Continuous Sampling Plans Research Articles

Enhancing quality in Lot reception: A comparative analysis of innovative attribute acceptance sampling plans

Purpose: This study aims to enhance production quality by applying Quality Control (QC) principles through acceptance sampling, specifically analyzing the efficacy of attribute acceptance sampling plans in final lot receptions.Design/methodology/approach: Through a comprehensive review and critical evaluation of various sampling methodologies found in literature, this paper assesses their efficiency under distinct administrative and operational conditions. It emphasizes the comparison of different attribute acceptance sampling plans by examining variations in parameters and key performance indicators, such as Average Outgoing Quality (AOQ) and inspection time allocation percentage. Furthermore, it proposes a model for Continuous Sampling Plans (CSP) to evaluate these plans' performance in response to operational characteristic variations.Findings: The analysis reveals that the selected methodologies significantly aid in decision-making processes for lot acceptance, utilizing non-conforming rates depicted by the Average Quality Level (AQL). This provides a robust framework for improving Quality Control strategies, demonstrating the potential of these methodologies to optimize production quality through strategic lot acceptance.Practical implications: This paper outlines a practical approach for industry practitioners to enhance decision-making in lot acceptance, offering a method to balance quality control with operational efficiency effectively.Originality/value: By comparing a wide range of attribute acceptance sampling plans and introducing a novel CSP model, this research contributes valuable insights into the optimization of QC strategies. It offers a unique perspective on enhancing production quality, marking a significant advancement in the field of Quality Control and management.

Optimum specification limit coefficient setting based on the smaller-the-better quality characteristics

In this work, the authors propose the application of type I continuous sampling plan (CSP-1 plan) with expected inspection cost, expected replacement cost, expected warranty cost, expected quality loss for conforming product, and expected quality loss for nonconforming product per item. The quality characteristics of product is considered as the normal distribution with smaller-the-better characteristics. The quality loss function of product addresses the quadratic quality loss function. The CSP-1 plan is applied in the process control. The optimal combination of parameters is obtained from the minimum expected total cost per item produced under the specified average outgoing quality limit (AOQL) protection. One needs to have the optimal clearance number, sampling frequency, and specification limit coefficient.

Optimum specification limit setting under the larger-the-better quality characteristics

In this paper, the optimal clearance number and sampling frequency of type I continuous sampling plan (CSP-1 plan) and specification limit coefficient of product are determined with the minimum expected total cost per item under the specified average outgoing quality limit (AOQL) protection. The expected total cost per item includes the expected inspection cost, the expected replacement cost, the expected warranty cost, the expected quality loss for conforming product, and the expected quality loss for non-conforming product per item. The quality characteristic of product is considered as the normal distribution with larger-the-better characteristics. The quality loss function of product addresses the quadratic quality loss function. The sensitivity analysis of numerical example will be provided for illustration.

Quality control for production and shipment process of product

In this article, the authors propose the integrated application of type I continuous sampling plan (CSP-1 plan) and Dodge-Romig rectifying inspection plan with quality loss and product cost. The normal quality characteristic, nominal-the-best, and asymmetric quadratic quality loss function of product are considered. The CSP-1 plan is firstly applied in the process control. Then Dodge-Romig rectifying inspection plan is applied in the product improvement. The optimal combination of parameters of CSP-1 plan and asymmetric specification limit coefficients are obtained under the specified average outgoing quality limit (AOQL) protection. The optimal combination of parameters of Dodge-Romig rectifying inspection plan and quality investment are determined under the specified consumer’s risk. Finally, the sensitivity analysis of numerical example will be provided for illustration.

