• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.103-111
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• 2021

The purpose of this study is to study a method for preventing collisions of multiple drones in controlled airspace. As a result of the study, it was proved that it is appropriate as a method to control drone collisions after setting accurate information on the ROI (Region of Interest) area estimated based on the expected drone path and time in the control system as a method to avoid drone collision. As a result of the empirical analysis, the diameter of the flight path of the operating drone should be selected to reduce the risk of collision, and the change in the departure time and operating speed of the operating drone did not act as an influencing factor in the collision. In addition, it has been demonstrated that providing flight priority is one of the appropriate methods as a countermeasure to avoid collisions. For collision avoidance methods, not only drone sensor-based collision avoidance, but also collision avoidance can be doubled by monitoring and predicting collisions in the control system and performing real-time control. This study is meaningful in that it provided an idea for a method for preventing collisions of multiple drones in controlled airspace and conducted practical tests. This helps to solve the problem of collisions that occur when multiple drones of different types are operating based on the control system. This study will contribute to the development of related industries by preventing accidents caused by drone collisions and providing a safe drone operation environment.

• International Area Studies Review
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• v.22 no.1
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• pp.101-121
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• 2018

This paper studies the influence of multinational R&D Labs' expansion motives on their business performance and the mediating effect of the level of control on this motive-performance relationship. Through an in-depth study of the relevant literature, the expansion motives can be divided into four general types. The first is called a market factor in the sense that the purpose of their expansion is to secure potential markets and customers in China. The second is called a resource factor; their purpose is to obtain excellent technology and a workforce from the country. The third is called an institution factor. An example is the case of R&D Labs advancing into China to make the best of its institutional advantages such as the government's benefits, related policies, and incentive articles. The last is called a strategic factor and indicates the case where they go into China for the purpose of competing in the market, considering it as a major strategic place. The companies' control level on their R&D Labs was measured for each item. According to the empirical analysis on the relevance of their control level and expansion motives, it turns out that giving a free hand to the Labs which pursue market, institutional, and strategic factors is more desirable than highly controlling them. This is because they should be familiar with the local business environment in consideration of those companies' objectives. In light of the mediating effects of the control level on expansion motives and business performance, the R&D Labs pursuing resource factors seem to need their headquarters' control to make the best use of the high-end technology obtained in the country. The companies pursuing strategic factors seem to hold a dominant position and perform more competitively when their headquarters control the Labs more tightly.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.2
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• pp.127-137
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• 2019

Zr electrorefining is demonstrated herein using Zirlo tubes in a chloride-fluoride mixed molten salt in the presence of $AlF_3$. Cyclic voltammetry reveals a monotonic shift in the onset of metal reduction kinetics towards positive potential and an increase in intensity of the additional peaks associated with Zr-Al alloy formation with increasing $AlF_3$ concentration. Unlike the galvanostatic deposition mode, a radial plate-type Zr growth is evident at the top surface of the salt during Zr electrorefining at a constant potential of -1.2 V. The diameter of the plate-type Zr deposit gradually increases with increasing $AlF_3$ concentration. Scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX) and X-ray photoelectron spectroscopy (XPS) analyses for the plate-type Zr deposit show that trace amount of Al is incorporated as Zr-Al alloys with different chemical compositions between the top and bottom surface of the deposit. Addition of $AlF_3$ is effective in lowering the residual salt content in the deposit and in improving the current efficiency for Zr recovery.

• Journal of agriculture & life science
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• v.52 no.6
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• pp.27-36
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• 2018

Recently, the demand for new cultivar of oriental mustard(Brassica juncea) is increased as the consumption of oriental mustard has increased dramatically in the market due to Kimchi is attracting the world's attention. However, absence of seed supply system can cause many problems including inbreeding depression due to self seed production, deterioration of the seed purity and heterogeneity of commercial seed. To establish the $F_1$ variety breeding system of oriental mustard, pure line and inbred lines were screened from inbreeding genetic resources. Male-sterile line was also selected from breeding combinations for the quality improvement of mustard. The combining ability from(Indojasai ${\times}$ Goheungdamyang) combinations and isolation line of(MS910 ${\times}$ Japan red mustard 8 ${\times}$ Ganghwa mustard 9) was highest, thus these lines were selected as parental lines. PCR(Polymerase Chain Reaction) and gene sequence analysis revealed that the genes related to CMS(orf263, orf220, and orf288) were distributed in mitochondria. The isolated lines from this study also showed good performance in yield test and farmhouse prove test.

