• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.733-753
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• 1994

Monthly mean sea levels from 103 tidal stations in Korea, Japan, and Russia are analyzed to study long-period sea level variations. Barometric adjustment are done for all the sea level data, using monthly air pressures at sea levels from meteorological stations near tidal stations. Seasonal variation is dominant in most of study area. It is the largest in the coasts along the Tsushima Current, and the smallest in the Russian coasts. The cross-correlations of seasonal variations are very high between the coasts along the Tsushima Current. In these marginal seas, seasonal variations seem to be related with the Tsushima Current. The phase of seasonal variations is generally getting late from south to north, and also from west to east. On the other hand, longer-period variations(longer than seasonal variation) have the largest amplitudes and the earliest phases in the coasts along the Pacific Ocean, which shows that they propagate from the Pacific Ocean. Shorter-period variations (shorter than seasonal variation) have generally lower cross correlations. Their values do not show any dictinct difference between areas, and show a common tendency that they are inversely proportional to distance. It implies that the shorter period waves are generated all over the study areas, and propagate in all the directions with faster dissipations. The trends of sea levels in the study area are generally negative in the coasts along the Pacific Ocean and positive in the other areas during the period of 1965 to 1985. By the trends, the mean volume transport between Cheju and Sasebo can be reduced by about 1 Sv during the period. The seasonal variation of volume transport obtained by sea level difference is about 2 Sv in the Korea Strait. The values are comparable to previous reports.

• Journal of Energy Engineering
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• v.19 no.2
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• pp.116-120
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• 2010

Overall total length of hydraulic pipe to transport the hot water in the domestic district heating network is above 3,000 Km approximately. This long pipe network requires a lots of the transport pumping power by surface friction of fluid. In this study, the drag reduction(DR) of Amin Oxide $C_{18}$ as non-ionic surfactant according to the fluid velocity, temperature and surfactant concentration under the condition of above $80^{\circ}C$ fluid temperature were investigated experimentally. Results showed that new amin oxide $C_{18}$ surfactant had DR of maximum 30% in fluid temperature of $80^{\circ}C$ and had 15% DR in fluid temperature over $100^{\circ}$ under short time test condition. And amine oxide had 155 hours duration time to keep the DR characteristic in the fluid temperature of $80^{\circ}$ and 1000 ppm concentration. But duration time of DR was decreased when fluid temperature increased.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.6
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• pp.450-457
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• 2019

Sedimentation is a common problem for river ports. But its intensity depends on the rate of sedimentation, channel shape and size, hydrodynamic behavior of the river and the importance of the port. High sedimentation rate in Yangon River has become one major issue for Myanmar as her largest port is located on the Yangon riverbank. As a result of the high sedimentation rate, shallow water area near the confluence of Yangon River, Pazundaung Creek, and Bago River keeps blocking the navigation channel to the Yangon Port, which also limits the size of vessel calling to Yangon Port. Therefore, studies to understand sediment transport process in Yangon River are required because the economic development of Myanmar highly relies on the Yangon Port. This paper aims to calculate the sediment transport and to predict the riverbed elevation changes in Yangon River by using Bagnold (1966) theory. Calculation result shows that huge difference can be found in the bed load transport between the rainy season and dry season in Yangon River, and thus the sedimentation problem would become more severe in the dry season when the transported sediments are reduced. The estimated sedimentation rate in dry season indicates that the rate of riverbed level rise near the Yangon Port area is about 0.063 m per year, which would lead to approximately 3.15 m rise in the riverbed level in next 50 yrs, considering the same workload of dredging to maintain the navigation channel.

• Environmental and Resource Economics Review
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• v.16 no.2
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• pp.275-311
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• 2007

Hydrogen energy is emphasized as a substitutable energy of carbon-based energy system in the future, since it is non-depletable and clean energy. Long term vision of Korean government on the national energy system is to promote hydrogen energy by 15% of final energy demand until 2040. This study analyzes economic impacts of hydrogen energy development employing a dynamic CGE model for Korea. Frontier technology such as hydrogen energy is featured as slow diffusion at the initial stage due to the learning effect and energy complementarity. Without government intervention, hydrogen energy would be produced upto 6.5% of final energy demand until 2040. However, if government subsidizes sales price of hydrogen energy by 10%, 20%, and 30%, share of hydrogen energy would increase 9.2%, 15.2%, and 37.7% of final energy demand. This result shows that the slow diffusion problem of hydrogen energy as frontier technology could be figured out by market incentive policy. On the other hand, production levels of transportation sector would increase while growth rate of oil and electricity sectors would decline. Household consumption would be affected negatively since increase of consumption due to the price decrease would be overwhelmed by income reduction owing to the increase of tax. Overall, GDP would not decrease or increase significantly since total production, investment, and export would increase even if household consumption declines.

