• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.15-22
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• 1996

In the soliton transmission system for a long-length and high bit rate data transmission systme using the nonlinear/dispersive optical fibers, the improtant problem is the loss characteristics and is the limited transmission rate by interaction forces. In this paper, It is explained the reasons of moved time position for the soliton peak value due to interaction force sof adjacent solitons. And for the analysis of interaction force affection level in the losslessmedia, we define the percent parameter of error rate due to the interaction forces and propose the optimum time distance of adjacent solitons by peak value tracking methods. With the results, initial percent of error is approximately 50% when itme difference between adjacent solitons is 5 times of funddametnal soliton pulse width. And it is confirmed that maximum transmission length of th esolitons is approximately 38 times of fundamental soliton period, which the maximum allowable percoent of error is 50%.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.57-70
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• 2008

A high-order accurate Euler flow solver based on a discontinuous Galerkin finite-element method has been developed for the numerical simulations of blade-vortex interaction phenomena on unstructured meshes. A free vortex in freestream was investigated to assess the vortex-preserving property and the accuracy of the present flow solver. Blade-vortex interaction problems in subsonic and transonic freestreams were simulated by adopting a multi-level solution-adaptive dynamic mesh refinement/coarsening technique. The results were compared with those of other numerical and experimental methods. It was shown that the present discontinuous Galerkin flow solver can preserve the vortex structure for significantly longer vortex convection time and can accurately capture the complex unsteady blade-vortex interaction flows, including generation and propagation of acoustic waves.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.57-70
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• 2008

A high-order accurate Euler flow solver based on a discontinuous Galerkin finite-element method has been developed for the numerical simulations of blade-vortex interaction phenomena on unstructured meshes. A free vortex in freestream was investigated to assess the vortex-preserving property and the accuracy of the present flow solver. Blade-vortex interaction problems in subsonic and transonic freestreams were simulated by adopting a multi-level solution-adaptive dynamic mesh refinement/coarsening technique. The results were compared with those of other numerical and experimental methods. It was shown that the present discontinuous Galerkin flow solver can preserve the vortex structure for significantly longer vortex convection time and can accurately capture the complex unsteady blade-vortex interaction flows, including generation and propagation of acoustic waves.

• Educational Technology International
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• v.22 no.2
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• pp.199-225
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• 2021

The aim of the current study was to suggest priorities needed to be considered by university instructors when designing online learning. Based on three types of interactions (learner-content, learner-instructor, and learner-learner interactions) for effective online learning (Moore, 1989), draft questionnaires representing each type of interaction were written. After examining content validity by two Ph.D. experts, the survey was constructed with an Importance-Performance Analysis (IPA) form. Data of 133 university instructors were collected online. Results showed that support for designing learner-learner interaction was the priority for improving online learning. In terms of learner-instructor interaction, instructors needed to provide social-emotional support to learners so that learners could have a sense of belonging. For learner-instructor interaction, supporting instructors to monitor the level of understanding was the most highly demanding strategy for online learning. Limitations and suggestions for further studies were discussed.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.117-126
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• 2020

This study was conducted to explore the effect of the type of dashboard on online group discussion activities based on learning analysis. The experimental research was conducted among 51 learners from a university by dividing them into 2 groups. Group A provided participation and interaction dashboard, and group B provided the discussion topics and message type dashboard. First, pre-tests were conducted on attitudes toward computer writing and the level of motivation that could affect online discussion activities. Then the students participated three different topics of online group discussions. The participation and interaction data were automatically collected through the dashboard, and learning outcome data were collected through post-tests. The results showed level of participation in Group B (M=47.56, SD=2.37) that provided discussion topics and message type dashboard was significantly higher than the level of participation in Group A (M=38.13, SD=2.21) that provided participation and interaction dashboard. On the other hand, there were no differences in the level of interaction and learning outcomes. In future studies, we suggest that the dashboard effects based on the learners' characteristics should be carried out because the learners' characteristics may affect the use of the dashboard.

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1399-1408
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• 1999

