• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.141-147
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• 2019

Recently, the biggest issue in the electricity industry is the increase in renewable energy, and various technologies are being developed to ensure the capacity of the power system. In addition, super-grids linking power systems are being pushed to utilize eco-friendly energy between countries and regions worldwide. The HVDC transmission technology is required to link the power network between regions with different characteristics of the power system such as frequency and voltage. Until now, Korea has applied HVDC transmission technology that connects mainland and Jeju Island with submarine cables. But, the HVDC transmission technology is still developing for long-distance high-capacity power transmission from power parks on the east coast to load-tight areas near the metropolitan area. Considering the high population density and mountainous domestic environment, it is pushing for commercialization of the design technology of the ${\pm}500kV$ Double Bipole with metallic return wire transmission line to transmit large-scale power of 8 GW using minimal right of ways. In this paper, the insulation characteristics were studied for the design of double-bipole transmission tower with metallic return wire, which is the first time in the world. And the air insulation characteristics resistant to the various overvoltage phenomena occurring on transmission lines were verified through a full-scale impulse voltage test.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.2
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• pp.469-480
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• 2019

The purpose of this study is to enhance the cultural heritage value of the Juk-Bang-Ryeum (Bamboo Weir) and prove the originality through the review of historical literature. The main industry of Korean was agriculture and fishery from ancient. In the ancient, fishery instruments are not enough due to the lack of fishing technology. The Juk-Bang-Ryeum was considered as important national resources and asset. It give us many implications about the wisdom of our ancestors because of it's scientific principle of the structure. It is surely a cultural heritage to preserve in the future because it is considered as important community asset as well as more natural and environment oriented fishing method. In the literature, the origin of 'Juk-Bang-Ryeum' can be found as 'Eo-Ryang' or 'Bang-Ryeum'. The records on this terminology go back to the Corea Dynasty, but their documentary records are rare, and most of them are records of the Chosun Dynasty. In this study, we surveyed mainly the literature records about the southern coast region in the period of Chosun Dynasty. This study contributes for preserving the cultural assets of our ancestors who pursued eco-friendly fishery method, and it is also of great significance to produce objective data based on records for the registration of the World Record Heritage.

• Korea Science and Art Forum
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• v.37 no.2
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• pp.101-112
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• 2019

Regardless of the size, the role and meaning of the space required for human daily life are the same. Especially, as the spatial design is small and the size is small, the careful design and problem solving are needed to enable comfortable and convenient life even in a narrow space. The purpose of this study is to design a convergence model that utilizes the advantages of BIM, which can simulate actual design based on a new one-person housing space design plan optimized for one person. This study applied the BIM design technology to one-person housing 2D design, and the suitability examination and the space optimization design of the interior design were carried out. As a result of the study, utility of space improvement, consideration of housing environment, interference check, application of eco-friendly housing system, and MEP design item were derived. Therefore, BIM space design in interior space has been confirmed as a way to overcome limit and inefficiency of 2D design which is applied to actual space by various space design elements. Based on the results of this study, the One-person housing space model, which is applied to the study, is a pure creation designed based on various one-person housing of social and cultural peculiarities derived from previous research. This design example was applied to BIM technology to confirm the detailed and practical design possibility.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.281-289
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• 2021

Commercially used disposable cups undergo fragmentation in the environment and become microplastics (MPs). These MPs can be ingested by aquatic organisms and cause a range of adverse effects. We assessed the acute and chronic toxicity of disposable cup-derived MP fragments in Daphnia magna. MP fragments were identified as a polyethylene terephthalate (PET) fragment with a size of 33.18 ± 7.76 ㎛. The presence of three additives including 1- Propanone. 1-phenyl-3-[2-(phenylmethoxy)phenyl]-, p-Xylene and ethylbenzene was analyzed from MP fragments. The 48 h acute toxicity revealed that 20 % of immobilization and mortality were found at the highest concentration of PET MP (200 mg L^-1). The 21 d chronic toxicity revealed that PET MP fragments significantly (p < 0.05) more reduced survival rate (31 %), total offspring (52 %) in D. magna compared with control group. The developmental abnormality of offspring (3.5%) by PET MP fragments was significantly (p < 0.05) higher than control groups (0.3%). These results are possibly induced by gut blocking by ingestion of MP fragments and their longer retention time. These findings indicate that the fragmentation of disposable cups (PET polymers) into small-sized MP fragments pose a significant ecological risk to aquatic organisms. Further studies are required to elucidate the underlying toxicity mechanisms.

