• Journal of Agricultural Extension & Community Development
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• v.23 no.4
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• pp.449-457
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• 2016

The purpose of this study are to examine the educational use of the Facebook and to examine the effects of the learners perceived usefulness, attitude and self-efficacy on learning flow and learning presence at university classes using social network service. The subjects of this study are 155 university students attending a class at a 4-year university in Seoul, and certain questions verified in the existing studies were modified, complemented, and used as a tool for measurement. The details of the purpose are as follows. First, it turned out that there were significant differences in learning flow and learning presence in accordance with the levels of the usefulness that learners perceived. It can be said that the higher the perceived level of usefulness, the higher the learning flow and learning presence. Second, it turned out that there were significant differences in learning flow and learning presence in accordance with the levels of learners' perceived attitudes. We can interpret such a result as suggesting that the higher a learner's perceived attitude, the higher the learning flow and learning presence.

• The Journal of Information Systems
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• v.31 no.2
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• pp.1-18
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• 2022

Purpose Customer review is a major factor in choosing certain restaurants. This study investigates the key factors affecting customer's evaluation about restaurants. With the recent intensification of competition among restaurants in the service industry, the analysis results are expected to provide in-depth insights for enhancing customer experiences. Design/methodology/approach We collected information and reviews provided at the restaurants in the Kakao Map platform. The information collected is based on the information of 3,785 restaurants in Daegu registered on Kakao Map. Based on the information collected, seven independent variables, including number of rating registered, number of reviews, presence or absence of safe restaurants, presence or absence of a posting about holding facilities, presence or absence of a posting about business hours, presence or absence of a posting about hashtags, and presence or absence of break times, were used. Dependent variable is restaurant rating. Multiple regression between independent variables and restaurant rating was carried out. Findings The results of the study confirmed that number of rating registered, presence or absence of a posting about business hours, and presence or absence of a posting about hash tags have an positive effects on the restaurant rating. The number of reviews had a negative effect on the restaurant rating. In addition, in order to confirm the role of customer's reviews, we carried out LDA topic modeling. We divided the topics into the positive review and the negative reviews.

• The Journal of the Korea Contents Association
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• v.21 no.11
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• pp.826-839
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• 2021

The purpose of this study was to provide instructional implications for synchronous online learning at universities by examining variables that influence the outcome of synchronous online learning and investigating the relationships of the variables. To achieve the purpose, self-regulated learning, social presence, learning engagement and perceived academic achievement were measured by 123 university students who had taken synchronous online learning for spring semester in 2020. The collected data were analyzed through SPSS and SPSS PROCESS macro. The results were as follows. First, self-regulated learning and learning engagement significantly predicted perceived academic achievement while social presence did not. Second, self-regulated learning had a direct effect on perceived academic achievement and had an indirect effect on perceived academic achievement through learning engagement. Third, social presence did not have a direct effect on perceived academic achievement, but had an indirect effect on perceived academic achievement through learning engagement. The implications based on the results were suggested.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1997.10a
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• pp.177-180
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• 1997

Outliers, unexpected extraordinary observations that look discordant from most observation in a data set are commonplace in various kinds of data analysis. Since the effect of outliers on model identification could be serious, the aim of this paper is to present some ways of handling outliers in given data set and to specify a model in the presence of outliers. A procedure based on neural network which identifies outliers, removes their effects, and specifies a model for the underlying process is proposed. In contrast with traditional parametric methods requiring to estimate the model's structure and parameters before detecting outliers, the proposed procedure is a nonparametric method without the estimation of model's structure and parameters before handling outliers and could be applied for real problems in the presence of outliers. The proposed methodology is performed as followings. Firstly, outliers are detected and the detected outliers replace the prediction values using outliers detection neural network. The data set removing the effect of outliers is retraining using neural network. Therefore the effects of outliers are removed and the modeling precision can be improved. Experimental results show that the proposed method is suitable for predicting data set in the presence of outliers.

• YAKHAK HOEJI
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• v.51 no.3
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• pp.169-173
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• 2007

The aim of this study was to investigate the effect of morin on the pharmacokinetics of nifedipine in rats. The pharmacokinetic parameters of nifedipine were measured after the oral administration of nifedipine (5 mg/kg) in the presence or absence of morin (1.5, 7.5 and 15 mg/kg, respectively). Compared to the control groups, the presence of 7.5 mg/kg and 15 mg/kg of morin significantly (p<0.05) increased the area under the plasma concentration-time curve (AUC) of nifedipine by 48.5${\sim}$68.2%, and the peak concentration (C$_{max}$,) of nifedipine by 59.9~84.2%. The absolute bioavailability(AB%) of nifedipine was significantly (p<0.05) increased by 21.5${\sim}$24.5% compared to the control (14.5%). While there was no significant change in the time to reach the peak plasma concentration (T$_{max}$) and the terminal half-life (T$_{1/2}$) of nifedipine in the presence of morin. It might be suggested that morin altered disposition of nifedipine by inhibition of both the first-pass metabolism and p-glycoprotein (P-gp) efflux pump in the small intestine of rats. In conclusion, the presence of morin significantly enhanced the oral bioavailability of nifedipine, suggesting that concurrent use of morin or morin-containing dietary supplement with nifedipine should require close monitoring for potential drug interaction.