The Effect of Pender’s Health Promotion Model-based Education on the Physical Activity among Pregnant Women

Background and Purpose: The positive effects of physical activity during pregnancy have been completely recognized. However, given the lack of required knowledge and information, most of the pregnant women are inactive, and providing an educational program is thus of high significance for pregnant mothers. Given the multifactorial nature of physical activity, being affected by personal, interpersonal, environmental, and social factors, Pender’s health promotion model has been applied for designing the required intervention. The present study was thus designed and conducted to investigate the effect of an educational intervention based on Pender’s health promotion model on the physical activity of pregnant women.Method: The present study is a quasi-experimental one with a control group conducted at four Comprehensive Health Service Centers (both urban and suburban) in Sanandaj in 2020. Applying a random-stratified sampling method, two centers were dedicated to the control group and two centers were dedicated for the intervention group. With a continuous sampling plan, based on the inclusion exclusion criteria, as many as 88 pregnant women referring to the health service centers were selected and entered into the present study in two groups of intervention and control (each group consists of 44 participants). The control group received the regular care and training and the intervention group was provided with an education program based on Pender’s Health Promotion Model in five sixty-to-ninetyminute sessions with different methods and materials includingbrainstorming, lectures, group discussions, questions and answers, showing movies, and providing educational booklets and brochures distributed among women.The data collection tools include demographic questionnaires and the Pregnancy Physical Activity Questionnair by Chasan-Taber et al. For investigating the effect of the intervention, the questionnaires were completed 6 weeks after the end of the intervention for both intervention and control groups. The data were analyzed by using SPSS-25 as well as Chi-squared test, Fisher’s Exact Test, independent T-test, and paired t-test.Findings: Before initiating the educational intervention, there was no significant difference between the groups in terms of demographic and physical activity scores.But after the educational intervention, there was a statistically significant difference in the mean of total physical activity between the intervention and control groups(P<0.001).Conclusion: The present study confirms the effectiveness of an educational intervention based on Pender’s Health Promotion Model on promoting the pregnant women’s physical activity. Given the findings of the present study, it is thus recommended to apply Pender’s Health Promotion Model as a framework for designing the educational intervention to promote the physical activity among women

The Continuous Sampling Plan for Two Production Lines: The CSP-2L

This paper presents the CSP-2L continuous sampling plan, which is designed for product inspectionon two independent production lines at the same time. The purpose of the CSP-2L is to improve the CSP-1-2Lin order to reduce the number of defective products that have passed without being inspected during thetemporary inspection stop, so the quality of the products is better. Therefore, if the manufacturer who uses theCSP-2L plan to inspect the production lines then resulting in higher quality of the products than the CSP-1-2L.This presentation includes the product inspection procedures and the formulas for performance measures suchas average total fraction inspected (ATFI), average total outgoing quality (ATOQ), and average total outgoingquality limit (ATOQL) which are carried out using a Markov chain. The formulas for performance measures ofthe CSP-2L have been tested to be accurate. When defined, the probability of a unit produced by the processbeing nonconforming of line 1 and line 2 are equal (p1 = p2 = p = 0.005, 0.015 and 0.035), the clearance numberof line 1 and line 2 are equal (i1 = i2 = 10, 20, 30, 40 and 50), the sampling fraction of line 1 and line 2 are equal(f1 = f2 =12and13) and the number of units to be found when inspection of line 1 and line 2 are in the phaseof sampling inspection at the same time (m = i1 and 2i1). Moreover, the ATOQ values from the CSP-2L and theCSP-1-2L plans were compared. The results showed that, the formulas for performance measures are accurateand in the case of p, the levels are low and moderate, the ATOQ of the CSP-2L are less than those of theCSP-1-2L in all cases. But in the case of p is at a high level, the ATOQ of the CSP-2L is less than those of theCSP-1-2L for some cases of i.

