• Honam Mathematical Journal
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• 제30권4호
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• pp.743-748
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• 2008

In this article, we study ruled hypersurfaces in a Lorentz-Minkowski space which has finite type immersion. As a result, we give a complete classification of ruled hypersurfaces or finite type immersion into a Lorentz-Minkowski space ${\mathbb{L}}^m$.

• Proceedings of the KWS Conference
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• 대한용접접합학회 2004년도 춘계 학술발표대회 개요집
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• pp.293-295
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• 2004

For the evaluation of corrosion resistance, Al 6061-T6 alloy was welded by Friction Sti. Welding(FSW) and Gas Metal Arc Welding(GMAW) evaluated by Tafel method and immersion test. The Tafel and immersion test results indicated that GMA weld was severely attacked compared with those of friction stir weld. It may be mainly due to the galvanic corrosion mechanism act on the CMA weld.

• International journal of advanced smart convergence
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• 제10권1호
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• pp.38-55
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• 2021

Recently, the use of media has become a daily life due to Covid-19, and education using media has expanded for teenagers. The purpose of this study is to empirically verify how media usage characteristics affect social relationships and school adaptation through the self-efficiency and immersion of teenagers at the youth education site. This study was collected and distributed questionnaires to 250 high school students in Seoul from November 14 to November 21, 2020. The results of the study were derived with a total of 249 questionnaires, excluding one missing questionnaire, and the hypothesis was verified using a Covariance Structure Analysis. Research has shown that, first, the existing, individual, and utility among the characteristics of using youth media have a significant effect on self-efficiency, respectively. Second, only entertainment among the characteristics of youth media use was found to have a significant effect on immersion. Third, immersion has a significant definition effect on school adaptation, and self-efficiency has been shown to have a definition impact on social relationships. Based on this study, we believe that it will be used as a fundamental resource for the development of youth media usage and policy direction in the age of the ever-changing Covid-19.

• Journal of the Korean Crystal Growth and Crystal Technology
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• 제28권5호
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• pp.199-205
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• 2018

A geopolymer was produced from coal ash generated from an integrated gasification combined cycle (IGCC) plant and its water resistance was evaluated. For this purpose, the geopolymer specimens were immersed in water for 30 days to measure changes in microstructure and alkalinity of the immersion liquid. Particularly, the experiment was carried out with foaming status of the geopolymers and parameters of room temperature aging condition, and immersion time. The foamed geopolymer containing 0.1 wt% Si-sludge had pores with a diameter of 1 to 3 mm and exhibited excellent foamability. Also, the calcium-silicate-hydrate crystal phase appeared in the foamed geopolymer. In the geopolymer immersion experiment, the pH of the immersion liquid increased with time, because the un-reacted alkali activator remained was dissolved in the immersion liquid. From the pH change of the immersion liquid, it was found that geopolymer reaction in the foamed specimen was completed faster than the non-foamed specimen. Through this study, it was possible to successfully produce foamed and non-foamed geopolymers recycled from IGCC coal ash. Also the necessary data for the safe application of IGCC coal ash-based geopolymers to areas where water resistance is needed were established; for example, the process conditions for room temperature aging time, effect of foaming status, immersion time and so on.

• Journal of Convergence for Information Technology
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• 제9권11호
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• pp.171-179
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• 2019

This study aims to examine whether a Parent's Neglecting Attitude affects an Adult Media Immersion and Adolescent' Dependence on mobile phonehas a mediating effect. To achieve this goal, the first year of middle school panel of 'the 6th Korean Children and Youth Panel Survey(KCYPS)' was utilized. To verify the mediating effect of Adolescent' Dependence on mobile phone in the relationship between Parent's Neglecting Attitude by Adolescents and the Adult Media Immersion, Baron & Kenny's mediating effect analysis method was conducted and the analytical findings are shown below. According to this study, first of all, more the Parent's Neglecting Attitude rise to rise the Adult Media Immersion. Second, the Adolescent's Dependence on mobile phone partly mediates the Adult Media Immersion. The practical implications of this results are below : First, we need to make a policy and legal effort to improve the relationship between parents and children. Second, there is a need to practice professional programs in schools, focusing on school social worker. Third, Revision of relevant laws limiting access to adult media is necessary.

• The Journal of the Korea Contents Association
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• 제21권2호
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• pp.474-488
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• 2021

The application of Augmented Reality(AR) technology is visible in medical procedures, education, marketing, and journalism. By experimenting, this study examines how the evaluation of the three elements of augmented reality news contents(visual image, storytelling, interactivity) affects immersion and information acquisition. Specifically, a 2 (video technology: AR vs. general) × 2 (news type: disaster vs. sports) between-subject design was examined. Results showed that the evaluation of all three elements was higher when viewing AR news than when viewing general news. The level of immersion was higher when viewing AR news, and the evaluation of storytelling and interactivity had positive effect on the level of immersion regardless of the news types. However, the evaluation of visual images did not affect the level of immersion. Information acquisition was higher after viewing AR news, yet the effect of the evaluation of the three elements on information acquisition had not been found. Implication and discussion of the study were added in the end.

