• 제목/요약/키워드: Displacement function

검색결과 1,012건 처리시간 0.032초

PSP 압력측정을 위한 상관법에 의한 이미지 등록 (Correlation-Based Image Registration for Pressure Measurements Using Pressure-Sensitive Paint)

  • 박상현;성형진
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.1778-1782
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    • 2004
  • A new algorithm, CBIR (Correlation-Based Image Registration) was proposed to improve the resolution of image registration for PSP (Pressure-Sensitive Paint). The local displacement vectors were obtained by finding the displacement which maximizes the cross-correlation between two interrogation windows of 'wind-off' and 'wind-on' images. A recursive multigrid processing was employed to increase the non-linear spatial resolutions. The variations of image were precisely measured without identifying the control points.

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환기에 의한 실내 부유오염입자 제거특성에 관한 실험적 연구 (Experimental Study on Removal Characteristics of Indoor Suspended Particulates by Ventilation.)

  • 강태욱
    • 한국태양에너지학회 논문집
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    • 제25권4호
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    • pp.133-139
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    • 2005
  • In this paper, the ventilation performance of suspended particulates in indoor side was investigated by step-down method. Experiments were performed in function of mechanical ventilation types and locations of supply and extract air. The type 2 ventilation system shows the highest removal characteristics rather than other 2 types. It means that the displacement ventilation has also good decay rates of concentration compared to mixing ventilation.

양측식 선형펄스모터의 자기회로 및 정추력해석 (Analysis of Magnetic Circuit and Static Thrust of a Double-sided Linear Pulse Motor)

  • 박한석;노창주
    • Journal of Advanced Marine Engineering and Technology
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    • 제20권1호
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    • pp.49-55
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    • 1996
  • In this paper, the characteristics of a double-sided linear pulse motor (DLPM) with permanent magnet are analysed using the method which combined the coenergy method and the equivalent magnetic circuit method. In the process of computation, the magnetic material nonlinealities of the permanent magnet, the primary and the secondary core are interpolated by the cubic spline method. Then, the equivalent magnetic circuit modelled by the permeance method including airgap reluctance, which is a function of displacement, is obtained. The static thrust which is the derivative of coenergy is computed by Newton Raphson method at each dispacement. And, in order to investigate the characteristics of the DLPM, the thrust shows as a function of displacement, input current and air gap. The simulation resuls are compared with experimental ones obtained from the DLPM with 2 phase and 4 poles.

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인덕턴스 특성을 이용한 자기부상계의 변위 측정의 한 방법에 관한 연구 (A Study on a Displacement Measurement Method of Magnetic Levitation System Applying the Inductance Characteristic)

  • 김창화;양주호
    • 소음진동
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    • 제6권3호
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    • pp.357-362
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    • 1996
  • The magnetic levitation system has great advantages, such as little friction, no lubrication, no noise and so on. But the magnetic levitation system need a stabilizing controller because it is a unstable, system in natural and it need a sensor for displacement measurement to control the system. In this paper, we proposed a sensorless method to measure the gap between the magnetic pole and the levitated object with application the inductance characteristic which vary according to gap. We made a driving circuit which supply simultaneously the control input PWM(Pulse Width Modulation) signal and the carrier PWM signal to estimate the gap. Because the inductance is a function of gap, and the current of the carrier signal is a function of the inductance, we could estimate the gap from the measurement of the current of the carrier signal. Finally, we investigated the validity of the proposed method through the experimental results.

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자동차용 스프링 성형용 CAM의 성형설계자동화 프로그램 개발 (A study on programming Development Forming Design Automated of CAM for Spring using Car)

  • 박철우;이주현;김영호
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.1353-1357
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    • 2005
  • A CAM program for forming design Automated of CAM for Spring using car was developed in this study. This program was written in AUTO-LISP on the AUTO-CAD system with a personal. An approach to the system is based on the kinemateic of the object function. We make a determination of an cam programming. A cam spline is continuous in displacement, velocity and acceleration. The best cam curve is obtained by changing the kinemateic of the object function. The result has improved all characteristics such as velocity, acceleration and displacement compared with that of the modified cycloid curve.

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다결정 알루미나에서 결정립 크기 분포를 포함하는 Bridging 응력함수의 해석적 모델링 (An Analytical Modeling for Bridging Stress Function Involving Grain Size Distribution in a Polycrystalline Alumina)

  • 손기선;이성학;백성기
    • 한국세라믹학회지
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    • 제31권12호
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    • pp.1449-1458
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    • 1994
  • A new analytical model which can discribe the relationship between the bridging stress and the crack opening displacement was proposed to investigate the microstructural effect on the R-curve behavior in a polycrystalline alumina. The crack opening displacement according to the distance behind the stationary crack tip was measured using in-situ fracture technique in an SEM, and then used for a fitting procedure to obtain the distribution of bridging stress. The current model and an empirical power law relation were introduced into the fitting procedure. The results indicated that the bridging stress function and R-curve computed by the current model were consistent with those computed by the power law relation. The microstructural factor, e.g., the distribution of grain size, was also found to be closely related to the bridging stress. Thus, this model explained well the interaction effect between the distribution of bridging stress and the local-fracture-controlling microstructure, providing important information for the systematic interpretation of microfracture mechanism including R-curve behavior of a monolithic alumina.