A variable-type skip-lot sampling plan for products with a unilateral specification limit

Acceptance sampling plans are practical quality management tools for lot sentencing. The rapid advancement of manufacturing technologies has reduced the defective rate substantially, and as a result, variables sampling plans with process capability indices (PCIs) have been adopted widely so that the required sample size can be decreased. Skip-lot sampling plan (SkSP), which evolved from the continuous sampling plan type-1, is applicable to bulk materials or products manufactured in successive batches or lots. It requires a smaller fraction of lots being examined, and the cost of inspection thus can be reduced. Hence, this paper consolidates the advantages of PCIs and SkSP, and proposes a skip-lot sampling plan of type-2, called SkSP-2, based on the one-sided PCIs for products with a unilateral specification limit. The proposed plan uses the exact sampling distribution of the estimators to develop a mathematical model for determining plan parameters, and the research prepares tables of plan parameters under different combinations of quality requirements and risk levels for quick reference in real applications. In addition, the results are compared with a conventional sampling plan to examine the contribution of the approach, and extensions to two types of SkSP are also presented. Finally, a graphical user interface is constructed to facilitate data input, criteria calculation and decision-making in practice.

Genetic forms and pathophysiology of essential arterial hypertension in minor indigenous peoples of Russia

BackgroundTo study the genetic forms and pathophysiology of arterial hypertension by evaluating plasma renin activity in the Shors, minor indigenous peoples inhabiting the south of Western Siberia.MethodsA single-stage study of indigenous (the Shors) and non-indigenous peoples living in the villages of Gornaya Shoria of the Kemerovo region in the south of Western Siberia was conducted in the period from 2013 to 2017. One thousand four hundred nine adults (901 Shors and 508 non-indigenous inhabitants) were recruited in the study using a continuous sampling plan. Arterial blood pressure was measured according to 2018 ESC/ESH guidelines for the management of arterial hypertension. All the respondents underwent clinical and instrumental examination. Plasma renin activity was determined by enzyme-linked immunoassay with the BRG kits (Germany). Polymorphisms of ACE (I/D, rs 4340), АGT (c.803 T > C, rs699), AGTR1 (А1166С, rs5186), ADRB1 (с.145A > G, Ser49Gly, rs1801252) and ADRA2B (I/D, rs 28,365,031) genes were tested using polymerase chain reaction.ResultsRenin-dependent hypertensive patients prevailed in both ethnic groups (65.6% in the indigenous group vs. 89.8% in the non-indigenous group, p = 0.001). Prevalence of a volume-dependent AH was low in both groups (34.4% in the indigenous group vs. 10.2% in the non-indigenous group, р = 0.001). The D/D and Т/Т genotypes of the АСЕ [OR = 6.97; 95% CI (1.07–55.58)] and AGT [OR = 3.53; 95% CI (1.02–12.91)] genes were associated with the renin-dependent AH in the Shors. The C/C genotype of AGTR1 gene was found to predispose to the volume-dependent AH [OR = 5.25; 95% CI (1.03–27.89)]. The C/C genotype of AGTR1 gene was associated with moderate or high renin levels suggesting essential AH in the non-indigenous group [OR = 5.00; 95% CI (1.21–22.30), р = 0.029].ConclusionAn in-depth understanding of AH pathophysiology and its genetic forms ensures the optimal choice of blood pressure-lowering treatment and optimizes AH control.

MATLAB Program for Simulating the Performance Measures of Continuous Sampling Plans

MATLAB Program for Simulating the Performance Measures of Continuous Sampling Plans

On the modes of the negative binomial distribution of order k, type I

Upper and lower bounds are derived for the modes of the negative binomial distribution of order k, type I, with parameter vector (r, p). The bounds are employed to establish an explicit formula for the modes in terms of k and r when p equals to 0.5. It is also shown that the mode is k when r equals 1. For computational purposes, two efficient algorithms are developed. The first evaluates the modes and the second simulates values of the distribution. An application connected to continuous sampling plans is discussed. Numerical examples illustrate further the results of the article.

