• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 추계학술대회 논문집 전력기술부문
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• pp.296-298
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• 2008

Currently SCADA System faces various fault situation. Operator must recognize all fault state and management plans. But it is not easy to recognize all category and acquired error data. So it is needed that automatic fault estimation. Automatic fault estimation is possible to data flow control. Data flow control method is two type. One is alarm processing and the other one is topology processing. This paper provide two type processing method in SCADA data flow control.

• 정보보호학회논문지
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• 제20권6호
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• pp.3-13
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• 2010

차분오류주입공격(Differential Fault Analysis, DFA)은 블록 암호를 분석하는 가장 효과적인 부채널 공격(Side-Channel Attacks, SCAs) 방법 중 하나로 알려져 있다. 본 논문에서는 DES (Data Encryption Standard)에 대한 새로운 DFA 방법에 대하여 제안한다. DES에 대한 DFA 방법은 Biham과 Shamir에 의하여 처음으로 제안된 이후, 2009년 Rivain에 의하여 DES의 중간 라운드 (9~12 라운드)에 대한 DFA 방법에 이르기 까지 많은 DFA 방법이 소개되었다. 하지만 기존의 DES에 대한 DFA 방법은 암호화 (또는 복호화)과정에 오류를 주입하는 공격방법임에 비해 본 논문에서 제안하는 DES에 대한 DFA 방법은 DES의 키 생성과정에 오류를 주입하여 분석하는 방법을 처음으로 제안한다. 제안하는 DFA 방법은 기존의 방법들에서 사용하는 오류 모델을 포괄하는 오류 모델을 사용하고 더 척은 오류의 개수로 공격이 가능하다.

• 대한안전경영과학회지
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• 제22권1호
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• pp.15-21
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• 2020

Industrial Motors diagnostic equipment is highly dependent on the automation system, so if there are defects in the automation equipment, it can only rely on the operator's intuitive judgment.To help with intuitive judgment, Park's Vactor Approach(PVA) represents the current signal as a pattern of circles, so it can tell if a fault occurs when the circle is distorted. However, the failure to judge the degree of distortion of the circle pattern is the basis of the fault, so it will face difficulties. In this paper, in order to compare the faults of PVA, the period of d-axis current of PVA pulsation was mastered, so that two phase differences occurred in the same signal source. Through experiments, it is confirmed that this is a 90 degree cross formation of PVA, which is convenient for judging from the vision that there is no fault, thus helping the operator to make intuitive judgment.

• 대한전기학회논문지:전력기술부문A
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• 제49권10호
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• pp.516-523
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• 2000

In this paper, intelligent methods using digital protective relay in power supervisory control system is developed in order to protect power systems by means of timely fault detection and diagnosis during operation for induction motor which has various load environments and capacities in power systems. The spectrum pattern of input currents was used to monitor to state of induction motors, and by clustering the spectrum pattern of input currents, the newly occurrence of spectrums pattern caused by faults were detected. For diagnosis of the fault detected, the fuzzy fault tree was derived, and the fuzzy relation equation representing the relation between an induction motor fault and each fault type, was solved. The solution of the fuzzy relation equation shows the possibility of each fault's occurring. The results obtained are summarized as follows: 1) The test result on the basis of KEMC1120 and IEC60255, show that the operation time error of the digital motor protective relay is improved within ${\pm}5%$. 2) Using clustering algorithm by unsupervisory learning, an on-line fault detection method, not affected by the characteristics of loads and rates, was implemented, and the degree of dependency by experts during fault detection was reduced. 3) With the fuzzy fault tree, fault diagnosis process became systematic and expandable to the whole system, and the diagnosis for sub-systems can be made as an object-oriented module.

