• 한국항공운항학회지
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• 제21권4호
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• pp.27-33
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• 2013

In this study, the FMEA and FTA for reliability analysis of hybrid rocket motor are performed, that was designed in the Hybrid Rocket Propulsion Laboratory of Korea Aerospace University. In order to carry out these analyses the structure of the hybrid rocket motor is hierarchically divided into 36 parts down to the component level and FMEA is carried out with 72 failure modes. Reliability is assessed based on the FMEA, and the results are used in the FTA to evaluate the overall system reliability. In the FMEA, the relationship between the cause and failure modes, effects and their risk priorities are evaluated qualitatively. 27 failure modes are chosen as those with the critical severity that should be improved with priority. As a result of the FMEA / FTA study, a series of design or material changes are made for the improvement of reliability.

• 대한영양사협회학술지
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• 제21권1호
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• pp.25-36
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• 2015

In this study, we attempted to improve hospital food delivery service quality and customer satisfaction by using FMEA (Failure Mode and Effect Analysis), which is applied to the quality control of products in manufacturing plants. Subjective food delivery service quality improvement was judged based on a 5-point likert scale. Traditional FMEA uses an RPN (Risk priority number) to evaluate the risk level of a component or process. The RPN index was determined by calculating the product of severity, occurrence, and detection indexes. In our results, total RPN value (P<0.01) significantly decreased after FMEA introduction, whereas customer satisfaction (P<0.001) and food delivery service quality (P<0.001) significantly increased. Specifically, foodservice errors (P<0.01) and loss cost (P<0.01) were significantly improved by FMEA introduction. Taken together, we suggest that FMEA reduces critical activities and errors in foodservice delivery caused by simple priority selection.

• 품질경영학회지
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• 제42권1호
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• pp.43-61
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• 2014

Purpose: This study identifies preventive measures for VOC management by analyzing the causes and effects of factors that contribute to high risk service failure using FMEA on KORAIL VOC data. Methods: Two research methods were used. First, a Risk Priority Number (RPN) was assigned to each KORAIL VOC based on Failure Mode and Effect Analysis (FMEA). Second, multiple regression analysis was run with RPN factors that include severity, occurrence, and detection as the independent variables and customer dissatisfaction as the dependent variable. Results: Multiple regression analysis showed that RPN factors including severity, occurrence, and detection had significantly positive relationship with customer dissatisfaction. Based on these results, an FMEA was performed on VOC categories with high RPN for railroad stations including platform, ticketing, ticket verification, parking, and escalator, and VOC categories with high RPN for trains including entrance doors, cafes, air quality, announcement, and ticket verification. Conclusion: This study has practical implications to service failure management. A priority order using FMEA was established for the list of customer dissatisfactions that should be addressed to actively manage service failure, and strategies for tackling this priority list are offered.

• 한국정보과학회논문지:소프트웨어및응용
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• 제33권7호
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• pp.605-614
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• 2006

성공적인 소프트웨어 개발은 QCD에 의해 결정되며, 그 중 Quality는 Cost와 Delivery를 결정하는 핵심요소이기도 하다. 그리고 소프트웨어의 규모와 복잡도가 증가함에 따라 quality의 조기 확보의 중요성이 점차 커지고 있다. 이러한 관점에서 개발 후 결함을 찾아내고 수정하는 것보다 결함예방을 위해 더 많은 노력을 기울여야 할 것이다. 결함 예방을 위해서는 peer review, testing과 같은 결함 식별활동과 함께 기존에 발생된 defect 에 대한 분석을 통해 발생 가능한 결함의 주업을 차단하는 활동이 필요하며, 이를 위해 기존의 품질 데이타의 조직화 및 활용이 필요하다. 소프트웨어의 품질 예방을 위한 방법으로 system safety 확보를 위해 사용되고 있는 FMEA를 활용할 수 있다. SW-FMEA(Software Fault Mode Effect Analysis)는 예측을 통해 결함을 예방하는 방법으로, 기존에는 요구사항 분석 및 설계 시 많이 활용되어 왔다 이러한 SW-FMEA는 개발 활동을 통해 측정되는 정보를 활용하여, 분석, 설계, 나아가 peer review나 testing 둥 개발 및 관리 활동에 적용하여 결함예방 (defect prevention) 의 수단으로 활용 할 수 있다. 본 논문에서는 기존에 시스템 분석, 설계에 focusing된 SW-FMEA를 변형하여 product 결합뿐 아니라, 개발과정 중 발생할 수 있는 fault를 줄일 수 있는 결함 예방 model을 제안한다.

