• Proceedings of the KSR Conference
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• 2011.10a
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• pp.7-13
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• 2011

RAMS is the procedure to maximize the reliability and availability of systems with managing operation rate, the frequency of failure in the system and repair method. Recently, all system life-cycle focusing on RAMS process has been rapidly developing in the field of railway vehicles, for example, applying th reliability management techniques for procurement and disposal of EMU. In particular, global economic recession require to reasonable measures for the EMU maintenance costs under the circumstances therefore, an alternative solution based on RCM(Reliability Centered Maintenance) which is the optimal maintenance method is interested. In this study, the state of being critical of each component and a primary factors was analyzed to improve VVVF inverter of the line 7 EMU by applying FMECA process. Furthermore, this paper showed the impact of connecting between the main and sub system. Based on these data, critical components according to malfunction ratings were classified by screening measures and improvements for each components was summarized.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.328-330
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• 2007

Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. The state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect Maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

• Journal of the Korea Safety Management & Science
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• v.13 no.3
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• pp.45-53
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• 2011

The research proposes seven elimination rules of redundant gates and blocks in Fault Tree Analysis (FTA) and Reliability Block Diagram (RBD). The computational complexity of cut sets and path sets is NP-hard. In order to reduce the complexity of Minimal Cut Set (MCS) and Minimal Path Set (MPS), the paper classifies generation algorithms. Moreover, the study develops six implementation steps which reflect structural importance (SI) and reliability importance (RI) from Reliability Centered Maintenance (RCM) that a priority of using the functional logic among components is to reduce (improve) the system unavailability (or availability). The proposed steps include efficient generation of state structure function by Rare Event Enumeration (REA). Effective use of importance measures, such as SI and ill measures, is presented based on the number and the size of MCS and MPS which is generated from the reference[5] of this paper. In addition, numerical examples are presented for practitioners to obtain the comprehensive understanding of six steps that is proposed in this research.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.500-506
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• 2017

In 2014, ISO 55000s has been enacted and the power plant asset management is becoming a hot issue for all over the world. The asset management system is being developed as a combination of CBM(Condition Based Maintenance) and RCM(Reliability Centered Maintenance). Therefore, the research on the calculation of the failure rate which is the most basic index of RCM is actively carried out. The failure rate calculation has been going on for a long time, and the most widely used probability distribution is the Weibull distribution. In the Weibull distribution, the failure rate function is determined in three types according to the value of the shape parameter. However, the Weibull distribution has a limitation that it is difficult to apply it when the trend of failure rate changes-such as bathtub curves. In this paper, the failure rate is calculated using the mixture Weibull distribution which can appropriately express the change of the shape of the failure rate. Based on these results, we propose the necessity and validity of applying mixture Weibull distribution.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1327-1335
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• 2011

Recently, also in railway vehicles, related products are being designed and manufactured through RAMS activities in order to secure their reliability, availability, maintainability & safety. Subway operators are conducting R&D on various preventive maintenance methods and applying them to the field so as to establish a reliability centered maintenance(RCM) system. In this connection, manufacturers shall carry out R&D based on reliability from the first design stage of development to provide high quality products to subway operators. And operators shall have the products operated properly to their particular operating environment and managed based on the standard maintenance manual. Not only that, but the related field data shall be fed back into the manufacturers to upgrade upcoming products by organic cooperation between manufacturer and operators. However, the mutually beneficial cooperative relationship is not still developed in the domestic railway industry. In terms of methodology for life prediction, this study was intended to analyze field data on relays used for rolling stocks considering operational characteristics in the position of subway operators and predict parts reliability using reliability prediction program from the standpoint of manufacturers as well.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.246-248
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• 2006

This paper presents a visualization application using 3D-graphics for effective maintenance of power equipments. The maintenance algorithm implemented in the application is based on Condition-Based Maintenance (CBM) and Reliability-Centered Maintenance (RCM). The main frame of the developed application was made up based on visual C++ (MFC). In order to develop the interactive 3D application, the WorldToolKit library based on Open GL was used. The developed application can help the power system operators to intuitively recognize the present state and maintenance information of the equipments.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.252-257
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• 1998

