• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.672-680
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• 2023

Weight is a critical factor in the ship design process given that it has a substantial impact on the hydrodynamic performance of ships. Typically, ships are optimally designed for specific conditions with a fixed draft and displacement. However, in reality, weight and draft can vary within a certain range owing to operational activities, such as fuel consumption, ballast adjustments, and loading conditions . Therefore, we investigated how resistance changes under three different loading conditions, namely overload, design-load, and lightship, for small craft, using both model experiments and numerical simulations. Additionally, we examined the sensitivity of weight changes to resistance to enhance the performance of ships, ultimately reducing power requirements in support of the International Maritime Organization's (IMO) goal of reducing CO2 emissions by 50% by 2050. We found that weight changes have a more significant impact at low Froude Numbers. Operating under overload conditions, which correspond to a 5% increase in draft and an 11.1% increase in displacement, can lead to a relatively substantial increase in total resistance, up to 15.97% and 14.31% in towing tests and CFD simulations, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.420-426
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• 1999

We examined the immune response in flounder, Paralichthys olivaceus, with immunization of formalin killed Edwardsiella tarda as an antigen. The ELISPOT-assay (enzyme-linked immunospot assay) was optimized technically and applied to count the number of total and specific antibody secreting cells (TASC and SASC) in lymphocytes of different lymphatic organs. Incubation of lymphocytes on 96 well plate for more than 2.5hrs came out enough time in ELISPOT-assay for counting the antibody secreting cells in the anterior kidney and spleen. However, too much of plate-coated antigen or rabbit anti-flounder immunoglobulin for SASC or TASC counting, respectively, was appeared to decrease the sensitivity of the assay system. Specificity of the system was also confirmed by the absence of TASC in lymphocytes treated with cycloheximide to prevent protein synthesis. The peak numbers of SASC appeared at wk 3 post immunization after that there was a sharp decrease and reached to almost zero at wk 7. In the spleen and kidney, the timing and numbers of SASC on peak response were concurrent without preferential organ distribution. The specific antibody level in the sera increased rapidly between wk 2 and 3 after immunization, i.e. like the specific cellular response found with ELISPOT-assay on that period, However, the remained high level of specific serum antibody from wk 5 after immunization until the end of experiment was clearly distinguishable from the kinetics of SASC response decreased sharply.

• Resources Recycling
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• v.19 no.4
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• pp.3-12
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• 2010

Countries which have a lot of metal resources are weaponizing metal resources such as supply limitation, high price sale. It's necessary for us to establish the countermeasure for recycling of used metal resources on a government basis. Ministry of Environment has established and announced the project for finding and reuse the hidden metal resources as pan-government department pass the Cabinet meeting at September 22, 2009. This countermeasure, 10 years project, is classified into 2 steps. Aim of this project is advance of the recycling technology and industry, achievement of recycling rate, 75%, improvement in adverse balance of trade, 1.25 billion US$.

• Tunnel and Underground Space
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• v.28 no.3
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• pp.247-257
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• 2018

High-speed trains have been developed widely in many countries in order to transport large quantity of people and commodities rapidly. When a high speed train enters a tunnel, aerodynamic resistance is generated suddenly. The resistance caused from air pressure induces micro pressure wave and discomfort to passengers in a train. Therefore, a pressure relief system should be installed in a tunnel to reduce the resistance acting against the running train in a tunnel. Additionally, the shape of a grain should be streamlined in order to reduce aerodynamic resistance caused by a high-speed train. The cross-section of a tunnel also should be carefully designed to reduce discomfort of passengers. This study represents the effect of pressure relief ducts installed between two running tunnels. The pressure relief duct was integrated with a cross-passage in order to save cost and construction time. One-dimensional network numerical simulations were carried out in order to estimate the effect of pressure relief systems.

• Journal of Navigation and Port Research
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• v.28 no.5
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• pp.359-364
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• 2004

When sea going vessel approaches her destination port, marine traffic density is increased, especially, the marine traffic is concentrated in the entrance channel and the fairway in the inner harbour is more narrow. Therefore, special navigational rules for preventing collision at sea is needed in the inner harbour. Hence there are the rules in The Public Order in Open Port Act in Korea But, in the case of conflict of navigational rule concerned, it is possible to be raised a question that which rule shall be applied preferentially. Also, it is necessary to understand the exact meaning of the navigational rules in The Public Order in Open Port Act. Because the misunderstanding of the rule is caused the collision Therefore, this paper aims to discuss the exact meaning of the navigational rule concerned in the view of legal basis and suggest the principles for a proper application of it.

