• Title/Summary/Keyword: fault tree

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An approximate approach for Computing Fault-tree probabilities (Fault-tree 확률계산을 위한 근사적 방법)

  • Lee, Geun-Hui;Lee, Dong-Hyeong
    • Journal of Korean Society for Quality Management
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    • v.18 no.2
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    • pp.25-32
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    • 1990
  • This paper presents an approximate algorithm for computing Fault-tree probabilities. The method is essentially composed of three steps. In the first step, a Fault-tree is converted into a network form. In the second step, We change the network into a parallelized diagram. In the third step, the approximate fault-tree probability is calculated from the parallelized diagram. In this paper, in order to verify the method two hypothetical Fault-tree is used by examples. The results show that the method is very useful, even though it is an approximate technique, since it needs not to search the minimal cut sets and has the simple computing rontines.

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Electrical Fire Hazards Analysis of Electric Iron and Heater Using Fault Tree Analysis

  • Hong, Sung-Ho
    • International Journal of Safety
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    • v.7 no.1
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    • pp.15-20
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    • 2008
  • The primary goal of this study is to analyze fire hazards of electric home appliances such as electric iron and electric heater using fault tree analysis(FTA). A fault tree(FT) is constructed and used to analyze fire hazards in electric home appliances. The fault tree is built from events that may occur in electric home appliances. The failure rate of basic events are derived from the value of experimental results and reference. And an algorithm analyzing fire in electric home appliances is suggested. We show how fault tree analysis, carried out by means of failure rate, is able to diagnose fire hazards of electric home appliances in a precise manner. We present numerical results such as fire probability of electric home appliances, importance measure, fire cause, etc. It can be helpful in preventing the fire hazards in electric home appliances.

A top-down iteration algorithm for Monte Carlo method for probability estimation of a fault tree with circular logic

  • Han, Sang Hoon
    • Nuclear Engineering and Technology
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    • v.50 no.6
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    • pp.854-859
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    • 2018
  • Calculating minimal cut sets is a typical quantification method used to evaluate the top event probability for a fault tree. If minimal cut sets cannot be calculated or if the accuracy of the quantification result is in doubt, the Monte Carlo method can provide an alternative for fault tree quantification. The Monte Carlo method for fault tree quantification tends to take a long time because it repeats the calculation for a large number of samples. Herein, proposal is made to improve the quantification algorithm of a fault tree with circular logic. We developed a top-down iteration algorithm that combines the characteristics of the top-down approach and the iteration approach, thereby reducing the computation time of the Monte Carlo method.

Fault Diagnosis of Screw type Air Compressor (스크루형 공기압축기의 고장진단)

  • Bae Yong-hwan
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.7
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    • pp.1092-1100
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    • 2004
  • This paper describes the application of fault tree technique to analyze of compressor failure. Fault tree analysis technique involves the decomposition of a system into the specific form of fault tree where certain basic events lead to a specified top event which signifies the total failure of the system. In this research. fault trees for failure analysis of screw type air compressor are made. This fault trees are used to obtain minimal cut sets from system failure and system failure rate for the top event occurrence can be calculated. It is Possible to estimate air compressor reliability by using constructed fault trees through compressor failure example. It is Proved that FTA is efficient to investigate the compressor failure modes and diagnose system.

Development of Alarm System Using Fault Tree Analysis for Pumping Station and Reservoir of Waterworks (Fault Tree 분석에 의한 상수도 가압장과 배수지의 경보시스템 구축)

  • Ahn, Yong-Po;Song, Moo-Geun;Lee, Dong-Ik
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.6
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    • pp.847-859
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    • 2011
  • This paper presents an alarm system for the integrated monitoring and control station of waterworks in Daegu City. An alarm system informs the operator or other responsible individuals about the abnormality in the process so that an appropriate action can be taken. In practice, operators receive far more false and nuisance alarms than valid and useful alarms. Too many false and nuisance alarms can distract the operator from operating the plant, and thus critical alarms may be ignored. This problem can lead to the point that the operator no longer trusts the alarms or even shuts down the whole monitoring system. This paper proposes an efficient method to reduce false and nuisance alarms by prioritizing every fault using the Fault Tree Analysis (FTA) technique. The effectiveness of the proposed method is evaluated with a set of computer simulation under various faulty conditions.

