• 한국군사과학기술학회지
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• 제14권5호
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• pp.850-858
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• 2011

The risk analysis plays an important role in weapon system acquisition project due to uncertainties in the acquisition process. But in domestic, studies on risk analysis are insufficient and risk cost is not included in acquisition budget in policy. Therefore, in this study, we suggest a method that measures risk or success probability of project using the stochastic model. In particular, in order to calculate the success probability, we apply the joint probability distribution model of cost and schedule that are critical factors influencing the project risk. And also we verify the applicability of this model in Korean defence industry environment through case studies.

• 대한기계학회논문집A
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• 제41권11호
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• pp.1085-1089
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• 2017

주령구는 안압지에서 출토된 14면체 주사위인데, 6개의 정사각면과 8개의 육각면으로 구성되어 있으며, 14개의 면에는 각각 다른 문구가 새겨져 있다. 본 연구에서는 이러한 14면체 주사위를 정밀하게 가공한 뒤, 실험을 통해 육각면이 나올 확률을 조사하였다. 다음으로 다물체동역학 모델링을 통하여 육각면이 나올 확률을 알아본 뒤, 마찰계수에 따라 확률이 달라지는 분석하였다.

• 상하수도학회지
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• 제23권3호
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• pp.295-303
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• 2009

In the present study, a reliability analysis calculating the probability of system failure has been performed using cut set and results of numerical analysis for unsteady flow in pipe. Especially, the probability of system failure has been evaluated regarding the effect of valve closure which is a really important activity in operation of piping system. In spite of small amount of demand, it was found that fast valve closure can generate high probability of system failure. Furthermore, it was confirmed that surge tank can reduce the unsteady effects and probability of system failure in water distribution system. From the results, it was found that the unsteady flow has a significant effect on the probability of system failure Furthermore, it was able to find which pipe or cut set has high probability of system failure. So it could be used to determine which pipe or cut set has a priority of repair and replacement. Therefore, reliability analysis regarding unsteady flow has to be performed for the planning, designing, maintenance, and operation of piping system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.44-51
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• 2001

To account for uncertainties involved in an economic analysis of project, sensitivity analysis are usually being done in Korea. Though useful for policy analysis, but it larks explicit consideration of probability of occurring certain events considered in the sensitivity analysis. Risk analysis otherwise can explicitly account for the probability of certain event which has dire impact on project viability, such as cost, discount rate, and size of benefit. This paper reports experience of applying risk analysis method for economic evaluation of railroad investment. Probability distribution of event has paramount impact on the risk analysis results, while not many prior researches dealt with these issues. Probability distribution of rolling stock cost and operating cost, in addition to those cost variables, are developed considering railway demand in this study. Case study results are reported. Issues in applying risk analysis are reported in addition to further research direction.

• 한국수자원학회논문집
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• 제43권2호
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• pp.187-199
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• 2010

본 연구는 최근에 개발된 비정상성 강우빈도해석법을 적용하여 추정한 확률강우량에 대한 적용성 및 신뢰성을 평가하였다. 이를 위하여 기상청 관할 강우관측소 중 자료의 증가 경향성이 유의한 4개 지점에 대하여 3가지 형태의 확률강우량을 산정하였다. 첫 번째 확률강우량은 1973-1997년의 관측자료를 가지고 일반적인 강우빈도해석을 적용하여 추정한 확률강우량(SPR1997)이고, 두 번째 확률강우량은 1973-2006년의 관측자료를 가지고 일반적인 강우빈도 해석을 적용하여 추정한 확률강우량(SPR2006), 그리고 세 번째 확률강우량은 1973-1997년의 강우량 자료를 가지고 1997년을 현재시점이라 가정하여 2006년의 확률강우량을 비정상성 강우빈도해석법을 적용하여 추정한 확률강우량(NSPR2006)이다. 2006년을 목표연도라 가정하고, 확률강우량을 비교분석한 결과, 비정상성 강우빈도해석법에 의한 확률강우량(NSPR2006)이 정상성 확률강우량(SPR1997)에 비해 목표연도의 확률강우량에 대하여 적절한 값을 추정하는 것으로 나타났다. 본 연구는 또한 Bootstrap 기법을 이용한 신뢰구간을 비교하여 비정상성 확률강우량 추정에 적용되는 매개변수 추정법에 대한 평가를 수행하였다. 최우도법에 의한 신뢰구간 길이가 확률가중모멘트법에 의한 신뢰구간 길이보다 좁게 나타났으며, 이는 최우도법이 비정상성 강우빈도해석법에 적용되어 신뢰성 높은 확률강우량을 추정하는 것으로 판단된다.

