• 한국철도학회논문집
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• 제9권1호
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• pp.29-35
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• 2006

Trains in LRT(Light Railway Transit) system usually have shorter car length than metro's because of their smaller passensers demand. Therefore it is very likely that the load condition of LRT system in abnormal operation, in case of which trains are in close proximity by system broke or train rescue works, could be worse rather than in normal operation, in spite of rare probability of abnormal operation. In this study, the target reliability indexes of several abnormal operations are estimated in accordance with the occurrence probabilities of each abnormal operation case and the reliability index of normal operation presented by the specification. From the indexes, load factors for the abnormal operation cases are estimated and the safety evaluation is performed for Yong-in LRT project.

• 한국자동차공학회논문집
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• 제21권3호
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• pp.157-164
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• 2013

A damper clutch in automatic transmission systems has some advantages of fuel economy and dynamic performance. Although a damper clutch operation improves a fuel economy of the vehicles, a positive operation of a damper clutch in a low vehicle speed induces abnormal vibration. This paper analyzed one of reasons for abnormal vibration by a damper clutch operation in low engine speed ranges. A simulation model was designed to confirm the effects of a damper clutch operation under unstable regions of an engine. A theoretical analysis was carried out about an engine operation stability. Simulation was conducted to depict abnormal vibration by a damper clutch operation in unstable regions of an engine performance curve. The effects of an engine operation region for abnormal vibration by a damper clutch was investigated according to the range and the slope of unstable regions. As a result of simulations, a damper clutch operation would be better to avoid an engine unstable regions.

• 한국안전학회지
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• 제29권3호
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• pp.129-135
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• 2014

The number of abnormal operation procedures (AOPs) for mitigating a plant abnormal status amounts to about one hundreds for the most of 1000MWe optimized power plant (OPR1000) and it is expected that the number of AOPs would be increased to cope with an abnormal status occurred newly. However, it is not well organized for operators to select a proper AOP from alarms occurred in main control room (MCR) during a plant abnormal status. It may be a burden to operators since the selection of AOP to respond an abnormal status is authorized by operators. When multiple alarms occur in MCR, it would take more time to respond them than a single alarm. To reduce the efforts, various MCR operation support systems have been developed. The purpose of this study was to develop a multi-alarm pattern card to select an appropriate AOP effectively when multiple alarms occurs in a single upper layout (UL) of MCR. It can be applied for an operation support tool as well as an education tool.

• 품질경영학회지
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• 제47권3호
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• pp.417-424
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• 2019

Purpose: In this study, the goal is to analyze this case to prevent the same accidents when using one-shot rifle. Methods: Detailed analysis of damaged parts must first be made in order to determine the cause of the abnormal explosion. The cause of abnormal operation can be determined by analyzing the information of damaged components and the firing mechanism of the weapon step by step. Also we can refer to a statement of shooter, witness and accident scene situation. Based on this theory, cause of abnormal firing can be narrow down. Results: Fracture of pin for fixing firing and latch is cause of abnormal operation of firing. Conclusion: It is deemed that periodic inspection and fundamental improvement of the structure are required to prevent the same accident as this.

• 한국산업융합학회 논문집
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• 제23권5호
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• pp.835-842
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• 2020

This paper considers a method of reproducing abnormal and fault operation for smart monitoring of thrust bearing used in wave power generation system. In order to develop smart monitoring technology, abnormal and failure data of actual equipment are required. However, it is impossible to artificially break down the actual equipment in operation due to safety and cost. To tackle this problem, a test bed that can secure data through reproduction of a faulty operating environment should be developed. Therefore, in this study, test bed that can reproduce each situation was developed and the operation result was analysis after identifying the situation to be reproduced through the failure factor analysis of the thrust bearing.

• 한국가스학회지
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• 제1권1호
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• pp.64-72
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• 1997

화학 플랜트에서의 이상상황 발생시, 안정된 공정으로 복귀시키기 위하여 운전자의 의사결정을 지원하는 goal tree를 합성하는 시스템을 개발하였다. 운전자의 경험적 지식을 바탕으로 발생 가능한 많은 사고들의 특징과 이상의 규모등에 적절하게 대응조치상황을 발견할 수 있도록 지식베이스를 구축하였다. 그리고, 인공지능기법을 이용하여 적용공정에 대한 구체적인 대응조치상황을 생성하였다.

