• Title/Summary/Keyword: State equation

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Approximation of the State Variables of the Original System from the Balanced Reduced Model (발란싱축소화로 구한 축소모델로부터 원 시스템 상태변수를 구하는 방법)

  • 정광영
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.333-333
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    • 2000
  • When the generalized singular perturbation method is used for model reduction, the state variables of the original system is reconstructed from the reduced order model. The state reduction error is defined, which shows how well the reconstructed state variables approximate the state variables of the original system equation.

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Process Design of Carbon Dioxide Storage in the Marine Geological Structure: I. Comparative Analysis of Thermodynamic Equations of State using Numerical Calculation (이산화탄소 해양지중저장 처리를 위한 공정 설계: I. 수치계산을 통한 열역학 상태방정식의 비교 분석)

  • Huh, Cheol;Kang, Seong-Gil
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.11 no.4
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    • pp.181-190
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    • 2008
  • To response climate change and Kyoto protocol and to reduce greenhouse gas emissions, marine geological storage of $CO_2$ is regarded as one of the most promising option. Marine geological storage of $CO_2$ is to capture $CO_2$ from major point sources(eg. power plant), to transport to the storage sites and to store $CO_2$ into the marine geological structure such as deep sea saline aquifer. To design a reliable $CO_2$ marine geological storage system, it is necessary to perform numerical process simulation using thermodynamic equation of state. The purpose of this paper is to compare and analyse the relevant equations of state including ideal, BWRS, PR, PRBM and SRK equation of state. To evaluate the predictive accuracy of the equation of the state, we compared numerical calculation results with reference experimental data. Ideal and SRK equation of state did not predict the density behavior above $29.85^{\circ}C$, 60 bar. Especially, they showed maximum 100% error in supercritical state. BWRS equation of state did not predict the density behavior between $60{\sim}80\;bar$ and near critical temperature. On the other hand, PR and PRBM equation of state showed good predictive capability in supercritical state. Since the thermodynamic conditions of $CO_2$ reservoir sites correspond to supercritical state(above $31.1^{\circ}C$ and 73.9 bar), we conclude that it is recommended to use PR and PRBM equation of state in designing of $CO_2$ marine geological storage process.

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Training an Artificial Neural Network for Estimating the Power Flow State

  • Sedaghati, Alireza
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.275-280
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    • 2005
  • The principal context of this research is the approach to an artificial neural network algorithm which solves multivariable nonlinear equation systems by estimating the state of line power flow. First a dynamical neural network with feedback is used to find the minimum value of the objective function at each iteration of the state estimator algorithm. In second step a two-layer neural network structures is derived to implement all of the different matrix-vector products that arise in neural network state estimator analysis. For hardware requirements, as they relate to the total number of internal connections, the architecture developed here preserves in its structure the pronounced sparsity of power networks for which state the estimator analysis is to be carried out. A principal feature of the architecture is that the computing time overheads in solution are independent of the dimensions or structure of the equation system. It is here where the ultrahigh-speed of massively parallel computing in neural networks can offer major practical benefit.

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연계(連繫)된 전력계통(電力系統)의 최적(最適) 부하주파수(負荷周波數) 제어(制御)

  • Han, Man-Chun;Jang, Seong-Hwan
    • Proceedings of the KIEE Conference
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    • 1979.08a
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    • pp.119-120
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    • 1979
  • A linear state equation of the first order differential form relating the load-frequency dynamic characteristics of interconnected power systems was derived for use in computer simulation. A now solution of the algebraic matrix riccati equation for application in quadratic optimal controllor and least-square state estimator dermination was developed. The program for a dynamic state equation for two interconnected control areas was developed. The optimized load-frequency deviation was analysed and a numerical analysis was tried based on the computer simulation. It was shown that the dynamic response of th loed-frequency could be optimized with weighting factors IR and Q. The result was that the load-frequency and the tie-line deviation were visibly reduced.

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Vapor-Liquid Equilibria in Aqueous Polymer Solutions using a PRSV Equation of State (PRSV 상태방정식을 이용한 고분자 수용액 계의 기액 평형)

  • Leem, Young-Min;Kim, Mi-Kyung;Kim, Ki-Chang
    • Journal of Industrial Technology
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    • v.22 no.A
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    • pp.241-248
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    • 2002
  • In this work, we calculated the vapor-liquid equilibrium of aqueous polymer solutions by using PRSV equation of state combined with $G^{ex}$ mixing rules(HVO, MHVL, MHV2, LCVM). From the comparison of calculated results with experimental data obtained from literature, we found that calculation results by using MHV1 mixing rule have showed small range of error than HVO, MHV2 and LCVM mixing rules. Calculation results by using the combination of MHV1 mixing rule and UNIFAC-FV model have showed the best result for selected aqueous polymer solutions.

