• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.404-413
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• 2022

As non-face-to-face classes have been adopted as an essential class method in universities after COVID-19, interest in ways to encourage student engagement is increasing. Class engagement is a prerequisite for improving the quality of education, so it is inevitably an even more important requirement in non-face-to-face classes. Therefore, this study examined the efforts and concerns based on the teaching experiences of three professors of D University, which have been operated by mixing non-face-to-face or non-face-to-face classes since 2020. As a result, both professors and students went through trial and error in the early stages of non-face-to-face classes, but over time, it was confirmed that students not only actively expressed their opinions but also voluntarily expanded the class activity. This study is meaningful in that it found the possibility that professors-led classes can develop into learner-participating classes through appropriate harmony between face-to-face and non-face-to-face and the use of various media. Data were collected through an autobiographical method.

• Smart Media Journal
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• v.12 no.6
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• pp.15-26
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• 2023

As face-to-face communication has become difficult due to the COVID-19 pandemic, studies have been conducted to understand the impact of non-face-to-face communication, but there is a lack of research that examines this through messenger application reviews. This study aims to identify the impact of the pandemic through Latent Dirichlet Allocation (LDA) topic modeling by collecting review data of 메신저 applications in the Google Play Store and suggest service strategies accordingly. The study categorized the data based on when the pandemic started and the ratings given by users. The analysis showed that messenger is mainly used by middle-aged and older people, and that family communication increased after the pandemic. Users expressed frustration with the application's updates and found it difficult to adapt to the changes. This calls for a development approach that adjusts the frequency of updates and actively listens to user feedback. Also, providing an intuitive and simple user interface (UI) is expected to improve user satisfaction.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.4
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• pp.67-76
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• 2024

In this study, we address the problem of target detection using multiple agents. Specifically, the detection problem involving mobile agents necessitates additional strategies for path planning. The objective is to maximize the total utility derived from the detection process over a specific period. This detection problem incorporates realistic utility values by considering a stochastic process based on the Poisson process, which accounts for the changing probability of target event occurrence over time. The objective function is nonlinear and is classified as an NP-hard problem. To identify an effective solution within an efficient computation time, this study demonstrates that the objective function possesses the characteristic of submodularity. Using this property, we propose a heuristic algorithm designed to obtain a reasonable strategy with relatively low computational time. The proposed algorithm shows solution performance and the ability to generate solutions within an appropriate computation time through theoretical and experimental results.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.14-19
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• 2007

This study was conducted to analyze the antioxidant activity and xanthine oxidase inhibitory effect of hot-water extracts from Elaeagnus multiflora Thunb. to provide fundamental data for the development of functional materials. The antioxidative activities of hot-water extracts from E. multiflora Thunb. were analyzed by electron donating ability (EDA) using 1,1-diphenyl-2-picryl hydrazyl (DPPH), superoxide dismutase (SOD) -like activity by pyrogallol and nitrite scavenging ability. EDA of extracts from unripe, ripe, and overripe fruits were 77.7%, 36.0%, and 23.7% at 100 ${\mu}g/mL$, respectively, and EDA of extract in unripe fruits was higher than those of others. At 1,000 $\mu$g/mL, the SOD-like activities were 32.8%, 11.2% and 5.0% for unripe, ripe, and overripe fruits, respectively. The SOD-like activity was increased along with the increase of unripe and ripe extract concentrations. The nitrite scavenging ability of unripe fruit extracts in 100, 300, 500 ${\mu}g/mL$ of extraction solution in pH 1.2 and 3.0 was higher than those of others. The nitrate scavenging ability of all extracts was decreased according to the increase of pH. Xanthine oxidase inhibitory activities of unripe, ripe and overripe fruits were 30.0%, 28.2%, and 18.2% at 1,000 ${\mu}g/mL$, respectively.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.157-170
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• 2014

Professional coffee shops are trying to increase customers' satisfaction and to invite more customers by providing the differentiated services. The existing researches show that the effects which the physical environment in shops has on customers' satisfaction and word of mouth intention are appealing to people's attention. In comprehensively examining the studies related to the physical environment, they can be summarized into two main perspectives, that is, the direct effect that the physical environment has on customers' satisfaction, quality perception, and other customers' responses (purchase desire, revisit intention, etc.) and the indirect effect that the physical environment has on customers' responses by means of customers' emotion or value perception. This research established 4 hypotheses by sampling 321 customers of those who have visited professional coffee shops, and empirically analyzed them. The empirical analysis carried out the structure analysis of covariance by using SPSS 17.0 statistics package and AMOS 17.0. As a result of the hypothesis qualification, the other hypotheses excluding one little hypothesis were adopted. The one refused hypothesis is that the only symbolism of the environmental elements in shops doesn't influence the customers' emotion positively (+). This is considered as a very unexpected result, and yet many customers who visit coffee shops express the symbols of professional coffee shops using the expressions such as 'bean coffee shop' or 'star coffee shop', but these expressions seem not to influence customers' mind positively in practice.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.9
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• pp.1776-1785
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• 2015

