• 한국안전학회지
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• 제31권4호
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• pp.143-149
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• 2016

In this study, a series of numerical simulation of dam break flow was conducted using EFDC model, and input conditions including cell size, time step, and turbulent eddy viscosity were considered to analyze parameter sensitivity. In case of coarse mesh layout, the propagated length of the shock wave front was ${\Delta}_x$ longer than that of other mesh layouts, and the velocity results showed jagged edge, which can be cured by applying fine grid mesh. Turbulent eddy viscosity influenced magnitude of the maximum velocity passing through gate up to 20% and the cell Peclet number less than 2.0 ensured no numerical oscillations.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 연구회 합동 학술발표회 논문집
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• pp.55-59
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• 1998

By this time, Diode Rectifier or SCR has been used to gain DC Voltage for Electrolysis Power. Generally DC Voltage is produced from rectifier shall be transformed before rectifier using step-down transformer to obtain adaptable DC Voltage, rectifier output. In the same way, rectifier using SCR shall obtain output voltage after step-down voltage through transformer and control of the SCR firing angle. Transformer shall be used for this two methods to adjust the voltage. But the size and weight of the transformer are increased in accordance with the increase of capacity, and the hardships are accompanied in workspace or transportation. Besides, only the value of input voltage is possible to be regulated, and the expectation of current control is almost impossible during Electrolysis. This study has conducted Design and Simulation to reduce the size and weight of transformer and to be enable voltage and current control of Electrolysis power through high-speed switching using Inverter, Electronics device.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.70-72
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• 2009

In this paper, nonlinear active noise control(ANC) of a 3rd-order Volterra system, which is robust to background noise variation, is proposed along with a variable step-size Gauss-Seidel pseudo affine projection(VSSGS-PAP) algorithm. Simulation results demonstrate that the proposed approach yields better nonlinear ANC performance in a background noise variation environment, compared with the conventional methods for the nonlinear ANC.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.823-828
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• 1992

A novel steepest descent adaptive filter algorithm, which uses the instantaneous stochastic gradient for the steepest descent direction, is derived from a newly devised performance index function. The performance function for the new algorithm is improved from that for the LMS in consideration that the stochastic steepest descent method is utilized to minimize the performance index iterativly. Through mathematical analysis and computer simulations, it is verified that there are substantial improvements in convergence and misadjustments even though the computational simplicity and the robustness of the LMS algorithm are hardly sacrificed. On the other hand, the new algorithm can be interpreted as a variable step size adaptive filter, and in this respect a heuristic method is proposed in order to reduce the noise caused by the step size fluctuation.

• 한국연초학회지
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• 제20권1호
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• pp.87-94
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• 1998

After we made the computer source code with mathematical model of Muramatsu et al. that was expressed by the set of simultaneous first-order ordinary differential equations in evaporation-pyrolysis zone of cigarette, we simulated the distribution profiles of temperature and density of flue-cured tobacco. Those equations were solved numerically with the Runge-Kutta-Gill algorithm assuming step size of 0.025mm by Muramatsu at at,, but in this study the advanced algorithm of Runge-Kutta 4th Order assuming step size of 0.0005mm. The initial conditions and physical parameters of Muramatsu et at. were used for solving them. The calculated values corresponded well with results of Muramatsu et al., especially the gradient of the temperature profile increased with smoldering speed and the thickness of the evaporation-pyrolysis zone decreased with increasing of smoldering speed. On the other hand, the temperature gradient decreased with increasing of the effective thermal-conductivity value and the thickness of the evaporation-pyrolysis zone increased with the effective thermal-conductivity value.

• 전자공학회논문지S
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• 제34S권4호
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• pp.42-49
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• 1997

A conventional adaptive noise canceller (ANC) using LMS algorithm suffers from the misadjustment of adaptive filter weights due to the gradient-estimate noise by input speech signal at steady state. In this paper, an ANC is proposed which uses the combination of VSLMS (variable step size LMS) and SA (sign algorithm) to improve steady state performance and convergence rate. SA algorithm is applied in speech region to prevent the weights from perturbing by output speech of ANC and VSLMS algorithm is applied to improve convergence rate and channel tracking ability in silence region and adaptive transient region. In compute rsimulation, the performance of the proposed VSLMS-SA combination algorithm is much better than LMS algorithm and the algorithm, recently proposed by greenberg, with adaptation step-size parameter determine dby sum method in convergence rate, channel tracking and steady state performance.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 춘계 종합학술대회 논문집
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• pp.369-373
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• 2005

본 논문은 기존의 주파수 영역 독립 성분 분석(FDICA : frequency domain independent component analysis) 방법에 가변 적응 상수를 이용한 알고리즘을 제안한다. 여러 반향 환경에 대한 모의실험으로 기존의 temporal structure(TA)알고리즘, FDICA알고리즘과 비교하여 그 분리 성능을 평가하고 비교한다. 실제 녹음한 혼합 음원에 대한 분리정도를 비교 분석한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.565-567
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• 2010

This paper proposes a new Maximum Power Point Tracking (MPPT) control algorithm for PV-Cell (Photo voltaic) based on Incremental Conductance MPPT algorithm. The ICN (Incremental Conductance method) algorithm is widely used due to the high tracking accuracy and adaptability to the rapidly changing isolation condition. In this paper, a modified ICN MPPT algorithm is proposed. This method adjusts automatically the step-size of reference to track the PV-Cell maximum power point, thus it improves the maximum power point tracking speed and accuracy.

• 한국통신학회논문지
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• 제15권8호
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• pp.689-697
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• 1990

본 논문에서는 기존의 이중 케이블에서 전 이중방식 디지털 데이터 전송을 위한 적응 스토캐스틱 반복 알고리즘(Adaptive Stochasti Iteration Algorithm)을 제안하였다. 이 알고리즘을 이용한 반향제저기의 Step size는 반향의 크기에 따라서 변하므로 기존의 알고리즘에 의한 것 보다 10 배 이상의 높은 수렴율을 보였다. 그리고 이것은 기존의 반향 제거기 회로를 단순화 시키는 시퀸스 형태의 적응 디지털 필터와 결합하여 구현되며 LSI 수준으로 구현하기에 적합하다. 두 알고리즘에 대한 이론적인 분석을 제시하고 시뮬레이션 프로그램을 개발하였다.

• 천문학회지
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• 제39권4호
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• pp.147-150
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• 2006

In this paper, initial value problem for dynamical astronomy will be established using parabolic cylindrical coordinates. Computation algorithm is developed for the initial value problem of gravity perturbed trajectories. Applications of the algorithm for the problem of final state predication are illustrated by numerical examples of seven test orbits of different eccentricities. The numerical results are extremely accurate and efficient in predicating final state for gravity perturbed trajectories which is of extreme importance for scientific researches as well as for military purposes. Moreover, an additional efficiency of the algorithm is that, for each of the test orbits, the step size used for solving the differential equations of motion is larger than 70% of the step size used for obtaining its reference final state solution.