• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1D
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• pp.71-80
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• 2012

Metropolitan transport demand has increased in Seoul Metropolitan Area (SMA) due to the expansion of its role and land use. Various public transport modes have to be supplied to relieve road congestions for the convenience of users. During the constructions of theses infrastructures some conflicts between the central government and local governments arise for sharing financial resources. In this study finance sharing criteria is developed for the metropolitan BRT, transfer facility, and public garages. Finally, a case study has been done for the metropolitan BRT between Cheongra and Hwagok area in SMA.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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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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• v.45 no.6
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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.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.4
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• pp.381-390
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• 2017

In Korea, commercial nuclear power plants and research reactors have on-site storage systems for the spent nuclear fuel, but it is difficult to expand the facilities used for the storage systems. If decommissioning of nuclear power plants starts, an amount of high level radioactive waste will be generated. In this study, a radiological impact assessment of the railroad transport of high level radioactive waste was carried out considering radiation workers and the public, using the developed transport container as the transport package. The dose rates for workers and the public during the transport period were estimated, considering anticipated transport scenarios, and the results compared with the regulatory limit. A sensitivity analysis was also carried out by considering the different release ratios of the radioactive materials in the high level radioactive waste, and different distances between the transport container and workers during loading and unloading phases and while attaching another freight car. For all the anticipated transport scenarios, the radiological impacts for workers and the public met the regulatory limits.

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.25-28
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• 2008

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.2
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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.

• Transactions of Materials Processing
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• v.22 no.1
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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.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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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.

• Proceedings of the KSR Conference
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• 2000.05a
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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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• v.6 no.3
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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.