• Journal of Chest Surgery
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• 제19권3호
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• pp.363-373
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• 1986

Even though the pathogenesis is still controversial, electrocardiographic changes after congenital open heart surgery depend on various etiologic factors. Author reviewed 261 cases of congenital open heart surgery patient experienced in the Dept. of Thoracic & Cardiovascular Surgery, Pusan National University Hospital, since July, 1981 to Sept., 1985. The results were summarized as followed: 1. The age distribution was from 3 to 29 years old with mean age 10.8 years. And the most frequent congenital heart defect we had done operation was VSD. 2. Preoperatively, the most frequent ECG finding was abnormal QRS complex and postoperatively the most frequent ECG change was arrhythmia. 3. The most frequent arrhythmia before operation was intraventricular conduction disturbance. 4. Right ventriculotomy incision produced the more frequent abnormal ECG changes postoperatively than right atriotomy or pulmonary arteriotomy. 5. According to the operative technique, outflow patch graft of TOF repair produced the highest frequency of ECG changes after operation, and in comparing simple and patch closure of VSD, the latter was higher frequency of ECG changes, in valvotomy and infundibulectomy of PS, the latter was higher too. 6. The common symptom and signs in abnormally ECG changed patients after operation were palpitation, dyspnea, congestive heart failure and murmur in this order., 7. The longer the time of CPB, the more number of abnormally ECG changed patients had been developed after operation. 8. The most of postoperative ECG changed patients recovered spontaneously or with only medication and were clinically insignificant. And the rest other minor group recovered with temporary pacing. Eight cases out of 261 [3.1%], these with abnormal QRS complex and arrhythmia couldn`t recover in spite of every effort and eventually succumbed.

• 한국기계가공학회지
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• 제18권6호
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• pp.82-90
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• 2019

To reduce emissions of marine pollutants, regulations are being tightened around the world. In the shipbuilding and shipping industries, various countermeasures are being put forward. As there are limits to applying countermeasures to ships already in operation, however, it is necessary for these vessels to use energy efficiently. The sensors installed on ships typically gather a very large amount of data, and thus a big data platform is needed to manage and analyze the data. In this paper, we build a big data analysis platform based on Hadoop and Spark, and we present a method to detect abnormal ship operation using the platform. We also utilize real ship operation data to discuss the data analysis experiment.

• 한국안전학회지
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• 제37권4호
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• pp.28-35
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• 2022

This study is aimed to develop a safety diagnosis system for fire pumps that detects normal and abnormal signals for the stable operation of the system. Hence, the following activities were carried out: first, a threshold value was identified for the normal operation and six abnormal operations (adherence of impeller, absence of water source, separation of pump and motor, run-stop operation, air inflow into the casing, and reverse-phase loss of the power line) reflecting changes in the current, flow and pressure of fire pumps; secondly, based on the identified signals, an algorithm capable of detecting three abnormal signals was developed and in terms of hardware, a current, pressure and flow sensor suitable for the analogue input values of NI-6009 was designed and installed. This combination of the hardware and software is applicable as a diagnosis system to ensure the stable operation of fire pumps.

• 대한토목학회논문집
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• 제32권4B호
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• pp.221-232
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• 2012

본 연구에서는 이상홍수 발생 시 저수지의 안전성을 확보함과 동시에 두 개의 저수지를 효율적으로 연계운영하여 하류의 홍수피해를 줄이기 위한 모형을 개발하였다. 이상홍수 발생 시 저수지 최적연계운영을 위해 선형계획법을 사용하였고, 저수지 운영에서 유입량, 저수지 수위, 유입량의 증감 등의 요소에 포함된 불확실성을 해결하기 위해 퍼지제어기법을 도입하였다. 선형계획법을 이용하여 이상홍수 유입에 따른 저수지 최적연계운영규칙을 찾아내고, 퍼지제어기법을 사용하여 신속하고 정교한 운영이 요구되는 이상홍수 유입상황에 사용할 수 있는 모형을 개발하였다. 본 연구에서는 낙동강 상류에 위치한 안동댐과 임하댐을 대상으로 각 댐의 저수지에 100년 빈도의 홍수와 PMF가 유입될 때 안동시의 계획홍수량을 초과하지 않도록 저수지최적연계운영을 실시하였고, 최적연계운영규칙과 퍼지제어기법을 사용하여 댐 하류지점의 유량과 각 댐별 저류량, 유입량, 유입량의 증감에 따라 방류량을 결정하는 모형을 개발하였다. 개발된 모형은 안동댐과 임하댐의 각 저수지 및 안동시의 유황에 따라 결정되는 224개의 퍼지규칙으로 정리되었으며, GUI를 통해 현재 유황을 입력하면 각 댐의 방류량을 간단히 결정할 수 있다.