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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: 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…

1723

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: 1 June 1943

H. Rissik

THE first part of this article, published in last month's issue of AIRCRAFT ENGINEERING, outlined the operation of the non‐statistical method of sampling inspection commonly met…

Abstract

THE first part of this article, published in last month's issue of AIRCRAFT ENGINEERING, outlined the operation of the non‐statistical method of sampling inspection commonly met with in purchasing specifications, and explained the inability of such a sampling clause to discriminate effectively between good and bad quality product. The present issue describes the practical applications of statistically designed sampling inspection procedures, giving adequate quality assurance wherever 100 per cent inspection of the product is either inapplicable or uneconomic.

Details

Aircraft Engineering and Aerospace Technology, vol. 15 no. 6
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 21 September 2011

Stephen Foerster

Behavioral researchers argue that although individuals often rely on heuristics or rules of thumb that reduce the complexity involved in predicting values, such heuristics can…

Abstract

Behavioral researchers argue that although individuals often rely on heuristics or rules of thumb that reduce the complexity involved in predicting values, such heuristics can lead to severe and systematic errors. I test this argument in an investment context by focusing on a simple heuristic whereby momentum traders are attracted to buying stocks that have recently doubled in price in anticipation of further gains. I show that such a strategy can lead to predictable disappointment for these investors and severe underperformance relative to the market (‐28% over a 4‐year period), whereas investors who avoid relying on this simple heuristic are likely to perform as expected, on average similar to the overall market. I also find that underperformance is more severe for stocks that have doubled faster. The “doubling” variable is a significant predictor of future price reversals in addition to past performance per se, as uncovered by the previous researchers.

Details

Review of Behavioural Finance, vol. 3 no. 2
Type: Research Article
ISSN: 1940-5979

Keywords

Article
Publication date: 1 August 2023

Rafaela Aparecida Mendonça Marques, Aline Cristina Maciel, Antonio Fernando Branco Costa and Kleber Roberto da Silva Santos

This study investigates the repetitive mixed sampling (MRS) plan based on the Cpk index that was proposed by Aslam et al. (2013a). They were the first to study the MRS plan, but…

Abstract

Purpose

This study investigates the repetitive mixed sampling (MRS) plan based on the Cpk index that was proposed by Aslam et al. (2013a). They were the first to study the MRS plan, but they did not pay attention to the fact that submitting to the variable inspection a sample that was first submitted to the attribute inspection, truncates the X observations. In addition, they did not work with an accurate expression to calculate the probabilities of the Cpk statistic.

Design/methodology/approach

The authors presented the results based on their original sampling plan through Monte Carlo simulation and defined the theoretical results of their plan when the sample submitted to the variable inspection is no longer the same one submitted to the attribute inspection.

Findings

The β risks of the optimum sampling plans presented by Aslam et al. (2013a) are pretty high, exceeding 46%, on average – this same problem was also observed in Saminathan and Mahalingam (2018), Balamurali (2020) and Balamurali et al. (2020), where the β risks of their proposed sampling plans are yet higher.

Originality/value

In terms of originality, the authors can declare the following. It is not a big deal to propose new sampling plans, if one does not know how to obtain their properties. The miscalculations of the sampling plans risks are dangerous; imagine the situation where the acceptance of bad lots exceeds 50% just because the sampling plan was incorrectly designed. Yes, it is a big deal to warn that this type of problem is arising in a growing number of papers. The authors of this study are the pioneers to discover that many studies focusing on the sampling plans need to be urgently revised.

Details

International Journal of Quality & Reliability Management, vol. 41 no. 2
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 18 December 2009

Marvin Rothwell, Eui Park and Daebeom Kim

The reduction of the time and resources spent inspecting product is critical to the success of Company L's continued resourcing efforts. The use of Mil‐Std and other sampling

1255

Abstract

The reduction of the time and resources spent inspecting product is critical to the success of Company L's continued resourcing efforts. The use of Mil‐Std and other sampling plans with acceptance numbers greater than zero usually results in increased inspection sizes and potential for controversy in inspection results between inspectors. The time and resources used to complete these outgoing inspections are directly related to the amount of product currently required to be inspected in order to determine the acceptance or rejection of a lot of finished goods. This paper proposes a new sampling policy that will allow Company L to reduce the size of outgoing inspections. The data used in the paper are from 2006 to 2007. It is a combination of Overseas Inspection reports from all suppliers as well as sales volumes for products sold to Company L's partner companies. There are currently over 80 suppliers that manufacture products for Company L. The major finding of this paper is that it is possible to reduce inspection size while still maintaining, or in most cases reducing, the risks associated with sample inspections. This will be accomplished by switching from the current Mil‐Std plan to a Zero acceptance number sampling plan.

