• Journal of Korea Foundry Society
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• v.27 no.1
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• pp.42-47
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• 2007

Vacuum molding process(V-process) has several benefits such as a lower total production cost and a high quality casting comparing to the conventional sand molding. Influence of the gating design on the molten metal flow was investigated in this study. General criteria for the gating design of the castings and commercial codes for the flow and solidification analysis were used to attain the optimized gating design in V-process. Though mold cavity was filled smoothly under the low initial velocity of molten metal, molten metal dashed against the upper part of the mold before the completion of the mold filling with higher initial molten metal velocity and fell soon. This phenomenon may affect collapsing the mold shape, however it is thought that the possibility of burning out of the vinyl by the molten metal is not so high because vinyl is coated with refractory material.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.2
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• pp.51-58
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• 2016

The importance of SW education is being stressed recent days, and the App Inventor is getting attention as a tool of SW education. In this study, I have developed an app Inventor instruction model, which is based on the Design Based Learning and integrated with elements of computational thinking. And I taught the student to apply this model. and then analyzed the app production process and the changes of student. In developing the app, students defined the problem and made a plan to resolve them. And this student had have a sense of accomplishment and self-confidence through practical experience to implement it in their own source code.

• The Korean Journal of Mycology
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• v.26 no.3 s.86
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• pp.396-398
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• 1998

This study was carried out to obtain the basic data for artificial production of Polyporus umbellatus. Among logs consisted of 16 tree species, the log of Stylax japonica inoculated with Polyporus umbellatus not only produced compact sclerotia of $3{\sim}5\;mm$ in their diameters but resulted in the good mycelial density. Also, the sclerotia were observed on 6 different kinds of logs inoculated with Polyporus umbellatus.

• Journal of the Korean Society for Nondestructive Testing
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• v.34 no.6
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• pp.457-466
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• 2014

This paper presents an analytic and numerical simulation of the generation and propagation of pico-second ultrasound with nano-scale wavelength, enabling the production of bulk waves in thin films. An analytic model of laser-matter interaction and elasto-dynamic wave propagation is introduced to calculate the elastic strain pulse in microstructures. The model includes the laser-pulse absorption on the material surface, heat transfer from a photon to the elastic energy of a phonon, and acoustic wave propagation to formulate the governing equations of ultra-short ultrasound. The excitation and propagation of acoustic pulses produced by ultra-short laser pulses are numerically simulated for an aluminum substrate using the finite-difference method and compared with the analytical solution. Furthermore, Fourier analysis was performed to investigate the frequency spectrum of the simulated elastic wave pulse. It is concluded that a pico-second bulk wave with a very high frequency of up to hundreds of gigahertz is successfully generated in metals using a 100-fs laser pulse and that it can be propagated in the direction of thickness for thickness less than 100 nm.

• Journal of Korean language education
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• v.28 no.2
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• pp.1-36
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• 2017

This study investigated the correlation between learners' psychological and social factors and their syntactic complexity of speaking. The study collected samples of Korean spoken production of 61 learners with English, Chinese, Japanese and other L1 backgrounds and applied mini-TOPIK, mini-AMTB, and SASIQ for 70 minutes. The study found that: (i) integrative motivation showed positive correlation with a number of simple complex clauses, but instrumental motivation correlated negatively with a number of adverbial clauses, indicating that high motivation hindered producing highly complex clauses although it triggered producing simple complex clauses, (ii) social contact with L2 native speakers showed positive correlation with general L2 development and a number of simple complex clauses, but revealed negative correlation with double or triple complex clauses, (iii) hours of L2 listening showed very strong positive correlation with producing triple complex clauses and general proficiency, but indicated negative correlation with a number of simple complex clauses. The study reported that high motivation toward Korean learning and active social activities with Korean native speakers helped produce simple complex clauses while hours of listening to Korean helped produce triple complex clauses.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1435-1441
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• 2014

