• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.42-50
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• 2011

Using EEG, human physiological signal, as part of research which investigates the state of student learning and provides appropriate feedback to maximize learning efficiency, the relationship of learning attitude and analysis of EEG for female college student is presented. We study the reaction of learner's EEG using the concentration level extracted from the EEG power spectrum when students learn at various learning attitude. The experiment was conducted for the concentrating on learning and, as a control group, erratic attitude and closed eyes state. The attitude of concentrated Learning shows high concentration index and low relaxation index, where as the erratic attitude, such as eye movement and clicking, shows high level of attention index and noisy wave ratio. Especially, the state of closed eyes shows the ratio of alpha and theta wave under 1. This is distinct with open eyes cases.

• Journal of the Korea Convergence Society
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• v.12 no.7
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• pp.7-17
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• 2021

This study investigated the effect of size recommendation technology convergence on purchase intention mediated by information credibility and satisfaction. The survey for this study was conducted on Amazon Mechanical Turk targeting U. S. residing women aged 18 to 60 years old who have never used size recommendation technology. They experienced the size recommendation technology in the provided web page and returned to the survey to answer the questionnaire. The analysis was done with 213 surveys using SPSS 27.0 and Process Macro (model 6, 5,000 Bootstrapping sample). The dimensions of service quality were found to be responsiveness and ease of use, and both have a significant effect on purchase intention through information credibility and satisfaction.

• Korean Journal of Cognitive Science
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• v.20 no.3
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• pp.275-289
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• 2009

A new computerized testing system, called the Computerized Multiple-choice Testing (CMMT) system, was introduced. In this system, questions of multiple choice (MC) items are presented first without options, so that students must generate answers for themselves. They can click for the options when they are ready, and can respond within a brief, specified time period. The present study was performed to examine whether this system is effective in reducing backward reasoning, I. e., using the options of MC items as cues to find the correct answer. One hundred and seventy-seven 6th grade students (12 year olds) were divided into two groups so that mean scores from a prior test were equal: The experimental group took an intervening computerized test in the new format, and the control group in the MC format. Five days after the computerized intervening test, a short answer paper-and-pencil final test was given. Testing effect was greater in the new system than in the MC system. Analysis of the final test response in relation to the intervening test response showed that i) the students retained the correct answer in the new system more than in the MC testing system, and that ii) students corrected their previous failures in the intervening CMMT format more than those in the MC format. These results suggest that the new system is effective in reducing backward reasoning.

• Elastomers and Composites
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• v.48 no.1
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• pp.10-17
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• 2013

Polyolefin-g-poly(t-butylstyrene) as one of the high-temperature polyolefin-based thermoplastic elastomers was synthesized by the graft-from anionic living polymerization from the styrene moieties of the linear poly(ethylene-ter-1-hexene-ter-divinylbenzene) as a soft block to form the hard end blocks, poly(t-butylstyrene). The chemistry of the anionic graft-from polymerization involved complete lithiation of the pendant styrene unit of the soft polyolefin elastomer with sec-BuLi/TMEDA followed by the subsequent graft anionic polymerization of 4-tert-butylstyrene with Mn=10,000~30,000 g/mol. The graft-from living anionic polymerization were very effective and the grafting size increased proportionally with increasing monomer concentration and the reaction times. The synthetic methodology for the multi-hydroxyl chain-end modified polyolefin-g-poly(t-butylstyrene) was proposed by using the thiol-ene click reaction between 2-mercaptoethanol and the polyolefin-g-[poly(t-butylstyrene)-b-high vinyl polyisoprene], which was obtained from the subsequent living block copolymerization using polyolefin-g-Poly(t-butylstyrene) with isoprene. The result indicated that this process produced a new well-defined functionalized graft-type polyolefin-based TPE with high $T_g$ hard block(> $145^{\circ}C$).

• Journal of Life Science
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• v.29 no.7
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• pp.755-761
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• 2019

Kojic acid (KA) is produced by Aspergillus oryzae-sort of like mushrooms, which is commonly called as koji in Japan. KA is used as a chelation agent and a preservative preventing oxidative browning of fruits. KA also shows antibacterial and antifungal properties. Because KA stops the production of melanin by inhibiting tyrosinase in the biosynthetic pathway from tyrosine to melanin in skin, it has been applied as a skin lightening ingredient in cosmetics. Since some animal studies have shown that high amounts of KA had side effects such as in liver, kidney, reproductive, cardiovascular, gastrointestinal, respiratory, brain, and nervous system, more efficient KA derivatives are needed to be developed in order to safely apply as a skin lightening ingredient. A series of KA derivatives via conjugated with triazole by click reaction were synthesized and their in vitro tyrosinase inhibitory activities were evaluated. Most of all KA derivatives have shown in moderate tyrosinase inhibitory activities. In case of KA-hybrid compound, 1~3 have shown tyrosinase inhibitory activities about 50~10,000 times more effective tyrosinase inhibitor compared to KA itself. Specifically, the $IC_{50}$ value of KA-hybrid compound, 2 was $0.0044{\pm}0.74{\mu}M$ against tyrosinase. It is about 10,000 times more effective tyrosinase inhibitor compared to KA itself ($IC_{50}=45.2{\pm}4.6{\mu}M$).

• Journal of Service Research and Studies
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• v.13 no.3
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• pp.1-19
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• 2023

Despite the growing importance of video-based social media content, such as vlogs, as a marketing tool in the travel industry, there is limited research on the characteristics that enhance engagement among potential travelers. This study explores the influence of emotional valence in YouTube travel content on viewer engagement, specifically likes and comments. We analyzed 4,619 travel-related YouTube videos from eight popular tourist cities. Using negative binomial regression analysis, we found that both positive and negative emotions significantly influence the number of likes received. Videos with higher positive emotions as well as negative emotions receive more likes. However, when it comes to the number of comments, only negative emotions showed a significant positive influence, while positive emotions had no significant impact. These findings offer valuable insights for marketers seeking to optimize engagement strategies on YouTube, considering the unique nature of travel products. Further research into the effects of specific emotions on engagement is warranted to improve marketing strategies. This study highlights the powerful impact of emotions on viewer engagement in the context of social media, particularly on YouTube.