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1.
《Quality Engineering》2012,24(3):237-246
ABSTRACT The present article proposes the skip lot sampling plan of type SkSP-2 using a group acceptance sampling plan for a time-truncated experiment as the reference plan, called SkGSP-2, when the lifetime of a product follows either the Weibull distribution or the generalized exponential distribution. The percentile life is used as the product quality in the proposed plan because assuring the percentile life is more practical than assuring the mean lifetime. The plan parameters such as the number of groups and the acceptance number are determined such that the specified values of producer's risk and consumer's risk are satisfied simultaneously. Extensive tables are provided for the selection of plan parameters according to various values of experiment time, percentiles ratios, and group size. Real-life examples are also given to illustrate the operation of the proposed plan. 相似文献
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Radman Rahimi Yeganeh Mona Ayoubi 《Quality and Reliability Engineering International》2024,40(2):1026-1041
This study compares two proposed mixed quick switching sampling (QSS) plans for linear profiles as the quality characteristic. For the QSS plans, we recommend a binomial attribute plan for normal inspection and then a variable sampling plan for tightened inspection based on capability index CpuA of linear profiles with one-sided specifications. The difference between the two proposed QSS plans is in the tightened inspection. Tightened inspection of the first proposed plan is a single sampling using CpuA index, but tightened inspection of the second plan is a multiple dependent state repetitive (MDSR) plan based on CpuA index. The optimal parameters are obtained by nonlinear optimization. Simulation study for selecting parameters is conducted with various combinations of specified acceptable quality level (AQL), limited quality level (LQL), producer's risk, and consumer's risk. Simulation results confirm that the second proposed QSS plan which applies variable MDSR at tightened inspection performs better than another proposed plan. Hence, the approach of the second proposed plan is demonstrated in an illustrative example. 相似文献
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ABSTRACTReliability demonstration tests have important applications in reliability assurance activities to demonstrate product quality over time and safeguard companies’ market positions and competitiveness. With greatly increasing global market competition, conventional binomial reliability demonstration tests based on binary test outcomes (success or failure) at a single time point become insufficient for meeting consumers’ diverse requirements. This article proposes multi-state reliability demonstration tests (MSRDTs) for demonstrating reliability at multiple time periods or involving multiple failure modes. The design strategy for MSRDTs employs a Bayesian approach to allow incorporation of prior knowledge, which has the potential to reduce the test sample size. Simultaneous demonstration of multiple objectives can be achieved and critical requirements specified to avoid early/critical failures can be explicitly demonstrated to ensure high customer satisfaction. Two case studies are explored to demonstrate the proposed test plans for different objectives. 相似文献
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In material engineering application, the failure time of material due to weakness in material (fatigue) is usually caused by repeated variations of stress. The failure time is modeled by statistical distributions. In this article, an attribute multiple state repetitive group sampling plan is developed assuming that the life time follows the Burr Type XII distribution. The plan parameters are determined by considering two points on operating characteristic (OC) curve. Tables are given for the practical use. The advantages of the proposed plan are discussed over the single sampling plans. Examples are given to illustrate the proposed plan. 相似文献
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《Quality and Reliability Engineering International》2018,34(6):1174-1184
In this paper, we propose 3 new sampling plans, including resubmitted single sampling plan (RSSP), repetitive group sampling (RGS) plan, and multiple dependent state (MDS) sampling plan to study the zero‐inflated negative binomial distribution in microbiological food safety and quality assurance practices. The unity value approach is used to find optimal plan parameters. The proposed plans are compared with the single sampling plan (SSP). We found that degree of clustering and excess of zeros counts affect the performance of all sampling plans. The MDS plan outperforms the SSP, RSSP, and RGS plans with respect to minimum average sample number in most cases. Both RGS and MDS plans show a comparable performance. The average run length is calculated to evaluate the rejection capability of the plans and signal the deterioration of the quality of lots. An example from 9 Irish abattoirs is used to illustrate the application of the proposed methods. 相似文献