• 한국산학기술학회논문지
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• 제22권2호
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• pp.76-84
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• 2021

품질보증활동은 양산단계에서 위험 식별을 기반으로 품질에 영향을 주는 인자를 확인할 수 있다. 위험 식별은 고장 분석을 통해 이루어지며, 회전익 항공기 착륙장치에 대한 고장 분석 방법은 고장 유형 영향 분석(FMEA)으로 선정하였다. FMEA는 고장 유형에 대해서 심각도, 발생도, 검출도에 대한 정보를 결합하여 품질에 영향을 미치는 인자를 확인하는 방법이다. FMEA 결과는 위험도를 통해 고장 우선순위를 결정한다. 하지만 심각도, 발생도, 검출도에 대한 중요도는 동일하게 구성된다. Dempster-Shafer 증거 이론은 경험과 주관이 반영된 의견에 대해서 불확실성 분석을 수행한다. 또한, Dempster-Shafer 증거 이론은 믿음 함수와 개연성 함수를 구성할 수 있으며, 믿음 함수와 개연성 함수를 통해 가설의 믿음 정도, 신뢰도를 확인할 수 있다. 회전익 항공기 착륙장치는 이륙 및 착륙 시 충격을 받는 구성품으로, 양산단계에서 고장 유형을 관리하는 것이 중요하다. 본 논문에서는 회전익 항공기 착륙장치의 고장 유형에 대한 위험도 분석을 위해 Dempster-Shafer 증거 이론을 이용한 FMEA를 제안하고, 고장 우선순위를 결정한다. 결과는 믿음 함수 및 개연성 함수 곡선을 통해 도출한다.

• 한국안전학회지
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• 제33권3호
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• pp.83-91
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• 2018

This paper suggests a weibull time delay model to evaluate failure risks in FMEA(failure modes and effects analysis). Assuming three types of loss functions for delayed time in failure cause detection, the risk of each failure cause is evaluated as its occurring frequency and expected loss. Since the closed form solution of the risk metric cannot be obtained, a statistical computer software R program is used for numerical calculation. When the occurrence and detection times have a common shape parameter, though, some simple results of mathematical derivation are also available. As an enormous quantity of field data becomes available under recent progress of data acquisition system, the proposed risk metric will provide a more practical and reasonable tool for evaluating the risks of failure causes in FMEA.

• 품질경영학회지
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• 제40권3호
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• pp.306-315
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• 2012

Purpose: To ensure good quality munitions, we require quantitative risk management and optimal risk management of system characteristics. Methods: Failure mode and effects analysis (FMEA) is a widely used technique to assess or to improve reliability of products at early stage of design and development. Traditionally, the prioritization of failures for corrective actions is performed by developing a risk priority number (RPN). Results: This paper reestablishes an effective methodology for prioritization of failure modes in FMEA procedure. Revised evaluation criteria of RPN are devised. Conclusion: To verify the proposed methodology, it is applied to RPN evaluation for K21 infantry combat vehicle.

• 한국멀티미디어학회논문지
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• 제21권9호
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• pp.1099-1109
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• 2018

Most of the automotive electronic systems are equipped with control software. ISO 26262 standard has been published to prevent unreasonable risk due to E/E system malfunction. And many automotive companies apply ISO 26262 for safe series product. In ISO 26262 standard, the product quality improves through deductive and inductive safety analysis in all processes including system and software development phase. However, there are few studies on software safety analysis than systems. In the paper, we study the software FMEA(Failure Mode Effect Analysis) technique for product quality of vehicular embedded software. And we propose an effective guideline of software FMEA as EPB industrial practice.

• 산업경영시스템학회지
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• 제35권3호
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• pp.155-162
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• 2012

This study proposes an integrated approach that uses both a fuzzy service FMEA (failure mode and effect analysis) and HOQ (house of quality) matrix algebra in designing and improving a service system. The fuzzy service FMEA methodology applies the customer satisfaction to the fuzzy RPN model. We fuzzify only the service satisfaction that consist in two failure factors, intangible service and tangible service, to more effectively assess the customer satisfactions on service encounters. Proposed fuzzy service satisfactions with triangle membership function are defuzzified by using the Fuzzy Inference System, and these are eventually identified the ranks on the potential fail points. HOQ matrices are constructed from cause-effect relationships. It is possible for these relationship matrix to find a linear approximation solution on the engineering attributes. Thus, in order to demonstrate how the proposed methods work, practical sample of the A/S part in S Electronic Co. provides for the ranking of the engineering attributes which has been successfully implemented.

• Industrial Engineering and Management Systems
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• 제14권4호
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• pp.379-391
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• 2015

Several risk assessment techniques have been presented and investigated in previous research, focusing mainly on the failure mode and effect analysis (FMEA). FMEA can be employed to determine where failures can occur within industrial systems and to assess the impact of such failures. This research proposes a novel methodology for hazard analysis and risk assessments that integrates FMEA with the bow-tie model. The proposed method has been applied and evaluated in a real industrial process, illustrating the effectiveness of the proposed method. Specifically, the bowtie diagram of the critical equipment in the adopted plant in the case study was built. Safety critical barriers are identified and each of these is assigned to industrial process with an individual responsible. The detection rating to the failure mode and the values of risk priority number (RPN) are calculated. The analysis shows the high values of RPN are 500 and 490 in this process. A global corrective actions are suggested to improve the RPN measure. Further managerial insights have been provided.