• 한국의류학회지
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• 제30권9_10호
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• pp.1366-1377
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• 2006

The purposes of this study was to find out 1) the difference in the importance degree of store attribute according to interaction between fashion product types and task situations, 2) the difference in the importance degree of store attribute according to the patronized store types on the basis of fashion product types. The subjects were female adults who lived in Seoul. The sampling method was quota sampling. The data was obtained from 391 questionnaires. The data were analyzed using frequency, one-way ANOVA, Duncan test, and two-way ANOVA by means of SPSS. The results were as follows; 1. According to fashion product types and task situations, there were significant differences in factors of product features, services, physical environments of the store, and price. 2. According to interaction between fashion product types and task situations, there were significant differences in factors of product features, services, physical environments of the store, and price. 3. There were significant differences in factors of product features, services, physical environments of the store, and location of store according to patronized store types, when a consumer purchased a suit, casual wear and inner wear.

• 자원환경지질
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• 제52권2호
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• pp.199-212
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• 2019

머신러닝 기법을 활용한 분석에서 훈련 데이터의 샘플링 전략은 예측 정확도 뿐 만 아니라 일반화 능력에도 많은 영향을 미친다. 특히, 산사태 취약성 분석의 경우, 산사태 발생부에 대한 정보에 비해 산사태 미발생부에 대한 정보가 과도하게 많은 데이터 불균형 현상이 발생하며, 이에 따라 분석 모델의 훈련 데이터 설계 시 데이터 샘플링 과정이 필수적이다. 그러나 기존의 연구들은 대부분 산사태 미발생부 선택 시 발생부 데이터와 1:1의 비율을 갖도록 무작위로 선택하는 방법을 적용하였을 뿐, 특정한 선택 기준에 따라 분석을 수행하지 않았다. 따라서 본 연구에서는 훈련 데이터의 샘플링 전략이 모델의 예측 성능에 미치는 결과를 확인하기 위하여 산사태 발생부와 미발생부의 샘플링 전략기준에 따라 서로 다른 6개의 시나리오를 만들어 Random Forest 모델의 훈련에 사용하였다. 또한 Random Forest의 결과 중 하나인 변수 중요도를 각 산사태 유발인자들에 가중치로 곱하여 줌으로써 산사태 취약지수 값을 산정하였으며, 취약지수 값을 이용해 산사태 취약성도를 제작하고 각 결과 지도의 정확도를 비교 분석하였다. 분석 결과, 훈련데이터의 샘플링 방법에 상관없이 두 지역의 산사태 취약성 분석 결과는 모두 70~80%의 정확도를 보였다. 이를 통해 Random Forest 기법의 산사태 취약성 분석기법으로서의 적용 가능성을 확인하였으며, Random Forest 모델이 제공하는 입력변수의 중요도를 산사태 유발인자 가중치로 활용할 수 있음을 확인하였다. 또한 훈련 시나리오 간의 정확도를 비교한 결과, 특정한 기준에 의해 훈련 데이터를 설계하는 것이 기존의 랜덤 선택 방법보다 높은 예측 정확도를 기대할 수 있음을 확인하였다.

• 대한산업공학회지
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• 제11권2호
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• pp.11-18
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• 1985

Three types of warranty policies are considered. They are (1) free warranty policy for repairable products, (2) free warranty policy for nonrepairable products, and (3) rebate warranty policy. Under each warranty policy, a single sampling attribute plan with non-destructive testing is considered. A sampling plan is characterized by the sample size and the acceptance number. For each case, characteristics of an optimum sampling plan are discussed and determined, which minimize the warranty cost and the corresponding quality control cost within the assigned producer's risk and consumer's risk.

• 산업경영시스템학회지
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• 제8권11호
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• pp.85-95
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• 1985

This thesis is a study on the work sampling method which is one of the important parts in the fields of work measurement today. The primary objective of this study is to examine various methods of selecting observation times in work sampling studies, including simple random systematic, and stratified sampling and a new method called restricted random sampling. The attribute of these sampling methods are explained, particulary statistical efficiency, and the important advantages of stratification are analysed. A case study of work sampling was made in a manufacturing plant to show its practical application and the effectiveness of the stratified random sampling technique.

• 대한안전경영과학회지
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• 제9권2호
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• pp.215-233
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• 2007

Even though the ad hoc Shewhart methods remain controversial due to various mathematical flaws, there is little disagreement among researchers and practitioners when a set of process data has a skewness distribution. In the context and language of process control, the error related to the process data shows that time to signal increases when a control parameter shifts to a skewness direction. In real-world industrial settings, however, quality practitioners often need to consider a skewness distribution. To address this situation, we developed an enhanced design method to utilize advantages of the traditional attribute control chart and to overcome its associated shortcomings. The proposed design method minimizes bias, i.e., an average time to signal for the shift of process from the target value (ATS) curve, as well as it applies a variable sampling interval (VSI) method to an attribute control chart for detecting a process shift efficiently. The results of the factorial experiment obtained by various parameter circumstances show that the VSI c control chart using nearly unbiased ATS design provides the smallest decreasing rate in ATS among other charts for all experimental cases.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1993년도 춘계공동학술대회 발표논문 및 초록집; 계명대학교, 대구; 30 Apr.-1 May 1993
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• pp.438-438
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• 1993

• Industrial Engineering and Management Systems
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• 제13권1호
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• pp.101-106
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• 2014

New control charts under repetitive sampling are proposed, which can be used for variables and attributes quality characteristics. The proposed control charts have inner and outer control limits so that repetitive sampling may be needed if the plotted statistic falls between the two limits. Particularly, the new np and variable X-bar control charts under repetitive sampling are considered in detail. The in-control and out-of-control average run lengths are analyzed according to various process shifts. The performance of the proposed control charts is compared with the existing np and the X-bar control charts in terms of the average run lengths.

• 산업경영시스템학회지
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• 제4권5호
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• pp.11-14
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• 1981

This study intends to decide the economic sample size based on the cost of sampling Inspection for destructive testing. The marginal percent defective is used as the lot tolerance percent defective (LTPD), and the Newton's iterative method is adopted to calculate the optimum sample size(n), given by the consumer's risk($\beta$ - risk) and the acceptance number(c).

• 품질경영학회지
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• 제13권2호
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• pp.48-55
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• 1985

This paper intends to decide the optimum OC curves and to find the minimized ${\alpha}$, ${\beta}$-risk based upon the Linear Cost Model (L.C.M.) for the destructive or nondestructive acceptance sampling inspection plan. For the solution from the L.C.M., we assume the uniform distribution as a Prior-distribution and use numerical analysis by computer.

• 산업기술연구
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• 제3권
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• pp.27-32
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• 1983

This paper develops and provides formulas for calculating the Average Outgoing Quality and the Average Total Inspection for nine different sample/rest-of-lot disposition policies in which rectifying multiple sampling inspection by attribute can be carried out. The formulas are considered for perfect inspection as well as error-prone inspection.