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In this paper, we considered the Length-biased weighted Lomax distribution and constructed new acceptance sampling plans (ASPs) where the life test is assumed to be truncated at a pre-assigned time. For the new suggested ASPs, the tables of the minimum samples sizes needed to assert a specific mean life of the test units are obtained. In addition, the values of the corresponding operating characteristic function and the associated producer’s risks are calculated. Analyses of two real data sets are presented to investigate the applicability of the proposed acceptance sampling plans; one data set contains the first failure of 20 small electric carts, and the other data set contains the failure times of the air conditioning system of an airplane. Comparisons are made between the proposed acceptance sampling plans and some existing acceptance sampling plans considered in this study based on the minimum sample sizes. It is observed that the samples sizes based on the proposed acceptance sampling plans are less than their competitors considered in this study. The suggested acceptance sampling plans are recommended for practitioners in the field. 相似文献
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Linda Lee Ho Airlane Pereira Alencar 《Quality and Reliability Engineering International》2013,29(6):855-867
To monitor the nonconforming fraction of a production process, usually np or p control charts are used for this purpose. However, in many practical situations, the binary variables are correlated but not easily perceived by practitioners. The aim of this article is to present the maximum likelihood and method of moment estimators of the correlation parameter ρ of an overdispersed binomial distribution. Inferential procedure is also introduced to test the null hypothesis H0: ρ = 0 x H1: ρ > 0. A Shewhart‐type control chart npρ and an Exponentiated Weighted Moving Average (EWMA)‐type control chart (EWMA npρ) are proposed to evaluate the nonconforming fraction when the binary variables are correlated. The traditional np chart is a particular case of the npρ control chart when ρ = 0. The misuse of control limits of np control in case of correlated binary variables will result a large number of false alarms. To have the same performance (in terms of average run length) of the traditional np control chart, the npρ control chart needs at least to double the sample size. Numerical example illustrates the proposal. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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B.P. Weaver M.S. Hamada A.G. Wilson J.E. Bakerman 《Quality and Reliability Engineering International》2017,33(8):2699-2709
Assurance test plans are chosen to manage consumer's and producer's risks. We develop methods for planning Bayesian assurance tests for degradation data, ie, on the basis of the degradation data collected in the test, a decision is made whether to accept or reject a product. Bayesian assurance tests incorporate prior knowledge in the planning stage and use this information to evaluate posterior consumer's and producer's risks. We consider prior knowledge that takes the form of related degradation data. Assurance test plans are then found that meet the specified requirements for consumer's and producer's risks. We illustrate the planning of such assurance tests with an example involving printhead migration data. We also investigate the impact of measurement error on these assurance test plans. 相似文献
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《Quality Engineering》2012,24(4):553-563
AbstractGroup and conditional sampling methods have been recently developed to apply in industrial environments. Based on the combination of two group and conditional schemes, this article introduces a group multiple dependent state sampling plan for a truncated life test when the lifetime of item follows the Weibull distribution. The proposed plan can be applied when the quality history of process is accessible and a multiple number of items are installed as a group in each tester. The proposed plan has merits which are illustrated via a comparative study over the existing group acceptance sampling plan. Furthermore, a real example is provided. 相似文献
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Roger L. Berger 《技术计量学》2013,55(4):295-300
The quality of a product might be determined by several parameters, each of which must meet certain standards before the product is acceptable. In this article, a method of determining whether all the parameters meet their respective standards is proposed. The method consists of testing each parameter individually and deciding that the product is acceptable only if each parameter passes its test. This simple method has some optimal properties including attaining exactly a prespecified consumer's risk and uniformly minimizing the producer's risk. These results are obtained from more general hypothesis-testing results concerning null hypotheses consisting of the unions of sets. 相似文献
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This article provides a methodology to combine overlapping stratified random samples and a simple random sample to estimate subpopulation proportions. That is, all the available data can be used to better estimate the quantities of interest. The methodology based on a Bayesian approach is illustrated with a synthetic data set. WinBUGS code that implements the combined analysis is also presented. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Pramote Charongrattanasakul Wimonmas Bamrungsetthapong Poom Kumam 《计算机、材料和连续体（英文）》2022,73(3):4611-4626
