• Proceedings of the Korean Society of Computer Information Conference
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• 2019.07a
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• pp.261-262
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• 2019

컨트롤러에 의해서 동작 및 운영되는 시스템들은 시스템의 내외부적인 요인으로 고장이 발생한 경우 정상적으로 작동할 수 없으며, 이 경우 2차 문제 발생 및 시스템 복구비용이 요구된다. 본 논문에서는 시스템 내부의 소프트웨어 오류 발생 시 컨트롤러 내의 감시 타이머를 사용하여 다운타임 시점 이전의 상태로 복구하는 알고리즘과, 하드웨어 오류의 경우 별도의 자동 리셋 기능을 통하여 시스템을 재설정하고 재 동작이 가능하도록 하는 기능을 구현한다. 제안 시스템은 시스템이 외부 지원 없이 자체적으로 반영구적인 동작이 가능하도록 함으로써, 시스템의 안정성과 신뢰성을 제공하고 운영 및 관리비용의 절감 효과를 제공한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.901-904
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• 2008

센서 네트워크를 이용하여 교량을 실시간으로 관리하기 위하여 미들웨어를 사용한다. 그러나 현재 미들웨어는 단순히 센서 네트워크에서 수집한 자료를 처리하는 단순한 수준에 불과하다. 본 논문에서 실시간으로 센서로부터의 정보를 수집/가공하고 센서 노드들과 전용 애플리케이션 및 웹 브라우저 간의 중재 역할을 하는 미들웨어를 제안한다. 또 데이터베이스 고장이 발생하였을 경우 파일로 수집정보를 저장 하며 데이터베이스가 복구되었을 때 데이터베이스 부하를 줄이기 위하여 데이터베이스의 사용률이 적을 때 파일로 수집된 정보를 데이터베이스에 저장하는 기능을 제안한다. 그리고 실시간으로 교량정보등을 감시하여 이상이 발생하였을 때 경고 메시지를 발생시켜 관리자가 교량의 비정상적인 상태에 대하여 빠르고 쉽게 인지할 수 있는 메커니즘을 제안한다.

• The Journal of Bigdata
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• v.7 no.1
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• pp.125-137
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• 2022

The transportation industry is one of the important industries due to the geographical requirements surrounded by the sea on three sides of Korea and the problem of resource poverty, which relies on imports for most of its resource consumption. Among them, the proportion of the shipping industry is large enough to account for most of the transportation industry, and maintenance in the shipping industry is also important in improving the operational efficiency and reducing costs of ships. However, currently, inspections are conducted every certain period of time for maintenance of ships, resulting in time and cost, and the cause is not properly identified. Therefore, in this study, the proposed methodology, LSTM-AutoEncoder, is used to detect abnormalities that may cause ship failure by considering the time of actual ship operation data. In addition, clustering is performed through clustering, and the potential causes of ship main engine failure are identified by grouping outlier by factor. This enables faster monitoring of various information on the ship and identifies the degree of abnormality. In addition, the current ship's fault monitoring system will be equipped with a concrete alarm point setting and a fault diagnosis system, and it will be able to help find the maintenance time.

• Journal of the Korea Society for Simulation
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• v.18 no.3
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• pp.103-112
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• 2009

In a nuclear power plant (NPP), periodic sensor calibrations are required to assure sensors are operating correctly. However, only a few faulty sensors are found to be calibrated. For the safe operation of an NPP and the reduction of unnecessary calibration, on-line calibration monitoring is needed. In this paper, principal component-based Auto-Associative support vector regression (PCSVR) was proposed for the sensor signal validation of the NPP. It utilizes the attractive merits of principal component analysis (PCA) for extracting predominant feature vectors and AASVR because it easily represents complicated processes that are difficult to model with analytical and mechanistic models. With the use of real plant startup data from the Kori Nuclear Power Plant Unit 3, SVR hyperparameters were optimized by the response surface methodology (RSM). Moreover the statistical techniques are integrated with PCSVR for the failure detection. The residuals between the estimated signals and the measured signals are tested by the Shewhart Control Chart, Exponentially Weighted Moving Average (EWMA), Cumulative Sum (CUSUM) and generalized likelihood ratio test (GLRT) to detect whether the sensors are failed or not. This study shows the GLRT can be a candidate for the detection of sensor drift.

