• 대한안전경영과학회지
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• 제3권3호
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• pp.221-230
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• 2001

The assembly tolerance design methods have applied linear or nonlinear programming methods and used simulation method and search algorithms to optimize the tolerance allocation of each part in an assembly. However, those methods are only considered to the relationship between tolerance and manufacturing cost, which do not consider a quality loss cost for each part tolerance. In this paper, the integrated simulation model used genetic algorithm and the Monte-Carlo simulation method was developed for the allocation of the optimal tolerance considering the manufacturing cost and quality loss cost.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.309-312
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• 2002

For the purpose of more effective simulation of the utility interactive WPGS(Wind Power Generation System) the SWRW (Simulation method for WPGS using Real Weather condition) is used in this paper, in which those of three topics for the WPGS simulation. user-friendly method, applicability to grid-connection and the utilization of the real weather conditions, are satisfied. The simulation of the WPGS using the real weather condition including components modeling of wind turbine system is achieved by introducing the interface method of a non-linear external parameter and FORTRAN using PSCAD/EMTDC. The simulations of steady-state and transient-state are performed effectively by the introduced simulation method. The generator output and current supplied into utility can be obtained by the steady-state simulation, and THD can be achieved by analyzing the results as well. The transient - state of the WPGS can be analyzed by the simulation results of over cut-out wind speed.

• 전기전자학회논문지
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• 제22권1호
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• pp.98-103
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• 2018

차세대 반도체로 각광받고 있는 CNTFET은 기존 MOSFET의 Source와 Drain 사이에 CNT를 배치하여 그 성능을 향상시킬 수 있는 구조를 가지고 있으나, 다양한 CNT 배치로 인한 CNTFET의 구조적 변화는 소자 성능에 대한 해석의 복잡도를 증가시켜, 공정 편차가 반도체 소자 성능에 미치는 영향을 분석하고자 할 때, 기존의 MOSFET에 비해 보다 많은 계산을 요구하는 문제점을 가지고 있다. 이러한 문제점은 공정편차 분석에 필요한 시뮬레이션 시간을 급격하게 증가시키고 기존 툴(tool)로 분석할 수 없는 경우를 포함하고 있어 CNTFET으로 회로를 디자인 하는데 중요한 걸림돌로 작용하고 있다. 본 연구에서는 시뮬레이션의 급격한 증가를 해결하기 위한 방법으로서 기존 Linear Programming이 활용될 수 있음을 보이고 그 효과에 대해 자세히 논의하고자 한다. 시뮬레이션 결과 CNT 최대 배치수가 6에서 12까지 증가할 때, Linear Programming 방법은 시뮬레이션 횟수를 약 2.5배 감소시킬 수 있음을 보이고 있다.

• 대한기계학회논문집
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• 제7권1호
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• pp.11-18
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• 1983

For the steady-state solutions of vibratory systems where the dynamics involves nonlinearity and discontinuity, a method of numerical simulation has been normally used. This paper presents a new approach which may overcome some difficulties in the simulation method. This approach is based on the fundamental assumption that the steady-state forced vibration is periodic, so that the problem is formulated as a two-point boundary-value problem and can be solved by Waner's algorithm. This method is demonstrated through the solutions of a linear system, a system with Coulomb friction and an impact pair. It is found that the method gives true solutions well both for linear and nonlinear systems, which convinces us of the usefulness of the method.

• 한국조경학회지
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• 제23권1호
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• pp.23-38
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• 1995

ELEECTRE is a less demanding and potentially Bffective multiattribute evaluation method for pre-editing proeedure. The method, however, was developed based on probabilistic mathematicsand its reliability has never'been emprieally tested. This article examined the reliability of ELECTRo under various conditions of linear and non-linear utility func- tions using a Monte-Carlo shnulation, and found the method eausea a considerably high rate of error. To enhance the reliability of ELECTRE, two ways of modi(ication - adjust- ment of threshold values of concordance and discordance matrices, and adjustment of the required nunlber of probably-dominant alternatives to eliminate a probably-dominated alternative - were suggested, and their effctiveness was also tesed by a Monte-Carlo simulation. The simulation result chows that these modifications cponsiderably improve the reliability of ELECTRE, and yet maintain a reasonably high level of efficiency. Through these modifications, ELECTRE can be used as an efficient and feliable pre-editing method. Ways to implement ELECTRE in the construction of plainning decision support systens were discussed. The impli(els combination of this method and other multiattribute evaluation methods will help to create more effective decision suport systems.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권10호
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• pp.637-645
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• 2000

