• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.57-66
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• 2016

Harmonized World Soil Database (HWSD) including the global soil information has been implemented to the runoff analysis in many watersheds of the world. However, its accuracy can be a critical issue in the modeling because of the limitation the low resolution reflecting the physical properties of soil in a watershed. Accordingly, this study attempted to assess the effect of HWSD in modeling by comparing parameters of the rainfall-runoff model using HWSD with the detailed soil map. For this, Grid based Rainfall-runoff Model (GRM) was employed in the Hyangseok watershed. The results showed that both of two soil maps in the rainfall-runoff model are able to well capture the observed runoff. However, compared with the detailed soil map, HWSD produced more uncertainty in the GRM parameters related to soil depth and hydraulic conductivity during the calibrations than the detailed soil map. Therefore, the uncertainty from the limited information on soil texture in HWSD should be considered for better calibration of a rainfall-runoff model.

• Transactions of Materials Processing
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• v.23 no.4
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• pp.199-205
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• 2014

The current study examines the effect of the analytical parameter values on the theoretical forming limit diagram (FLD) based on the Marciniak-Kuczynski model (M-K model). Tensile tests were performed to obtain stress-strain curves and determine the anisotropic properties in the rolling, transverse and diagonal direction of SPCC sheet materials. The experimental forming limit curve for SPCC sheet material was obtained by limiting dome stretching tests. To predict the theoretical FLD based on the M-K model, the Hosford 79 yield function was employed. The effects of three analytical parameters - the exponent of the yield function, the initial imperfection parameter and the fracture criterion parameter - on the M-K model, were examined and the results of the theoretical FLD were compared to the experimentally measured FLD. It was found that the various analytical parameters should be carefully considered to reasonably predict the theoretical FLD. The comparison of the acceptable forming limit area between the theoretical and experimental FLD is used to compare the two diagrams.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.73.3-73.3
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• 2019

The AGN unification model suggested the presence of obscuring material, a dusty torus, to explain the various types of AGN. IR SED model fitting is a crucial tool to probe the structure and properties of the dusty torus. We use a sample of 16 local quasi-stellar objects in Martinez-Paredes et al. (2017) with obtained NIR and MIR high-angular resolution (~0.3") imaging data from EMIR, CIRCE and CanariCam on the 10.4-m Gran Telescopio CANARIAS (GTC) while 4 objects have NIR high-angular resolution photometry from NICMOS/HST from the literature. The unresolved NIR emission from the NIR image analysis and low-resolution Spitzer/IRS spectra are used to construct NIR-MIR SEDs covering a larger spectral range. We investigate the sensitivity of the geometrical (e.g. viewing angle) and physical parameters (e.g. optical depth) of the clumpy dusty torus model of Nenkova et al. and the clumpy disk+outflow model of Hoenig et al. We aim to investigate the minimal dataset needed to well constrain the parameters of the models and derive the properties of the dusty torus. These results will allow us to plan future observations for a larger sample of high luminosity AGNs with the James Webb Space Telescope and the Giant Magellan Telescope.

• Journal of the Chungcheong Mathematical Society
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• v.26 no.4
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• pp.787-791
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• 2013

In this paper we present one factor model of commodity prices with a single jump regime-switching process. And we derive an analytic formula for pricing futures contracts when the parameters of commoditiy process have governed by a Markov regime-switching process.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.655-664
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• 2009

This paper, Part 1, describes the effective dual-input PSS parameter design procedure for the IEEE Type PSS2A against the Dangjin 612 MVA thermal plant's EX2000 excitation system. The suggested tuning technique used the model-based PSS tuning method and consisted of three steps: 1) generation system modeling; 2) determination of PSS2A model parameters using linear, time-domain transient and 3-phase simultaneous analyses, and 3) field testing and verification, which are described in Part 2. The effective PSS2A model parameters of EX2000 system in the Dangjin T/P #4 were designed according to the suggested procedure, and verified by using three analyses.

• Transactions of Materials Processing
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• v.19 no.4
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• pp.217-223
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• 2010

The objective of this study is to propose the FE model for mechanical clinched joint using cohesive zone model to analyze its failure behavior under impact loading. Cohesive zone model (CZM) is two-parameter failure criteria approach, which could describe the failure behavior of joint using critical stress and fracture toughness. In this study, the relationship between failure behavior of mechanical clinched joint and fracture parameters is investigated by FE analysis with CZM. Using this relationship, the critical stress and fracture toughness for tensile and shear mode are determined by H-type tensile test and lap shear test, which were made of 5052 aluminum alloy. The fracture parameters were applied to the tophat impact test to evaluate the crashworthiness. Compared penetration depth and energy absorption at the point where 50% of total displacement in result of FE analysis and experiment test for impact test, those has shown similar crashworthiness.

