• International Journal of Ocean System Engineering
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• 제2권4호
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• pp.250-258
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• 2012

The distribution of wave heights is assumed to be a Rayleigh distribution, based on the assumption of a narrow band and Gaussian distribution of wave elevation. The present study was started with doubts about the narrow band assumption. We selected the wave spectra widely used to simulate irregular random waves. The wave spectra used in this study included the Pierson-Moskowitz spectrum, Bretschneider-Mitsuyasu spectrum, and JONSWAP spectrum. The directionality of the waves was considered. The cosine 2-l type directional spreading function and mixed form of the half-cosine 2-s type with Mitsuyasu type directional spreading are considered here to investigate the effects of a directional spreading function on random waves. The simulated wave height distribution is compared with a Rayleigh distribution.

• 정보처리학회논문지A
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• 제9A권2호
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• pp.267-270
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• 2002

비중심 $\chi^2$분포의 누적분포 함수의 계산은 $\chi^2$검정에서 검정력 계산에 요구된다. 본 논문서는 중심 $\chi^2$분포 함수를 통하여 비중심 $\chi^2$분포 함수의 계산을 구하는 알고리즘을 제시하고 있으며 기존의 접근 방법에 의한 계산 결과와 비교하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제31권8호
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• pp.954-960
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• 2007

The purpose of this paper is to obtain design method of air-distribution system. Air-distribution system is composed of blower, duct, diffusers and measuring equipment. The air-flow rate from each diffuser is not equal. The air-flow rate is calculated with the combined equations which are Bernoulli's equation, continuity equation and minor loss equations. Inlet condition and outlet condition are adapted in each duct system. Then square difference between function of maximum air-flow rate and minimum air-flow rate is used as an object function. Area of diffuser and velocity are established as constraints. To minimize the object function, the optimization method is used. After optimization the design variables are selected under satisfaction of constraints. The air-distribution system is calculated again with the result of optimized design variable. It is shown that the air-distribution system has the equal air-flow rate from diffusers.

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.166-175
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• 1995

When a neutral particle beam(NPB) aimed at the object and receive a small number of neutron signals at the detector without any errors, it obeys Poisson law. Under the two assumptions that neutral particle scattering distribution and aiming errors have a circular Gaussian distributions that neutral particle scattering distribution and aiming errors have a circular Gaussian distribution respectively, an exact probability distribution of neutral particles vecomes a Poisson-power function distribution. We study and prove some properties, such as limiting distribution, unimodality, stochastical ordering, computational recursion fornula, of this distribution. We also prove monotone likelihood ratio(MLR) property of this distribution. Its MLR property can be used to find a criteria for the hypothesis testing problem.

• 한국산학기술학회논문지
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• 제7권3호
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• pp.393-397
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• 2006

신제품에 대한 개발 주기가 짧아지고 있는 현시점에서 제품의 수명을 예측하고 평가하기 위한 방법으로 가속 수명시험과 시험을 통해 관측된 고장 데이터의 분석에 대한 관심이 증대되고 있다. 이에 따라 가속 수명시험을 위한 시험 조건과 고장 데이터의 정확한 분석을 위한 고장 데이터의 최적 분포 결정 방법에 대한 관심 또한 증대되고 있다. 따라서 본 논문에서는 고장 데이터를 기반으로 신뢰성 예측을 할 때 사용하는 분포 함수 결정을 위한 방법으로 관측된 고장 데이터만의 분포를 고려하는 Anderson-Darling 방법과 관측된 고장 데이터의 수명-스트레스 관계식을 적용하여 고장 데이터의 분포를 결정하는 Likelihood Function 방법을 비교한다. 두 가지 방식을 비교한 결과 각 방식에 의해 선택되는 최적분포가 다르며, 따라서 각 방식에 의해 선택된 최적 분포에 의해서 예측되는 수명도 다름을 알 수 있다.

• 대한수학회논문집
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• 제19권1호
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• pp.169-177
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• 2004

For a stationary field $\{X_{\b{j}},\b{j}{\;}\in{\;}{\mathbb{Z}}^d_{+}\}$ of associated random variables with distribution function $F(x)\;=\;P(X_{\b{1}}\;{\leq}\;x)$ we study strong consistency and asymptotic normality of the empirical distribution function, which is proposed as an estimator for F(x). We also consider strong consistency and asymptotic normality of the empirical survival function by applying these results.

• Communications for Statistical Applications and Methods
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• 제8권1호
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• pp.229-235
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• 2001

Let {X$\_$n/, n$\geq$1] be a stationary sequence of negatively associated random variables with distribution function F(x)=P(X$_1$$\leq$x). The empirical distribution function F$\_$n/(x) based on X$_1$, X$_2$,....., X$\_$n/ is proposed as an estimator for F$\_$n/(x). Strong consistency and asymptotic normality of F$\_$n/(x) are studied. We also apply these ideas to estimation of the survival function.

• Journal of the Korean Data and Information Science Society
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• 제25권3호
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• pp.623-632
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• 2014

We shall consider the estimation for the parameter and the right tail probability in a general exponential distribution. We also shall consider the estimation of the reliability P(X < Y ) and the skewness trends of the density function of the ratio X=(X+Y) for two independent general exponential variables each having different shape parameters and known scale parameter. We then shall consider the estimation of the failure rate average and the hazard function for a general exponential variable having the density function with the unknown shape and known scale parameters, and for a bivariate density induced by the general exponential density.

• 한국안전학회지
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• 제31권4호
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• pp.48-54
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• 2016

The prediction of various emissions from coal combustion is an important subject of researchers and engineers because of environmental consideration. Therefore, the development of the models for predicting pollutants very fast has received much attention from international research community, especially in the field of safety assessment. In this work, response surface method was introduced as a design of experiment, and the database for RSM was set with the numerical simulation of a drop tube furnace (DTF) to predict the spatial distribution of pollutant concentrations as well as final ones. The distribution of carbon dioxide in DTF was assumed to have Boltzman function, and the resulted function with parameters of a high $R^2$ value facilitates predicting an accurate distribution of $CO_2$. However, CO distribution had a difference near peak concentration when Gaussian function was introduced to simulate the CO distribution. It might be mainly due to the anti-symmetry of the CO concentration in DTF, and hence Extreme function was used to permit the asymmetry. The application of Extreme function enhanced the regression accuracy of parameters and the prediction was in a fairly good agreement with the new experiments. These results promise the wide use of statistical models for the quantitative safety assessment.

• 한국전자파학회논문지
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• 제23권7호
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• pp.822-830
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• 2012

클러터는 레이더로 수신되는 불필요한 신호로 표적 탐지에 영향을 준다. 레이더 클러터는 진폭 분포, 주파수 스펙트럼 등과 같은 특성으로 정의되며, 이러한 특성을 충분히 고려하여 클러터 모델링 및 신호 생성이 되어야 한다. 본 논문에서는 다양한 클러터의 모델링에 광범위하게 사용되는 Weibull 분포 함수를 균일 분포 함수를 이용하여 단순화한 근사적 모델링 기법에 대하여 제안한다. 제안된 Weibull 분포 함수 근사 해에 의해 발생된 데이터가 원 Weibull 확률 밀도 함수를 만족하며, 생성 시간은 약 20 % 감소함을 실험 결과를 통하여 입증한다.