• New & Renewable Energy
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• v.1 no.3 s.3
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• pp.42-50
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• 2005

This paper deals with the economic feasibility model and analysis of a hydrogen fuel-cell vehicle [FCV] against two similar types of non-business vehicles fueled with gasoline [GV] and diesel [DV] considering greenhouse gas [GHG]. Considering the price of vehicles and annual operating cost, we build a classical economic feasibility model. Since the economic feasibility could be affected by many input factors such as the prices of vehicles, the price of fuels, annual driving distance and so on, we estimate the average future values of input factors, which is defined as "the average case". Based on the average case, we assess the representative economic feasibility of a FCV with/without GHG, and by changing various annual driving distances, we assess its economy in terms of net-present value, internal rate of return, and payback period. In addition, we make some sensitivity analysis of its economic feasibility by changing the values of the critical input factors one at time. Based on the average case, it turns out that the consumer of a FCV could save 25,000 won/year for a GV, but the consumer could pay 120,000 won/year more for a DV. This indicates that gasoline vehicles could be replaced gradually by FCVs in Korean market which might be formed by those consumers driving annually more than approximately 14,800 km. As the results of our sensitivity analysis, it turns out that a FCV is no more economical if the difference of the prices between FCV and GV is more than 10,130,000 won or the price of hydrogen fuel could be more than 5,136 won/kg.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.390-390
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• 2018

산업화에 따른 온실가스 배출량 증가는 심각한 기후변화의 요인으로 작용하여 우리나라를 포함한 전세계는 이에 대응하고자 노력하고 있다. 지구온난화 및 엘리뇨 현상 등으로 인하여 가뭄, 홍수, 한파, 혹서 등의 재해와 기상이변이 속출하고, 최근 우리나라의 경우 매년 가뭄이 발생하고 있어 이에 대한 대책이 시급한 실정이다. 이에 가뭄의 대처방안에 대한 관심이 증대 되었고, 가뭄을 정량적으로 하는 연구들과 기후변화에 따른 가뭄 취약성 평가에 대한 연구들이 진행 되었다. 가뭄의 취약성 평가는 기후변화에 따른 가뭄 저감을 위한 목적에 따라 평가목적, 평가방법, 필요한 정보, 과정의 설계 불확실성에 대한 고려 등이 달라진다. 취약성 평가의 목적은 크게 기후영향평가, 적응정책의 자원배분을 위한 취약부문 및 지역 파악, 적응정책 개발을 위한 적응 대안 분석으로 나눌 수 있다. 취약성 평가의 목적이 취약성 유발요인에 관한 정보를 제공하여 어디에 적응 대책에 필요하고 효과적일 수 있는지 파악하는데 도움을 주는 것이라면, 취약성 결정요인에 대한 분석을 명료하고 상세하게 수행하는 것이 중요하다. 본 연구에서는 기후변화에 따른 농업용수의 취약성 평가지표를 개발하기 위하여 국내 외 취약성 평가 지표를 분석, 국내 농업기상 및 농업용수 등 관련 자료(1981 ~ 2015)의 조사 현황을 고려하여 취약성 평가지표(강우량, 증발산량, 경지면적, 저수용량, 용수로 통수능력, 수요량, 하천평수위)를 제시하고 국내 농업기상 및 농업용수 등 관련 자료의 조사 현황을 고려하여 대상지구인 충북 진천 무수 관개지구에 취약성 지표를 적용하였다. 강우의 증가는 가뭄 취약성에 긍정적 영향을 나타냈고, 증발산량의 증가는 부정적인 영향을 나타냈다. 경지면적의 감소는 소비수량이 증가하므로 가뭄 취약성에 긍정적인 영향을 나타냈고, 저수 용량의 감소는 홍수조절능력의 저하로 인해 부정적인 영향을 끼치고, 하천 홍수위의 변화는 가뭄에 영향을 미치는 요소 중의 하나로 홍수위가 높아지면 가뭄에 부정적인 영향을 나타냈다. 가뭄 취약성 지표들을 각각의 가중치를 합산한 결과, 1981년~2015(5년 분할) 무수지구의 가뭄 취약성 평가는 분석을 시작한 1981년부터 2015년 까지 안전과 우려가 반복 되는 것으로 나타났다. 연구대상지구의 농업기상 및 관련 자료들의 조사 기간이 길면 빈도별 신뢰성이 높아진다. 따라서 자료의 누적은 정확한 기후변화에 대한 이수 및 치수 취약성 평가 지표개발 및 평가 능력을 높여 줄 수 있을 것으로 판단된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.681-691
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• 2017

