• Bulletin of the Korean Chemical Society
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• 제11권4호
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• pp.343-347
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• 1990

A thermal decomposition of the tert-butoxy radical has been studied in the gas phase over the pressure range of 1-200 torr at $413_{\circ}K$ using di-tert-butyl peroxide + trimethylsilane mixtures. The relative rate constants were obtained by studying the competitive reactions between tert-butoxy radical decomposition 4(t-BuO·→ CH_3COCH_3 + CH_3·)$ and hydrogen abstraction reaction from trimethylsilane $(t-BuO·+ HSi(CH_3)_3 → t-BuOH + Si(CH_3)_3)·).$ The conventional RRKM calculations were carried out to compare the observed fall-off behavior of the decomposition rate constant $({\kappa}_d)$ with the theoretical predictions using reasonable values of input parameters. In all cases the calculated half-rate pressure $(P_{1/2})$ were significantly higher than those observed. The failure of RRKM to reproduce the fall-off behavior led us to suggest that not all of vibrational modes contribute to excitation (leading to decomposition) on the same time scale.

• 한국가시화정보학회지
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• 제20권2호
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• pp.38-44
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• 2022

Due to increasingly strict emission regulations for carbon-based fuels in the shipping industry, there is a significant motivation to investigate the alternative fuel. Ammonia is one of the attractive alternative fuels as a carbon-free fuel. Since ammonia has different properties such as high vapor pressure and low boiling point compared to conventional fuels, further research into ammonia spray behavior is important. In this work, the spray characteristics of ammonia and other fluids (ethanol, n-decane) were compared by using numerical simulation. The results show that the spray characteristics of ammonia differs from those of the others due to the occurrence of flash boiling. The narrow-dispersed spray with accelerated velocity at the center have been observed for ammonia. It is also found that droplets of ammonia achieve smaller diameter with more uniform distribution, leading to better atomization behavior compared to the others.

• 한국멀티미디어학회논문지
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• 제25권2호
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• pp.421-431
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• 2022

The purpose of this research is to determine the point of fixation of the driver during the process of driving. Based on the results of this research, the driving instructor can make a judgement on what the trainee stare on the most. Traffic accidents have become a serious concern in modern society. Especially, the traffic accidents among unskilled and elderly drivers are at issue. A driver should put attention on the vehicles around, traffic signs, passersby, passengers, road situation and its dashboard. An eye-tracking-based application was developed to analyze the driver's gaze behavior. It is a prototype for real-time eye tracking for monitoring the point of interest of drivers in driving practice. In this study, the driver's attention was measured by capturing the movement of the eyes in real road driving conditions using these tools. As a result, dwelling duration time, entry time and the average of fixation of the eye gaze are leading parameters that could help us prove the idea of this study.

• Geomechanics and Engineering
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• 제28권5호
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• pp.455-461
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• 2022

Numerical assessment of the dynamic stability behavior of nonlocal beams rested on elastic foundation has been provided in the present research. The beam is made of fucntional graded (FG) porous material and is exposed to thermal and humid environments. It is also consiered that the beam is subjected to axial periodic mechanical load which especific exitation frequency leading to its instability behavior. Beam modeling has been performed via a two-variable theory developed for thick beams. Then, nonlocal elasticity has been used to establish the governing equation which are solved via Chebyshev-Ritz-Bolotin method. Temperature and moisture variation showed notable effects on stability boundaries of the beam. Also, the stability boundaries are affected by the amount of porosities inside the material.

• 한국주조공학회지
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• 제43권6호
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• pp.294-301
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• 2023

The effects of Cu on feeding and macro-porosity characteristics were investigated in hypo- (A356 and 319) and hypereutectic (391) aluminum-silicon alloys. T-section and Tatur tests showed that the feeding and macro-porosity characteristics were significantly different between the hypo- and hypereutectic alloys. The hole and the pipe in the T-section and the Tatur casting in hypereutectic alloy showed a rough and irregular shape due to the faceted growth of the primary silicon, while the results of the hypoeutectic alloys exhibited a rather smooth surface. However, the addition of Cu did not strongly affect the macro-feeding behavior. It is known that copper segregates and interferes the feeding process in the last stage of solidification, possibly leading to form more amount of micro shrinkage porosity by the addition of Cu. The macro porosity formation mechanism and feeding properties were discussed upon T-section and Tatur tests together with an alloying addition.

