• 대한안전경영과학회지
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• 제7권4호
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• pp.101-110
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• 2005

The likelihood of failure for the thinning of high temperature sulfide and naphthenic acid corrosion, which affect to a risk of facilities, was analyzed through the risk based inspection using API-581 BRD. We found that the corrosion rate was increased with increasing temperature and total acid number(TAN). And maximum value of the technical module subfactor(TMSF) was not varied with operating condition, but the TMSF was sensitively changed at the range of low temperature, low flow rate, and high TAN. Also, the TMSF was increased as an used year and inspection effectiveness increased, but it was increased as thickness, inspection number, and over design decreased.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.315-322
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• 1999

The probabilistic keyblock concept which was based upon block theory was applied to the example site by using the observed block moulds data. The more was the block failure likelihood (P(B)) which was defined by the product of the joint combination probability, the shape parameter and the instability parameter, the more were the frequencies of failures observed. If we can acquire these data during a tunnel construction stage, they will be used as a very useful data to construct another tunnel in the neighborhood. Furthermore, a sedimentary rock may have larger P(B) values than a crystalline rock, and for the given P(B) value, the percent block moulds are larger in the former than latter.

• 품질경영학회지
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• 제13권1호
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• pp.31-40
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• 1985

In this paper, statistical estimation of the parameters of the bivariate exponential distribution are studied. Bayes estimators of the parameters are obtained and compared with the maximum likelihood estimators which are introduced by Freund. We know that the method of moments estimators coincide with the maximum likelihood estimators and Bayes estimators are more efficient than the maximum likelihood estimators in moderate samples. The asymptotic distributions of the maximum likelihood estimators and the estimator of mean time to system failure are obtained.

• Journal of the Korean Data and Information Science Society
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• 제16권2호
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• pp.383-389
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• 2005

In this paper, we propose the pure premium rate of reliability insurance policy for radiators under the assumption of Weibull physics of failure. We also describe the performance factors which have an effect on failure characteristics of radiators. The maximum likelihood estimates of scale and shape parameters for assumed distribution are obtained by using accelerated life test data of sample sizes 5 using MINITAB.

• Journal of the Korean Data and Information Science Society
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• 제15권1호
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• pp.49-57
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• 2004

In this paper, we calculate the premium rate of reliability insurance policy for wiper motors under the assumption of Weibull physics of failure. We also describe the performance factors which have an effect on failure characteristics of wiper motors. The maximum likelihood estimates of shape parameter and scale parameter are obtained by using interval censored real data of sample sizes 6 using MINITAB.

• Journal of the Korean Data and Information Science Society
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• 제16권2호
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• pp.401-410
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• 2005

In this paper, we calculate the premium rate of reliability insurance policy for brake pads for automobiles using real failure data obtained from use-condition. We try process capability analysis for the manufacturing process of brake-system. We describe the performance factors which have an effect on failure characteristics of brake pads. We also obtain the maximum likelihood estimates of shape and scale parameters of the fitted Weibull distribution for brake pads.

• International Journal of Reliability and Applications
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• 제7권1호
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• pp.41-53
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• 2006

The exact cause of the system's failure is often unknown in the masked system lifetime data. In such type of data, there are two observable quantities, namely (i) the systems time to failure and (ii) the set of systems components that contains the component, which might cause the system to fail. Our objective in this paper is to use the maximum likelihood procedure in the presence of masked data to make inference for the reliability of the system's components. We assume a multi-component series system where each component has a constant failure rate. Different cases that permit for closed form solutions of point estimates are considered. The results obtained in this paper generalize other published results.

• International Journal of Reliability and Applications
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• 제12권1호
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• pp.1-14
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• 2011

This paper discusses the stochastic analysis and the statistical inference of a quadratic failure rate semi-Markov reliability model. Maximum likelihood procedure will be used to obtain the estimators of the parameters included in this reliability model. Based on the assumption that the lifetime and repair time of the system units are random variables with quadratic failure rate, the reliability function of this system is obtained. Also, the distribution of the first passage time of this system is derived. Many important special cases are discussed.

• Journal of the Korean Data and Information Science Society
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• 제20권3호
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• pp.467-474
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• 2009

시스템의 한 부품이 고장 나면 고장 난 부품이 분담하던 부하가 고장 나지 않은 다른 부품에 전가되어 다른 부품의 고장률에 영향을 주는 부하분배시스템에 대한 연구가 신뢰성 공학과 생물의학 분야에서 다양하게 이루어져왔다. 본 연구에서는 최소수명을 보증하는 부하분배체계의 체계단위수명 시험에서 부품의 수명관측이 불가능하며 체계의 수명관측이 가능한 경우에, 중도절단된 체계 고장데이터를 이용하여 부하분배체계의 평균수명과 체계 신뢰도의 최우추정치와 추정오차를 줄일 수 있는 수정된 최우추정치를 구하고 컴퓨터 모의실험을 통하여 그 성능을 비교한다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제1권1호
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• pp.47-54
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• 2001

This paper considers the parameter estimation problem of the failure intensity function and maintenance effect in a repairable system. We propose estimation procedures for repairable systems on which preventive maintenance is performed. The failure process is modeled by a proportional age reduction model [Brown, Mahoney and Sivazlian(1983)] which is useful to model the imperfect effect of preventive maintenance. When failure and maintenance (preventive) times are given, the maximum likelihood method is used to estimate the maintenance effect and the parameters of intensity function, simultaneously We obtain the maximum likelihood estimators using a genetic algorithm. A numerical example is also presented.