• Explosives and Blasting
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• v.37 no.3
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• pp.1-12
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• 2019

The analysis methods of blast analysis models are classified into direct analysis and indirect analysis, and the latter is divided into semi-empirical and numerical analysis methods. In order to evaluate the applicability of the ELS blast analysis program, which is a program for analyzing the semi-empirical models, this study selected a simplified analytical model and examined the blast load characteristics of free-air burst explosion and surface burst explosion by using AT-Blast, RC-Blast, and Kinney and Graham's empirical equations, which are the semi-empirical analysis programs. As a result of analyzing the explosion pressure for the scaled distance and the incidence angle for the simplified analytical model, an appropriate analysis can be performed when the range of the scaled distance in the free-air burst explosion analysis was 0.3~0.461 and when the range of the scaled distance in the surface burst explosion analysis was 0.378~0.581. In terms of the incidence angle, the results analyzed within $45^{\circ}$ were considered to be appropriate.

• Korean Journal of Remote Sensing
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• v.10 no.2
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• pp.17-35
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• 1994

A semi-empirical model for microwave polarimetric radar backscattering from bare soil surfaces was developed using polarmetric radar measurements and the knowledge based on the theoretical and numerical solutions. The microwave polarimetric backscatter measurements were conducted for bare soil surfaces under a variety of roughness and moisture conditions at L-, C-, and X-band frequencies at incidence angles ranging from 10` to 70`. Since the accrate target parameters as well as the radar parameters are necessary for radar scattering modeling, a complete and accurate set of ground truth data were also collected using a laser profile meter and dielectric probes for each surface condition, from which accurate measurements were made of the rms height, correlation length, and dielectric constant. At first, the angular and spectral dependencies of the measured radar backscatter for a wide range of roughnesses and moisture conditions are examined. Then, the measured scattering behavior was tested using theoretical and numerical solutions. Based on the experimental observations and the theoretical and numerical solutions, a semi-empirical model was developed for backscattering coeffients in terms of the surface roughness parameters and the relative dielectric constant of the soil surface. The model was found to yield very good agreement with the backscattering measurements of this study as well as with independent measurements.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.154-157
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• 1999

Microwave polarimetric backscattering from a wet soil surface had been measured using a Ku-band polarimetric scatterometer at the incidence angles ranging from 10$^{\circ}$ to 70$^{\circ}$ Since the accurate target parameters as well as the radar parameters are necessary for radar scattering modeling, a complete and accurate set of ground truth data were also collected, from which accurate measurements were made of the rms height, correlation length, and dielectric constant. The measured polarimetric backscattering coefficients (vv-, hh-, vh-, hv-polarizations) were compared with theoretical models and empirical models. A new semi-empirical model for microwave polarimetric radar backscattering from bare soil surfaces was developed using polarimetric radar measurements and the knowledge based on the theoretical and numerical solutions. The model was found to yield very good agreement with the backscattering measurements of this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.638-643
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• 2005

This study is about a semi-active quarter car simulation method including a MR(magneto-rheological) damper. The MR damper was modeled as Spencer model that can capture nonlinear and hysteretic behavior. The parameters of the Spencer model were extracted from a random excitation test and optimum treatment of the test data. Then, a suspension control algorithm based on Sky-hook theory was applied for the quarter car simulation. Also, an experiment was dong using a quarter car simulator to confirm the simulation results with the Spencer MR damper model

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.9 s.102
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• pp.1016-1022
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• 2005

This study is about a semi-active quarter car simulation method including a MR(magneto-rheological) damper. The MR damper was modeled as Spencer model that can capture nonlinear and hysteretic behavior. The parameters of the Spencer model were extracted from a random excitation test and optimum treatment of the test data. Then, a suspension control algorithm based on Sky-hook theory was applied for the quarter car simulation. Also, an experiment was done using a quarter car simulator to confirm the simulation results with the Spencer MR damper model.

• Steel and Composite Structures
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• v.11 no.4
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• pp.325-340
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• 2011

Based on the experimental data presented in part I of these companion papers, a semi-empirical model is proposed for axial stress-strain curves of reinforced high-strength concrete square columns confined by aramid fiber reinforced polymer (FRP) jackets. Additionally, a three-dimensional finite element model is developed to simulate the mechanical behaviors of the columns. In the finite element model, both material nonlinear and contact nonlinear are taken into account. Moreover, the influence of contact nonlinear (i.e., the end friction on the contact surface between test machines and specimens) is investigated deeply. Predictions from both the semi-empirical model and the finite element model agree with the experimental results, and it is also demonstrated that the friction coefficient of end friction notably affect the properties of columns when it ranges from 0.00 to 0.25.

• International Journal of Air-Conditioning and Refrigeration
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• v.7
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• pp.11-21
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• 1999

The capillary tube and short tube orifice have been widely used as an expansion device in the refrigeration and air-conditioning system. To improve the system performance, expansion devices need to be optimized with the components of a refrigeration system. In the present study, a numerical model for a capillary, which could predict the flow rate and properties along a tube, was developed by assuming homogeneous two-phase flow. A semi-empirical flow model for evaluation of the flow rate through a short tube orifice was also developed by using the experimental data. Finally, the results of the numerical model for a capillary was compared with those of the semi-empirical model for a short tube orifice to identify the dominant flow factors for the expansion devices.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.1
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• pp.118-128
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• 1998

Capillary and short tube orifice have been widely used as an expansion device in refrigeration and air-conditioning system. To improve the system performance, expansion devices need to be optimized with the components of a refrigeration system. In the present study, a numerical model for a capillary, which can predict properties along a tube and flow rate through a tube, was developed by assuming homogeneous two-phase flow, A semi-empirical flow model that can be used to evaluate the flow rate through a short tube orifice was also developed by summarizing the experimental data. Finally, the results of the numerical model for capillaries were compared with those of the semi-empirical model for short tube orifices to verify dominant flow factors for the expansion devices.

• Journal of Korea Foundry Society
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• v.37 no.5
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• pp.157-163
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• 2017

In the present study, the microstructural evolution and deformation behavior of AA 2014 aluminum alloys with different microstructures in a semi-solid state were investigated. For a given alloy, applied load and deformation time, the measured strain was higher at a higher temperature, indicative of a lower solid fraction. When a large proportion of the liquid was present as intragranular droplets, the alloy would not as easily deform because the effective liquid fraction between the solid grains had decreased. Greater deformation was achieved with higher grain boundary misorientations due to the enhanced wetting of the grain boundaries with liquid. A semi-empirical constitutive model is proposed for semi-solid deformation under the conditions in the present study. The mechanism of semi-solid deformation incorporates the initial flow of the liquid in the early stages of deformation, followed by a more gradual increase in the strain due to deformation by grain sliding accompanied by self-diffusion in the solid grains.

• Communications for Statistical Applications and Methods
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• v.30 no.4
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• pp.355-368
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• 2023

This article introduces the R package ELCIC (https://cran.r-project.org/web/packages/ELCIC/index.html), which provides an empirical likelihood-based information criterion (ELCIC) for model selection that includes, but is not limited to, variable selection. The empirical likelihood is a semi-parametric approach to draw statistical inference that does not require distribution assumptions for data generation. Therefore, ELCIC is more robust and versatile in the context of model selection compared to the currently existing information criteria. This paper illustrates several applications of ELCIC, including its use in generalized linear models, generalized estimating equations (GEE) for longitudinal data, and weighted GEE (WGEE) for missing longitudinal data under the mechanisms of missing at random and dropout.