• 한국산학기술학회논문지
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• 제13권8호
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• pp.3436-3443
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• 2012

본 연구는 사이버학습환경에서 학급공동체의식과 사회적 실재감이 학습만족도에 미치는 영향을 살펴보는데 목적이 있다. 이를 위해 D광역시 M초등학교 6학년 사이버가정학습 학습자 172명을 대상으로 설문조사를 실시하여 데이터를 수집하였으며 학급공동체의식, 사회적 실재감과 학습만족도와의 관계를 알아보기 위해 중다회귀분석을 실시하였다. 연구 결과 학급공동체의식과 사회적 실재감, 학습만족도 간에는 의의 있는 상관관계가 나타났고, 학급공동체 의식이 학습만족도에 영향을 미치는 것으로 나타났다. 이러한 결과는 초등 사이버학습환경에서 학급공동체의식은 학습자의 학습만족도 향상을 위해 중요하게 고려해야 할 변인임을 시사한다. 이에 향후 사이버학습환경을 구성할 때 학급공동체의식을 높이기 위한 교수설계 전략이 요구된다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2008년도 추계학술대회 및 정기총회
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• pp.410-414
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• 2008

Providing recommendations is acknowledged as one of important features of a business-to-consumer online storefront. Though there have been many studies on algorithms and operational procedures of personalized recommender systems, there is still a lack of empirical evidence demonstrating relationships between social presence and two important outcome variables of recommender systems: reuse intention and trust. To test the existence of a causal link between social presence and reuse intention, and mediating role of trust between these two variables, this study performed experiments varying level of social presence while providing personalized recommendations to users based on their explicit preferences. This study also compared these effects in two different product contexts: hedonic and utilitarian product. The results show that the provision of higher social presence increases both the reuse intention and trust of the recommender systems. In addition, the influence of social presence on reuse intention in the setting of recommending utilitarian products is less than that in the setting of recommending hedonic products.

• 유통과학연구
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• 제13권2호
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• pp.75-83
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• 2015

Purpose - This study aims to identify the effects of communication cues, anonymity, and social presence on group polarization in computer-mediated communication (CMC) settings. Extant literature has introduced some theoretical backgrounds of social presence and SIDE (Social Identity model of Deindividuation Effects) to explain the effects of communication cues and anonymity. The concept of social presence emphasized the mediating role on communication cues and anonymity. However, most literature did not measure social presence and compare group polarization of all condition groups. This does not sufficiently explain the result of group polarization. Research design, data, and methodology - We believe that the direct impact of anonymity on group polarization can provide a more admissible and clearer explanation for the results. In addition, this study categorizes anonymity into two levels, as anonymity of group and anonymity of self. To justify the anonymity view, a laboratory experiment was conducted. The experiment was conducted in communication cues settings (visual cue; without visual cue) and anonymity settings (identified; anonymous). Each of the four settings has 10 groups consisting of five subjects each (total 200 subjects). The subjects are undergraduates from a large university, majoring in business. All experimental procedures and calculations of choice shift and preference change follow the literature. Results - First, the removal of visual cues does not produce a significant impact on group polarization, which cannot be explained by the social presence view. Second, the anonymous condition does not significantly affect group polarization, which also cannot be explained by the social presence view. However, the anonymous condition directly affects group polarization. Specifically, anonymity of self has a stronger effect on group polarization than anonymity of group. The result explains about the leading factor affecting group polarization. This study examines another view of how computer-mediated communication may be associated with group polarization. The process and outcome data from the experiment reveal that group polarization is not affected by level of social presence, but by level of anonymity. Group discussions conducted with visual cue CMC setting and identified CMC setting result in weaker group polarization. Conversely, group discussions conducted without visual cue CMC setting and anonymous CMC setting lead to stronger group polarization. The results of the study have the following implications. First, they provide clues for business organizations to design the most appropriate media conditions and preemptive social conditions to implement when making group decisions through CMC, to maximize achievements, generate amicable agreements, or actively share information. Second, this study can be useful in analyzing different adverse effects generated through Internet use. Conclusions - This research can help explain discussions and decision-making actions on Internet forums, which have recently increased, as well as providing a foundational basis in newly establishing policies for the forums. Finally, it should be noted that many other factors such as group size, topics, and group history may affect group polarization. These should be examined in future studies.