• The Journal of Korea Robotics Society
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• v.18 no.4
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• pp.481-486
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• 2023

The purpose of this study is to optimize parameters of a contact model to obtain similar ground contact force of human walking. Dynamic walking simulation considering ground contact is performed to determine load specifications when developing walking assist robots. Large contact forces that are not observed in actual experimental data occur during the simulation at the initial contact (e.g., heel contact). The large contact force generates unrealistic large joint torques. A lower exoskeleton robot with no ankles is developed with the Matlab simscape and the nonlinear hyper volumetric contact model is applied. Parameters of the nonlinear hyper volumetric model were optimized using actual walking contact force data. As a result of optimization, it was possible to obtain a contact force pattern similar to actual walking by removing the large contact force generated during initial contact.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1085-1090
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• 2002

Genetic parameters for birth weights (BWT), calving ease scores observed from calves born by heifers (CEH), and calving ease scores observed from calves born by cows (CEC) were estimated using Bayesian methodology with Gibbs sampling in different threshold animal models. Data consisted of 77,458 records for calving ease scores and birth weights in Gelbvieh cattle. Gibbs samplers were used to obtain the parameters of interest for the categorical traits in two univariate threshold animal models, a bivariate threshold animal model, and a three-trait linear-threshold animal model. Samples of heritabilities and genetic correlations were calculated from the posterior means of dispersion parameters. In a univariate threshold animal model with CEH (model 1), the posterior means of heritabilities for calving ease was 0.35 for direct genetic effects and 0.18 for maternal genetic effects. In the other univariate threshold model with CEC (model 2), the posterior means of heritabilities of CEC was 0.28 for direct genetic effects and 0.18 for maternal genetic effects. In a bivariate threshold model with CEH and CEC (model 3), heritability estimates were similar to those in unvariate threshold models. In this model, genetic correlation between heifer calving ease and cow calving ease was 0.89 and 0.87 for direct genetic effect and maternal genetic effects, respectively. In a three-trait animal model, which contained two categorical traits (CEH and CEC) and one continuous trait (BWT) (model 4), heritability estimates of CEH and CEC for direct (maternal) genetic effects were 0.40 (0.23) and 0.23 (0.13), respectively. In this model, genetic correlation estimates between CEH and CEC were 0.89 and 0.66 for direct genetic effects and maternal effects, respectively. These estimates were greater than estimates between BWT and CEH (0.82 and 0.34) or BWT and CEC (0.85 and 0.26). This result indicates that CEH and CEC should be high correlated rather than estimates between calving ease and birth weight. Genetic correlation estimates between direct genetic effects and maternal effects were -0.29, -0.31 and 0.15 for BWT, CEH and CEC, respectively. Correlation for permanent environmental effects between BWT and CEC was -0.83 in model 4. This study can provide genetic evaluation for calving ease with other continuous traits jointly with assuming that calving ease from first calving was a same trait to calving ease from later parities calving. Further researches for reliability of dispersion parameters would be needed even if the more correlated traits would be concerned in the model, the higher reliability could be obtained, especially on threshold model with property that categorical traits have little information.

• Structural Monitoring and Maintenance
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• v.4 no.4
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• pp.365-379
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• 2017

This paper presents a comparison of the black-box and the physics based derived gray-box models for subspace identification for structures subjected to support-excitation. The study compares the damage detection capabilities of both these methods for linear time invariant (LTI) systems as well as linear time-varying (LTV) systems by extending the gray-box model for time-varying systems using short-time windows. The numerically simulated IASC-ASCE Phase-I benchmark building has been used to compare the two methods for different damage scenarios. The efficacy of the two methods for the identification of stiffness parameters has been studied in the presence of different levels of sensor noise to simulate on-field conditions. The proposed extension of the gray-box model for LTV systems has been shown to outperform the black-box model in capturing the variation in stiffness parameters for the benchmark building.

• Computers and Concrete
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• v.3 no.4
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• pp.197-212
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• 2006

Modeling of physically non-linear behavior becomes more and more important for the analysis of SFRC structures in practical applications. From this point of view we will present an effective, three-dimensional constitutive model for SFRC, that is also easy to implement in commercial finite element programs. Additionally, the finite element analysis should only require standard material parameters which can be gained easily from conventional experiments or which are specified in appropriate building codes. Another important point is attaining the material parameters from experimental data. The procedures to determine the material parameters proposed in appropriate codes seem to be only approximations and are unsuitable for precise structural analysis. Therefore a finite element analysis of the test itself is used to get the material parameters. This process is also denoted as inverse analysis. The efficiency of the proposed constitutive model is demonstrated on the basis of numerical examples and their comparison to experimental results. In the framework of material parameter identification the idea of a new, indirect tension testing procedure, the "Modified Tension Test", is adopted and extended to an easy-to-carry-out tension test for steel fiber reinforced concrete specimens.