• Journal of Advanced Research in Ocean Engineering
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• v.3 no.3
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• pp.125-135
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• 2017

The paper considers the practical application of the FMEA(Failure Mode and Effect Analysis) method to assess the operational reliability of the LNG(Liquefied Natural Gas) transfer system, which is a potential problem for the connection between the LNG FPSO and LNG carrier. Hazard Identification (HAZID) and Hazard operability (HAZOP) are applied to identify the risks and hazards during the operation of LNG transfer system. The approach is performed for the FMEA to assess the reliability based on the detection of defects typical to LNG transfer system. FTA and FMEA associated with a probabilistic risk database to the operation scenarios are applied to assess the risk. After providing an outline of the safety assessment procedure for the operational problems of system, safety assessment example is presented, providing details on the fault tree of operational accident, safety assessment, and risk measures.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.10 no.1
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• pp.31-36
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• 2014

For decreasing an unexpected shutdown of Nuclear Power Plants, Korea Hydro & Nuclear Power co.(KHNP) has developed Single Point Vulnerability(SPV) of NPPs since 2008. SPV is the equipment that cause reactor shutdown & turbine trip or more than 50% power rundown due to its malfunction. New type Nuclear Power Plants need to develop the SPV list, so performed the SPV selection for about 1 year. To develop this, Failure Mode Effect Analysis(FMEA) methods are used. As results of FMEA analysis, about 700 equipment are selected as SPV. Thereafter those are going to be applied to new type Nuclear Power Plants to enhance equipment reliability.

• Journal of the Korean Society for Railway
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• v.9 no.4 s.35
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• pp.412-418
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• 2006

In this paper we deal with the APARP theory which has been applied for UK railway system and risk assessment method which has been using in the domestic railway system for the safety demonstration. Both techniques are applied to the ATP wayside equipment for interface. Also, fur the applications of each techniques a analysis of the safety activity and a possibility of the application of ALARP theory are evaluated. Finally, we generate requirements of the safety demonstration for the future domestic railway system by way of the analysis of some assumptions and requirement data which can be applied to the risk assessment of ALARP.

• Information and Communications Magazine
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• v.25 no.6
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• pp.3-11
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• 2008

사용 편의나 안전 서비스를 위해 자동차에 내장되는 전자장치(ECU: Electronic Control Unit)는 증가하고 분산 네트워크 구조에서 운영되도록 네트워크 기반 응용 SW는 더욱 복잡해진다. 복잡해지고 분산화되는 ECU에 적용 가능한 응용서비스 개발을 위해 운영체제에서부터 플랫폼 및 응용 SW에 이르기까지 다양한 분야의 산업 표준화가 진행되고 있다. 운영체제 분야에서는 OSEK/VDX, SW 플랫폼 및 응용서비스 분야에서는 AUTOSAR, 응용서비스의 안전과 신뢰성 검증을 위하여 IEC-61508등에 근거하는 FTA(Fault Tree Analysis) 및 FMEA(Failure Mode and Effect Analysis) 등을 SW 분야에서도 반영하는 추세이다. 본 논문에서는 자동차 전자장치에 사용되는 IT기술의 접목 분야별 표준화 동향과 각 국가 및 지역별 추진방향을 살펴본다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.964-967
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• 2013

현재에 시스템의 결함을 분석하는 안전성 분석 기법들이 여러 가지가 있다. 본 논문에서는 많은 결함 분석 기법 중에서 FTA(Fault Tree Analysis)와 FMECA(Failure Modes, Effect and Criticality Analysis)을 통하여 안전성 분석을 하고자 한다. 또한 이 두 가지 기법을 따로 사용하지 않고 전방에서 FTA 분석을 하고 후방에서 FMECA 분석을 수행하는 통합 기법을 제안한다. 이를 통해 각 기법의 단점을 최소화하고 장점을 최대화 하여 안전성 분석의 효율성을 제고하고자 한다.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.3
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• pp.254-263
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• 2012

