• Title, Summary, Keyword: 링해석법

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Beat Control Method Using the Finite Element Analysis of an Equivalent Ring (등가 링의 유한요소해석을 이용한 맥놀이 조절법)

  • Kim, Seock-Hyun;Cui, Cheng-Xun
    • The Journal of the Acoustical Society of Korea
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    • v.27 no.7
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    • pp.365-371
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    • 2008
  • In this study, beat control method using an equivalent ring model is proposed to control beat period of a slightly asymmetric ring. Slight asymmetry in a ring generates mode pair and the interaction of the mode pair makes beat in vibration and sound. In a ring, as a simplified bell type structure, mode data are measured and an equivalent ring is determined so that the measured mode condition is satisfied. By the finite element analysis on the equivalent ring, changes of mode pair condition are predicted when local mass is attached or the local thickness is decreased. The predicted results are compared with the experimental result and the validity of the proposed method is verified.

A Study on the Optimized Design of O-rings for LPG Filling Unit (LPG 충전노즐에 장착된 O-링의 최적설계에 관한 연구)

  • Kim Chung-Kyun;Kim Do-Hyun
    • Journal of the Korean Institute of Gas
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    • v.10 no.3
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    • pp.34-40
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    • 2006
  • This paper presents the optimized design of O-rings with a rectangular groove and dovetails, which are strongly related on the sealing performance of LPG filling unit. The computed results on the optimal design are analyzed by non-linear MARC finite element program with Taguchi method. O-rings with 4 different groove models are analyzed for 3 different elastomeric materials. The design parameters are given to polymer materials, groove depth, groove width, and diameter of O-rings. The FEM computed results showed that the affection ratios of O-ring diameter and material property are the most influential parameter among the groove width, groove depth, and compression ratio. Thus, this paper recommends model III for a rectangular groove and model IV for a dovetail groove with a given gas supply pressure of 1.764 MPa.

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Safety evaluation for oven structures using parametric method (설계 변수법을 이용한 밥솥 체결 구조물의 안전도 평가)

  • Lee, Seung-Pyo;Koh, Byung-Kab;Ha, Sung-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.4
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    • pp.853-858
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    • 2008
  • The structures of induction heating type pressure rice cooker are consisted of oven. top heater plate and locking ring. Because the pressure is applied to their structures, those should be necessary to do the safety evaluation. In this paper, structure analysis is performed for oven structures by using finite element method and as a results, optimal thickness is achieved. Especially, analysis fur anisotropic layered material is performed because oven is made of both stainless steel and aluminum. And both von Mises and Tsai-Wu failure criterion are applied for safety factor. Parametric method is used in order to get the optimal thickness for oven and top heater plate.

Prediction of the Dynamic Derivatives of Separated Payload Fairing Halves by the CFD Analysis of Forced Harmonic Motions (강제조화운동 전산유동해석을 통한 분리된 페어링 동안정 미계수 예측)

  • Kim, Yeong-Hun;Ok, Ho-Nam;Kim, In-Seon
    • Aerospace Engineering and Technology
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    • v.5 no.2
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    • pp.149-158
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    • 2006
  • A review has been made on what kind of method can be applied to predict the dynamic derivatives of the separated PLF(Payload Fairing) halves of a launch vehicle in consideration of technology and budget. An optimal approach is selected considering the geometric characteristics of the PLF halves, the aerodynamic conditions and the required accuracy. The time history of aerodynamic force/moment coefficients are obtained for the forced harmonic motions by solving the unsteady Euler equations derived with respect to the inertial reference frame. and the dynamic derivatives are deduced by integration of the aerodynamic coefficients for one period. In this research, the dynamic derivatives are presented for 0.6$\leq$ M $\leq$2.0, $-180^{\circ}$ $\leq$$\alpha$ $\leq$$180^{\circ}$ and $-90 ^{\circ}$$\leq$$\beta$$\leq$$90 ^{\circ}$.

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Development of Continuous Spoken Digit Recognition System using Statistical Model (통계적 모델에 의한 연속 숫자음의 인식 기술개발)

  • Lee, G.S.;Ann, T.O.;Kim, S.H.
    • Annual Conference on Human and Language Technology
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    • pp.154-158
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    • 1989
  • 본 연구는 통제적 모델에 의한 연속 숫자음의 인식에 관한 것으로 4 연속 숫자음을 인식 대상으로하여 실험한다. 시스템은 크게 음향 음성 처리부 및 어휘 해석부 두 부분으로 나뉜다. 음향 음성 처리부에서는 입력 음성으로부터 특정 벡터인 12차의 LPC cepstrum 계수를 구하여, 프레임 레이블링과 소음소 레이블링 (phone labelling)을 한다. 프레임 레이블링인 베이스 분류법을 이용하였으며, 소음소 레이블링은 프레임 레이블과 사후확률 (posteriori probability)로 부터 이루어 졌다. 어휘 해석부분에서는 소음소 단위를 입력으로 받아 음운규칙을 통해 작성된 소음소 망을 거쳐 연속 숫자음 출력을 얻도록 했다. 본실험은 화자 3 명이 발음한 35 개의 4 연속 숫자음을 인식 대상으로 하였으며, 4 연속 숫자음을 평가단위로 80%의 인식율을 얻었고, 각 숫자음의 음절을 단위로 95%의 인식율을 얻어 제시한 알고리즘의 유효성을 입증하였다.

