• 제목/요약/키워드: Validity Check

검색결과 480건 처리시간 0.038초

화력 발전소 드럼형 보일러 시스템의 고장 진단을 위한 퍼지 전문가 시스템의 개발 (Development of Fuzzy Expert System for Fault Diagnosis in a Drum-type Boiler System of Fossil Power Plant)

  • 변승현;박세화
    • 전자공학회논문지B
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    • 제31B권10호
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    • pp.53-66
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    • 1994
  • In this paper, a fuzzy expert system is developed for fault diagnoisis of a drum-type boiler system in fossil power plants. The develped fuzzy espert system is composed of knowledge base, fuzzification module, knowledge base process module, knowledge base management module, inference module, and linguistic approximation module. The main objective of the fuzzy expert system is to check the states of the system including the drum level and detect faults such as the feedwater flow sensor fault, feedwater flow control valve fault, and water wall bube rupture. The fuzzy expert system diagnoses faults using process values, manipulated values, and knowledge base which is built via interviews and questionaries with the experts on the plant operations. Finally, the validity of the developed fuzzy expert system is shown via experiments using the digital simulator for boiler system is Seoul Power Plant Unit 4.

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FREE VIBRATION ANALYSIS OF PERFORATED PLATE WITH SQUARE PENETRATION PATTERN USING EQUIVALENT MATERIAL PROPERTIES

  • JHUNG, MYUNG JO;JEONG, KYEONG HOON
    • Nuclear Engineering and Technology
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    • 제47권4호
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    • pp.500-511
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    • 2015
  • In this study, the natural frequencies of the perforated square plate with a square penetration pattern are obtained as a function of ligament efficiency using the commercial finite-element analysis code ANSYS. In addition, they are used to extract the effective modulus of elasticity under an assumption of a constant Poisson's ratio. The effective modulus of elasticity of the fully perforated square plate is applied to the modal analysis of a partially perforated square plate using a homogeneous finite-element analysis model. The natural frequencies and the corresponding mode shapes of the homogeneous model are compared with the results of the detailed finite-element analysis model of the partially perforated square plate to check the validity of the effective modulus of elasticity. In addition, the theoretical method to calculate the natural frequencies of a partially perforated square plate with fixed edges is suggested according to the Rayleigh-Ritz method.

균일 분포하중을 받는 사다리꼴 주름판의 정적 해석 (Static Analysis of Trapezoidal Corrugated Plates under Uniformly Distributed Load)

  • 김영완
    • 동력기계공학회지
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    • 제18권1호
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    • pp.99-105
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    • 2014
  • In this paper, the static characteristics of the trapezoidal corrugated plate under uniformly distributed pressure are investigated by the analytical method. Because the corrugated plate is very flexible in the corrugation direction and stiff in the transverse direction, the corrugated plate is treated as the orthotropic plate. This equivalent orthotropic plate must include both the extensional and flexural effect to obtain the precise solution. The effective extensional and flexural stiffness of the trapezoidal corrugated plate are derived to consider these effects in the analysis. To demonstrate the validity of the proposed approach, the comparison is made with the previously published results. Some numerical results are presented to check the effect of the geometric properties.

저탄소사회 실현을 위한 농촌마을 계획지표 개발 (Development of Planning Indicators in Rural Village for Realization of Low Carbon Society)

  • 김은자;고아라;이정원;김상범
    • 농촌계획
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    • 제17권1호
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    • pp.29-42
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    • 2011
  • The Purpose of this study is to develop indicators for low carbon planning in rural village. We made two indicators for inland area and waterside area to consider regional disparities. To develop indicators, a draft of the indicators was estimated with collected research materials and 52 experts reviewed this draft three times with Modified Delphi Technique to check the validity and revise the draft. As a result, the inland indicators were settled with 4 domains 8 items 20 indicators and the waterside indicators were 4 domains 8 items 22 indicators. The final indicators will be used to realize low carbon rural village planning in future which the government is pushing forward with construction of six-hundred low carbon green village.

회전운동을 고려한 Cutout이 있는 복합재료 원통셸의 구조진동해석 및 최적설계 (Study on Structural Vibration Analysis and Design Optimization of Rotating Composite Cylindrical Shells with Cutout)

  • 이영신;김영완
    • 소음진동
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    • 제8권3호
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    • pp.467-476
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    • 1998
  • The free vibration analysis and design optimization of the rotating composite cylindrical shells with a rectangular cutout are investigated by theoretical method. The Love's thin shell theory is used to derive the frequency equation. The theoretical results are obtained by application of the energy method employing the Rayleigh-Ritz procedure. The used circumferential vibration modes are trigonometric functions, the axial modes are the beam modal functions chosen to satisfy the prescribed boundary conditions. To check the validity, the theoretical results are compared with experimental, FEM and other theoretical results.