• 한국가정과교육학회지
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• 제16권3호
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• pp.147-161
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• 2004

본 연구의 목적은 대학생들의 세탁행동, 세탁인지도 및 환경보전을 위한 의생활 행동 실태를 파악하고, 대학생들의 인구통계학적 특성 변인에 따른 세 측면의 차이를 조사하여 주부가 아닌 성인을 대상으로 한 효과적이고 친환경적인 세탁관련 교육프로그램 개발에 필요한 기초 자료를 제공하는 것이었다. 분석을 위한 설문지는 2003년 11월에 충북에 위치한 한국교원대학교 기숙사생들에게 직접 배포하여 수집하였다. 연구 결과 대학생들의 세탁인지도는 전반적으로 높았음에도 불구하고, 세탁의 효율을 저하시키고, 여러 자원의 낭비와 인체 및 자연환경을 오염시키는 세탁행동을 하고 있는 것으로 나타났다. 또한, 대학생들의 환경보전을 위한 의생활 행동은 낮은 수준이었다. 인구통계학적 특성 변인에 따른 차이에서는 여학생이 남학생보다, 세탁 관련 학습경험이 있는 학생이 학습경험이 없는 학생보다 세탁인지도가 상대적으로 높았고 세탁효과를 높일 수 있는 방법으로 세탁을 실시하고 있었다. 이상과 같은 결과는 대학생들의 효과적이고 친환경적인 세탁행동을 유도하기 위해서는 단순 지식 전달이 아닌 실제 생활에서 환용이 가능한 세탁교육 프로그램을 개발하여 실시할 필요가 있음을 시사한다.

• 한국방사선학회논문지
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• 제17권6호
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• pp.939-945
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• 2023

본 연구는 영상의학 분야에서 인공지능(AI) 기술 기반의 판독 보조 시스템의 'Time Behavior(시간반응성)' 속성을 측정하여 '성능 효율성'을 분석하였다. 의료 영상의 증가와 영상의학 전문의 수의 한계로 인해 인공지능(AI) 기술 기반의 솔루션이 증가하고 있으며, 관련된 연구가 많이 수행되고 있다. 하지만 대부분의 선행 연구가 인공지능의 진단 정확도에 초점을 맞췄다면, 본 연구는 Time Behavior의 중요성을 강조하여 수행하였다. 50개의 흉부 엑스레이 PA 이미지를 사용하여 측정한 결과, 평균 15.24초 만에 영상을 처리하여 높은 일관성과 안정성을 보여주었고, 이 처리 속도는 유명 글로벌 AI 플랫폼과 동등한 수준으로 영상의학과 워크플로우 효율성 부분에 크게 개선될 수 있는 가능성을 제시하였다. 앞으로 인공지능 기술이 영상의학 분야에서 큰 역할을 담당하여, 전반적인 의료 품질 향상과 효율성을 개선하는 데 도움이 될 것으로 기대한다.

• 한국문헌정보학회지
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• 제58권1호
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• pp.417-439
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• 2024

본 연구는 공공도서관 사서들의 혁신행동이 조직 성과인 서비스 품질에 미치는 영향을 분석하였다. 이를 위하여 본 연구는 수도권 공공도서관 7곳의 사서 및 이용자를 대상으로 설문조사를 실시하여 사서 데이터 77건, 이용자 데이터 309건을 분석 대상으로 삼았다. 사서를 대상으로 혁신행동을, 이용자를 대상으로 서비스 품질을 조사하였다. 분석 결과, 혁신행동의 완성 단계인 아이디어 구현은 정보통제 차원에 정적(+) 영향을 미치는 것으로 나타났다. 다만, 혁신행동의 첫 단계인 아이디어 생성은 서비스의 영향력과 정보통제 차원에 부적(-) 영향을 미치는 것으로 나타났다. 아이디어 생성에 머무르고 아이디어 홍보와 구현 등 다음 단계로 나아가지 않는 상황은 서비스 품질을 저하시키는 것으로 해석되었다. 본 연구는 공공도서관에 혁신행동 개념을 적용하였으며 공공도서관 사서들의 혁신행동이 서비스 품질에 미치는 영향을 실증 연구를 통해 제시하였다는 데에서 의의를 찾을 수 있다.

