• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.88-95
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• 2001

Silicon nitride based ceramics reinforced with 3wt% Si$_{3}$N$_{4}$ whisker was prepared by tape casting to investigate the effect of microstructure on erosion behaviors. Hardness and fracture toughness were measured with prepared specimens. A gas blast type erosion tester was used to examine the erosion behavior of the specimens with different impact directions and angles. The erosion rate increases with increasing impact angle. Erosion rate of the silicon nitride ceramics also depends on the grain orientations, The erosion rate was lowered when impaction direction was parallel to the grain orientation This result was explained by the crack deflection and bridging due to the grain orientation.

• International Journal of Automotive Technology
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• v.5 no.1
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• pp.23-31
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• 2004

Secondary movements of piston in the bore clearance are closely related to the side impact to the engine block as well as many tribological problems. Some of the major parameters that influence these kinds of movements are piston profile shapes (barrel and flat), piston pin offsets and the magnitudes of bore clearances. In our study, computational investigations are performed about the piston movements in the bore clearance by changing the skirt profiles and piston offsets. In this work, it is found that curved profile and larger offset magnitude to thrust side provide better performance that has low side impact during the engine cycle.

• Management & Information Systems Review
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• v.26
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• pp.231-259
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• 2008

Recently, almost of the colleges are contrive measures to satisfy the needs of students. The purpose of this study is to find what are the impact factors to the needs of those. To evaluate the factors influencing to students behaviors, it was investigated how much did the 5 variety of Service quality-Tangibles, Assurance, Responsiveness, Empathy, Reliability-and 4 variety of attitude models to depending to the level of students influence the satisfaction of students for the students of W college. In the result, this study shows that 5 variety of Service quality did not impact for the general service quality, but only the Responsiveness and, Empathy have the positive relationship to the satisfaction of students. Also, general service quality and attitude willingness have the positive correlation with the satisfaction of students. And it is investigated that there are significance differences among the general service qualities by the level of students ability.

• Steel and Composite Structures
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• v.17 no.6
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• pp.825-834
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• 2014

This manuscript presents an experimental investigation on the effect of Multi-walled carbon nanotubes (MWCNTs) addition on the tensile, flexural and impact properties of woven Kevlar fabric reinforced epoxy composites. MWCNTs were dispersed in the epoxy resin by sonication technique and the samples were fabricated by hand layup laminating procedure. Scanning electron microscopy (SEM) was used to characterize the microstructure of produced samples. The effects of adding small amounts (${\leq}1%$) of MWCNT on the tensile, flexural and impact (Izod) behaviors of laminated composites were analyzed. Results revealed that MWCNTs enhanced the Young's modulus up to 20%, bending modulus up to 40%, and impact strength up to 45% in comparison with woven Kevlar fabric/epoxy composites. It was found that the maximum improvements in mechanical properties were happened for 0.5 wt.% MWCNT.

• Journal of Auto-vehicle Safety Association
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• v.12 no.1
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• pp.39-45
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• 2020

The express/intercity bus models have been developing for wheelchair users to provide the preferable long-distance travels by the Korean government research. In the previous studies, evaluation method was set up for the wheelchair users' safety and the study for wheelchair occupants' safety was performed under various crash loadings mimic to real accidents, frontal crash, side impact and rollover, etc. This study was focused on the evaluation of occupant behaviors and injuries (head and chest) during vehicle impact loading cases in order to ensure the safety of wheelchair passengers in the bus. The occupant response and belt loading data during the sled FE simulation were compared with those of the sled test. The simulation results showed overall safety tolerances of wheelchair occupants under the severe frontal deceleration, side impact loading based on the FMVSS 214 configuration and bus rollover loading.

• Journal of the Korean Society of Safety
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• v.10 no.2
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• pp.64-71
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• 1995

Tests were performed to evaluate the effect of thermal shock behavior on the mechanical properties of PC(poly-carbonate) and PET(polyethylene-terephthalate) with MBS(methylmethacrylate-butadiene-styrene) alloy. Five different material weight fraction for PC/PET were employed : 0/100, 25/75, 50/50, 75/25, and 100/0. Three different weight fraction of MBS were added to each PC/PET : 0, 3, and 9. Therefore fifteen different types of PC/PET/MBS were prepared using single screw extrude. and injection molding machine. One thermal shock cycle consisted of each one hour stay at -$40^{\circ}C$ chamber and $＋80^{\circ}C$ chamber without delay. Specimens were thermal shocked up to 20 and 40 cycles. Specific mechanical properities considered in this study include tensile, izod impact, and high rate Impact behaviors. In addition, the morphology of the fractured surface after Izod impact testing was investigated by the SEM (scanning electron microscope).

