• Annual Conference of KIPS
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• 2008.05a
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• pp.435-438
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• 2008

한전에서는 연간 전력 사용량이 높은 고압 고객에 대하여 전자식 전력량계를 설치하여 15분 단위로 전력 사용량을 수집하는 자동검침시스템을 운영하고 있다. 본 연구에서는 자동검침시스템을 통해 수집된 데이터를 이용하여 배전선로에 대한 부하를 분석하기 위해 자동검침 고객의 부하 데이터를 이용하여 클러스터링 기법을 통해 대표 부하패턴을 생성하는 방식을 제안하였다. 기존에는 계약종별 코드가 동일한 고객들의 부하패턴을 이용하여 15분 단위의 평균 사용량을 계산하여 대표 부하패턴을 생성하는 방식을 사용하였으나, 같은 계약종별 코드를 갖는 고객이라 할지라도 부하패턴이 다른 경우가 많아서 부하분석의 정확도를 떨어뜨렸다. 본 연구에서는 동일한 계약종별 코드를 갖는 고객에 대하여 15분 단위 자동검침 데이터를 이용하여 k-means 기법을 통해 고객을 분류하고 각 그룹마다 대표 부하패턴을 생성하는 방식을 제안하였다.

• Journal of Korea Water Resources Association
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• v.36 no.5
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• pp.787-797
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• 2003

The characteristics of concentrations and loads of Total Nitrogen(T-N), Total Phosphorus(T-P), and Chemical Oxygen Demand (COD) in mountain stream water were examined from September 2000 through August 2001. The 92.5-ha study watershed in Chungbuk Province consists of 59% mixed forest and 30% coniferous forest. Streamflow was measured and water samples were collected at about 10 day intervals for dry days and at 2-6 hour intervals for a storm event at the study watershed outlet. The mean concentration of COD in streamflow for rainy days was significantly (p < 0.05) higher than for dry days. The mean concentrations of T-N and T-P in vegetation growing season (May to October) were lower than those in vegetation dormant season (November to April). Low concentrations of pollutants during vegetation growing season are likely due to the heavy demand for nutrients by the vegetation and biological activity associated with a warming of soil. The ratios of pollutants loads during storm periods to annual pollutants loads were 87% for T-N, 83% for T-p, and 87% for COD. The unit loads of pollutants for study area were estimated at 5.9 kg/ha $\cdot$ yr for T-N, 0.15 kg/ha $\cdot$ yr for T-p, and 23.9 kg/ha $\cdot$ yr for COD. The removal efficiency of pollutants in study area were 24% for T-N, 58% for T-P and 66% for COD, indicating that a study area shows water purification function.

• Journal of Korea Water Resources Association
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• v.48 no.3
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• pp.185-196
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• 2015

A conceptual watershed model HSPF (Hydrological Simulation Program-Fortran) was applied to the Hwangryong river watershed to evaluate climate change effects on pollution loads of the river. For modeling purposes, the Hwangryong river watershed was divided into 7 sub-watersheds. The model was calibrated and validated for the river discharges against the data observed in 2011 at several monitoring stations. The RCP scenarios were set up for the model simulations after being corrected by change factor method. The simulation results of the RCP 4.5 scenario indicate that the annual river discharge and concentrations of BOD, TN, TP of the Hwangryong river will continually increase during the second-half of the 21st century. As for the RCP 8.5 scenario, the simulations results imply that the pollution loads will increase during the middle of the 21st century reflecting the pattern of precipitation. Monthly distributions of the pollution loads for the RCP 4.5 and the RCP 8.5 scenarios show it will increase the most in September and February, respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.85-90
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• 2022

This study presents a Real-Time Power Quality(:PQ) Evaluation methodology that reflects customer's load characteristics. Author determined PQ as [Ideal], [Measured], [Acceptable], and evaluated measured PQ between Ideal and Acceptable by using Ideal AHP. Author determined Load as Resistance, Electric Motor, and Electronics, and evaluated PQ reflect Load characteristics. As future studies, author has plan to study 1:1 matrix and overall PQ evaluation including year-based PQ.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.258-260
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• 2008

국내의 에너지 이용 효율개선과 에너지 절약의 중요성은 갈수록 높아 가고만 있는 상황이다. 이에 국내 전력용 변압기의 평균 연간부하율을 도출하여 합리적이고 타당성 있는 고효율 변압기 기술기준안의 작성이 필요하게 되었다. 우리나라의 평균연간 부하율을 변압기 용량별, 업종별, 지역별로 구분하여 조사하였으며 이를 토대로 전력용변압기의 관련 기준안을 검토 보완하는데 활용할 수 있을 것이다. 이러한 고효율 변압기 기술기준안 수림에 의해 예상되는 기대효과는 국내 실정에 맞는 고효율 변압기의 생산 및 보급이 확대됨으로써 수용가의 전력요금절감은 물론 관련업계의 시장 경쟁력 강화 효과를 기대한 수 있을 것이다.

