• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.297-298
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• 2010

• Journal of Applied Reliability
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• v.11 no.4
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• pp.371-385
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• 2011

Because consumer mostly utilizes company test standard, supplier spends burden of expenses on building test equipments and managing expert manpower to fulfill consumer's various tests. Therefore, it is urgent to standardize test assessment which has a bond of sympathy between consumer and supplier and evaluates reliability of their products. This study develops reliability assessment standard which is composed of 12 test items considering international and domestic test standards, company internal test standards of consumer companies and field conditions. Also this study introduces overall technical procedure on accelerated test with no failure which is used for the main technology of reliability assessment. To verify effectiveness of reliability assessment, the test results are herein analyzed through building the test equipments and performing the test items.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.379-384
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• 2005

신뢰성 보증을 위한 인증시험(reliability qualification test)이나 수락시험(reliability acceptance test)에 있어서 가장 널리 사용되는 시험방식 중의 하나가 무고장 시험방식(zero-failure test)이다. 무고장 시험방식이 선호되는 이유는 요구수명을 주어진 신뢰수준으로 보장하는 시험방식들 중에서 적용이 비교적 수월하며 상대적으로 시험기간이나 시료수를 줄일 수 있다는 점 때문이다. 그러나 무고장 시험의 경우, 시험을 의뢰하는 입장에서는 고장이 하나라도 발생하면 불합격 된다는 부담감을 가질 수 있으며 생산자 위험이 커진다는 단점도 가지고 있다. 본 연구에서는 이러한 문제를 보완한 2단계 시험방식을 설계, 제안하고 시험시간, OC곡선 등 시험방식의 특성을 무고장 시험방식과 비교, 분석하였다.

• Journal of Applied Reliability
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• v.17 no.4
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• pp.343-354
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• 2017

Purpose: This paper evaluates the reliability of tapered grid couplings and presents test results through performance and life tests. Methods: The performance and life test method were presented by analyzing the failure modes for the tapered grid coupling. Zero failure test time was calculated to evaluate the reliability of tapered grid couplings and the test was performed under accelerated conditions. The nondestructive test and wear analysis using weighing were also carried out to check the failure modes of the field conditions. Conclusion: This study can be provided to improve the product reliability through failure analysis of a tapered grid coupling. The performance test results of before and after the accelerated life test were presented to confirm the improved reliability of the tapered grid coupling.

• Journal of Drive and Control
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• v.15 no.4
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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.

• Journal of Power System Engineering
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• v.16 no.2
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• pp.43-48
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• 2012

Generally accelerated life test is well known as one method to reduce reliability qualification test period. This test is conducted under the higher stress condition than normal condition. So it can save the test time by calculating the acceleration factor from the relationship between the worst stress condition and normal condition. This paper investigates the worst stress condition for the accelerated life test to increase the acceleration factor. Especially, we focused on the method to obtain effective acceleration factors under the worst stress condition. Moreover, we considered how to decide the worst stress condition by looking for the operating limit of this system. The acceleration factor can be estimated from the ratio of the kinematic viscosity in the normal condition and the worst stress condition, the lowest temperature, by using Arrhenius relationship. Through some experiments for a refrigerator's compressor, we were able to confirm how to increase acceleration factors and how to reduce the reliability qualification test period with minimum samples.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3889-3894
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• 2012

The platform of railroad station for domestic passenger train has been operated at two categories like the platforms if low level(500mm, mainline) and high level(1,135mm, metropolitan subway line). To operate both metropolitan subway line and mainline railroad safely, it is essential to develop the doorstep equipment of railway vehicle regardless of low and high level platforms. On the other hand, the domestic test standard at durability and reliability of doorstep equipment has not been existed until now. This study aims at the development on doorstep equipment of telescopic sliding type for low and high level platforms. Durability analysis with VPD(Virtual Product Development) techniques are performed and the durability standard & qualification life through the rig test during no failure test time is examined in accordance with reliability qualification test.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.140-145
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• 2014

The globally used PV qualification tests and reports the pass/fail only. Therefore, the reliability of new PV materials and parts can't be compared quantitatively with the reliability of the PV parts and materials in the market. Global PV materials and parts companies test and compare their materials, parts, and modules using the failure-to-test (FTT). However, it takes a long accelerated stress test (AST) until failure. It also needs to test the new and existing materials and parts. Therefore, it requires excessive equipment time and cost. In order to reduce the time and cost, a new reliability enhancement methodology has been developed. It tests the PV materials, parts, and modules in the global market and stores them in the PV reliability database. It reduces the time and cost of the comparison and enhancement of PV reliability. An example of the reliability enhancement of the PV encapsulant, EVA is presented.

• Journal of Convergence for Information Technology
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• v.10 no.7
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• pp.240-248
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• 2020

This study compares and analyzes the tasks and evaluation methods of national technically qualified Skin Esthetic through systematic literature review of prior studies on qualification tests for Skin Esthetic qualification and process evaluation types that have been reorganized based on NCS. The national technical qualification is based on the ability to work through memorization-oriented theoretical tests and simple repetition of functions, and the Qualified qualification is relatively short in the period of test execution, and the reliability of its internal evaluation at the enforcement agency continues to be reduced. In the future, national technical qualification require innovation in the qualification system to reflect skilled demand at industrial sites, and course-based qualification for require supplementation and improvement of education and training courses so that they can learn skilled skills at the site.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.263-271
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• 2016

Purpose: A slurry pump for flue gas desulfurization system performs a role that discharges the slurry of a plaster shape in a thermal power plant. Since a slurry pump transfers the slurry by the centrifugal force, it has the friction wear in the impeller and liner because of the slurry. Methods: In this study, failure analysis and test evaluation on the slurry pump have been proposed and the process that reliability of the product improves through design improvement has been presented. And failure cause of typical failure case has been investigated and improvement design has been presented. Results: Reliability improvement is established by analysis of the test results of before and after acceleration test. Conclusion: This study can be provided to improve the product reliability through failure analysis of a slurry pump.