• Journal of Power System Engineering
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• v.6 no.3
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• pp.64-70
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• 2002

A fast decoupled algorithm for time domain simulation of power electronics circuits is presented. The circuits can be arbitrarily configured and can incorporate feedback amplifier circuits. This simulation algorithm is performed for the input series output parallel connected 2 switch forward converter. Steady state and large signal transient responses due to a step load change are simulated. The simulation results are verified through experiments.

• Proceedings of the Korea Society for Simulation Conference
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• 1998.10a
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• pp.199-203
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• 1998

Process planning and scheduling are traditionally regarded as separate tasks performed sequentially. But if two tasks are performed concurrently, greater performance can be achieved. In this study, we propose new approach to integration of process planning and scheduling. We propose new process planning combinations selection method using simulation based genetic algorithms. Computational experiments show that proposed method yield better performance when compared with existing methods.

• Journal of the Korea Society for Simulation
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• v.22 no.4
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• pp.11-19
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• 2013

The Korean naval weapon systems, combat experiments establish the concept of Battle operations, and create the future of the new weapons system. Doctrine development and training as well as ranging from experiments for evaluate the performance of mission operations for combat experiments are used. The battle lab is effectively support tool for the Korean Naval battle experiments. The battle lab is through a dedicated testing facility and to build efficient and effective simulation-based acquisition supporting environment. In this paper, the ship / submarines C2 operations virtual simulator was developed to support the concept of Battle operations of naval combat experiments in training and tactical development. The ship C2 operations virtual simulator makes the anti-ship and anti-aircraft the engagement scenario for performed experiments using the SADM. The submarines C2 operations virtual simulator makes the anti-submarine engagement scenario for performed experiments using EAS. EAS System was created before reuse. EAS system by modifying the additional interfaces HLA-RTI has been reused. Reflected in the tactics and training after analysis of the results through the battle experiment. Also increase training fidelity through operator involvement. The anti-ship and anti-aircraft system architecture (SADM) and anti-submarine system architecture (EAS) requires unique design of system framework since two separate architectures should be integrated into a system. An C2 virtual linked architecture was used to integrate different system architecture. A C2 virtual linked software framework, designed that have integrated protocol for battle experimental linkage and battlefield visualization environment.

• Atmosphere
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• v.25 no.1
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• pp.99-115
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• 2015

To investigate the influences of the observational nudging and the analysis nudging on the WRF simulation for the heavy snowfall event in Yeongdong area on 26 February 2012, the sensitivity experiments in relation to nudging effects were conducted. We initially set the magnitude of nudging coefficient of $6.0{\times}10^{-4}s^{-1}$ to apply to the analysis nudging experiments and observational experiments. To select the optimized options for the observational nudging, the radius influence experiment was carried out with radii ranging from 10 to 25 km at 5 km intervals. Among the observational nudging experiments, the experiment, which was conducted with the option of the radius influence of 15 km and that of the nudging coefficient of $6.0{\times}10^{-4}s^{-1}$ (ONG exp.), showed a best result. As giving the nudging effect only directly on D1 and D2 brought about a better result for the analysis nudging, we set the analysis nudging experiment as above (ANG exp.). We compared and analyzed the results from the control experiment, ONG experiment, and ANG experiment to reveal nudging effects. It was found that the control experiment brought about a result that it overestimated its precipitation in comparison with the observation and failed to properly simulate the time zone of rainfall concentration. When either of the two nudging (observational and analysis nudging) was applied to the data assimilation, it brought about a better result than the control experiment. Especially the observational nudging led to a meaningful result for the wind field, while the analysis nudging had the best result for the precipitation distribution among the experiments.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.4
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• pp.372-383
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• 2016