• 비파괴검사학회지
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• 제35권6호
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• pp.414-420
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• 2015

Concrete undergoes significant phase changes from liquid to solid states as hydration progresses. These phase changes are known as the setting process. A liquid state concrete is electrically conductive because of the presence of water and ions. However, since the conductive elements in the liquid state of concrete are consumed to produce non-conductive hydration products, the electrical conductivity of hydrating concrete decreases during the setting process. Therefore, the electrical properties of hydrating concrete can be used to monitor the setting process of concrete. In this study, a parameter identification method to estimate electrical parameters such as ohmic resistance of concrete is proposed. The effectiveness of the proposed method for monitoring the setting process of concrete is experimentally validated.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.628-631
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• 2004

In this paper, mechanical properties of concrete incorporating CKD are discussed with W/B and fluidity. For setting properties, an increase in W/B retarded setting time greatly in $5^{\circ}C$, while accelerated in $20^{\circ}C$. For fluidity, an increase in slump delayed the setting time with dosage of SP agent. The presence of CKD has little influence on setting time compared with plain concrete. For compressive strength, an increase in maturity enhanced compressive strength. Fluidity had no relation to compressive strength. At low curing temperature, concrete with CKD has slight strength loss compared with plain concrete. However, remarkable strength loss at low curing temperature in early stage was not found, which can be applicable to low temperature environment concrete placing.

• ETRI Journal
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• 제32권5호
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• pp.687-694
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• 2010

Breaks in presence (BIP) are those moments during virtual environment (VE) exposure in which participants become aware of their real world setting and their sense of presence in the VE becomes disrupted. In this study, we investigate participants' experience when they encounter technical anomalies during game play. We induced four technical anomalies and compared the BIP responses of a navigation mode game to that of a combat mode game. In our analysis, we applied a linear mixed model (LMM) and compared the results with those of a conventional regression model. Results indicate that participants felt varied levels of impact and recovery when experiencing the various technical anomalies. The impact of BIPs was clearly affected by the game mode, whereas recovery appears to be independent of game mode. The results obtained using the LMM did not differ significantly from those obtained using the general regression model; however, it was shown that treatment effects could be improved by consideration of random effects in the regression model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.220-222
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• 2001

This paper represents impedance calculation of the distance relay using PSCAD/EMTDC software for transmission line involving the UPFC (Unified Power Flow Controller) device, which is the most vigorous component of FACTS. The presence of the UPFC significantly affects the line parameters of transmission system, which are also influenced by the distance relay setting. Moreover depending on the UPFC location and its parameters, zones of setting the distance relay will be changed. The presence of the UPFC in the fault loop affects both voltage and current seen by relay. Therefore, the distance relay should be taken into account the variable injected voltage of the UPFC.

• 한국염색가공학회지
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• 제2권2호
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• pp.14-19
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• 1990

The setting behavior of disulfide-enriched wool and disulfide-crosslinked silk obtained by treatment with a disulfide-containing crosslinking agent, bis $(\beta-isocyanatoethyl)$ dissulfide was compared with that of untreated wool and silk under the absence and the presence of a reducing agent. Rearrangment of secondary bonds facilitated by cleavage of crosslinks as well as rearrangement of crosslinks itself seems to play an important role in the set stability.

• International Journal of Contents
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• 제16권4호
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• pp.39-49
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• 2020

The goal of this research was to understand the patterns of multidimensional engagement in MOOCs. An email with an online survey link was sent to enrollees in an MOOC course. The survey included 35 questions asking about engagement, teaching presence, and learning persistence. The items were validated in the literature, revised for the MOOC setting, reviewed by four professionals in the field of educational technology, and used in the study. A heterogeneous group of 170 individuals gathered through convenience sampling participated in the study. With cluster analysis of the engagement data, three groups were identified: Cluster1, 2, and 3. Cluster 1 scored high on behavioral, emotional, and cognitive engagement. Cluster 2 scored high on behavioral aspects but low on emotional and cognitive engagement. Cluster 3 scored low on behavioral and cognitive engagement but high on emotional aspects. The study addressed cluster-specific learner characteristics and differences in perceived teaching presence and learning persistence. Design strategies pertaining to each cluster were further discussed. These strategies may guide instructors and practitioners in the design and management of MOOCs and should be further validated through future studies.

• 한국미생물·생명공학회지
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• 제45권4호
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• pp.354-357
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• 2017

There is an increase in the presence of drug-resistant staphylococci outside of the nosocomial and healthcare setting. Although the presence of staphylococci has been studied in several public spaces, nothing is known on the presence of staphylococci in public libraries. Book surfaces from public libraries in the East London area, United Kingdom were swabbed and cultured and identity of the isolates determined by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS). Seven different staphylococcal species were identified by MALDI-TOF-MS analysis. This short study provides evidence of the presence of multidrug-resistant staphylococci in public libraries in the East London area.