Search results

1 – 10 of over 74000
Article
Publication date: 21 June 2013

Wichai Chattinnawat

This research aims to investigate the differences in designing the zero acceptance number single sampling plans using the apparent fraction of nonconforming and the binomial…

Abstract

Purpose

This research aims to investigate the differences in designing the zero acceptance number single sampling plans using the apparent fraction of nonconforming and the binomial distribution against the exact convolute compound hypergeometric distribution when both types of inspection errors are present.

Design/methodology/approach

This research presents the derivation and uses the numerical study to compare the calculated probability of acceptance and the minimum sample size when using the present design concept of binomial distribution with true fraction of nonconforming replaced with the apparent one. Under the presences of inspection errors and zero acceptance number, the probability of acceptance is alternatively derived and presented in term of a function of the probability generating function. This research uses numerical method to determine the differences in the probability of acceptance. The computation of the minimum sample sizes are presented along with the numerical results and the comparison.

Findings

When the inspection errors are present, the probability of acceptance is extremely decreased even for 1 percent of inspection errors of Type I (rejecting good product) and Type II (accepting bad product). The binomial apparent nonconforming notions yields an over‐estimation of the probability of acceptance, comparing with the exact convolute compound hypergeometric notion under the zero acceptance single sampling plans especially at low fraction of nonconforming levels, the six sigma quality levels. The differences of the calculated probabilities of acceptance and the minimum sample sizes decrease as the inspection error of Type II increases given a fixed value of Type I error and consumer risk.

Originality/value

This research alternatively presents the mathematical derivation along with numerical study to assert the over‐estimation of the probability of acceptance and the minimum sample size if the existing methodology to design the zero acceptance number single sampling plans is used. This finding will help improve the sampling design strategy of the multistage production system.

Details

International Journal of Quality & Reliability Management, vol. 30 no. 6
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 1 May 1992

David H. Baillie

Selects one of Hamaker′s procedures for deriving a “σ” method (i.e. known process standard deviation) double sampling plan and exploits some of its properties to develop a system…

Abstract

Selects one of Hamaker′s procedures for deriving a “σ” method (i.e. known process standard deviation) double sampling plan and exploits some of its properties to develop a system of “s” method (i.e. unknown process standard deviation) double sampling plans by variables that match the system of single specification limit “s” method single sampling plans of the current edition of the international standard on sampling by variables. ISO 3951: 1989. The new system is presented in two forms, the second of which may also be used for combined double specification limits and multivariate acceptance sampling.

Details

International Journal of Quality & Reliability Management, vol. 9 no. 5
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 4 January 2013

Kandasamy Subramani and Venugopal Haridoss

The purpose of this paper is to present the single sampling attribute plan for given acceptance quality level (AQL) and limiting quality level (LQL) involving minimum sum of risks…

512

Abstract

Purpose

The purpose of this paper is to present the single sampling attribute plan for given acceptance quality level (AQL) and limiting quality level (LQL) involving minimum sum of risks using weighted Poisson distribution.

Design/methodology/approach

For the given AQL and LQL, sum of producer's and consumer's risks have been attained. Based on weighted Poisson distribution, the sum of these risks has been arrived at, along with the acceptance number and the rejection number. Also, the operating characteristic function for the single sampling attribute sampling plan, using weighted Poisson distribution, has been derived.

Findings

In the final inspection, the producer and the consumer represent the same party. So, the sum these two risks should be minimized. In this paper, the sum of risks has been tabulated using weighted Poisson distribution for different operating ratios. These tabulated values are comparatively less than the sum of risks derived using Poisson distribution.

Originality/value

The sampling plan presented in this paper is particularly useful for testing the quality of finished products in shop floor situations.

