• Title/Summary/Keyword: Lumped Parameter Method

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Computational modeling of the coronary circulation for the assessment of the coronary artery bypass through left ventricle (좌심실을 통한 관상동맥 우회술의 평가를 위한 관상순환계의 수치적 모델)

  • Shim, Eun-Bo;Kamm, Roger D.
    • Proceedings of the KSME Conference
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    • 2000.11b
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    • pp.385-390
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    • 2000
  • In this study we propose the computational model for the coronary circulation. The bypass from left ventricle is also considered. Lumped parameter model with three compartments in the coronary circulation is implemented in this study. We connected the coronary artery compartment with left ventricle to explain the bypass procedure from left ventricle. The asymmetric resistance is assumed in the bypass line from left ventricle. The present numerical method is tested for normal coronary circulation and the results are compared with the existing computational work. The bypass simulation is conducted and the flow pattern is delineated. The effect of shunt resistance and coronary compliance to circulation is investigated for the better design of the bypass shunt.

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A study on the delay-characteristics and hankel operators of input delay systems (입력 시간지연 시스템의 한켈 연산자와 지연특성에 관한 연구)

  • Ha, Hee-Kwon;Hwang, I-Cheol;Lee, Man-Hyung
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.1
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    • pp.1-7
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    • 2000
  • This paper studies the delay-characteristics using the singular values and vectors of Hankel operators for input delay systems. First, the computational method of Hankel singular values and their corresponding singular vectors are introduced, and then it is analytically provea that all the Hankel singular vlues have a monotone increasing properties as the length of delay time increases. Furthermore, through a simple numerical example, it is shown that the Hankel singular values are dependent only on the ratio of the time constant of a lumped parameter system to the length of delay , and in case that the time constant is relatively larger than the delay time, the lumped parameter characteristic has a great influence on the input delay systems.

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Model-based Diagnosis for Crack in a Gear of Wind Turbine Gearbox (풍력터빈 기어박스 내의 기어균열에 대한 모델 기반 고장진단)

  • Leem, Sang Hyuck;Park, Sung Hoon;Choi, Joo Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.6
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    • pp.447-454
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    • 2013
  • A model-based method is proposed to diagnose the gear crack in the gearbox under variable loading condition with the objective to apply it to the wind turbine CMS(Condition Monitoring System). A simple test bed is installed to illustrate the approach, which consists of motors and a pair of spur gears. A crack is imbedded at the tooth root of a gear. Tachometer-based order analysis, being independent on the shaft speed, is employed as a signal processing technique to identify the crack through the impulsive change and the kurtosis. Lumped parameter dynamic model is used to simulate the operation of the test bed. In the model, the parameter related with the crack is inversely estimated by minimizing the difference between the simulated and measured features. In order to illustrate the validation of the method, a simulated signal with a specified parameter is virtually generated from the model, assuming it as the measured signal. Then the parameter is inversely estimated based on the proposed method. The result agrees with the previously specified parameter value, which verifies that the algorithm works successfully. Application to the real crack in the test bed will be addressed in the next study.

Optimal Control of Distributed Parameter Systems Via Fast WALSH Transform (고속 WALSH 변환에 의한 분포정수계의 최적제어)

  • Kim, Tai-Hoon;Kim, Jin-Tae;Lee, Seung;Ahn, Doo-Soo
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.50 no.10
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    • pp.464-472
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    • 2001
  • This study uses distributed parameter systems as the spatial discretization technique, modelling in lumped parameter systems, and applies fast WALSH transform and the Picard's iteration method to high order partial differential equations and matrix partial differential equations. This thesis presents a new algorithm which usefully exercises the optimal control in the distributed parameter systems. In exercising optimal control of distributed parameter systems, excellent consequences are found without using the existing decentralized control or hierarchical control method. This study will help apply to linear time-varying systems and non-linear systems. Further research on algorithm will be required to solve the problems of convergence in case of numerous applicable intervals.

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Dynamic Interaction Analysis of Tilting Train and Curved Track (틸팅열차 주행시 곡선부 궤도에서의 동적상호작용)

  • Chung, Keun-Young;Koh, Tae-Hoon
    • Journal of the Korean Society for Railway
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    • v.15 no.2
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    • pp.162-171
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    • 2012
  • In this study, a new dynamic interaction analysis method for tilting trains and curved track is presented. Three dimensional lumped parameter vehicle elements are used to model tilting train, and the proposed analysis technique can simulate driving direction change of vehicle, the effect of track cant, wheel-rail contact angle, and tilting angle of tilting trains, etc. The proposed method passed several basic verification tests, and it is expected that the suggested method is applicable for practical problems.

