• 한국신뢰성학회지:신뢰성응용연구
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• 제14권1호
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• pp.53-57
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• 2014

In the fields of reliability application, the most commonly used test methods for reliability demonstration are zero-failure acceptance tests since they require fewer test samples and less test time compared to other test methods that guarantee the same reliability with a given confidence level. For products with lognormal lifetime distribution, the value of scale parameter is usually assumed to be known in designing reliability demonstration tests. It is important to select correct values of scale parameters to guarantee the specified reliability with given confidence level exactly. The effect of using wrong values of scale parameters in designing reliability demonstration test for products with lognormal lifetime distribution is examined and selecting proper values of scale parameters for conservative reliability demonstration is discussed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.577-581
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• 2009

The fixed duration test has been widely used in the reliability demonstration test for rolling stocks. This article deals with how to design the test statistics, acceptance criteria and the fixed duration of the MTBF(Mean Time Between Failures) demonstration test considering the consumer risk. Numerical examples are given to illustrate the dependence of the consumer risk on the test duration and MTBF requirement.

• 한국신뢰성학회지:신뢰성응용연구
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• 제14권4호
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• pp.220-224
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• 2014

A Bayesian zero-failure reliability demonstration test method for products with Weibull lifetime distribution is presented. Inverted gamma prior distribution for the scale parameter of the Weibull distribution is used to design the Bayesian test plan and selecting a prior distribution using a prior test information is discussed. A test procedure with zero-failure acceptance criterion is developed that guarantee specified reliability of a product with given confidence level. An example is provided to illustrate the use of the developed Bayesian reliability demonstration test method.

• 한국신뢰성학회지:신뢰성응용연구
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• 제13권1호
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• pp.1-10
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• 2013

A Bayesian zero-failure reliability demonstration test method for products with exponential lifetime distribution is presented. Beta prior distribution for reliability of a product is used to design the Bayesian test plan and selecting a prior distribution using a prior test information is discussed. A test procedure with zero-failure acceptance criterion is developed that guarantees specified reliability of a product with given confidence level. An example is provided to illustrate the use of the developed Bayesian reliability demonstration test method.

• 한국과학교육학회지
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• 제22권1호
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• pp.12-21
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• 2002

이 연구의 목적은 정량적 현상제시와 정성적 현상제시를 하였을 때, 중학교 학생들의 갈등 정도를 알아보는 것이다. 연구 대상은 부산광역시 소재의 중학교 2학년 297명 을 대상으로 하였다. 검사 문항은 역학의 작용반작용 문항과 전기의 전구의 불의 밝기를 비교하는 문항을 사용하였고, 인지적 갈등을 측정하는 검사지는 권혁구(1999) 등이 개발한 도구를 사용하였다. 먼저, 정량적 현상제시 집단과 정성적 현상제시 집단의 인지갈등 점수를 비교해 보았다. 그리고 현상제시 후 자신의 선개념을 바꾼 학생들과 고수한 학생들의 갈등 점수를 비교해 보았다. 마지막으로, 선개념의 확신 정도와 갈등 정수와의 상관관계를 비교해보았다. 그 결과를 보면, 첫째, 선개념에서 오답을 선택한 학생들은 정성적 현상제시보다 정량적 현상제시에서 갈등 점수가 높게 나타났으며, 선개념에서 정답을 선택한 학생들은 정량적 현상제시보다 정성적 현상제시에서 갈등 점수가 높게 나타났다. 둘째, 자신의 선개념을 바꾼 학생들이 고수한 학생들에 비해 갈등 점수가 높게 나타났다. 마지막으로, 선개념의 확신정도와 갈등 점수와의 상관관계를 보면, 정량적 현상을 제시한 집단의 학생들 중 선개념에서 오답을 택한 학생들은 정적 상관을 보였고, 선개념에서 정답을 택한 학생들은 부적상관을 보였다. 정성적 집단은 뚜렷한 경향을 보이지 않았다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제13권4호
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• pp.299-307
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• 2013

The value of blood sugar is measured by a personal blood glucose meter which consists of two parts: a glucose strip and a blood glucose meter. A personal blood glucose meter makes use of electric media which are composed of glucose oxidase and electron. This study is to propose a method of reliability demonstration test derived from field data analysis and FMEA(Failure Mode and Effect Analysis). Detailed Conditions for reliability demonstration test are selected from the comparison of various failure mechanisms. The most dominant failure mechanism is wear-out which is caused by strip insertion/extraction. The testing device that can reproduce the failure mechanism of strip insertion/extraction is made to conduct reliability demonstration test. Using the testing device, it is confirmed that target lifetime of selected devices is more than 2 years.

• 한국신뢰성학회지:신뢰성응용연구
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• 제12권1호
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• pp.47-56
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• 2012

Reliability demonstration tests with zero-failure acceptance criterion are most commonly used in the field of reliability application since they require fewer test samples and less test time compared to other test methods that guarantee the same reliability with a given confidence level. For products with lognormal lifetime distribution, an economic zero-failure test plan is developed that minimizes the total cost related to perform a life test to guarantee a specified reliability of a product with a given confidence level. A numerical example is provided to illustrate the use of the proposed test plan.

• 대한산업공학회지
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• 제43권2호
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• pp.147-153
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• 2017

In order to demonstrate a target reliability with a specified confidence level, a new two-stage Bayesian Reliability Demonstration Test (RDT) plans that is known to be more effective than a corresponding single-stage one is proposed and developed by Bayesian framework with beta prior distribution for Weibull life time distribution. A numerical example is provided to illustrate the proposed RDT plans and compared with other non-Bayesian and Bayesian plans. Comparative results show that the proposed Bayesian two-stage plans have some merits in terms of required and expected testing time and probability of acceptance.

• 품질경영학회지
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• 제39권2호
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• pp.313-319
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• 2011

In design verification and process validation stages, reliability demonstration tests(RDT's) are common practice in industry, A new two-stage RDT that is known to be more efficient than a corresponding single-stage one in terms of expected test duration for Weibull distribution is proposed. Zero or one failure two-stage plans to minimize expected test duration under Type I and hybrid censoring subject to satisfying consumer's risk at a specified reliability target are developed and a numerical example is provided to illustrate the proposed two-stage RDT plans and compared with other one- and two-stage plans.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.44-50
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• 2014

There were many flaw issues of reactor vessel head penetration in USA fleets. USNRC issued 10CFR50.55a to implement reactor vessel head penetration ultrasonic examination performance demonstration(PD) in US for enhancement of inspection reliability. After September 2009, all US utilities inspected their RVHP with PD qualified system. Korea Hydro and Nuclear Power Company(KHNP) have developed reactor vessel head penetration performance demonstration system for ultrasonic test to apply for pressurized light-water reactor power plants in accordance with 10CFR50.55a since September 2011. RVHP configuration surveying and analysis, code requirement analysis, and performance demonstration specimen design were performed up to this day. Fingerprinting of manufactured specimen, development of test data management program, development of operation procedure, input of flawed data, and development of final report will be performed for the next step. This paper describes the development status of the performance demonstration system for reactor vessel head penetration ultrasonic examination in Korea.