Stochastics and Quality Control最新文献_第2页

Design and Optimization of c-Control Chart Using a Triple Sampling Scheme 三次抽样c-控制图的设计与优化

Stochastics and Quality Control Pub Date : 2023-07-25 DOI: 10.1515/eqc-2023-0012

José Jorge Muñoz, Manuel J. Campuzano, Verónica Deibe-Blanco

引用次数: 0

Frontmatter 头版头条

Stochastics and Quality Control Pub Date : 2023-06-01 DOI: 10.1515/eqc-2023-frontmatter1

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An Extension of Yang and Rahim’s Model to Determine Design Parameters in Multivariate Control Charts Under Multiple Assignable Causes and Weibull Shock Model 多可分配原因下多元控制图设计参数确定的Yang和Rahim模型的推广及威布尔冲击模型

Stochastics and Quality Control Pub Date : 2023-05-31 DOI: 10.1515/eqc-2022-0053

Rahmat Shojaei, M. Bameni Moghadam

{"title":"An Extension of Yang and Rahim’s Model to Determine Design Parameters in Multivariate Control Charts Under Multiple Assignable Causes and Weibull Shock Model","authors":"Rahmat Shojaei, M. Bameni Moghadam","doi":"10.1515/eqc-2022-0053","DOIUrl":"https://doi.org/10.1515/eqc-2022-0053","url":null,"abstract":"Abstract One of the most important issues in the operation of any one- or multi-variable control chart is to determine the design parameters. Because in practice, production processes are affected by several assignable causes, several papers have been published to determine the design parameters. In all the papers presented so far, it has been assumed that after the occurrence of one of the assignable causes until the issuance of the true alarm, no other assignable cause occurs. Contrary to popular opinion, this paper argues that the formulas presented under this assumption for the average cost and quality cycle time in previous papers are incorrect and shows how the formula can be corrected. Therefore, this paper theoretically and numerically examines the conditions of occurrence of this assumption and its relationship with the design parameters in the design of multivariate control charts. A new economic model for determining design parameters is also presented. Numerical results show that the old formulas have a significant under-estimation of the average cost per unit time of the quality cycle. Also, a numerical study for economic and economic-statistical design of T 2 {T^{2}} control chart is presented under the proposed model.","PeriodicalId":37499,"journal":{"name":"Stochastics and Quality Control","volume":"47 1","pages":"25 - 46"},"PeriodicalIF":0.0,"publicationDate":"2023-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74257450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Reliability Estimation of Parallel Repairable System under Uncertainty in Lifetime Data 寿命数据不确定下并联可修系统可靠性估计

Stochastics and Quality Control Pub Date : 2023-05-03 DOI: 10.1515/eqc-2022-0044

Sruthi K., Mahesh Kumar

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An ARL-Unbiased Modified np-Chart for Autoregressive Binomial Counts 自回归二项计数的arl无偏修正np图

Stochastics and Quality Control Pub Date : 2023-03-31 DOI: 10.1515/eqc-2022-0052

M. Morais, P. Wittenberg, Camila Jeppesen Cruz

{"title":"An ARL-Unbiased Modified np-Chart for Autoregressive Binomial Counts","authors":"M. Morais, P. Wittenberg, Camila Jeppesen Cruz","doi":"10.1515/eqc-2022-0052","DOIUrl":"https://doi.org/10.1515/eqc-2022-0052","url":null,"abstract":"Abstract Independence between successive counts is not a sensible premise while dealing, for instance, with very high sampling rates. After assessing the impact of falsely assuming independent binomial counts in the performance of np-charts, such as the one with 3-σ control limits, we propose a modified np-chart for monitoring first-order autoregressive counts with binomial marginals. This simple chart has an in-control average run length (ARL) larger than any out-of-control ARL, i.e., it is ARL-unbiased. Moreover, the ARL-unbiased modified np-chart triggers a signal at sample t with probability one if the observed value of the control statistic is beyond the lower and upper control limits L and U. In addition to this, the chart emits a signal with probability γ L {gamma_{L}} (resp. γ U {gamma_{U}} ) if that observed value coincides with L (resp. U). This randomization allows us to set the control limits in such a way that the in-control ARL takes the desired value ARL 0 {operatorname{ARL}_{0}} , in contrast to traditional charts with discrete control statistics. Several illustrations of the ARL-unbiased modified np-chart are provided, using the statistical software R and resorting to real and simulated data.","PeriodicalId":37499,"journal":{"name":"Stochastics and Quality Control","volume":"52 1","pages":"11 - 24"},"PeriodicalIF":0.0,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78822353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

General Independent Competing Risks for Maintenance Analysis 维护分析的一般独立竞争风险

Stochastics and Quality Control Pub Date : 2022-11-25 DOI: 10.1515/eqc-2022-0029

Makram Krit

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On Normal-Laplace Stochastic Volatility Model 关于正态拉普拉斯随机波动模型

