• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.130-142
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• 2014

The Korean government is considering implementation of the marine ecosystem restoration technology program (MERTP) to analyze the current status of the marine ecosystems and causes for the ecosystem deterioration as well as to eventually establish a master strategic plan for restoring ecosystem functions and preventing ecosystem functional loss. In order to determine likelihood of successful implementation, it is essential to perform an analysis of the economic feasibility of the program. The present study assessed economic feasibility of the MERTP. To this end, the dichotomous choice contingent valuation (CV) method is used. In particular, dichotomous choice (DC) format is employed as a method of eliciting willingness-to-pay (WTP) response to incentive-compatible mechanisms. The study also employed the spike model to deal with zero WTP responses from the DC CV survey. This survey of 1,000 randomly selected households in accordance with the guidelines provided by the National Oceanic and Atmospheric Administration (USA) was carried out nationwide in 2013. And, the respondents were asked in person-to-person interviews about their WTP for implementing the MERTP. The results showed that the annual mean WTP was estimated to be 5,414 won per household. Consequently, the annual benefit from the MERTP would be about 98.6 billion won for the next five years. Economic feasibility assessment utilizing the MERTP investment cost and expansion cost of the value provided that net present value, benefit/cost ratio, and internal rate of return are 337.8 billion won, 5.20, and 65.9 %, respectively, which are bigger than 0, 1.0, and 5.5 %, and that the MERTP passes the cost-benefit analysis.

• 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 Korean Society of Coastal and Ocean Engineers
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• v.32 no.1
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• pp.55-68
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• 2020

In order to investigate the hydraulic characteristics of a boundary layer streaming over the beach cusps appeared in swells prevailing mild seas, we numerically simulated the shoaling process of Edge waves over the beach cusp. Synchronous Edge waves known to sustain the beach cusps could successfully be duplicated by generating two obliquely colliding Edge waves in front of beach cusps. The amplitude A_B and length L_B of Beach Cusp were elected to be 1.25 m and 18 m, respectively based on the measured data along the Mang-Bang beach. Numerical results show that boundary layer streaming was formed at every phase of shoaling process without exception, and the maximum boundary layer streaming was observed to occur at the crest of sand bar. In RUN 1 where the shortest waves were deployed, the maximum boundary layer streaming was observed to be around 0.32 m/s, which far exceeds the amplitude of free stream by two times. It is also noted that the maximum boundary layer streaming mentioned above greatly differs from the analytical solution by Longuet-Higgins (1957) based on wave Reynolds stress. In doing so, we also identify the recovery procedure of natural beaches in swells prevailing mild seas, which can be summarized such as: as the infra-gravity waves formed in swells by the resonance wave-wave interaction arrives near the breaking line, the sediments ascending near the free surface by the Phase II waves orbital motion were carried toward the pinnacle of foreshore by the shoreward flow commenced at the steep front of breaking waves, and were deposited near the pinnacle of foreshore due to the infiltration.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.531-540
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• 2009

In this study, thermo-gravimetric analysis(TGA) was used to investigate the effect of urea concentration and heating rate on the ammonia($NH_3$) formation process from urea solution. A newly designed pipe nozzle was inserted through a 1,000 N${\ss}$(C)/h oil firing boiler to compare the DeNOx efficiencies between the upward and downward nozzle. This experiment reveals the effect of path which an urea droplet goes through. Urea solution showed the same TGA graph without regard to the presence of oxygen. Heating rate had a great influence on the weight loss trend. But the concentration of urea solution between 10% and 40% did not affect so much the thermal decomposition temperature. Therefore, heating rate is more important factor on the thermal decomposition of urea than the concentration of urea solution. Three nozzles located at different positions showed similar DeNOx efficiencies such as 68.1%, 71.8%, 70.8% at the same temperature. Even though urea solution was injected for the same zone, the injection direction made much difference in DeNOx efficiency. A upward nozzle showed 68.1% and downward nozzle 9.5%. This results illustrate the importance of heating rate.

• Economic and Environmental Geology
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• v.44 no.6
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• pp.513-523
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• 2011

We estimated geothermal power generation potential in Korea through Enhanced Geothermal System (EGS) technology following the recently proposed protocol which was endorsed by international organizations. Input thermal and physical data for estimation are density, specific heat and thermal conductivity measurements from 1,516 outcrop samples, 180 heat production, 352 heat flow, and 52 mean surface temperature data. Inland area was digitized into 34,742 grids of $1'{\times}1'$ size and temperature distribution and available heat were calculated for 1 km depth interval from 3 km down to 10 km. Thus estimated theoretical potential reached 6,975 GW which is 92 times total generation capacity of Korea in 2010. Technical potential down to 6.5 km and considering land accessibility, thermal recovery ratio of 0.14 and temperature drawdown factor of $10^{\circ}C$ was 19.6 GW. If we disregard temperature drawdown factor, which can be considered in estimating economic potential, the technical potential increases up to 56 GW.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.264-271
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• 2004

A three-dimensional numerical mesoscale model by Pielke's estimation (University of Virginia Mesoscale Model, UVMM) was applied to investigate the effects of land characteristics including land-humidity, land-roughness and land-albedo on some micro-climatic coefficients and the air cooling capacity. The results indicated that land-characteristics exposed a significant effect on air cooling. Air cooling effects between in urban and agricultural areas were compared and the effects were much higher in agricultural area. Air cooling effects of weed species were different and when converted into economic values by diesel oil price the effects were ranged from 411 to 816 Won/plant.

