• Title/Summary/Keyword: cut tree

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RECONSTRUCTION OF THE CUT TREE (CUT TREE의 재구축)

  • Kim, Chae-Bogk
    • Journal of Korean Institute of Industrial Engineers
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    • v.19 no.3
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    • pp.51-57
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    • 1993
  • This paper develops 0($n^3$) algorithm to construct a cut-tree generated by Gomory-Hu algorithm. The algorithm only requires node sets defined by the minimal cut in each of the (n-1) maximal flow determinations. Merging computerized facility layout procedure that uses cut-tree concept to generate design skeletons with our algorithm requires less storage space than merging it with Gomory-Hu algorithm. Also, the cut-tree can easily be modified when the (n-1) minimal cut-sets are updated due to changes on arc capacities.

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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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A Spanning Tree-based Representation and Its Application to the MAX CUT Problem (신장 트리 기반 표현과 MAX CUT 문제로의 응용)

  • Hyun, Soohwan;Kim, Yong-Hyuk;Seo, Kisung
    • Journal of Institute of Control, Robotics and Systems
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    • v.18 no.12
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    • pp.1096-1100
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    • 2012
  • Most of previous genetic algorithms for solving graph problems have used a vertex-based encoding. We proposed an edge encoding based new genetic algorithm using a spanning tree. Contrary to general edge-based encoding, a spanning tree-based encoding represents only feasible partitions. As a target problem, we adopted the MAX CUT problem, which is well known as a representative NP-hard problem, and examined the performance of the proposed genetic algorithm. The experiments on benchmark graphs are executed and compared with vertex-based encoding. Performance improvements of the spanning tree-based encoding on sparse graphs was observed.

A System Approach to A Bag Filter Failure using Fault Tree Analysis (Fault Tree Analysis을 활용한 집진기(Bag Filter) 고장의 체계적 분석)

  • 이근희;이동형
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.12 no.20
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    • pp.1-24
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    • 1989
  • This paper takes aim at the reliability evaluation by application of Fault Tree Analysis and its computerization. FTA is one of the methods for evaluation of system reliability and safety analysis. The important characteristic of this paper is that computer program is written in the package program(dBaseIII+) by 16Bit/AT personal computer. The program consists of three program segments. (1) The minimal cut sets of the system fault tree are obtained by means of "Fault tree reduction algorithm" (2) The minimal path sets are obtained by inversion of the minimal cut sets determined from fault tree (3) The importance of the basic events which are presented in the minimal cut sets is obtained by means of structural importance analysis. In this paper, a Fault Tree Analysis is applied to a BAG FILTER which is a kind of dust collector.collector.

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Fire Safety Analysis of Fire Suppression System for Aircraft Maintenance Hangar Using Fault Tree Method (Fault Tree를 활용한 항공기 격납고 소화시스템의 화재 안전성 분석)

  • Lee, Jong-Guk
    • Fire Science and Engineering
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    • v.31 no.6
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    • pp.67-73
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    • 2017
  • An aircraft maintenance hangar is a building that stores, maintains, and inspects expensive aircraft. The frequency of fire occurrence is low, but the resulting human and material damage can be very serious. Therefore, in this study, we conducted a qualitative analysis of the fire safety of the currently operating fire suppression systems for aircraft maintenance hangars using the Fault Tree method, and then performed a quantitative analysis using the failure rate data for the derived basic events and analyzed the importance of the minimal cut sets. As a result of the qualitative analysis by the minimal cut set, it was found that there were 14 accident paths that could be expanded to a large fire, due to the fire control failure of the aircraft hangar fire suppression system. The quantitative analysis revealed that, the probability of the fire expanding into a large one is $2.08{\times}E-05/day$. The analysis of the importance of the minimal cut set shows that four minimal cut sets, namely the fire detector and foam head action according to the zone and blocking of the foam by the aircraft wing and the fire plume, had the same likelihood of causing the fire to develop into a large one, viz. 24.95% each, which together forms the majority of the likelihood. It was confirmed for the first time by fault tree method that the fire suppression system of aircraft maintenance hangars is not suitable for fires under the aircraft wings and needs to be improved.

Cut tree approach for facility layout problem

  • Kim, Chae-Bogk
    • Korean Management Science Review
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    • v.11 no.3
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    • pp.55-65
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    • 1994
  • Given the flow matrix, plant size and department sizes, the algorithms in this paper provide the layout with rectilinear distance. To construct automated facility design, cut tree approach is employed. A branch and bound computer code developed by Tillinghast is modifided to find the feasible fits of departments without shape distortion in the plant rectangle.

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Minimal Cut Set of Electric Power Installations using Fault Tree Analysis (FTA를 이용한 수변전설비의 최소절단집합 도출)

  • Park, Young-Ho;Kim, Doo-Hyun;Kim, Sung-Chul
    • Journal of the Korean Society of Safety
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    • v.32 no.1
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    • pp.41-46
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    • 2017
  • In this paper, from making an electrical fire which is thought to be the most damaging among potential dangers as a top event, minimal cut sets (MCS) about it were analyzed. For this, components of a power substation were classified into 15 items. Failure rates and modes were extracted based on Korea Electrical Safety Corporation, IEEE Gold Book, and RAC. To analyze the top event (an electrical fire), main events were assorted into "safety devices for overcurrent" and "ampere meter of detecter". Failure of components was divided into failure of VCB, COS, and MCCB. A fault tree was composed of 3 AND gate, 5 OR gates and 17 basic events. Overlapped events among the basic events are things which occur from relevant components. They were attached to the tree by distinguishing identifiers. In case of FT, two minimal cut sets of "IO_METER", "MF_METER", "DO_MCCB" and "IO_METER", "MF_METER", "DO_VCB" take 46% of electrical fires. Therefore, about basic events which are included in the top two minimum cut sets, strict control is necessary.

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.

Multi-level Building Layout With Dimension Constraints On Departments (형태제약을 가지는 부서의 다층빌딩 설비배치)

  • Chae-Bogk Kim
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.26 no.4
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    • pp.42-49
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    • 2003
  • The branch and bound techniques based on cut tree and eigenvector have been Introduced in the literature [1, 2, 3, 6, 9, 12]. These techniques are used as a basis to allocate departments to floors and then to fit departments with unchangeable dimensions into floors. Grouping algorithms to allocate departments to each floor are developed and branch and bound forms the basis of optimizing using the criteria of rectilinear distance. The proposed branch and bound technique, in theory, will provide the optimal solution on two dimensional layout. If the runs are time and/or node limited, the proposed method is a strong heuristic The technique is made further practical by the fact that the solution is constrained such that the rectangular shape dimensions length and width are fixed and a perfect fit is generated if a fit is possible. Computational results obtained by cut tree-based algorithm and eigenvector-based algorithm are shown when the number of floors are two or three and there is an elevator.