• Title, Summary, Keyword: Fault analysis

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Fault Analysis, Using Two-Port Network (4 단자망을 이용한 고장해석)

  • Kim, Jo-Yong;Baek, Young-Sik
    • Proceedings of the KIEE Conference
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    • pp.124-127
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    • 1993
  • This paper presents the new algorithm for fault analysis and the fault analysis package for executing this algorithm. This algorithm obtains requisite term for fault analysis by the two-port network technique. Therefore, the fault calculation time is minimized because ${Y_{BUS}}^{-1}$ calculation time is removed. And, the graphic user environment for fault analysis is implemented in mouse-oriented user interface with window and pull-down menu. Therefore, this package can be a useful tool for fault analysis.

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Fault Tree Analysis based on State-Transition Model (상태 전이 모델 기반 결함 트리 분석)

  • Chung, In-Sang
    • The Journal of the Korea Contents Association
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    • v.11 no.10
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    • pp.49-58
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    • 2011
  • Fault Tree Analysis(FTA) builds fault trees to perform safety analysis of systems. However, building fault trees depends on domain knowledge and expertize on target systems and consumes lots of time and efforts. In this paper, we propose a technique that builds fault trees systematically based on state-transition models which are software design artifacts. For the end, this paper identifies conditions that should be satisfied to guarantee safety of state-transition models and develop templates for fault tree construction. This paper also describes the results of appling the proposed method to railway crossing control system.

Development of Automatic Fault Tree Construction System using Digraph (Digraph를 이용한 Fault Tree 자동합성시스템의 개발)

  • Jung, Won-Seok;Lee, Geun-Won;Moon, Il
    • 제어로봇시스템학회:학술대회논문집
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    • pp.393-393
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    • 2000
  • FTA(Fault Tree Analysis) is a safety analysis method that focuses on one particular accident or main system failure and provides a method of determining causes of that event. While most of the statistical and cut set analysis have been automated, actual construction of the fault-tree is usually done manually. Manual construction of the fault-tree is extremely time consuming and it requires high level of expertise and experience. In addition to the time involved, different analyst often produces different fault-trees either by incorrect logic or omission of certain events. Automatic fault-tree construction system can be efficient in solving above problems. This study presents a new Digraph-FT conversion algorithm that leads automatic FTA system.

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Design and implementation of simulator for fault coverage analysis of commuication protocol test case (통신 프로토콜 시험항목의 오류 발견 능력 분석을 위한 시뮬레이터의 설계 및 구현)

  • 김광현;허기택;이동호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.8
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    • pp.1823-1832
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    • 1997
  • In this ppaer, fault coverage analysis of a conformance test case for communication protocols, specified as a deterministic finite state machine(DFSM) is presented. The fault coverage analysis of a test case is defined by measuring the extent of the faults detected using a generated test case. The method that evaluates fault coverage analysis for a test case, has been researched by arithmetic analysis and simulation. In this paper, we designed and implemented a simulator for fault coverage analysis of a communication protocol teat case. With this result for Inres protocol, output fault and state merge and split fault have a high fault coverage of 100%. This simulator can be widely used with new fault coverage analysis tools by applying it to various protocols.

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Canonical correlation analysis based fault diagnosis method for structural monitoring sensor networks

  • Huang, Hai-Bin;Yi, Ting-Hua;Li, Hong-Nan
    • Smart Structures and Systems
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    • v.17 no.6
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    • pp.1031-1053
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    • 2016
  • The health conditions of in-service civil infrastructures can be evaluated by employing structural health monitoring technology. A reliable health evaluation result depends heavily on the quality of the data collected from the structural monitoring sensor network. Hence, the problem of sensor fault diagnosis has gained considerable attention in recent years. In this paper, an innovative sensor fault diagnosis method that focuses on fault detection and isolation stages has been proposed. The dynamic or auto-regressive characteristic is firstly utilized to build a multivariable statistical model that measures the correlations of the currently collected structural responses and the future possible ones in combination with the canonical correlation analysis. Two different fault detection statistics are then defined based on the above multivariable statistical model for deciding whether a fault or failure occurred in the sensor network. After that, two corresponding fault isolation indices are deduced through the contribution analysis methodology to identify the faulty sensor. Case studies, using a benchmark structure developed for bridge health monitoring, are considered in the research and demonstrate the superiority of the new proposed sensor fault diagnosis method over the traditional principal component analysis-based and the dynamic principal component analysis-based methods.

Fault Tree Construction Method using Function Deployments of Machine Parts (기능 전개를 활용한 기계류 부품의 Fault Tree 구성에 관한 연구)

  • 하성도;이언경;강달모
    • Proceedings of the Korean Reliability Society Conference
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    • pp.257-263
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    • 2001
  • In the analysis of product reliability, the fault tree is widely used since it shows the interrelations of the faults that lead to the product fault. A top-down approach based on experts’ experience is commonly used in the fault tree construction and the trees often take different forms depending on the intent of the analyst. In this work it is studied how to construct fault trees with the utilization of function trees obtained from analyzing the functions and sub-functions of products in order to suggest a generic way of fault tree construction. The function tree of a product is obtained by analyzing basic functions comprising the product main function in a bottom-up approach so that it enables to construct an objective fault tree. The fault tree for a scroll compressor is shown as an example.

