• 산업경영시스템학회지
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• 제42권4호
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• pp.31-38
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• 2019

The purpose of this study is to provide the priority of the front-loading factors in the design stage of the automotive parts development process in order to efficiently and effectively respond to the demands of the car maker (customer). Front-loading is defined as a strategy in order to improve development performance by shifting the identification and solving of design problems to earlier phases of a product development process. Two approaches of the front-loading are project-to-project knowledge transfer and rapid problem solving. For the study, a survey was conducted on the R&D department in the automobile parts company and analyzed by AHP (Analytic Hierarchy Process) method. The result of the survey shows the cost savings is the highest weight in terms of front-loading effect and in terms of front-loading factors, it gives priorities as "the problems of past project" first, "Design Review" second, "CAE (Computer Aided Engineering)" third, "FMEA (Failure Mode and Effects Analysis)" fourth, "benchmarking" and SR (Sourcing of Requirements). The results of the study will be helpful to provide practical value for improving product design of component development.

• 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.

• 대한안전경영과학회지
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• 제2권4호
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• pp.91-102
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• 2000

Nowadays, every kind of system is changed so complex and enormous, it is necessary to assure system reliability, product liability and safety. Fault tree analysis(FTA) is a reliability/safety design analysis technique which starts from consideration of system failure effect, referred to as “top event”, and proceeds by determining how these can be caused by single or combined lower level failures or events. So in fault tree analysis, it is important to find the combination of events which affect system failure. Minimal cut sets(MCS) and minimal path sets(MPS) are used in this process. FTA-I computer program is developed which calculates MCS and MPS in terms of Gw-Basic computer language considering Fussell's algorithm. FTA-II computer program which analyzes importance and function cost of VE consists. of five programs as follows : (l) Structural importance of basic event, (2) Structural probability importance of basic event, (3) Structural criticality importance of basic event, (4) Cost-Failure importance of basic event, (5) VE function cost analysis for importance of basic event. In this study, a method of initiation such as failure, function and cost in FTA is suggested, and especially the priority rank which is calculated by computer-aided decision analysis program developed in this study can be used in decision making determining the most important basic event under various conditions. Also the priority rank can be available for the case which selects system component in FMEA analysis.

• 한국멀티미디어학회논문지
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• 제18권11호
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• pp.1342-1350
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• 2015

Due to rapid development of mobile device technologies, the mobile banking through Internet has become a major service of banking information systems as a security-critical information systems. Recently, lots of mobile banking information systems which handle personal and transaction information have been exposed to security threats in vulnerable security control and management processes, mainly software systems. Therefore, in this paper, we propose a process model for software security improvements in mobile banking information system by application of fault tree analysis(FTA) and failure modes and effects analysis(FMEA) on the most important activities such as 'user authentication' and 'access control' and 'virus detection and control' processes which security control and management of mobile banking information systems are very weak.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2011년도 춘계학술발표대회 논문집
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• pp.319-328
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• 2011

The failure of LCC analysis is recognized as a serious risk for companies in fast-paced business environment. LCC analysis has been mentioned and analyzed only in accounting perspectives, but recently engineering perspectives of LCC analysis based on the execution of appropriate procedures become more important than the accounting perspectives. Especially, the practical use of reliability engineering related methodologies is recognized as a key factor for the LCC analysis. For the practical use of reliability methods, LCC analysis for unexposed problems is a key issue, and utilizing FMEA and FTA techniques is needed to solve the unexposed problems. Reliability, maintainability, availability, and safety should be evaluated by the LCC analysis with the reliability methods, so we study methodologies for the LCC analysis. Present Worth can be calculated by multiplication of Annual Equivalent Cost and PWAF. Reliability engineering related methods are needed for the process of dividing Present Worth into PWAF, and the practical use of reliability methods can improve accuracy of LCC analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1529-1532
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• 2007

Failure Mode, Effects, and Criticality Analysis (FMECA) is an extension of FMEA which includes a criticality analysis. The criticality analysis is used to chart the probability of failure modes against the severity of their consequences. The result highlights failure modes with relatively high probability and severity of consequences, allowing remedial effort to be directed where it will produce the greatest value. However, there are several limitations. Measuring severity of failure consequences is subjective and linguistic. Since The result of FMECA only gives qualitative and quantitative informations, it should be re-analysed to prioritize critical units. Fuzzy set theory has been introduced by Lotfi A. Zadeh (1965). It has extended the classical set theory dramatically. Based on fuzzy set theory, fuzzy logic has been developed employing human reasoning process. IF-THEN fuzzy rule based assessment approach can model the expert's decision logic appropriately. Fault tree analysis (FTA) is one of most common fault modeling techniques. It is widely used in many fields practically. In this paper, a simple fault tree analysis is proposed to measure the severity of components. Fuzzy rule based assessment method interprets linguistic variables for determination of critical unit priorities. An rail-way transforming system is analysed to describe the proposed method.