• 한국시뮬레이션학회논문지
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• 제12권2호
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• pp.55-62
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• 2003

The explosive Increase of wireless networks and the advancement of mobile devices lead to the expansion of mobile environment. In accordance with the development of mobile environment, the need to use mobile database is increased sharply, and also it accompanies the related problems. The current mobile database system is based on the centralized method from which a synchronized server manages multiple mobile database management system to synchronize. From this mobile system architecture, several kinds of problems can be detected such as the management of synchronization issues between mobile databases and the transaction management issues. Furthermore, the current mobile database management system does not consider any solution on the fault tolerance. To solve those problems, this paper proposes the mobile agent-based mobile database management system. The proposed system provide high confidence and efficiency by enhancing the network efficiency and fault tolerance through the mobile grouping.

• 한국항행학회논문지
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• 제14권1호
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• pp.74-79
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• 2010

본 논문은 FRA(Fault Recovery Agent)의 설계와 구축을 기반으로 네스티드 세션 관리에 대해서 설명한다. FRA는 산업 안전 환경에서 멀티미디어 원격 제어를 위한 소프트웨어 오류를 복구하기에 적합한 에이전트이다. 본 논문에서는 네스티드 세션 구조를 통헤서 신뢰성을 향상시키는 방법에 대해서 기술한다.

• 대한안전경영과학회지
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• 제4권1호
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• pp.37-47
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• 2002

Risk analysis is a formal deductive procedure for determining combinations of component failures and human errors that could result in the occurrence of specified undesired events at the system level. This method can be used to analyze the vast majority of industrial system reliability problems. This study deals with the application of knowledge-engineering and a methodology for the assessment ＆ measurement of reliability, availability, maintainability, and safety of industrial systems using FTA(fault tree analysis), A fuzzy methodology for fault-tree evaluation seems to be an alternative solution to overcome the drawbacks of the conventional approach (insufficient Information concerning the relative frequencies of hazard events). To improve the quality of results, the membership functions must be approximated based on heuristic considerations, The purpose of this study is to describe the knowledge engineering approach, directed to integrate the various sources of knowledge involved in a FTA.

• 반도체디스플레이기술학회지
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• 제9권4호
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• pp.93-97
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• 2010

Fast incipient fault diagnosis is becoming one of the key requirements for economical and optimal process operation management in high-tech industries. Artificial neural networks have been used to detect faults for a number of years and shown to be highly successful in this application area. This paper presents a novel test technique for fault detection and classification for module process of TFT-LCD manufacture using support vector machines (SVMs). In order to evaluate SVMs, this paper examines the performance of the proposed method by comparing it with that of multilayer perception, one of the artificial neural network techniques, based on real benchmarking data.

• 대한안전경영과학회지
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• 제3권2호
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• pp.113-121
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• 2001

Today, facilities are composed of many complex components or parts. Because of this characteristics, the frequency of failures is decreasing, but the strength of failures is increasing; therefore, the failure analysis about many complex components or parts was needed. In the former research about Fault Tree Analysis, failure data of similar facilities have been used for forecasting about target system or components, but in case that the system or components for forecasting failure is new or qualitative and quantitative data are given simultaneously, there are many difficulty in using Fault Tree Analysis with this incorrect failure data. Therefore, this paper deal with the Fault Tree Analysis method which be applied with Fuzzy theory in above case. In case that , therefore, if there is no the correct failure data, it is represented a system or components as qualitative variable. subsequently, it converted to the quantitative value using fuzzy theory, and the values used as the value for failure forecast.

• Journal of Astronomy and Space Sciences
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• 제15권2호
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• pp.499-508
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• 1998

다목적 실용위성 관계시스템의 SOS(Satelite Operations Subsystem) 서브시스템은 위성에서 보내온 원격측정 데이터를 처리하여 위성의 상태를 감시하고 위성으로 원격명령을 전송하는 업무를 수행한다. 본 논문에서는 SOS 서브시스템의 신뢰성 및 가용성을 향상시키기 위하여 하드웨어와 소프트웨어를 이중화하여 데이터 손실을 최소화하도록 설계한 SOS의 동족 고장관리(dynamic fault management) 기법에 대하여 기술하였다. 또한 구현의 정당성을 확인하기 위한 성능 시험 방법을 제시하였으며 그에 대한 결과를 분석하였다.