• Bulletin of the Korean Mathematical Society
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• v.58 no.5
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• pp.1301-1314
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• 2021

In this paper, firstly, we work on the presentation of the crossed product of groups of general types. After that we find the generating pictures (Second Homotopy Group) of this product by looking the relations from a geometric viewpoint. Finally, we give some applications.

• Hwankyungkyoyuk
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• v.19 no.2 s.30
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• pp.133-146
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• 2006

The purpose of this study was to examine how environmental education teachers think about environmental teaching materials of their use in primary and secondary schools. For this purpose, six primary and secondary school teachers were selected for focus group discussion on October 17th, 2005. The discussion of focus group was recorded both on video and audio tapes. Teachers' discussion could be analyzed in the perspectives of two big ideas, 'content selection' and 'content organization and presentation'. The big ideas were categorized into several areas: 1) The idea of 'content selection' was classified into 4 areas such as integration, difficulty level, locality, and timeliness, 2) The idea of 'content organization and presentation' was classified into 4 areas such as learning motivation, teaching and teaming strategy, evaluation method, application of teaching materials. This study provided meaningful ideas, which can be used in developing environmental education materials as well as effective teaching and teaming strategies for school environmental educators.

• Journal of Science Education
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• v.33 no.2
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• pp.193-206
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• 2009

The purpose of this study was to examine the effect of the consistent presentation of illustrations about the aligning direction of the Axis on the middle school students' acquisition and retention of astronomical concepts. This study was taken using the nonequivalent control-group pretest-posttest design on 116 7th middle school subjects. The same teaching and learning activities were given to both the experimental (n=59) and control groups (n=57) through three lessons. The experimental group was given a consistent presentation of the illustrations about the aligning direction of the Axis, while the control group was given an inconsistent presentation of the same illustrations about aligning direction. Two days after the three lessons, the 1st posttest was administered to compare the statistical difference of mean of both groups, using ANCOVA test. The result of ANCOVA test implicated that the consistent presentation of the illustrations about the aligning direction of the Axis had a positive influence on the experimental group's acquisition of the concepts. The 2nd posttest result for retention effect was given two month later by one-paired t-Test in each group and showed that the method had a positive effect on the experimental group, compared with control group. The results of this study implicated that paying careful attention to using the consistent illustration is highly beneficial for students' meaningful learning on astronomical concepts.

• Journal of The Korean Association For Science Education
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• v.18 no.1
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• pp.83-92
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• 1998

This study investigated the effect of systematicity and presentation type of an analog upon students' concept recall and application regarding stoichiometry that included limiting reagent. Systematicity was manipulated by varing the degree of explicit causal structure, and presentation type was in either verbal format or verbal/figurative format. The four types of the analog developed were studied by randomly assigned junior high school students (N=137). Prior to the treatment, the Group Assessment of Logical Thinking was administered and its score was used as a covariate. After the treatment, a research-made conception test was administered immediately and four weeks later. The ANCOVA results indicated that systematicity had a positive effect on immediate application regardless of presentation type. In the application problem of retention test, however, systematicity had no main effect but interaction with presentation type. These suggested that the systematic analog in verbal/figurative format most positively influence concept application. Educational implications are discussed.

• The Journal of Information Systems
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• v.17 no.3
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• pp.79-109
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• 2008

Cyworld was successful where others have foiled because of its unique and profitable business model that relies on the purchase of digital items and its ability to mimic and recreate aspects of face-to-face interpersonal relationships among the members of the online community. The purpose of this study is to understand how the needs for self-presentation and needs for affiliation influence digital item purchase intention, and to analyze the moderating roles of gender and purchase experience in those relationships. Based on the theoretical framework including self-presentation theory and theory of affiliation, we developed the research model and proposed ten hypotheses. A survey was conducted with 225 members of Cyworld. The research model and the related hypotheses were tested using Amos. As the result of the analysis, eight hypotheses out of ten hypotheses were supported. In particular, digital item purchase intention in virtual world was found to be affected by both members' needs for self-presentation and needs for affiliation. We also found that the needs for self-presentation is significantly influenced by innovativeness of members, self-efficacy, and group norm. Also, needs for affiliation is significantly affected by self-efficacy, group norm and perceived value. Furthermore, the results indicate that 1) moderating effects of gender on those relationship is supported; and 2) moderating effects of purchase experience is partially identified. This study provides several implications for academic community and practitioners to understand why the community members pay real money for their digital items as well as how the sales of digital items can be increased in online communities. Some study limitations and future research directions are also discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.641-649
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• 2020

This study was conducted to examine the effects of instruction (explicit, implicit) and stimulus presentation time (300 ms, 500 ms) in ABM training. According to the Social Avoidance and Distress Scale (SADS) and the attention bias score (ABS), 60 undergraduate students were selected. All participants' SADS scores were above 82 and their ABS score was greater than 0. The training group was explicit-300 ms training group (n=10), explicit-500 ms training group (n=10), implicit-300 ms training group (n=10) and implicit-500 ms training group (n=10). In the implicit instruction group, only information about procedure was included. In the explicit instruction group, additional information about training manipulation (the probe always presented at the location of the preceding neutral stimuli) was provided. The control group were placebo-300 ms control group(n=10) and placebo-500 ms control group(n=10). After 8 sessions of training, the effect was only found in instruction conditions. The explicit training group showed significantly decreased SADS after training. ABS changed significantly in all three conditions but the treatment effect was most effective in the explicit instruction condition. No significant effect was found in the stimulus presentation time. These results suggest that explicit instruction might promote the effect of ABM training compared to implicit instruction.

