• 제어로봇시스템학회논문지
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• 제4권2호
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• pp.264-272
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• 1998

This paper proposes a fault detection and recovery mechanism for a fault-tolerant Mini-MAP system, and provides detailed techniques for its implementation. This paper considers the fault-tolerant Mini-MAP system which has dual layer structure from the LLC sublayer down to the physical layer to cope with the faults of those layers. For a good fault detection, a redundant and hierarchical fault supervision architecture is proposed and its implementation technique for a stable detection operation is provided. Information for the fault location is provided from data reported with a fault detection and obtained by an additional network diagnosis. The faults are recovered by the stand-by sparing method applied for a dual network composed of two equivalent networks. A network switch mechanism is proposed to achieve a reliable and stable network function. A fault-tolerant Mini-MAP system is implemented by applying the proposed fault detection and recovery mechanism.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.952-963
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• 2008

The collection of KTX trainset fault code is made by DEP software. We can improve software function and update data after understanding DEP software function and software structure. For the improvement of trainset function and its performance, the same improvement of performance and structure change as DEP software, which collects and analyzes train's fault information, are required. Accordingly, we made a research for functional strucfure of KTX fault code collection software, STR3F, variable declaration through Script.rxr file and code analysis method and proceeded research for realizing more improved user environment of DEL software and fault analysis method.

• 한국전기전자재료학회논문지
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• 제26권12호
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• pp.904-908
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• 2013

When an abnormal condition occurs due to a fault current at a consumer location where electricity is supplied through a high-capacity and high-$T_c$ superconducting(HTS) cable, the HTS cable would be damaged if there is no appropriate measure to protect it. Therefore, appropriate measures are needed to protect HTS cables. The fault-current-limiting HTS cable that was suggested in this study performs an ideal transport current function in normal operations and plays a role in limiting a fault current in abnormal operation (i.e., when a fault current is applied). It has a structure that facilitated its self-current-limiting ability through device change and reconfiguration in the existing HTS cable without extra switching equipment. To complete this structure, it is essential to investigate about the selection of the superconducting wire. Therefore, in this paper, HTS wire using two types of different stabilization layer is compared and examined the stability and current limiting properties under the existence of a fault current.

• Smart Structures and Systems
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• 제23권4호
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• pp.393-403
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• 2019

Applying more features gives us better accuracy in modeling; however, increasing the inputs causes the curse of dimensions. In this paper, a new structure has been proposed for fault detecting and identifying (FDI) of high-dimensional systems. This structure consist of two structure. The first part includes Auto-Encoders (AE) as Deep Neural Networks (DNNs) to produce feature engineering process and summarize the features. The second part consists of the Local Model Networks (LMNs) with LOcally LInear MOdel Tree (LOLIMOT) algorithm to model outputs (multiple models). The fault detection is based on these multiple models. Hence the residuals generated by comparing the system output and multiple models have been used to alarm the faults. To show the effectiveness of the proposed structure, it is tested on single-shaft industrial gas turbine prototype model. Finally, a brief comparison between the simulated results and several related works is presented and the well performance of the proposed structure has been illustrated.

• 대한전기학회논문지
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• 제41권4호
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• pp.331-338
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• 1992

The application of Connectionist expert system using neural network to fault diagnosis of power system is presented and compared with rule-based expert system. Also, the merits of Connectionist model using neural network is presented. In this paper, the neural network for fault diagnosis is hierarchically composed by 3 neural network classes. The whole power system is divided into subsystems, the neural networks (Class II) which take charge of each subsystem and the neural network (Class III) which connects subsystems are composed. Every section of power system is classified into one of the typical sections which can be applied with same diagnosis rules, as line-section, bus-section, transformer-section. For each typical section, only one neural network (Class I) is composed. As the proposed model has hierarchical structure, the great reduction of learning structure is achieved. With parallel distributed processing, we show the possibility of on-line fault diagnosis.

• 자원환경지질
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• 제32권2호
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• pp.161-167
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• 1999

Electric and electromagnetic surveys were conducted to investigate the deep structure of the Ulsan fault in Ipsil area, south of Kyeongju. On this study, especially high-frequency magnetotelluric method of electromagnetic survey in the frequency range of 10~100,000 Hz was mainly employed to study the deep subsurface configuration. High-frequency MT survey was performed at 70 points of spacing 30~50 m, making 3.8 km survey line. As a survey result, a 2-km-depth 2-D cross-section was achieved. It shows vertical and horizontal subsurface variations of resistivity values. Near-surface layer having low resistivity value becomes thicker eastward up to 800m. There is a steep low resistivity zone in the west side of survey line, and there exists two low resistivity zones dipping west in the east side of survey line. Two low resistivity zones are interpreted to be related to major movement pattern of the Ulsan fault. This suggests that major fault lines are developed on both peripheral sides of the broad fault zone.

