• Nuclear Engineering and Technology
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• v.52 no.4
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• pp.708-720
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• 2020

Core-wide temperature distribution in sodium-cooled fast reactor plays a key role in its decay heat removal process, however the prediction for temperature distribution is quite complex due to the conjugate heat transfer between the assembly flow and the inter-wrapper flow. Hybrid medium model has been proposed for conjugate heat transfer modeling in the core. The core is modeled with a Realistic modeled inter-wrapper flow and hybrid medium modeled assembly flow. To validate present model, simulations for a three-assembly model were performed with Realistic modeling, traditional porous medium model and hybrid medium model, respectively. The influences of Uniform/Non-Uniform power distribution among assemblies and the Peclet number within the assembly flow have been considered. Compared to traditional porous medium model, present model shows a better agreement with in Realistic modeling prediction of the temperature distribution and the radial heat transfer between the inter-wrapper flow and the assembly flow.

• Journal of Sensor Science and Technology
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• v.16 no.3
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• pp.165-173
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• 2007

A differential floating mass transducer has been developed in Korea for fully implantable middle ear hearing devices (F-IMEHDs). In particular, the performance of a differential floating mass transducer (DFMT) is very important among the parts of the F-IMEHDs because the mechanical vibration generated by DFMT is delivered to the inner ear directly. In this paper, the electrical model is proposed to analyze the DFMT vibration characteristic using the mechanical model of the DFMT. The electrical model enables the simple analysis of DFMT vibration characteristics using a computer program. The proposed electrical model is simulated through PSpice as changing the values of passive elements in the electrical model. To verify the proposed model, the DFMT has been implemented on the basis of the simulated results and the experiment for vibration measurement has been carried out. Through the comparison, it is verified that the proposed model is useful to analyze the vibration characteristics of the DFMT.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4244-4252
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• 2022

The accuracy of Monte Carlo (MC) simulations in estimating the computed tomography radiation dose is highly dependent on the accuracy of CT scanner model. A system was developed to observe the 3D model intuitively and to calculate the X-ray energy spectrum and the bowtie (BT) filter model more accurately in Monte Carlo N-particle (MCNP). Labview's built-in Open Graphics Library (OpenGL) was used to display basic surfaces, and constructive solid geometry (CSG) method was used to realize Boolean operations. The energy spectrum was calculated by simulating the process of electronic shooting and the BT filter model was accurately modeled based on the calculated shape curve. Physical data from a study was used as an example to illustrate the accuracy of the constructed model. RMSE between the simulation and the measurement results were 0.97% and 0.74% for two filters of different shapes. It can be seen from the comparison results that to obtain an accurate CT scanner model, physical measurements should be taken as the standard. The energy spectrum library should be established based on Monte Carlo simulations with modifiable input files. It is necessary to use the three-segment splicing modeling method to construct the bowtie filter model.

• The Journal of Sustainable Design and Educational Environment Research
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• v.12 no.2
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• pp.19-30
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• 2013

Low birthrate is causing a reduction in the number of students at kindergartens, elementary schools, middle schools and high schools nationwide and yet, school safety accidents are on a constant rise, which was reported to be 237 accidents a day on average in 2011. Such phenomenon is proving how the school safety policy is not doing what it was supposed to do. In order to decrease the school safety accidents, first, causes of the accidents should be analyzed and then, prevention measures should be designed. For that reason, the study looked into the present condition of the school safety accidents and safety accident theories and based on the results, "School Safety Accident Analysis Matrix Model" was proposed. With a matrix method of the accident types (17 of them) and hazard factors (9 of them) applied, the concerned model analyzed a total of 153 accident causes. In consideration of the results from the analysis, the study suggested that the education authority should open a safety organization and design a school safety policy that would systematically deal with safety education, prevention measures practice, accident investigation and analysis, and countermeasures practice as well.

