• 한국정보처리학회논문지
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• 제5권12호
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• pp.3088-3098
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• 1998

순열 방사형 그래프는 병렬 또는 분산 시스템의 상호 연결망 구조로써 n-큐브의 새로운 대안으로 제시되고 있다. 그러나 최근까지 제시된 구조(메쉬, 하이퍼큐브 등)에 대한 오류 허용 설계 모델은 많이 연구되어왔지만 순열 방사형 그래프에 적합한 오류 허용 설계 모델은 연구되고 있지 않다. 따라서 본 논문에서는 순열 방사형 그래프에 적합한 새로운 오류 허용 설계방법을 제안하였다. 이 방법은 현재 수행중인 구성 요소 중에서 오류가 발생할 때 기존 구조를 유지하기 위해서, 예비 구성요소를 추가하여 적절히 오류 요소를 대치하는 기법이다. 먼저, 순열 방사형 그래프를 순환 그래프로 변환한 다음 순환 그래프의 준 동형 성질을 이용하였다. 또한 k개 예비프로세서를 추가하여 각 프로세서 당 최대 통신 링크를 최소화함으로써 오류 허용 설계구조의 비용을 최적화 하였다. 특히, 최대 통신 링크의 수를 최소화하는 새로운 연구 방법을 제안하였다.

• 품질경영학회지
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• 제21권1호
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• pp.78-95
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• 1993

The art of designing and analyzing fault-tolerant computers is surveyed with special emphasis on problems of analyzing the behavior of computers that have autonomous repair capability. The survey covers the following topics : (1) general issues in computer reliability, (2) fault-tolerance state relations and requirements, (3) computational hierarchy, (4) fault characteristics, (5) fault diagnosis, (6) fault-tolerance schemes for logic network and machines, (7) fault-coverage effects, and (8) fault-tree analysis of coverage. This paper does not include techniques for verifying nonredundant hardware or system software designs or for verifying the correctness of application programs.

• Journal of Power Electronics
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• 제10권1호
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• pp.34-42
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• 2010

Reliability is an important issue in cascaded H-bridge converters (CHB converters) because they use a high number of power semiconductors. A faulty power cell in a CHB converter can potentially lead to expensive downtime and great losses on the consumer side. With a fault-tolerant control strategy, operation can continue with the undamaged cells; thus increasing the reliability of the system. In this paper, the operating principles and the control method for a CHB multilevel rectifier are introduced. The influence of various faults on the CHB converter is investigated. The method of fault diagnosis and the bypassing of failed cells are explained. A fault-tolerant protection strategy is proposed to achieve redundancy in the CHB rectifier. The redundant H-bridge concept helps to deal with device failures and to increase system reliability. Simulation results verify the performance of the proposed strategy.

• 정보처리학회논문지C
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• 제8C권1호
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• pp.23-31
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• 2001

현재 CORBA는 분산환경에서 소프트웨어의 복잡성을 해결하기위한 방안으로 제시되어왔으나 데이터 전송에 대한 신뢰성 보장성이 부족하다. 특히 네트워크이 불안하거나 정체 되었을 때 이를 처리해주는 메카니즘이 없는 실정이다. 기존 CORBA에서는 클라이언트가 서버객체가 가지고 있는 객체를 서비스 받을 때, 네트워크상의 정체가 있는 경우 클라이언트는 무조건 기다려야 하는 단점이 있다. 이에 본 논문은 이러한 정체 시 요구된 서비스 객체들 다른 서버 객체가 지능적으로 우회 시켜주는 결함허용 서비스(Fault-Tolerant CORBA Service)를 제안한다. 이를 위해 본 논문은 신뢰성 지원을 위한 결함허용 서비스를 CORBA ORB에 확장하여 설계 및 구현하였다. 그러므로 제안된 결함허용 서비스를 통해 신뢰성 잇는 연결을 보장할 수 있다.

• 제어로봇시스템학회논문지
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• 제19권7호
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• pp.587-591
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• 2013

This paper addresses the robust fault tolerant controller design problems of static output systems with disturbance. The fault is expressed by the abrupt chattering of system parameters. The design conditions are derived in terms of linear matrix inequalities and linear matrix equalities. An illustrative example is provided to verify performances of the proposed controller.

• 자동차안전학회지
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• 제12권4호
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• pp.13-22
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• 2020

This paper presents an adaptive feedback based actuator fault detection and tolerant control algorithms for longitudinal functional safety of autonomous driving. In order to ensure the functional safety of autonomous vehicles, fault detection and tolerant control algorithms are needed for sensors and actuators used for autonomous driving. In this study, adaptive feedback control algorithm to compute the longitudinal acceleration for autonomous driving has been developed based on relationship function using states. The relationship function has been designed using feedback gains and error states for adaptation rule design. The coefficients in the relationship function have been estimated using recursive least square with multiple forgetting factors. The MIT rule has been adopted to design the adaptation rule for feedback gains online. The stability analysis has been conducted based on Lyapunov direct method. The longitudinal acceleration computed by adaptive control algorithm has been compared to the actual acceleration for fault detection of actuators used for longitudinal autonomous driving.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.239-243
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• 1993

In this paper, a fault-tolerant controller using duplex processors has been designed and implemented. The PI controller is adopted as the control algorithm and the fault-tolerant control system is implemented by two single chip processors(MCS-96). Performances of the control system designed here have been shown via a simulation with application to a pitch channel autopilot.

• 제어로봇시스템학회논문지
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• 제17권11호
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• pp.1154-1158
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• 2011

In this paper, we discuss an observer-based fault tolerant controller design for the T-S (Takagi-Sugeno) fuzzy system with exogenous disturbance. To derive robust controller design conditions, we use $H_{\infty}$ design technique. The design conditions are derived in terms of linear matrix inequalities. An illustrative example is provided to show the effectiveness of the proposed methodology.

• 제어로봇시스템학회논문지
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• 제18권5호
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• pp.407-412
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• 2012

In this paper, we discuss an observer-based fault tolerant controller design for the unmanned aerial vehicle (UAV) systems with exogenous disturbance. To derive robust controller design conditions, we use $H_{\infty}$ design technique. The design conditions are derived in terms of linear matrix inequalities. An illustrative example is provided to show the effectiveness of the proposed methodology.

• 정보학연구
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• 제9권4호
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• pp.25-34
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• 2006

As most application programs are more sophisticated and are adopted the distributed object technology, the object based distributed design became widespread since it supports portability and reusability. The approaches for fault-tolerant distributed computing are categorized into the active replica mechanism for mission-critical application programs and the passive replica mechanism for non mission-critical ones, when fault-tolerant facilities are added on. Our paper introduces the pros and drawbacks of several approaches for the add-on low-overhead fault-tolerant services by the surveys and shows the results of experiments for bench-mark models in order to demonstrate their performance.