• Korean Journal of Remote Sensing
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• v.36 no.4
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• pp.587-607
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• 2020

Soil moisture is essential information for meteorological and hydrological analyses. To date, many efforts have been made to achieve the two goals for soil moisture data, i.e., the improvement of accuracy and resolution, which is very challenging. We presented an ensemble downscaling method for quality improvement of gridded soil moisture data in terms of the accuracy and the spatial resolution by the integration of BMA (Bayesian model averaging) and ATPRK (area-to-point regression kriging). In the experiments, the BMA ensemble showed a 22% better accuracy than the data sets from ESA CCI (European Space Agency-Climate Change Initiative), ERA5 (ECMWF Reanalysis 5), and GLDAS (Global Land Data Assimilation System) in terms of RMSE (root mean square error). Also, the ATPRK downscaling could enhance the spatial resolution from 0.25° to 0.05° while preserving the improved accuracy and the spatial pattern of the BMA ensemble, without under- or over-estimation. The quality-improved data sets can contribute to a variety of local and regional applications related to soil moisture, such as agriculture, forest, hydrology, and meteorology. Because the ensemble downscaling method can be applied to the other land surface variables such as temperature, humidity, precipitation, and evapotranspiration, it can be a viable option to complement the accuracy and the spatial resolution of satellite images and numerical models.

• Steel and Composite Structures
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• v.19 no.5
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• pp.1115-1144
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• 2015

Current climate conditions along with advances in technology make further design and verification methods for structural strength and reliability of wind turbine towers imperative. Along with the growing interest for "green" energy, the wind energy sector has been developed tremendously the past decades. To this end, the improvement of wind turbine towers in terms of structural detailing and performance result in more efficient, durable and robust structures that facilitate their wider application, thus leading to energy harvesting increase. The wind tower industry is set to expand to greater heights than before and tapered steel towers with a circular cross-section are widely used as more capable of carrying heavier loads. The present study focuses on the improvement of the structural response of steel wind turbine towers, by means of internal stiffening. A thorough investigation of the contribution of stiffening rings to the overall structural behavior of the tower is being carried out. These stiffening rings are placed along the tower height to reduce local buckling phenomena, thus increasing the buckling strength of steel wind energy towers and leading the structure to a behavior closer to the one provided by the beam theory. Additionally to ring stiffeners, vertical stiffening schemes are studied to eliminate the presence of short wavelength buckles due to bending. For the purposes of this research, finite element analysis is applied in order to describe and predict in an accurate way the structural response of a model tower stiffened by internal stiffeners. Moreover, a parametric study is being performed in order to investigate the effect of the stiffeners' number to the functionality of the aforementioned stiffening systems and the improved structural behavior of the overall wind converter.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.111-119
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• 2007

The annual mean temperature of South Korea has risen by $1.3^{\circ}C$ for last 100 years by urbanization and industrialization. Especially, the frequency of unusual hot weather in summer increases for a long time and the frequency of unusual cold weather in winter clearly decreases. In recently, The considerable portion of curtain wall system is appled to building skin in domestic. As related to this, the Korea Institute of Construction Technology devised the box typed double skin facade(It is occasionally called as FDFS : Functional Double Facade System) as an alternative that reflects the distinctive local climate and saves cooling energy. Two mock-ups($49m^*4.9m$) applied to single skin(curtain wall) and double skin each were monitored under the outdoor condition. Therefore, the characteristics of natural ventilation and cooling energy consumption of each window had been analyzed in real time. The results of this study are summarized as follow, Analysis of the experiment on an air conditioner: the indoor temperature of the chamber with FDFS is lower than that of the chamber with single skin facades by $3{\sim}6$ degrees(C). A temperature variation of about $1{\sim}2$ degrees between the 0.2m and 1.7m height of the mock-up occurs in FDFS, while that of about maximum 7 degrees occurs in single skin facade at noon with abundant intensity of solar accident. Also, 67 percent of energy consumption for air conditioning has been saved.

• Korean Journal of Agricultural and Forest Meteorology
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• v.14 no.4
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• pp.265-268
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• 2012

There are increasing number of allergic patients due to the increasing outdoor activities and allergenic pollens by local climate changes. Korea Meteorological Administration provides daily forecasts for pollen allergy warnings on the Internet. The forecast models are composed of pollen concentration models and risk grade levels. The accuracy of the models was determined in terms of risk grade. Pollen concentration models were developed using the observed data during from 2001 to 2006 and accuracy was validated against the data during from 2010 to 2011. The accuracy was different from location to location. The accuracy for most tree species was higher in April than that in May. The accuracy for weed species was higher in October than in September. Our result suggest that the models presented in this study can be used to estimate daily number and risk grade of pollens.

• Spatial Information Research
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• v.19 no.1
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• pp.61-72
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• 2011

Greenhouses gas emission due to usage of fossil fuel has been known as one of the main causes of global warming. Fundamentally, greenhouse gas is a by-product of economic activity. Since majority of economic activity happens in an urban setting, a countermeasure in an urban setting is needed. Therefore, an analysis of relationship between carbon dioxide emission and urban form will be investigated for urban planning and management in the future. The purpose of this study is to analyze the relationship between carbon dioxide emission and urban spatial patterns, and suggesting an urban form with low carbon dioxide emission. In order to achieve this, first theoretical analysis was carried out on urban spatial patterns related to physical size, usage rate, and activity level. Secondly, Seoul's dam on electricity, natural gas, local heating, petroleum, and water usage and mapping a carbon dioxide emission map. Thirdly, relationship between carbon dioxide emission and urban spatial patterns are analyzed and urban spatial patterns that affects energy usage in urban setting was elucidated, and elicited implications on future directions on urban planning based on our analyses above.

