• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.137-147
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• 2013

The purpose of this study is to examine what variables influence on tweet credibility and attitude toward tweet. For this, the present research used the tweet content(information/opinion), tweet function(without URL and RT/URL/RT) and involvement(low/hight) as independent variables and applied a triangular research design which are in-depth interview, survey and computer usability testing software. Main findings are as follows. First, the participants read tweets listed in order regardless of tweet content, function and involvement. Second, there was a significant main effect of the tweet content on the tweet credibility and an interaction effect of those three independent variables on the attitude toward tweet. Finally, the in-depth interview showed that information is perceived to be more credible than opinion and URL>RT>just information or opinion are listed in order on the tweet credibility.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.552-560
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• 2020

Human carbonic anhydrase (CA) isozyme II has been used as protein target for disorder treatment including glaucoma. Current clinically used sulfonamide-based CA inhibitors can induce side effects, and so alternatives are required. This study aimed to investigate a natural CA inhibitor from Murraya paniculata. The previously developed yeast-based assay was used to screen 14 compounds isolated from M. paniculata and identified by NMR analysis for anti-human CA isozyme II (hCAII) activity. Cytotoxicity of the compounds was also tested using the same yeast-based assay but in a different cultivation condition. Two flavonoid candidate compounds, 5, 6, 7, 8, 3', 4', 5'-heptamethoxyflavone (4) and 3, 5, 7, 8, 3', 4', 5'-heptamethoxyflavone (9), showed potent inhibitory activity against hCAII with a minimal effective concentration of 10.8 and 21.5 μM, respectively, while they both exhibited no cytotoxic effect, even at the highest concentration tested (170 μM). The results from an in vitro esterase assay of the two candidates confirmed their hCAII inhibitory activity with IC₅₀ values of 24.0 and 34.3 μM, respectively. To investigate the potential inhibition mechanism of compound 4, in silico molecular docking was performed using the FlexX and SwissDock software. This revealed that compound 4 coordinated with the Zn²⁺ ion in the hCAII active site through its methoxy oxygen at a distance of 1.60 Å (FlexX) or 2.29 Å (SwissDock). The interaction energy of compound 4 with hCAII was -13.36 kcal/mol. Thus, compound 4 is a potent novel flavonoid-based hCAII inhibitor and may be useful for further anti-CAII design and development.

• Reproductive and Developmental Biology
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• v.39 no.4
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• pp.105-115
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• 2015

Toll-like receptor 7 (TLR7) is critical for the triggering of innate immune response by recognizing the conserved molecular patterns of single-stranded RNA (ssRNA) viruses and mediated antigenic adaptive immunity. To understand how TLR7 distinguish pathogen-derived molecular patterns from the host self, it is essential to be able to identify TLR7 receptor interaction interfaces, such as active sites or R848-agonist binding sites. The functional interfaces of TLR7 can serve as targets for structure-based drug design in studying the TLR7 receptor's structure-function relationship. In contrast to mammalian TLR7, chicken TLR7 (chTLR7) is unknown for its important biological function. Therefore, it has been targeted to mediate contrasting evolutionary patterns of positive selection into non-synonymous SNPs across eleven species using TLR7 conservation patterns (evolutionary conserved and class-specific trace residues), where protein sequence differences to the TLR7 receptors of interest record mutation that have passed positive section across the species. In this study, we characterized the Lys609 residue on chTLR7-ECD homodimer interfaces to reflect the current tendency of evolving positive selection to be transfer into a stabilization direction of the R848-agonist/chTLR7-ECDs complex under the phylogenetically variable position across species and we suggest a potential indicator for contrasting evolutionary patterns of both the species TLR-ECDs.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.8
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• pp.641-648
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• 2016

In this study, the effect of injection nozzle shape on the supersonic film cooling performance is analyzed using CFD. The design parameters are inside and outside angles of upper plate of nozzle and nozzle tip thickness. It is observed that the mass flow rate of film cooling decreases with increase of inside angle, while the effect of the change of mass flow rate on the film cooling effectiveness is relatively small. In addition, cooling performance is generally reduced, except ahead of the local region where shock wave interaction with film cooling occurs, in accordance with the growth of the outside angle and tip thickness. In this paper, the CFD simulation is performed using a commercial software, ANSYS Fluent V15.0, and the CFD model is validated by comparing it with the experimental data shown in preceding research.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.647-654
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• 2010

