• Journal of Korean Society for Quality Management
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• v.28 no.2
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• pp.1-16
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• 2000

This paper considers the problem of determining the optimal process mean and screening specification limits of a surrogate variable associated with product quality under two-stage screening procedure. In two-stage screening, the surrogate variable is inspected first to decide whether an item should be accepted, rejected or additional observations should be taken. If additional observations are required, the performance variable of interest is then observed to classify the undecided items. Assuming that the performance variable and the surrogate variable are jointly normally distributed, the optimal process mean and the screening limits are obtained by maximizing the expected profit which includes selling price, production, reprocessing, inspection and penalty costs. A numerical example is presented and numerical studies are performed to compare the proposed two-stage screening procedure with single-stage screening procedures.

• Journal of Korean Society for Quality Management
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• v.36 no.4
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• pp.77-86
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• 2008

Due to the rapid growth in automated testing and manufacturing systems, screening inspection becomes very attractive. In this paper, we investigate the effects of limited capacity on screening inspection using a surrogate variable. The model is developed under the assumption that the reprocessed and nonreprocessed items are produced by the same manufacturing process and therefore their quality characteristics are independently and identically distributed. Profit models are constructed which involve four price/cost components; selling price, cost incurred by imperfect quality, reprocessing and quality inspection costs. Methods of finding the optimal screening limits are presented, and a numerical example is given. Sensitivity analyses are also performed to study the effect of a process standard deviation on this model.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.3
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• pp.336-341
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• 1999

The problem of jointly determining the optimum process mean and screening limits for each market is considered in situations where there are several markets with different price/cost structures. The quality characteristic is assumed to be a normal distribution with unknown mean and known variance. A quadratic loss function is utilized for developing the economic model. Methods of finding the optimum process mean and screening limits are presented and a numerical example is given.

• Journal of Korean Society for Quality Management
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• v.28 no.2
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• pp.161-175
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• 2000

The problem of jointly determining the optimum process mem and screening limits for each market is considered in situations where there are several markets with different price/cost structures. Two inspection procedures are considered; an inspection based on the quality characteristic of interest, and an inspection based on a surrogate variable which is highly correlated with the quality characteristic. The quality characteristic is assumed to be a normal distribution with unknown mean and known variance. A Taguchi's quadratic loss function is utilized for developing the economic model for determining the optimum process mean and screening limits. A numerical example is given.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.1
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• pp.17-36
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• 1996

An economic two-stage screening procedure is presented when both lower and upper specification limits are given on the performance variable. A screening variable which is highly correlated with the performance variable is used first to decide whether an item should be accepted, rejected, or undecided. The performance variable is then used to classify the undecided items. The two variables are assumed to be jointly normally distributed. A cost model is constructed on the basis of six cost components; inspection costs of screening and performance variables and costs caused by type I and type II misclassification errors related with lower and upper specification limits. Optimal cutoff values on the screening variable are determined so that the average outgoing quality exceeds a prespecified level. Solution methods are provided for both known-parameter and unknown-parameter cases.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.1
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• pp.1-7
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• 1999

This paper considers the problem of determining the optimum target values of the quality characteristic of interest Y and the screening limits of a surrogate variable X which is correlated with Y under two-stage screening procedure. In the two-stage screening procedure, X is measured first to decide whether an item should be accepted, rejected or additional observations should be taken. If it is difficult to decide on the result of measured value of X, Y is then observed to classify the undecided items. Assuming that Y and X are jointly normally distributed, a model is constructed which involves selling and reduced prices, production, inspection, and penalty costs. Methods of finding the optimum process mean and the screening limits are presented. A numerical example and analysis of the results are also presented.

• Journal of Korean Society for Quality Management
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• v.25 no.4
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• pp.57-70
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• 1997

Consider a production system where all manufactured products are screened through automatic inspection equipment. The products for which the measured value of quality characteristic is larger than the lower screening specification limit (SL) and smaller than the u, pp.r screeing specification limit(SU) are accepted. Those smaller than SL are reworked and those larger than SU are excluded from the process. Assuming that the quality characteristic is normally distributed with known variance, this paper suggests cost models which involve inspection cost, production cost, rework cost, exclusion cost and quality cost, and presents the methods of finding the optimal values of the screening specification limits and the process target. Numerical example is given to demonstrate the a, pp.icability of the cost models suggested in this paper.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.17 no.2
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• pp.39-47
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• 2017

Purpose: A sensitive gas chromatography mass spectrometry (GC-MS) method was developed for screening of fatty acid oxidation disorders. Methods: The assay utilized a simple protein precipitation with sulfosalicylic acid followed by tert-butyl dimethylsilyl (TBDMS) derivatization of hydroxyl functional group by N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA). Results: Calibration curves of spiked pooled plasma showed a linear relationship in the range of 0.01 ng -2 mg with correlation coefficient value greater than 0.98. Limits of detection (LOD) and limits of quantification (LOQ) were found in the range of 0.9-8.8 ng and 9-88 ng, respectively. Conclusion: The new developed method might be useful for a rapid, sensitive screening of inherited fatty acid oxidation disorders. In addition, the method expected to be one of the alternative method for screening newborns of metabolic disorders in the laboratories where expensive MS/MS is unavailable.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.365-368
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• 2006

The implementation of a screening procedure for removing non-conforming products has become a common practice especially in high-tech manufacturing industries. Screening procedures involve a measurement on the quality characteristic of interest since decisions regarding the conformance to specifications are usually made on the basis of the realization of measurement. A significant variability in measurement procedures may result in the misclassification of an outgoing product (that is, falsely accepting defectives or falsely rejecting conforming items), which may lead to wrong interpretation on product quality, It may thus be necessary to consider the impacts of misclassification errors due to measurement variability when designing screening procedures. Along this line, this article investigates the design of screening procedures based on the assessment of misclassification errors. The main objective is to determine the screening limits on measured values so that two types of misclassification errors may properly be compromised.

• Journal of Information Technology Applications and Management
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• v.27 no.4
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• pp.37-48
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• 2020

This research proposes how to enhance low customer satisfaction with health screening services caused by procedural complexity and limits of health screening. The purpose of this study is to identify sub-components of the service quality provided by general health examination centers. This is a qualitative analysis of in-depth interviews of providers and consumers of medical services. The data were primarily analyzed by affinity diagram, and the data were sorted and analyzed according to the criteria suggested by Donabedian's four components. Four types of quality factors and the health screening service quality components of 39 subordinate items were assessed. Components related to the use of IT facilities comprise a significant amount of the physical factors, and there are high demands for IT facilities among customers.