• Title/Summary/Keyword: Inverse Shape

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Estimations of Offshore Structure Damages by Modal Perturbation Method (Modal-Perturbation 기법을 이용한 항만 구조물의 손상부위 추정)

  • 조병완;한상주
    • Computational Structural Engineering
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    • v.9 no.4
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    • pp.209-217
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    • 1996
  • An Inverse modal perturbation method was applied to estimate the assessments of the damages at the large-scaled marine structure, such as pier or dolphin, from the structural dynamic natural frequencies and mode shape. Vibrations of structural stiffness, natural frequencies and mode shapes from the eigenvalue analysis lead to the modal peturbation equations, which were considered with a second order term. This paper estimates the assessments of the damages for the structure with the decreased stiffness and shows the convergence of perturbation equation.

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Inverse Approach to Study the Mechanical Properties of the Human Cornea and its Application to the Excimer Laser Surgery (역(逆)접근 방법에 의한 각막의 물성치 연구와 엑시머 레이저 수술에의 응용)

  • Huh, Jun-Young;Shin, Jung-Woog;Han, Geun-Jo
    • Proceedings of the KOSOMBE Conference
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    • v.1994 no.05
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    • pp.127-130
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    • 1994
  • This study is focused on investigating the mechanical properties of the human cornea and its shape through the inverse nonlinear finite element approach using the clinical and experimental data. The results of the inverse approach were used to construct the finite element model of the photorefractive excimer laser surgery for the myopia patients. The results of the finite element model were compared with those of the current clinical experiences and showed good agreements. Finally this study came to the conclusion that the finite element method has potential of the application to the medicine.

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Hysterersis Compensation in SMA Actuators Through Numerical Inverse Preisach Model Implementation

  • Kha, Nguyen-Bao;Ahn, Kyoung-Kwan
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2048-2053
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    • 2005
  • The aim of this paper is to compensate hysteresis phenomena in Shape Memory Alloy (SMA) actuators by using numerical inverse Preisach model. This is used to design a controller that correct hysteresis effects and improve accuracy for the displacement of SMA actuators. Firstly, hysteresis is identified by numerical Preisach model implementation. The geometrical interpretation from first order transition curves is used for hysteresis modeling. Secondly, the inverse Preisach model is formulated and incorporated in open-loop control system in order to obtain desired input-output relationship with hysteresis reducing. The experimental results for hysteresis compensation by using this method are also shown in this paper.

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Default Bayesian testing equality of scale parameters in several inverse Gaussian distributions

  • Kang, Sang Gil;Kim, Dal Ho;Lee, Woo Dong
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.3
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    • pp.739-748
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    • 2015
  • This paper deals with the problem of testing about the equality of the scale parameters in several inverse Gaussian distributions. We propose default Bayesian testing procedures for the equality of the shape parameters under the reference priors. The reference prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. Therefore we propose the default Bayesian testing procedures based on the fractional Bayes factor and the intrinsic Bayes factors under the reference priors. Simulation study and an example are provided.

Improvement of the Performance of Hysteresis Compensation in SMA Actuators by Using Inverse Preisach Model in Closed - Loop Control System

  • Ahn Kyoung-Kwan;Kha Nguyen-Bao
    • Journal of Mechanical Science and Technology
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    • v.20 no.5
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    • pp.634-642
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    • 2006
  • The aim of this paper is to increase the performance of hysteresis compensation for Shape Memory Alloy (SMA) actuators by using inverse Preisach model in closed-loop control system. This is used to reduce hysteresis effects and improve accuracy for the displacement of SMA actuators. Firstly, hysteresis is identified by numerical Preisach model implementation. The geometrical interpretation from first order transition curves is used for hysteresis modeling. Secondly, the inverse Preisach model is formulated and incorporated in closed-loop PID control system in order to obtain desired current-to-displacement relationship with hysteresis reducing. The experimental results for hysteresis compensation by using this method are also shown in this paper.