Stochastics and Quality Control Pub Date : 2022-11-23 DOI: 10.1515/eqc-2022-0013

Shiji Kavungal, Rahul Thekkedath

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Estimation and Confidence Intervals of Modified Process Capability Index Using Robust Measure of Variability 基于鲁棒变异性的改进过程能力指数估计及置信区间

Stochastics and Quality Control Pub Date : 2022-11-02 DOI: 10.1515/eqc-2022-0014

Mahendra Saha, S. Dey

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Robust Optimization of an Imperfect Process when the Mean and Variance are Jointly Monitored under Dependent Multiple Assignable Causes 多可分配原因下均值和方差联合监测不完美过程的鲁棒优化

Stochastics and Quality Control Pub Date : 2022-10-28 DOI: 10.1515/eqc-2022-0018

A. Salmasnia, samrad Jafarian-Namin, Behnam Abdzadeh

{"title":"Robust Optimization of an Imperfect Process when the Mean and Variance are Jointly Monitored under Dependent Multiple Assignable Causes","authors":"A. Salmasnia, samrad Jafarian-Namin, Behnam Abdzadeh","doi":"10.1515/eqc-2022-0018","DOIUrl":"https://doi.org/10.1515/eqc-2022-0018","url":null,"abstract":"Abstract Imperfect processes experience fault productions over time due to specific causes. Integrating the statistical process control, maintenance policy, and economic production quantity has led to more favorable results for the imperfect processes in literature. When monitoring a process, multiple assignable causes (ACs) may shift it to an out-of-control state. As indicated recently, if the interdependency of ACs is neglected, the total cost will be underestimated. Moreover, the mean and variance can simultaneously be affected by the occurrence of ACs. A non-central chi-square (NCS) chart was suggested for its decent performance against X-R chart in detecting the process disturbances and lowering quality loss cost. Besides, the increased occurrence rate of ACs over time leads to higher quality and maintenance costs. Employing a non-uniform sampling (NUS) scheme can significantly reduce costs. In the literature of modeling for imperfect processes under multiple ACs, all input parameters have always been fixed. The effectiveness of the models depends somewhat on the accurate estimates of these parameters. In reality, the estimation of parameters may be associated with uncertainty. For the first time, a robust design approach is proposed for designing NCS chart by considering the interval estimation of uncertain parameters. A particle swarm optimization (PSO) algorithm is used to present solutions. The proposed model is investigated through a real numerical example.","PeriodicalId":37499,"journal":{"name":"Stochastics and Quality Control","volume":"38 1","pages":"137 - 151"},"PeriodicalIF":0.0,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73617968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The 𝑛𝑝-Chart with 3-𝜎 Limits and the ARL-Unbiased 𝑛𝑝-Chart Revisited 重新考察了3-限的𝑛𝑝-Chart和arl无偏的𝑛𝑝-Chart

Stochastics and Quality Control Pub Date : 2022-10-27 DOI: 10.1515/eqc-2022-0032

M. Morais, P. Wittenberg, Camila Jeppesen Cruz

{"title":"The 𝑛𝑝-Chart with 3-𝜎 Limits and the ARL-Unbiased 𝑛𝑝-Chart Revisited","authors":"M. Morais, P. Wittenberg, Camila Jeppesen Cruz","doi":"10.1515/eqc-2022-0032","DOIUrl":"https://doi.org/10.1515/eqc-2022-0032","url":null,"abstract":"Abstract In the statistical process control literature, counts of nonconforming items are frequently assumed to be independent and have a binomial distribution with parameters ( n , p ) (n,p) , where 𝑛 and 𝑝 represent the fixed sample size and the fraction nonconforming. In this paper, the traditional n ⁢ p np -chart with 3-𝜎 control limits is reexamined. We show that, even if its lower control limit is positive and we are dealing with a small target value p 0 p_{0} of the fraction nonconforming ( p ) (p) , this chart average run length (ARL) function achieves a maximum to the left of p 0 p_{0} . Moreover, the in-control ARL of this popular chart is also shown to vary considerably with the fixed sample size 𝑛. We also look closely at the ARL function of the ARL-unbiased n ⁢ p np -chart proposed by Morais [An ARL-unbiased n ⁢ p np -chart, Econ. Qual. Control 31 (2016), 1, 11–21], which attains a pre-specified maximum value in the in-control situation. This chart triggers a signal at sample 𝑡 with probability one if the observed number of nonconforming items, x t x_{t} , is beyond the lower and upper control limits (𝐿 and 𝑈), probability γ L gamma_{L} (resp. γ U gamma_{U} ) if x t x_{t} coincides with 𝐿 (resp. 𝑈). A graphical display for the ARL-unbiased n ⁢ p np -chart is proposed, taking advantage of the qcc package for the statistical software R. Furthermore, as far as we have investigated, its control limits can be obtained using three different search algorithms; their computation times are thoroughly compared.","PeriodicalId":37499,"journal":{"name":"Stochastics and Quality Control","volume":"42 1","pages":"107 - 116"},"PeriodicalIF":0.0,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87634609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1