• Land and Housing Review
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• v.3 no.3
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• pp.271-278
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• 2012

The climate change and global warming has been a world-wide issue. Also, the green growth has been a widely adopted strategy for national and regional development. In particular, after the Kyoto Protocol to United Nations Framework Convention on Climate Change was declared, the low carbon society was inevitable phenomenon. The hydrologic cycle in urban catchment has been changed due to the expansion of impervious area by rapid urban development. This paper has examined the Water cycle planning elements for green city in the scale of urban planning as well as site planning including housing site. In this study, the SWMM5-LID (Storm Water Management Model5-LID) model was used to simulate the hydrologic cycle of the test catchment as a typical urban catchment. We performed continuous simulation on urban runoff before and after the development of the test catchment and after the installation of Green city planning Elements.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.199-204
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• 2016

The adsorption of Rhodamine-B dye using granular activated carbon from aqueous solution was investigated. Adsorption experiments were carried out as a function of the adsorbent dose, pH initial concentration, contact time and temperature. The equilibrium adsorption data showed a good fit to Langmuir isotherm model. Based on the estimated Langmuir separation factor ($R_L$ = 0.0164~0.0314), our adsorption process could be employed as an effective treatment method. The kinetics of adsorption followed the pseudo first order model. Also, the negative values of Gibbs free energy (-4.51~-13.44 kJ/mol) and positive enthalpy (128.97 kJ/mol) indicated that the adsorption was spontaneous and endothermic process. The isosteric heat of adsorption increased with increase in the surface loading indicating lateral interactions between the adsorbed dye molecules.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.236-248
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• 2019

Green belts can help to set boundary for city growth, provide ecological protection system and enhance the resilience of Beijing. During the implementation period of the current overall city planning of Beijing, the proportion of green space varies much among the sub-districts, villages and towns involved in the two green belts in the research. With this as starting point, by researching the correlations of 'city system factors' and 'planning policy factors' with the change in the scale of green space, the paper discussed the influential factors of implementing the planning of green space of Beijing, and conducted quantitative research, with such possible influential factors classified into 'city system factors' and 'planning policy factors'. Through multiple linear regression model, the paper tested the correlations of city system factors and planning policy factors (independent variable) with the increment in the construction land in green belts (dependent variable). Through influence to population aggregation and the expansion force of construction land, city system factors such as mountain land and water, house rent of unit area, accessibility of public transport and the newly-defined state-owned construction land generate correlation with the change in the scale of construction land in green belts.

• Journal of ILASS-Korea
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• v.25 no.4
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• pp.196-203
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• 2020

Nowadays, urea SCR technology is considered as the most effective NOx reduction technology of diesel engine. However, low NOx conversion efficiency under low temperature conditions is one of its problems to be solved. This is because injection of UWS (Urea Water Solution) is impossible under such a low temperature condition due to the problem of insufficient of urea decomposition and urea deposits. In several previous studies, it has been reported that appropriate control of the amount of ammonia adsorbed on SCR catalyst can improve the NOx conversion efficiency under low temperature conditions. In this study, we tried to find out how much the NOx conversion efficiency increases with respect to the amount of ammonia adsorbed on the catalyst, and what the temperature conditions that the ammonia slip occurs. This study shows the results of 8 times repeated WHTC test with a diesel engine, in which UWS was injected with NH3/NOx mole ratio of '1'. Through this study, it was found that 13% of the NOx conversion efficiency of WHTC increased while the θ (ammonia adsorption rate) increased from "0%" to "22%". In addition, it is found that in cases of high θ value, the significant improvement of NOx conversion efficiency at low temperatures presented during the beginning period of WHTC and at high temperature and transient conditions presented during last part of WHTC test. The NH3 slip occurring condition was 250℃ of catalyst temperature and 10% of θ, and the amount of NH3 slip increased as the temperature and θ are increased.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.419-427
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• 2021

Due to the effects of climate change and the reduction of the labor force due to COVID-19, the crop yield, harvest time, and cultivated area are rapidly changing every year. In order to respond flexibly to this situation, attempts to apply smart farm technology based on ICT (Information and Communication Technology) to individual farms are increasing. On the other hand, various stakeholders are trying to predict the yield of crops using artificial intelligence and IoT technology, but accurate prediction is difficult due to the lack of learning data. In this study, in order to overcome the data collection problem limited to a specific institution, a smart farmer service technology based on community mapping was developed in which farmers directly participate, input and share accurate data to predict production. In the process, analysis was performed on napa cabbage, which is a vegetable with a large price change compared to production.