• 대한수학회보
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• 제58권5호
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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.

• Asia pacific journal of information systems
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• 제18권1호
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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.

• 과학교육연구지
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• 제33권2호
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• pp.193-206
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• 2009

본 연구의 목적은 지구의 운동 관련 개념을 연속적으로 학습하는 과정 속에서 중학생들에게 지구 자전축의 기울기가 일관되게 묘사된 삽화들의 제시가 지구의 자전, 공전에 따른 계절변화, 별자리 변화 등 관련 개념 습득 및 파지에 미치는 영향을 알아보는 것이다. 이를 위해 중학교 1학년 학생 116명을 대상으로 이질통제집단 사전사후검사 설계를 하였다. 실험집단(n=59)과 통제집단(n=57) 모두 3차시 동안 동일한 내용과 교수방법으로 교수-학습활동을 전개하였으며 실험집단에는 자전축의 기울기 방향이 동일한 삽화들을 제공하였다. 학습 종료 2일 후, 습득된 개념의 두 집단 간 차이를 확인하기 위해 ANCOVA 테스트로 1차 사후검사를 실시하여 비교하였다. 그 결과, 자전축 기울기가 일관되게 표현된 삽화를 제시하였을 경우에 학습의 효과가 더 큰 것으로 나타났다. 1차 사후 검사에서 실험집단과 통제집단이 습득한 개념들의 파지정도를 비교하기 위해, 2달 후 2차 사후검사를 대응표본 t-test를 실시하였다. 그 결과, 실험집단에서는 1차 사후 검사 점수와 2차 사후 검사 점수의 평균 차이가 유의하지 않은 것으로 나타나 개념의 파지에도 긍정적인 효과가 있는 것으로 확인되었다. 반면, 통제집단에서는 평균의 차이가 유의미하게 나타나 개념의 파지에 부정적인 것으로 확인되었다. 따라서 천문 개념을 학습하는데 있어서 학생들에게 유의미한 학습이 되기 위해 일관된 삽화를 사용하는 세심한 배려가 필요하다고 본다.

• 한국과학교육학회지
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• 제18권1호
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• pp.83-92
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• 1998

본 연구에서는 제한물질을 포함하고 있는 화학양론에 관한 개념 회상 및 응용에 미치는 비유물의 체계성과 표현 방식의 효과를 조사하였다. 체계성은 인과 구조를 어느 정도 명확하게 포함하느냐에 따라 구분하였고 표현 방식은 언어 형태와 언어와 그림 양 형태로 구성하였다. 137명의 중학생들에게 네 가지 유형의 비유물을 무선 배치하고 이를 학습하도록 하였다. 처치 이전에 Group Assessment of Logical Thinking 검사를 실시하고 그 점수를 공변인으로 사용하였다. 처치 이후에 연구자가 제작한 개념 검사를 바로 실시하고 4주 후에 파지 검사를 실시하였다. ANCOVA 분석 결과 체계성은 표현 방식에 관계없이 학습 직후 개념 응용에 긍정적인 영향을 미쳤다. 그러나 파지 검사의 개념 응용 문제에서는 체계성에 따른 주효과는 없고 표현 방식과의 상호작용 효과가 있었다. 이러한 결과는 언어와 그림 양 형태로 제작한 체계적인 비유물이 개념 응용에 가장 효과적임을 나타낸다. 이에 대한 교육학적 합의를 논의하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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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.

• 한국환경교육학회지:환경교육
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• 제19권2호
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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.

• 지역사회간호학회지
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• 제18권1호
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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.

• 대한정형도수물리치료학회지
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• 제18권2호
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• pp.31-39
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• 2012

Background: The purpose of this study was to develop a problem-based learning model for orthopedic manual physical therapy. A problem-based learning (PBL) model for orthopedic manual physical therapy developed from PBL module of Jeju C university (Halla-Newcastle PBL Center). A summary of this study is as follows: 1) PBL model is comprised of a class of 30 students, operated small group as of 4~5 students. 2) PBL is suggested a scenario of clinical case, induced variety reaction through group discussion and presentation. 3) PBL is occurred wide variety learning through group work activity and self-directed learning. 4) The tutor as a facilitator is played a guide for group discussion, work activity and team learning. 5) The evaluation for PBL is performed such as student self-evaluation, group activity evaluation, individual presentation, and practice. This model is considered wide variety learning through team learning and self-directed learning by clinical reasoning and problem solving for musculoskeletal clinical case. We suggest problem based learning for the education of orthopedic manual physical therapy in which the learners are very interested in and has the effective outcome.

• 한국정보시스템학회지:정보시스템연구
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• 제17권3호
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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.

• 복식문화연구
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• 제29권3호
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• pp.346-360
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• 2021

Universities have recently introduced problem-based learning (PBL) to various subjects to enhance problem-solving skills (including self-directed learning and small-group learning) required in industry. The PBL module was applied to the personal production process in a draping class. A study was based on a questionnaire after conducting two PBL modules with a group of students. Each PBL module included 'design analysis', 'presentation of flat sketch and draping plan', 'discussion of the plan', 'evaluation of the draping result and correcting the problem', and 'final evaluation of the completed project'. Results showed that satisfaction with the PBL method and its activities was higher than satisfaction with existing teaching methods. In particular, among the various components, the 'design analysis' and 'the presentation step of flat sketch and draping plan' stages were more helpful to students compared to small-group discussion. Moreover, the effects of PBL were observed through student reflection essays, in which students suggested that PBL was very effective in enhancing problem-solving through self-directed and small-group learning. Despite the overall satisfaction with PBL, students expressed some minor difficulties associated with awkwardness with a novel learning method, lack of diverse perspectives among each group, and poor communication skills. Therefore, the study shows that PBL is highly likely to be useful to students when they are solving pattern drafting problems and making samples through self-directed learning and small-group learning.