• IE interfaces
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• v.18 no.1
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• pp.22-34
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• 2005

This paper introduces a simulation model which is based on the process analysis of a semiconductor company. The objective of the simulation modelis not only to estimate the overall performancesof the company but also to evaluate the performances of various operation rules for shop floor control. First, in order to develop the simulation model, a time study is performed for each process after analyzing the processes for the company. Second, by using ARENA, a simulation model is constructed based on the process analysis and the time study. After the simulation model is tested and run, its results are discussed.

• Water for future
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• v.13 no.4
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• pp.41-50
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• 1980

The prupose of this study are the theoretical examination of Gamma distribution function and its application to hydraulic engineering, that is studying the simulation of monthly streamflow by the Gamma distribtution function model(Gamma Model) based on Monte Carlo technique. In the analysis, monthly streamflow data in the Nak Dong River, the Han River, and the Keum River were used and the data were changed to modular coefficient in order to make the analysis convenient. At first, the fitness of monthly streamflow to 2-Parameter Gamma distribution was tested by Chi-square and Kolmogrov-Smironov test, by which it was found the monthly streamflow were fit well to this Gamma distribution function. Then, the Gamma Model based on the Gamma distribution and Monte Carlo Method was used in the simulation of monthly streamflow, and simulateddata showed that all their stastical characteristics were preserved well in the simulation. Consequently, it can be concluded that the Gamma Model is suitable for the simulation of monthly streamflow series directly by using the Mote Carlo technique.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.9-10
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• 2015

EI core inductor in power electronic circuit simulation is usually assumed as linear by using matrix model. However, nonlinear magnetic characteristics such as B-H characteristic are also important for the accurate simulation of the circuit behavior. To model nonlinear magnetic characteristics of EI core inductor with only DC bias table, this paper presents a method in PLECS simulation tool which is a commercially available simulation tool for power electronics circuit analysis. Comparing with ideal matrix model, the simplification and accuracy are improved by this modeling method. Also, compared to analysis by FEM, it is much simpler, faster and easier to simulate with power electronics circuit. Validation of the proposed model was verified by simulation and experiment results.

• Journal of the Korea Society for Simulation
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• v.25 no.3
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• pp.15-28
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• 2016

It is necessary to analyze underwater acoustics channel(UAC) modeling and simulation for underwater weapon system development and acquisition. In order to analyze UAC, there are underwater acoustics propagation numerical analysis models(Ray theory, Parabolic equation, Normal-mode, Wavenumber integration). However, If these models are used for multiple frequency signal analysis, they are inaccurate to calculate result of analysis effectiveness and restricted for signal processing and analysis. In this paper, to overcome this problem, we propose simple/multiple frequency signal analysis model of the Pseudospectral Time-Domain Method synthetic environment UAC applied to underwater environment noise model as like as realistic underwater environment. In order to confirm the validation of the model, we performed the 9 scenarios simulation(4 scenarios of single frequency signal, 4 scenarios of multiple frequency signal, 1 scenario of single/multiple frequency signal like submarine radiated noise) for validation and confirmed the validation of this model through the simulation model.

• Journal of the Korean Society for Railway
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• v.5 no.4
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• pp.253-259
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• 2002

This paper presents the first simulation model using EMTDC program to analyze the electrified train voltage distribution characteristics in ac auto-transformer fed railroads. In general, all of the electrified train supply system has the characteristics that the train supply line is a naturally non-symmetrical and unbalanced system. Also, it is needed to model the Scott transformer which invert the balanced 3-phase quantity into 2-phase. Therefore, the general simulation methodology using previous simplified equivalent circuit or RMS based program can't obtain the accurate results to reflect the real-time operation because these methodology is basically assumed on completely 3-phase balanced system. To overcome these defects, in this paper, the EMTDC simulation model to analysis the completely electrified railroad system with Scott transformer and AC auto-transformer is presented. Also, the correctness of EMTDC modeling is confirmed by the old basic concepts and we think that this EMTDC model has the future powerful capability for application of railroad system analysis.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1874-1880
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• 2011

In this paper, sensitivity analysis of the pantograph for the high-speed Train was conducted using finite element analysis method. Dynamic interaction of catenary-pantograph model was simulated by using a commercial finite element analysis software, SAMCEF. Pantograph was assumed to be three degree of freedom mass-spring-damper model and the pre-sag of the contact and messenger wire was implemented due to gravity. The span data of the actual high-speed line and specification of pantograph for high-speed train was applied in the analysis model, respectively. The reliability of the simulation model is verified by comparing the contact force results of simulation and test. Through the simulation, mean contact force and its deviation was evaluated and then sensitivity of the pantograph was analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.229-232
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• 2005

More than effectively judging the existence of voids behind concrete tunnel linings or under concrete pavements, this research aims to develop the analysis algorithm of radar capable of estimation of the shape of specific voids. To detect or estimate void shapes in non-reinforced concrete, the simulation analysis model of transmission and reflection wave of electromagnetic radar is used. This radar simulation model is carried out with various void shapes. As the results, a proposed method in this study has a possibility of detecting or estimating void shapes with good accuracy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.509-510
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• 2006

Simulation of micro electrical discharge machining (micro-EDM) process using finite element analysis is proposed. Multiphysics model which has three steps; heat transfer analysis, structural analysis and electric field analysis is developed for simulation. Machined surface for successive five discharges is simulated using developed multiphysics model. Machined surface roughness was simulated under two discharge conditions and the simulated results are compared with actual machined surfaces. From the comparison it is demonstrated that the model can accurately predict the machined surface with the error less than $0.5{\mu}m$.

• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.651-660
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• 2009

Detailed flow analysis in river is essential to increase the accuracy of water quality simulation since flow variation depends on many factors such as cross sections, channel slopes, and bed materials. In the QUAL2E stream water quality simulation model, the hydraulic coefficients are assigned to the reach that is collection of computational element using the hydraulic coefficient. This study developed a module that can incorporate the results of non-uniform flow analysis and assign such information to each individual element. Model application focused on the upstream of the Hoengseong reservoir including the reservoir where significant flow change is expected. Comparing with original QUAL2E model the developed module improved the result of water quality simulation without considering the relation of flow velocity and flow depth in terms of flow rates.

• Journal of Ocean Engineering and Technology
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• v.34 no.5
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• pp.316-324
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• 2020

This paper presents comparative studies of reliability analysis and meta-modeling using the sampling method of Monte Carlo simulation for the structure design of an automatic ocean salt collector (AOSC). The thickness sizing variables of structure members are considered as random variables. Probabilistic performance functions are selected from strength performances evaluated via the finite element analysis of an AOSC. The sampling methods used in the comparative studies are simple random sampling and Sobol sequences with varied numbers of sampling. Approximation methods such as the Kriging model is applied to the meta-model generation. Reliability performances such as the probability failure and distribution are compared based on the variation of the sampling method of Monte Carlo simulation. The meta-modeling accuracy is evaluated for the Kriging model generated from the Monte Carlo simulation and Sobol sequence results. It is discovered that the Sobol sequence method is applicable to not only to the reliability analysis for the structural design of marine equipment such as the AOSC, but also to Kriging meta-modeling owing to its high numerical efficiency.