In this study, an efficient ornithopter aerodynamic model, which is applicable to ornithopter wing design considering fluid-structure interaction or ornithopter flight dynamics and control simulation, was proposed and experimentally validated through the wind tunnel experiments. Due to the ornithopter aerodynamics governed by unsteady low Reynolds number flow, an experimental device was specially designed and developed. A part of the experimental device, 2-axis loadcell, was situated in the non-inertial frame; the dynamic calibration method was established to compensate the inertial load for pure aerodynamic load measurements. The characteristics of proposed aerodynamic model were compared with the experimental data in terms of mean and root-mean-square values of lift and drag coefficients with respect to the flow speed, flapping frequency, and fixed angle of attack.

• Journal of Distribution Science
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• v.17 no.2
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• pp.101-107
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• 2019

Purpose - The purpose of this study is to analyze the user requirements and developer requirements in virtual reality(VR), and suggest ways to increase the satisfaction of users who experience virtual reality. Specifically, focused on experience store of VR as a distribution retailer, user requirements were analyzed according to the results of previous research that the characteristics of Affordance, Presence, and Head Mounted Display (HMD) affect user satisfaction. Research, design, data, and methodology - Based on previous studies, in this study, we analyzed the importance of immerse, interaction, perception, and presence for the satisfaction of the user through the questionnaire, and the user experiences virtual reality (VR) The importance of HMD, Presence, Affordance, and experience satisfaction were analyzed. Based on this, we analyzed the user requirements and the developer requirements based on the questionnaires and interviews of the experts, starting from the user's desire or preference using QFD technique. Results - As a result of the analysis, the development factors that occupied a big part in the virtual reality field appeared to be visual. In detail, this showed that there was a lack of sense of presence for users. This should be improved. This paper shows that the requirements for visual, auditory, and tactile development are necessary. For the satisfaction of the users of virtual reality (VR) users, it is necessary to develop them according to their priority in consideration of importance and difficulty in the future. Conclusions - In this study, it was suggested that development according to priority should be considered, considering the difficulty level. Based on the results of this study, the following suggestions are made. First, we tried to search the list of user requirements as much as possible, but it is likely to change due to the development of VR technology. Therefore, it is necessary for developers to continually supplement user requirements with recent research literature. Second, development priorities according to difficulty level should be considered. This aspect should be considered in the actual VR development process, so if the numerical value of the difficulty is calculated, it should be presented in the research.

• The Journal of Industrial Distribution & Business
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• v.10 no.1
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• pp.69-76
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• 2019

Purpose - The purpose of this paper is to empirically investigate the effectiveness of Offcial Development Assistance (ODA) in recipient countries' economy. ODA is designed to mitigate poverty and stimulate economic growth in the developing countries. We classify total ODA into bilateral ODA and multilateral ODA depending on the number of donor countries. If the ODA flows from one donor country to one recipient country, it is classified as bilateral ODA. If the multiple countries simultaneously become donor countries through the international organizations such as United Nations and World Bank, it is classified as multilateral ODA. This paper compares the effect of bilateral ODA and multilateral ODA in determining recipient countries' economic development, and tries to provide policy implications to Korean ODA. Research design, data, and methodology - Our primary explanatory variables are bilateral and multilateral ODA. Private credit in recipient countries is adopted as additional explanatory variables to capture the level of financial development in recipient countries. We measure the ODA effectiveness using economic growth and quality of life of the recipient countries as the dependent variable. We collect 142 recipient countries' data from OECD statistics, during the period from 1970-2014. Panel least squares estimation with country fixed effect is employed as the empirical model. Results - Our results support that ODA variable has a negatively significant impact on recipient countries' economic growth, while it is positively correlated with human development index. Recipient countries' private credit is positively correlated with economic growth and human development index. The interaction variable of ODA and financial development turns out to be significant in general. We find that the positive effect of ODA depends on recipient countries' financial market development and this effect is stronger in multilateral aid than bilateral one. Conclusions - From the analysis, we have confirmed that the recipient countries financial development is the necessity condition to achieve positive effect of ODA. Based on these results, we suggest that Korean government should increase the share of multilateral funding and pay attention to recipient countries' financial market development to maximize the effectiveness of ODA.

