• 대한토목학회논문집
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• 제32권1D호
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• pp.71-80
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• 2012

수도권의 기능 및 범위 확대로 인하여 광역교통수요가 급증하였고, 이러한 광역교통수요를 충족시키기 위해서는 다양한 광역대중교통 보급이 필요하다. 하지만 막대한 투자재원을 필요로 하는 광역교통시설의 설치 및 운영 관리에 대한 명확한 기준과 제도의 부족으로 중앙정부와 지방정부, 지방정부와 지방정부 사이에서 갈등이 일어나고 있는 실정이다. 본 연구에서는 수도권 광역 BRT, 광역 환승시설 등의 효율적인 설치 및 운영 관리를 위한 재원분담 모델을 개발하여 재원분담기준을 설정하고자 하였다. 이에 국내외 사례를 기반으로 광역 BRT 시설의 주요 구성요소인 광역 BRT 노선, 광역 환승시설 그리고 공영차고지의 재원분담 모형을 정립하고 정립된 재원분담모형을 적용하여 대안별 비교분석을 수행하였다.

• The Journal of Asian Finance, Economics and Business
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• 제7권9호
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• pp.603-611
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• 2020

Higher education has long been considered as a means of human resource development in a nation. The faculty member plays a significant role in improving the quality of higher education. It is clear that job satisfaction and motivation have effect on the faculty member's performance. The objective of this study is to investigate the levels and factors affecting lecturers' motivation in Vietnamese public universities. In this study, ordinary least squares (OLS) and exploratory factor analysis (EFA) have been utilized to identify the factors affecting work motivation of lecturers at Vietnamese universities. A questionnaire was administered to a sample of 189 lecturers at different public universities in Vietnam. The finding indicates that seven factors including Work characteristics (WC), Wage and welfare (WW), Social recognition (SR), Peer relationships (PR), Training and promotion opportunities (PO), Leader caring (LC) and Teacher-student interaction and student's attitude (IA) have positive effect on lecturers' work motivation. Among these factors, Teacher-student interaction and student's attitude (IA) has the strongest impact with the coefficient of 0.631 and Peer relationships (PR) has the least impact on work motivation with the coefficient of 0.020. The study findings can facilitate the understanding of how to increase work satisfaction at the universities in Vietnam.

• Journal of Preventive Medicine and Public Health
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• 제45권6호
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• pp.335-343
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• 2012

Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental ($Hg^0$) and divalent ($Hg^{2+}$) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly $Hg^{2+}$, can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans.

• 방사성폐기물학회지
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• 제15권4호
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• pp.381-390
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• 2017

국내 원자력발전소의 사용후핵연료는 소내저장시설에 보관되어 있으나 저장시설의 용량 확장이 어려움이 있으며, 연구기관의 연구로에서 발생하는 고준위 방사성폐기물도 자체 보관중이나 영구적으로 저장할 수 없다. 또한 원전의 해체 시에도 고준위 방사성폐기물이 발생할 것으로 예상된다. 이에 따라, 본 연구에서는 현재 개발된 사용후핵연료 운반용기를 사용하여 고준위 방사성폐기물을 가상의 관리시설로 철도를 통하여 운반하는 경우에 대하여 작업자 및 운반경로 주변 일반인의 예상 피폭선량을 평가하였으며, 그 결과를 국내 법적기준치와 비교하였다. 또한, 고준위 방사성폐기물의 상하차 작업 시 작업자와 운반용기 간 거리와 운반사고 시 방사성핵종의 누출율의 변화에 따른 피폭선량의 변화에 따른 피폭선량 추이와 운반에 사용되는 열차의 구성에 따른 운반작업자의 피폭선량 변화를 분석하였다. 본 연구에서 설정한 모든 조건에서의 예상피폭선량은 국내 법적제한치 이하임을 확인하였다.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2008년도 제7회 추계학술대회 및 정기총회
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• pp.25-28
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• 2008

• 방사성폐기물학회지
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• 제21권2호
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• pp.255-269
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• 2023

Compared to operational wastes, nuclear power plant (NPP) decommissioning wastes are generated in larger quantities within a short time and include diverse types with a wider range of radiation characteristics. Currently used 200 L drums and IP-2 type transport containers are inefficient and restrictive in packaging and transporting decommissioning wastes. Therefore, new packaging and transport containers with greater size, loading weight, and shielding performance have been developed. When transporting radioactive materials, radiological safety should be assessed by reflecting parameters such as the type and quantity of the package, transport route, and transport environment. Thus far, safety evaluations of radioactive waste transport have mainly targeted operational wastes, that have less radioactivity and a smaller amount per transport than decommissioning wastes. Therefore, in this study, the possible radiation effects during the transport from NPP to disposal facilities were evaluated to reflect the characteristics of the newly developed containers and decommissioning wastes. According to the evaluation results, the exposure dose to transport workers, handling workers, and the public was lower than the domestic regulatory limit. In addition, all exposure dose results were confirmed, through sensitivity analysis, to satisfy the evaluation criteria even under circumstances when radioactive materials were released 100% from the container.

• 소성∙가공
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• 제22권1호
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• pp.42-47
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• 2013

The bicycle is one of the most important eco-friendly transport methods which can mitigate global warming. The portability of a bike on public transportation systems is essential for the wide spread use of bicycles by people in urban environments. In this study, a lightweight urban folding bike was developed with careful consideration of the association with public transport. A folding frame using a moving slide link mechanism made from AL6061 is proposed. Numerical analysis was conducted to evaluate structural safety of the bike in both vertical and pedal loading tests. The proposed urban folding bicycle weights only 10kg and summation of its width, length, and height in the folded configuration is under 158cm.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.430-433
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• 2003

Nitrogen pollution in urban and rural groundwater is a common problem and poses a major threat to drinking water supplies based on groundwater. In this work, the kinetics of nitrification-denitrification coupled reactions are modeled and new reaction modules for the RT3D code describing the fate and transport of nitrogen species, dissolved oxygen, dissolved organic carbon, and biomass are developed and tested. The proposed nitrogen transformations and transport model showed very good match with the results of other public codes.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.24-31
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• 2000

We have the common aim of encouraging freight to be carried by rail rather than by road because there are sufficient environmental, social and public benefits. Thus it is important to lead to freight traveling by rail rather than road and to ensure that freight on rail does not transfer to road. In Korea, taking freight off road and moving it by rail is more expensive from a point of total transport costs. Hence this paper is focused in the improvement methods for the rail freight transport which could be helped to promote the efficiency associated with moving freight by rail.

• Structural Monitoring and Maintenance
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• 제6권3호
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• pp.219-235
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• 2019

Scheduled inspections of common crossings are one of the main cost drivers of railway maintenance. Prognostics and health management (PHM) approach and modern monitoring means offer many possibilities in the optimization of inspections and maintenance. The present paper deals with data driven prognosis of the common crossing remaining useful life (RUL) that is based on an inertial monitoring system. The problem of scheduled inspections system for common crossings is outlined and analysed. The proposed analysis of inertial signals with the maximal overlap discrete wavelet packet transform (MODWPT) and Shannon entropy (SE) estimates enable to extract the spectral features. The relevant features for the acceleration components are selected with application of Lasso (Least absolute shrinkage and selection operator) regularization. The features are fused with time domain information about the longitudinal position of wheels impact and train velocities by multivariate regression. The fused structural health (SH) indicator has a significant correlation to the lifetime of crossing. The RUL prognosis is performed on the linear degradation stochastic model with recursive Bayesian update. Prognosis testing metrics show the promising results for common crossing inspection scheduling improvement.