The survivability of warship is assessed by susceptibility, vulnerability and recoverability. Essentially, a vulnerability assessment is a measure of the effectiveness of a warship to resist hostile weapon effects. Considering the shot line and its penetration effect on the warship, present study introduces the procedural aspects of vulnerability assessments of warship. Present study also considers the prediction of penetration damage to a target caused by the impact of projectiles. It reflects the interaction between the weapon and the target from a perspective of vulnerable area method and COVART model. The shotline and tracing calculation have been directly integrated into the vulnerability assessment method based on the penetration equation empirically obtained. A simplified geometric description of the desired target and specification of a threat type is incorporated with the penetration effect. This study describes how to expand the vulnerable area assessment method to the penetration effect. Finally, an example shows that the proposed method can provide the vulnerability parameters of the warship or its component under threat being hit through tracing the shotline path thereby enabling the vulnerability calculation. In addition, the proposed procedure enabling the calculation of the component's multi-hit vulnerability introduces a propulsion system in dealing with redundant Non-overlapping components.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3221-3223
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• 2007

Recently, nuclear power plant companies have been extending the turbine valve test interval to reduce the potential of the reactor trip accompanied with a turbine valve test and to improve the NPP's economy through the reduction of unexpected plant trip or decreased operation. In these regards, the extension of the test interval for turbine valves was reviewed in detail. The effect on the destructive overspeed probability due to the test interval change of turbine valves is evaluated by Fault Tree Analysis(FTA) method. Even though the test interval of turbine valves is changed from 1 month to 3 months, the analysis result shows that the reliability of turbine over speed protection system meets acceptance criteria of 1.0E-4/yr. This result will be used as the technical basis on the extension of the test interval for turbine valves. In this paper, the propriety of the turbine valve test interval extension is explained through the review on the turbine valve test interval status of turbine overspeed protection system, the analysis on the annual turbine missile frequency and the probability evaluation of the destructive overspeed due to the test interval extension.

• Nuclear Engineering and Technology
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• v.28 no.5
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• pp.440-451
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• 1996

With emphasis on safety, this study addresses for better design condition for the cooling system in a wet-type interim spent fuel storage facility, using a probabilistic safety assessment method. To incorporate the design renovation into the design phase, a simple approach is proposed. By taking the cooling system of a reference design, a fault tree analysis was performed to identify the weak point of the considered system, and then basic factors for design renovation were defined. A total of 21 design alternatives were selected through the combination of the basic factors. Finally, the optimum design alternative for the cooling system is derived by means of the cost and effect analysis based on the estimated cost, system reliability and assumed probabilistic safety criteria. With the assumption that the failure frequency of at-reactor spent fuel cooling system compiles with probabilistic safety criteria for the interim spent fuel cooling system, it was shown that the optimum alternative should have l00% cooling loop redundancy with one pump per cooling loop and a cleanup system installed separately from the main loop. Furthermore, it also should be classified into safety system. The result of this study can be used as a useful basis to identify factors of safety concern and to establish design requirements in the future. The method also can be applied for other nuclear facilities.

• Journal of Technology Innovation
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• v.6 no.2
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• pp.159-177
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• 1998

Although each company is trying to develop an economic analysis model with its own particular style or format, the appropriate method is not yet developed because there are many problems to be solved such as uncertainity of outcomes and intangible benefits of technology. The purpose of tris paper therefore is to suggest an economic analysis methodology, which reflects the complexity and the risk of R&D investment, through a case study on the development of a superconductor fault current limiter. A self-developed Monte Carlo simulation program utilized as a main tool in this paper was very useful for risk analysis of R&D investment which could not be solved in the previous DCF(Discounted Cash Flow) model. We also introduce learning effect to consider the intangible benefits such as Know-How obtained from R&D execution. The expected value and its probability distribution for R&D investment can be obtained by combining the Monte Carlo method with the decision tree approach. This result is helpful in judging the priority and the resource-allocation of R&D projects. It is however necessary to develop more precise model for quantifying the technology stock and the simulation program using the continuous probability distribution in expected values to improve the reliability of economic analysis on R&D projects.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.6
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• pp.894-903
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• 2018

In the case of helicopters, the development of parts technology is rapidly changing, and the complexity is rapidly increasing. Particularly, the surge of various electric and electronic systems is recognized as a problem that is directly related to the safety of the helicopter. Due to these problems, there is a growing interest in reliability evaluation in the face of the problem of confirming and certifying the reliability of parts in the development stage. In this paper, the analysis of the failure mechanism of the wiper system was carried out, and the priority and importance of each failure mode were checked by using the results, and major stress factors were derived and the corresponding acceleration model was selected. Also, the accelerated lifetime test time was calculated according to the life test time, acceleration status and acceleration level of the steady state by using the selected acceleration model and characteristic values.