• 한국지반공학회논문집
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• 제26권7호
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• pp.161-170
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• 2010

기초구조물의 저항계수 산정 및 하중저항계수설계법의 개발을 위해서는 충분한 양의 데이터베이스 구축을 바탕으로 정확한 신뢰성 분석이 수행되어야 한다. 기존 국내외 말뚝기초의 신뢰성 분석 연구에서는 말뚝의 측정지지력 확인이 가능한 재하시험 자료만을 이용하여 저항편향계수의 분포특성을 산정하였다. 따라서, 파괴에 이르지 않은 말뚝재하시험 자료는 신뢰성 분석에서 제외되었다. 본 연구에서는 베이지안 이론을 이용하여 타입강관말뚝 저항편향계수의 사전 분포특성에 측정지지력을 확인할 수 없는 재하시험 결과를 추가하여 현장 특성을 반영한 저항편향계수의 사후분포특성을 산정하였다. 그리고 저항편향계수의 사후분포특성을 이용하여 말뚝의 신뢰성 평가를 수행하고 신뢰도수준을 갱신하였다. 국내 전역에서 수행된 양질의 정재하시험 자료를 수집, 분석하여 57개의 자료에 대한 측정지지력을 확인하였고, 이들 자료에 대해서 구조물기초설계기준에서 제안하고 있는 Meyerhof 공식을 이용하여 설계지지력을 산정하였다. 이를 통해 저항편향계수의 사전분포 특성을 정량화 하였으며, 베이지안 기법을 적용하여 다양한 현장재하시험 결과에 따라 저항편향계수의 사후분포를 산정하였다. 갱신된 저항편향계수 통계특성을 적용하여 일차신뢰도법을 이용하여 강도 높은 신뢰성 해석을 수행하고 시험결과에 따른 신뢰도 수준을 평가하였다. 본 연구에서 제시된 방법을 통해 양질의 측정지지력 데이터가 부족한 경우 베이지안 기법을 이용하여 신뢰성 분석이 가능함을 확인하였다.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2004년도 정기학술대회
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• pp.303-311
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• 2004

This paper presents the reliability estimation of door hinge for home appliances, which consists of bushing and shaft. The predominant failure mechanism of bushing made of polyoxymethylene(POM) is brittle fracture due to decrease of strength caused by voids existing, and that of shaft made of acrylonitrile-butadiene-styrene(ABS) is creep due to plastic deformation caused by excessive temperature and lowering of glass transition temperature by absorbed moisture. Since the brittle fracture of bushing is overstress failure mechanism, the load-strength interference model is used to estimate the failure rate of it along with failure analysis. By the way, the creep of shaft is wearout failure mechanism, and an accelerated life test is then planned and implemented to estimate its lifetime. Through the technical review about failure mechanism, temperature and humidity are selected as accelerating variables. Assuming Weibull lifetime distribution and Eyring model, the life-stress relationship and acceleration factor, B$_{10}$ life and its lower bound with 90% confidence at worst case use condition are estimated by analyzing the accelerated life test data.a.

• 산업경영시스템학회지
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• 제33권4호
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• pp.209-217
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• 2010

Reliability tools such as QFD and FMEA identify voice of customer related to product design, its use, how failures may occur, the severity of such failures, and the probability of the failure occurring. With these identified items, a development team can focus on the design process and the major issues facing the product in its potential use environment for the customer. The purpose of this research is to develop a reliability estimation process of agricultural machinery components using QFD, FMEA, and field failure data. Based on QFD method, customer requirements, engineering design elements and part characteristics were deployed. Using the field failure data, failures are investigated, and Weibull B10 life are estimated. This estimation process is useful for preparing the design input and planning the durability target.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2011년도 춘계학술발표대회 논문집
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• pp.265-270
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• 2011

This paper describes a reliability/durability test of the remanufactured steering gear units. There used to be government restrictions to remanufacture certain types of automotive components regarding safety of passengers. Nevertheless, scientific approach to sustainability and remanufacturing process provided solid evidence of highly beneficial sides of reusing the products. Failure mode analysis of the steering gear unit is performed and main failure is found out. The unit is remanufactured by fixing the failure and its quality is assessed through designing a new sequence of loading events. Oil leakage is witnessed as a possible failure and its volume is measured. Conclusions based on laboratory condition durability test are given at the end.