Details

Asian Journal on Quality, vol. 10 no. 3
Type: Research Article
ISSN: 1598-2688

Keywords

Article
Publication date: 14 September 2023

Julia T. Thomas and Mahesh Kumar

The purpose of the paper is set to minimize the total cost of a manufacturing system when an acceptance sampling plan (ASP) is carried out in a fuzzy environment.

Abstract

Purpose

The purpose of the paper is set to minimize the total cost of a manufacturing system when an acceptance sampling plan (ASP) is carried out in a fuzzy environment.

Design/methodology/approach

A fuzzy acceptance sampling plan (FASP) is employed for the inspection of the batch of products and a fuzzy cost optimization problem is formulated.

Findings

The extent of uncertainty determines an interval for the total cost function with upper and lower bounds. The effect of variation in the ambiguity of the proportion of defectives in the probability of acceptance is determined.

Practical implications

The proposed model is specifically designed for production and supply units with ASP for attributes. Still, the proportion of defectives in the inspection process is fuzzy.

Originality/value

Fuzzy probability distribution is used to model an optimal inspection plan for a general supply chain. Economic design of supply chain under fuzzy proportion of defectives is discussed for the first time.

Details

International Journal of Quality & Reliability Management, vol. 41 no. 3
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 10 April 2007

P.S. Hui, L.T. Wong and K.W. Mui

The aim of this paper is to propose alternative sampling schemes for indoor air quality assessments in which a balance between the sampling time required and number of sampling

1531

Abstract

Purpose

The aim of this paper is to propose alternative sampling schemes for indoor air quality assessments in which a balance between the sampling time required and number of sampling points chosen is allowed.

Design/methodology/approach

CO2 was used as a reference to evaluate the existing and the proposed sampling schemes for average indoor pollutant concentration regarding the sampling time and sampling point density required and the probable errors induced at certain confidence levels of the measurement.

Findings

The results showed that increasing the number of sampling points would significantly reduce the corresponding sampling time required: at the same confidence level, doubling the sampling point density from 250 m2 to 500 m2 per measurement point would reduce the sampling time required from eight hours to three hours.

Research limitations/implications

The model parameters were determined from surveys for some typical offices in Hong Kong and therefore may require adaptation for use elsewhere.

Practical implications

A useful source of information in determining the number of sampling points chosen and the duration of the measurement needed according to the “acceptable” measurement uncertainty allowed.

Originality/value

Providing flexibility in IAQ assessment, the results would be useful to policymakers for making decisions on resources and manpower management for their respective sampling strategies while taking the uncertainties into account.

Details

Facilities, vol. 25 no. 5/6
Type: Research Article
ISSN: 0263-2772

Keywords

Article
Publication date: 13 August 2018

Hamed Hemmati Pourghashti, Malek Mohammad Ranjbar and Rahmat Madandoust

The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main…

Abstract

Purpose

The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main goals of this study is to compare the tensile and compressive strengths of recycled concrete samples.

Design/methodology/approach

Recycled concrete samples were made with variables such as aggregate type (natural stone and aggregate recycled concrete), different water-to-cement ratios and different treatment conditions in the first stage. In the next stage, the double punch test was performed on them, and finally the results obtained from experiments were analyzed and investigated.

Findings

According to the above tests, it was concluded that: first, according to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Second, upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. Third, upon investigating the results of tensile strength, it can be said that the Barcelona test results were closer to the direct tensile test results compared to the Brazilian test results. This indicates the higher viability of Barcelona’s test results. Fourth, the results obtained from the Barcelona tensile test for recycled concrete were closer to the results of the direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. Fifth, the effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. Sixth, the relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregates compared to recycled concrete. Seventh, the dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregates, but lesser of this dispersion was observed in the compressive strength.

Originality/value

According to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. On the basis on the results of the tensile strength, it can be said that the Barcelona test results were closer to the results of the direct tensile test compared to those of the Brazilian test. This indicates the higher viability of Barcelona’s test results. The results obtained from the Barcelona tensile test for recycled concrete were closer to the results of direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. The effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. The relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregate compared to recycled concrete. The dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregate, but lesser of this dispersion was observed in the compressive strength.

Details

International Journal of Structural Integrity, vol. 9 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

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