasing Failure Rate in an Imperfect Repair Model

A failed system is repaired minimally if after failure, it is restored to the working condition of an identical system of the same age. We extend the nonparametric maximum likelihood estimator(MLE) of a systems lifetime distribution function to test units that are known to have an increasing failure rate. Such items comprise a significant portion of working components in industry. The order-restricted MLE is shown to be consistent. Similar results hold for the Brown-Proschan imperfect repair model, which dictates that a failed component is repaired perfectly with some unknown probability, and is otherwise repaired minimally. The estimators derived are motivated and illustrated by failure data in the nuclear industry. Failure times for groups of emergency diesel generators and motor-driven pumps are analyzed using the order-restricted methods. The order-restricted estimators are consistent and show distinct differences from the ordinary MLEs. Simulation results suggest significant improvement in reliability estimation is available in many cases when component failure data exhibit the IFR property.     

基于遗传算法的分辨系数的优化方法

灰关联分析中分辨系数的选取会影响到分析结果的信息分辨程度,甚至灰关联序。把遗传算法和差异信息熵理论结合给出了优化分辨系数的方法。此方法把分辨系数作为优化变量,关联度序列的熵最小为优化目标,利用遗传算法的优化机制获得优化的分辨系数。最后,给出了一个计算实例。     

聚类系数无显著性差异下的灰色综合聚类方法研究

在灰色聚类评估分析中,当灰色聚类系数无显著性差异时,按照已有的灰色聚类方法无法对聚类对象进行准确的聚类,而在实际研究中经常会遇到聚类系数无显著性差异这类问题。因此本文提出了一种新的灰色综合聚类方法。具体步骤是:首先计算各聚类对象的聚类系数,并对其进行归一化处理;再根据对象中每一灰类的灰色聚类系数在聚类过程中的作用,计算聚类对象的综合聚类系数;最后根据综合聚类系数对聚类对象进行聚类,确定聚类对象应属的灰类。并且证明了当聚类对象的聚类系数差异大于1-2/S时,一般灰色聚类方法与灰色综合聚类方法所得聚类结果完全相同。最后,以江苏省第二产业内部主导产业选择为例进行了实证分析。     

CREDIBILITY THEORY: A CONCISE PARTIAL SURVEY1

Developments in credibility theory in the last seventy years or so are outlined. Particular attention is paid to early work in the field and to more recent developments showing some of the many connections between credibility theory and other fields including linear Bayesian theory, linear filtering theory and constant coefficient regression.