• 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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.184-190
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• 2009

Recently, the concern for the reliability of railway is increasing, also the study about reliability is being processed at a good pace. However, in case of an existing railway operating it is true that the railway system is being operated without a clear RAM standard. There is not a clear RAM standard about product menual of a city railroad, and there are only basic provisions concerning traction motor which can be called a main equipment. In this paper, we calculated the availability and reliability of subway having MKBSF, MKBF, MTBF, MTTR analyzing accumulated maintenance data about a main equipment of a VVVF direct subway being operated in line #4. By watching the reliability grade of a VVVF subway being operated and manufactured within the country and being applied with the development of a city railway reflected by RAM menual when the new subway is manufactured, and with the basic data of RCM, we'd like to grope the methods which can be improved by operation stability of a city railway.

• 한국신뢰성학회지:신뢰성응용연구
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• 제8권1호
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• pp.39-59
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• 2008

The performance of weapon system, based on the acceleration of advanced scientific technology, has been reinforced to the state of precision, complexion and multi-function. People have given great interest for a long time on its development, acquisition cost and enormous expense of operation/support. Under this environmental situation, this research paper proposes two kinds of implementation that can improve the RAM(Reliability, Availability, Maintainability) on weapon system. The first section is to understand all of the actual states on its reliability, in the acquisition process and to make the improvement for RAM at the milestones on the acquisition steps. The next section is to establish a defense RAM center, which will be closely cooperated with acquisition organization such as Ministry of Defense, DAPA(Defense Acquisition Program Administration), DTaQ(Defense agency for Technology and Quality) and ADD(Agency for Defense Development), etc. and to conclusively improve the RAM of weapon system in South Korea.

• 한국항공운항학회지
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• 제23권4호
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• pp.117-124
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• 2015

RAM (Reliability, Availability and Maintenance) has been applied to design and analysis tools which affects system's operational sustainability and its life cycle cost as RAM-c(2009 DoD). RAM-c plays also an important role to guarantee the system engineering for mission assurance. Reliability is highly related to the probability of system failure. Availability means mission capability or the condition of ready to mission. Maintenance includes both the repair to recover the system in the event of failure/unexpected breakdown and proactive maintenance to prolong the design service life of the system or machinery. It is the purpose that this paper is to analyze and conclude the objective service life of UAV. The more UAV is operated, the less the level of its reliability becomes. Repairing failures and supplying spare parts on time, system reliability could be improved up until the time over target. Applying statistical Weibull distributions, this paper suggests the analysis of the design service life and economic life of UAV based on RAM-c with operational data.

• 품질경영학회지
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• 제39권3호
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• pp.353-364
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• 2011

RAM(Reliability, Availability and Maintainability) is one of the important indicators to show the performance of weapon systems. For analyzing RAM characteristics, RAM simulation is useful and powerful as mathematical techniques. However, it is necessary to build the simulation model to express about the operation environment of weapon systems, and obtain detail input data for reliability and maintainability about the system to get accurate results by RAM simulation. In this paper, we propose a procedure to analyze RAM of the searching system consisting in weapon systems by RAM simulation and we estimate searching system availability by a commercial simulation program, AvSim.

• 한국신뢰성학회지:신뢰성응용연구
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• 제9권3호
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• pp.259-274
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• 2009

Printed circuit boards for RAM are widely used in modern electronics such as computers, artificial satellites and consumer durables. They are exposed to a very diverse environment and consists of many complicated components and therefore needs careful approach to the enhancement and assessment of reliability of the item. In this article reliability standards for PCBs for RAM are established in terms of quality certification tests and failure rate tests.

• JSTS:Journal of Semiconductor Technology and Science
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• 제1권3호
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• pp.141-157
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• 2001

Highly reliable packaged 64kbit ferroelectric memories with $0.8{\;}\mu\textrm{m}$ CMOS ensuring ten-year retention and imprint at 125^{\circ}C$ have been successfully developed. These superior reliabilities have resulted from steady integration schemes free from the degradation, due to layer stress and attacks of process impurities. The resent results of research and development for ferroelectric memories at Hynix Semiconductor Inc. are summarized in this invited paper.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1473-1480
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• 2008

본 연구는 현장 운영데이터 분석을 통한 도시철도차량 도어장치의 RAM(신뢰성, 가용성, 유지보수성) 성능 평가 사례를 다룬다. 이를 위하여 도어장치의 고장을 분류하고 정의하며, 각 고장 범주별 신뢰도를 운영 데이터를 통해 분석한다. 유지보수성 평가를 위해서 유지보수 전문가를 통해 LRU(Line Replaceable Unit)를 분류하고 LRU별 교환시간의 추정하여 도어시스템의 평균수리시간을 추정한다. 도어시스템의 가용도는 분석된 신뢰도 및 유지보수성을 기반으로 분석한다. 본 연구에서 제시하는 도어 시스템의 RAM 평가 사례는 도어시스템의 적절한 RAM 요구조건의 수립과 운영단계의 RAM 성능 향상을 위한 정책 수립으로 이어질 수 있을 것으로 기대된다.

• 한국군사과학기술학회지
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• 제11권6호
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• pp.102-116
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• 2008

In the development stage of weapon system, it is important to analyze RAM(Reliability, Availability and Maintainability) characteristics. RAM simulation is one of the advanced techniques for analyzing RAM to overpass the limit of mathematical techniques. However, it is necessary to obtain correct input data for reliability and maintainability about target and support system to get highly accurate results through RAM simulation. In this study, we propose the technical method to improve the results by defining input data of simulation more correctly based on analyzing effects of RAM characteristics by major factors.

• 한국국방경영분석학회지
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• 제27권1호
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• pp.58-72
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• 2001

This research deals with the weapon system RAM which is the reliability, availability and maintainability for weapon systems. This weapon system RAM is one of very important factors because it is related to the life cycle cost and combat readiness of weapon systems. Therefore, in this research we introduce the weapon system RAM and analyze the problems of weapon system RAM management during system life cycle including acquisition period. Finally we suggest an alternative to improve the weapon system RAM in various agencies which are the department of defense and army headquarter level, etc., in the process of defense acquisition.