• 정보처리학회 논문지
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• 제13권5호
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• pp.227-235
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• 2024

원자력발전소에서 디지털 계측제어 시스템 비중이 높아지면서 원자력발전소에 대한 확률론적 안정성 평가 시 소프트웨어에 대한 신뢰도 평가가 중요해졌다. 원전 소프트웨어 신뢰도 추정을 위한 방법들이 몇 가지 제안 되었지만 해당 방법의 효과적 적용을 지원하는 도구 지원이 미비하였다. 본 연구에서는 소프트웨어 개발 품질 및 검증 품질과 같은 정성적 정보와 통계적 시험 결과와 같은 정량적 정보를 활용하여 원전 소프트웨어 신뢰도를 정량적으로 측정할 수 있는 자동화 도구를 설계하였고 구현하였다. 개발된 도구를 산업용 원자로 보호 시스템 사례에 적용한 결과, 개발된 도구가 원전 소프트웨어의 신뢰성 평가를 효과적으로 지원할 수 있음을 확인하였다.

• 한국강구조학회 논문집
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• 제19권2호
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• pp.223-231
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• 2007

풍속의 확률분포를 고려한 통영생산기지 LNG 하역설비인 Unloading arm의 신뢰성해석을 수행하였다. 기상대의 풍속 관측기록을 이용하여 풍속의 극치분포를 추정하였으며 구조물에 가해지는 풍하중은 풍속과 풍압계수를 적용한 분포하중으로 고려하였다. 하역설비는 판요소와 입체요소를 이용하여 모델링하였고 지면접촉부는 접촉요소를 이용하여 압축력에만 저항하도록 하였다. 신뢰성해석을 위해서 주요부위의 최대응력을 표현하는 응답면을 구하였으며 이 값이 허용응력 및 항복응력을 초과하는지의 여부를 신뢰함수로 정의하여 파괴확률을 구하였다. 또한, 재료강도의 저하가 파괴확률에 미치는 영향을 파악하기 위하여 민감도 분석을 수행하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권3호
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• pp.171-179
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• 2016

Purpose: The purpose of this study is to provide a comparison of reliability prediction models between MIL-HDBK-217F and Telcordia SR-332 and to analyze the reliability prediction results. Methods: The reliability of industrial tablet PC was predicted using MIL-HDBK-217F and Telcordia SR-332. To analyze the results, sensitivity analysis was conducted. Results: The reliability of MIL-HDBK-217F was predicted lower than the one of Telcordia SR-332. Considering the factors such as temperature, quality and environment, those provided reliability change of a particular part which highly contribute to the system failure. Conclusion: It is necessary to design the industrial tablet PC that consists of integrated circuits such as microprocessor and memory considering the operating temperature and quality factors.

• 드라이브 ㆍ 컨트롤
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• 제15권4호
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• pp.23-29
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• 2018

The objective of this paper is to evaluate the reliability of a volute pump and presents test results through performance and life tests. The performance and life test methods were presented by analyzing the failure modes of the volute pump. Zero failure test time was calculated to evaluate the reliability of the volute pump and then, the test was performed under accelerated conditions. The test was also carried out to check the failure modes of the field conditions. This study can be provided to improve the product reliability through failure analysis of the volute pump. And failure cause of typical failure case has been investigated and improvement design has been presented. The performance test results of before and after the accelerated life test were presented to confirm the improved reliability of the volute pump.

• 한국건설관리학회논문집
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• 제8권3호
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• pp.159-167
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• 2007

항만구조물의 계획 및 설계과정에서 VE/LCC분석을 통한 최적의 경제적인 의사결정이 더욱더 요구되고 있는 추세이나, 최근의 VE/LCC 설계자료를 분석해 보면 항만구조물의 열화성능에 대한 확률적 불확실성을 고려한 포괄적인 분석은 충분히 이루어지지 않은 실정이다. 본 연구에서는 퍼지 신뢰성 이론을 도입하여 항만구조물 중 방파제의 열화성능을 평가한 후 퍼지 신뢰성 해석에 따른 생애주기 비용으로 가치를 분석할 수 있는 VE/LCC 분석 모델을 개발하였고, 분석모델의 신뢰성과 활용성을 향상시키기 위한 측면에서 실제 대상 구조물에 적용한 결과, 기존의 확정론적 방법에서 고려되지 않는 데이터의 불확실량과 주관적 가치분석을 본 연구의 퍼지론적 방법에서 보다 합리적으로 반영할 수 있었고, 가치지향적 설계대안의 선정과 생애주기비용의 평가 및 유지관리조치를 위한 예산의 분배 등에 유리한 방법으로 평가되었다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권3호
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• pp.203-207
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• 2014

Electrodeless lamp is famous for its long life. But its reliability is dependent not only on electrodes but also on materials and structures. To evaluate end product's reliability, we studied high temperature durability by $60^{\circ}C$, $75^{\circ}C$ and $90^{\circ}C$ temperature tests, and predicted failure times by an exponential model through regression analysis. However, the test showed that temperature does not affect degradation of electrodeless lamps. Their luminous outputs degrade during the early time of the test (till 250 hours) and then converge to a saturation points. Also, '410nm ~ 530nm' spectrum degrades more than other spectra.

• 한국신뢰성학회지:신뢰성응용연구
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• 제4권2호
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• pp.121-131
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• 2004

HALT (Highly Accelerated Life Test) was performed to improve the reliability by removing the potential failure for newly developing PCB used for the vibration condition from 2OHz to 2OOHz. During HALT, it is found that the lead of Al electrolytic capacitor of SMD type is detached from PCB. As the result for the failure analysis and FEM (Finite Element Method), it is clarified that the root cause for this failure is the improper attachment of an Al electrolytic capacitor on PCB by the mistake of a PCB design. HALT was performed in previous condition to verify the failure analysis after molding an epoxy resin to overcome the PCB design mistake and it is not observed the same failure. Therefore, it is assumed that the same failure in field will be not occurred by the proper implementation.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권2호
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• pp.124-130
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• 2015

A stress-strength analysis is used to assess the reliability of a multi-pulse rocket motor system. Main stress is found to be thermal during explosion and the distribution is obtained by simulation. The strength distribution is derived from the results of actual specimen tests. The failure rate of barrier type pulse separation device is estimated.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권3호
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• pp.170-175
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• 2015

Reliability demonstration tests (RDT's) are widely employed in design verification and process validation stages of industry. New mixed attribute-variable RDT plans that compromise demerits of the corresponding zero and zero or one failure plans which are common in practice are developed for the exponential distribution. The proposed mixed plans are compared with the typical RDT plans in terms of probability of acceptance and expected test termination time. A numerical example is provided to illustrate the mixed plans and a procedure to extend these plans to the Weibull distribution with known shape parameter is also presented.

• 한국신뢰성학회지:신뢰성응용연구
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• 제12권4호
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• pp.275-285
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• 2012

This paper presents a changes of luminescence property for converted white LEDs with the commercially available silicate phosphor. If silicate phosphor's quantity increase step by step. luminescence property will be changing. we analyze luminescence property for these change and carry out the high temperature aging test for 7,000 hours, the high temperature and humidity aging test for 7,000 hours for reliability. LED degradation not only results in reduced light output but also in color changes. so we monitor correlated color temperature (CCT), chromaticity coordinates(x, y) and spectrum intensity. Those results suggest that humidity factor more bad effect in color changes than temperature factor and Lighting quality is related with quantity of phosphor.