In this research, life cycle inventory database (LCI DB) was developed for elastomeric bearing employing life cycle assessment (LCA) methodology additionally the reliability improvement rate in the evaluation of the environmental load of the bridge was analyzed. As are result of impact assessment by 6 major impact categories, production of elastomeric bearing puts on environmental impact in the order of resource depletion, global warming, photochemical oxidant creation. and among a wide variety of input, steel plates contributes in most of the impact categories. As a result of applying the elastomeric bearing LCI database constructed in this study, the environmental loads increased by 0.53% on average, and the cut-off based on the cost of input materials increased by 11.36%. It is anticipated that it will be possible to improve the credibility and to provide data based on current production technology, such as estimating GHG emissions and evaluating environmental load, by constructing elastomeric bearing LCI DB.

• Journal of the Korea Society of Computer and Information
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• v.17 no.1
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• pp.211-218
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• 2012

Fossil fuel is used all over the world and it produces greenhouse gases due to fossil fuel use. Therefore, it cause global warming and is serious environmental pollution. In order to decrease the environmental pollution, we should use renewable energy which is clean energy. Among several renewable energy, wind energy is the most promising one. Wind power generation is does not produce environmental pollution and could not be exhausted. However, due to wind power generation has irregular power output, it is important to predict generated electrical energy accurately for smoothing wind energy supply. There, we consider use ramp characteristic to forecast accurate wind power output. The ramp increase and decrease rapidly wind power generation during in a short time. Therefore, it can cause problem of unbalanced power supply and demand and get damaged wind turbine. In this paper, we make prediction models using power ramp rate as well as wind speed and wind direction to increase prediction accuracy. Prediction model construction algorithm used multilayer neural network. We built four prediction models with PRR, wind speed, and wind direction and then evaluated performance of prediction models. The predicted values, which is prediction model with all of attribute, is nearly to the observed values. Therefore, if we use PRR attribute, we can increase prediction accuracy of wind power generation.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.12
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• pp.1281-1286
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• 2008

Nitrous oxide(N$_2$O) is well known as a greenhouse gas that contributes to the global warming (310 times more per molecule than carbon dioxide) and to the destruction of the ozone layer. The objective of this study is to estimate N$_2$O emission factor using an emission isolation flux chamber from municipal wastewater treatment plants. N$_2$O gas was analysed by GC/ECD with 6 port gas sampling valve. The results of this study were as follows. N$_2$O emission factor of 5-Stage process from Y wastewater treatment plants was lowest as 0.94 g-N$_2$O/kg-TN. And that of other processes were 2.65 g-N$_2$O/kg-TN for Activated sludge process, 9.30 g-N$_2$O/kg-TN for Denipho process, and 26.73 g-N$_2$O/kg-TN for Sequencing Batch Reactor process. We have known that 5-Stage process is most appropriate process to reduce greenhouse for municipal wastewater treatment plants.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1232-1238
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• 2011