• Asia pacific journal of information systems
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• v.32 no.2
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• pp.249-274
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• 2022

This study is to focuses on users' attitudes toward augmented reality games. Based on the Technology Acceptance Model (TAM) and Flow theory, continuous usage intention was set as a dependent variable, and immersion was set as a mediating variable. As independent variables, spatial presence, perceived interactivity, perceived pleasure, and sickness were set. Besides, this study strived to compare and analyze Korean and Chinese Data. The results of this study were as follows. First of all, Korean users significantly affected spatial presence, perceived pleasure, and immersion. Spatial presence and perceived pleasure had also mediated effects on continuous usage intention through immersion. However, perceived interactivity and sickness did not affect immersion and even no mediating effect to continuous usage intention. In the case of Chinese users, spatial presence, perceived interactivity, and perceived pleasure were grouped into one variable. This variable influenced immersion and also had mediated effect on continuous usage intention. However, sickness, like Korean users, did not affect the set path. This study had implications for analyzing user perspective using immersion, a significant variable in previous research. In addition, this study found similarities and characteristics through a comparative analysis between Korean and Chinese users indirectly.

• Science of Emotion and Sensibility
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• v.19 no.3
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• pp.71-80
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• 2016

The purpose of this study was to examine the effects of display on time on tasks and virtual presence in the immersive virtual reality. Head mounted display (HMD) and monitor conditions were compared when the participants were asked to complete navigation tasks in a virtual classroom. Time on tasks and virtual presence were measured. Three factors of the virtual presence were applied as dependent variables such as 1) spatial presence, 2) involvement, and 3) realness. The results showed that HMD condition took longer time to finish tasks than monitor conditions. HMD condition showed significantly higher perception from all of the virtual presence factors. Interestingly, there was a significant interaction effect between the display conditions and presence factors. The relationship between display types and virtual presence factors were discussed for future study.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.131-145
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• 2014

This study is an empirical analysis on the relationship between social presence and online community users' continuance intention. Based on Bhattacherjee(2001)'s expectation-confirmation model (ECM) of IT continuance model, we test the influence of social presence on one's intention to continue using online communities. This study sampled 132 online community users. Research hypotheses are tested using the structural equation modelling(SEM) approach. The results of this study demonstrate that user satisfaction is influenced by perceived usefulness and perceived enjoyment. But, the confirmation of expectation did not affect user satisfaction. And, social presence has direct effects on perceived usefulness and perceived enjoyment. Further, social presence has a positive effect on users' continuance intention through mediating effect of perceived usefulness. This study suggests that perceived usefulness should be taken into account when carrying out the operating strategy of online communities.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.439-449
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• 2018

The purpose of this study was to examine the effect of VR news focused on recall, understanding, enjoyment, visual fatigue and reuse intention through experimental study. Using Window SPSS 21.0 and AMOS 21.0 program, the data was analyzed by exploratory/confirmatory factor analysis, reliability analysis, correlation analysis and path analysis. The Results are as follows. First, presence and immersion among VR news characteristics influenced positively on users' recall of VR news. Second, presence, interactivity and immersion among VR news characteristics influenced positively on users' understanding of VR news. Third, presence, interactivity and immersion among VR news characteristics influenced positively on users' enjoyment of VR news. Fourth, presence among VR news characteristics influenced negatively on users' visual fatigue of VR news. Fifth, presence and immersion among VR news characteristics influenced positively on users' reuse intention of VR news. This study will provide on an important implication understanding VR news characteristics and VR news users.

• Journal of The Korean Association of Information Education
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• v.16 no.2
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• pp.151-164
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• 2012

The purpose of this study was to examine moderating effect of academic self-efficacy and learning flow between social presence and academic achievement of cyber university students. For this purpose, the 371 students of W cyber university were participated in the web-survey system for two weeks at the end of second semester in 2011. The results of this study through hierarchical multiple regression analysis indicated that social presence significantly predicted on academic achievement. Academic self-efficacy was not significant moderating variable between social presence and academic achievement. And Learning flow was used as a significant moderated variable in the relationships among social presence and academic achievement. Based on these study results, effective management strategies for improving cyber university students' academic achievement were proposed.