• International Journal of Internet, Broadcasting and Communication
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• 제13권2호
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• pp.136-144
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• 2021

Railroad Systems, which are national infrastructure industries, cause unexpected property and human damage if they fail to function while operating. Accordingly, railroad facilities supporting the railroad system are areas where high reliability and safety are required. However, it is time for systematic and scientific maintenance to be taken away from the traditional maintenance methods, as the nation's railroad facilities are now aging seriously. The purpose of this study was to secure the safety and reliability of the aging railroad communication facilities and to improve their performance. The research subjects were selected as a precision diagnosis process for railroad communication facilities, and improvement points were derived through detailed precision diagnosis process analysis. It is deemed that this study can contribute based on securing stability, improving reliability, and continuous improvement of railroad communication facilities should be conducted in the operation of the entire railroad system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.994-999
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• 2008

The necessity of diagnosis of the rotating machinery which is widely used in the industry is increasing. Because vibration diagnosis can avoid sudden breakdown of machine and reduce the maintenance costs. In the factory, Air-Compressor which can affect the performance and capacity of output is important machine. Therefore, in this paper, The measuring and analyzing is carried out for air-compressor in order to the factor of resonance and resonance avoidance for air-compressor. The result of diagnosis and solution is discussed in this paper.

• 한국컴퓨터정보학회논문지
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• 제19권5호
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• pp.53-60
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• 2014

최근 IT 기술의 급속한 발전으로 시설물의 설비진단과 관련된 융합 기술의 발전이 가속화되어 가고 있으며, 설계에서 유지, 보수 단계에 이르는 모든 관련 정보를 효율적으로 처리하고 관리할 수 있는 기법에 대한 연구가 요구되고 있다. 본 논문에서는 IT융합기술을 기반으로 설비 진단 및 시설물에 대한 복합정보를 효율적으로 처리하는 처리기법을 제안하고 실시간 복합정보 관리시스템을 설계하였다. 제안된 시스템의 성능을 평가하기 위해 특정 시설물을 대상으로 실시간 관리시스템을 설계하였으며, 결과를 분석하여 제안된 기법의 성능이 우수함을 입증하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제50권4호
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• pp.192-200
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• 2001

As the high density memory is widely used in the various applications, the need for reproduction of memory is increased. In this paper we propose an efficient fault diagnosis algorithm of linear order O(n) that enables the reproduction of memory. The new algorithm can distinguish various fault models and identify all the cells related to the faults. In addition, a new BIST architecture for fault diagnosis is developed. Using the new algorithm, fault diagnosis can be performed efficiently. And the performance evaluation with previous approaches proves the efficiency of the new algorithm.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.216-221
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• 2004

This paper describes a fault detection and fault handling algorithm to be used in a longitudinal vehicle cruise control systems. The fault diagnosis system consists of two structures to generate proper residuals and to find that which component has a fault. A systematic design of the fault diagnosis system using model-based techniques is presented. A linear observer is used to create a set of signals sensitive to faults in a radar sensor. The fault handling system consists of two structures to compensate for faults and degraded system performance. Simulation results show that the algorithm is effective for a fault diagnosis and handling in a longitudinal vehicle cruise control system.

• 한국자동차공학회논문집
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• 제12권1호
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• pp.215-215
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• 2004

This paper describes a fault detection and fault handling algorithm to be used in a longitudinal vehicle cruise control systems. The fault diagnosis system consists of two structures to generate proper residuals and to find that which component has a fault. A systematic design of the fault diagnosis system using model-based techniques is presented. A linear observer is used to create a set of signals sensitive to faults in a radar sensor. The fault handling system consists of two structures to compensate for faults and degraded system performance. Simulation results show that the algorithm is effective for a fault diagnosis and handling in a longitudinal vehicle cruise control system.

• 전력전자학회논문지
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• 제16권2호
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• pp.191-198
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• 2011

본 논문에서는 영구자석 동기전동기 구동용 인버터 스위치에서 개방성 고장이 발생하여도 구동 성능을 유지하기 위한 고장진단 기법이 제안 되었다. 제안한 고장진단 기법은 확장형 칼만필터에 의해 실시간으로 추정된 고정자 저항이 개방성 고장발생 시 고장발생 위치에 따라서 다르게 추정되는 것을 이용하여 고장을 진단한다. 고장진단을 위한 제어 알고리즘을 별도의 하드웨어 구성없이 기존의 제어 프로그램에 추가함으로써 비용을 저감 시킬 수 있으며 추정된 고정자 저항은 상수 변동에 영향을 받는 제어기의 전동기 상수로 사용함으로써 제어 성능을 향상 시킬 수 있다. 제안한 고장진단 기법의 타당성은 시뮬레이션과 실험을 통하여 검증하였다.

• 설비공학논문집
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• 제17권1호
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• pp.47-55
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• 2005

An experimental study has been peformed to develop a scheme for fault detection and diagnosis(FDD) in a vapor compression refrigeration system. This study is to analyze fault effect on the system performance and to find efficient diagnosis rules for easy determination of abnormal system operation. The refrigeration system was operated with a variable speed compressor to modulate cooling capacity. The FDD system was designed to consider transient load conditions. Four major faults were considered, and each fault was detected over wide operating load range by separating the system response to the load change. Rule-based method was used to diagnose and classify the system faults. From the experimental results, COP degradation due to the faults in a variable speed system is severer than that in a constant speed system. The method developed in this study can be used in the fault detection of refrigeration systems with a variable speed compressor.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권4호
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• pp.279-284
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• 2007

Nowadays, due to development of automatic control devices and various sensors, one operator can freely handle several remote plants and processes. Automatic diagnosis and warning systems have been adopted in various fields, in order to prepare an operator's absence for patrolling plants. In this paper, a Bayesian networks based on-line diagnosis system is proposed for a wastewater treatment process. Especially, the suggested system is included learning structure, which can continuosly update conditional probabilities in the networks. To evaluate performance of proposed model, we made a lab-scale five-stage step-feed enhanced biological phosphorous removal process plant and applied on-line diagnosis system to this plant in the summer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.2041_2042
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• 2009

The diagnostic/prognostic problems for condition based maintenance or Prognostics and Health Management has been used. Primary objectives of diagnosis/prognosis are maximizing system availability and minimizing downtime from fault isolation through more effective troubleshooting efforts. Diagnosis aims to detect the onset of failures to improve system performance and reduce life cycle cost by reducing the failure time. The prognosis can reduce operational and support total ownership cost and improve safety of machinery and complex systems. In this Paper, a fault diagnosis methodology has been described using a monopropellant propulsion system model as a test bench.