• Asia pacific journal of information systems
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• v.18 no.1
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• pp.117-144
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• 2008

Lots of virtual communities and online businesses presently derive their primary sources of revenues through advertising, but nevertheless are plagued with marginal profitability though they might possess a significant user base. In the light of the need for an efficacious business model, there have been recent insights of an online community in particular reaping profits through an innovative and lucrative revenue generation method that earns by selling digital items. There have been some obvious evidences (e.g., Cyworld, SecondLife, Habo Hotel, etc.) that online communities can be profitable through their unique business model of selling digital items. However, there is lack of understanding about the motivation of purchasing digital items. This study tries to identify the main motivators of digital item purchases based on social/individual identity theory and self-presentation theory. "Digital items", otherwise known as "virtual assets", may include online avatars, accessories for the avatars, decorative ornaments like furniture, digital wallpapers, skins, background music and virtual weapons used for Internet games. These digital items are employed by users for representation and articulation in the online space, especially to create and enhance their online profiles in web pages and games. Prices for digital items typically range from a few cents to a few dollars each. Based on the theoretical framework like social identity theory and self-presentation theory, we developed the research model and proposed seven hypotheses. An analysis of 225 members of Cyworld found that digital item purchase intention in virtual world is affected by both members' need for self-presentation and need for affiliation. We also found that the need for self-presentation is significantly increased by innovativeness of members, community group norm, and community involvement. We concluded that the need for self-presentation could be a key variable for profitable business model in online community service industry. However, neither individual self-efficacy nor the need for affiliation significantly influenced the need for self-presentation which triggers purchase intention of digital items. In term of the theoretical and practical contribution, this study can be a pioneering empirical research that investigates the purchase intention of digital items based on social identity theory and self-presentation theory in the online context. Also, the findings of our study are valuable and practical for practitioners in the market who wish to adopt or improve the business model of selling digital items in an online community. From the findings, it can be seen that innovativeness of users, community group norm, and community involvement are three significant factors that influence need for self-presentation of users which ultimately leads to their intentions to buy digital items. These findings put forth that virtual community providers and online businesses selling digital items should prioritize their efforts and focus on these three factors if they want to increase the sales of these digital items and generate greater revenues. This study provides important implications for academic researchers and practitioners to understand why the community members pay money for their digital items in virtual world and how the practitioners can increase the sales of digital items in an online community. A couple of limitations of the study and future research directions are also discussed.

• Research in Community and Public Health Nursing
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• v.18 no.1
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• pp.156-164
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• 2007

Purpose: This study was to investigate adequate strategies of PBL in community health nursing for learning in the real community situation. Method: Data were collected in a PBL class of 14 third-year students who solved problems and assessed PBL in community health nursing related to visiting nursing and chronic diseases. Results: The students guessed situations diversely, chose learning issues widely and mapped the learning concepts specifically. In the assessment of the presentation, the peers of the same group gave the highest score $29.00{\pm}3.36$, the tutor lowest score $22.83{\pm}5.15$. In 5-point Likerts scale, the group dynamic was highest ($4.18{\pm}.61$) and the presentation was lowest ($3.59{\pm}.84$). Conclusion: The group needs to include students who have experiences in the practice at the health centers. The PBL class should be managed by the block system along with the conventional learning. Students needs to practice the self-directed learning and the presentation in a first semester and then PBL. The introduction of community health nursing begins with the conventional lecture and the programs on life circle and health centers through PBL in the comprehensive curriculums.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.13-13
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• 2011

Graphene based nano-electronic and nano-electromechanical devices will be introduced in this presentation. The first part of the presentation will be covered by our recent results on the fabrication and physical properties of artificially twisted bilayer graphene. Thanks to the recently developed contact transfer printing method, a single layer graphene sheet is stacked on various substrates/nano-structures in a controlled manner for fabricating e.g. a suspended graphene device, and single-bilayer hybrid junction. The Raman and electrical transport results of the artificially twisted bilayer indicates the decoupling of the two graphene sheets. The graphene based electromechanical devices will be presented in the second part of the presentation. Carbon nanotube based nanorelay and A new concept of non-volatile memory based on the carbon nanotube field effect transistor together with microelectromechanical switch will be briefly introduced at first. Recent progress on the graphene based nano structures of our group will be presented. The array of graphene resonators was fabricated and their mechanical resonance properties are discussed. A novel device structures using carbon nanotube field effect transistor combined with suspended graphene gate will be introduced in the end of this presentation.

• Communications of the Korean Mathematical Society
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• v.27 no.4
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• pp.653-664
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• 2012

We study the abstract structure of the automorphism group of the ternary self-dual code of length 8 and give its convenient presentation by generators.