A method to determine moment of inertia properties of an arbitrary shape body by modal testing (모우드 측정을 이용한 관성 모우멘트 도출)

  • 박윤식;정경렬;홍성욱;전혁수;이종원
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.102-107
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    • 1986
  • This paper presents a new idea to obtain moment of inertia values of an arbitrary shape body by applying inverse modal transformation technique. A multiaxes inertia pendulum apparatus was designed to measure 6 rigid body modes of a test body. A software was developed to calculate inertia properties as well as the location of center of gravity and total mass of the test body from the measured modal data. The developed method was applied to a simple body of which the inertia properties are known then the obtained values were compared with the known values.

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A study of mechanical properties and development of intelligent composite using TiNiCo shape memory alloy (TiNiCo 형상기억복합재료의 기계적특성에 관한 연구)

  • 박영철;한근조;박동성
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.465-469
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    • 1997
  • In this paper, shape memory compsites are made by powder metallurgy. And then, an self-strengthening effect of the composites by shape memory effect above inverse transformation temperature A/sab f/ of TiNi alloy discussed. Moreover, TiNiCo/Al composite is made by using TiNiCo alloy as fiber. And it is discused aboutaffection of Co in the shape memory composite. The results of the intelligent properties of TiNi/Ai-radical shape memory composite, using SMA, by powder metallurgy are the tensile strength of TiNiCo wire is much higher than that of TiNi wire. and the strength of TiNiCo/Al composite is generally higher than that TiNi/Al composite.

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Analysis of Practical Dynamic Force of Structure with Inverse Problem (역문제에 의한 구조물의 실동하중 해석)

  • 송준혁;노홍길;김홍건;유효선;강희용;양성모
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.2
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    • pp.75-80
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    • 2004
  • Vehicle structures are composed of many substructure connected to one another by various types of mechanical joints. In vehicle engineering it is important to study these connected structures under various dynamic forces for the evaluations of fatigue life and stress concentration exactly. It is difficult to obtain the accurate load history of specified positions because of the errors such as modeling, measurement and etc. In the beginning of design exact load data are actually necessary for the fatigue strength and life analysis to minimize the cost and time of designing. In this paper, the procedure of practical dynamic force determination is developed by the combination of the principal stresses of F. E. Analysis and experiment. Least square pseudo inverse matrix is adopted to obtain in inverse matrix of analyzed stresses matrix. The error minimization method utilizes the inaccurate measured error and the shifting error that the whole data is stiffed over real data. The least square criterion is adopted to avoid these non. Finally, to verify the proposed procedure, a bus is analyzed. This measurement and prediction technology can be extended to the structural modification of any geometric shape in complex structure.

Radiation Heat Flux and Combustion Characteristics of Inverse Diffusion Flame Burner Using Synthesis Gas, Part 1 : Air-Fuel Combustion (합성가스를 이용한 역확산버너의 연소 및 복사열전달 특성, Part 1 : 공기-연료 연소)

  • Lee, Pil-Hyong;Park, Chang-Soo;Lee, Jae-Young;Park, Bong-Il;Hwang, Sang-Soon;Lee, Sung-Ho;Anh, Yong-Soo
    • Journal of the Korean Society of Combustion
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    • v.14 no.4
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    • pp.33-40
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    • 2009
  • Waste Thermal Pyrolysis Melting process was proposed and has been studied in order to prevent air pollution by dioxin and fly ash generated from combustion process for disposal of waste. In this study, applicability as the fuel of diffusion burner of synthesis gas formed from Waste Thermal Pyrolysis process was addressed. Results showed that there is no big difference in the flame shape between MNDF and SNDF, and lift off was detected in MIDF but flame is more stable in SIDF which contains hydrogen with high combustion velocity as flow rate in first nozzle is increased. And radiation heat flux in inverse diffusion flame of synthesis gas was found to be more by 1.5 times than that in inverse diffusion flame of methane because of higher mole fraction of $CO_2$ with high emissivity in product gas.

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