• Journal of Energy Engineering
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• v.25 no.4
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• pp.110-123
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• 2016

Since increase in energy consumption and environmental issues started to grab global attention, various countries have had their own supporting policy to promote supply of renewable energy which is a stable and eco-friendly energy source. This study analyses Korean Renewable Portfolio Standard by comparative analysis of current policies in major countries in respect of design components of a pragmatic industrial policy system, such as political leadership, policy coordination and consultative committee discussion, and policy enforcement with responsibility and transparency. This is to identify problems and to present political suggestions for successful management of the standard based on a fundamental concept of the pragmatism industrial policy. It is predicted that the strategic cooperation between a market and a government leads to industry development as the relationships of two parties are regarded not as antagonistic but as complementary.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.791-802
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• 2014

Energy shortage is being exacerbated due to the increase of energy consumption and depletion of fossil fuels. In order to release the energy crisis, new types of energy resources such as small hydropower, solar power, wind power and biomass have been already developed or actively researched. Recently, osmotic power, which harvests energy from salinity gradient between seawater and fresh water, is considered as a feasible candidate. Among the osmotic power processes, pressure retarded osmosis (PRO) is widely gaining attention because of no emission of carbon dioxide and less sensitivity to the external environmental conditions. However, PRO process is facing difficulties such as the lack of specialized PRO membrane and optimization technologies. Therefore, PRO was reviewed in this paper in terms of theoretical background, membrane development, process development and fouling mechanism to provide insights and suggest the future direction of PRO research.

• Journal of Environmental Impact Assessment
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• v.23 no.4
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• pp.237-250
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• 2014

A wide range of projects for ocean renewable energy are currently in development around the world and ocean energy industries continue to receive significant support from their governments. Surrounded by sea on three sides, Korea has potentially abundant renewable ocean energy resources, which include tidal current, tidal range, offshore wind power, osmotic pressure and ocean thermal energy. Numerous ocean renewable energy projects has been developed in Korea. Nevertheless, there are some concerns that those developments often select an environmentally unsuitable location and/or there are very few existing information on those environmental effects. The purpose of this study is to improve supporting policies and regulation systems of ocean renewable energy development in Korea by reviewing and compiling government policies and environmental assessment systems related to ocean renewable energy development around the world. The study suggests several policy implications for its environmental-friendly development in Korea, including requirements of strategic environmental assessment for proactive and environmentally suitable site selection of ocean renewable energy development and continuous post-development environmental monitoring, and so on.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.35-44
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• 2018

Korea government aims to generate 20 percent of its electricity with clean, renewable energy by 2030, while reducing its reliance on fossil fuel and nuclear power plants. Technically, solar energy has resource potential that far exceeds the entire global energy demand. Solar energy industry has experienced phenomenal growth in recent years due to both technological improvements resulting in cost reductions and government policies for renewable energy development and utilization. Even though solar power generation has several advantages over other forms of electricity generation, the major problem is the requirement of land which is scarcely available in the local site and its cost. This study analyzes the available capacity of landing and floating solar plants for the case of chonnam province in korea. The results of design capacity show about 7.5GW for landing and 1.5GW for floating solar power plant. Also, with a purpose to comprehend intention-behaviour gap about acceptance of solar community, the solutions are suggested.

• Journal of the Korean Solar Energy Society
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• v.27 no.4
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• pp.1-9
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• 2007

Sensitivity analysis of wind resource micrositing has been performed through the application case at the Antarctic King Sejong station with the most representative micrositing softwares: WAsP, WindSim and Meteodyn WT. The wind data obtained from two met-masts separated 625m were applied as a climatology input condition of micro-scale wind mapping. A tower shading effect on the met-mast installed 20m apart from the warehouse has been assessed by the CFD software Fluent and confirmed a negligible influence on wind speed measurement. Theoretically, micro-scale wind maps generated by the two met-data located within the same wind system and strongly correlated meteor-statistically should be identical if nothing influenced on wind prediction but orography. They, however, show discrepancies due to nonlinear effects induced by surrounding complex terrain. From the comparison of sensitivity analysis, Meteodyn WT employing 1-equation turbulence model showed 68% higher RMSE error of wind speed prediction than that of WindSim using the ${\kappa}-{\epsilon}$ turbulence model, while a linear-theoretical model WAsP showed 21% higher error. Consequently, the CFD model WindSim would predict wind field over complex terrain more reliable and less sensitive to climatology input data than other micrositing models. The auto-validation method proposed in this paper and the evaluation result of the micrositing softwares would be anticipated a good reference of wind resource assessments in complex terrain.

