预控法──一种代替X-R控制图的好方法

近几年来,在美国人们对X—R控制图再次发生兴趣.这种兴趣的出现,是与人们对美国产品质量与日俱增的担忧,以及探索经济有效的提高产品质量的途径相关联的.为迅速适应这种趋势,美国的一些质量管理工程师开始在他们的公司内广泛地设置了大量的X—R控制图. X—R控制图,如能正确运用,就能成为工序控制的一种非常有效的工具.但在很多情况下,特别是在使用现场中,它的缺点比它的优点更显得突出.X—R控制图要求生产人员或检查人员记录数据、计算X和R,并在图上打点.有些人还得收集控制图,重新计算控制界限,更换控制图等.加工周期短的工序,常常还未…     

消去图、覆盖图和均匀图的若干结果

设 G是一个图 ,g,f是定义在图 G的顶点集上的两个整数值函数 ,且g≤f.图 G的一个 ( g,f) -因子是 G的一个支撑子图 F,使对任意的 x∈V( F)有g( x)≤ d F( x)≤ f ( x) .文中推广了 ( g,f) -消去图、( g,f ) -覆盖图和 ( g,f) -均匀图的概念 ,给出了在 g相似文献   

和图、整和图与模和图的几个结果

Let N denote the set of positive integers. The sum graph G^＋（S） of a finite subset S belong to N is the graph （S, E） with uv ∈ E if and only if u ＋ v ∈ S. A graph G is said to be a sum graph if it is isomorphic to the sum graph of some S belong to N. By using the set Z of all integers instead of N, we obtain the definition of the integral sum graph. A graph G = （V, E） is a mod sum graph if there exists a positive integer z and a labelling, λ, of the vertices of G with distinct elements from {0, 1, 2,..., z - 1} so that uv ∈ E if and only if the sum, modulo z, of the labels assigned to u and v is the label of a vertex of G. In this paper, we prove that flower tree is integral sum graph. We prove that Dutch m-wind-mill （Dm） is integral sum graph and mod sum graph, and give the sum number of Dm.     

Bubble-sort图和Modified Bubble-sort图的自同构群

Bubble-Sort图和Modified Bubble-Sort图是两类特殊的Cayley图,由于其在网络构建中的应用而受到广泛关注.本文完全确定了这两类图的自同构群.     

图的子图序列和图的子林分解

在文献[1]里,Michael.O.Albertson和David Berman对任意图G定义了一个函数f(G): 他们猜想当G是平面图时,f(G)的下界至少是1/2。如果这个猜想成立,则可以利用这结果,而不用四色定理来解决Erds-Vising问题.(在文献[2],251页,问题36).同时他们提出了对于其它类型图G,f(G)的下界问题.本文首先引进了子图序列概念,并用它作为工具来估计f(G)的下界.主要给出了在亏格大于零的定向曲面上图G的f(G)下确界。     

探针区间图和STS-探针区间图的刻划

该文首先引入了探针区间序来刻划探针区间图;接着给出STS-探针区间图的探针区间完备的一种构造方法,并借此得到二部图G是相对于给定顶点划分的STS-探针区间图的一个充要条件;同时也说明了STS-探针区间图其实就是其他文献中被独立研究的凸二部图.最后基于前面给出的STS-探针区间图的刻划结果提供了两种简单的O(V E)时间的STS-探针区间图的判别算法.     

一种多指标质量动态控制图及其应用

研究了将多指标在一个图上标示的多指标控制图。提出了三种质量控制限并作了比较。控制上限(UCL)取Hotelling的T2统计量的α/2上侧分位数。预控上限(UPCL)取Hotelling的T2统计量的λα/2上侧分位数。当第k个观测点的T2k值超过UPCL时,则接下去的抽样区间将缩短,以便及早发现失控状态。对超出控制限的情况下如何确定哪一个质量指标发生异常的问题,提出了一种可靠的分析方法。用这种方法解决了某卷烟厂的烟丝生产过程中的多指标质量控制和管理问题。     

书本图Bm的协调和相继标号

本文给出了书本图Ｂ２ｍ的ｍ种不同的相继标号和Ｂ４ｍ＋１的ｍ种不同的相继标号。因而，书本图Ｂｍ是相继图的充分条件为：ｍ＞１且ｍ≠（３ｍｏｄ４）。这一条件也是书本图Ｂｍ是协调图的充要条件。     

轮图和多轮图的生成树的计数

本文应用计算生成树个数的有向图方法、分块矩阵的行列式计算法以及常系数线性递归方程的解法 ,计算得到轮图和多轮图的生成树个数的表达式 (显式或递推式 )     

合成控制图

本文提出了一种新的组合控制图 ,介绍了它的用法 ,导出了控制限常数 ,并将它和传统的 X图与 X-EWMA 图作了比较。模拟研究表明 ,新图更有效     

合格品链长控制图

在生产过程中不合格品率(p)很低的情况下,利用两个连续不合格品之间的合格品数(合格品链长)控制图来监督过程不合格品率能克服传统的p图所遇到的困难,为生产者提供产品质量改良的信息。本文研究两种合格品链长(CRL)控制图的制定方法,对这些控制图的效率进行了比较,并说明其实际应用。所研究的CRL控制图特别适用于自动化生产过程的100%检验的质量控制。     

Economic design of integrated model of control chart and maintenance management

There are two key tools for the control of production processes — Statistical Process Control (SPC) and Maintenance Management (MM), which are traditionally separated (both in science and in business practice), even though their goals overlap a great deal. Their common goal is to achieve optimal product quality, little downtime and cost reduction by controlling variances in the process. Since single or separated parallel applications may not be fully effective, this paper discusses the integration of statistical process control and maintenance, and provides an integrated model of Control Chart (CC) and MM. A mathematical model is given to analyze the cost of the integrated model and the grid-search approach is used to find the optimal values of policy variables (n,h,L,k) that minimize hourly cost. Finally, a numerical experiment is conducted to investigate the effects of cost parameters on the solution of the design.     