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A study on the Design Techniques and Analysis of Fault-Tolerant Computers

  • Cho, Jai-Rip
    • Journal of the Korean Society for Quality Management
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    • v.21 no.1
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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.

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Evaluation of effectiveness of fault-tolerant techniques in a digital instrumentation and control system with a fault injection experiment

  • Kim, Man Cheol;Seo, Jeongil;Jung, Wondea;Choi, Jong Gyun;Kang, Hyun Gook;Lee, Seung Jun
    • Nuclear Engineering and Technology
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    • v.51 no.3
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    • pp.692-701
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    • 2019
  • Recently, instrumentation and control (I&C) systems in nuclear power plants have undergone digitalization. Owing to the unique characteristics of digital I&C systems, the reliability analysis of digital systems has become an important element of probabilistic safety assessment (PSA). In a reliability analysis of digital systems, fault-tolerant techniques and their effectiveness must be considered. A fault injection experiment was performed on a safety-critical digital I&C system developed for nuclear power plants to evaluate the effectiveness of fault-tolerant techniques implemented in the target system. A software-implemented fault injection in which faults were injected into the memory area was used based on the assumption that all faults in the target system will be reflected in the faults in the memory. To reduce the number of required fault injection experiments, the memory assigned to the target software was analyzed. In addition, to observe the effect of the fault detection coverage of fault-tolerant techniques, a PSA model was developed. The analysis of the experimental result also can be used to identify weak points of fault-tolerant techniques for capability improvement of fault-tolerant techniques

3D Finite Element Analysis of Fault Displacements in the Nobi Fault Zone, Japan

  • Choi, Young-Mook;Kim, Woo-Seok;Lee, Chul-Goo;Kim, Chang-Yong;Seo, Yong-Seok
    • The Journal of Engineering Geology
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    • v.24 no.3
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    • pp.323-332
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    • 2014
  • The Nobi fault zone, which generated the 1891 Nobi Earthquake (M8.0), includes five or six faults distributed in and around Gifu and Aichi prefectures, Japan. Because large cities are located near the fault zone (e.g., Gifu and Nagoya), and because the zone will likely be reactivated in the future, relatively thorough surveys have been conducted on the 1891 Nobi earthquake event, examining the fault geometry, house collapse rate, and the magnitude and distribution of earthquake intensity and fault displacement. In this study, we calculated the earthquake slip along faults in the Nobi fault zone by applying a 3D numerical analysis. The analysis shows that a zone with slip displacements of up to 100 mm included all areas with house collapse rates of 100%. In addition, the maximum vertical displacement was approximately ${\pm}1700mm$, which is in agreement with the ${\pm}1400mm$ or greater vertical displacements obtained in previous studies. The analysis yielded a fault zone with slip displacements of > 30 mm that is coincident with areas in which house collapse rates were 60% of more. The analysis shows that the regional slip sense was coincident with areas of uplift and subsidence caused by the Nobi earthquake.

A New Study on Vibration Data Acquisition and Intelligent Fault Diagnostic System for Aero-engine

  • Ding, Yongshan;Jiang, Dongxiang
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.16-21
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    • 2008
  • Aero-engine, as one kind of rotating machinery with complex structure and high rotating speed, has complicated vibration faults. Therefore, condition monitoring and fault diagnosis system is very important for airplane security. In this paper, a vibration data acquisition and intelligent fault diagnosis system is introduced. First, the vibration data acquisition part is described in detail. This part consists of hardware acquisition modules and software analysis modules which can realize real-time data acquisition and analysis, off-line data analysis, trend analysis, fault simulation and graphical result display. The acquisition vibration data are prepared for the following intelligent fault diagnosis. Secondly, two advanced artificial intelligent(AI) methods, mapping-based and rule-based, are discussed. One is artificial neural network(ANN) which is an ideal tool for aero-engine fault diagnosis and has strong ability to learn complex nonlinear functions. The other is data mining, another AI method, has advantages of discovering knowledge from massive data and automatically extracting diagnostic rules. Thirdly, lots of historical data are used for training the ANN and extracting rules by data mining. Then, real-time data are input into the trained ANN for mapping-based fault diagnosis. At the same time, extracted rules are revised by expert experience and used for rule-based fault diagnosis. From the results of the experiments, the conclusion is obvious that both the two AI methods are effective on aero-engine vibration fault diagnosis, while each of them has its individual quality. The whole system can be developed in local vibration monitoring and real-time fault diagnosis for aero-engine.

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