• 산업경영시스템학회지
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• 제35권2호
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• pp.98-105
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• 2012

This paper describes the Bayesian approach for reliability demonstration test based on the samples from a finite population. The Bayesian approach involves the technical method about how to combine the prior distribution and the likelihood function to produce the posterior distribution. In this paper, the hypergeometric distribution is adopted as a likelihood function for a finite population. The conjugacy of the beta-binomial distribution and the hypergeometric distribution is shown and is used to make a decision about whether to accept or reject the finite population judging from a viewpoint of faulty goods. A numerical example is also given.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(I)
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• pp.27-43
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• 2003

Reliability Lifecycle from Concept to In-Service Operation and Maintenance. Reliability management must consider - SAFETY - SERVICE REQUIREMENTS. Reliability targets/objectives can be specified at feasibility stage. Reliability analysis to support design process. Reliability assessment to support reliability growth or contractual demonstration. Maintenance optimisation to improve reliability during lifetime of operation. Lessons learnt incorporated into next generation of trains.

• 품질경영학회지
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• 제25권3호
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• pp.96-107
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• 1997

The recent stream to reliability prediction is that it is totally inclusive in depth to consider even the operating and environmental condition at the level of finished goods as well as component itselves. In this study, firstly we present the reliability prediction methods by entire failure rate model which failure rate at the system level is added to the failure rate model at the component level. Secondly we build up the improved bases of reliability demonstration through a, pp.ication of Kaplan-Meier, Cumulative hazard, Johnson's methods as non-parametric and Maximum Likelihood Estimator under exponential & Weibull distribution as parametric. And also present the methods of curve fitting to piecewise failure rate under Weibull distribution, PRST (Probability Ratio Sequential Test), curve fitting to S-shaped reliability growth curve, computer programs of each methods. Lastly we show the practical for determination of optimal burn-in time as a method of reliability enhancement, and also verify the practical usefulness of the above study through the a, pp.ication of failure and test data during 1 year.

• 품질경영학회지
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• 제34권1호
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• pp.20-26
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• 2006

In the fields of mechanical reliability application, "zero" or "zero or one" failure tests are most commonly used for demonstrating reliability of a product since they reduce test duration and/or sample size compared to other test methods that guarantees the same reliability of a product with a given confidence level or consumer's risk. The test duration of the "zero or one" failure test is longer than that of "zero" failure test but it has advantage of smaller producer's risk. In this paper a two-stage test is developed that compromises the "zero" and "zero or one" failure tests. The properties of the proposed two-stage test are investigated and the three test methods are compared using a numerical example.

• 대한기계학회논문집A
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• 제38권10호
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• pp.1171-1177
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• 2014

전자파차폐용 문세트는 기계적 강도 및 내구성과 전자파 차폐라는 전기적 성능 요구를 동시에 충족시켜야 하므로 이에 알맞은 신뢰성입증시험법의 정립이 요구된다. 특히 전자파 차폐 성능에 직접적인 영향을 미치는 핑거스트립이라고 불리는 베링륨동 재질의 박형 스프링 하위 부품은 문짝과 직접적인 반복 건조마찰이 발생하므로 내구성에 만전을 기해야 하는 부위인데, 산업계에서는 주기적인 보전이 필요한 이 핑거스트립의 교체주기에 대한 보증도 또한 필요한 실정이다. 이러한 요구들에 대응하여 본 연구에서는 전자파차폐용문세트의 시험항목들을 정하고 전체 시스템 수명뿐만 아니라 교체품의 교체주기에 대한 보증을 단순한 방법으로 동시수행하는 입증시험을 설계하였다. 결론적으로 하위 교체부품을 가지는 직렬 시스템의 신뢰성입증시험에서는 교체품의 교체주기에 대한 보증도 항상 함께 포함시킬 것을 제안한다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권1호
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• pp.1-9
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• 2014

One important measure of performance for a repairable system is steady-state availability. In this paper, a method to estimate and establish confidence interval for the steady-state availability under Weibull lifetime and lognormal repair time distributions is proposed. Also, bias and mean squared error of a point estimator for an availability are investigated. In addition, a procedure to derive the sample size and critical value for availability demonstration test is presented and illustrated with a numerical example.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.683-688
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• 2007

