• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1170-1178
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• 2013

Thanks to various benefits, low-cost real-time communication networks so called fieldbus have been widely used in many industrial applications including military systems, such as aircrafts, submarines, and robots. This paper presents a reliability analysis of dual-channel CAN(Controller Area Network) fieldbus which is used for controlling various equipment of submarine combat system. A submarine combat system playing a critical role to the success of missions and survivability consists of various devices including sensors/actuators and computers. Since a communication network for submarine combat system must satisfy an extremely high level of reliability, a dual channel technique is commonly adopted. In this paper, a Petri Net based reliability model for dual-channel CAN is discussed. A reliability model called generalized stochastic Petri Nets (GSPN) is built by utilizing the information on physical faults with CAN. The effectiveness of the proposed model is analyzed in terms of unreliability with respect to failure rate and repair rate.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.74-80
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• 2006

This paper deals with the control and fault monitoring of a DDV hydraulic actuation system. A hydraulic servo system has a nonlinear dynamics of an orifice flow through a valve spool. A full nonlinear model for a DDV actuation system is driven, and linearized to a simple model which is convenient for a control loop and fault monitor design. A top level requirement on the performance and safety for the actuation system is introduced. A control system and fault monitoring structure which can meet these requirements are discussed. A simulation package for a DDV actuation system which has a triplex redundant structure is developed.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.436-446
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• 2023

In the field of safety-critical systems, analyzing the effects of various failure factors (failure modes) is essential through Failure Mode and Effects Analysis (FMEA). However, with the increasing importance of software in systems, applying FMEA analysis to the design phase has become challenging. This paper proposes the use of Automatic FMEA, which can automatically perform FMEA using model-based design techniques, and presents a case study of FMEA for automotive engines. A comparison is made between the model-based Automatic FMEA analysis tool and existing FMEA tools. The study aims to demonstrate the performance of the Automatic FMEA analysis tool and propose future research plans.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.5
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• pp.45-52
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• 2002

This paper presents fault detection scheme of Brushless DC(BLDC) motor drive system by estimating BLDC motor resistance using motor input and output data which is transmitted from data acquisition board to host computer over serial communication channel. Since communication time delay has a serious effect on performance, we use periodic and fixed communication protocol. Hence, the delay time is priory known. Simplified BLDC motor model and recursive least square algorithm is used for estimating motor resistance. By experiment result, we confirm the proposed scheme.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.270-272
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• 2008

철도전력설비에서 고장을 예측은 신뢰성기반 유지보수 및 신뢰성 및 안전성 분석에 가장 기본적인 요소 중의 하나이다. 본 논문에서는 전철전력설비 관련 국제 규격서를 검토하여 소개하였으며, 실제 철도전력시스템에서 발생하는 사고데이타를 분석하여 그에 따른 고장율과 고장데이타가 적을 경우 추정하여 철도 급전시스템에 적용할 수 있는 데이터베이스를 구축하고자 한다. 이러한 모델과 계산법의 목적은 시스템의 신뢰도 수준 결정, 시스템의 디자인 평가, 시스템 운영, 점검, 유지보수 프로그램 방침 평가 및 위험도 평가에 기여할 수 있다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.393_394
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• 2009

초전도한류기(SFCL)는 고장전류에 대한 초고속 감지, 고장전류 제한이 가능하고, 정상계통에서는 무손실 운영이 가능한 신개념의 기기이다. 공급신뢰도 측면에서 SFCL은, 고장전류 저감으로 송전을 지속할 수 있는 장점이 있는 반면, 기존 계통에 직렬연결되므로 자체 고장으로 인해 공급신뢰도를 악화시킬 수도 있다. 특히, 고속스위치를 필요로 하는 하이브리드형 SFCL의 경우 계통연계 이전에 SFCL 자체의 신뢰성이나 주위 계통에 미치는 영향을 미리 검토해야 한다. 본 논문에서는 SFCL의 신뢰도 데이터를 계산하는 기법과 SFCL 인근 설비의 신뢰도 데이터를 갱신하는 방법에 대해 제시하였으며, 이는 SFCL가 연계된 배전계통의 수용가 공급신뢰도를 산출하기 위해 필요한 사전단계에 해당한다.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.935-938
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• 1999