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소형펀치 시험과 역해석에 의한 재료의 유동응력 결정 (Inverse Analysis Approach to Flow Stress Evaluation by Small Punch Test)

  • 천진식
    • 대한기계학회논문집A
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    • 제24권7호
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    • pp.1753-1762
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    • 2000
  • An inverse method is presented to obtain material's flow properties by using small punch test. This procedure employs, as the objective function of inverse analysis, the balance of measured load-di splacement response and calculated one during deformation. In order to guarantee convergence to global minimum, simulated annealing method was adopted to optimize the current objective function. In addition, artificial neural network was used to predict the load-displacement response under given material parameters which is the most time consuming and limits applications of global optimization methods to these kinds of problems. By implementing the simulated annealing for optimization along with calculating load-displacement curve by neural network, material parameters were identified irrespective of initial values within very short time for simulated test data. We also tested the present method for error-containing experimental data and showed that the flow properties of material were well predicted.

Motion estimation using regions

  • Sull, Sanghoon
    • 한국통신학회논문지
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    • 제23권9A호
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    • pp.2333-2344
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    • 1998
  • We present a two step approach for estimating the motionand sturcture parameters from region orrespondences in two frames. Given four or more region corresondences on the same planar surface, the motion and planar orientation parameters are first linearly estimated based on second-order approximation of the displacement field of the image plane. Then, using this linear estimate as an initial guess, a nonlinear estimate is obtained by iteratively minimizing an objective function using the exact experession of the displacement field. The objective function involves the centroids of corresponding regions and relationships among low-order moments. Through simulations, we show that the two-step region-based approach gives robust estimates. The performance of nonlinear region-based estimation is compared with that of linear region-based and point-based methods. Experimental results for two image pairs, on esynthetic and one real, ar epresented to show the practical applicability of our approach.

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Probabilistic analysis of spectral displacement by NSA and NDA

  • Devandiran, P.;Kamatchi, P.;Rao, K. Balaji;Ravisankar, K.;Iyer, Nagesh R.
    • Earthquakes and Structures
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    • 제5권4호
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    • pp.439-459
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    • 2013
  • Main objective of the present study is to determine the statistical properties and suitable probability distribution functions of spectral displacements from nonlinear static and nonlinear dynamic analysis within the frame work of Monte Carlo simulation for typical low rise and high rise RC framed buildings located in zone III and zone V and designed as per Indian seismic codes. Probabilistic analysis of spectral displacement is useful for strength assessment and loss estimation. To the author's knowledge, no study is reported in literature on comparison of spectral displacement including the uncertainties in capacity and demand in Indian context. In the present study, uncertainties in capacity of the building is modeled by choosing cross sectional dimensions of beams and columns, density and compressive strength of concrete, yield strength and elastic modulus of steel and, live load as random variables. Uncertainty in demand is modeled by choosing peak ground acceleration (PGA) as a random variable. Nonlinear static analysis (NSA) and nonlinear dynamic analysis (NDA) are carried out for typical low rise and high rise reinforced concrete framed buildings using IDARC 2D computer program with the random sample input parameters. Statistical properties are obtained for spectral displacements corresponding to performance point from NSA and maximum absolute roof displacement from NDA and suitable probability distribution functions viz., normal, Weibull, lognormal are examined for goodness-of-fit. From the hypothesis test for goodness-of-fit, lognormal function is found to be suitable to represent the statistical variation of spectral displacement obtained from NSA and NDA.

Magneto-thermo-elastic response of a rotating functionally graded cylinder

  • Hosseini, Mohammad;Dini, Ali
    • Structural Engineering and Mechanics
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    • 제56권1호
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    • pp.137-156
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    • 2015
  • In this paper, an analytical solution of displacement, strain and stress field for rotating thick-walled cylinder made of functionally graded material subjected to the uniform external magnetic field and thermal field in plane strain state has been studied. Stress, strain and displacement field as a function of radial coordinates considering magneto-thermo-elasticity are derived analytically. According to the Maxwell electro-dynamic equations, Lorentz force in term of displacement is obtained in cylindrical coordinates. Also, symmetric temperature distribution along the thickness of hollow cylinder is obtained by solving Fourier heat transfer equation in cylindrical coordinates. Using equation of equilibrium and thermo-mechanical constitutive equations associated with Lorentz force, a second-order inhomogeneous differential equation in term of displacement is obtained and will be solved analytically. Except Poisson's ratio, other mechanical properties such as elasticity modulus, density, magnetic permeability coefficient, heat conduction coefficient and thermal expansion coefficient are assumed to vary through the thickness according to a power law. In results analysis, non-homogeneity parameter has been chosen arbitrary and inner and outer surface of cylinder are assumed to be rich metal and rich ceramic, respectively. The effect of rotation, thermal, magnetic field and non-homogeneity parameter of functionally graded material which indicates percentages of cylinder's constituents are studied on displacement, Von Mises equivalent stress and Von Mises equivalent strain fields.