The importance of reliability and safety, recently, shows a tendency to increases in railway system constructions and projects. At the point of view of safety, especially, the railway authority proposes an establishment of the safety case that is the documented demonstration that products comply with the specific safety requirements in railway industry. In case of reliability activities, there is no systematic documented demonstration in the railway industry. At this circumstance, this study presents the establishment of Reliability, Availability and Maintainability Case for railway system based on the MoD(Ministry of Defence) 00-42. This RAM Case will support that systems and products produced from suppliers or manufacturers meet the specific RAM requirements during the system life cycle(i.e, from design to operation & maintenance) through systematic process and evidences. Also, it is expected that railway system operations will be managed and supported from reliability activities in accordance with RAM Case.

• 한국철도학회논문집
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• 제9권6호
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• pp.732-738
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• 2006

This research provides a scheme for Highly Accelerated Stress Test that is necessary to demonstrate reliability prediction of Korean Rapid Transit Railway Train Control System sub-equipment, which is calculated by a relevant standard for failure rate prediction of electronic products. Although determining failure information generated in the process of trial running by statistic analysis is widely accepted as a measure of confirmation for reliability prediction, this research suggests the modeling for System Life Test determined by accelerating stress factors as a measure of confirmation for reliability prediction of sub-equipment unit that is generated ahead of a trial running in System Life Cycle. Consequently, the research demonstrates sub-equipment unit reliability test, which is based on the model derived from Accelerated Stress Test, according to accuracy level and the number of samples, and conducts an official experiment by making out a reliability test procedure sheet based on test time as well.

• 한국의류학회지
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• 제46권6호
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• pp.1161-1179
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• 2022

In this study, the effects of show host's verbal communication subfactors, such as paralanguage, friendliness, and professionalism, as well as nonverbal communication subfactors, such as demonstration attitude, appearance, and attractiveness, on purchase intention were examined by evaluating customer empathy and product reliability. Data was collected from 20s-50s females. SPSS 23.0 and AMOS 23.0 were used for data analysis. The results revealed that professionalism and friendliness had a positive impact on customer empathy; however, friendliness had a negative impact on product reliability. Moreover, nonverbal communication subfactors had a positive impact on empathy, and appearance had a positive impact on product reliability. In contrast, attractiveness had a negative impact on product reliability, whereas empathy and product reliability had a positive impact on purchase intention. Thus, ensuring appropriate verbal and nonverbal communication is essential for customer empathy and product reliability. Given that a show host's friendliness, professional verbal communication, demonstration attitude, appearance, and attractiveness have a positive impact on customer empathy, these factors should be considered critical qualities of show hosts.

• Nuclear Engineering and Technology
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• 제49권2호
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• pp.360-372
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• 2017

Many advanced reactor designs rely on passive systems to fulfill safety functions during accident sequences. These systems depend heavily on boundary conditions to induce a motive force, meaning the system can fail to operate as intended because of deviations in boundary conditions, rather than as the result of physical failures. Furthermore, passive systems may operate in intermediate or degraded modes. These factors make passive system operation difficult to characterize within a traditional probabilistic framework that only recognizes discrete operating modes and does not allow for the explicit consideration of time-dependent boundary conditions. Argonne National Laboratory has been examining various methodologies for assessing passive system reliability within a probabilistic risk assessment for a station blackout event at an advanced small modular reactor. This paper provides an overview of a passive system reliability demonstration analysis for an external event. Considering an earthquake with the possibility of site flooding, the analysis focuses on the behavior of the passive Reactor Cavity Cooling System following potential physical damage and system flooding. The assessment approach seeks to combine mechanistic and simulation-based methods to leverage the benefits of the simulation-based approach without the need to substantially deviate from conventional probabilistic risk assessment techniques. Although this study is presented as only an example analysis, the results appear to demonstrate a high level of reliability of the Reactor Cavity Cooling System (and the reactor system in general) for the postulated transient event.