국내 원전에 신뢰도 기반 정비(RCM : Reliability Centered Maintenance) 기법을 도입하기 위해 수행하고 있는 영광 1,2호기 시법계통 RCM 분석에서 관련 기기의 고장데이터를 RCM 분석 방법론에 따라 분석하였다. 본 논문에서는 작업의뢰서와 작업보고서 기록내용을 토대로 지배적인 고장모드 및 다빈도 고장발생 기기를 파악하여 고장원인을 분석하였으며, 기기 유형으로 분류하여 고장들을 분석하였다. 분석결과 지배적인 고장모드는 EPRI에서 분류한 고장모드에 모두 포함되었으며, 고장빈도가 높은 기기의 고장원인은 운전환경, 사용유체, 운전형태, 기기 형식 등에 따라 고장메커니즘이 다르게 나타나는 것으로 분석되었다. 기기 유형으로 분류하여 고장모드별로 고장율을 분석한 결과 미국의 Generic Data(IEEE Std 500-1984)와 근소한 차이를 보이거나 약간 낮은 것으로 분석되었으며, 고장율이 높은 기기 유형을 단위 기기별로 세분화하여 분석한 결과 공기구동 조절벨브의 외부누설 고장율은 1.10E-06 이지만 충전유량 조절밸브의 고장율은 1.70E-05로서 약 10배 정도로 고장율이 높은 것으로 분석되었다. 기기별로 세분화한 고장을 분석 결과는 시범계통 RCM 분석시 고장모드 영향분석(FMEA. Failure Mode and Effective Analysis) 단계에서 필수기기를 선정하는 하나의 인자로 활용하였으며, 고장율의 역수로 구한 고장간 평균시간(MTBF:Mean Time Between Failure)은 정비주기 선정시 기초데이터로 활용된다.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.183-191
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• 2009

The purposes of this research are presenting a new business model by introducing USN/ZigBee and measuring productivity using BSC(Balanced scorecard), and becoming a cornerstone by presenting a prototype of ServiceScience which is getting more attention from Industrial Engineering and Management. The new business model consists of development of leak current monitoring sensor using USN/ZigBee and the adoption of RCM(Reliability-Centered Maintenance) using knowledge-based system at current distribution. Additionally, for the measurement of this new model's productivity, ESC is used, and the strategic map and measurement indices are produced. The main contributions of this paper are showing a concrete model of ServiceScience and demonstrating this model can be extended to similar areas like are gas, water etc.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.226-238
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• 2011

RAMS (Reliability, Availability, Maintainability, Safety) study has received far less rigorous analysis in the system performance and integration level, and RCM (Reliability Centered Maintenance) research has been studying to improve the maintenance efficiency in the operational steps based on collected data of real operational cases. This paper analyzes the basic concepts based on KS X ISO/IEC 15288 system life-cycle process in the whole system for the light rail transit construction, and the research suggests an approach to the management process of the applicable main tasks. The paper "Management Process Study to RAMS Application of Light Rail Transit System" introduces Airport Rail cases and guidelines by using RAMS which is the major role in the system engineering technical process of ISO/IEC 15288 (International Organization for Standardization/International Electrotechnical Commission 15288) to apply RAMS in domestic light rail transit efficiently, the aim of this study is to broaden of understanding RAMS.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.609-616
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• 2016

The Passenger Service Equipment(PSE) provide various train operation data such as flag station data. When PSE incur service failures or errors, passengers who use the train feel great inconvenience. In this paper, I have chosen PSE that were important to passengers and have applied Reliability Centered Maintenance(RCM), deviating from the existing perspective that operators have taken to perform RCM. FMEA/FMECA was performed for reliability analysis of the PSE. The highly critical device among the PSE is defined as the Passenger Information Control System(PICS), which is used to control the automatic announcement and signaling board. Through Weibull distribution of the PICS, failure analysis was performed. Based on the analyzed results, I have proposed a solution that will minimize service failure of PICS.