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비선형 정규모드를 이용한 보의 비평면 자유진동해석 (Analysis of Nonplanar Free Vibrations of a Beam by Nonlinear Normal Mode)

  • 이원경;이규수;박철희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 춘계학술대회논문집
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    • pp.441-448
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    • 2000
  • An investigation into the nonlinear free vibrations of a cantilever beam which can have not only planar motion but also nonplanar motion is made. Using Galerkin's method based on the first mode in each motion, we transform the boundary and initial value problem into an initial value problem of two-degree-of-freedom system. The system turns out to have two normal modes. By Synge's stability concept we examine the stability of each mode. In order to check validity of the stability we obtain the numerical Poincare map of the motions neighboring on each mode.

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원통형 용기의 다단계 \ulcorner드로잉 공정설계에 관한 사례 연구 (A Case Study on the Process Planning for Multi-Stepped Deep Drawing of Complex Circular Shells)

  • 김두환
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1998년도 춘계학술대회논문집
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    • pp.160-167
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    • 1998
  • This article is aimed primarily at establishing a process planning method for complex circular shells. For the deep drawing of complex shaped shell, the optimum process design is required to reduce the trial cost, improve the quality, increase the productivity and shorten the delivery. The present approach which is related to the optimum process planning is based on the empirical knowledge through trial and error in the industrial field. In order to check the validity and the effectiveness of proposed work, a sample process design has been applied to the multi-stepped deep drawing of complex shell considering the process variables such as drawing rate, radius and blank development. In particular, the difference between the limiting drawing rate and the optimum drawing rate has been discussed and has been shown the usefulness of present suggestion.

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용착 금속을 고려한 필릿 용접에서 온도 분포 예측을 위한 해석적 모델 (An Analytical Solution for Transient Temperature Distribution in Fillet Arc Welding Including the Effect of Molten Metal)

  • 정선국;조형석
    • Journal of Welding and Joining
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    • 제13권3호
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    • pp.116-124
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    • 1995
  • This paper presents an analytical solution to predict the transient temperature distribution in fillet arc welding including the effect of molten metal. The solution is obtained by solving a transient three-dimensional heat conduction equation with convection boundary conditions on the surfaces of a plate, and mapping the infinite plate onto the fillet weld geometry with energy equation. The electric heat input on the fillet weld and on the infinite plate is assumed to have a combination of two bivariate Gaussian distribution. To check the validity of the solution. FCA welding experiments were performed under various welding conditions. The actual isotherms of the weldment cross-sections at various distances from the arc start point are compared with those of simulation result.

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KI Criteria of Surface Check under Stepwise Loadings of Drying Stresses

  • Park, Jung-Hwan
    • Journal of the Korean Wood Science and Technology
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    • 제27권4호
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    • pp.51-56
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    • 1999
  • Finite element method was utilized to analyze crack tip stress and displacement field under drying stress case as stepwise loading. Opening mode of single-edge-notched model was employed and analyzed by linear elastic fracture mechanics of plane stress case. The drying stresses were applied as stepwise loads at the boundary elements of the model with 10 steps of time serial. The stress intensity factor($K_I$) for opening mode reached to its maximum just prior to the stress reversal. The $K_I$ from the displacement fields revealed 1.7 times higher than those from stress fields. By comparing the two sets of $K_I$ from displacement and stress fields, single parameter $K_I$ showed its validity to characterize displacement fields around the crack tip front while stress field could not be characterized due to large variations between two sets of data.

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Discrete-Time Robust Guaranteed Cost Filtering for Convex Bounded Uncertain Systems With Time Delay

  • Kim, Jong-Hae
    • Transactions on Control, Automation and Systems Engineering
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    • 제4권4호
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    • pp.324-329
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    • 2002
  • In this paper, the guaranteed cost filtering design method for linear time delay systems with convex bounded uncertainties in discrete-time case is presented. The uncertain parameters are assumed to be unknown but belonging to known convex compact set of polytotype less conservative than norm bounded parameter uncertainty. The main purpose is to design a stable filter which minimizes the guaranteed cost. The sufficient condition for the existence of filter, the guaranteed cost filter design method, and the upper bound of the guaranteed cost are proposed. Since the proposed sufficient conditions are LMI(linear matrix inequality) forms in terms of all finding variables, all solutions can be obtained simultaneously by means of powerful convex programming tools with global convergence assured. Finally, a numerical example is given to check the validity of the proposed method.