• 한국가스학회지
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• 제21권4호
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• pp.16-20
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• 2017

현재의 유지보수 시스템은 고정 설비 및 회전기계의 유지 및 보수에 대한 명확한 기준이 제시되지 않고 있으며, 고장이 발생되더라도 근본적인 원인분석 없이 교체 및 수리가 이루어져 더 큰 사고를 초래할 수 있는 환경이다. 따라서 본 연구에서는 예방보전을 통해 사전에 점검하고 유지 보수할 수 있도록 신뢰성 중심의 유지보수 시스템의 절차를 개발하였고, 향후 유지보수에서 설비의 고장형태에 따라 문제 발생 설비를 집중 관리함으로써 중대산업사고의 발생을 사전에 예방하고 관리할 수 있는 절차를 제시하고자 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.130-132
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• 2006

For the reliability assessment of solenoid actuator, firstly, we analyzed the cause of major failures and the effect of each failure modes through FMEA and FTA, and decided the main test items through 2-stage QFD. And then, as a measure of life of solenoid actuator, TypeII censored five data were collected from and operation test which was performed as the life test of solenoid actuator. In this paper, we present the reliability parameters of solenoid actuator like shape parameter, scale parameter, etc., which they are produced by MINITAB analysis and marking of Weibull probability paper using the measure of life, and also present the 6 kinds of detailed failure mode analysis.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.471-474
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• 2005

Reliability-based durability model was developed to consider the uncertainty of analysis variables in durability model for harbor concrete structures. The durability analysis program based on Finite Element Method (FEM) was modified adopting the reliability concept to estimate the probability of durability failure. Water-cement ratio in the durability analysis is the most important factor influencing chloride diffusion coefficient, evaporable water, etc. The probability distribution of water-cement ratio was calculated converting standard deviations of compressive strength in Concrete Standard Code to those of water-cement ratio. Based on the Monte Carlo Simulation, the probabilities of penetration depth and durability failure were calculated.

• 한국군사과학기술학회지
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• 제10권2호
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• pp.107-114
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• 2007

This paper describes the Petri Net(PN) model for reliability analysis of fault-tolerant dual Ethernet which Is applied in Naval Combat System. The network for Naval Combat System performs failure detection and auto path recovery by handling redundant path in case of temporary link failure. After studying the behavior of this kind of network, the reliability analysis model is proposed using stochastic Petri Net and continuous-time Markov chains. Finally, the numerical result is analyzed according to changing the failure rate and the recover rate of link.

• International Journal of Reliability and Applications
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• 제14권2호
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• pp.55-70
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• 2013

This paper deals with the Bayesian analysis of the failure data of a repairable mechanical system subject to minimal repairs and periodic overhauls. The effect of overhauls on the reliability of the system is modeled by a proportional age reduction model and the failure process between two successive overhauls is assumed to be 2-parameter Engelhardt-Bain process (2-EBP). Power Law Process (PLP) model has a disadvantage which 2-EBP can overcome. On the basis of the observed data and of a number of suitable prior densities, point and interval estimation of model parameters, as well as quantities of relevant interest are found. Also hypothesis tests on the effectiveness of performed overhauls have been developed using Bayes factor. Sensitivity analysis of improvement parameter is carried out. Finally, a numerical application is used to illustrate the proposed method.

• 산업공학
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• 제10권2호
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• pp.41-50
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• 1997

This paper considers the reliability computation of the network with dependent components and a software system is developed for supporting the reliability analysis and improvement of the system reliability. At first, We propose the common cause failure and load sharing models as the typical models considering the dynamic behaviors of networks with dependent components. Secondly, the algorithm is proposed to obtain the network reliability and reliability importance of component. The software, Delphi, is used to develop the our reliability analysis system.