• 한국환경과학회지
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• 제2권3호
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• pp.235-243
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• 1993

Extreme environments and freak wave characteristics in the coastal waters of Korean Peninsula are analyzed using the observed wave data. Freak wave has been intensely emphasized as an important environmental force parameter in several recent research works. However, the mechanism and occurrence probability of freak wave are not clarified. The aims of this study we: to summarize the distribution of extreme environment for wind waves, and to find occurrence probability of freak wave in the coastal waters of Korean Peninsula. These extreme sea conditions are discussed by applying extreme value analysis method, and the statistic characteristics are summarized which can be used to the design and analysis of coastal structures. The mechanism and the occurrence probability of freak wave are also discussed in detail using wave parameters in considered with wave deformation in the coastal waters. Key Words : extreme wave, freak wave, extreme analysis, design wave, probability density.

• 한국농공학회논문집
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• 제54권4호
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• pp.39-46
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• 2012

The objectives of this study is intended to analyze stresses using the boundary element method and probability analysis for agricultural structure. Loads and material properties are an important factor when analyzing the structure. Until now, designing structure, loads and material properties are applied deterministic value. However, load and material properties involve uncertainties due to those change probabilistic and deterministic methods could not consider uncertainties. To solve these problems, the reliability analysis based on probability properties scheme was developed. Reliability analysis is easy to approach to analysis frame structure, however it has limitation when solving plane stress strain problems a kind of agricultural structures. The BEM (Boundary Element Method) is able to analysis plane strain problems by boundary conditions. Thus, this study applied boundary element method to analysis plane strain problem, load and material properties as a probabilistic value to calculate the analytical model using Monte Carlo simulations were developed.

• 대한기계학회논문집A
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• 제28권6호
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• pp.685-692
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• 2004

A stochastic approach has been presented for superplastic deformation of Ti-6Al-4V alloy, and probability functions are used to model the heterogeneous phase distributions. The experimentally observed spatial correlation functions are developed, and microstructural evolutions together with superplastic deformation behavior have been investigated by means of the two-point and three-point probability functions. The results have shown that the probability varies approximately linearly with separation distance, and deformation enhanced probability changes during the process. The stress-strain behavior with the evolutions of probability function can be correctly predicted by the model. The finite element implementation using Monte Carlo simulation associated with reconstructed microstructures shows that better agreement with experimental data of failure strain on the test specimen.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.865-869
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• 2008

Juryeonggu is a Cuboctahedral die that had used in ancient Korea. This Cuboctahedral is consisted of different two penal servitudes of 14 facepieces, but the probability distribution can appear equally so it can be usable as a die. In this paper, achieved research study about probability of a Cuboctahedral die that have quadrilateral and triangle preferentially to search Juryeonggu's probability calculation method. First, confirmed probability distribution through Multibody-dynamics analysis and verified probability distribution through several experiments. Finally, with this simulation data, achieved theoretical analysis about Cuboctahedral die occurrence probability by using the residual momentum energy.

• 한국수학교육학회지시리즈A:수학교육
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• 제58권4호
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• pp.531-543
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• 2019

본 연구는 2009개정 교육과정과 2015개정 교육과정을 반영한 교과서에서 연속확률분포를 정의하고 도입하는 방법에 대해 비교 분석하였다. 2015개정 교육과정을 반영한 확률과 통계 교과서는 연속확률변수를 가부번집합인 확률변수로 정의하기보다는 특정 범위의 모든 실숫값을 가지는 확률변수로 정의하였다. 또한 연속확률분포를 도입함에 있어 균등분포를 이용한 방법과 상대도수밀도를 이용한 방법을 사용하였다.