• 품질경영학회지
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• 제41권3호
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• pp.457-463
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• 2013

Purpose: For effective quality assurance activities, BOM-based quality assurance method is presented. This study introduces various BOM conversions such as Q-BOM, T-BOM, and S-BOM based on M-BOM structure. Methods: Product quality control via Q-BOM manages inspection/audit information, overall supply-chain of product, part requirements, and inventory status. T-BOM manages part traceability, and S-BOM enables statistical control over key process and parts at various hierarchy levels. Results: Quality plan template was developed based on the study results of BOM system including Q-BOM, T-BOM, and S-BOM. Conclusion: Through BOM(Q-BOM, T-BOM, and S-BOM) study and development of quality plan template, more systematic and comprehensive quality management plan is achieved.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.7-18
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• 2005

Over the past twenty years, the maintenance system has been developed and its importance has been increased. For the effective maintenance of the urban transit, we have developed the maintenance system based on the concept of RCM(Reliability Centered Maintenance). RCM analysis is a systematic approach to developing a cost-effective maintenance strategy based on the various components's reliability of the system in question. It is performed according to process that includes the following steps; definition of function and functional failures of the systems, construction of RB D(Reliability Block Diagram), performance of FMEA(Failure Modes & Effects Analysis) and calculation of the reliability index. The final process of RCM is to determine appropriate failure maintenance strategies. This paper aims to define the procedure of maintenace based on the concept of RCM for urban transit. The key for a successful maintenance system is an automated scheduling to the maximum extent possible and timely executions. The developed system issues maintenance plan and repair request based on analyzed data and maintenance experience.

• 한국산학기술학회논문지
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• 제13권10호
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• pp.4762-4767
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• 2012

열차의 위치를 검지하고 열차내연산(DTG)을 위한 각종 열차제어데이터를 차상으로 전송하는 AF궤도회로장치는 단일계로 구성되어 있다. 만약, 고장이 발생할 경우 선로전환기 및 신호기제어가 불가능하여 시스템이 복구되기까지 기관사에 의해 수동으로 열차를 운전하여야 한다. 이 과정에서 인적 오류는 열차지연, 충돌, 탈선 등 치명적인 안전사고 발생요인으로 작용한다. 따라서, 본 논문에서는 고장모드마다 시스템과 열차에 미치는 영향을 분석하였으며, 고장평점 및 고장등급을 계량화하였다. 계량화된 분석결과를 토대로 전원장치 독립설치, 증폭PCB의 결함콘덴서 원인분석 및 교체, 저항자 냉각시스템설치, 작업방법개선을 통해 고장발생건수 감소 및 신뢰성의 척도인 평균고장간격(MTBF)의 증가와 평균복구간격(MTTR)이 감소되었다. 그리고, 지금까지 경험에 의한 유지보수체계를 계량화된 방법에 의해 예측정비를 수행토록 하여 AF 궤도회로에 대한 신뢰성을 향상할 수 있도록 하였다.

• 한국전자통신학회논문지
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• 제10권9호
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• pp.1001-1008
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• 2015

본 논문은 안전 시스템의 구성하는 요소 중 전원 장치에 대한 안전 무결성 목표를 설정하고, 설정된 목표를 달성하기 위한 전원 장치의 구조를 설계하였다. 해당 안전 시스템은 안전 최고 등급인 SIL4(Safety Integrity Level 4)를 목표로 하였으며, 철도 응용 분야의 규격인 IEC 62425에 부합하는 구조 설계 및 변경 프로세스를 정립하여 6단계의 기본 구조 설계 방안을 적용하였다. 본 연구에서는 전원 장치의 고장으로부터 시스템의 안전 무결성을 유지할 수 있는 전원 장치의 구조를 FMEA(Failure Modes and Effect Analysis) 기법을 사용하여 도출하였으며, 해당 결과를 적용한 전원 장치는 안전 시스템에 적용할 수 있다는 것을 제시하였다. 최종적으로 전원 장치 모듈에 대한 고장빈도의 정량적 목표치를 제시하였다.