图的距离标号与频率分配问题

图的L(2,1)-标号问题由频率分配问题归结而来.图G的L(2,1)-标号是一个从顶点集V(G)到非负整数集的函数f(x),使得若d(x,y)=1,则|f(x)-f(y)|≥2;若d(x,y)=2,则|f(x)-f(y)|≥1.图G的L(2,1)-标号数λ(G)是使得G有max{f(v)v∈ V(G)}=k的L(2,1)-标号中的最小数k.本文将L(2,1)-标号问题推广到更一般的情形即L(4,3,2,1)标号问题,并得出了笛卡儿乘积图的λ4(G)的上界.     

基于平均产品长度的EWMA图性能评价与优化

在统计过程控制中,通常用平均运行长度(ARL)来度量控制图的性能,但是它的缺陷是度量不够精确.本文引入平均产品长度(APL)作为评价控制图性能的标准,首先用马尔可夫链的方法对EWMA图的平均产品长度进行计算,在此基础上讨论EWMA图的优化设计.通过与通用的EWMA设计方法的比较说明了本文提出的设计方法的优势.     

西部地区高技术产业创新效率研究——基于DEA和SFA方法的分析

一、创新效率的研究方法选择1.DEA模型。DEA(Data Envelopment Analysis)方法,即数据包络分析方法,设有n个DMU,每个DMU都有m个投入指标x和s个产出指标y,投入指标的权向量,产出指标的权向量,则第k个DMU的DEA相对绩效k h可以通过求解下面的公式规划问题来求解。     

对一个电学选择题的商榷

在《理科考试研究·物理版》(2003年4月10日)中有一篇文章,题目为《一个易被忽视的关键条件》中有这样一个选择题,题目如下:如图所示的电路R0为小于8Ω的定值电阻,现将3.6V,0.4A的甲灯与2.1V,0.3A的乙灯分别接入M、N两点间,比较两个灯泡的亮度(在两灯泡不烧坏的情况下),下列说法中正确的是( )     

基于最大熵分布的控制图改进与评价研究

传统的控制图多是假定质量特性参数服从正态分布,但在很多情况下正态分布的假设并不成立。本文基于最大熵分布从控制图的构建和评价两个方面分别提出对Shewhart控制图和CUSUM控制图的改进方法。首先根据"经济性"原则构建最大熵Shewhart控制图,实现对Shewhart控制图的改进;然后,提出结合最大熵分布和马尔科夫链方法的CUSUM控制图评价方法。仿真结果表明,基于最大熵分布改进后的Shewhart控制图控制性能优于改进之前的情况;而基于最大熵分布的CUSUM控制图的性能评价方法得到的结果能更符合真实的情况。在对不同偏移的监测中,最大熵Shewhart控制图更适用于分布未知的大偏移情况,而自适应CUSUM控制图对小偏移有更好地监控效果。     

面向多极值质量特性的过程参数全局优化研究

对于作用关系复杂,而且质量特性拥有多个极值的制造过程,现有质量改进方法只能实现参数的局部优化,产品质量仍有较大改进空间.本文采用支持向量机(SVM)作为复杂作用关系过程的近似模型,提出基于支持向量聚类(SV)与序列二次规划(SQP)的参数全局性优化方法.首先建立了复杂过程的SVM近似模型;而后根据ε管道理论,通过对聚类过程谱系图的分析,确定了聚类的最小相似度水平及合适的聚类数目,将过程各极值点邻域内的支持向量分别聚为一类;最后由各聚类中心出发,并行进行SQP寻优以发现过程的多个极值.仿真研究表明,所提方法能够全面反映过程的极值分布,实现参数的全局性优化;寻优结果与实际极值的绝对偏差及相对偏差的平均值分别为0.15和1.28%,并且偏差的大小与过程极值的数目无关,说明方法具有较高的精确度和稳定性;此外,通过支持向量聚类,不仅保证了SQP寻优结果对于过程全部极值的遍历性,而且将寻优的次数降低了50%以上,提高了寻优效率.     