This experiment was conducted to measure concentration of dissolved $N_2O$ in ground-water of 59 wells and to make emission factor for assessment of indirect $N_2O$ emission at agricultural sector in agricultural areas of Gyeongnam province from 2007 to 2010. Concentrations of dissolved $N_2O$ in ground-water of 59 wells were ranged trace to $196.6{\mu}g-N\;L^{-1}$. $N_2O$ concentrations were positively related with $NO_3$-N suggesting that denitrification was the principal reason of $N_2O$ production and $NO_3$-N concentration was the best predictor of indirect $N_2O$ emission. The ratio of dissolved $N_2O$-N to $NO_3$-N in ground-water was very important to make emission factor for assessment of indirect $N_2O$ emission at agricultural sector. The mean ratio of $N_2O$-N to $NO_3$-N was 0.0035. It was greatly lower than 0.015, the default value of currently using in the Intergovernmental Panel on Climate Change (IPCC) methodology for assessing indirect $N_2O$ emission in agro-ecosystems (IPCC, 1996). It means that the IPCC's present nitrogen indirect emission factor ($EF_{5-g}$, 0.015) and indirect $N_2O$ emission estimated with IPCC's emission factor are too high to use adopt in Korea. So we recommend 0.0034 as national specific emission factor ($EF_{5-g}$) for assessment of indirect $N_2O$ emission at agricultural sector. Using the estimated value of 0.0034 as the emission factor ($EF_{5-g}$) revised the indirect $N_2O$ emission from agricultural sector in Korea decreased from 1,801,576 ton ($CO_2$-eq) to 964,645 ton ($CO_2$-eq) in 2008. The results of this study suggest that the indirect Emission of nitrous oxide from upland recommend 0.0034 as national specific emission factor ($EF_{5-g}$) for assessment of indirect $N_2O$ emission at agricultural sector.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.55-55
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• 2011

기후변화는 지구 온난화와 같은 인위적인 변화와 기후 자체의 자연적인 변동성에 기인하고 있으며 기후변화의 영향으로 인해 물관리 분야에도 영향을 받고 있다. 이러한 기후변화의 영향은 가용 수자원량의 예측과 이를 관리하는 측면의 불확실성을 증가 시키고 있으며 미래 물관리가 더욱 어려울 것으로 전망되고 있다. 이에 본 연구에서는 기후변화에 대응한 수자원의 종합적인 관리 차원에서 시공간적 물수급 불균형 해소를 위한 방법론을 제시하고자 유역 물관리 모형인 KModSim을 이용하여 낙동강유역을 대상으로 수자원 네트워크를 구축하였다. 유역의 자연유량을 산정하기 위하여 SWAT 모형을 이용하였으며, 현실적으로 유역의 물관리 문제에 접근하기 위해서 낙동강 유역의 수리시설물, 생 공용수 및 농업용수, 댐용수 및 하천수 점용허가 등의 수리권 자료에 근거하여 KModSim을 구축하였다. 미래 기후변화 시나리오(온실가스 배출이 현 수준에서 지속될 것으로 가정한 균형적 발전 시나리오인 A1B 사용)를 적용하였으며 현재(1980~2009년)와 미래(2011~2100년)를 각각 30년씩 구분하여 기후변화에 대한 생활 공업 농업용수의 수요량 변화, 하천유지용수의 공급 변화, 다목적 댐 모의 운영 결과를 검토하였다. 낙동강 유역의 상류 다목적댐의 용수공급 능력은 2040년 초반부터 저류량이 감소 등 물공급에 심한 영향을 받을 것으로 전망되었다. 이와 같은 기후변화의 영향은 수요량에 대응하는 저수지의 공급능력에 영향을 주게 되어 물공급 시설의 운영에 어려움이 있을 것으로 전망되었다. 농업용수에 대한 기후변화의 영향평가 결과 또한 2041년부터 2070년의 기간에 부족이 발생하는 것으로 모의되었다. 생활과 공업용수의 물공급은 기존의 물공급 시설 투자 덕분으로 기후변화의 영향이 두드러지지 않은 것으로 나타났으나 일부 지역은 기후변화에 영향을 고려하지 않더라도 취약한 것으로 모의 되었다. 하천유지유량의 경우 지류가 본류에 비해 하천유지유량의 확보가 어려운 것으로 나타났지만 양적으로는 본류가 부족량이 더 많은 것으로 모의되었다.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.36-42
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• 2007