This study aimed at analyzing the sensitivity of ozone simulation in accordance with the meteorological nudging for a high nocturnal ozone episode. To demonstrate the effectiveness of nudging methods (e.g., nudging techniques and application domains), the following six experiments were designed: (1) control without nudging, (2) experiment with application of observation nudging to all domains (domain 1~4), and (3)~(6) experiments with application of grid nudging to domain 1, domain 1~2, domain 1~3 and all domains, respectively. As a result, the meteorological nudging had a direct (improvement of input data) and indirect (estimate natural emission) effect on ozone simulation. Nudging effects during the daytime were greater than those during the nighttime due to low accuracy of wind direction during the nighttime. On comparison of the nudging techniques, the experiments in which grid nudging was applied showed more improved results than the experiments in which observation nudging was applied. At this time point, the simulated concentrations were generally similar to the observed concentrations due to the increase in the nudging effect when grid nudging was applied up to the sub-domain. However, for high nocturnal ozone uptakes, the experiment in which grid nudging was applied do domain 1~3 showed better results than the other experiments. This is because, when grid nudging was applied to the high resolution domain (e.g., domain 4 with 1 km), the local characteristics were removed due to the smoothing effects of meteorological conditions.

• The Journal of the Acoustical Society of Korea
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• v.38 no.2
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• pp.200-206
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• 2019

In this paper, the characteristics of receiving voltage sensitivity about acoustic package in towed array sonar is analyzed through the numerical simulation and design of experiments. Simulation results show that the variation of receiving voltage sensitivity is caused by the structural resonance mode shape on baseline acoustic package. The effect of design parameters of the acoustic package are analyzed through the design of experiments to reduce the deviation of receiving voltage sensitivity. A change of hydrophone shield can thickness (t) is the greatest effect on the deviation of receiving voltage sensitivity. As a result of water tank test, the acoustic package derived from the design of experiments has reduced deviation of receiving voltage sensitivity.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.4
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• pp.424-434
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• 2016

A few blast experiments are conducted to investigate the behavior of one-way reinforced concrete(RC) slabs under blast loading. Reflected blast characteristics as well as displacements and damage patterns of RC slabs are measured. Numerical models are also established in the software ANSYS AUTODYN to reproduce the experiments on RC slabs. The numerical models are distinguished from each other by different boundary conditions at the edges of RC slabs, which are assumed to reproduce displacements and damage patterns resulted from the experiments. The boundary condition of the experimental tests is estimated from the numerical simulation results. From the numerical simulation results, the boundary condition should be improved in order to measure the accurate maximum displacement in the experimental tests.

• Journal of Mechanical Science and Technology
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• v.16 no.5
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• pp.619-632
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• 2002

In recent study on design of experiments, the complicate metamodeling has been studied because defining exact model using computer simulation is expensive and time consuming. Thus, some designers often use approximate models, which express the relation between some inputs and outputs. In this paper, we review and compare the complicate metamodels, which are expressed by the interaction of various data through trying many physical experiments and running a computer simulation. The prediction model in this paper employs interpolation schemes known as ordinary kriging developed in the fields of spatial statistics and kriging in Design and Analysis of Computer Experiments (DACE) model. We will focus on describing the definitions, the prediction functions and the algorithms of two kriging methods, and assess the error measures of those by using some validation methods.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.364-369
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• 2002

Presently, a high frequency switching technique is used for a converter design to reduce its size and weight. However an increased switching frequency introduces a high switching loss. To the reduce switching loss, soft switching techniques using ZVS and ZCS are applied. It is very important to improve efficiency. However In general to develop new converter circuits, the efficiency and other performance parameters can be determined after design, implementation and experiments. The idea in this paper is to determine and predict efficiency and other operating characteristics without realization and experiments. Thereby a complex design and implementation can be avoided. PSPICE is used as a simulation tool. This is verified by comparing simulation and experiments results of the two different soft switching converters.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.905-906
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• 2006

This paper deals with the dynamic simulations and experiments of moving-coil linear actuator with/without spring. Dynamic simulation algorithm is established from the voltage and motion equation. Finally, for various values of frequency, dynamic simulation results for characteristics of current and displacement of moving-coil linear actuator with and without spring are presented and confirmed through the experiments.