• 한국정밀공학회지
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• 제12권11호
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• pp.82-90
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• 1995

This paper pressents a condition-based maintenance (CBM) method through bibration analysis. The well known frequency analysis is employed for performing machine fault diagnosis. The statistical control chart is also applied for analyzing the trend of the bearing wear. Vibration sensors are attached to prototype machine and signals are continuously monitored. The sampled data are utilized to evaluate how well the fast fourier transform(FFT) and the statistical control chart techniques could be used to identify defects of machine and to analyze the machine degradation. Experimental results show that the propowed approach could classify every mal-function and could be utilized for real machine diagnosis system.

• Communications for Statistical Applications and Methods
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• 제30권4호
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• pp.355-368
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• 2023

This article introduces the R package ELCIC (https://cran.r-project.org/web/packages/ELCIC/index.html), which provides an empirical likelihood-based information criterion (ELCIC) for model selection that includes, but is not limited to, variable selection. The empirical likelihood is a semi-parametric approach to draw statistical inference that does not require distribution assumptions for data generation. Therefore, ELCIC is more robust and versatile in the context of model selection compared to the currently existing information criteria. This paper illustrates several applications of ELCIC, including its use in generalized linear models, generalized estimating equations (GEE) for longitudinal data, and weighted GEE (WGEE) for missing longitudinal data under the mechanisms of missing at random and dropout.

• 응용통계연구
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• 제20권2호
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• pp.257-266
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• 2007

모비율에 대한 신뢰구간의 구축에 있어 정규근사에 의한 Wald 신뢰구간이 표준으로 인식되어 왔으나, 최근 여러 학자들에 의해 Wald 신뢰구간은 근사성에서 심각한 문제가 있다는 것이 밝혀지고 있어 Agresti와 Coull(1998)에 의해 제안된 방법이 새로운 표준이 되어 가고 있다. Agresti-Coull 방법은 간편하면서도 근사성 문제를 획기적으로 개선하였으나 모비율에 대한 여러 가지 문제에서 보수적인 신뢰구간을 제시하고 있다. 본 연구에서는 베이지안 접근 방법에 의해 Agresti-Coull 방법의 보수성을 개선한 모비율 선형 함수의 신뢰구간을 제시한다.

• 지식경영연구
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• 제20권3호
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• pp.39-47
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• 2019

Response surface methodology (RSM) is a group of statistical modeling and optimization methods to improve the quality of design systematically in the quality engineering field. Its final goal is to identify the optimal setting of input variables optimizing a response. RSM is a kind of knowledge management tool since it studies a manufacturing or service process and extracts an important knowledge about it. In a real problem of RSM, it is a quite frequent situation that considers multiple responses simultaneously. To date, many approaches are proposed for solving (i.e., optimizing) a multi-response problem: process capability function approach, desirability function approach, loss function approach, and so on. The process capability function approach first estimates the mean and standard deviation models of each response. Then, it derives an individual process capability function for each response. The overall process capability function is obtained by aggregating the individual process capability function. The optimal setting is given by maximizing the overall process capability function. The existing process capability function methods usually use the arithmetic mean or geometric mean as an aggregation operator. However, these operators do not guarantee the Pareto optimality of their solution. Moreover, they may bring out an unacceptable result in terms of individual process capability function values. In this paper, we propose a maximin-based process capability function method which uses a maximin criterion as an aggregation operator. The proposed method is illustrated through a well-known multiresponse problem.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제42권3호
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• pp.144-150
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• 2016

Objectives: We compared the transbuccal and transoral approaches in the management of mandibular angle fractures. Materials and Methods: Sixty patients with mandibular angle fractures were randomly divided into two equal groups (A, transoral approach; group B, transbuccal approach) who received fracture reduction using a single 2.5 mm 4 holed miniplate with a bar using either of the two approaches. Intraoperatively, the surgical time and the ease of surgical assess for fixation were noted. Patients were followed at 1 week, 3 months, and 6 months postoperatively and evaluated clinically for post-surgical complications like scarring, infection, postoperative occlusal discrepancy, malunion, and non-union. Radiographically, the interpretation of fracture reduction was also performed by studying the fracture gap following reduction using orthopantomogram tracing. The data was tabulated and subjected to statistical analysis. A P -value less than 0.05 was considered significant. Results: No significant difference was seen between the two groups for variables like surgical time and ease of fixation. Radiographic interpretation of fracture reduction revealed statistical significance for group B from points B to D as compared to group A. No cases of malunion/non-union were noted. A single case of hypertrophic scar formation was noted in group B at 6 months postsurgery. Infection was noted in 2 patients in group B compared to 6 patients in group A. There was significantly more occlusal discrepancy in group A compared to group B at 1 week postoperatively, but no long standing discrepancy was noted in either group at the 6 months follow-up. Conclusion: The transbuccal approach was superior to the transoral approach with regard to radiographic reduction of the fracture gap, inconspicuous external scarring, and fewer postoperative complications. We preferred the transbuccal approach due to ease of use, minimal requirement for plate bending, and facilitation of plate placement in the neutral mid-point area of the mandible.

• 응용통계연구
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• 제10권1호
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• pp.47-60
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• 1997

본 논문에서는 그룹검사를 이용하여 질병률이 알려져 있지 않은 경우에 효율적인 혈액 검사 절차를 제시한다.

• 응용통계연구
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• 제8권2호
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• pp.163-177
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• 1995

이 글에서는, 중첩이나 누락으로 그 확률을 구하기 힘든 사건에 대해 경우의 수를 체계적으로 분류하여 구하는 방법의 일 예로서 7장 포커 약의 확률을 구한다. 7장 포커는 '1인 7장 스터드 카드'를 가정한다.

• 대한수학회보
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• 제37권3호
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• pp.451-459
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• 2000

In this paper, we observe the relation between the attainability of contingent claims and solutions of associated difference-differential equations. And we find the lower bound estimate of fair price using the minimax statistical approach.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.227.1-227
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• 2001

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 추계학술발표회요약집
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• pp.329-329
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• 2002