• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.2
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• pp.101-108
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• 2001

본 논문에서는 배전선로에서 발생하는 여러 고장유형을 판별하기 위해서 적응형 퍼지추론 시스템을 적용하는 새로운 기법을 제시하였다. 배전선로의 고장과 고장유사현상 데이터를 추출하기 위해서 EMTP를 이용하여 RL부하, 아크로부하, 컨버터부하가 있는 배전계통을 구성하고 여러 형태의 고장과 고장유사현상에 대해 시뮬레이션을 하였다. 이를 통해 얻은 전류 파형으로부터 기본파성분, 영상분전류, 짝수 고조파성분의 합, 홍수 고조파성분의 합, 그리고 비정규 고조파성분의 합의 5개의 입력변수를 추출하고 학습을 통해서 각 입력변수의 소속함수의 소속도를 자동으로 결정하였다. 이 적응형 퍼지추론 시스템을 이용한 기법을 평가하기 위해서 학습시와 다른 고장상황을 모의하여 얻은 데이터와 실증시험 데이터를 이용하였다. 결과적으로 제안한 기법은 배전선로에서 발생하는 고장유형을 빠르고 정확하게 판별할 수 있었다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2089-2090
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• 2011

본 논문에서는 MOF 소손시 비오차 발생으로 인한 전력사용량에 미치는 영향을 분석하기 위해 비오차를 측정하였다. 현재 MOF 고장건수는 전체파급고장의 약 10%이상 발생되고 있으며, 현장 순회시험을 통해 2009년 68건, 2010년 156건을 적출하였다. 이러한 MOF의 고장은 대부분 내부 CT 권선소손에 의해 발생되며, CT의 1차코일 또는 2차코일 단락시 유형별로 실험을 통해 비오차를 분석하였다. 특히 3상 수전고객은 ${\Delta}$-Y결선방식으로 MOF 정상시 불평형 전류는 중성선의 전류가 발생되지 않으나, MOF 이상시 중성선에 이상전류가 발생된다. 따라서 중성선의 이상전류를 측정하여 MOF 이상유무 판정 및 과부족 계량 오차 판정을 하기 위한 자료로 활용하였다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.4
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• pp.325-330
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• 2018

This paper, following the shape parameters of the minimax distribution, describes the special form of the beta distribution, the Minimax distribution, as a function of the shape parameters for the software reliability model based on the non-homogeneous Poisson process. Characteristics and usefulness were discussed. As a result, the case of the shape parameter 1 of Minimax distribution than less than and greate in mean squared error is the smallest, in determination coefficient, appears to be high, the shape parameter 1 of Minimax distribution regard as an efficient model. The estimated determination coefficient of the proposed model is estimated to be more than 95%, which is a useful model in the field of software reliability. Through this study, software design and users can identify the software failure characteristics using mean square error, decision coefficient, and confidence interval can be used as a basic guideline.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1059-1068
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• 2016

The current operation method for the AVC (Automatic Vehicle Classification) equipment does not generate vehicle speed, traffic volume and vehicle type information when part of the sensors has failed. Inefficiency of current methods would not use the collected data from the normal sensor. In this study was conducted research on the calculating method at the traffic volume and vehicle speed in the sensor failure AVC equipment. The failure situation of the sensor was classified into 4 types. Calculating the traffic volume and vehicle speed information for each type, and accuracy of these informations were analyzed. Analysis results, traffic volume was possible to calculate a highly accurate value (accuracy: 100%, 98%, 97%). In the case of speed, the accuracy of the calculated speed value reaches a level that can be accepted sufficiently (RMSE value is less than 16.8). So, using the methodology proposed in this study are expected to be able to increase the operational efficiency of the AVC equipment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.64-70
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• 2018

The development of weapon systems (or components) is hindered by the number of tests due to the limited development period and cost, which reduces the scale of accumulated data related to failures. Nevertheless, because a large amount of failure data and maintenance details during the operational period are managed by computerized data, the cause of failure of weapon systems (or components) can be analyzed using the data. On the other hand, analyzing the failure and maintenance details of various weapon systems is difficult because of the variation among groups and companies, and details of the cause of failure are described as unstructured text data. Fortunately, the recent developments of big data processing technology, machine learning algorithm, and improved HW computation ability have supported major research into various methods for processing the above unstructured data. In this paper, unstructured data related to the failure / maintenance of defense weapon systems (or components) is presented by applying doc2vec, a machine learning technique, to analyze the failure cases.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.2
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• pp.21-25
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• 2013

The system and components for aircraft are required the design data on which the safety requirements are properly reflected for their certification. This paper presents the procedure and results of a safety assessments analysis for the rotorcraft fuel pumps in oder to confirm and verify them. The fuel pumps design assessment must be performed, including a detailed failure analysis to identify all failures that will prevent continued safe flight or safe landing. In order to assess the fuel pumps design safety, not only system safety hazard analysis and but FTA(Fault Tree Analysis) for proofing the safety objective of the fuel pumps are performed. The results of the safety assessment for fuel pumps validate that no single failure or malfunction could result in catastrophic failure or critical accidents of the rotorcraft.