Optimal Scheme for Process Quality and Cost Control by Integrating a Continuous Sampling Plan and the Process Yield Index

The single level continuous sampling plan (CSP-1) is an in-line process control tool that has been commonly adopted in various manufacturing industries. However, CSP-1 is designed for only satisfying the quality constraint. At the same time, CSP-1 has disadvantages with the high probabilities of both Type I and Type II errors due to its inherent deficiency coming from the operating procedure. In this work, an optimal scheme for process quality and cost control is proposed to monitor the process cost and improve the process quality. The CSP-1 and the process yield index (Spk) are integrated in the present scheme, which work independently and complementarily. The four parameters (clearance number, inspecting fraction, sample size, and critical value) are designed in the proposed scheme under simultaneously considering the quality and cost constraints. The sole feasible inspection scheme in CSP-1 under the two constraints is found and used for controlling the process quality. The probabilities of Type I and Type II errors are concurrently controlled at the stipulated level with the risk control scheme, which is constructed with two nonlinear inequation based on the accurate distribution of the index Spk. A case study is illustrated to validate the effectiveness and practicality of the proposed scheme.

Designing of Modified Tightened 3 Levels Continuous Sampling Plan Indexed through Maximum Allowable Average Outgoing Quality

The International Scientific Research Organization for Science, Engineering and Technology (ISROSET) is a Non-Profit Organization; The ISROSET is dedicated to improvement in academic sectors of Science (Chemistry, Bio-chemistry, Zoology, Botany, Biotechnology, Pharmaceutical Science, Bioscience, Bioinformatics, Biometrics, Biostatistics, Microbiology, Environmental Management, Medical Science, Forensic Science, Home Science, Library Science, Material Science Military Science, Physical Science, Physical Education Science, Educational Science, Fisheries, seed technology, Agriculture, Forestry Science, Mathematics, Physics, Statistics and Geology/Earth Science), Computer Science, Engineering and Information Technology, Commerce, Management, Economics Sociology and Social Science.

Optimal CSP-1 boundary scheme based on the estimator of the proportion of conformance for specified in-control process

ABSTRACTSingle-level continuous sampling plan (CSP-1), called contour scheme, is constructed on the average outgoing quality limit () contour. However, for specified in-control process the boundary of feasible continuous sampling scheme is not established in CSP-1. The optimal CSP-1 boundary scheme is established based on the estimator of the proportion of conformance for specified in-control process. The parameters of the boundary scheme are determined by the set of equations constructed with the boundary identical equation and contour identical equation, which will guarantee that the proposed scheme is simultaneously both boundary scheme and contour scheme. The behaviour of the established boundary scheme is discussed and compared with the contour scheme. The optimal CSP-1 boundary scheme can quantitatively control the outgoing quality and tighten the inspection whether the process quality fluctuates towards the deteriorated or the improved direction. For practitioners’ convenience, three tables of the boundary scheme parameters under three quality requirements and three confidence levels are provided. The operating procedure is also presented. A real example is given to verify the effectiveness and feasibility of the proposed boundary scheme.

Short-Run Contexts and Imperfect Testing for Continuous Sampling Plans

Continuous sampling plans are used to ensure a high level of quality for items produced in long-run contexts. The basic idea of these plans is to alternate between 100% inspection and a reduced rate of inspection frequency. Any inspected item that is found to be defective is replaced with a non-defective item. Because not all items are inspected, some defective items will escape to the customer. Analytical formulas have been developed that measure both the customer perceived quality and also the level of inspection effort. The analysis of continuous sampling plans does not apply to short-run contexts, where only a finite-size batch of items is to be produced. In this paper, a simulation algorithm is designed and implemented to analyze the customer perceived quality and the level of inspection effort for short-run contexts. A parameter representing the effectiveness of the test used during inspection is introduced to the analysis, and an analytical approximation is discussed. An application of the simulation algorithm that helped answer questions for the U.S. Navy is discussed.