• Journal of Advanced Navigation Technology
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• v.12 no.4
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• pp.295-303
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• 2008

Malfunction of satellite launch vehicles with high speed and long range can be a major concern for operations. Flight safety system that monitor the trajectory and identify any failure of the launch vehicles. Tracking filters for the flight safety systems are different from common tracking filters since filter reliability is more emphasized than accuracy. Reliable estimation of instantaneous impact points requires reliable velocity estimates as well as reliable position estimates. A fusion filter for a flight safety system was developed with the tracking sensor models for the Korea Satellite Launch Vehicle I. The fusion filter performances were evaluated by analyzing the trajectory and instantaneous impact point estimates.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.266-266
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• 2009

This paper describes important parameters used to evaluate the insulation performance of power supply components in metro substations. For online fault diagnosis of power supply components, we have developed a new remote condition monitoring system using wireless technology. Our developed system can continuously monitor electric power equipment such as transformers, circuit brakers, and rectifiers and have powerful wireless networking functions.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.2
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• pp.129-134
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• 2002

Operating the nuclear power generations safely is not easy way because nuclear power generations are very complicated systems. In the main control room of the nuclear power generations, about 4000 numbers of alarms and monitoring devices are equipped to handle the signals corresponding to operating equipments. Thus, operators have to deal with massive information and to analyze the situation immediately. If they could not achieve these task, then they should make big problem in the power generations. Owing to too many variables, operators could be also in the uncontrolled situation. So in this paper, the fault diagnosis system is designed using 2-steps neural networks. This diagnosis method is based on the pattern of the principal variables which could represent the type and severity of faults.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1333-1341
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• 2010

The goal of this research is to enhance the maintenance and monitoring system of ship environment using sensor network. It is important to know the location information of sensor nodes to control the sensors and to obtain the sensor data from sensor network inside the ship. In this paper, we address the grouping and routing mechanism according to the relative distance of sensor nodes, based on LEACH and PEGASIS. We also consider the fault tolerant mechanism using the location information of sensor nodes.

• Journal of the Korean Institute of Gas
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• v.2 no.3
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• pp.88-95
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• 1998

Vibration analysis of rotating machinery can give an indication of possible faults thus allowing maintenance before further damage occurs. Current predictive maintenance system installed in Pyung-tak has the ability to diagnose the mechanical problems within the LNG Pump when the vibration exceeds preset overall alarm levels. In this study, LNG pump auto-diagnosis system based upon Windows NT and DSP Board is developed. This system analysis velocity signal acquired from dual accelerometer input monitor system to diagnose pump condition. Many plots which display machine condition are shown and features of vibration are stored in every time. If the fault is found, the system diagnoses automatically using expert system and trend monitoring. Operator checks pump condition intuitively using personal computer monitor.

• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.535-541
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• 2009

The reliability of control system composed of electronic parts has been studied by DoD since 1960, and has been undertaken mainly by Europe for railways. Especially in Korea, a study on reliability of signalling equipment has been taken since 2000, requiring reliability test for effective maintenance of old type signalling equipment which no longer has information on its past reliability. This study evaluates the reliability test in units of parts for old type signalling equipment; for instance, failure rate in units of parts, or failure data during operation; which was utilized without its consistent reliability monitoring and analysis data for over 20 years. Also, reliability change at this point in time has been estimated by using residual life span function, and a model which can evaluate the possibility of extended operation through stress acceleration test has been developed. This model will be utilized to establish future maintenance policy for train operating company's operation on old type signalling equipment.