• Proceedings of the Korea Contents Association Conference
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• 2010.05a
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• pp.644-646
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• 2010

최근 비점오염원 제어를 위해 오염총량제(Total Maximum Daily Loads, TMDL)가 도입되었으며, 이것은 도시유역에서의 대표적 비점오염원인 합류식 하수관거 월류수(Combined Sewer Overflows, CSOs)의 발생에 대한 분석이 선행되어야 한다. CSOs를 산정하기 위한 방법으로는 두 가지가 있다. 첫째, 확률강우량 분석에 의한 유출량 모의 방법으로, 이것은 표준강우사상에 의한 연간 CSOs 산정에 국한되는 한계를 가지고 있다. 둘째, 관측 강우 자료를 이용한 장기유출모의(LOS) 방법으로, 이 방법은 장기간의 강우 자료를 이용할 경우 최근의 강우 변화 양상을 반영하기 어려우며, 반면 단기간의 강우 자료를 이용할 경우 결과에 대한 신뢰도를 보장할 수 없다. 본 연구에서는 연간 CSOs 발생량 및 오염부하량을 산정하기 위하여 강우발생모형과 Long-term Outflow Simulation 모형을 이용하였다. 본 연구를 통한 CSOs의 산정은 앞서 언급된 기존 방법들의 문제점을 해결하고자 개발되었으며, 향후 도시화에 따른 유출 변화 및 유역 물순환 변화에 대한 연구에 활용될 수 있다.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.348-350
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• 2003

본 논문에서는 태양광-풍력 복합발전시스템의 발전용량 예측을 통한 시스템 시설투자비 및 발전단가와 경제성에 대하여 분석한다. 도시지역의 일사량 및 풍속 데이터를 기초로 하여 복합발전시스템의 일일 발전량을 구하고, 수용가의 일일부하패턴과 수요부하를 고려하여 태양전지 어레이와 풍력발전기의 용량을 산정한다. 그리고 용량 산정에 따른 복합발전시스템의 초기투자비용과 연간 발전량, 연간 소요경비 등의 요소를 고려하여 총 수명가 분석법(Total Life-Cycle Cost Analysis)에 기초한 발전단가를 계산하고 잉여전력을 계통에 판매할 경우의 경제성을 평가한다.

• Korean Journal of Environmental Agriculture
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• v.18 no.1
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• pp.70-76
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• 1999

Since high concentrations of N, P, and organic C cause the excessive eutrophication in water systems, the control of nutrient export from agricultural nonpoint sources has become important. This study was conducted to estimate discharges of N, P, and organic C from a small agricultural watershed of the upper Imgo stream in Youngchun, Kyongbuk. Of the total area(1.420ha), 25% was agricultural land including paddy, upland and orchards and most of the remainder was forest. The resident population in the watershed was 194 in 80 households and relatively small numbers of livestocks including cow were raised. Mean concentrations of nutrients in the stream water were 4.95, 0.80, 6.72, 0.07 and 2.52mg/L for $NO_3-N$, $NH_4-N$, Total N, Total P and COD respectively. Annual discharges in 1997 were 28,991kg of $NO_3-N$. 3,010kg of $NH_4-N$, 37,006kg of Total N. 590kg of Total P, and 29,138kg of COD. There was a strong positive relationship between stream flow and precipitation, and also most of the nutrient discharges occurred in the rainy season (May to August). Since there was no any other industries in the watershed, agricultural practices and sewage from the resident households, forest runoff and livestock wastes were the major sources of NPS discharges. A combination of management options, including management of soil erosion and fertilizer application, could lead to reductions in nutrient exports.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.1
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• pp.48-72
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• 1985

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.278-284
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• 2023

Recently, a closed-type plant factory has been receiving attention as a advanced agricultural method. It has diverse advantages such as climate-independence, high productivity and stable year-round production. However, high energy cost caused by environmental control system is considered as a challenges of a closed-type plant factory. In order to reduce the energy cost, investigation about energy load which is directly connected to energy consumption needs to be conducted. In this study, energy load changes of a plant factory have been analytically analyzed according to the environmental changes. The target plant factory was a lettuce growing container farm. Firstly, the impact of photoperiod, set temperature and relative humidity change were examined. Under the climate condition of Daejeon in South Korea, increase of photoperiod and set temperature rose a yearly energy demand of a container farm. However, increase of set relative humidity decreased a yearly energy demand. Secondly, the climate environment effect was compared by investigating the energy demand under 9 different climate conditions. As a result, the difference between maximum and minimum value of the yearly energy demand showed 21.7%. Lastly, sensitivity analysis of each parameter (photoperiod, set temperature and relative humidity) has been suggested under 3 different climate conditions. The ratio of heating and cooling demand was varied depending on the climate, so the effect of each parameter became different.