• 대한전기학회논문지
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• 제35권5호
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• pp.193-198
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• 1986

In this paper, 1-168 hours ahead load prediction algorithm is developed for power system economic weekly operation. Total load is composed of three components, which are base load, week load and weather-sensitive load. Base load and week load are predicted by moving average and exponential smoothing method, respectively. The days of moving average and smoothing constant are optimally determined. Weather-sensitive load is modeled by linear form. The paramiters of weather load model are estimated by exponentially weighted recursive least square method. The load prediction of special day is very tedious, difficult and remains many problems which should be improved. Test results are given for the day of different types using the actual load data of KEPCO.

• 한국항공운항학회지
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• 제31권3호
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• pp.93-102
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• 2023

Jeju International Airport is characterized by the occurrence of low-level windshear due to its location, surrounding terrain, and its weather characteristics. Especially the low-level windshear accompanied by tailwinds on both sides of the runway i.e., bidirectional tailwind, is a hazardous weather phenomenon with unique characteristics that are difficult to find at any other airports. This study focuses on bidirectional tailwind occurrence at Jeju International Airport in 2020-2021. As a result, characteristic pressure patterns of the types that cause bidirectional tailwind was identified as it was possible to categorize strong wind types such as 1) strong southwest wind, 2) strong east wind, and 3) strong northwest wind, which do not cause bidirectional tailwind, and wind direction variation types such as 4) bidirectional tailwind, and 5) south wind followed by southwest wind, which cause bidirectional tailwind. The results of this study are expected to contribute to improving aviation safety by enabling aviation operators to predict and take appropriate safety measures based on their understanding of the causes and characteristics of bidirectional tailwind.

• 한국물환경학회지
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• 제28권2호
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• pp.285-291
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• 2012

Generally, the rainfall and the influent of wastewater treatment plants (WWTPs) have strong relationship at the case of combined sewers. With the fact that the influent variations in terms of quantity and sewage quality is the most common and significant disturbance, the impact factor to the characteristics of sewage should be searched for. In this paper, the relationship between weather conditions such as humidity, temperature and rainfall and influent flowrate and contaminant concentration was analysed using factor analysis. Additionally, 3 influent types were deduced using cluster analysis and the distributions of operational variables were compared to the each groups by one-way ANOVA. The applied dataset were clustered to three groups that have the similar weather and influent conditions. These different conditions can cause the different operating conditions at WWTPs. That is, the Group 1 is for the condition with high humidity and rainfall, so DO concentration in the reactor was very high but MLSS concentration was very low because of too large flowrate. However, the Group 3 is classified to the case having low humidity, temperature, and rainfall, therefore, the SRT was the longest and the SVI was the highest due to the worst settleability in the winter for a year.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권3호
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• pp.146-152
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• 2004

Cost effective simulation schemes for Wind Power Generation Systems (WPGS) considering wind turbine types, generators and load capacities have been strongly investigated by researchers. As an alternative, a true weather condition based simulation method using a real-time digital simulator (RTDS) is experimented in this paper for the online real-time simulation of the WPGS. A stand-alone WPGS is, especially, simulated using the Simulation method for WPGS using Real Weather conditions (SWRW) in this work. The characteristic equation of a wind turbine is implemented in the RTDS and a RTDS model component that can be used to represent any type of wind turbine in the simulations is also established. The actual data related to weather conditions are interfaced directly to the RTDS for the purpose of online real-time simulation of the stand-alone WPGS. The outcomes of the simulation demonstrate the effectiveness of the proposed simulation scheme. The results also signify that the cost effective verification of efficiency and stability for the WPGS is possible by the proposed real-time simulation method.

