• Industrial Engineering and Management Systems
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• v.11 no.4
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• pp.390-396
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• 2012

The present paper extends the idea of tightened-normal-tightened sampling scheme to group acceptance sampling plans under the time truncated life tests. We consider three famous distributions that are widely used in the area of reliability such as the generalized exponential distribution, the Weibull distribution, and the Birnbaum-Saunders distribution in the proposed sampling plan. The plan parameters are determined such that the producer's risk and the consumer's risk are satisfied at the specified median life. Extensive tables showing plan parameters are provided at various values of the experiment time and the consumer's risk for each of three distributions for the practical use. Some examples are given to illustrate the procedure of the proposed plan.

• Journal of the Korean Data and Information Science Society
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• v.14 no.4
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• pp.915-927
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• 2003

This paper is the generalization of the modified two-level skip-lot sampling plan(MTSkSP1) to n-level. The general formulas of the operating characteristic(OC) function, average sample number(ASN) and average outgoing quality(AOQ) for the plan are derived using Markov chain properties. The operating characteristic curves, average sample numbers and average outgoing qualities of a reference plan, modified two-level, three-level and five-level skip-lot sampling plans are compared.

• Journal of Korean Institute of Industrial Engineers
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• v.5 no.1
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• pp.7-17
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• 1979

A procedure for constructing a double sampling plan with zero acceptance number for the first sample whose combined sample size does nat exceed that of the given single or double sampling plan is studied. Using this procedure a double sampling system is proposed that can be used in place of MIL-STD-105D system when the quality history is good, and its composite quality characteristics are tabulated and compared with those of MIL-STD-105D system. The study reveals that composite ASN's of the proposed double sampling system are considerably smaller than those of corresponding MIL-STD-105D system with no appreciable changes in other composite quality characteristics. The procedure is also applied to K SA 3102 plans with similar results. A cost model that can be used in comparing a given single sampling plan with the proposed double sampling plan is also developed.

• Korean journal of applied entomology
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• v.54 no.3
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• pp.159-167
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• 2015

In order to establish B. tabaci control in paprika greenhouses a fixed-precision-level sampling plan was developed. The sampling plan consisted of spatial distribution analysis, a sampling stop line, and decision making. Sampling was conducted simultaneously in two independent greenhouses (GH 1, GH 2). GH 1 and 2 were surveyed every week for 22 consecutive weeks, using 19 sampling locations in GH 1 and 9 sampling locations in GH 2. The plant in both greenhouses were divided into top (180-220 cm from the ground), middle (80-120 cm from the ground) and bottom (30-70 cm from the ground) sections and B. tabaci adults and pupae were observed on three paprika leaves at each position and recorded separately. GH 2 data were used to validate the fixed-precision sampling plan, which was developed using GH 1 data. In this study, spatial distribution analysis was performed using Taylor's power law with the pooled data of the top and bottom position (B. tabaci adults), and the middle and bottom positions (B. tabaci pupae), based on a 1-leaf sampling unit. Decision making was undertaken using the maximum of action threshold in accordance with previously published method, and the value was decided by the price of the plants. Using the results obtained in the greenhouse, simulated validation of the developed sampling plan by RVSP (Resampling Validation for Sampling Plan) indicated a reasonable level of precision.

• International Journal of Reliability and Applications
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• v.6 no.1
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• pp.31-39
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• 2005

An economic life test sampling plan for products with exponential lifetime distribution is developed. To reduce test time, a test plan with curtailed Type II censoring is considered. A cost model is constructed which involves three cost components; test cost, accept cost, and reject cost. Determination of optimal plan minimizing the expected average cost per lot is discussed with a constraint related to consumer's risk. Some numerical examples are provided.

• Journal of the Korean Data and Information Science Society
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• v.19 no.3
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• pp.811-818
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• 2008

This paper is the generalization of the modified two-level skip-lot sampling plan(MTSkSP2) to n-level. The general formulas of the operating characteristic(OC) function, average sample number(ASN) and average outgoing quality(AOQ) for the plan are derived using Markov chain properties.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.3
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• pp.205-212
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• 2004

This paper proposes the variables repetitive group sampling plan where the quality characteristic following normal distribution has upper or lower specification limit. The problem is formulated as a non-linear programming problem where the objective function to minimize is the average sample number and the constraints are related to lot acceptance probabilities at acceptable quality level (AQL) and limiting quality level (LQL) under the operating characteristic curve. Sampling plan tables are constructed for the selection of parameters indexed by AQL and LQL in the cases of known standard deviation and unknown standard deviation. It is shown that the proposed sampling plan significantly reduces the average sample number as compared with the single or the double sampling plan.

• Journal of Korean Society for Quality Management
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• v.11 no.1
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• pp.18-23
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• 1983

Continuous sampling plans CSP-1(i,f)'s with which AOQL is guaranteed, can be applied to the cases in need of effective sampling without stopping the process or dividing batches during production. But the plans that can guarantee the same AOQL value are too many. Therefore we have to select one plan among them. There may be a lot of ways to choose it. This paper connects with various sampling costs, the concept to try to detect the shift of process average under fractional inspection in CSP-1,to find a minimum cost sampling plan among several CSP-1 sampling plan alternatives (i, f)'s with the same AOQL value.

• Industrial Engineering and Management Systems
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• v.15 no.1
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• pp.41-48
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• 2016

In this manuscript, a modified single sampling plan is proposed for the inspection of products in which the nonconforming items can be classified in to two categories namely critical and non-critical; and explained with the help of industrial example. The operating procedure of this plan is also proposed and the performance measures such as the probability of acceptance, average sample number, average total inspection and average out going quality are also derived. The optimal parameters are determined which will have minimum sample size. The efficiency of the proposed plan is also discussed over the conventional single sampling plan. The extensive tables for selecting a modified single sampling plan based on AQL and LQL are provided for both Binomial and Poisson distributions and explained with the help of industrial data.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1183-1189
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• 2008

The general formulas of the operating characteristic(OC) function, average sample number(ASN) and average outgoing quality(AOQ) for the modified n-level skip-lot sampling plan(MMSkSP2) were derived using Markov chain properties by Cho(2008). In this paper, the OC curve, ASN and AOQ of a reference plan, modified two-level, three-level and five-level skip-lot sampling plans are compared.