• Journal of the Korean Magnetic Resonance Society
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• v.10 no.1
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• pp.1-37
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• 2006

General expressions for solid state NMR lines are described for transitions under static, magic angle spinning, and variable angle spinning conditions in the case where the principal axis system for the anisotropic chemical shift tensor is noncoincident with that of the quadrupole coupling tensor. It is demonstrated that solid state NMR powder pattern simulation program VMAS based on the conventional grid point method of integrating over the Euler angle space is fast enough in comparison with the POWDER simulation package and Gauss-point method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.04a
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• pp.214-224
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• 1991

The porpose in this study is to simulate te force required in the measurement of the performance of the equipments or testipieces. For the simulation of the required force, the difference in eachchamber pressure in the hydraulic cylinder was controlled with Variable Structure Control (VSC) theory. Also, nonlinear Variable Structure Observer (VSO) was designed to estimate the derivative of the load pressure which is necessary to determine the sliding surface in VSC theory. In this paper, the digital computer simulation and experiments were executed.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.846-848
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• 2000

In the early development of wind energy, the majority of wind turbines were operated at constant speed. Recently, the number of variable-speed wind turbines adopted pitch control apparatus has increased. This paper deal with a simulation of pitch control of variable-speed wind turbine and the response of pitch angle is traced in a given random wind speed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.596-602
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• 2008

This paper presents the dynamic characteristic analysis of Permanent Magnet Linear Synchronous Motor(PMLSM) according to variable load. In order to analyze dynamic characteristics, finite element method(FEM) was used for calculation of the parameter and the Matlab simulink was used for dynamic characteristic simulation. The measuring system of the dynamic characteristics was manufactured and the experiment results were compared with the simulation results.

• Journal of Power Electronics
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• v.19 no.1
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• pp.44-57
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• 2019

Recently, the use of LLCL filters for grid inverters has been suggested to give better harmonic attenuation than the commonly used L and LCL filters, particularly around the switching frequency. Nevertheless, this filter is mainly designed for constant switching frequency pulse width modulation (CSF PWM) methods. In variable switching frequency PWM (VSF PWM), the harmonic components are distributed across a wide frequency band which complicates the use of a high order filter, including LCL and LLCL filters. Recently, a confined band variable switching frequency (CB-VSF) PWM method has been proposed and demonstrated to be superior to the conventional constant switching frequency (CSF) PWM in terms of switching losses. However, the applicability of LLCL filters for this type of CB-VSF PWM has not been discussed. In this paper, the authors study the suitability of an LLCL filter for CB-VSF PWM and propose design guidelines for the filter parameters. Using simulation and experimental results, it is demonstrated that the effectiveness of an LLCL filter with CB-VSF PWM depends on the parameters of the filters as well as the designed variable frequency band of the PWM. Simulation results confirm the performance of the suggested LLCL design, which is further validated using a lab scale prototype.

• Journal of Multimedia Information System
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• v.8 no.1
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• pp.69-74
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• 2021

This paper accumulates the product structure data such as bond obligation ratio and investment ratio for variable insurance using crawling from the insurance company's API, also accumulates variable insurance income and project expenses for variable insurance using crawling from the API of life insurance association. From these accumulated data, the correlation coefficient between fund product and customer preference is calculated with an investment algorithm, and variable insurance funds by customer investment preference and product structure are recommended according to market conditions. From the simulation results, it is shown that the proposed variable insurance management system properly recommends and manages variable insurance according to customer preferences.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.250-252
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• 2008

DC traction system generates leakage current because running rails are used in return circuit. And it is very important to estimate the leakage current to the train operation situation. Therefore this paper presents dynamic simulation technique that is very similar to the real operation situation using TPS and PSCAD/EMTDC. For this we model DC traction system included in DC substation, variable feeding circuit model and variable train model. And we extract train location and power using TPS program and use these data for dynamic simulation. Finally we can estimate leakage current to the various operation condition using dynamic simulation.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.2
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• pp.43-49
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• 2009

Many researcher uses simulation techniques for understanding the phenomenon and expecting the response. Simulation techniques have many advantages which is less time-consuming, easy to control constraints, and cheaper than experimental study. However Researches usually are not good at programming the model, it's hard to implement simulation model using computer language. They use spreadsheet program like Microsoft $excel^{TM}$ Although a spreadsheet program is good for modeling, it's cumbersome to describe expressions which consist of not variable name but location indicator. This study suggests the program which helps researcher developing model using graphical interface and variable name. For verifying usability, the model which is implemented by developed modeler were compared with by spreadsheet program.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.6
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• pp.1026-1030
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• 2011

This paper presented here contains development of variable stability system(VSS) control laws for the KIFS (Korean In-Flight Simulator) aircraft to simulate the dynamics of F-16 aircraft. Development of VSS Control law for pitch rate, roll rate, yaw rate simulation for three specified flight conditions using Model Following Technique with rate feedback autopilot for stability provision. The direct lift force controller was also added to the developed VSS control law to simulate the pitch rate and normal g-load simultaneously. The simulation results show high accuracy of F-16 aircraft's pitch, roll, yaw rate and g-load simulation.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.63-69
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• 1999

The research trend of the simulation optimization has been focused on exploring continuous decision variables. Yet, the research in discrete decision variable area has not been fully studied. A new research trend for optimizing discrete decision variables ha just appeared recently. This study, therefore, deals with a discrete simulation method to get the system evaluation criteria required for designing a complex probabilistic discrete event system and to search the effective and reliable alternatives to satisfy the objective values of the given system through a on-line, single run with the short time period. Finding the alternative, we construct an algorithm which changes values of decision variables and a design alternative by using the stopping algorithm which ends the simulation in a steady state of system. To avoid the loss of data while analyzing the acquired design alternative in the steady state, we provide background for estimation of an auto-regressive model and mean and confidence interval for evaluating correctly the objective function obtained by small amount of output data through simulation with the short time period. In numerical experiment we applied the proposed algorithm to (s, S) inventory system problem with varying Δt value. In case of the (s, S) inventory system, we obtained good design alternative when Δt value is larger than 100.