• 전자공학회논문지CI
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• 제38권6호
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• pp.57-69
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• 2001

전문가 시스템은 인공지능의 한 분야로서 인간의 사고방식을 모방함으로써 다양한 분야에서 야기되는 문제들을 해결해준다. 대부분의 전문가 시스템은 추론엔진과 지식베이스등과 같은 많은 요소들로 구성된다. 특히 전문가 시스템의 성능은 추론엔진의 효율성에 의해 좌우된다 이러한 추론 엔진은 지식베이스가 구축될 때, 가능한한 적은 제약성을 가져야 함은 물론, 다양한 추론 방법을 제공해야 한다는 특정을 갖고 있어야 한다. 이 논문에서는 도메인 지식 표현을 위한 지식스키마와, 추론을 위한 지식구현 기법, 그리고 블랙보드와 추론엔진을 혼합한 지식베이스 엔진을 제안한다. 그리고 제안한 기법들을 이용하여 구축한 중공업 장비 진단 전문가 시스템에 대해서 설명한다. 이 논문에서 연구한 고장진단 지식기반 시스템은 지식기반 시스템 연구분야의 실질적 기반이 될 수 있을 것이다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.1205-1208
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• 2005

By adding user interface to the usual router, an improved functional router is implemented in this paper. Due to the massive amount of spatial data processing, spatial information processing area has been rapidly grown up in recent years based on powerful computer hardware and software development. Spatial index structures are the core engine of geographic information system(GIS). Analyzing and processing of spatial information using GIS has a lot of applications and the number application will be increased in the future. However, study on the under ground is in its infancy due to invisible characteristic of this information. This paper proposes the sub-surface fault detection system using the sub-surface layer information gathered from elastic wave. Detection of sub-surface fault provides very important information to the safety of above and sub-surface man made structures. Development of sub-surface fault detection system will serve as a pre-processing system assisting the interpretation of the geologist.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.706-709
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• 1996

In this paper, an algorithm for PLC(Programmable Logic Controller) fault diagnosis system is proposed and experimentation is conducted with a PLC and a virtual plant. Wrong output backward tracking algorithm is proposed in order to find the external faults of PLC. And query with keywords of the fault systems and specially designed test sequence programs are used. We lay emphasis on the backward tracking algorithm to diagnose the faults of PLC. It is shown experimentally that the proposed algorithm can find the faults which a typical self diagnostics in the-commercially available PLC cannot.

• 한국생산제조학회지
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• 제22권2호
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• pp.287-291
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• 2013

Fault Diagnosis is a process of detecting and isolating faults in a system. On demanding for safety and high reliability systems make it important for some reasons such as economical and environmental incentives. Especially embedded technology and IT technology combined with precise sensing techniques has been doing well developed and applied to fault diagnosis and prognosis in industrial systems like as automotive, ship, heavy industry and aerospace as well. This paper, as an empirical application of diesel engine, presents a method how to get raw data from physical systems, what to consider for successful implementation and which theoretic mathematical models should be applied. In a sense of system level Adaptive Filtering (we call Modified Kalman Filter) and a unit of part level Hidden Markov Process was developed and applied.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.746-748
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• 1997

The parity relation approach for the fault detection and isolation (FDI) of a large diesel engine actuator position servo system is presented. Main purpose of the FDI system is to detect and isolate two important faults, actuator fault and sensor fault, that, if not detected and compensated, degrade the overall system performance. Simulation results are given to show the practical applicability of the FDI scheme.