Adaptive Anti-Sway Trajectory Tracking Control of Overhead Crane using Fuzzy Observer and Fuzzy Variable Structure Control (퍼지 관측기와 퍼지 가변구조제어를 이용한 천정주행 크레인의 적응형 흔들림 억제 궤적추종제어)

  • Park, Mun-Soo;Chwa, Dong-Kyoung;Hong, Suk-Kyo
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.5
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    • pp.452-461
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    • 2007
  • Adaptive anti-sway and trajectory tracking control of overhead crane is presented, which utilizes Fuzzy Uncertainty Observer(FUO) and Fuzzy based Variable Structure Control(FVSC). We consider an overhead crane system which can be decoupled into the actuated and unactuated subsystems with its own lumped uncertainty such as parameter uncertainties and external disturbance. First, a new method for anti-sway control using FVSC is proposed to improve the conventional method based on Lyapunov direct method, while a conventional trajectory tracking control law using feedback linearization is directly adopted. Second, FUO is designed to estimate one of the two lumped uncertainties which can compensate both of them, based on the fact that two lumped uncertainties are coupled with each other. Then, an adaptive anti-sway control is proposed by incorporating the proposed FVSC and FUO. Under the condition that the observation error is Uniformly Ultimately Bounded(UUB) within an arbitrarily shrinkable region, the overall closed-loop system is shown to be Globally Uniformly Ultimately Bounded(GUUB). In addition, the Global Asymptotic Stability(GAS) of it is shown under the vanishing disturbance assumption. Finally, the effectiveness of the proposed scheme has been confirmed by numerical simulations.

Theoretical Approach; Identification of Dynamic Characteristics for Lumped Mass Beam Model due to Changes of Mass (질량 변화에 따른 Lumped Mass Beam Model의 이론적 동특성 규명)

  • Fawazi, Noor;Yoon, Ji-Hyeon;Kang, Kwi-Hyun;Lee, Jung-Youn;Oh, Jae-Eung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.389-392
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    • 2008
  • This paper predicts the changes of natural frequencies due to the changes of mass at different point mass stations by using iterative calculation Transfer Matrices Method for different boundary conditions of a single beam structure (fixed-free and fixed-fixed beam). Firstly, the first three natural frequencies of an original beam are obtained using Transfer Matrices Method to verify the accuracy of the obtained results. The results are then compared with the exact solutions before purposely changing the parameter of mass. Both beams are modeled as discrete continuous systems with six-lumped-mass system. A single beam is broken down into a point mass and a massless beam which represent a single station and expressed in matrix form. The assembled matrices are used to determine the value of natural frequencies using numerical interpolation method corresponding to their mode number by manipulating some elements in the assembled matrix.

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Common Model EMI Prediction in Motor Drive System for Electric Vehicle Application

  • Yang, Yong-Ming;Peng, He-Meng;Wang, Quan-Di
    • Journal of Electrical Engineering and Technology
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    • v.10 no.1
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    • pp.205-215
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    • 2015
  • Common mode (CM) conducted interference are predicted and compared with experiments in a motor drive system of Electric vehicles in this study. The prediction model considers each part as an equivalent circuit model which is represented by lumped parameters and proposes the parameter extraction method. For the modeling of the inverter, a concentrated and equivalent method is used to process synthetically the CM interference source and the stray capacitance. For the parameter extraction in the power line model, a computation method that combines analytical method and finite element method is used. The modeling of the motor is based on measured date of the impedance and vector fitting technique. It is shown that the parasitic currents and interference voltage in the system can be simulated in the different parts of the prediction model in the conducted frequency range (150 kHz-30 MHz). Experiments have successfully confirmed that the approach is effective.

A Study on Analysis of Distributed Parameter Systems via Fast Walsh Transform (고속 월쉬 변환을 이용한 분포정수계의 해석에 관한 연구)

  • Kim, Tai-Hoon;Kim, Jin-Tae;Chae, Young-Moo;Lee, Hae-Gi;Kim, Jong-Boo;Ahn, Doo-Soo
    • Proceedings of the KIEE Conference
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    • 2001.07d
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    • pp.2084-2086
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    • 2001
  • This study uses distributed parameter systems as the spatial discretization technique, modelling in lumped parameter systems, and applies orthogonal transform and the Picard's iteration method to high order partial differential equations and matrix partial differential equations. In exercising optimal control of distributed parameter systems, excellent consequences are found without using the existing decentralized control or hierarchical control method.

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An Efficient Topology/Parameter Control in Evolutionary Design for Multi-domain Engineering Systems

  • Seo, Ki-Sung
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.5 no.2
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    • pp.108-113
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    • 2005
  • This paper suggests a control method for an efficient topology/parameter evolution in a bond graph-based GP design framework that automatically synthesizes designs for multi-domain, lumped parameter dynamic systems. We adopt a hierarchical breeding control mechanism with fitness-level-dependent differences to obtain better balancing of topology/parameter search - biased toward topological changes at low fitness levels, and toward parameter changes at high fitness levels. As a testbed for this approach in bond graph synthesis, an eigenvalue assignment problem, which is to find bond graph models exhibiting minimal distance errors from target sets of eigenvalues, was tested and showed improved performance for various sets of eigenvalues.