• Communications for Statistical Applications and Methods
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• 제26권2호
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• pp.163-173
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• 2019

Simon's two-stage designs are frequently used in phase II single-arm trials for efficacy studies. A concern of safety studies is too many patients who experience an adverse event. We show that Simon's two-stage designs for efficacy studies can be similarly used to design a two-stage safety study by modifying some of the design parameters. Given the type I and II error rates and the proportion of adverse events experienced in the first stage cohort, we prescribe a procedure whether to terminate the trial or proceed with a stage 2 trial by recruiting additional patients. We study the relationship between a two-stage design with a safety endpoint and an efficacy endpoint as well as use simulation studies to ascertain their properties. We provide a real-life application and a free R package gen2stage to facilitate direct use of two-stage designs in a safety study.

• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2196-2207
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• 2017

This paper presents a two-stage market auction model in a pool-based electricity market, which explicitly takes into account the system network security. The security network-constrained market auction model considers the use of corrective control to yield economically efficient actions in the post-contingency state, while ensuring a certain security level. Under this framework, the proposed model shows not only for quantifying the correlation between secure system operation and efficient market operation, but also for providing transparent information on the pricing system security for market participants. The two-stage market auction procedure is formulated using Benders decomposition (BD). In the first stage, the market participants bid in the market for maximizing their profit, and the independent system operator (ISO) clears the market based on social welfare maximization. System network constraints incorporating post-contingency control actions are described in the second stage of the market auction procedure. The market solutions, along with the BD, yield nodal spot prices (NSPs) and nodal congestion prices (NCPs) as byproducts of the proposed two-stage market auction model. Two benchmark systems are used to test and demonstrate the effectiveness of the proposed model.

• Journal of the Korean Statistical Society
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• 제21권1호
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• pp.27-34
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• 1992

This paper provides a method of obtaining a lower bound on the probability of correct selection for a two-stage selection procedure. The resulting lower bound sharpens that by Tamhane and Bechhofer (1979) for the normal means problem with a common known variance. The design constants associated with the lower bound are computed and the results of the performance comparisons are given.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.777-786
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• 2007

This paper presents a modified simulated annealing algorithm to optimize linear scheduling projects with multiple resource constraints and its effectiveness is verified with a proposed problem. A two-stage solution-finding procedure is used to model the problem. Then the simulated annealing and the modified simulated annealing are compared in the same condition. The comparison results and the reasons of improvement by the modified simulated annealing are presented at the end.

• 산업경영시스템학회지
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• 제16권27호
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• pp.113-119
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• 1993

The purpose of this study is to develop a analytic procedure of the alternatives for the FMS that consist of high-priced facilities. A procedure to analysis the alternatives are as follows. Stage one is procedure to appraise investment alternatives of FMS and devide factors into strategic, analytic, economic viewpoint and draw upon decision making matrix through normalization Stage two is appraise to normalized alternatives using TOPSIS model among multiple attributes decision making models.

• 대한산업공학회지
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• 제25권1호
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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.

• 대한산업공학회지
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• 제22권1호
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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.

• 품질경영학회지
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• 제33권4호
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• pp.88-95
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• 2005

Multistage screening is a common practice when a component has a critical effect on the function of the assembly. A defect in a component might incur malfunction of an electronic device, resulting in a great amount of loss. Multistage screening, including duplicated screening inspections, may provide a good solution for this problem when inspection errors are present. In the company studied here, the manufacturing process of the multiple layer chip capacitor includes two-stage screening. In the first stage, screening inspection is performed repeatedly until no defects are found in the lot. In the second stage, sampling inspection is performed by a group of experts prior to shipment. In this article, we review the procedure used in the field and suggest a revised model of the multiple screening procedure and solution method for this situation. The usefulness of the proposed model is discussed through a practical example.

• 경영과학
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• 제11권2호
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• pp.1-27
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• 1994

A reliability data processing MPRDP (Multi-Purpose Reliability Data Processor) has been developed in FORTRAN language since Jan. 1992 at KAERI (Korean Atomic Energy Research Institute). The purpose of the research is to construct a reliability database(plant-specific as well as generic) by processing various kinds of reliability data in most objective and systematic fashion. To account for generic estimates in various compendia as well as generic plants' operating experience, we developed a 'three-stage' Bayesian procedure[1] by logically combining the 'two-stage' procedure[2] and the idea for processing generic estimates[3]. The first stage manipulates generic plant data to determine a set of estimates for generic parameters,e.g. the mean and the error factor, which accordingly defines a generic failure rate distribution. Then the second stage combines these estimates with the other ones proposed by various generic compendia (we call these generic book type data). This stage adopts another Bayesian procedure to determine the final generic failure rate distribution which is to be used as a priori distribution in the third stage. Then the third stage updates the generic distribution by plant-specific data resulting in a posterior failure rate distribution. Both running failure and demand failure data can be handled in this code. In accordance with the growing needs for a consistent and well-structured reliability database, we constructed a generic reliability database by the MPRDP code[4]. About 30 generic data sources were reviewed and available data were collected and screened from them. We processed reliability data for about 100 safety related components frequently modeled in PSA. The underlying distribution for the failure rate was assumed to be lognormal or gamma, according to the PSA convention. The dependencies among the generic sources were not considered at this time. This problem will be approached in further study.

• Journal of the Korean Data and Information Science Society
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• 제14권4호
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• pp.877-887
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• 2003

A two-stage procedure is proposed to estimate the population proportion of a sensitive group. The proposed procedure is obtained by combining the direct question method and a modified randomized response technique. It is verified that the proposed procedure is more efficient than existing methods under some mild conditions.