• Journal of Korean Society of Steel Construction
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• v.16 no.4 s.71
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• pp.407-414
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• 2004

Bridges in common use are expected to have more varieties of load in their connected members and bolts than in construction. Faults in connection members or bolts occur so often according to the time flow. One of the purposes of this study is to find out the behavior and structural features of high-tension bolted joints with faults that are very difficult and cost much to find out through experimentation with finite element analysis. Another purpose of this study is to provide sufficient data, estimated experimental results, and the scheme of the test plate for an economical experimental study in the future. Surveys of bridges with a variety of faults and statistical classifications of their faults were performed, as was a finite element analysis of the internal stress and the sliding behavior of standard and defective bridge models. The finite element analysis of the internal stress was performed according to the interval of the bolt, the thickness of the plate, the distance of the edge, the diameter of the bolt, and the expansion of the construction. Furthermore, the analysis explained the sliding behavior of high-tension bolt joints and showed the geometric non-linear against the large deformation, and the boundary non-linear against the non-linear in the contact surface, including the material non-linear, to best explain the exceeding of the yield stress by sliding. A normally bolted high-tension bolt joint and deduction of bolt tension were also analyzed with the finite element analysis of bridge-sliding behavior.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3444-3449
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• 2013

The control module controlling points has become high-tech. but the introduction of relevant company's inspection intervals and methods, and the adoption of the way which is used in relay interlock system became the cause of a failure by excessive and incorrect maintenance. The Human error in failure recovery process can cause vital accidents including train derailment, the points monitoring system could prevent this problem by monitoring points' operation condition in real time. After conducting the changed inspection intervals that applied the results of the criticality of each failure type, MTBF, MTTR, availability, maintainer's opinion, the work became simplified, and, the failure did not occur for 4 consecutive years in contrast to the previous annual average of 11 failures.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.75-76
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• 2008

전력거래소는 전격계통 안정된 운영과 공정한 전력시장 운영을 주요 임무로 하며, 이를 위하여 전국의 80여개의 발전소와 600여개 변전소로부터 발전량, 전압, 조류, 자단기 상태정보 등 다양한 전력계통 자료를 취득하고 있다 전력거래소의 중앙급전소에는 이와 같은 계통자료 취득은 물론 발전량 제어기능을 수행하기 위한 에너지관리시스템(이하 EMS 라 한다)을 운영하고 있으며, 발,변전소에는 현장의 전력설비와 연결되어 계통자료를 취득하여 EMS로 전송하는 원격소장치 (이하 RTU 라한다)를 운영하고 있다. 자료취득 경로는 모든 발전소와 34skv급 이상의 변전소의 경우 EMS와 RTU가 직접 연결되어 자료를 취득하며 154Kv급 이하 변전소는 12개 지역급전소의 자료취득제어시스템(이하 SCADA라 한다)를 경유하여 자료를 취득하고 있다. 전력계통의 대형화와 복잡화에 따라 계통해석기능 자동발전제어기능에 의한 계류운영으로 정보기술에 대한 의존도가 증가하고 있으며, 변동비 반영시장의 개선운영에 따라 공정한 전력시장 운영과 안정된 전력계통 운영을 위해 전력계통 취득자료의 신뢰도가 요구되고 있다. 따라서 EMS를 비롯한 RTU, 통신망 등 전력계통 자료취득 설비의 운영실적을 분석하여 각 시스템별 고장 고장원인 고장유형 등을 고찰하므로써 시스템 성능개선을 위한 설비투자와 운영개선에 반영하고자 한다.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.3
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• pp.303-307
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• 1990

In this paper, the factors of 1680 marine casualties occurred during 1986-1988 are analysed by the Principal Component Analysis. The main results are as follows: 1. Most of marine casualties result from the human factors such as careless operation and insufficient engine maintenance. Engine trouble is main part of accidents and great number of accidents is rated for fishing vessels. 2. Accidents are serious in case of cargo ships, passenger ships and tankers from the point of view of the damage of human life and properties. On the other hand, those are not so serious matter in case of fissing vessels and governmental vessels. 3. Grounding, collision and capsizal mainly result from careless operation, however material defect result in flooding