Statistical Methods in Assembly Quality Management of Multi-Element Products on Automatic Rotor Lines

To control the assembly quality of multi-element mass-produced products on automatic rotor lines, control methods with operational feedback are required. However, due to possible failures in the operation of the devices and systems of automatic rotor line, there is always a real probability of getting defective (incomplete) products into the output process stream. Therefore, a continuous sampling control of the products completeness, based on the use of statistical methods, remains an important element in managing the quality of assembly of multi-element mass products on automatic rotor lines. The feature of continuous sampling control of the multi-element products completeness in the assembly process is its breaking sort, which excludes the possibility of returning component parts after sampling control to the process stream and leads to a decrease in the actual productivity of the assembly equipment. Therefore, the use of statistical procedures for continuous sampling control of the multi-element products completeness when assembled on automatic rotor lines requires the use of such sampling plans that ensure a minimum size of control samples. Comparison of the values of the limit of the average output defect level for the continuous sampling plan (CSP) and for the automated continuous sampling plan (ACSP) shows the possibility of providing lower limit values for the average output defects level using the ACSP-1. Also, the average sample size when using the ACSP-1 plan is less than when using the CSP-1 plan. Thus, the application of statistical methods in the assembly quality management of multi-element products on automatic rotor lines, involving the use of proposed plans and methods for continuous selective control, will allow to automating sampling control procedures and the required level of quality of assembled products while minimizing sample size.

Evaluation of Continuous Sampling Plan (CSP-5) Parameters Using GERT Technique and MATLAB

Abstract In this paper, we have designed the Continuous sampling plan (CSP-5) plan using GERT analysis and the software package MATLAB 2007b. The formula for finding the performance parameters such as AOQ, E(I) and the parameters i and f are found out by GERT technique and developing program for the construction of table values and plotting graph using MATLAB.

Performance measures of single–level continuous sampling plans for short production runs

Performance measures of single–level continuous sampling plans for short production runs

Bias-Corrected Estimation in Continuous Sampling Plans.

Continuous sampling plans (CSPs) are algorithms used for monitoring and maintaining the quality of a production line. Although considerable work has been done on the development of CSPs, to our knowledge, there has been no corresponding effort in developing estimators with good statistical properties for data arising from a CSP inspection process. For example, information about the failure rate of the process will affect the management of the process, both in terms of selecting appropriate CSP parameters to keep the failure rate after inspection at a suitable level, and in terms of policy, for example, whether the process should be completely inspected, or shut down. The motivation for this exercise was developing sampling protocols for Australia's Department of Agriculture and Water Resources for monitoring the biosecurity compliance of incoming goods at international borders. In this study, we show that maximum likelihood estimation of the failure rate under a sampling scheme can be biased depending on when estimation is performed, and we provide explicit expressions for the main contribution of the bias under various CSPs. We then construct bias-corrected estimators and confidence intervals, and evaluate their performance in a numerical study.

Construction and selection of continuous sampling plan of type (CSP-T) indexed through maximum allowable average outgoing quality

In this paper, we have introduced a novel designing and selection procedure of continuous sampling plan (CSP-T) indexed through Maximum Allowable Average Outgoing Quality (MAAOQ). Expressions for performance measures such as Operating Characteristic function and MAAOQ function are derived in this paper. The association of Average Outgoing Quality Level (AOQL), Maximum Allowable Percent Defective (MAPD) and MAAOQ in CSP-T are discussed. Comparisons between various CSPs plans are given. Tables and figures are constructed for easy selection of plan parameters.

Determination of Skip Lot Sampling Plan with Single Sampling Plan as Reference Plan under the conditions of Intervened Poisson Distribution

Skip lot sampling plans (SkSP) were developed by implementing the concepts of Continuous sampling plans (CSP) to inspect the raw materials bought regularly from a common source. Skip lot sampling plans are considered to be time and cost effective sampling plans so; it is most widely used in industries to inspect the series of lots. In SkSP, the lots are inspected using standard sampling plans as reference plan. This article presents a design for skip lot sampling plans of type SkSP-2 with single sampling plan (SSP) under the conditions of Intervened Poisson distribution (IPD) as reference plan. Further, the selection of proposed plan indexed through acceptable quality limit and limiting quality limit are presented.