• 한국학교ㆍ지역보건교육학회지
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• 제15권1호
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• pp.121-140
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• 2014

Objectives: Recently, the rate of death by chronic disease, is increasing steadily. To prevent this, the public health center will have taken a leading role in the local community medical business through an establish to the national health promotion act and an amendment to the law of public health center in Korea. Results: Accordingly this research, using the Pender's health promotion model which is related with subject health behavior who government employees serve at the public health center have taken important position in the local community health promotion, have comprehended the actual condition of health behavior. For increasing the health behavior practice of subject to comprehend the factor which have effect on health behavior practice, which can be a correct role model in the local community health promotion. A survey was performed on 406 government employees who serve at five public health centers in Seoul. The period of survey was from 25th October, 2010 to 15th November, 2010. The results of this study were summarized as below. 1. Work-related stress, perceptible beneficial obstacle, and self-efficacy were composed by 5 points measure. The results show those work-related stress were $3.06{\pm}0.469$, 74perceptible beneficial obstacle were $3.74{\pm}0.471$, and self-efficacy were $3.49{\pm}0.469$. 2. As for the health behavior by general characteristic, the results have specific differences on age, education level, state of marriage, rank of the position, field of the occupation and employment forms in statics analysis. 3. As for the past health behavior by health behavior characteristic, work-related stress have specific differences on the past frequency of drinking (p<.05) in statics analysis, perceptible beneficial obstacle have specific differences on the past frequency of having breakfast(p<.05), having snacks(p<.05) and doing exercise(p<.05) in statics analysis. Self-efficacy have specific difference on the past frequency drinking(p<.01) in statics analysis. 4. According to the correlation between the factors related with health behavior and health behavior, the health behavior have specific differences on perceptible health condition(p<.01), the past health behavior and perceptible beneficial obstacle(p<.05). Work-related stress and self-efficacy don't have specific relation in health behavior practice. 5. The factors, which effect on health behavior practice have specific differences on the past health behavior, employment forms and field of the occupations. The ability of explanation occupied 54.8% what explained of the health behavior practice by general characteristic, perceptible health condition, employment forms and perceptible beneficial obstacle. Conclusions: According to the correlation between the factors related with health behavior, the health behavior have specific differences on perceptible health condition(p<.01), the past health behavior and perceptible beneficial obstacle(p<.05). The factors, which effect on health behavior practice have specific differences on the past health behavior, employment forms and field of the occupations.

• 대한임상검사과학회지
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• 제44권1호
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• pp.7-16
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• 2012

The Korean GDP per capita doubled during the last 10 years. As the GDP increases, Korean health behaviors such as, eating, drinking, smoking, and exercise habits changed as well. Compared to the remarkably advanced diagnostic technologies and therapeutics during the last decade, the leading causes of death in Korea scarcely changed. Among the leading causes of death, cerebrovascular disease, heart disease, diabetes, liver disease and hypertension are closely related to health behaviors. Using the database of medical check-up between 2001 and 2010, the authors performed a longitudinal study for the prevalence rates and the trends of major chronic adult diseases among the 2,721 workers along with their health behavior. Among the diagnostic test items, fasting blood sugar, cholesterol and BMI levels showed steady increase and these three test items all showed linear trends (p<0.001). The average blood sugar and cholesterol levels were near worrying levels. Moreover, the average BMI of males was found to be at the overweight level, intimating the possibility reaching thee Obese Class I level soon if there are no aggressive counter measures. Fasting blood sugar and cholesterol levels were higher in a drinking group as compared to a non-drinking group, and the BMI levels were also higher in the drinking group and the smoking group as compared to the non-drinking and the non-smoking group (p<0.001). Finally, the authors believe that the fasting blood sugar, cholesterol and BMI levels should be designated as target monitoring test items in the medical check-up for Korean employees.