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An Analysis of High Speed Forming Using the Explicit Time Integration Finite Element Method (I) -Effects of Friction and Inertia Force- (엑스플리시트 시간 적분 유한요소법을 이용한 고속 성형 해석 (I) -마찰 및 관성 효과-)

  • 유요한;정동택
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.1-10
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    • 1991
  • Two-dimensional explicit finite element code was developed. The transient dynamics code can analyse large deformations of non-linear materials subjected to extremely high strain rates. The Lagrangian finite element program uses an explicit time integration operator to integrate the equations of motion, thus the stiffness matrix is not introduced. Cylinder upsetting and ring compression problems are simulated to check the effects of friction and inertia force. It is shown that (1) calculated results agree very well with experimental results, (2) constant shear friction method overestimates the decrease of inner ring radius and then underestimates after on in comparison with the Coulomb friction method, and (3) the effect of the increase in initial strain rate is similar to the effect of higher frictional coefficient.

Free Vibration Analysis of Thick Circular Ring from Three-Dimensional Analysis (두꺼운 원형링의 3차원적 자유진동해석)

  • 양근혁;강재훈;채영호
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.4
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    • pp.609-617
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    • 2002
  • A three-dimensional(3-D) method of analysis is presented for determining the free vibration frequencies and mode shapes of thick, circular rings with isosceles trapezoidal and triangular cross-sections. Displacement components u/sub s/, u/sub z/, and u/sub θin the meridional, normal, and circumferential directions, respectively, are taken to be sinusoidal in time, periodic in θ, and algebraic polynomials in the ψ and z directions. Potential(strain) and kinetic energies of the circular ring are formulated, and upper bound values of the frequencies we obtained by minimizing the frequencies. As the degree of the polynomials is increased, frequencies converge to the exact values. Novel numerical results are presented for the circular rings with isosceles trapezoidal and equilateral triangular cross-sections having completely free boundaries. Convergence to four-digit exactitude is demonstrated for the first five frequencies of the rings. The method is applicable to thin rings, as well as thick and very thick ones.

Analysis of Rectangular Ring Microstrip Antenna (사각 링 마이크로스트립 안테나 해석)

  • 서동국;박병우
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.1
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    • pp.60-67
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    • 2004
  • In this paper, a rectangular ring microstrip patch antenna has been analyzed by using desegmentation method and evaluation impedance matrices from Green's functions fur rectangular segment and desegmentation method for analysis of planar electro-magnetic structures is discussed. As the rectangular ring cavity could be seen as a structure subtracted a small rectangular cavity from a large one, the overall impedance matrix was obtained by applying a multiport connection method to the individual impedance matrices expressed as a term of Green's function fer rectangular segment. The electromagnetic fields can be solved from a vector potential which is satisfied it's eight boundary conditions. The electric field distribution at each edges was expressed as a histogram table with exciting modes. These results can be used to analyze the operational modes for a rectangular ring microstrip antennas.

Critical Speed Analysis of the Liquid Rocket Turbopump (액체로켓 터보펌프의 임계 속도 해석)

  • Jeon, Seong-Min;Kwak, Hyun-Duck;Yoon, Suk-Hwan;Kim, Jin-Han
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.6
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    • pp.92-99
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    • 2005
  • Numerical analyses of critical speed and mass unbalance response are performed for a 30 ton thrust turbopump. The stiffness and damping of ball bearings and non-contact seals are quantified under aerodynamic and hydrodynamic loads induced by a fuel pump and turbine. Critical speed margin and tip displacements of the rotating parts are evaluated using a three-dimensional finite element method. The results are used to ensure the soundness of the rotordynamic design using an one-dimensional transfer matrix method. A further study shows that sufficient resonance margin may be assured via controlling the stiffness of the rotor support by employing an additional elastic ring to the bearing support.

Data analysis for quantitative proteomics research (프로테오믹스 연구를 위한 정량분석 데이터의 해석)

  • Kwon Kyung-Hoon
    • KOGO NEWS
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    • v.6 no.1
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    • pp.24-28
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    • 2006
  • 프로테오믹스는 생물체 안에 포함되어 있는 단백질을 통합적으로 연구한다. 단백질을 동정(Protein identification)하고, 단백질의 상태를 분석(Protein characterization)하며, 단백질의 양적 변화를 관찰(Protein quantitation)한다. 단백질에 대한 분석, 특히 질량분석기에 의해 초고속으로 대량의 단백질 데이터를 생산하는 프테테오믹스의 연구는 정량적인 단백질 발현양상분석의 정확도를 높이고 분석시간을 단축하기 위해 다양한 실험기법과 데이터 분석기법을 동원하고 있다. 1) 단백질의 양적 차이나 양적 변화의 관찰은 바이오마커를 발굴하고 생명현상의 메카니즘을 규명하여 그 결과를 신약개발에 활용하기 위한 기초 연구이다. 이 글에서는 프로테오믹스 연구의 초창기부터 사용되어온 2차원 전기영동법에 의해 생성되는 2D-gel image에서의 스팟(spot)분석법과 함께, 탄뎀 질량분석기를 사용하는 ICAT, SILAC 등의 동위 원소를 사용한 라벨링(labeling) 방법, 라벨링을 하지 않는 label-free 방법 등 프로테오믹스에서의 정량분석법에 대한 기본 개념을 살펴보고, 이들에서의 데이터 분석 기술의 적용에 대해 간략히 소개하였다.

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