• Journal of Digital Convergence
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• v.13 no.10
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• pp.121-133
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• 2015

This tutorial presents an approach to perform the covariance based structural equation modeling using the R. For this purpose, the tutorial defines the criteria for the covariance based structural equation modeling by reviewing previous studies, and shows how to analyze the research model with an example using the "lavaan" which is the R package supporting the covariance based structural equation modeling. In this tutorial, a covariance-based structural equation modeling technique using the R and the R scripts targeting the example model were proposed as the results. This tutorial will be useful to start the study of the covariance based structural equation modeling for the researchers who first encounter the covariance based structural equation modeling and will provide the knowledge base for in-depth analysis through the covariance based structural equation modeling technique using R which is the integrated statistical software operating environment for the researchers familiar with the covariance based structural equation modeling.

• Journal of the military operations research society of Korea
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• v.32 no.2
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• pp.56-77
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• 2006

This paper suggests more improved war-game modeling methodology for close combat attrition modeling. Military operation analysts have been using equation-based modeling techniques such as Lanchester-type differential equation modeling, for combat attrition evaluation. This modeling methodology is easy to analyze and evaluate the war-game simulation results but has several limitations to simulate the dynamic combat environment. To overcome these shortcomings, we propose the agent-based modeling methodology. This methodology is modeling close combat based in attrition behaviors instead of attrition coefficients. The simulation analysis & evaluation is executed for these two kinds of modeling methodology on the similar close combat situation.

• East Asian mathematical journal
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• v.34 no.5
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• pp.661-681
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• 2018

In this paper, we discuss a reduced-order modeling for the Benjamin-Bona-Mahony-Burgers (BBMB) equation and its application to a distributed feedback control problem through the centroidal Voronoi tessellation (CVT). Spatial distcritization to the BBMB equation is based on the finite element method (FEM) using B-spline functions. To determine the basis elements for the approximating subspaces, we elucidate the CVT approaches to reduced-order bases with snapshots. For the purpose of comparison, a brief review of the proper orthogonal decomposition (POD) is provided and some numerical experiments implemented including full-order approximation, CVT based model, and POD based model. In the end, we apply CVT reduced-order modeling technique to a feedback control problem for the BBMB equation.

• Knowledge Management Research
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• v.20 no.2
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• pp.1-24
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• 2019

This tutorial introduces procedures and methods for performing structural equation modeling using R. To do this, we present advanced analysis methods based on structural equation model such as mediation effect analysis, moderation effect analysis, moderated mediation effect analysis, and multiple-group analysis with R program code using R lavaan package that supports structural equation modeling. R is flexible and scalable, unlike traditional commercial statistical packages. Therefore, new analytical techniques are likely to be implemented ahead of any other statistical package. From this point of view, R will be a very appropriate choice for applying new analytical techniques or advanced techniques that researchers need. Considering that various studies in the social sciences are applying structural equations modeling techniques and increasing interest in open source R, this tutorial is expected to be useful for researchers who are looking for alternatives to existing commercial statistical packages.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.19 no.2
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• pp.123-135
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• 2015

In this paper, a reduced-order modeling(ROM) of Burgers equations is studied based on pseudo-spectral collocation method. A ROM basis is obtained by the proper orthogonal decomposition(POD). Crank-Nicolson scheme is applied in time discretization and the pseudo-spectral element collocation method is adopted to solve linearlized equation based on the Newton method in spatial discretization. We deliver POD-based algorithm and present some numerical experiments to show the efficiency of our proposed method.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.7
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• pp.862-871
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• 2003

In this paper, we addressed a modeling for the magnetic levitation stage. This planar magnetic levitator employs four permanent magnet liner motors. Each motor generates vertical force for suspension against gravity, as well as horizontal force for propulsion. Therefore. this stage can generate six degrees of freedom motion by the combination of forces. We derived a mechanical dynamics equation using Lagrangian method and electromechanical dynamics equation by using Co-energy method. Based on the derived dynamics, we can analyze the stage motion that is subject to the input currents and forces.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.9
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• pp.64-75
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• 1993

This paper proposes a recovering technique of the elevation map by stereo modeling of the aerial image sequence which is transformed based on the aircraft situation. The area-based stereo matching method is simulated and the various parameters are experimentally chosen. In a depth extraction step, the depth is determined by solving the vector equation. The equation is suitable for stereo modeling of aerial images which do not satisfy the epipolar constraint. Also, the performance of the conventional feature-based matching scheme is compared. Finally, techniques analyzing the accuracy of the recovered elevation map (REM) are described. The analysis includes the error estimation for both height and contour lines, where the accuracy is based on the measurements of deviations from the estimates obtained manually. The experimental results show the efficiency of the proposed technique.

• Journal of Information Display
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• v.10 no.3
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• pp.101-106
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• 2009

In this study, a physical OLED analog behavior model for SPICE simulation was described using the Verilog-A language. The model was presented through theoretical equations for the J-V characteristics of OLED derived according to the internalcarrier emission equation based on a diffusion model at the Schottky barrier contact, and the mobility equation based on the Pool-Frenkel model. The accuracy of this model was examined by comparing it with the results of the device simulation that was conducted.

• Journal of the Korean Electrochemical Society
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• v.22 no.1
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• pp.43-52
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• 2019

As the application area of lithium secondary batteries becomes wider, performance characterization becomes difficult as well as diverse. To address this issue, battery manufacturers have to evaluate many batteries for a longer period, recruit many researchers and continuously introduce expensive equipment. Simulation techniques based on battery modeling are being introduced to solve such difficulties. Various lithium secondary battery modeling techniques have been reported so far and optimal techniques have been selected and utilized according to their purpose. In this review, the electrochemical modeling based on the Newman model is described in detail. Particularly, we will explain the physical meaning of each equation included in the model; the Butler-Volmer equation, which represents the rate of electrode reaction, the material and charge balance equations for each phase (solid and liquid), and the energy balance. Moreover, simple modeling processes and results based on COMSOL Multiphysics 5.3a will be provided and discussed.

• Journal of Information Technology Services
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• v.10 no.2
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• pp.203-221
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• 2011

The purpose of this study is to investigate the applications of Structural Equation Modeling(SEM) into MIS area in recent years. Two methodologies, Lisrel and PLS, are adopted for the method comparison. A research model, based upon TAM(Technology Acceptance Model) is used for the analysis of the data set of a previous study. The research model includes six research variables that are composed of twenty-eight question items. 272 data are used for data analyses through Lisrel v.8.72 and Visual PLS v.1.04. This study shows the statistical results of Lisrel are the same to those of PLS. The contribution of this study can be suggested as the followings; (1) A theoretical comparison of two methodologies is shown, (2) A statistical analysis is done at a real-situated data set, and (3) Several implications are suggested.