A process variability control chart

In this study a Shewhart type control chart namely the V _t chart, is proposed for improved monitoring of the process variability of a quality characteristic of interest Y. The proposed control chart is based on the ratio type estimator of the variance using a single auxiliary variable X. It is assumed that (Y, X) follows a bivariate normal distribution. The design structure of the V _t chart is developed for Phase-I quality control and its comparison is made with those of the S ² chart (a well-known Shewhart control chart) and the V _r chart (a Shewhart type control chart proposed by Riaz (Comput Stat, 2008a) used for the same purpose. It is observed that the proposed V _t chart outperforms the S ² and V _r charts, in terms of discriminatory power, for detecting moderate to large shifts in the process variability. It is observed that the performance of the V _t chart keeps improving with an increase in |ρ _yx | , where ρ _yx is the correlation between Y and X.     

在固定时间抽样的可变抽样区间的极值控制图

本文根据 Reynolds在固定时间抽样的可变抽样区间 (VSIFT)的 - x控制图 [1 ]的模型设计极值 (ζ)图。规定样本在相等间隔的固定时间点抽取 ,当过程有变化的迹象时 ,允许在两个固定时间之间抽取附加样本。若样本点超过控制限 ,则 VSIFT图同常规图一样发信号。本文计算了 VSIFTζ图的发信号前的平均时间 ,并同固定抽样区间 (FSI)的常规ζ图作比较。极值图不需计算 ,有关集中和分散的信息在一个图上给出 ,且可画上规格限 ,在实践中应用方便。本文设计的 VSIFTζ图能缩短过程失控时间从而减少不合格品数     

A new control chart in contaminated data of t‐Student distribution for individual observations

Control charts are the most popular tool for monitoring production quality. In traditional control charts, it is usually supposed that the observations follow a multivariate normal distribution. Nevertheless, there are many practical applications where the normality assumption is not fulfilled. Furthermore, the performance of these charts in the presence of measurement errors (outliers) in the historical data has been improved using robust control charts when the observations follow a normal distribution. In this paper, we develop a new control chart for t‐Student data based on the trimmed T² control chart () through the adaptation of the elements of this chart to the case of this distribution. Simulation studies show that a control chart performs better than T² in t‐Student samples for individual observations. Copyright © 2012 John Wiley & Sons, Ltd.     

概率逻辑伪度量空间及其性质

论证有限多个公式的概率分布与生成它的原子公式集的概率分布之间的关系,然后把计量逻辑学与概率逻辑学相结合,提出了概率真度、概率逻辑伪度量空间(F(n),ρP);指出当取均匀概率分布时,概率真度就转化为计量逻辑学中的真度,同时两公式间的概率逻辑伪距离Pρ就转化为计量逻辑学中的伪距离ρ.从而在有限理论中建立了一种更具一般性的概率逻辑伪度量空间理论。     

分块初等方阵及其应用

本文我们先引入分块初等矩阵的概念，然后说明它的一些应用．     

A simulation-based multivariate Bayesian control chart for real time condition-based maintenance of complex systems

When complex systems are monitored, multi-observations from several sensors or sources may be available. These observations can be fused through Bayesian theory to give a posterior probabilistic estimate of the underlying state which is often not directly observable. This forms the basis of a Bayesian control chart where the estimated posterior probability of the state can be compared with a preset threshold level to assess whether a full inspection is needed or not. Maintenance can then be carried out if indicated as necessary by the inspection. This paper considers the design of such multivariate Bayesian control chart where both the transition between states and the relationship between observed information and the state are not Markovian. Since analytical or numerical solutions are difficult for the case considered in this paper, Monte Carlo simulation is used to obtain the optimal control chart parameters, which are the monitoring interval and the upper control limit. A two-stage failure process characterised by the delay time concept is used to describe the underlying state transition process and Bayesian theory is used to compute the posterior probability of the underlying state, which is embedded in the simulation algorithm. Extensive examples are shown to demonstrate the modelling idea.     

Economic design of an attribute control chart for monitoring mean life based on multiple deferred state sampling

In this paper, we design an attribute np control chart using multiple deferred state (MDS) sampling under Weibull distribution based on time truncated life test. This chart is constructed for monitoring the variation of mean life of the product in a manufacturing process. The optimal parameters of MDS sampling and the control limit coefficients are determined so that the in‐control average run length (ARL) is as close as to the target ARL. The optimal parameters of MDS sampling are sample size and number of successive subgroups required for declaring the current state of process. Out‐of‐control ARL is considered as a measure of the performance of proposed chart and reported with determined optimal parameters for various shift constants. The out‐of‐control ARL of the proposed chart obtained under various distributions is compared with each other. The performance of proposed control chart is compared with the performance of the existing control chart designed under single sampling. In addition, the economic design of proposed chart using variable sampling interval scheme is discussed, and sensitivity analysis on expected costs is also investigated.