• Korean Journal of Organic Agriculture
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• v.29 no.1
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• pp.97-109
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• 2021

Plant parasitic nematodes are causing significant damage in crop production. There is a need to develop eco-friendly nematicide that reduces the damage of nematode and has little effect on the environment and human. In this study, we have isolated a substance having nematicidal activity from Ginkgo biloba L. outer seedcoat. Studies of G. biloba L. outer seedcoat are insufficient compared to the seed and leaves due to their odor and toxicity. The dried G. biloba L. outer seedcoat was extracted with dichloromethane:methanol (1:1) and fractionated into hexane, ethyl acetate and H₂O. Four steps TLC were performed from EtOAc fraction to purely isolate GB4-3 with nematicidal activity. To compare nematicidal activity, G. biloba L. seedcoat methanol extract and purified GB4-3 were investigated in terms of treatment concentration and time. As a result, the nematicidal activity increased with concentration and time. In the place treated with 20 ㎍/mL of crude G. biloba L. seedcoat MeOH extract, strong activity appeared after 12 hours, and 46% nematicidal activity shown after 18 hours. About 69% of nematicidal activity was confirmed in the place where GB4-3 purified from outer seedcoat was treated with 20 ㎍/mL, and the possibility of development as nematicide was very high. This study could be used as a basic data for the development of a nematode preparation from G. biloba L. outer seedcoat.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.71-82
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• 2018

This study presents a reasonable and economical DCM reinforcement length for the various factors (the embankment height, the distance from the embankment to the underground structure, the depth of the soft ground, and the compression index and the swelling index of the soft ground) that affect the stability of the structure due to lateral movement. Based on these results, we analyzed each factor's degree of influence and figured out which factor influenced the lateral movement most. The cross section of the embankment on the soft ground was modeled by using the Finite Element Program and reinforced with DCM. The results show that the increase rate of the reinforcement length with the increase of the embankment height is about 9~50%, the increase rate of the reinforcement length with the depth of soft ground is about 13~30%, and the increase rate of the reinforcement length with increasing compression index is about 3~25%. In addition, the influence of each factor on each other was analyzed. As a result, among the separation distance, the compressive index and the maximum to minimum slope ratio of the reinforcement length of the embankment height, the separation distance was the largest for the depth of soft ground. As the depth of the soft ground increases, the ratio of the maximum to minimum slope of the reinforcement length according to the embankment height is 3.75, the ratio of the maximum to minimum slope of the reinforcement length according to the spacing distance is 4.3, and the ratio of maximum to minimum slope according to compression index is 2.5. From these results, it is confirmed that the three factors are greatly affected by the depth of soft ground.

• Journal of Climate Change Research
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• v.4 no.3
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• pp.201-210
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• 2013

In recent years, with the rising interest to reduce greenhouse gas emissions, the demand for using environmentally friendly product with low greenhouse gas emission is increasing in the printing industry as well. In this study, the carbon footprint of environmentally friendly product mineral paper that uses less plastic and wood than normal printing paper materials was analyzed by utilizing the life cycle assessment (LCA) technique. An analysis utilizing the LCA technique was done per the Korea carbon footprint certification guidelines and, for scope of study, it included the premanufacturing stage and manufacturing stage except for the use and disposal stages. As a result of the study, the emission coefficient of the mineral paper was calculated to be $0.81kg\;CO_2eq/kg$ and the emission from electricity usage of the entire greenhouse gas emission was calculated to be 45.85% ($0.37kg\;CO_2eq/kg$). In order to reduce greenhouse gas emission, required are the efforts to reduce the environmental loads by using energies that have relatively lower environmental loads, such as improvement in electricity usage efficiency and renewable energy, by increasing product completion rates during the manufacturing process of mineral paper.