This study was represented the improvement of the flexible position control for linear motion of hybrid type linear pulse motor(HLPM). The driving method used a minute 125 microstep drive instead of full step drive method. The digital control method was applied to the PI control for more stable position control, at this time the PI control parameters have gained by a Ziegler-Nichols turning method. The loop transfer function of control system was combined with both motor transfer function and digital PI control equation. Such, the proper for digital PI control system is verified to through the simulation and experimental result of the stability step response and bode plot with proper gain and phase margin.

• 한국군사과학기술학회지
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• 제7권2호
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• pp.32-40
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• 2004

In this paper, a simulation model for FLAS(Fixed Linear Arrays System) is presented and methods for effectiveness analysis are studied to analyze the valid target detection effectiveness of this system. The simulation model is constructed taking the FLAS operational specification into account, and thus the change in system specification is effectively reflected on the simulation results. The computational burden is reduced by using the pre-processed simulation parameters which are calculated from the real environmental database. Also, the cell effectiveness and TMOE(Total Measurement of Effectiveness) are computed. The target detection effectiveness of FLAS can be simulated under the multiple target interference simulation. It is shown that the presented algorithm is suitable for the underwater system which needs the simulation model for the optimum system design.

• 전기학회논문지
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• 제64권4호
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• pp.567-572
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• 2015

Discharge characteristics of linear microwave plasma were investigated by using fluid simulation of 2D axis-symmetry based on finite elements method. The microwave power was 2.45 GHz TEM mode and transmitted through linear antenna. Resistive power and pressure were considered simulation variables and argon was used for working gas. A decrease of electron density along the quartz tube was observed in low power condition but relatively uniform plasmas were generated in chamber by increasing the resistive power. The electron temperature was highly detected near the surface of quartz tube because the electron was heated only dielectric surface. The power transmission efficiency decreased and characteristics of surface plasma were observed in high electron density condition.

• International Journal of Railway
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• 제9권2호
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• pp.41-45
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• 2016

In this paper, a study on the efficiency improvement of the magnetic levitation train using the LIM (Linear Induction Motor) was presented. The maglev train has the advantage of being environmentally friendly since much less noise and dust is produced. However, due to structural limitation, compared to a rotating induction motor, linear induction motor, the main propulsion engine of the maglev train has a relatively greater air gap and hence has the lower operation efficiency. In this paper, the relationship between the operating condition of the train and the slip frequency has been investigated to find out the optimum slip frequency that might improve the efficiency of the magnetic levitation train with linear induction motor. The slip frequency is variable during the operation by this relationship only within a range that does not affect the levitation system of the train. After that, the comparison of the efficiency between the conventional control method with the slip frequency fixed at 13.5[Hz] and the proposed method with the slip frequency variable from 9.5[Hz] to 6.5[Hz] has been conducted by simulation using Simplorer. Experiments of 19.5[ton] magnetic levitation trains owned by Korea Institute of Machinery and Materials were carried out to verify the simulation results.

• 한국시뮬레이션학회논문지
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• 제14권3호
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• pp.129-136
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• 2005

We develop a variance reduction technique applicable in one simulation experiment whose purpose is to estimate the parameters of a first order linear model. This method utilizes the control variates obtained during the course of simulation run under Schruben and Margolin's method (S-M method). The performance of this method is shown to be similar in estimating the main effects, and to be superior to S-M method in estimating the overall mean response in a given model. We consider that a proposed method may yield a better result than S-M method if selected control variates are highly correlated with the response at each design point.