• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1997년도 추계 학술대회논문집
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• pp.113-119
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• 1997

This paper addresses to the injection pressure effect on the diesel spray. The injection pressure is varied from 10MPa, in general system, upto 200MPa, in high pressured system in order to understand the effect. The gas phase is modelled in terms of the Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction. The liquid phase is modelled following the discrete droplet model approach in Lagrangian form. The droplet distributions, vapor fractions and gas flows are analyzed in various injection pressure cases.

• 대한전기학회논문지
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• 제41권3호
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• pp.219-226
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• 1992

In this study, Kalman filtering theory is applied to the estimation of symmetrical components from fault voltage and current signal when it comes to faults with the power system. An algorithm for estimating fault location accurately and quickly by calculating the symmetrical components from the extracted fundamental voltage phasor and current phasor is presented. Also, to confirm the validity of digital distance relaying techniques using Kalman filtering, the experimental results obtained by using the digital simulation of power system is shown.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제22권3호
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• pp.201-215
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• 2018

In this paper we consider a class of singularly perturbed system of delay differential equations of convection diffusion type with integral boundary conditions. A finite difference scheme on an appropriate piecewise Shishkin type mesh is suggested to solve the problem. We prove that the method is of almost first order convergent. An error estimate is derived in the discrete maximum norm. Numerical experiments support our theoretical results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.909-912
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• 1988

This paper proposed the new control law which is defined by instantaneous output and time delayed output. To analyze the system with time delayed output, the way which transforms output time delayed systems into instantaneous output systems is presented. The output responses were more improved by the new control law then that of the instantaneous output control law. The algorithm for simulation and a numerical example are presented.

• 대한전기학회논문지:전력기술부문A
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• 제48권7호
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• pp.898-902
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• 1999

In this paper, we proposed an algorithm for estimating parameters of nonlinear continuous-discrete state-space system. This algorithm uses the conventional extended Kalman filter(EKF) for estimating state variables, and modifies the recursive prediction error method for parameter estimation of the nonlinear system. Simulation results for both linear and nonlinear measurements under the environment of process and measurement noises show a convincing performance of the proposed algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.638-640
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• 1998

This paper discusses approximation modelling of discrete-time linear time-varying system(LTVS). The wavelet theory and genetic algorithm are considered as a tool for representing and approximating a LTVS. The joint time-frequency properties of wave analysis are appropriate for describing the LTVS. Simulation results is included to illustrate the potential application of the technique.

• ETRI Journal
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• 제6권1호
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• pp.3-9
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• 1984

This paper presents a direct adaptive poleplacement control scheme which is applicable to discrete-time non-minimum phase systems. It is proved that by this scheme the poles can be placed at the desired locations and the overall state vector of the system is uniformly bounded if the reference input is sufficiently rich, and also proved that in case of insufficiently rich reference input the overall system can still be stabilized though the poles may not be placed exactly at the desired locations. The effectiveness of this scheme is verified by digital computer simulations.

• 대한전기학회논문지
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• 제32권6호
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• pp.219-224
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• 1983

The problem of model reference adaptive control for the discrete time system is considered and the global stability of the overall system is shown. It extends the results of Kreisselmeier's to more general reference models and the method presented here makes the output error and controller parameter error converge to zero. The scheme presented in this paper is simulated and the simulation gives the expected results.

• 대한전기학회논문지
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• 제33권2호
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• pp.56-61
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• 1984

The problem of model reference adaptive control for the discrete time system is considered and the global stability of the overall system is shown. It extends the results of Choi's to the plants and models whose transfer functions have arbitrary gains and the method presented here makes the output error and the conftroller parameter error converge to zero. The scheme presented in this paper is simulated and gives good results.

• 대한전기학회논문지
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• 제37권4호
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• pp.220-225
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• 1988

A class of adaptive controllers with integral action is proposed, which may riject the offset due to any load disturbance on the plant. Effective integral action and robust identification against the offset can be achieved via the zero-gain predictor. The system is improved, in this paper, to be of more generalized structure, and the detuning control weight which can cope with nonminimum-phase systems is tuned on-line. Discrete-time versions of the improved system are developed, which may be more flexible for the choice of the design parameters. The resulting control systems may also be shown to be robust to the unmodelled dynamics.