• The Journal of Industrial Distribution & Business
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• v.11 no.11
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• pp.39-53
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• 2020

Purpose: With a rapid advance of communication technology, distributional systems of sport contents continue to show improvements. In particular, a traditional framework in creating sport cartoon has been influenced by the environment of the communication industry. Despite the development of distributional systems, the current sport cartoon industry still lacks in advancement. To this day, various research about sport contents have been conducted; yet, not many studies of the interaction between sport cartoons and communication technology have been done. In this respect, this study is to review the distributional environment of the sport cartoon industry and provide distributional strategies for developing sport cartoon industry. Research design, data, and methodology: In addition to in-depth interviews with five practitioners in sport cartoon industry, the study employed case study methodology. Interview data were analyzed by qualitative content analysis. Results: With new environments allowing anyone allowing to create and share webtoons, various genres including sports webtoons appear, and this became amotive to the growth of sports webtoons. Today, sports comics acted as a sports advertisement platform which not only created additional profit but also became an opportunity as a marketing method. On the contrary, the formal attributes of webtoons cause hardship in consistently creating sports webtoons. Hence, it is needed that supporting policies need to be established to nurture sport webtoon expertise. For example, Korea Creative Content Agency allows future webtoon authors to have an opportunity to be educated and equipped in producing creative sport webtoon contents. Moreover, revenue systems should be developed for motivating webtoon authors to involve in sport contents in their works. Conclusions: In order to promote the sports cartoon industry based on the findings, it is first necessary to create sports comics that reflect the formal characteristics of webtoons and the changing consumer environment. Second, it is important to acknowledge the industrial value of sports comics and it is necessary to promote policies regarding sports webtoon production and distribution from a national level. Third, by diversifying profits through OSMU and sports advertisements, it is possible to enhance the work environment and the treatment of authors. Implications and future directions were discussed.

• The Journal of the Korea Contents Association
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• v.20 no.10
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• pp.268-283
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• 2020

The purpose of this study was to examine the effect of exposure to body image in media and bullet screen on weight loss intention by specifically focusing on Bilibili, a video sharing website of China. For the study, a 3 (Social viewing: no bullet screen vs. complimentary bullet screen vs. critical bullet screen) x 2 (Body image in media: ideal vs. realistic) between-subjects factorial design was conducted. A total of 310 Chinese women in their 20s were recruited to participate in an experimental survey. The main results showed that viewing the ideal body image with the complimentary bullet screen and realistic body image with the critical bullet screen strengthened the participants' intention on weight loss. Finally, the interaction effect of social viewing and the types of bullet screen were examined. The higher weight-loss intention was revealed when social viewing was conducted with the complimentary bullet screen of the ideal image. The results of this study can enhance the understanding of the bullet screen as a type of social viewing and its effect on user behavior intention.

• Journal of Advanced Navigation Technology
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• v.4 no.2
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• pp.103-113
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• 2000

There are several methods in the mathematical modeling of a satellite with flexible appendages. In this paper, the hybrid Lagrange's equations of motion using assumed modes method are derived. The assumed modes method is one of approximate methods which have shorter calculation time due to low-dimension compare with FEM. These consist of three-equations about angular velocities and two-equations about flexible deformations, and physically represent interaction between hub and solar panel. In an attitude control, a control law is designed to minimize a given performance index considering not only control input but also vibration suppression. For these purpose, this paper applies LQG and LQG/LTR schemes to this model and finally show the capability for attitude control including vibration suppression. Especially, this paper shows the method of assumption as nonsingular system through singular value division for LQG/LTR design.