메모리 테스트는 Built-In Self Test(BIST)와 같이 메모리에 내장된 회로를 통하여 자체 점검하는 방법과 테스터를 통하여 생성된 패턴을 주입하는 방법이 있다. 테스트 패턴 생성방법으로는 각각의 고장모델에 대한 테스트 패턴을 deterministic하게 생성해주는 방법과 Pseudo Random Pattern Generator(PRPG)를 이용하여 생성하는 경우로 구분할 수 있다. 본 연구에서는 PRPG를 패턴 생성기로 사용하여 여러 가지 메모리의 결함을 대표한다고 볼 수 있는 Static 및 Dynamic Neighborhood Pattern Sensitive Fault(NPSF) 등 다양한 종류의 고장을 점검할 수 있도록 메모리 BIST를 구성하였다. 기존의 Linear Feedback Shift Register(LFSR)보다 본 연구에서 제안하는 Linear Hybrid Cellular Automata(LHCA)를 이용한 PRPG가 높고 안정된 고장 점검도를 나타내었다.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.84-86
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• 2001

본 연구에서는 플랜트의 계측신호로 부터 특징 패턴 파형들을 감지하고 패턴감지 정보로부터 플랜트의 운전상황 및 고장을 알아내도록 하는 새로운 기법을 제시하고, 이러한 기법의 실현에 필요한 신호처리 기초 연구를 수행하였다. 또한 보령화력 1.2호기 500MW급 드럼형 보일러및 제어 시스템을 대상으로 보일러 플랜트의 dynamics 모델링과 운전 시뮬레이션을 통하여 여러 운전 패턴및 고장 상황을 발생시켜 고장감지 앨고리즘들의 개발 및 시험과정에 적용하였다. 본 연구에서 수행한 보일러 및 보일러 제어계통에 대한 모델링 및 시뮬레이션은 실제 수행한 발전소 시험 데이터와 비교할 때 높은 일치도를 보이는 결과를 보였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.308-313
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• 2016

Modern systems have become more and more complex due to the ever-increasing user requirements and rapid advance of technology. As such, the frequency of accidents due to system design errors or failure has been increasing. When the damage incurred by accidents to human beings or property is serious, the underlying systems are referred to as safety-critical systems. The development of such systems requires special efforts to ensure the safety of the human beings operating them. To cope with such a requirement, in this paper an approach is employed in which we consider safety starting from the conceptual design phase of the systems. Specifically, a systems design method that can detect functional failure is proposed by utilizing meta-models and M&S methods. To accomplish this, the safety design data from international safety standards are first extracted and also a meta-model is generated using SysML (systems modeling language). Then, a SysML-based system design method is proposed based on the use of the developed meta-model. We also discuss how the safety requirements can be created and verified using a simulation method. Finally, through a case study in automotive design, it is demonstrated that the detection of a functional failure and the verification of a safety requirement can be accomplished using the SysML-based M&S method. This study indicates that the use of meta-models can be useful for collecting and managing safety data and that the meta-model based M&S method can make it possible to satisfy the system requirements by reducing the design errors.

• The Journal of the Acoustical Society of Korea
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• v.15 no.5
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• pp.73-81
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• 1996

In multiprocessor systems with multiple processors and memories, efficient communication between processors and memories is critical for high performance. Various types of multistage networks have been proposed. The economic feasibility and the improvements in both computing throughput and fault tolerance/diagnosis have been some of the most important factors in the development of these computer systems. In this paper, we present an efficient algorithm for the diagnosis of generalized cube interconnection networks with a fan-in/fan-out of 2. Also, using the assumed fault model present total fault diagnosis by generating suitable fault-detection and fault-location test sets for link stuck fault, switching element fault in direct/cross states, including broadcast diagnosis methods based on some basic properties or generalized cube interconnection networks. Finally, we illustrate some example.