Content Centric Network (CCN) has been introduced as a new paradigm due to a shift of users's perspective of using Internet from host-centric to content-centric. On the other hand, a demand for video streaming has been increasing. Thus, Adaptive streaming has been introduced and researched for achieving higher user's satisfaction. If an architecture of Internet is replaced with CCN architecture, it is necessary to consider adaptive video streaming in CCN according to the demand of users. However, if the same rate decision algorithm used in Internet is deployed in CCN, there are a limitation of utilizing content store (CS) in CCN router and a problem of reflecting dynamic requirements. Therefore, this paper presents a framework adequate to CCN protocol and cache utilization, adapting content naming method of exploiting regular expression to the rate decision algorithm of the existing adaptive streaming. In addition, it also improves the quality of video streaming and verifies the performance through dynamic expression strategies and selection algorithm of the strategies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.85-92
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• 2018

Reductions of the electricity charge are achieved by demand management of the load. The demand management method of the load using ESS involves peak shifting, which shifts from a high demand time to low demand time. By shifting the load, the peak load can be lowered and the energy charge can be saved. Electricity charges consist of the energy charge and the basic charge per contracted capacity. The energy charge and peak load are minimized by Linear Programming (LP) and Quadratic Programming (QP), respectively. On the other hand, each optimization method has its advantages and disadvantages. First, the LP cannot separate the efficiency of the ESS. To solve these problems, the charge and discharge efficiency of the ESS was separated by Mixed Integer Linear Programming (MILP). Nevertheless, both methods have the disadvantages that they must assume the reduction ratio of peak load. Therefore, QP was used to solve this problem. The next step was to optimize the formula combination of QP and LP to minimize the electricity charge. On the other hand, these two methods have disadvantages in that the charge and discharge efficiency of the ESS cannot be separated. This paper proposes an optimization method according to the situation by analyzing quantitatively the advantages and disadvantages of each optimization method.

• Journal of the Korean earth science society
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• v.31 no.3
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• pp.267-275
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• 2010

The purpose of this study is to investigate student's Acquisition about the conception of the Earth Rotation between difference of their Spatial Sensibility. In this study, four students were selected out of 83 9th graders in Gwangju, Korea. The spatial sensibility test instrument was developed by the Korean Testing Center, and the test instruments of 'the movement of celestial bodies' were developed by Kim (1997). The results were as follows: Students with higher spatial sensibility understood precisely about the Earth's rotation in stereoscopic space. However, those with lower spatial sensibility failed to grasp the Earth's rotation and memorized it as fragmentary concepts. As for gender effect, male student with higher spatial sensibility explained the concepts clearly, while that with lower spatial sensibility has difficulty with the Earth's rotation in relation to the diurnal motion of celestial bodies. On the other hand, female student with higher spatial sensibility explained the concepts correctly in detail, while that with lower spatial sensibility had difficulty explaining the concepts in stereoscopic space. Therefore, students with higher spatial sensibility should be presented with problems in which they form their own solution. Those with lower spatial sensibility should be allowed to understand the phenomena intuitively. In developing teaching methods, female students should interact with the concepts in stereoscopic space directly, while male students should consider the celestial objects from various viewpoints. Then spatial sensibility in relation to the movement of celestial bodies would be expected to improve.

• Culinary science and hospitality research
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• v.17 no.4
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• pp.185-203
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• 2011

It's hard for hotel organizations to survive without adaptation to changing environment, and employees' positive attitude are required. The empirical objectives of the study include, firstly, to identify individual factors to influence hotel employees' attitude toward organizational change, secondly, to investigate the effects of the individual factors on their attitude toward organizational change mediated through trust in management Derived from existing literature, three underlying dimensions of the individual factors are given; (1) satisfaction with information, (2) freedom to express opinion, and (3) input from employees. An experimental design is applied to test four hypotheses that reflect the research questions. Five star hotels in Korea are targeted to be surveyed. A total of 156 faithful cases out of 300 cases are analyzed in this study. Descriptive statistics and multivariate analysis of variance, and SEM are utilized employing the SPSS and AMOS 7. Results of this study indicate that satisfaction with information, freedom to express opinion, and input from employees are significantly related to hotel employees' attitude toward change mediated through trust in management. At the same time, it shows that trust in management directly influences their attitude toward organizational change. In conclusion, the findings of the study contribute to hotel organizational development.

• Management & Information Systems Review
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• v.31 no.2
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• pp.21-39
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• 2012

To examine how usage of social network services(SNS) can affect users' satisfaction through their involvement to SNS. This study first explored the usage motives on the SNS by reviewing previous studies which are from the perspectives of usage and gratification theory. The structural equation modeling(SEM) approach was used to validate the model and Lisrel was used to analyze 306 data which were collected from college students who have SNS using experiences. The results showed that the motives of information seeking and self-expression have no significant influence on affective involvement to SNS and other hypotheses were all accepted. In order to investigate the relationship of usage motives-involvement-satisfaction between different genders, path analysis in male group and female group were done respectively. The results showed that in the case of male group, the motivation of information seeking, entertainment, and self-expression have positive effect on affective involvement, while only the entertainment motive can increase the cognitive involvement. In the case of female group, socializing motive and entertainment motive have positive effect on both affective involvement and cognitive involvement, but the information seeking motive and self-expression motive can not influence the formulation of emotion in SNS.