• International Journal of Aeronautical and Space Sciences
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• 제9권2호
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• pp.64-70
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• 2008

The UAV propulsion system that will be operated for long time at more than 40,000ft altitude should have not only fuel flow minimization but also high reliability and durability. If this UAV propulsion system may have faults, it is not easy to recover the system from the abnormal, and hence an accurate diagnostic technology must be needed to keep the operational reliability. For this purpose, the development of the health monitoring system which can monitor remotely the engine condition should be required. In this study, a fuzzy trend monitoring method for detecting the engine faults including mechanical faults was proposed through analyzing performance trends of measurement data. The trend monitoring is an engine conditioning method which can find engine faults by monitoring important measuring parameters such as fuel flow, exhaust gas temperatures, rotational speeds, vibration and etc. Using engine condition database as an input to be generated by linear regression analysis of real engine instrument data, an application of the fuzzy logic in diagnostics estimated the cause of fault in each component. According to study results. it was confirmed that the proposed trend monitoring method can improve reliability and durability of the propulsion system for a long endurance UAV to be operated at medium altitude.

• 전기학회논문지
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• 제63권3호
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• pp.376-382
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• 2014

E-Actuator is an essential part of an eVGT, it receives the command from the main ECU and controls the vane. An e-Actuator failure can cause an abrupt change in engine output and it may induce an accident. Therefore, it is required to detect anomalies in the e-Actuator in real time to prevent accidents. In this paper, an e-Actuator fault detection method using on-line parameter identification is proposed. To implement on-line fault detection algorithm, many constraints are considered. The test input and sampling rate are selected considering the constraints. And new recursive system identification algorithm is proposed which reduces the memory and MCU power dramatically. The relationship between the identified parameters and real elements such as gears, spring and motor are derived. The fault detection method using the relationship is proposed. The experiments with the real broken gears show the effectiveness of the proposed algorithm. It is expected that the real time fault detection is possible and it can improve the safety of eVGT system.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.178-182
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• 2007

액체로켓엔진시스템 개발 시험 중 발생할 수 있는 각종 이상 징후 발생 시 이를 사전에 감시하고, 비상상황 발생 시 시험대상 엔진과 시험설비를 보호하기 위한 엔진 상태진단 및 비상보호시스템에 대해 살펴보았다. 비상보호시스템의 일반적인 구성과 관련된 주요 기술 고려사항을 검토하였다. 또한, 터보펌프, 가스발생기 및 연소기 등의 엔진 주요 구성품의 개발시험에 적용된 상태진단 및 비상보호시스템에 대한 적용 사례에 대해서도 살펴보았다.

• 항공우주시스템공학회지
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• 제9권4호
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• pp.67-72
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• 2015

The analysis has been performed on the blockage effect at the propellant flow passage in a liquid rocket engine. This simulates an example of emergency situation where flow passage is partially blocked. The analysis method has been validated by predicting the pump head and flow rate within 1% precision against the measured data of turbopump-gas generator coupled test. When the oxidizer passage is reduced it is predicted that the mixture ratio decreases, the oxidizer pump head increases and the gas generator pressure increases. When the fuel passage is reduced it is predicted that the mixture ratio increases, fuel flow rate decreases and the fuel pump head increases.

• 대한전기학회논문지:전력기술부문A
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• 제53권12호
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• pp.637-644
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• 2004

This paper proposes an expert system with the knowledge learning capability which can enhance the safety and effectiveness of substation operation in the automated substation as well as existing substation by inferring multiple events such as main transformer fault, busbar fault and main transformer work schedule under multiple inference mode and multiple objective mode and by considering totally the switch status and the main transformer operating constraints. Especially inference mode includes the local minimum tree search method and pattern recognition method to enhance the performance of real-time bus reconfiguration strategy. The inference engine of the expert system consists of intuitive inferencing part and logical inferencing part. The intuitive inferencing part offers the control strategy corresponding to the event which is most similar to the real event by searching based on a minimum distance classification method of pattern recognition methods. On the other hand, logical inferencing part makes real-time control strategy using real-time mode(best-first search method) when the intuitive inferencing is failed. Also, it builds up a knowledge base or appends a new knowledge to the knowledge base using pattern learning function. The expert system has main transformer fault, main transformer maintenance work and bus fault processing function. It is implemented as computer language, Visual C++ which has a dynamic programming function for implementing of inference engine and a MFC function for implementing of MMI. Finally, it's accuracy and effectiveness is proved by several event simulation works for a typical substation.