The design of a new adaptive version of the multiple dependent state (AMDS) sampling plan is presented based on the time truncated life test under the Weibull distribution. We achieved the proposed sampling plan by applying the concept of the double sampling plan and existing multiple dependent state sampling plans. A warning sign for acceptance number was proposed to increase the probability of current lot acceptance. The optimal plan parameters were determined simultaneously with nonlinear optimization problems under the producer’s risk and consumer’s risk. A simulation study was presented to support the proposed sampling plan. A comparison between the proposed and existing sampling plans, namely multiple dependent state (MDS) sampling plans and a modified multiple dependent state (MMDS) sampling plan, was considered under the average sampling number and operating characteristic curve values. In addition, the use of two real datasets demonstrated the practicality and usefulness of the proposed sampling plan. The results indicated that the proposed plan is more flexible and efficient in terms of the average sample number compared to the existing MDS and MMDS sampling plans. 相似文献
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To-Cheng Wang;Ming-Hung Shu; 《Quality and Reliability Engineering International》2024,40(4):1780-1794
Warranty is a standard and essential policy for today's products. The period and cost of warranty are majorly affected by the reliability of products. Therefore, validation and verification of product reliability are required to control warranty costs and sustain the brand reputation. In this paper, we propose a modified reliability acceptance sampling plan (MRASP) for product reliability validation. The operating characteristic function of the MRASP is derived by considering the accelerated time-to-failure data with Type-II censoring, which follows a Weibull distribution. To minimize the number of failures required for the accelerated life test and consider the sampling risk constraints, we constructed an optimization model to determine the optimal plan design of the proposed MRASP. Following the optimal plan design, practitioners can set the number of failures required in the accelerated life test to estimate the lifetime capability of the submitted lot and decide the lot disposition using the acceptance benchmark. In addition, the lifetime capability estimation can be used to infer the warranty return rate and warranty cost of the lot, which is valuable for practitioners to formulate the warranty budget. Finally, we illustrate a real-world case to demonstrate the practicality and applicability of the proposed method. 相似文献
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The burn-in test time is an important parameter of the complex batch processing machine scheduling problem. The omission of the loss of quality deviations in manufacturing generates a non-comprehensive and imperfect result in the optimisation of burn-in time, which hinders the identification of proactive and economical optimisation strategies to prevent infant failure in manufacturing. To solve this problem, this study visualises and quantifies for the first time the hidden loss caused by quality deviations in manufacturing and uses it as a newly added constraint to optimise the burn-in time. Firstly, a quality loss model composed of visible yield loss and warranty costs related to measurable but undetectable reliability vulnerabilities is defined. Secondly, the loss effects of growing defects are measured during the burn-in test, and the optimal burn-in time expressed by the proposed quality loss model is traded off between the additional burn-in cost and the decreased quality loss for an acceptable low infant failure rate. Finally, the effectiveness of the proposed optimisation approach is demonstrated using actual data from a control board with a high infant failure rate. Results show that the proposed method can systematically combine the fundamental loss of quality deviations in the optimisation of burn-in time, which supplements the commonly used optimality criteria, with the upstream loss of quality deviations in the form of manufacturing defects. 相似文献
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目的探索消费者对轿车内饰中仪表板总成造型及其设计风格的心理认知特性。方法邀请34位消费者对97款轿车仪表板造型进行相似性判断实验,以聚类分析、多维尺度分析方法处理实验数据,分别得到消费者对仪表板造型的认知分类和知觉图,并进行知觉图中造型特征分布与变化规律的定性分析。结论依据消费者造型相似性判断,将97款造型分为8个类别。97款轿车内饰仪表板造型有规律地分布在二维知觉图中,表明消费者对轿车内饰仪表板造型的心理认知空间具有两个明显的维度性,可将其归纳为整体造型特征维度以及功能性分区造型特征维度。前者反映在造型中整体面的分割、仪表板的总体比例、造型中边线曲直及其转接等设计特征方面;后者表现在中控台造型特征的差异上。此外,对于轿车内饰中方向盘、显示屏等功能性造型,并未在知觉图中发现其造型变化方面的明确分布特点。 相似文献
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In many situations, we want to accept or reject a population with small or finite population size. In this paper, we will describe Bayesian and non‐Bayesian approaches for the reliability demonstration test based on the samples from a finite population. The Bayesian method is an approach that combines prior experience with newer test data in the application of statistical tools for reliability quantification. When test time and/or sample quantity is limited, the Bayesian approach should be considered. In this paper, a non‐Bayesian reliability demonstration test is considered for both finite and large population cases. The Bayesian approach with ‘uniform’ prior distributions, Polya prior distributions, and sequential sampling is also presented. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献