• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.6
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• pp.60-65
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• 2021

In this paper, we examined the ignition possibility of the propellant depending on its non-uniform composition of aluminum. Impact and friction sensitivity was investigated by arbitrarily changing the aluminum content in the range of 14~20% to simulate the non-uniform distribution of aluminum in the propellant. As a result of measuring the impact sensitivity, the 50% ignition energy and minimum ignition energy have values around 50 J regardless of the aluminum content. This means that the propellant does not become sensitive to impact even if the aluminum content is increased. On the other hand, the friction sensitivity result shows that as the aluminum content increases, the 50% ignition force and minimum ignition forces were decreased, and thus the propellant becomes sensitive. "Hot Spot" model of propellant ignition is applied, the space inside the propellant is momentarily compressed and ignited by friction stimuli rather than by impact stimuli.

• The Journal of the Korea Contents Association
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• v.20 no.4
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• pp.648-657
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• 2020

This study is a descriptive investigation into the relationship between the degree of the reality shock and the self-efficacy, social support, and ego-resilience of nursing students and the factors that influence their reality shock. The study shows that self-efficacy, social support, and ego-resilience are related with reality shock. The regression analysis shows that self-efficacy, social support, and ego-resilience account for 27.1% of the reality shock. The research results verify self-efficacy, social support, and ego-resilience as factors that influence reality shock. So, it is necessary to develop programs and explore support plans that take into account self-efficacy, social support, and ego-resilience with the aim of relieving the nursing students reality shock. Looking ahead, further studies need to be conducted with expanded objects of investigation with the aim of drawing more attention to the reality shock of nursing students and generalizing research results.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.245-253
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• 2023

The purpose of this study was to investigate the effect of pre-service early childhood teachers' reality shock and school burnout on career search self-efficacy. The study participants were 195 pre-service early childhood teachers. The results of the study were as follows: First, it was found that pre-service early childhood teachers had relatively high level of reality shock, school burnout, and career search self-efficacy. Second, there was a significant positive correlation between reality shock and school burnout and negative correlation between reality shock, school burnout, and career search self-efficacy of pre-service early childhood teachers. Third, pre-service early childhood teachers' reality shock and school burnout significantly influenced career search self-efficacy. The result of this study provides educational basic data on an early childhood teacher training program in improving career search self-efficacy.

• Korean Journal of Culture and Social Issue
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• v.21 no.1
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• pp.45-66
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• 2015

This study explored the moderating effects of social supports (family support, home friends support, foreign friends support) and cultural identity (home identity, foreign identity) on the relationships of reverse culture shock and subjective well-being. Participants were 157 returnees who left home-country prior to the age of 19 and resided in the foreign-country for more than three years. The results of hierarchical regression analyses on two-way interaction effect between reverse culture shock and each hypothesized moderator (e.g., family support, home friends support, foreign friends support, home identity, foreign identity) indicated that reverse cultural shock and subjective well-being was negatively related and their relationship was moderated only by family support. Specifically, the relationship between reverse culture shock and subjective well-being was weaker when the level of family support was higher. Subsequently, three-way interaction among reverse culture shock, one of the social support factors, and one of the cultural identity factors was investigated using hierarchical regression analyses. The results showed that the three-way interaction among reverse culture shock, family support, and home identity was significant. The slope difference tests yielded that the relationship between reverse culture shock and subjective well-being was stronger when both levels of family support and home identity were lower compared to when either level of family support or home identity was higher. These results imply that environmental factors such as family support and intrapsychic factor such as home identity might function as a buffer against the negative consequences of reverse culture shock experience.

• Fire Science and Engineering
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• v.24 no.5
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• pp.102-106
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• 2010

This paper studied the measurement about the gunpowder residue quantity by using a handgun and we carried out an experiment ignition characteristics of the gunpowder residue for the investigation fire cause into the indoor shooting range in Busan. The measurement of the gunpowder residue quantity is spouted by using a 0.38 inch gun and 9 mm gun. We were carried out evaluation experiments such as impact sensitivity test, static electricity sensitivity test, friction sensitivity test and measuring a flash point for the ignition characteristics about the gunpowder residue. From experiment results, the impact sensitivity and friction sensitivity of the gunpowder residue in comparison with ball powder are highly sensitive and the gunpowder residue ignites at a relatively low temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.317-324
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• 2017

The purpose of this study was to identify the effects of social support and self-efficacy on the relationship between the nursing work environment and reality shock among new graduate nurses. The participants were 260 nurses who had worked for less than 1 year at 3 general hospitals and 2 university hospitals, and who were examined from 15 June to 31 August 2015. The data were analyzed by descriptive statistics, simple regression analysis and moderated regression analysis with the SPSS WIN 21.0 program. In the results, the mean scores of the nursing work environment, reality shock, social support and self-efficacy were $3.06{\pm}.313$, $2.73{\pm}.401$, $3.90{\pm}.623$ and $3.73{\pm}.519$, respectively. Social support (F=16.744, p<.001) and self-efficacy (F=40.616, p<.001) had a direct influence on reality shock. Social support (F=7.743, p<.001) and self-efficacy (F=14.676, p<.001) also had a moderating effect on the relationship between nursing work environment and reality shock. Thus, we need to develop a preceptor education standardization and customized mentor program to enhance social support and self-efficacy, which can reduce new graduate nurses' reality shock in the nursing work environment.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.5
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• pp.349-357
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• 2015