Details

International Journal of Quality & Reliability Management, vol. 30 no. 1
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 3 August 2010

Belmiro P.M. Duarte and Pedro M. Saraiva

This paper seeks to present an optimization‐based approach to design acceptance sampling plans by variables for controlling non‐conforming proportions in lots of items. Simple and…

Abstract

Purpose

This paper seeks to present an optimization‐based approach to design acceptance sampling plans by variables for controlling non‐conforming proportions in lots of items. Simple and double sampling plans with s known and unknown are addressed. Normal approximation distributions proposed by Wallis are employed to handle plans with s unknown. The approach stands on the minimization of the average sampling number (ASN) taking into account the constraints arising from the two point conditions on the operating characteristic (OC) curve. The resulting optimization problems fall under the class of mixed integer non‐linear programming (MINLP), and are solved employing GAMS. The results obtained strongly agree with classical acceptance sampling plans found in the literature, although outperforming them in some cases, and providing a general approach to address other cases.

Design/methodology/approach

The approach takes the form of formulation of the design of acceptance sampling plans by variables for non‐conforming proportions as optimization problems minimizing the ASN with the constraints being the acceptance probability at the controlled points of the OC curve, and subsequent solution of the mathematical programming problems arising with mathematical programming algorithms.

Findings

The results are in strong agreement with acceptance sampling plans available in the literature. The approach presented here outperforms the classical plans in some cases and its generality allows one to design other plans without the requirement of additional relations between the parameters and intensive enumerative algorithms.

Originality/value

The paper presents an optimization‐based approach to design robust acceptance sampling plans by variables for non‐conforming proportions that allows a general treatment and disregards the need for computational intensive enumerative‐based procedures.

Details

International Journal of Quality & Reliability Management, vol. 27 no. 7
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 5 September 2008

Belmiro P.M. Duarte and Pedro M. Saraiva

This purpose of this paper is to present an optimization‐based approach to support the design of attribute sampling plans for lot acceptance purposes, with the fraction of…

1725

Abstract

Purpose

This purpose of this paper is to present an optimization‐based approach to support the design of attribute sampling plans for lot acceptance purposes, with the fraction of non‐conforming items being modeled by a Poisson probability distribution function.

Design/methodology/approach

The paper approach stands upon the minimization of the error of the probability of acceptance equalities in the controlled points of the operating curve (OC) with respect to sample size and acceptance number. It was applied to simple and double sampling plans, including several combinations of quality levels required by the producer and the consumer. Formulation of the design of acceptance sampling plans as an optimization problem, having as a goal the minimization of the squared error at the controlled points of the OC curve, and its subsequent solution employing GAMS.

Findings

The results are in strong agreement with acceptance sampling plans available in the open literature. The papers approach in some scenarios outperforms classical sampling plans and allows one to identify the lack of feasible solutions.

Originality/value

An optimization‐based approach to support the design of acceptance sampling plans for attributes was conceived and tested. It allows for a general treatment of these problems, including the identification of a lack of feasible solutions, as well as making possible the determination of feasible alternatives by relaxing some model constraints.

Details

International Journal of Quality & Reliability Management, vol. 25 no. 8
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 28 November 2023

M. Sankara Narayanan, P. Jeyadurga and S. Balamurali

The purpose of this paper is to design a modified version of the double sampling plan to handle the inspection processes requiring a minimum sample size to assure the median life…

Abstract

Purpose

The purpose of this paper is to design a modified version of the double sampling plan to handle the inspection processes requiring a minimum sample size to assure the median life for the products under the new Weibull–Pareto distribution. The economic design of the proposed plan is also considered to assure the product's lifetime with minimum cost.

Design/methodology/approach

The authors have developed an optimization model for obtaining the required plan parameters by solving simultaneously two non-linear inequalities and such inequalities have been formed based on the two points on the operating characteristic curve approach.

Findings

The results show that the average sample number, average total inspection and total inspection cost under the proposed plan are smaller than the same of a single sampling plan. This means that the proposed plan will be more efficient than a single sampling plan in reducing inspection effort and cost while providing the desired protection.

Originality/value

The proposed modified double sampling plan designed to assure the median life of the products under the new Weibull–Pareto distribution is not available in the literature. The proposed plan will be very useful in assuring the product median lifetime with minimum sample size as well as minimum cost in all the manufacturing industries.