• Korean Journal of Environment and Ecology
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• v.35 no.2
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• pp.115-125
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• 2021

This study surveyed the population ecology of Acheilognathus chankaensis (Pisces: Acheilognathinae) in the vicinity of the Churyeongcheon (Stream) and Seomjingang (River) in Jeonbuk, Korea, from February 2006 to May 2007. The survey found the habits mainly in the slow-flowing waters having sand, mud, and gravel bottoms. Age groups estimated by the standard length-frequency distribution of the population indicated that the one-year-olds were 30-46 mm long, the two-year-olds were 47-58 mm long, the three-year-olds were 59-68 mm long, and the four-year-olds were longer than 69 mm. The gonadosomatic index (GSI) and the ratio of ovipositor length/standard length were the highest in March (♀: 12.9%, ♂: 5.0%) and in April (46.3%), respectively. The ratio of mature egg diameters that were 1.6 mm was highest in May (13.2%). The comprehensive analysis of spawning characteristics showed that the spawning season was from March to June with water temperatures in 11.5-22.5℃, and the sex ratio of female:male was 1:1.13. The fecundity in the ovaries and the number of mature eggs were 318±174.5 (50~583) and 220±139.2 (50~406), respectively. The size of the mature eggs was 2.04±0.110 mm on the long axis and 1.55±0.100 mm on the short axis for the study period. Gut contents of A. chankaensis were mainly phytoplankton such as the genera Fragilaria, Synedra, Navicular, Cymbella (Bacillariophyceae), and Cosmarium (Chlorophyceae).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.149-158
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• 2021

The aim of this study is to examine the relationships between high school student's self-efficacy and conversations with parents on career maturity. We consider how to instruct students in school life, efforts to increase students' career maturity and implications for career education in schools to evaluate students' school life. For the empirical analysis, the Korea Education and Employment Panel (KEEP II) survey data conducted in early 2018 was used. Study results found self-efficacy has a significant positive (+) effect on career maturity and a significant positive effect on conversations with parents. The frequency and content of conversation with parents have a significant positive (+) effect on career maturity. The effect of self-efficacy and conversations with parents variables on career maturity has a significant regulatory effect between the two groups who were satisfied with school life and those who were not.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.69-76
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• 2020

Global warming is a very important problem as it causes rapid climate change and natural disasters. Therefore, researches related to renewable energy are being actively conducted while promoting policies such as reducing carbon dioxide emission and increasing the proportion of renewable energy. Solar power generation is being applied in urban areas like BIPV as well as existing idle areas outside the city. Therefore, in this study, precast concrete blocks developed for paving roadways capable of solar power generation were designed and constructed. For the evaluation of field applicability for 6 months, skid resistance and block settlement were measured. As a result of the experiment, it was found that skid resistance satisfies the standard of general roadway in Korea, but not the standard of highway. The skid resistance tended to decrease as time passed. In addition, the settlement of the block gradually increased slightly, but it is much smaller than the allowable settlement of the roadway. Therefore, it is necessary to establish a maintenance period and method based on the periodic measurement results in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.138-148
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• 2021

This study explores the factors that moderate the impact of competitive strategy on resource sharing in order to explain why existing empirical research has not shown statistically significant results. We test the hypothesis that competitive strategy pursuing low-cost rather than differentiation increases resource sharing and analyze how the relationship between competitive strategy and resource sharing changes when diversification, interconnectedness, centralization of authority, and resource level are entered into the equation as moderating variables. According to the results, competitive strategy doesn't affect resource sharing alone, but it has significant effects on resource sharing when it is combined with interconnectedness, centralization of authority, and resource level, except for diversification. This means that low-cost strategy increases resource sharing under the conditions of high interconnectedness, more centralized authority, and low resource level. The prior discussions have focused on the willingness or intentions of resource sharing without considering the abilities or possibilities. Our findings indicate that resource sharing could be better predicted by using moderating variables reflecting the abilities or possibilities. The contribution of the study is that we discover and complement the vulnerability in the logic of resource sharing.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.83-91
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• 2022

Seismic design and analysis of nuclear power plant components are performed based on an decoupled model. However, this decoupled analysis has a limitation in that it generates inaccurate results compared to the coupled analysis because it cannot simulate actual phenomena such as the interaction between structures and components. Thus, this study performed seismic coupled and decoupled analysis on an existing nuclear containment structure and related components, considering the mass and natural frequency ratios. And based on these results, comparative analyses of responses of components were conducted. Consequently, the seismic coupled analysis result generally gave a smaller value than the decoupled analysis result. These results were similar to the analysis results for the simple coupled model, which was an existing study, but the difference in component responses was much more pronounced. Also, this was influenced by the installation location of the component rather than the influence of the input frequency of the input seismic motions. Finally, the difference between the decoupled and coupled seismic analysis occurred in the region where the mass ratio of the components was large, and the natural frequencies were almost similar due to the considerable dynamic interaction between the structure and the component in this realm.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.261-270
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• 2022

For mobile online games, this study examines how use pursuit propensity, use interest, use, service quality, and system quality, which are attributes that evaluate the use value and benefit for Chinese users, have an effect on use satisfaction. Empirical analysis results; all composing factors of four attribute had a positive effect, and the degree of effect was different according to game types in use interest and use, service quality. In terms of use pursuit, there was no difference between game types, and innovation pursuit and relationship pursuit were found to be similarly important effecting factors. In terms of use interest, there was a difference between game types. Sense of solidarity in single-player game and sense of achievement in multi-player game was found to be the most important effecting factor. In terms of service quality, there was a difference between game types. Easy of game in single-player game and function of game in multi-player game was the most important effecting factor. In terms of system quality, use convenience was found the most important effecting factor without difference between game types. Based on these results, this study suggested a strategy to enhance game development and loyalty to companies in the game industry.