The fire took place in the synthetic heat transfer fluid boiler used in production process of medium density fiberboard. This study investigated pressure distribution of the first, second and third passes and the temperature in the fire burner. The boiler's internal fluid is unsteady due to the out of order inverter. As the operation continues, the flame's flow and speed are unsteady. The synthetic heat transfer fluid leak spouted about 120kg/min in the form of vapor in the early period of the fire. The flame extended to the second and third passes. The highest temperature of the second and third pass is $1059^{\circ}C$ and $1007^{\circ}C$, respectively. The synthetic heat transfer fluid spouted through the cracked part of the fire box in the first pass and accumulated on the turn table. Therefore, it is expected that the temperature of the interior of the fire box is above $1200^{\circ}C$. The temperature of the burner rises to a maximum level several times in a short period. On account of that, several explosions occur in the fire burner. Pressure distribution at steady state in combustion furnace is 2~5mAq and pressure distribution at inverter under fault condition in combustion furnace is 10~-53mAq. The decrement of coil thickness measurement for synthetic heat transfer fluid boiler is 0~5mm.

• Journal of the Semiconductor & Display Technology
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• v.17 no.3
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• pp.10-16
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• 2018

In silicon crystalline PV (Photo Voltaic) industry, PV module or panel electric power is directly related to the companies' profit. Thus, many PV companies have invested and focused on R&D activities to get the higher module power. The main BOM (Bills of Material) on the module consists of PV solar cell, ribbon, EVA (Ethylene-Vinyl Acetate copolymer), glass and back sheet. Based on consistent research efforts on enhancing module power using BOM, there have been increase of around 5 watt per module every year as results. However, there are lack of studies related to enhancing accuracy of measurement. In this study, the enhancing on the metrology is investigated and the improvement shows actually contribution to company's profit. Especially, the measurement issues related to heat and to quasi state of bandgap diagram by EL(Electro Luminescence) are described in this study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.87-89
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• 2019

The existing curriculum of cultural assets compulsory curriculum is difficult to expect educational effect due to lack of interests and visibility. The purpose of this study is to develop application contents and teaching materials using cultural data 3 - D data based on multi - marker recognition technology of augmented reality, which is attracting attention in the era of the 4th industrial revolution. In the case of the contents of a multi-marker technology capable of recognizing a plurality of markers, various events can be added and output capability can be enhanced. The proposed augmented reality app will be applied to the study of various education contents production technology utilizing cultural properties.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.99-103
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• 2021

Warpage defect detecting of scaffold is very important in biosensor production. Because warpaged scaffold cause problem in cell culture. Currently, there is no detection equipment to warpaged scaffold. In this paper, we produced detection model for shape warpage detection using deep learning based CNN. We confirmed the shape of the scaffold that is widely used in cell culture. We produced scaffold specimens, which are widely used in biosensor fabrications. Then, the scaffold specimens were photographed to collect image data necessary for model manufacturing. We produced the detecting model of scaffold warpage defect using Densenet among CNN models. We evaluated the accuracy of the defect detection model with mAP, which evaluates the detection accuracy of deep learning. As a result of model evaluating, it was confirmed that the defect detection accuracy of the scaffold was more than 95%.

• Journal of Fashion Business
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• v.24 no.6
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• pp.109-119
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• 2020

As interest in the environment increases, consumers increasingly choose to buy products with eco-friendly production processes. The purpose of this study was to determine the effect of consumption values and materialism/voluntary simplicity on the attitudes and purchase intentions toward eco-friendly fashion products. A survey of university students in Seoul was conducted and 203 questionnaires were analyzed using SPSS 23.0. The consumption values consisted of six factors: subjective value, novelty value, social value, brand value, practical value, and health/safety value. Materialism/voluntary simplicity was grouped into two factors of materialism pursuit and voluntary simplicity pursuit. Brand values were found to negatively affect attitudes toward eco-friendly fashion products. The more one pursued brand names, the more negative was one's attitude toward eco-friendly fashion products. Health/safety values had a positive effect on purchase intentions for eco-friendly fashion products and voluntary simplicity pursuit had a positive effect on both attitudes and purchase intentions. The materialist group had high subjective value, novelty value, social value, and brand value among the consumption values, and the voluntary simplicity-seeking group tended to pursue the value of health and safety. This study was meaningful in that it identified the characteristics of consumers showing favorable attitudes toward eco-friendly fashion products.