• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.170-170
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• 2003

• ICROS
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• v.18 no.4
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• pp.46-54
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• 2012

차량 간 통신 또는 차량과 인프라 간의 통신을 기반으로 자동차를 스마트화 또는 무인화 하려는 기술들이 지속적으로 개발되고 있다. 이러한 시스템의 안전성을 보장할 수 있는 신뢰도를 검증할 수 있는 방법들이 활발하게 개발되고 있다. 특히 제어기의 강인성과 고장감지의 신뢰도와 같은 관점에서 개발되는 알고리즘의 성능을 검증하는 방법에 대해서 살펴보고자 한다.

• Product Safety
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• s.200
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• pp.38-43
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• 2010

보통 주부들의 가사일 중 가장 큰 비중을 차지하는 일이 바로 빨래이다. 그만큼 세탁기는 주부들에게 많은 도움이 되고 있는 가전제품이다. 세탁기는 이러한 주부들의 욕구에 발맞춰 빠른 속도로 진화되고 있는데, 최근에는 다양한 세탁모션이 있고 센서가 감지해 세탁, 헹굼시간을 조절해주는 등 첨단 기능을 겸비한 드럼세탁기를 선호하는 추세다. 그럼 이제부터 드럼세탁기를 안전하게 고장 없이 오래오래 사용할 수 있는 방법을 알아보도록하자.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.27-29
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• 2015

현재 사용되고 있는 화재 통제 시스템은 화재 발생 시 단순한 열감지 센서를 통해 화재를 감지하고 연결된 경종에 신호를 보내 소리를 내어 알리는 방식을 사용하고 있다. 이러한 기계식 시스템은 잦은 고장과 낮은 정확도로 인한 신뢰도 문제뿐만 아니라 화재 발생 시 대피대상자들을 적절하게 유도하지 못하여 막대한 2차 피해가 발생하는 문제를 안고 있다. 본 논문에서는 IT 기술을 바탕으로 효율적이고 체계적으로 화제 통제를 지원하는 통합 시스템을 구현하였다. 이 시스템은 화재 통제의 핵심인 감지, 알림, 유도 기능의 효과를 극대화하도록 상호 연결되고 통합되어 있다.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.282-287
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• 2008

Identification of steady-state is the first step in developing a fault detection and diagnosis (FDD) system. In a complete FDD system, the steady-state detector will be included as a module in a self-learning algorithm which enables the working system's reference model to "tune" itself to its particular installation. In this study, a steady-state detector of a residential air conditioner based on moving windows was designed. Seven representing measurements were selected as key features for steady-state detection. The optimized moving window size and the feature thresholds was suggested through startup transient test and no-fault steady-state test. Performance of the steady-state detector was verified during indoor load change test. From the research, the general methodology to design a moving window steady-state detector was provided for vapor compression applications.

• Journal of Auto-vehicle Safety Association
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• v.11 no.2
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• pp.11-16
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• 2019

This paper suggests an algorithm for detecting fault of longitudinal controller in autonomous vehicles. Guaranteeing safety in fault situation is essential because electronic devices in vehicle are dependent each other. Several methods like alarm to driver, ceding control to driver, and emergency stop are considered to cope with fault. This research investigates the fault monitoring process in fail-safe system, for controller which is responsible for accelerating and decelerating control in vehicle. Residual is computed using desired acceleration control command and actual acceleration, and detection of its abnormal increase leads to the decision that system has fault. Before computing residual for controller, health monitoring process of acceleration signal is performed using hardware and analytic redundancy. In fault monitoring process for controller, a process model which is fitted using driving data is considered to improve the performance. This algorithm is simulated via MATLAB tool to verify performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.52-60
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• 2003

In aviation navigation using GPS, requirements on availability and integrity must be absolutely satisfied. Current study on accomplishing this integrity includes RAIM(Receiver Autonomous Integrity Monitoring), monitoring integrity internaIly in GPS receiver itself. Parity space technique as one of RAIM techniques has shown the advantages in fault detection and isolation due to each use of its magnitude and direction under the assumption of one fault. ln case of multiple fault, as biases in errors interact decreasing the effect of multiple fault in parity space, the exact fault detection and identification(FDI) may be difficult to be conducted. This paper focuses on FDI study on two faults and explains why parity space techniques applied on single fault is not adequate to the application of multiple fault case and shows that extended parity space technique may improve the performance of RAIM on two faults.

• Journal of Navigation and Port Research
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• v.46 no.3
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• pp.280-288
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• 2022

This study examined the diagnostics of abnormalities and faults of equipment, whose rotational speed changes even during regular operation. The purpose of this study was to suggest a procedure that can properly apply machine learning to the time series data, comprising non-stationary characteristics as the rotational speed changes. Anomaly and fault diagnosis was performed using machine learning: k-Nearest Neighbor (k-NN), Support Vector Machine (SVM), and Random Forest. To compare the diagnostic accuracy, an autoencoder was used for anomaly detection and a convolution based Conv1D was additionally used for fault diagnosis. Feature vectors comprising statistical and frequency attributes were extracted, and normalization & dimensional reduction were applied to the extracted feature vectors. Changes in the diagnostic accuracy of machine learning according to feature selection, normalization, and dimensional reduction are explained. The hyperparameter optimization process and the layered structure are also described for each algorithm. Finally, results show that machine learning can accurately diagnose the failure of a variable-rotation machine under the appropriate feature treatment, although the convolution algorithms have been widely applied to the considered problem.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1104-1114
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• 2000

If the control system that works important job fails, economical loss occurred. Hence, to guarantee high reliability, it must be duplicated. In the case of traditional duplication mechanism, dedicated operating system with duplication functions were built. This required much development and maintenance cost. They can be saved, if we use commercial operating system and its development environment.This paper proposes a duplication mechanism for the system based on commercial 0S. The system that explained in this paper is BSC(Base Station Controller). The duplicated BSC system uses concurrent write memory for synchronization and VxWorks as an operating system. We propose how the task supporting duplication functions is executed without delay and preemption, how to synchronize standby's memory with active' s, and how to use concurrent-write memory easily with VxWorks' s partition. We also describe the takeover procedure when the active detects its hardware fault and when the standby recognizes the failure of the active.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.721-724
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• 2016

Because of the inherent uncertainties caused by the manufacturing process variations, future loading conditions, and incomplete damage models, the lifetimes of mechanical structures under field conditions are significantly different from the results obtained in the laboratories. In this study, a dual sensor was developed to prognosticate the fatigue failure of structures under these uncertain conditions, and its effectiveness was demonstrated on a rectangular columnar structure under repeated uni-axial loading. The dual sensor is a slightly weaker structure embedded in the target structure, so that failure occurs in the sensor earlier than in the target structure. From the signal differences in the strain gauges in the embedded dual sensor, it is possible to differentiate between the normal status and warning status, even under variable loads.