• Korean Journal of Social Welfare
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• v.66 no.2
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• pp.75-99
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• 2014

The purpose of this study is to examine mediation role of parental attachment, school bonding and delinquent peers in effects of child abuse experience on offending school violence among middle school students. The survey was conducted for boys and girls enrolled in 50 middle schools located in Seoul and Kyung-ki province from October 15 to November 25 in 2012 and total 1,563 were used for final analysis. PASW 18.0, AMOS 18.0 and Mplus were used for statistical analysis. Major findings of this study are as follows. Child abuse experience is analyzed as effecting directly to offending in school violence but also having indirect effecting through mediation process with parental attachment, school bonding and delinquent peers from the analysis of structural equation model. Another finding indicates that multiple indirect effects of parental attachment, school bonding, delinquent peers through Mplus nonlinear analysis, pathways including mediator of parental attachment, school bonding and delinquent peers are verified as statistically significance. Below is discussed for practical and policy implications to prevent school violence in middle school based on this study.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.491-500
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• 2016

This paper presents a highly efficient aeroelastic optimization method based on a surrogate model; the model is verified by considering the case of a high-aspect-ratio composite wing. Optimization frameworks using the Kriging model and genetic algorithm (GA), the Kriging model and improved particle swarm optimization (IPSO), and the back propagation neural network model (BP) and IPSO are presented. The feasibility of the method is verified, as the model can improve the optimization efficiency while also satisfying the engineering requirements. Moreover, the effects of the number of design variables and number of constraints on the optimization efficiency and objective function are analysed in detail. The accuracy of two surrogate models in aeroelastic optimization is also compared. The Kriging model is constructed more conveniently, and its predictive accuracy of the aeroelastic responses also satisfies the engineering requirements. According to the case of a high-aspect-ratio composite wing, the GA is better at global optimization.

• Transactions on Electrical and Electronic Materials
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• v.18 no.5
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• pp.237-245
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• 2017

A novel battery model based on the manufacturer datasheet is proposed. According to this model, not only the steady state but also the dynamic charging performance of the Li-ion battery can be analyzed and evaluated. The major advantage of our model is that all the parameters can be directly obtained from the datasheet and no additional experiments are required. Moreover, the transition between charge and discharge stages was analyzed based on our model, and a novel Simulink module was built to predict the energy consumption of a battery-powered system. Experiments were carried out to verify the model accuracy. Although the new model was developed for the Li-ion battery, it is expected to be applicable to other batteries.

• Computers and Concrete
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• v.1 no.2
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• pp.151-168
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• 2004

A two-dimensional nonlinear finite element model is developed to simulate time-dependent cracking of reinforced concrete members under service loads. To predict localized cracking, the crack band model is employed to model individual crack opening. In conjunction with the crack band model, a bond-interface element is used to model the slip between concrete and reinforcing steel permitting large slip displacements between the concrete element nodes and the steel truss element nodes at crack openings. The time-dependent effects of concrete creep and shrinkage are incorporated into the smeared crack model as inelastic pre-strains in an iterative solution procedure. Two test examples are shown to verify the finite element model with good agreement between the model and the observed test results.

• Journal of Internet Computing and Services
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• v.19 no.6
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• pp.125-132
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• 2018

In this paper, we design a programming education model that uses emotional intelligence and apply the model to programming education in elementary school. In our previous work, we found that there is a meaningful correlation between emotional intelligence and programming ability. In this paper, as a follow-up study, we design a programming education model based on a storytelling model and emotional intelligence. In order to test the performance of the proposed model, we applied our proposed model to the 5th grade elementary school students who have no programming experience. Based on extensive survey work and statistical analysis, we found that the experimental group by the programming education using the emotional intelligence got a statistically significant higher achievement than the comparative group by the traditional programming education. We hope that our model will be helpful in programming education in schools.

• Structural Engineering and Mechanics
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• v.87 no.6
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• pp.601-614
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• 2023

In this study, the uniaxial ratcheting effect of Z2CND18.12N austenitic stainless steel at room and elevated temperatures is firstly simulated based on the Ahmadzadeh-Varvani hardening rule (A-V model), which is embedded into the finite element software ABAQUS by writing the user material subroutine UMAT. The results show that the predicted results of A-V model are lower than the experimental data, and the A-V model is difficult to control ratcheting strain rate. In order to improve the predictive ability of the A-V model, the parameter γ2 of the A-V model is modified using the isotropic hardening criterion, and the extended A-V model is proposed. Comparing the predicted results of the above two models with the experimental data, it is shown that the prediction results of the extended A-V model are in good agreement with the experimental data.