Details

International Journal of Quality & Reliability Management, vol. 41 no. 5
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 1 March 1993

V. Soundararajan and S. Devaraj Arumainayagam

Presents a compact table yielding the parameters of a single sampling scheme. The table is compatible with the structure of MIL‐STD‐105D and the switching procedure incorporated…

Abstract

Presents a compact table yielding the parameters of a single sampling scheme. The table is compatible with the structure of MIL‐STD‐105D and the switching procedure incorporated in this scheme is relatively simpler than that of MIL‐STD‐105D. The basis for the construction of the table is given. Methods are given for the selection of a scheme having either acceptable quality level, limiting quality level, indifference quality level or average outgoing quality limit as a function of lot size.

Details

International Journal of Quality & Reliability Management, vol. 10 no. 3
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 12 October 2021

Waqar Hafeez and Nazrina Aziz

This paper introduces a Bayesian two-sided group chain sampling plan (BT-SGChSP) by using binomial distribution to estimate the average proportion of defectives. In this Bayesian…

Abstract

Purpose

This paper introduces a Bayesian two-sided group chain sampling plan (BT-SGChSP) by using binomial distribution to estimate the average proportion of defectives. In this Bayesian approach, beta distribution is used as a suitable prior of binomial distribution. The proposed plan considers both consumer's and producer's risks. Currently, group chain sampling plans only consider the consumer's risk and do not account for the producer's risk. All existing plans are used to estimate only a single point, but this plan gives a quality region for the pre-specified values of different design parameters. In other words, instead of point wise description for the designing of sampling plan based on a range of quality by involving a novel approach called quality region.

Design/methodology/approach

The methodology is based on five phases, which are (1) operating procedure, (2) derivation of the probability of lot acceptance, (3) constructing plans for given acceptable quality level (AQL) and limiting quality level (LQL), (4) construction of quality intervals for BT-SGChSP and (5) selection of the sampling plans.

Findings

The findings show that the operating characteristic (OC) curve of BT-SGChSP is more ideal than the existing Bayesian group chain sampling plan because the quality regions for BT-SGChSP give less proportion of defectives for same consumer's and producer's risks.

Research limitations/implications

There are four limitations in this study: first is the use of binomial distribution when deriving the probability of lot acceptance. Alternatively, it can be derived by using distributions such as Poisson, weighted Poisson and weighted binomial. The second is that beta distribution is used as prior distribution. Otherwise, different prior distributions can be used like: Rayleigh, exponential and generalized exponential. The third is that we adopt mean as a quality parameter, whereas median and other quintiles can be used. Forth, this paper considers probabilistic quality region (PQR) and indifference quality region (IQR).

Practical implications

The proposed plan is an alternative of traditional group chain sampling plans that are based on only current lot information. This plan considers current lot information with preceding and succeeding lot and also considers prior information of the product.

Originality/value

This paper first time uses a tight (three acceptance criteria) and introduces a BT-SGChSP to find quality regions for both producer's and consumer's risk.

Details

International Journal of Quality & Reliability Management, vol. 39 no. 10
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 1 February 1991

K. Govindaraju and K. Subramani

A table and a procedure are given for finding the singlesampling quick switching system for which the sum of producer′s and consumer′s risks is minimum for specified Acceptable…

Abstract

A table and a procedure are given for finding the singlesampling quick switching system for which the sum of producer′s and consumer′s risks is minimum for specified Acceptable Quality Level and Limiting Quality Level.

Details

International Journal of Quality & Reliability Management, vol. 8 no. 2
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 1 March 1990

V. Soundararajan and R. Vijayaraghavan

The readily available acceptance number value is revised in the form of three tables. From these tables it is possible to determine single or chain sampling inspection plans when…

Abstract

The readily available acceptance number value is revised in the form of three tables. From these tables it is possible to determine single or chain sampling inspection plans when the sample size is fixed. These tables replace the large number of existing tables in use.

Details

International Journal of Quality & Reliability Management, vol. 7 no. 3
Type: Research Article
ISSN: 0265-671X

Keywords

1 – 10 of over 74000