Korean paddy soils have long been almost uniformly managed throughout the whole country with flooded, deep tillage, puddlling, transplanting, and uncovering after harvest. Management of soil organic carbon could be more important in the sources of green house gases. However, soil organic carbon dynamics were not been studied for Korean paddy soils. Therefore, we evaluated the changes in soil organic carbon (SOC) of paddy soils between 1999 and 2003 at the same locations nationwide except islands. Soil organic carbon tends to increase in Inceptisols, which is predominant soil order for Korean paddy soils, from 1999 to 2003. Soil organic carbon increases in topographically plain paddy soils was greater than in valley soils, and was considerably high in predominant types of paddy soils (i.e., well adapted paddy soils, sandy paddy soils, and poorly drained paddy soils) but low and stable in the saline paddy soils. We also found that clay paddy soils are greater in soil organic carbon than sandy paddy soils. Through this study, we concluded that a proper management of paddy soils could contribute to soil organic carbon storage, which imply that the Korean paddy soils could help to enhance carbon dioxide sequestration via soil organic matter into the soil.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.284-301
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• 2023

The changes in rice climatic yield potential (CYP) across the Korean Peninsula are evaluated based on the new climate change scenario produced by the National Institute of Agricultural Sciences with 18 ensemble members at 1 km resolution under a Shared Socioeconomic Pathway (SSP) and Representative Concentration Pathways (RCP) emission scenarios. To overcome the data availability, we utilize solar radiation f or CYP instead of sunshine duration which is relatively uncommon in the climate prediction f ield. The result show that maximum CYP(CYPmax) decreased, and the optimal heading date is progressively delayed under warmer temperature conditions compared to the current climate. This trend is particularly pronounced in the SSP5-85 scenario, indicating faster warming, except for the northeastern mountainous regions of North Korea. This shows the benef its of lower emission scenarios and pursuing more efforts to limit greenhouse gas emissions. On the other hand, the CYPmax shows a wide range of feasible futures, which shows inherent uncertainties in f uture climate projections and the risks when analyzing a single model or a small number of model results, highlighting the importance of the ensemble approach. The f indings of this study on changes in rice productivity and uncertainties in temperature and solar radiation during the 21st century, based on climate change scenarios, hold value as f undamental information for climate change adaptation efforts.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.892-897
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• 2010

LCA (Life Cycle assessment) was carried out to estimate on carbon footprint and to establish of LCI (Life Cycle Inventory) database of sweetpotato production system. Based on collecting the data for operating LCI, it was shown that input of organic fertilizer was value of 3.26E-01 kg $kg^{-1}$ and it of mineral fertilizer was 1.02E-01 kg $kg^{-1}$ for sweetpotato production. It was the highest value among input for sweetpotato production. And direct field emission was 2.47E-02 kg $kg^{-1}$ during sweetpotato cropping. The result of LCI analysis focussed on greenhouse gas (GHG) was showed that carbon footprint was 4.05E-01 kg $CO_2$-eq. $kg^{-1}$ sweetpotato. Especially $CO_2$ for 71% of the GHG emission and the value was 2.88E-01 kg $CO_2$-eq. $kg^{-1}$ sweetpotato. Of the GHG emission $CH_4$, and $N_2O$ were estimated to be 18% and 11%, respectively. It might be due to emit from mainly fertilizer production (32%) and sweetpotato cultivation (28%) for sweetpotato production system. $N_2O$ emitted from sweetpotato cultivation for 90% of the GHG emission. With LCIA (Life Cycle Impact Assessment) for sweetpotato production system, it was observed that the process of fertilizer production might be contributed to approximately 90% of GWP (global warming potential). Characterization value of GWP and POCP were 4.05E-01 $CO_2$-eq. $kg^{-1}$ and 5.08E-05 kg $C_2H_4$-eq. $kg^{-1}$, respectively.