• 수산해양기술연구
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• 제48권1호
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• pp.82-90
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• 2012

Four different buildings having various wall construction are analyzed for the effect of wall mass on the thermal performance and inside building air and wall temperature transient and also for calculating the energy consumption load. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one-dimensional, linear, partial differential equations is obtained using the Laplace transform method, Bromwich and modified Bromwich contour method. A simple dynamic model using steady state analysis as simplified methods is developed and results of energy consumption loads are compared with results obtained using the analytical solution. Typical Meteorological Year data are processed to yield hourly average monthly values. This study is conducted using weather data from two different locations in Korea: Daegu having severe weather in summer and winter and Jeju having mild weather almost all year round. There is a significant wall mass effect on the thermal performance of a building in mild weather condition. Buildings of heavyweight construction with insulation show the highest comfort level in mild weather condition. A proportional controller provides the higher comfort level in comparison with buildings using on-off controller. The steady state analysis gives an accurate estimate of energy load for all types of construction. Finally, it appears that both mass and wall insulation are important factors in the thermal performance of buildings, but their relative merits should be decided in each building by a strict analysis of the building layout, weather conditions and site condition.

• 대한교통학회지
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• 제28권1호
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• pp.157-163
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• 2010

기상상태에 따른 교통사고발생 및 사고심각도는 밀접한 관계가 있음이 잘 알려져있다. 최근고속도로에서 교통 안전성 평가지표 및 시스템의 개발은 사고 치명도를 줄이고자 접근하는 것이다. 본 연구에서는 도로선형 요소와 기상 상태를 고려한 교통사고 영향 요인을 분석하여 규명하고자 한다. 기상상태요인과 도로요인과의 교통사고 발생 관계를 규명하기 위하여 과거사고이력자료를 이용하여 판별분석을 수행하였으며 눈, 맑음, 비, 안개, 흐림의 5가지 유형에 대해 도로 구성요소인 노면과 경사도를 통해 구분하였다. 그 결과 콘크리트 노면과 하향경사 3%이상인 구간에서 각 기상상태 별 사고영향이 다르며 이러한 주행환경에서는 시정거리의 감소와 정지거리의 증가가 주행 위험요인으로 발생할 수 있는 구간이다. 본 연구에서는 기상악화시 콘크리트 노면과 하향경사가 형성된 구간이 평상시 보다 주행시 주의를 필요로 하는 구간임을 분석하였으며 분류함수의 계수 비교를 통해 영향지표를 개발하였다.

• 한국환경과학회지
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• 제28권1호
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• pp.85-97
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• 2019

Meteorological factors and air pollutants are associated with respiratory diseases, and appropriate use of weather and air quality information is helpful in the management of patients with such diseases. This study was performed to investigate both the utilization of weather and air quality information by, and the needs of, patients with respiratory diseases. Questionnaires were administered to 112 patients with respiratory diseases, 60.7% of whom were female. The rates of bronchial asthma and chronic obstructive pulmonary disease among patients were 67.0% and 10.7%, respectively. The majority of subjects (90%) responded that prevention was important for respiratory disease management and indicated that they used weather and air quality information either every day or occasionally. However, respondents underestimated the importance of weather and air quality information for disease management and were unaware of some types of weather information. The subjects agreed that respiratory diseases were sensitive to weather and air quality. The most important weather-related factors were diurnal temperature range, minimum temperature, relative humidity, and wind, while those for air quality were particulate matter and Asian dust. Information was gleaned mainly from television programs in patients aged 60 years and older and from smartphone applications for those below 60 years of age. The subjects desired additional information on the management and prevention of respiratory diseases. This study identified problems regarding the utility of weather and air quality information currently available for patients with respiratory diseases, who indicated that they desired disease-related information, including information in the form of action plans, rather than simple health- and air quality-related information. This study highlights the necessity for notification services that can be used to easily obtain information, specifically regarding disease management.