Geometrical structures for the dimerization of (NO)₂ from (NO + NO) have been calculated using ab initio Har-tree-Fock (SCF), second-order Møller-Plesset perturbation (MP2), and coupled cluster with the single, double, and triple substitution [CCSD(T)] methods with a triple zeta plus polarization (TZP) basis set including diffuse Rydberg basis functions. The structure of (NO)₂ can be described by two interactions (N…N, N…O). One is the ONNO structure with an (N…N) interaction. In this structure, acyclic cis-ONNO with $C_{2v}$-symmetry, acyclic trans-ONNO with $C_{2h}$, and cyclic ONNO with trapezoidal structure ($C_{2v}$) are optimized at the MP2 level. The other structure is the ONON structure with an (N…O) interaction. In the structure, acyclic cis-ONON with Cs$^{-symmetry}$ and cyclic ONON of the rectangular ($C_{2h}$), square $(D_{2h})$, rhombic $(D_{2h})$, and parallelogramic $(D_{2h})$ geometries are also optimized. It is found that acyclic cis-ONNO (¹A₁) is the most stable structure and cyclic ONNO (³A₁) is the least stable. Acyclic trans-ONNO (³A₁) with an (N…N) interaction, acyclic trans-ONON and bicyclic ONON $(C_{2v})$ with (N…O) interaction, and acyclic cis- and trans-NOON with an (O…O) interaction can not be optimized at the MP2 level. Particularly, acyclic trans-ONNO with $C_{2h}$-symmetry can not be optimized at the CCSD(T) level. Meanwhile, acyclic NNOO (¹A₁, $C_s)$ and trianglic NNOO (¹A₁,$C_{2v})$ formed by the (O…N) interaction between O₂ and N₂ are optimized at the MP2 level. The binding energies and the relative energy gaps among the isomers are found to be relatively small./sec. Spiral CT scans during the arterial phase were obtained 35 seconds after the injection of contrast medium. CT findings of 78 lesions less than 4cm in diameter were correlated with angiographic findings. Results : The attenuation of lesions was high(n = 69), iso(n = 5), and low(n = 4) compared with liver parenchyma during the arterial phase of spiral CT. In lesions with high-, iso-, and low-attenuation during the arterial phase of spiral CT, hypervascularity on angiograms was found in 63 of 69(91.3%), three of five(60%), and three of four lesions(75%), respectively. Six lesions with high-attenuation on the arterial phase of spiral CT were not seen on angiography. Two iso-attenuated and one low-attenuated lesion were hypovascular on angiograms. Conclusion : The results of this study suggest that with some exceptions there was good correlation between the arterial phase of spiral CT and angiography.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2555-2562
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• 2010

In this paper, we propose the method that extracts sea level measurements graph from the sea level measurements recording paper image with a little interaction. At first, a pixel that is included in the graph area is selected. Then, background pixels are automatically determined using the distance between a selected pixel and other pixels on LAB color space. In each vertical line, a pixel that is the nearest to the selected pixel on LAB color space is extracted and the graph area is determined using that pixels. Experimental results show that the sea level measurements graph can be extracted with a few interaction from the various sea level measurements recording paper images.

• Journal of Fashion Business
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• v.25 no.4
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• pp.79-91
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• 2021

Currently, chatbot, a conversational platform based on artificial intelligence, is drawing attention as a new marketing channel. This study attempted to verify the effect of the anthropomorphism, message type, and media self-efficacy level on purchase intention. The experimental design of this study was a 2 (anthropomorphism level of shopping chatbot: low vs. high) × 2 (message type: factual vs. evaluative) × 2 (media self-efficacy: low vs. high) three-way mixed analysis of variance (ANOVA). This study conducted a survey by the convenience sampling method of 402 women in their 20s and 30s living in Seoul and the Gyeonggi area who were aware of chatbot services. For the final analysis, 388 questionnaires were used. Data were analyzed with the SPSS 23 program and three-way ANOVA. Simple main effects analysis was conducted. The results of this study were as follows. First, there were statistically significant differences in purchase intention according to anthropomorphism level, message type, and media self-efficacy. Second, message type and media self-efficacy showed statistically significant interaction effects on purchase intention. Lastly, anthropomorphism and the media self-efficacy level and the message type of the shopping chatbots showed significant three-way interaction effects on purchase intention.

• Asia Marketing Journal
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• v.18 no.1
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• pp.37-53
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• 2016

The purpose of this study is to show that the effectiveness of utilitarian versus hedonic attributefocused advertisement on product evaluation depends on the arousal level of positive emotion, and to explore mediation effect of cognitive response to utilitarian attribute-focused advertisement and affective response to hedonic attribute-focused advertisement on the effectiveness of utilitarian versus hedonic attribute-focused advertisement. This research employs a 2 (arousal level: mild vs. elevated) × 2 (advertisement type: utilitarian vs. hedonic) between-subjects design, and 200 undergraduate students participate in the experiment, in which there are 50 students at each experimental group. The results of ANCOVA with positive emotion level as a covariate on advertised product evaluation show significant interaction effect of arousal level and advertisement type, and no effect of positive emotional level. Both of the mediation effects of the cognitive response and those of the affective response are significant. Participants under mild (elevated) arousal of positive emotion more positively evaluate the product in utilitarian (hedonic) attribute-focused advertisement. The positive effect of utilitarian (hedonic) attributefocused advertisement on product evaluation is partially mediated by cognitive (affective) response to the advertisement when consumers are under the mild (elevated) arousal of positive emotion. The results of this study show that advertisers should use utilitarian (hedonic) attribute-focused advertisement to consumers under the mild (elevated) arousal of ambient positive emotion, which should be searched by exploring what kind of event they have experienced.

• Journal of Korea Game Society
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• v.11 no.4
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• pp.37-48
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• 2011

As people increasingly play online games, numerous new features have been proposed to increase players' log-on time at online gaming sites. However, few studies have investigated why people continue to play certain online games. This research would verify that enjoyment experience could be explained by the conceptual framework. In the first, this study results indicate that customers would show a higher level of loyalty if they had an optimal experience with the games. The state of flow was felt when players were aware of opportunities for personal interaction and social interaction. The personal interaction could be motivated either to achieve the high cognitive performance or by providing the equity of distribution of the objective performance in order to examine players' cognitive performance; the social interaction can be motivated either to enhance a high level of self-esteem of player or to achieve the positive reputation in order to evaluate their self-esteem. This finding can answer the questions of what enjoyment experience is and why players are repeatedly playing specific online games.