基于支持向量机的R&D项目过程质量度量

过程质量度量是项目质量控制中的基础。本文针对R＆D项目的质量特性,构建了R＆D项目过程质量状况的评价指标体系,将支持向量机(SVM)技术应用于R＆D项目过程质量度量。实证研究结果表明该方法可很好地应用于R＆D项目的过程质量管理。     

基于IPV6的移动泛在学习架构选择

课题组通过搜集,主要研究机构发布的讨论组、研究成果、会议和论文索引中IPV6研究相关的E- learning(电子学习),M-learning(移动学习)、U-learning (泛在学习)3个研究方向的第一手资料,运用在统计语言模型的基础上自主开发的基于文本搜索引擎的关注度评价统计模型量化评价各机构对基于移动泛在网络的研究方向的关注度,为基于IPV6的移动泛在学习架构的选择提供参考。     

企业内部控制质量对上市公司经营绩效影响研究——基于制造业上市公司的实证研究

本文实证研究分析企业内部控制质量对上市公司经营绩效的影响及其作用机理,从制度安排角度寻找提升上市公司经营绩效的企业内部控制机制,并为我国提升企业内部控制质量提供理论指导和发展方向。实证结果提供了不同产权制度条件下,企业内部控制质量影响上市公司经营绩效的深入证据,为加强企业内部控制制度建设提供了施政依据。     

基于交互密度算子的交互式群体评价信息集结方法及其应用

交互式群体评价的一个难点问题是评价信息的集结问题,而国内较少有文献从信息集结算子的角度进行探讨,针对这种不足,同时考虑到信息分布密度是交互式群体评价信息集结的一个重要特征,本文提出了一种基于交互密度算子的交互式群体评价信息集结方法。提出了交互密度算术加权算子(IDWA)与交互密度几何加权算子(IDWGA)两种新的算子,并对新算子的相关性质进行了分析,同时介绍了IDWA和IDWGA算子加权向量(即密度权向量)的确定方法。最后将该方法进行了运用。文章对交互式评价信息集结问题提供了一种新的研究思路。     

USING RUN-LENGTH DISTRIBUTIONS OF CONTROL CHARTS TO DETECT FALSE ALARMS

Run-length distributions for various statistical process-control charts and techniques for computing them recently have been reported in the literature. The real advantages of knowing the run-length distribution for a process-control chart versus knowing only the associated average-run length of the chart have not been exploited. Our purpose is to use knowledge of the run-length distribution as an aid in deciding if an out-of-control signal is a true signal or merely a false alarm. The ability to distinguish between true and false signals is important, especially in operations where it is costly to investigate the causes of out-of-control conditions. Knowledge of the run-length distribution allows us to compute likelihood ratios, which are simple to calculate and to interpret and which are used to determine the odds of obtaining an out-of-control signal at a particular run length when a shift in the process mean actually has occurred vis-a-vis no such shift. We extend our analysis in a Bayesian sense by incorporating prior information on the distribution of the shift size of the process mean, combined with the likelihood ratio obtained from the run-length distribution, to determine if a shift larger than a critical size has occurred. We give examples for the Shewhart chart, the exponentially weighted moving-average chart, and the special-cause control chart for processes with autocorrelated observations. The examples show that the current recommended usage of the average-run length alone as a guide for determining whether a signal is a false alarm or otherwise can be misleading. We also show that the performance of the traditional charts, in terms of their average-run length, can be enhanced in many instances by using the likelihood-ratio procedure.     

Probabilistic and membership approaches in the construction of control charts for linguistic data

Abstract

Two approaches for constructing control charts for quality assurance when the observations are in the form of linguistic data are presented. Both approaches are based on fuzzy set theory and use fuzzy subsets to model the linguistic terms used to describe product quality. They differ in the interpretation of the control limits and in the procedure used to reduce the fuzzy subsets to scalars for determining the chart parameters. The results obtained with simulated data suggest that, on the basis of sensitivity to process shifts, the control charts for linguistic data perform better than conventional p control charts. The number of linguistic terms used in classifying the observations was found to influence the sensitivity of these control charts. The transformation method used to obtain the representative values and the amount of fuzziness do not seem to affect the performance of either type of control charts.     

Application of control charts in analytic hierarchy process

Vendor rating can be done using the Analytic Hierarchy Process (AHP) by a single decision maker or a group of decision makers. This approach may suffer from some drawbacks including bias in estimation process. The proposed methodology in this paper involves estimation by a group on an individual basis following the principle of anonymity. A control chart is constructed with an upper control limit and a lower control limit. Implementation ofthiscontrol chart will take into account the dynamic nature of vendor performance and also can be used for continuous monitoring of the vendor performance. This procedure can be used for a single vendor as well as for multiple vendor rating.     

Conditional Monte Carlo Gradient Estimation in Economic Design of Control Limits

The economic approach to determining the optimal control limits of control charts requires estimating the gradient of the expected cost function. Simulation is a very general methodology for estimating the expected costs, but for estimating the gradient, straightforward finite difference estimators can be inefficient. We demonstrate an alternative approach based on smoothed perturbation analysis (SPA), also known as conditional Monte Carlo. Numerical results and consequent design insights are obtained in determining the optimal control limits for exponentially weighted moving average and Bayes charts. The results indicate that the SPA gradient estimators can be significantly more efficient than finite difference estimators, and that a simulation approach using these estimators provides a viable alternative to other numerical solution techniques for the economic design problem.     