• Journal of Korea Port Economic Association
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• v.37 no.1
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• pp.197-215
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• 2021

This paper analyzes the machine learning predictions of the economic effects of Busan's strategic industries on the employment and income using the Ridge Regression and Lasso Regression models with regulation terms. According to the Ridge estimation and Lasso estimation models of employment, the intelligence information service industry such as the service platform, contents, and smart finance industries and the global tourism industry such as MICE and specialized tourism are predicted to influence on the employment in order. However, the Ridge and Lasso regression model show that the future transportation machine industry does not significantly increase the employment and income since it is the primitive investment industry. The Ridge estimation models of the income show that the intelligence information service industry and global tourism industry are also predicted to influence on the income in order. According to the Lasso estimation models of income, four strategic industries such as the life care, smart maritime, the intelligence machine, and clean tech industry do not influence the income. Furthermore, the future transportation machine industry may influence the income negatively since it is the primitive investment industry. Thus, we have to select the appropriate economic objectives and priorities of industrial policies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.663-670
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• 2016

This paper analyzes the asymmetric pass-through effects of crude oil price changes on export prices in Korea's manufacturing sector using a nonlinear autoregressive distributed lag (NARDL) model. These pass-through effects are important for Korean companies that are highly dependent on exports. Because the effects differ by industry, eight sectors of the manufacturing industry were examined. The model is effective for separately testing the long-term and short-term differences between the export-price pass-through effects when crude oil prices increase and decrease. The estimation results show that there is positive pass-through to export prices as crude oil prices change, and there are asymmetric effects in some manufacturing sectors. Short-term asymmetries were detected in the export prices of five sectors that include general machinery and transport equipment, and significant long-term asymmetries were found for petroleum and coal products and for textile and leather products. The long-term export price of oil and coal products rose by 0.992% with a 1% increase in the oil price and fell by 0.977% with 1% decrease. Therefore, corporate strategies and government export policies should be established in accordance with these asymmetric pass-through effects.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.592-599
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• 2016

In the 21st yearly session of the Conference of the Parties (COP 21) of the 2015 United Nations Climate Change Conference, held in Paris, France, in December 2015, the "Paris Agreement" was negotiated; this is a new global agreement on the reduction of climate change, which encourages every country to participate in countermeasures for global climate change. Along with such movements, the electric railway sector has also been actively engaged in low carbon technology. This paper studied the building of a 1.5MW photovoltaic power generation system using the rooftop of the Gwangmyeong Station Building, which is the largest roof among the high-speed railway station buildings in Korea; this station has passenger traffic that reached about 7 million in 2014. For this study, we configured an optimized photovoltaic (PV) power generation system and then estimated the expected annual energy production by using PV system software; we also calculated the expected revenue that could be obtained by linking this source to the power distribution system. The obtained data were used to analyze the contribution of low-carbon energy that could be obtained by introducing a PV power generation system on the roof of an electric railway station building.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1017-1028
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• 2006

Japanese railroad companies continued growing by developing diversification based on a railroad enterprise. However, after entering in the 1990s, the diversification model of a railroad company reached the management limit. Under economic depression, A decrease in the birthrate and aging progressed and passenger transport changed to the downward tendency. Nevertheless, since railroad investment was expanded, railroad achievements got worse and price competitiveness with JR East Japan became weak. But the achievements of a diversification section got worse compared with the railroad enterprise. Therefore, group management was thought as important and enterprise reorganization was developed.

• Journal of KIISE
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• v.41 no.12
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• pp.1075-1080
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• 2014

One of the important roles used to ensure victory in a war is to maximize the overall military forces and to make sure that the capability of the military forces can be sustained as much as possible. Although several researchers have proposed various possible methodologies for logistics support, no research trials have been undertaken to investigate logistics support that considers all relevant elements of such. Unlike previous in trials that consider and analyze the system fault ratio as the main methodology, we propose an approach that simultaneously decides and recommends logistic priority by reflecting and combining item costs, transportation, fault-ratio, and system complexity. Also, we designed an algorithm that can recommend optimized logistics support priority using stationary distribution.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.2
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• pp.105-112
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• 2004

A waste container, one of the key components of a multi-barrier system in a potential high level radioactive waste (HLW) repository in Korea ensures the mechanical stability against the lithostatic pressure of a deep geologic medium and the swelling pressure of the bentonite buffer. Also, it delays potential release of radionuclides for a certain period of time, before it is corroded by intruding impurities. Even though the material of a waste container is carefully chosen and its manufacturing processes are under quality assurance processes, there is a possibility of initial defects in a waste container during manufacturing. Also, during the deposition of a waste container in a repository, there is a chance of an incident affecting the integrity of a waste container. In this study, the appropriate Features, Events, and Processes(FEP's) to describe these incidents and the associated scenario on radionuclide release from a container to the biosphere are developed. Then the total system performance assessment on the Initial waste Container Failure (ICF) scenario was carried out by the MASCOT-K, one of the probabilistic safety assessment tools KAERI has developed. Results show that for the data set used in this paper, the annual individual dose for the ICF scenario meets the Korean regulation on the post closure radiological safety of a repository.