• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.569-576
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• 2017

The electromagnetic valve of pneumatic doors of EMUs has a high failure rate due to air leakage because it supplies air on and off to operate the doors repeatedly. The electromagnetic valve is a very important safety component for which a very high reliability is required because failure makes it impossible to operate the passenger cars. However, domestic urban railway operators maintain electronic valves of the EMU door under a fixed cycle with a spare period according to the full overhaul cycle of the EMU. An improvement of the current maintenance cycle was suggested based on the reliability function and mission reliability. Using the statistical program MINITAB for the operational data of EMU line 6, we analyzed the characteristics of the fault distribution and derived the shape and scale parameters of the reliability function. If we limit the specific reliability probability to under a certain failure rate and calculate its statistical parameters, we can calculate the allowable inspection period with mission reliability. Through this study, we suggested a maintenance period based on RCM (reliability centered-maintenance) to improve the reliability of electromagnetic valves from 68% to 95%.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.1
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• pp.71-78
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• 1993

A Baysian approach is proposed is estimating the mission failure rates by criticalities. A mission failure which occurs according to a Poisson process with unknown rate is assumed to be classified as one of the criticality levels with an unknown probability. We employ the Gamma prior for the mission failure rate and the Dirichlet prior for the criticality probabilities. Posterior distributions of the mission rates by criticalities and predictive distributions of the time to failure are derived.

• ICROS
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• v.17 no.4
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• pp.27-34
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• 2011

고장은 시스템의 하나 이상의 구성 요소에서 비정상적인 출력이 나타나는 현상으로 인명 손실, 임무 실패 등의 비극적인 결과를 야기하게 된다. 따라서 고장대처 문제는 시스템 안전성 향상을 위한 매우 중요한 주제이다. 본 논문에서는 고장대처제어 기법 관련 기술현황과 문제점을 살펴보고, 이어서 네트워크 기반 시스템의 고장대처제어 기법 적용을 통해 현재의 문제점을 해결할 수 있는 가능성을 검토한다. 아울러 고장대처 제어 기법이 전통적인 항공우주 분야뿐 아니라 공장자동화 등 일반적으로 시스템 고장이 인명손상으로 연결되지 않는 것으로 인식되는 산업분야에서도 시스템의 신뢰도, 유지보수 편의성, 제품의 품질 개선 등의 측면에서 매우 유용하게 적용될 수 있음을 소개한다.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.219-220
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• 2018

경찰은 2015년 '범죄피해자 보호 원년'을 선포하고 전국 경찰서에 피해자전담경찰관을 배치하는 등 지속적인 보호조치를 실시하였고, 2018년에는 경찰법과 경찰관직무집행법의 경찰 임무와 경찰관 직무 범위에 '범죄피해자 보호'를 명시해서 범죄피해자 보호를 강화하고 있지만, 강력사건에 피해자전담경찰관이 현장 출동자와 동행하도록하는 등 현재보다 경찰의 범죄피해자 보호제도가 더 확충되어야 하며, 사건의 가해자에 대한 철저한 수사도 필요하다. 경찰은 범죄가 발생하지 않도록 예방하여야 하고, 범죄가 발생한 경우에는 수사 전과정에서 범죄피해자 보호중심으로 수사하여야 국민의 신뢰도 얻고 실체진실발견에도 도움이 될 것이다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.203-206
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• 2010

운전원 수동조치는 원자력발전소 화재시 발전소 안전정지를 달성하고 유지하기 위하여 절차에 따라 주제어실 이외의 장소에서 취하는 운전원의 행위를 말한다. 화재시 운전원 수동조치는 발전소 정상운전 동안의 조치에 비해 더 긴장된 상태에서 정해진 시간내에 임무를 완수하여야 한다는 점 때문에 조치성공 가능성을 확인하기 위하여는 행위의 타당성과 신뢰성이 입증되어야 한다. 운전원 수동조치의 타당성과 신뢰성은 조치의 가용시간, 환경조건 등 10가지의 인자를 고려한 시간분석, 절차 및 훈련, 이행, 입증의 과정을 거쳐서 검증될 수 있다.

• Aerospace Engineering and Technology
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• v.2 no.1
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• pp.44-53
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• 2003

The purpose of reliability prediction is to estimate the basic reliability and basic reliability and mission reliability of system and to make a determination of whether these reliability requirements can be achieved with the proposed design. Also, potential design weakness can be identified through the FMECA process. This technical memo summarizes the KOMPSAT-2 reliability and FMECA analysis results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.535-545
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• 2019

The PBA of ship weapon system should be installed and operated under harsh environmental conditions and so it should be highly reliable to endure the mission profiles during its entire lifetime. In the case of PBA failure during operation, rapid maintenance is highly likely to be difficult due to problems such as supply of parts, which can have a devastating effect on the mission. In order to validate the reliability of PBA, a series of tests are performed with PBA samples, but they require time, testing facilities, samples, expenses and failure analysis if failed. The reliability of PBA is predicted on the basis of specifications such as MIL-HDBK-217F, but this specification does not take into account failure mechanisms for specific design details, environment and usage, interconnects and its characteristics that drive many failures of PBA in the field. Therefore, this study predicts the reliability of PBA using an RPA tool and proposes the RPA methodology as a validation process at the design stage. With RPA, it is now possible to achieve design validation including inherent failure mechanism, identification of weakest link, alternative design options, and test plan development.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.113-118
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• 2021

The guided weapon system should ensure economical operation and user safety. In particular, in the case of guided weapon systems developed in the form of a guaranteed bomb, the standards for maintaining reliability considering the long-term storage environment are presented during the development stage, and an optimized inspection cycle is required to maintain this. This study calculated the reliability through a trend test, fitness test, and distribution analysis using a mathematical model based on the maintenance status and shooting results during the inspection period for OO missiles currently in operation for a long time in the military. Through this, it was applied to the inspection period model (Martinez) set during the development stage to determine if the improved inspection period can be utilized. Finally, by synthesizing the data from these studies, a policy management plan was developed according to the extension of the inspection period. The One-Shot system was operated at the inspection period set when it was developed. The study analyzed the actual failure and maintenance data to reset the efficient inspection period.

• Journal of Convergence for Information Technology
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• v.10 no.10
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• pp.123-127
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• 2020

In order to obtain the overall fire line information of medium and large forest fires at night, the ground control system was developed to determine whether forest fires occurred through real-time video clips and to calculate the location of the forest fires determined using the location of drones, angle information of video cameras, and altitude information on the map to reduce the time required for regular video matches obtained after the completion of the mission. To verify the reliability of the developed function, the error distance of the aiming position information of the flight altitude star and the image camera was measured, and the location information within the reliable range was displayed on the map. As the function developed in this paper allows real-time identification of multiple locations of forest fires, it is expected that overall fire line information for the establishment of forest fire extinguishing measures will be obtained more quickly.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.7
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• pp.666-673
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• 2011

To perform effective integration test of avionics equipments, the importance of a setup for integration test environment has been increasing in recently developed aircraft. Especially, the development of integration test equipment is necessary for minimizing the development period and reliability of integration test. This paper treats the model development for optimal working of integration test after analyzing the characteristics of each MEP equipments for Surion(KUH). Models, whose main role is troubleshooting of equipment and simulation for missing equipments, consists of dynamic, behavior, and ICD models depending on the dynamic characteristics. Software test for both unit level and system level are performed to verify the model reliability. By conducting integration test using SIL, it is confirmed that the developed models are suitable for integration function test of the MEP system.