• Journal of Climate Change Research
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• v.6 no.1
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• pp.1-10
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• 2015

Climate change lead to environmental pollution caused by the radical economic growth and development of industry. The amount of damage from abnormal climate is increasing rapidly for this reason in Korea. In particular, the cities is a lot of carbon emission quantity from the radical growth. Thus the government present "low carbon green growth" for eco-friendly city planning. As one of the important factors effecting climate change, active researches on land use change is performed. In this study, we knew land use change of each scenarios using land use equilibrium model which is kind of predictive model of land use in Japan. First, we selected study area to Jeju lsland. For this study, indicators for input data were selected and spatial data for input data were established using GIS program. Second, we established future scenarios based in 2040s. There are 2 future scenarios: dispersion scenario, compact scenario. Third, we compared with residential area of current and residential area for future scenarios. Results showed that residential area of the difference between current and dispersion scenario were 1,230 ha and residential area of the difference between current and compact scenario were 1,515 ha. Finally, for comparing carbon dioxide absorption volume between dispersion scenarios and compact scenarios, we calculated carbon dioxide absorption volume according to residential area decreased of each future scenarios. Results showed that carbon dioxide absorption volume in dispersion scenario was 477,878 ton and carbon dioxide absorption volume in compact scenario was 588,606 ton. Therefore, the study showed that land use equilibrium model is expected to put to use for future enhancement in creating data for climate change stabilization. And it is also expected to be utilized for city planning research in Korea.

• The Korean Journal of Mycology
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• v.46 no.4
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• pp.479-490
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• 2018

Red pepper is seriously damaged by thrips (Thrips palmi) and anthracnose caused by Colletotrichum acutatum throughout its development. Because of biotic constraints, producers often depend on chemicals that are expensive and have adverse effects on the environment, operator, and beneficial insects. In addition, resistance is developed because of the repeated use of chemicals. In recent decades, the use of microorganisms in crop protection has become a credible alternative because it is eco-friendly. In this study, we aimed to select isolates with insecticidal and fungicidal activities against the pathogens that cause anthracnose and thrips. We treated T. palmi adults and juveniles with 13 strains of entomopathogenic fungi (isolated from the soil by using the insect-bait method), and 6 strains showed excellent insecticidal activity (70-100%) 5 days after the treatment. The selected isolates were cultured with C. acutatum to screen for the strain with excellent anti-fungal activities, among which an isolate FT333 showed more than 95% control efficacy against C. acutatum in vitro. The isolate was identified as Isaria javanica through its morphological characteristics and phylogenetic analysis of the ITS and ${\beta}-tubulin$ nucleotide sequences. The Isaria javanica FT333 isolate could be used effectively for dual bio-control of thrips and anthracnose during red pepper cultivation.

• Journal of the Korean Institute of Educational Facilities
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• v.25 no.5
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• pp.3-12
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• 2018

The purpose of this study is to examine the degree of appropriateness of using design quality indicators for the educational building, and complements for design quality indicators. For doing this, each items of the Korean educational building design indicator was validated by teachers, school staff and an education officer. First, School Personnel and Teachers considered indicators for the classroom designed for general subjects as being valid. However, in terms of indicators for the outside space, they thought of them as not being valid. In particular, it seemed that school staff would have a passive attitude toward the open of the school facility for the local society. It is judged that there happens an adverse effect caused by the open of the school facility for the local society in the educational environment of the school. Second, Education Office Supervisors thought that eco-friendly indicators, LED lighting, an outer wall, and widows and doors had a high validity. On the contrary, he viewed the validity of a rainwater retention basin as being low, which was likely because he rarely had expertise on the construction. When it comes to the indicator of technology capability, ultrahigh-speed information network was seen as being valid, and the indicator of economic feasibility had high validity on maintenance and durability. Third, compared to groups of Teachers and School Personnel, the group of education officers presented high validity of indicators. Validity of indicators might be differently showed because different items on indicators were measured. However, it is speculated that Education Office Supervisors mostly acknowledged the validity of indicators. Fourth, a majority of Teachers, School staff, and Education Office Supervisors were favor of the system of the evaluation accreditation for school facilities since it played a guide role in improving the quality of school. In order to settle the system of the evaluation accreditation for school facilities, it is most important that institutions in the local society which are publicly reliable should participate in the phase of designing the system of the evaluation accreditation for school facilities. In sum, overall respondents agreed with the system of the evaluation accreditation for school facilities but were aware that reliable organizations in public would need to take part in planning the system of the evaluation accreditation for school facilities from the beginning.