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Memory Equations for Kinetics of Diffusion-Influenced Reactions

  • Yang, Mino
    • Bulletin of the Korean Chemical Society
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    • v.27 no.10
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    • pp.1659-1663
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    • 2006
  • A many-body master equation is constructed by incorporating stochastic terms responsible for chemical reactions into the many-body Smoluchowski equation. Two forms of Langevin-type of memory equations describing the time evolution of dynamical variables under the influence of time-independent perturbation with an arbitrary intensity are derived. One form is convenient in obtaining the dynamics approaching the steady-state attained by the perturbation and the other in describing the fluctuation dynamics at the steady-state and consequently in obtaining the linear response of the system at the steady-state to time-dependent perturbation. In both cases, the kinetics of statistical averages of variables is found to be obtained by analyzing the dynamics of time-correlation functions of the variables.

Nonlinear Observer Design for Satellite Angular Rate Estimation by SDRE Method (SDRE 기법을 이용한 위성 각속도 추정용 비선형 관측기 설계)

  • Jin, Jaehyun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.10
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    • pp.816-822
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    • 2014
  • The estimation of the angular rate of a satellite has been discussed. A nonlinear observer has been proposed based on the state-dependent Riccati equation method. A sufficient stability condition for the convergence of estimation error has been presented. This condition is related to a state-dependent algebraic Riccati equation. It has been derived by transforming nonlinear error dynamics into a Lipschitz nonlinearity. An observer gain is obtained from this condition. Numerical simulations are presented to verify the proposed method.

An Experimental Study on the Vapor-Liquid Equilibria of Propane and R227ea Mixtures (프로판과 R227ea 혼합냉매의 기상-액상 평형 실험)

  • Kang, Dae-Kyung;Kim, Ju-Hyok;Kim, Min-Soo;Kim, Young-Il
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.245-249
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    • 2003
  • Vapor-liquid equilibrium data were obtained for system of propane + R227ea (Heptafluoropropane) over the temperature range from 253.15 K to 323.15 K at 10 K intervals. Experiments were performed in a circulation type apparatus by injecting vapor through liquid pool using a magnetic pump. This system forms azeotrope in the temperature range of this study. The experimental results were correlated with the Peng-Robinson (PR) equation of state and Redlich-Kwong-Soave (RKS) equation of state using the van der Walls one-fluid mixing rule and were compared with each other.

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A Sensorless PMSM Control Using the Separation of Two Voltage Source (이중전압원 분리를 이용한 PMSM의 센서리스 제어)

  • Jin-Woo Ahn;Sung-Jun Park;Dong-Hee Lee
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.53 no.1
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    • pp.1-7
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    • 2004
  • This paper presents a sensorless control strategy of a PMSM(Permanent Magnet Sycchoronous Motor). This method is very simple to compute the position angle of a rotor. A principle and a practical solution are described. A sensorless control algorithm is proposed to remove a mechanical position sensor. The theory is based on the superposition principle. The state equation of a motor is divided into two conditions: one is the state equation of exciting voltage and phase current in a constraint, the other is the state equation of back EMF(Electromotive Force) and phase current in a short circuit. Based on the analysis, short circuit current by back EMF is computed and then the information of position angle is calculated. The proposed method is verified by experimental results.

Dynamic Response of Coupled Maglev Train and Guideway System (자기부상열차-가이드웨이 통합 시스템의 동적 특성)

  • Kong, Eun-Ho;Kang, Bu-Byoung;Na, Sung-Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.2
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    • pp.137-145
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    • 2011
  • This study is proposed to develop a numerical interaction model of the magnetically levitated(maglev) train and guideway. For this purpose, equation of motion for 6-DOF vehicle model, EMS, guideway and guideway irregularity are derived as the state-space equation. In order to solve the state space equations, the present work was performed via matlab simulation using Runge-Kutta method. Through the simulation, the effect of dynamic response of maglev system to different vehicle speeds, guideway rigidity(EI) and masses is investigated.