• Journal of Information Technology Applications and Management
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• v.27 no.6
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• pp.31-51
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• 2020

During the last decade, social live streaming service like Periscope, Ustream, and YouNow has developed from a niche market into a mainstream activity. In this media environment, social live streaming service has a tremendous impact on the social behaviors of users. Despite the rapid development, there are a lack of studies to make better understand the media environment changes through social live streaming service. This study adopted an affordances approach that leads us to identify six distinctive social affordances (visibility, accessibility, information sharing, social interaction, role-taking, interactive revenue) for user engagement in social live streaming service. Specifically, this study explores the impact of social affordances on perceived flow, followed by user engagement including passive and active engagement. Empirical data analysis with 258 questionnaires suggests that social affordances affected users' flow perception, and flow has an effect on active as well as passive engagement. Contrary to the expectation in a hypothesized research model, only the impact of accessibility on flow was rejected.

• Science of Emotion and Sensibility
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• v.26 no.2
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• pp.3-12
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• 2023

The present study examines the impact of COVID-19 anxiety on employees' psychological resources and behaviors, drawing on the conservation of resources theory. We also investigate whether flexibility in work contexts has a meaningful effect on employees' responses to the pandemic. A total of 284 working adults participated in an online survey consisting of self-reporting questionnaires that assessed levels of COVID-19 anxiety, vigor, innovative work behavior, and flexible working arrangements. The results showed that the level of vigor mediated the positive relationship between COVID-19 anxiety and innovative work behavior, and the perceived level of flexible working arrangements moderated this mediation effect positively. The findings highlight the importance of considering employees' psychological resources and work arrangements in managing the negative impact of COVID-19-related anxiety. This study provides theoretical and practical implications for organizations to better understand the psychological processes that employees undergo during a crisis. Further research on diverse work settings and cultural backgrounds is needed to expand on the present findings.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.1-16
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• 2023

Influencer advertising, which has gained significant attention in academia and industry, is widely adopted as a digital marketing strategy. This study empirically analyzes the impact of perceived influencer channel attributes and ad attributes on the suitability of advertisements and their effects on consumers' positive and negative advertising behaviors. The research aims to identify various factors that can enhance the effectiveness of influencer advertising. The results reveal that among the influencer channel attributes, informativeness and intimacy have a positive impact on ad suitability, while ad clutter has a negative impact. Additionally, ad-influencer fit positively affect ad attention and negatively influences ad avoidance. Based on these findings, companies can enhance the effectiveness of influencer advertising by first selecting influencers who align well with the advertisement and emphasizing informativeness and emotional bonding to improve ad suitability. Moreover, the study suggests that influencer advertising strategies can be effective as long as they avoid excessive ad clutter, as it diminishes ad suitability. Marketing practitioners and advertising planners can utilize these insights to formulate more effective influencer advertising strategies.

• Journal of the Korean Society of School Health
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• v.37 no.1
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• pp.1-11
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• 2024

Purpose: The purpose of the study was to conduct a descriptive survey to examine the knowledge, infection prevention behaviors, and health beliefs regarding COVID-19 and to identify factors that influence infection prevention behaviors in elementary and middle school students based on the Health Belief Model. Methods: The study included 388 elementary and middle school students in Seoul, Gyeonggi, and Jeonbuk provinces. Data were collected from September 1 to September 15, 2023. The questionnaire consisted of 10 questions about COVID-19 knowledge, 13 questions about infection prevention behaviors, and 15 questions about health beliefs. The collected data were subjected to multiple hierarchical regression analyses. The cronbach's α of infection prevention behaviors was 0.83, the KR-20 of COVID-19 related knowledge was 0.68, and the Cronbach's α of COVID-19 related health beliefs was 0. 78. Results: In Model 1, females showed higher levels of infection prevention behaviors than males (β=.14, p=.006) and middle school students showed lower levels of infection prevention behaviors than elementary school students (β=-.10, p=.037). In Model 2, among COVID-19-related health beliefs, barriers had a significant negative effect on infection prevention behaviors (β=-.20, p<.001) and cues to action had a significant positive effect on infection prevention behaviors (β=.14, p=.037), indicating that lower barriers and higher cues to action were associated with higher levels of infection prevention behaviors. Conclusion: The results showed that prevention behaviors were associated with lower barriers and higher cues to action among COVID-19 health beliefs. Elementary and middle school students in Korea spend a lot of time in groups at private academies or school, which are closed spaces with poor ventilation, making them vulnerable to new infectious diseases such as COVID-19. Unlike adults, infectious diseases can have serious impact on their mental and social health. Therefore, it is necessary for schools to provide accurate and timely health education about COVID-19 to increase cues to action for elementary and middle school students in order to improve their infection prevention behaviors.