System Reliability Evaluation using Dynamic Fault Tree Analysis (동적 Fault Tree 분석을 이용한 시스템 신뢰도 평가)

  • Byun, Sungil;Lee, Dongik
    • IEMEK Journal of Embedded Systems and Applications
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    • v.8 no.5
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    • pp.243-248
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    • 2013
  • Reliability evaluation is important task in embedded system. It can avoid potential failures and manage the vulnerable components of embedded system effectively. Dynamic fault tree analysis is one of the reliability evaluation methods. It can represent dynamic characteristics of a system such as fault & error recovery, sequence-dependent failures. In this paper, the steering system, which is embedded system in vehicles, is represented using dynamic fault tree. We evaluate the steering system using approximation algorithm based on Simpson's rule. A set of simulation results shows that proposed method overcomes the low accuracy of classic approximation method without requiring no excessive calculation time of the Markov chain method.

Reliability Analysis Using Fault Tree (Fault Tree를 이용한 신뢰성 분석)

  • Lee, Chang-Hoon;Park, Soon-Dal
    • Journal of the military operations research society of Korea
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    • v.6 no.1
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    • pp.119-124
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    • 1980
  • An efficient algorithm which can be employed in obtaining the minimal cut sets of a fault tree containing repeated events is introduced. A sample fault tree illustrates this algorithm. Efficiency of an algorithm is defined as the ratio of the number of minimal cut sets to the number of cut sets determined by the algorithm. An efficiency of the proposed algorithm is compared with those of two existing algorithms : Fussell and Vesely's algorithm and Bengiamin et al. 's algorithm. The proposed algorithm is shown to be more efficient than the existing two algorithms.

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An Application of Fault Tree Analysis in Industrial Safety System (산업 안전시스템에 있어서 Fault Tree Analysis의 적용)

  • 김진규
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.13 no.21
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    • pp.43-50
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    • 1990
  • Fault tree analysis(FTA) is available to the engineer for determining reliability of complex industrial safety system. Therefore quantitative aspects of FTA greatly multiply its power this paper proceeds of presenting the methodology of FTA, including an approach to constructing in fault tree. A working guide to the use of FTA for the purpose of cost/benefit determination in industrial safety system is given. Finally, an analytic method for uncertainty analysis of the top event of a complex system is described.

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A Study on Reliability Evaluation Using Dynamic Fault Tree Algorithm (시스템 신뢰도 평가를 위한 동적 결함 트리(Dynamic Fault Tree) 알고리듬 연구)

  • 김진수;양성현;이기서
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.10A
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    • pp.1546-1554
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    • 1999
  • In this paper, Dynamic Fault Tree algorithm(DFT algorithm) is presented. This algorithm provides a concise representation of dynamic fault tolerance system including fault recovery techniques with fault detection, mask and switching function. And this algorithm define FDEP, CSP, SEQ, PAG gate which captures the dynamic characteristics of system. It show that this algorithm solved the constraints to satisfy the dynamic characteristics of system which there are in Markov and also this is able to satisfy the dynamic characteristics of system which there are in Markov and also this is able to covered the disadvantage of Fault tree methods. To show the key advantage of this algorithm, a traditional method, that is, Markov and Fault Tree, applies to TMR and Dual-Duplex systems with the dynamic characteristic and a presented method applies to those. He results proved that the DFT algorithm for solving the problems of the system is more effective than the Markov and Fault tree analysis model..

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Automatic Synthesis of Fault Tree Using Object-oriented Unit Modeling (객체지향 장치 모델링을 이용한 Fault Tree의 자동합성)

  • Hwang Kyu Suk;Hou Bo Kyeng
    • Journal of the Korean Institute of Gas
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    • v.5 no.2 s.14
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    • pp.1-8
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    • 2001
  • Fault tree construction for hazard assessment requires so much time and labor, so it is very difficult to be applied to the large scale chemical plant. In this study, for the synthesis of fault tree in chemical processes, the object-oriented knowledge framework is proposed to represent the deviations of process variables in the equipment and cause-consequence relationship with equipment faults. The cause of fault is searched by using the object-oriented modeling of equipments and the connectivity among equipments, and then a fault tree is synthesized. we have discussed the performance of the methodology on nitric acid cooling process to evaluate its effectiveness.

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