Using Shainin DOE for Six Sigma: an Indian case study

Shainin design of experiments (DOE) offers a powerful and effective experimental design approach for solving the chronic quality problems that plague manufacturers worldwide. However, the academic literature still contains a few empirical studies on the use of non-statistical Shainin DOE tools to simplify the quality improvement initiatives. In order to overcome this deficiency, this case describes framework for incorporating Shainin experimental design within Six Sigma define–measure–analyse–improve–control and tests its effectiveness in an Indian automotive gear manufacturing unit. Shainin tools such as Paired Comparison, Product/Process search, Concentration chart, B vs. C analysis, Pre-control chart were employed to analyse, improve and control the gear manufacturing process. The study provides stimulus for the wider application of Shainin experimental design approach for industrial experimentation.     

考虑维修服务质量的产品质保联合决策

在售后服务竞争日益激烈的大环境下,维修服务质量对于企业的意义越来越重要。经典的质保决策问题通常关心质保期和产品价格的联合决策问题,本文在此基础上进一步考虑了质保维修的服务质量问题。质保期、产品价格以及维修服务质量在产品生命周期内存在动态的关联关系,目前同时考虑此三类因素的研究尚不多见。本文以具有重复购买行为的大众消费品为研究对象,构建了包括成本模型、需求模型、利润模型在内的最优控制模型,并应用最大化原理对模型进行求解分析,在此基础上进一步对最优策略在静态市场和动态市场的应用分别做了具体分析和数值试验。     

Statistical Process Control and Condition‐Based Maintenance: A Meaningful Relationship through Data Sharing

This paper focuses on the close relationship between statistical process control and preventive maintenance (PM) of manufacturing equipment. The context is very general: a production process that is characterized by multiple distinct operational states and a failure state. The operational states differ in terms of operational/quality costs and/or the proneness to complete failure. The times of shift from the normal operational state to an inferior one and the times to failure are random variables, not necessarily exponentially distributed. The process is monitored with a control chart with the purpose of quickly detecting shifts to an inferior operational state due to the occurrence of some unobservable assignable cause. At the same time, the information collected from the process may be used to re‐schedule the planned PM, if there is evidence that a failure is imminent. The two mechanisms are obviously related, especially if they are based on measurements of the same critical process characteristic. Yet, they are typically treated independently. We develop a fairly general mathematical model for the joint optimization of the control chart parameters and the maintenance times. Numerical investigation using this model shows that ignoring the close relationship between process control and maintenance results in inefficiencies that may be substantial. It also provides practical insights about the effects of some key problem characteristics on the optimal joint design of process control and maintenance.     

需求不确定下双渠道供应链产品质量控制研究

考虑到电商平台与实体门店两种渠道参与主体的质量决策对不同渠道产品质量水平的影响,进而引致两种渠道下供应链产品质量与价格的市场竞争。本文运用stackblerg博弈分析模型,研究由制造商、实体门店、电商平台与消费者组成的双渠道供应链产品质量控制问题。在考虑需求不确定性的基础上,构建双渠道下制造商、实体门店和电商平台收益分析模型,分析双渠道下制造商与实体门店的批发价格契约、制造商与电商平台之间收益共享契约两种策略对供应链产品质量控制水平的影响,通过运用最优化原理求解制造商、实体门店和电商平台物流配送的最优质量控制水平,并对结果进行仿真模拟。结果显示：制造商、实体门店和电商平台之间的契约对三方产品质量控制具有交互影响,电商平台物流配送质量水平与实体门店仓储质量水平呈同方向变化,而实体门店产品市场售格的提高则不利于电商平台加强物流配送质量水平,消费者对产品售格敏感性越高,制造商越注重产品质量提升。反之,消费者对仓储和物流配送质量水平敏感性提高,并不利于制造商加强产品质量控制。因此,通过大力发展物流配送服务业,提升产品物流配送质量控制水平,不仅有助于生产环节质量控制,同时也将促使实体门店加强产品仓储质量控制水平。     

Non-Normality and the Design of Control Charts for Averages*

Non-normality has a significant effect on the performance of control charts for averages. The design considerations for a control chart for averages must include recognition of the degree of non-normality of the underlying data. The performance of a control chart may be judged on its ability to correctly identify the probabilities of assignable causes of variation and chance causes of variation in a process. This paper examines the effects of non-normality, as measured by skewness and kurtosis, on the performance, and hence the design, of control charts for averages and provides an alternative method of designing charts for averages of data with non-normal distributions.