• Journal of the Korean Magnetics Society
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• v.22 no.6
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• pp.221-227
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• 2012

High performance permanent magnets have become the subject of considerable attention because of the potential applications in the traction motors of hybrid and electric vehicles and wind generators. Nd-Fe-B magnets have attracted considerable interest due to a large maximum energy product. However, Nd-Fe-B magnet cannot be used in high temperature (${\sim}200^{\circ}C$) applications due to the thermal degradation of coercivity. Therefore, the development of high coercivity Nd-Fe-B permanent magnet is a challenging issue. In case of high coercivity Nd-Fe-B permanent magnet, an increment in the intrinsic coercivity can be easily achieved by substituting Nd atoms with Dy or Tb atoms. However, these heavy rare-earth elements are known to cause a decrease in remanence due to the antiferromagnetic coupling between Dy and Fe atoms. In addition, Dy is relatively expensive and being limited in quantity. Hence, a new technology that can increase the coercivity of Nd-Fe-B sintered magnet using only a small amount, or even, no amount of heavy rare-earth elements is being investigated. This article describes the research trend in reducing the heavy rare-earth elements in Nd-Fe-B magnets.

• Atmosphere
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• v.20 no.2
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• pp.63-71
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• 2010

In this study, we derived the wind speed at 50 m and 80 m above sea level from 567 stations over a period of 1 year and correlated to measured wind speed at 5 radiosonde sites. From these correlations, we derived and analyzed the spatial distribution of wind map over Korea based on hourly observational data recorded over a period of 5 years from 2004 to 2008. As a results, wind speed is generally high over seashores, mountains, and islands. Mean wind speed over Korea at 50 and 80 m above sea level for 5 years during 2004 to 2008 seasonally are highest at Spring, and then followed by Winter, Fall, and Summer. In 76 (14%) stations, mean wind speed at 80 m above sea level for 5 years during 2004 to 2008 are greater than $5ms^{-1}$. The prevailing winds over Korea at 80 m above sea level for 5 years during 2004 to 2008 are North (44%), Northwest (16%), and West (15%). In 99 stations, the % of wind faster than $5ms^{-1}$ was higher than 40%, and in 62 stations, the % of wind faster than $5ms^{-1}$ was higher than 50%. In 178 station, the % of prevailing winds was higher than 30%, and there are 7 stations which also have wind speeds over $5ms^{-1}$, ranking from highest to lowest, Dongsong, Daegwallyeong, Baekun Mt., Hyangrobong Mt., Sorak Mt., Gosan, and Misiryeong Mt..

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.247-252
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• 2015

The majority of electric power in the domestic manned islands with off-grid power system is supplied by the diesel generators. However, in the case of off-grid islands the fuel cost is more expensive to inland areas and difficult to transport them to islands. So the development of renewable energy system using natural resource have been recently introduced. But renewable energy that depend on the natural environment, it is necessary to organized the hybrid system with existing diesel engine because the energy is difficult to maintain stable electric power. This paper presents the results of a feasibility study of hybrid system with energy storage system such as wind, solar, battery and diesel engine. The study included off-grid island as the Seogeochado islands located in Jeolanamdo Province. And, the paper proposed a optimal capacity of hybrid system configuration to maintain carbon free with minimum investment cost. the analysis of economic adaptability performed by HOMER program.

• Journal of the Korean Solar Energy Society
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• v.36 no.1
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• pp.49-61
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• 2016

The power production using hub height wind speed tends to be overestimated than actual power production. It is because the hub height wind speed cannot represent vertical wind shear and blade tip loss that aerodynamics characteristic on the wind turbine. The commercial CFD model WindSim is used to compare and analyze each power production. A classification of atmospheric stability is accomplished by Monin-Obukhov length. The concentric wind speed constantly represents low value than horizontal equivalent wind speed or hub height wind speed, and also relevant to power production. The difference between hub height wind speed and concentric equivalent wind speed is higher in nighttime than daytime. Under the strongly convective state, power production is lower than under the stable state, especially using the concentric equivalent wind speed. Using the concentric equivalent wind speed considering vertical wind shear and blade tip loss is well estimated to decide suitable area for constructing wind farm.

• Journal of the Korean Solar Energy Society
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• v.36 no.1
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• pp.11-18
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• 2016

The local wind systems in the Pohang region were categorized into wind sectors. Still, thorough knowledge of wind resource assessment, wind environment analysis, and atmospheric environmental impact assessment was required since the region has outstanding wind resources, it is located on the path of typhoon, and it has large-scale atmospheric pollution sources. To overcome the resolution limitation of meteorological dataset and problems of categorization criteria of the preceding studies, the high-resolution wind resource map of the Korea Institute of Energy Research was used as time-series meteorological data; the 2-step method of determining the clustering coefficient through hierarchical clustering analysis and subsequently categorizing the wind sectors through non-hierarchical K-means clustering analysis was adopted. The similarity of normalized time-series wind vector was proposed as the Euclidean distance. The meteor-statistical characteristics of the mean vector wind distribution and meteorological variables of each wind sector were compared. The comparison confirmed significant differences among wind sectors according to the terrain elevation, mean wind speed, Weibull shape parameter, etc.