• Journal of Convergence for Information Technology
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• v.7 no.5
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• pp.83-88
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• 2017

This paper describes the azimuth accuracy test of phase comparison direction finding method using F-16 fighter scale-down model. When the antennas are placed on the bottom of a fighter, reflection signals caused by an aircraft structure arises and an azimuth error occurs. In this research, the F-16 fighter scale-down model was made to 5:1, and five antennas were placed on the bottom of the model, then the radio waves of emitters were received by the antennas in the $0-360^{\circ}$ azimuth angles. The accuracy test was performed by numerically analyzing the phases of the radio waves received by the five antennas. The azimuth error of the phase comparison direction finding with scale-down model was measured to be less than $0.5^{\circ}$ when the signal noise ratio was larger then 0dB, and it could be very useful for the design of the phase comparison direction finding method of the fighter.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.281-285
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• 2018

The purpose of this research is to make a Flipped-MOOC model which can be applied and practiced in the college course after analyzing the characteristics and cases of MOOC and Flipped learning. For this, this study implemented the following tasks. First, this study analyzed the management and class types of MOOC and flipped learning through literature research. Secondly, flipped learning was applied in the course for a semester and the strong point and weak point of the course was analyzed and the alternative was suggested. Thirdly, the core ideas and strategies of Flipped-MOOC model was deducted for enhancing the participation and interaction of the students in the course which uses the MOOC content and applies flipped learning, and the instructional strategies and direction for the effective management in the real educational field was suggested. As a result, Flipped-MOOC model is expected to contribute for the educational revolution, change and quality improvement, and it is expected that Flipped-MOOC model might contribute to the lifelong education and educational competitiveness.

• Journal of Convergence for Information Technology
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• v.9 no.3
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• pp.36-43
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• 2019

The purpose of this study is the preliminary inequality experiment study of control group to confirm the effects of convergence education by jigsaw model and flipped learning in nursing students. The subjects of this study were 81 students who participated in Integrated Practice II of the 3rd grade of Nursing Science in J area and data were collected using the questionnaire before and after the convergence education. As a result of the study, it was found that convergence education by jigsaw model and flipped learning was significant in learning satisfaction(t=-3.783, p=.001). Therefore, convergence education by jigsaw model and flipped learning as a teaching and learning method is expected to improve the learning satisfaction and maximize the learning outcome, so this study is meaningful as the basic data itself. Based on these results, it is necessary to develop and apply the teaching - learning program that combines jigsaw model with flipped learning.

• Journal of Convergence for Information Technology
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• v.10 no.12
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• pp.236-244
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• 2020

In this research a suspended solid transport experiment was conducted in the river experiment center to find the characteristics and dispersion of the material. Modeling by the particle dispersion model was also executed to reproduce the suspended solid transport. The suspended solid was consisted of a mixture of silica and water using a mixing equipment, which was then introduced into a real-scale flume and measured with the laser-diffraction based particle size analyzer(LISST) to find the concentration of the material. The comparison between the measured suspended solid concentration using drone images and particle size analyzers, with the model showed a good match overall, which proved the applicability of the model. Along with finding the model applicability, the research showed the potential for suspended solid estimation in high flow situations with high rainfall.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.321-325
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• 2020

Purpose: This study is to evaluate the accuracy of gypsum replica models made from various gypsum products. Methods: One main model was made of stainless steel by CNC milling process. Molds were formed from the main model, and the gypsum replica models were made using 8 types of type IV gypsum, 10 pieces each. The main model was digitized by a contact scanner (Incise; Renishaw) and the gypsum replicas were digitized by an optical scanner (E4; 3Shape A/S). The difference between the main model and the gypsum replicas were measured by inspection software (3D Systems). One-way ANOVA was performed to evaluate the statistical significance of differences between groups. In addition, the independent sample T test was performed to determine the difference between the conventional and scannable stone group (n=10, α=0.05). Results: The root mean square of the stone models were 7.24 ㎛ to 10.78 ㎛, and statistical significance was found between the two groups (SR, FR) and the other 6 groups (IS, SG, CA, CS, ER, EBG) (p<0.05). The accuracy of the gypsum replicas was 9.04 ㎛ and 7.62 ㎛ in the conventional and scannable stone group, respectively. There was statistical significance between the two groups (p<0.01). Conclusion: In the limited results of this study, the product with low setting expansion and the scannable showed high accuracy. Therefore, in order to obtain a stable and accurate scan model, it is more effective in terms of accuracy to use a scannable stone with a low setting expansion.

• Journal of Convergence for Information Technology
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• v.11 no.3
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• pp.125-131
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• 2021

The problem of determining the maintenance point which minimizes the process-related total cost is called the 'process mean shift problem'. By expanding and integrating the existing maintenance models that have been partially progressed, we present a expanded and integrated maintenance model which reflects the production site where various situations occur. To implement this, we set both the upper and lower limits of the product specification, and adopted the quality loss function for conforming items. Also, we set the process variance of the wear level as a function rather than a constant. In this study, we developed two general functions to the wear level. One is about the production volume and the other is maintenance cost. As a result, this study is expected to be a maintenance model that can be applied to various processes. In the future, this study can be developed as a profit maximization model by adding profit items from product sales, and expansion to a maintenance model that introduces failure to the model of this study can be considered.