• 지구물리
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• 제2권4호
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• pp.259-268
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• 1999

양산단층 북부 지역의 지전기학적 구조를 밝히기 위하여 경주시 부지리와 서악동, 나원리와 양동리 사이 지역에서 전기비저항 탐사를 수행하였다. 경주 남부 지역인 부지리와 서악동 사이에서는 예상 단층선 동쪽에 위치한 파쇄대가 서쪽보다 심부까지 연장되며 남북 방향의 변화는 관찰되지 않는다. 경주 북부 지역인 나원리와 양동리 사이에서는 형산강을 따라 단층파쇄대가 발달하고 있으며, 형산강 서쪽의 비저항구조가 동쪽보다 파쇄대의 영향을 많이 받는 것으로 해석되었다. 호명리에서 수행된 쌍극자-쌍극자 탐사의 영상 단면에서는 양산단층이 수직 운동을 한 단층임을 시사하는 구조가 관찰된다. 경주 남부 및 북부 지역에서의 비저항 구조가 크게 변하지 않는 것으로 미루어 양산단층의 북부구역과 중앙구역의 경계는 본 연구지역의 북부에 위치할 것이라 판단된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.773-778
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• 1990

In this paper, a reliable control system structured with dual CPU modules and dual I/O modules is implemented as a means of achieving a highly reliable fault tolerant control system. For this, faults in the system modules are first examined, and a fault detection technique consisting of self diagnostic, comparison process, and exception processing is applied. Also reliability analysis is conducted for the discrete time Markov model with dual structure. It is shown quantitatively that the reliability is improved in the control system with dual structure in comparison with a system with single module structure.

• 한국컴퓨터정보학회논문지
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• 제10권6호
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• pp.37-46
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• 2005

분산 환경 기반으로 많은 작업이 이뤄지는 상황에서 해당 자원에 대한 신뢰성 제공은 매우 중요하다. 자원 제공자는 서비스의 신뢰성을 제공하기위해 일반적으로 채택되는 유형은 서버 리플리케이션 구조 이다. 해당 서버에는 중복된 객체인 리플리카가 유지하는 구조로 이루어진다. 이러한 리플리케이션 구조에서는 안정된 리플리카의 서비스가 중요하므로, 각 리플리카의 결함 발생을 진단하기 위한 구조가 요구된다. 본 논문에서는 분산 객체 시스템에서 제공하는 리플리케이션 관리 시스템의 풀 모니터링 스타일에서 나타날 수 있는 단점을 극복한 CORBA의 푸쉬 모니터링 스타일 기반 효과적 푸쉬 결함 관리 알고리즘을 제안한다. 제안된 푸쉬 결함 모니터링 스타일의 실험결과 비교 대상 시스템에 비해 장애 검출과 관련한 작업량과 평균 타임아웃 비율 측면에서 가치 있는 결과를 확인 할 수 있었다.

• Smart Structures and Systems
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• 제23권3호
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• pp.279-293
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• 2019

To ensure high quality data being used for data mining or feature extraction in the bridge structural health monitoring (SHM) system, a practical sensor fault diagnosis methodology has been developed based on the similarity of symmetric structure responses. First, the similarity of symmetric response is discussed using field monitoring data from different sensor types. All the sensors are initially paired and sensor faults are then detected pair by pair to achieve the multi-fault diagnosis of sensor systems. To resolve the coupling response issue between structural damage and sensor fault, the similarity for the target zone (where the studied sensor pair is located) is assessed to determine whether the localized structural damage or sensor fault results in the dissimilarity of the studied sensor pair. If the suspected sensor pair is detected with at least one sensor being faulty, field test could be implemented to support the regression analysis based on the monitoring and field test data for sensor fault isolation and reconstruction. Finally, a case study is adopted to demonstrate the effectiveness of the proposed methodology. As a result, Dasarathy's information fusion model is adopted for multi-sensor information fusion. Euclidean distance is selected as the index to assess the similarity. In conclusion, the proposed method is practical for actual engineering which ensures the reliability of further analysis based on monitoring data.