The piezoelectric paint sensor is a paint type sensor comprising of an epoxy and piezoelectric powder, which is the main component of a piezoelectric material. This sensor can be easily attached to any type of structure as compared to other sensors because it is viable to directly apply it on structures, as in the case with a typical paint. In this study, the capability of piezoelectric paint sensor for impact detection was evaluated. In Particular, the applications of the piezoelectric paint sensor for railroad vehicles were considered. There have been various cases reported about the damages caused by flying gravel to the under-cover of the railroad vehicle during operation. In order to prevent this, real-time monitoring of the large under-cover surface of the railroad vehicle is unavoidable. Under the assumption of vehicle application, sensor sensitivities were measured after multiple and prolonged exposure to thermal cycle environment $-20{\sim}60^{\circ}C$). Sensitivity evaluation of paint sensor under environmental conditions was conducted in an aluminum specimen. In results, despite the small variations in sensitivity, we could confirm the applicability of this paint sensor for impact detection even after a severe environmental exposure test.

• Korean Journal of Childcare and Education
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• v.11 no.5
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• pp.333-353
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• 2015

The purpose of this study is to find out if individual variables, ego resilience, self-efficacy, and perfectionism of pre-service daycare teachers can predict anxiety about reality shock after being daycare teachers. Subjects were 176 college students in their 1st~4th year who wanted to become daycare teachers. The data were verified by using t-test, ANOVA, Pearson correlation analysis, and hierarchical regression analysis. The study results are as follows: First, the higher the year of school they were in, the higher the anxiety about reality shock was. Second, there was a significant correlation among ego resilience, self-efficacy, perfectionism, and anxiety about reality shock. Specifically, as ego resilience and self-efficacy are lower and perfectionism is stronger, anxiety about reality shock was found to be higher. Finally, the year of school, self-efficacy, and perfectionism of pre-service teacher turned to be variables predicting anxiety about reality shock. Based on the results of this study, we searched for a solution to reduce anxiety about reality shock of pre-service daycare teachers and provide basic information that can do properly prepare future teachers.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.04a
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• pp.481-486
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• 2010

본 논문은 실내사격장 화재 원인에 대한 조사를 위하여 권총 사용에 따른 화약잔사 양에 대한 실측 및 발화특성에 관하여 연구하였다. 화약잔사 양의 실측은 1차로 사대 부분을 밀폐한 상태에서 실내사격장에 사용되는 권총과 동일한 구경 0.38인치 권총 및 구경 9mm 권총을 5발 발사하여 총구 및 약실로 분출되는 화약잔사의 양을 측정하였으며, 2차로 사대 개방 후, 구경 0.38인치 권총을 100발 발사하는 경우, 사대 바닥면에 떨어지는 화약잔사의 양을 측정하였다. 화약잔사에 대한 발화특성은 충격 감도, 정전기 감도, 마찰 감도 및 발화점 시험을 실시하였으며, 비교 평가에는 권총에 일반적으로 사용되는 사용전의 화약(ball powder)을 이용하여 화약잔사와 동일한 시험을 실시하였다. 실험결과 충격감도 및 마찰강도는 화약잔사에서 다소 높게 측정되었으며, 발화점 시험에서는 화약잔사가 비교대상인 사용전의 화약에 비해 낮은 온도에서 발화되는 특성을 나타내었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.11a
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• pp.22-25
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• 2022

본 논문에서는 인공적인 가상 환경에서 사실적인 충격응답을 제공할 수 있는 방법을 모색하기 위한 첫 단계로서 실제 청취 공간에서 충격응답을 획득하고 장애물이 존재할 때 그 충격응답이 어떻게 변화하는지 살펴보기 위하여 충격응답 변화 실측에 대한 실험 결과를 제시한다. 실험은 일상적인 공간으로서 한국전자통신연구원의 회의실과 휴게실에서 수행하였으며, 실험 결과 장애물의 존재에 따라 그리고 청취 위치에 따라 주파수 영역에서 차이점이 발생하는 것을 확인할 수 있었다. 향후 흡음률 등 장애물에 대한 물리적 정보를 조사, 분석하고 보다 더 다양한 공간과 위치에서 장애물에 대한 충격응답의 변화로부터, MPEG-I Immersive Audio 등의 애플리케이션에서 사실적인 공간감을 제공하기 위한 인공적인 충격응답을 가공 방법을 제안할 수 있을 것으로 기대한다.