• Progress in Medical Physics
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• v.21 no.1
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• pp.93-98
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• 2010

The aim of this work was to establish the methodology for event positioning by measuring depth of interaction (DOI) information and to evaluate the system sensitivity and spatial resolution of the new detector for I-125 and Tc-99m imaging. For this purpose, a Monte Carlo simulation tool, DETECT2000 and GATE were used to model the energy deposition and light distribution in the detector and to validate this approach. Our proposed detector module consists of a monolithic CsI(Tl) crystal with dimensions of $50.0{\times}50.0{\times}3.0\;mm^3$. The results of simulation demonstrated that the resolution is less than 1.5 mm for both I-125 and Tc-99m. The main advantage of the proposed detector module is that by using 3 mm thick CsI(Tl) with maximum-likelihood position-estimation (MLPE) method, high resolution I-125 imaging and high sensitivity Tc-99m imaging are possible. In this paper, we proved that our new detector to be a reliable design as a detector for a multi-energy SPECT.

• Journal of Radiation Protection and Research
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• v.45 no.3
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• pp.101-107
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• 2020

Background: An important lesson learned from the Fukushima accident is that the transition to the mid- and long-term phases from the emergency-response phase requires less than a year, which is not very long. It is necessary to know how much radioactive material has been deposited in an urban area to establish mid- and long-term countermeasures after a radioactive accident. Therefore, an urban deposition model that can indicate the site-specific characteristics must be developed. Materials and Methods: In this study, the generalized urban deposition velocity and the subsequent variation in radionuclide contamination were estimated based on the characteristics of the Korean urban environment. Furthermore, the application of the obtained generalized deposition velocity in a hypothetical scenario was investigated. Results and Discussion: The generalized deposition velocities of ¹³⁷Cs, ¹⁰⁶Ru, and ¹³¹I for each residence type were obtained using three-dimensional (3D) modeling. For all residence types, the deposition velocities of ¹³¹I are greater than those of ¹⁰⁶Ru and ¹³⁷Cs. In addition, we calculated the generalized deposition velocities for each residential types. Iodine was the most deposited nuclide during initial deposition. However, the concentration of iodine in urban environment drastically decreases owing to its relatively shorter half-life than ¹⁰⁶Ru and ¹³⁷Cs. Furthermore, the amount of radioactive material deposited in nonresidential areas, especially in parks and schools, is more than that deposited in residential areas. Conclusion: In this study, the generalized urban deposition velocities and the subsequent deposition changes were estimated for the Korean urban environment. The 3D modeling was performed for each type of urban residential area, and the average deposition velocity was obtained and applied to a hypothetical accident. Based on the estimated deposition velocities, the decision-making systems can be improved for responding to radioactive contamination in urban areas. Furthermore, this study can be useful to predict the radiological dose in case of large-scale urban contamination and can support decision-making for long-term measurement after nuclear accident.

• Tuberculosis and Respiratory Diseases
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• v.39 no.4
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• pp.325-333
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• 1992

Background and Methods: To study the effects of corticosteroid (CS) on the parquat (PQ) induced lung injury, serial cellular analyses of bronchoalveolar lavage (BAL) fluid were done with simultaneous histopathologic examination after intraperitoneal injection of PQ on the rats. The sacrificed animals were divided into three groups; control group, PQ group received intraperitoneal injection of 20 mg/kg of PQ, and CS group received daily injection of Methylprednisolone sodium succinate (20 mg/kg) in addition to PQ. Results: 1) Cellular analyses of BAL fluid: The total cell count in the BAL fluid were increased gradually from 6 hours after PQ administration (p<0.05), and was decreased at 3 days after (p<0.05). These changes were mainly due to the effects of PQ on the neutrophil influx (p<0.05). But, the number of macrophage and the percentage of lymphocyte in total cells showed little changes. The CS administration showed the suppression of neutrophil influx in the BAL fluid (p<0.05), but could not show any significant effect on the number of macrophage and lymphocyte. 2) Histopathologic examination: In the PQ group, inflammatory changes especially with prominant neutrophil infiltration were gradually progressed over time. Those changes were found in both alveolar space and interstitium with resultant alveolar structural changes, but subsided from 3 days after. CS suppressed inflammatory changes in the alvolar space and interstitium, especially with decreased infiltration of neutrophil. Conclusion: CS suppressed neutrophil infiltration in the acute lung injury induced by PQ, those findings were ascertained by serial cellular analyses of BAL fluid and histopathologic examination.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.172-178
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• 2014

This paper presents a new model of the Miller effect. The new Miller effect model is obtained from the accurate AC gain which includes the effect of the output capacitance of the common-source (CS) amplifier. The new Miller effect model consists of the series connection of a capacitance and a parallel RC circuit, one at the input and the other at the output. The frequency response obtained by the new Miller effect model is equal to that obtained from the original circuit. Even though the new model is complicated, the 3-dB frequency can be easily estimated by using the open-circuit time constants method without the node analysis.