• Fashion & Textile Research Journal
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• v.1 no.1
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• pp.43-49
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• 1999

This study conducted 4 different kinds of underwear materials, which were A (Cotton 100%), B (Wool 100%), C (Cotton/Wool, 50/50%) and D (Acrylic/Cotton, 50/50%) and were done in a climate chamber under cold ambient $10{\pm}1^{\circ}C$, $40{\pm}5%RH$ by 6 male subjects who were in good health. Physiological parameters such as rectal and local skin temperature(forehead, forearm, hand, trunk, thigh, leg, foot, back and chest), heart rate, body weight loss, clothing microclimate, blood lactic acid concentration, and wearing sensation were measured. Started with a 15-min rest period, 15-min of exercise 1 (the condition of 4.5 mile/hr walking speed equivalent to with 8.5 Kcal energy consumption on the treadmill) period, 15-min rest period, exercise 2 (after 3minutes warming-up at 3.0. 3.7, 4.5. 5.2. 6.0, 6.7 mile/hr) until exhaustion period, and final 15-min of recovery period were performed. The results were as follows: The lowest mean skin temperature was acrylic/cotton in order of wool > cotton/wool > cotton > acrylic/cotton (F=13. 79. p<0.00l). Most of all skin temperature by parts of body had turned out in sequence of temperature wool > cotton/wool > acrylic/cotton > cotton. Fore arm part showed highest temperature about $32.43^{\circ}C$ on wool and had a tendency approximately $1.8^{\circ}C$ higher than cotton which had the lowest temperature, and had the biggest difference among garments in terms of skin temperature. The back temperature within clothing showed about $2^{\circ}C$ higher than the chest temperature within clothing. but the back humidity within clothing showed about 4~12% higher than the chest humidity within clothing. Body weight loss by each garment was this sequence; cotton > acrylic/cotton > wool > cotton/wool.

• Journal of Korea Water Resources Association
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• v.48 no.9
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• pp.757-768
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• 2015

Recently, climate change has affected short time concentrated local rainfall and unexpected heavy rain which is increasingly causing life and property damage. In this research, arithmetic average analysis, weighted average analysis, and principal component analysis are used for predicting flood risk. This research is foundation for application of predicting flood risk based on annals of disaster and status of urban planning. Results obtained by arithmetic average analysis, weighted average analysis, and principal component analysis using many factors affect on flood are compared. In case of arithmetic average analysis, each factor has same weights though it is simple method. In case of weighted average analysis, correlation factors are complex by many variables and multicollinearty problem happen though it has different weights. For solving these problems, principal component analysis (PCA) is used because each factor has different weights and the number of variables is smaller than other methods by combining variables. Finally, flood risk assessment considering flood control ability and urban environment risk in former research is predicted.

• Journal of Environmental Impact Assessment
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• v.23 no.1
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• pp.39-50
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• 2014

In recent years, the frequency and scale of the natural disasters are growing rapidly due to the global climate change. In case of the urban flooding, high-density of population and infrastructure has caused the more intensive damages. In this study, we analyzed the spatial characteristics of urban flooding damage factors using GWR(Geographically Weighted Regression) for effective disaster prevention and then, classified the causes of the flood damage by spatial characteristics. The damage factors applied consists of natural variables such as the poor drainage area, the distance from the river, elevation and slope, and anthropogenic variables such as the impervious surface area, urbanized area, and infrastructure area, which are selected by literature review. This study carried out the comparative analysis between OLS(Ordinary Least Square) and GWR model for identifying spatial non-stationarity and spatial autocorrelation, and in the results, GWR model has higher explanation power than OLS model. As a result, it appears that there are some differences between each of the flood damage areas depending on the variables. We conclude that the establishment of disaster prevention plan for urban flooding area should reflect the spatial characteristics of the damaged areas. This study provides an improved understandings of the causes of urban flood damages, which can be diverse according to their own spatial characteristics.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.4
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• pp.379-392
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• 2010

In these days, constructed wetlands are applied in Korea for various purposes ; post-treatment of effluent in wastewater treatment, management of stormwater and restoration of aquatic ecosystems. However, the removal mechanisms for water pollutant in constructed wetlands are not clearly understood because they are affected by climate, influent characteristics and local constraints. Therefore, this paper is focused on the process that the pollutant, especially nitrogen and phosphorus, of the wetland is removed by. In this study, the main nitrogen removal is performed by nitrification/denitrification mechanism in the rhizosphere of constructed wetlands. And the majority of the phosphorus is removed by adsorption on the substrate of wetland. However the fate of phosphorus in wetlands can be diverse depending on the Oxidation Reduction Potential(ORP), adsorption/desorption, precipitation/dissolution, microbial effect, etc.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.5
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• pp.125-134
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• 2018

Recently, interest in alternative energy has been increasing to reduce greenhouse gas emissions and fossil fuel consumption in accordance with the United Nations Framework Convention on Climate Change(UNFCCC). Accordingly, there is a need to use waste heat that unused throughout industrial systems for lowering the concentration of energy on fossil fuels. In particular, government support projects for the energy recycling of agriculture and fisheries such as cultivation of tropical crops and aquaculture are being actively carried out by utilizing waste heat and thermal effluents caused from large-scale industrial complexes including power plants. The study was conducted on supplier (power plant), consumer (farmer) and stakeholders (constructor and local governments) of domestic demonstration areas using waste heat that is abandoned from the power plant in the form of thermal effluents. It investigated the overall improvement and feasibility of government funded projects through field interviews and questionnaire-type surveys. The results of this study are expected to provide basic directions for the operation of the project in terms of nationwide expansion and diffusion of the heat source supply project at horticultural greenhouse by utilizing the thermal effluents from power plant.