• Korean Journal of Microbiology
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• v.25 no.4
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• pp.333-338
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• 1987

In order to establish the biological treatment system which can be used for treatment of waste aster from acetaldehyde plant, it was investigated optimum nutrient requirements and growth conditions by mixed culture of Micrococcus roseus AW-6, Micrococcus luteus AW-22, Microbacterium lacticum AW-38 and Microbacterium laevaniformans AW-41 as well as the effect of coagulants and neutralization reagents. Also, it was carried out the continuous culture as well as batch culture to treat the waste water by mixed culture of these strains. The COD removal rate was reached to maximum state for 96hrs culture at pH7.0 and $30^{\circ}C$ NaOH as the neutralization reagents was the most effective, but the coagulants had no effect on the COD remonal rate and the optimum dilution times for treatment were 10 fold. The COD removal rate was also increased by supplimenting 200 ppm $NH_{2}NO_{3}$, 50 ppm $KH_{2}PO_{4}$, 15 ppm $CaCl_{2}$ and 1 ppm $MgSO_{4} \cdot 7H_{2}O $ as additional nutrients. The removal rate coefficient $K_{1}$ on the batch culture was $4.5\times 10^{-6}$, and the detention time for BOD removal rate of 85% was approximately 45hrs. The COD of waste water was reduced to 15% of its initial value by the continuous culture. The COD and BOD of the effluents were to be about 60 ppm and 40 ppm, respectively, and final pH was 7.0.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.647-655
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• 2021

The IMO (International Maritime Organization) is discussing the improvement of energy ef iciency of ships in order to reduce greenhouse gas emissions from ships. Currently, by applying an ORC power generation system using waste heat generated from ships, high energy conversion efficiency can be expected from ships. This technology uses an organic medium based on Freon or hydrocarbons as the working fluid, which evaporates at a lower temperature range than water. Through this, it is possible to generate steam (gas) and generate power at a low and low temperature relatively. In this study, the analysis of heat flow between the refrigerant and waste heat in the ORC power generation system, which is an organic Rankine cycle, is analyzed using 3D simulation techniques to determine the temperature change, velocity change, pressure change, and mass change of the fluid flowing of the WHRU (Waste Heat Recovery Unit) inside and the outside the structure. The purpose of this study is to analyze how the mass change affects the structure, and this study analyzed the heat transfer of the heat exchanger from the refrigerant and the exhaust gas of the ship's main engine in the ORC power generation system using this technique.

• Journal of the Korean Society of Earth Science Education
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• v.14 no.2
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• pp.146-158
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• 2021

We are to introduce an example of ESD in connection with SDGs through liberal arts courses opened at the College of Education. We analyzed the awareness of the carbon footprint expressed by 42 preservice teachers in a class designed in connection with SDGs 13 goal, 'climate action'. The pre-service teachers wrote a carbon diet diary, a checklist for the level of practice that emits carbon in daily life, and freely expressed the source and proportion of their carbon emissions through the carbon footprint drawing activity. In items of electricity use, public transportation use, and garbage disposal, the level of practice was positive, but water use was analyzed in a negative way. The pre-service teachers who expressed the carbon footprint in 2-3 items reached a majority, showing limitations in recognizing the carbon emission situation in their daily life. Pre-service teachers will be the main actors of education on the environmental issues of the earth at the school site, and the carbon literacy of pre-service teachers will directly or indirectly affect students. We hope that various ESD programs linked to the 17 SDGs will be developed and applied to the educational field to contribute to sustainable global environmental education.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.377-386
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• 2021

The A60 class deck penetration piece is a fire-resistant system installed on a horizontal compartment to prevent flame spreading and protect lives in fire accidents in ships and offshore plants. This study deals with approximate optimization using discrete variables for the fire resistance design of an A60 class deck penetration piece using different surrogate models and a genetic algorithm. Transient heat transfer analysis was performed to evaluate the fire resistance design of the A60 class deck penetration piece. For the approximate optimization of the piece, the length, diameter, material type, and insulation density were applied to discrete design variables, and temperature, productivity, and cost constraints were considered. The approximate optimum design problem based on the surrogate models was formulated such that the discrete design variables were determined by minimizing the weight of the piece subjected to the constraints. The surrogate models used in the approximate optimization were the response surface model, Kriging model, and radial basis function-based neural network. The approximate optimization results were compared with the actual analysis results in terms of approximate accuracy. The radial basis function-based neural network showed the most accurate optimum design results for the fire resistance design of the A60 class deck penetration piece.