基于一种新模型对软件可靠度的估计

本文通过修改JM模型给出了一种新的软件可靠性模型,并对软件可靠度给出了点估计和置信限.对实际数据的分析表明这种新模型的预测能力比JM模型要好.     

定数截尾数据缺失场合下冷贮备串联系统可靠性指标的经验Bayes估计

在定数截尾缺失数据样本下,研究了冷贮备串联系统的可靠性指标评估问题.将经典估计方法和Bayes方法相结合得到了部件的平均寿命、系统可靠度及平均寿命等可靠性指标的Bayes点估计和区间估计.最后利用随机模拟例子说明了方法的正确性和可行性.     

K/n(G)系统可靠性评定的多源验前信息融合方法

在多源验前信息的情况下,以k/n(G)系统为例,讨论了如何对系统的可靠性指标进行估计的问题.在多个验前信息源给出了系统可靠性指标点估计的情况下,利用多层Bayes方法及经验Bayes方法对这些数据进行融合,并给出系统可靠性指标的Bayes点估计,同时对系统可靠度的置信区间也作了讨论.仿真算例表明这种处理方法是合理有效的.     

威布尔分布或极值分布可靠度置信下限的回归表示

对于定数截尾样本，给出了基于极值分布的位置和尺度参数的最好线性无偏估计（BLUE），获得了威布尔分布的可靠度的点估计和置信限之间的回归模型，从而可由威布 尔可靠度的点估计根据回归方程得到可靠度的置信下限，省去了大量的用表，为实际工作者带来了极大的方便，计算结果表明，回归方程有很高的精度。     

供应链网络可靠性的多层Bayes估计模型

对供应链网络可靠性进行界定和分析,以节点企业间的协同为基础,得到可靠度计算模型,以此为依据采集实证样本无失效运行的数据.根据供应链网络可靠性统计特性,建立一种多层Bayes估计方法,应用于样本可靠性评估中.在估计失效率的基础上,对供应链网络可靠度进行估计,对仿真结果进行分析,显示多层Bayes估计方法应用效果较好,精确度高,反映了参数不确定性对供应链网络可靠性的影响,能够较好地解决依据无失效数据判定供应链网络可靠性水平的问题.     

Gamma恒定应力加速寿命试验的统计分析

证明了基于恒定应力加速寿命试验数据Gamma模型参数的最大似然估计在一定条件下存在,进而导出了Gamma模型参数的备择估计.利用Cornish-Fisher展开导出了Gamma形状参数的近似置信区间,另外也给了Gamma模型的其它参数和正常应力水平下产品寿命的一些重要可靠性指标的广义置信区间.利用模拟方法研究了所给点估计和区间估计的精度,模拟结果显示所给点估计和区间估计的精度是相当好的.     

缺失数据下WEIBULL分布的统计推断

本文给出了定数截尾缺失数据下Weibull分布参数的点估计和区间估计以及可靠度、失效率的置信限。     

自适应逐步II型混合截尾恒加寿命试验下广义指数分布的统计分析

在自适应逐步II型混合截尾恒定应力加速寿命试验下,讨论了两参数广义指数分布的统计分析。利用EM算法和最小二乘法相结合的新方法推导出未知参数与可靠度函数的点估计,通过信息缺失原则得到了观测Fisher信息阵和尺度参数的渐近无偏估计。利用估计的渐近正态性和参数bootstrap方法构造了参数的置信区间。最后运用Monte-Carlo方法分别对得到的点估计和区间估计的精度进行研究,结果表明尺度参数的渐近无偏估计优于相应的两步估计, Boot-p置信区间比相应的渐近置信区间更精确。     

一种真空荧光屏的可靠性分析

基于真空荧光屏(VFD)寿命服从对数正态分布的条件,本文在逐次定数截尾样本下研究了VFD的平均寿命、失效率和可靠度的点估计及其置信下限.并利用Monte-Carlo方法对估计结果的优劣进行了分析比较,验证了结论的正确性和可行性.     

可靠性系列知识讲座 第四讲:可靠性增长试验的统计分析与设计

新产品的研制工作要经历若干个阶段,每个阶段都是在前一阶段的基础上针对产品在设计、材料或工艺等方面的缺点采取改进措施,以便产品的可靠度得到提高。本文在一般公认的假定—次序约束下,综合利用各阶段的数据给出了最后阶段产品可靠度的点估计和置信下限,它比只利用最后阶数据得到的点估计和置信下限更为合理。此处,还对可靠性增长试验的设计提出了有价值的建议。     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

Towards Excellence in Science Chinese Academy of Sciences

<正>May 26,2014,Beijing Science is a human enterprise in the pursuit of knowledge.The scientific revolution that occurred in the 17th Century initiated the advances of modern science.The scientific knowledge system created by     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.     

Boundedness of commutators related to Marcinkiewicz integrals on hardy type spaces

In this paper, the authors study the boundedness of the operator [μΩ, b], the commutator generated by a function b ∈ Lipβ(Rn)(0 ＜β≤ 1) and the Marcinkiewicz integrals μΩ, on the classical Hardy spaces and the Herz-type Hardy spaces in the case Ω∈ Lipα(Sn-1)(0 ＜α≤ 1).     

Generalization of the interaction between Haar approximation and polynomial operators to higher order methods

In applications it is useful to compute the local average empirical statistics on u. A very simple relation exists when of a function f（u） of an input u from the local averages are given by a Haar approximation. The question is to know if it holds for higher order approximation methods. To do so, it is necessary to use approximate product operators defined over linear approximation spaces. These products are characterized by a Strang and Fix like condition. An explicit construction of these product operators is exhibited for piecewise polynomial functions, using Hermite interpolation. The averaging relation which holds for the Haar approximation is then recovered when the product is defined by a two point Hermite interpolation.     

Jacobi polynomials used to invert the laplace transform

Given the Laplace transform F(s) of a function f(t), we develop a new algorithm to find an approximation to f(t) by the use of the classical Jacobi polynomials. The main contribution of our work is the development of a new and very effective method to determine the coefficients in the finite series expansion that approximation f(t) in terms of Jacobi polynomials. Some numerical examples are illustrated.