• International Journal of Contents
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• 제18권1호
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• pp.1-16
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• 2022

With the advent of the 5G, networks and information and communication technologies have been continuously developed. In the fields of art galleries, virtual reality (VR) exhibitions that can be visited online have emerged, innovating the way of human-computer interaction and creating new artistic experiences for users. This study explores the three-dimensionality, clarity, and innovative interactions that users experience when viewing a VR exhibit, which affects the exhibit's presence. Besides, in terms of research method, the research sets spatial participation and immersion as dependent variables, with three-dimensionality (high versus low), clarity (high versus low), and innovation (high versus low) in a 2×2×2 design as the base, and explores their interaction effects. The results show that three-dimensionality and innovative interactions affect spatial participation. First of all, in groups with high innovation and low three-dimensionality, spatial participation presents a higher positive factor. Secondly, with regard to immersion, three-dimensionality, clarity and innovation present a tripartite interaction. Groups with low three-dimensionality and high clarity have a higher positive effect on immersion when the level of innovation is low. When the degree of innovation is high, the positive effect on immersion is higher in groups with high three-dimensionality and low clarity. The above results show that in the production of VR exhibitions, it is necessary to increase the three-dimensionality and clarity of exhibited image contents, while taking into account the user's perception and innovativeness. On the other hand, this study puts forward suggestions for the design, content and future development of VR exhibitions, which has important reference significance for the improvement and innovation of future VR exhibitions.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제46권2호
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• pp.13-21
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• 2023

In the recent era of the fourth industrial revolution, many industries aim to maximize the efficiency of products and services by introducing cutting-edge technologies such as artificial intelligence and big data. In this situation, organizational culture is changing a lot due to the influx of the MZ generation with strong individualistic tendencies and the decreased face-to-face communication between members. However, active communication with colleagues is still essential to maximize performance, and the margins created by simplifying work processes and automating processes must be used for creating work performance. This requires cooperation and commitment through the job immersion of members who have an active attitude. This study analyzed how the organization's autonomous work environment and trust among members, which are creative work performance conditions, affect job immersion using raw data from the Occupational Safety and Health Research Institute. As a result, it was found that both the organization's autonomous working environment and trust among members significantly effected the members' job immersion. in order to achieve productivity and value improvement in companies, efforts are needed to increase workers' job immersion by building an autonomous working environment and trust among members. The results of this study are expected to contribute significantly to the search for ways to increase workers' job commitment to improve organizational productivity.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• 제20권2호
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• pp.1-10
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• 2024

The introduction of the sector coupling concept has expanded the scope of ESS utilization, resulting in the importance of thermal management of ESS. To ensure the safe use of the lithium-ion batteries that are used in ESS, it is important to use the batteries at the optimal temperature. To examine the utilization of liquid cooling in ESS, numerical study was conducted on the thermal characteristics of 21700 battery modules (16S2P array) during liquid cooling using Novec-649 as insulating fluid. The NTGK model, an MSMD model in ANSYS fluent, was used to investigate thermal characteristics on the battery modules with liquid immersion cooling. The results show that the final temperature of the battery module discharged at 5 C-rate is 68.9℃ using natural convection and 48.3℃ using liquid cooling. However, the temperature difference among cells in the battery module was up to 0.5℃ when using natural convection cooling and 5.8℃ when using liquid cooling, respectively, indicating that the temperature difference among cells was significantly increased when liquid cooling was used. As the mass flow rate increased from 0.01 kg/s to 0.05 kg/s, the average temperature of the battery module decreased from 48.3℃ to 38.4℃, confirming that increasing the mass flow rate of the insulating fluid improves the performance of liquid immersion cooling. Although partial liquid immersion cooling has a high cooling performance compared to natural convection cooling, the temperature difference between modules was up to 8.9℃, indicating that the thermal stress of the battery cells increased.

• Journal of fish pathology
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• 제17권3호
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• pp.171-177
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• 2004

This study was performed to investigate the effects of prolonged immersion vaccination in a dilute vaccine on the farmed olive flounder, Pararlichthys olivaceus. Juvenile olive flounders were immersed in the several diluted ($10^0$, $10^{-1}$, $10^{-2}$ and $10^{-3}$) commercial edwardsiellosis bacterins (5㎎/ℓ) for 2min (short immersion, SI) and 24 h (prolonged immersion, PI). After immunization, fish were analyzed to investigate on non-specific (serum lysozyme and bactericidal activity), specific immune responses (antibody agglutinin titer) and resistances against Edwardsiella tarda infection. The PI of the commercial vaccine diluted with $10^{-1}$ and $10^{-2}$ showed better results over the untreated control in terms of serum lysozyme, bactericidal activities and resistance against E. tarda infection. These results suggest that the prolonged treatments of the diluted vaccine might be a new approach improving the vaccination potential.