• 한국유통학회지:유통연구
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• 제17권5호
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• pp.59-83
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• 2012

농업은 타 산업 대비 기상환경에 큰 영향을 받는 산업이다. 기상 상태는 수시로 변화하며, 지역에 따라 서로 다른 특성을 보인다. 또한 이러한 지역적 특성은 그 지역의 농산물의 재배환경에도 영향을 주게 된다. 이러한 특성 때문에 기상이 농업에 미치는 영향에 대해서는 그동안 많은 연구가 이루어져 왔다. 그러나 대부분의 연구가 농작물의 생산에만 초점이 맞춰져, 농작물이 생산에서 유통과정에서 기상요인이 미치는 영향을 통합적으로 살펴본 연구는 매우 부족한 실정이다. 본 연구에서는 대표적인 농작물인 배추를 중심으로, 기상요인이 농산물 유통에 미치는 영향을 분석하였다. 배추는 우리 식탁에서 빼놓을 수 없는 식재료이면서, 기상 변화에 영향을 많이 받는 품목이다. 기상이변으로 배추의 가격이 폭등하게 되면 서민가계에 직접적으로 영향을 받게 된다. 이러한 관점에서 생산과 유통단계별로 기상요인이 배추에 어떠한 영향을 미치는지를 분석하였다. 본 연구에서는 배추의 재배유형별 거래량과 거래가격에 대한 실거래 데이터와 재배시기와 판매지역에 따른 기상요인에 대한 자료를 수집하여, 배추의 도매시장 거래량과 거래가격에 영향을 미치는 기상요인을 파악하고자 하였다. 연구 결과 배추의 생산지 기상요인보다 판매지역 기상요인의 영향이 배추의 거래량과 거래가격에 상대적으로 더 큰 영향을 미치는 것으로 확인되었다. 본 연구의 결과를 바탕으로, 향후 기상요인을 고려한 출하시기와 반입량에 대한 정책적 가이드라인을 제시하여 농산물 수급에 대한 선제적이고 체계적인 대응체제가 구축된다면, 기상변화에 민감한 농산물의 가격안정에 기여할 수 있을 것으로 기대된다.

• 한국농림기상학회지
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• 제16권4호
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• pp.389-395
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• 2014

이 단보는 농업기상재해 조기경보시스템을 전국적인 현업서비스로 정착시키기 위한 초기단계 기술구현에 관해 설명한다. 먼저 집수역별 기상특보 서비스는 기상청에서 발표하는 기존 150개 시군단위 특보발생 여부를 공간통계기법에 의해 810개 집수역 단위의 순차적인 위험도로 표현하였다. 두번째로 집수역별 지발성 재해경보 서비스는 76개 정규기상관측소의 일별 자료를 토대로 810개 집수역의 중장기 경과기상을 주단위로 감시하여 같은 기간의 기후학적 평년기상에 대비한 현 시점의 만성적 재해위험을 상대지수로 표현하였다. 마지막으로 조기경보서비스 시범지역인 섬진강 하류유역 내 자원농가에 대해여 재해위험을 필지별로 산출하여 개별적으로 전달하기 위한 기반을 마련하였다. 이들 세 종류의 정보를 국토교통부 공간정보 오픈 플랫폼 배경지도 위에 전국 집수역 및 시범지역 내 농장단위 재해위험 레이어로 중첩시켜 준실시간 지도 서비스를 구축하였다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.64-71
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• 2017

Considering the volatility, intermittent and random of photovoltaic (PV) generation systems, accurate forecasting of PV power output is important for the grid scheduling and energy management. In order to improve the accuracy of short-term power forecasting of PV systems, this paper proposes a prediction model based on environmental factors and support vector machine optimized by genetic algorithm (GA-SVM). In order to improve the prediction accuracy of this model, weather conditions are divided into three types, and the gray correlation coefficient algorithm is used to find out a similar day of the predicted day. To avoid parameters optimization into local optima, this paper uses genetic algorithm to optimize SVM parameters. Example verification shows that the prediction accuracy in three types of weather will remain at between 10% -15% and the short-term PV power forecasting model proposed is effective and promising.