• 한국산업정보학회논문지
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• 제18권3호
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• pp.35-46
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• 2013

국내 전력 수요량 예측을 위한 정확한 분석 모델을 개발하기 위하여 고차원 데이터 군집 분석에 적합한 차원 축소 개념의 부분공간 군집 기법과 SMO 분류 기법을 결합한 전력 수요 패턴 예측 방법을 제안하였다. 전력 수요 패턴 예측은 무선부하감시 데이터 뿐 아니라 소지역 단위의 센서스 정보를 통합하여 시간대별 전력 부하 패턴 분석과 인구통계학 및 지리학적 특성 분석이 가능하다. 서울지역 대상의 센서스 정보 및 전력 부하를 이용한 소지역 전력 수요 패턴 예측 결과 총 18개의 특성 군집을 구성하였으며, 전력 수요 패턴 예측 정확도는 약 85%를 보였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권1호
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• pp.39-49
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• 2013

This paper presents a method of improving the performance of a day-ahead 24-h load curve and peak load forecasting. The next-day load curve is forecasted using radial basis function (RBF) neural network models built using the best design parameters. To improve the forecasting accuracy, the load curve forecasted using the RBF network models is corrected by the weighted sum of both the error of the current prediction and the change in the errors between the current and the previous prediction. The optimal weights (called "gains" in the error correction) are identified by differential evolution. The peak load forecasted by the RBF network models is also corrected by combining the load curve outputs of the RBF models by linear addition with 24 coefficients. The optimal coefficients for reducing both the forecasting mean absolute percent error (MAPE) and the sum of errors are also identified using differential evolution. The proposed models are trained and tested using four years of hourly load data obtained from the Korea Power Exchange. Simulation results reveal satisfactory forecasts: 1.230% MAPE for daily peak load and 1.128% MAPE for daily load curve.

• 한국태양에너지학회 논문집
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• 제38권1호
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• pp.1-11
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• 2018

In this work, we propose weather prediction models to estimate hourly outdoor temperatures and solar irradiance in the next day using forecasting information. Hourly weather data predicted by the proposed models are useful for setting system operating strategies for the next day. The outside temperature prediction model considers 3-hourly temperatures forecasted by Korea Meteorological Administration. Hourly data are obtained by a simple interpolation scheme. The solar irradiance prediction is achieved by constructing a dataset with the observed cloudiness and correspondent solar irradiance during the last two weeks and then by matching the forecasted cloud factor for the next day with the solar irradiance values in the dataset. To verify the usefulness of the weather prediction models in predicting a short-term building load, the predicted data are inputted to a TRNSYS building model, and results are compared with a reference case. Results show that the test case can meet the acceptance error level defined by the ASHRAE guideline showing 8.8% in CVRMSE in spite of some inaccurate predictions for hourly weather data.

• 산업경영시스템학회지
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• 제43권4호
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• pp.76-83
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• 2020

Postal logistics organizations are characterized as having high labor intensity and short response times. These characteristics, along with rapid change in mail volume, make load scheduling a fundamental concern. Load analysis of major postal infrastructures such as post offices, sorting centers, exchange centers, and delivery stations is required for optimal postal logistics operation. In particular, the performance of mail traffic forecasting is essential for optimizing the resource operation by accurate load analysis. This paper addresses a traffic forecast problem of postal parcel that arises at delivery stations of Korea Post. The main purpose of this paper is to describe a method for predicting short-term traffic of postal parcel based on self-similarity analysis and to introduce an application of the traffic prediction model to postal logistics system. The proposed scheme develops multiple regression models by the clusters resulted from feature engineering and individual models for delivery stations to reinforce prediction accuracy. The experiment with data supplied by main postal delivery stations shows the advantage in terms of prediction performance. Comparing with other technique, experimental results show that the proposed method improves the accuracy up to 45.8%.

• 생물환경조절학회지
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• 제2권2호
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• pp.99-109
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• 1993

Cooling of nutrient solution is essential to improve the growth environment of crops in hydroponic culture during summer season in Korea. This study was carried out to provide fundamental data for development of the cooling system satisfying the required cooling load of nutrient solution in hydroponic greenhouse. A numerical model for prediction of the cooling load of nutrient solution in hydroponic greenhouse was developed, and the results by the model showed good agreements with those by experiments. Main factors effecting on cooling load were solar radiation and air temperature in weather data, and conductivity of planting board and area ratio of bed to floor in greenhouse parameters. Using the model developed, the design cooling load of nutrient solution in hydroponic greenhouse of 1,000$m^2$(300pyong) was predicted to be 95,000 kJ/hr in Suwon and the vicinity.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.141-146
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• 2000

Crack closure and growth behavior of physically short fatigue cracks under random loading are investigated by performing narrow- and wide-band random loading tests for various stress ratios. The importance of the crack closure phenomenon is examined by predicting the growth lives of short cracks using obtained crack opening behavior. Artificially prepared two-dimensional, short through-thickness cracks are used. The crack opening load of short cracks is much lower under random loading than under constant-amplitude loading corresponding to the largest load cycle in a random load history. This result indicates that the largest load cycle in a random load history has an effect to enhance crack opening of short cracks. Most of the life prediction ratios are within the factor of 2 scatter band except several data at very short crack sizes, indicating that crack growth predictions based on the measured crack opening data are excellent. From the results obtained in this study, it can be concluded that crack closure is the primary factor governing fatigue crack growth of short cracks under random loading as well as under constant-amplitude loading.

• 한국멀티미디어학회논문지
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• 제12권9호
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• pp.1242-1251
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• 2009

유비쿼터스 환경에서 데이터 스트림 관리 시스템(Data Stream Management System: DSMS)은 수많은 센서로부터 생성되는 대량의 데이터 스트림을 처리한다. 기존의 시스템은 처리 능력 이상의 데이터 스트림이 입력되면 데이터의 일부를 제거하여 적정 부하를 유지하는 부하 제한 기법(Load Shedding)을 사용한다. 부하 제한 기법은 입력되는 데이터의 일부를 의도적으로 손실하여 데이터 완전도(Data Completeness)가 감소하기 때문에 처리 결과의 신뢰도 또한 감소한다. 따라서 본 논문에서는 시스템 처리 능력 이상의 데이터 스트림 입력 시 데이터 완전도 보장을 위한 과부하 예측 부하 분산 기법을 제안한다. 제안 기법은 데이터 손실이 예상되는 부하 시점을 미리 예측하고 예측된 부하 시점에 도달 시 부하를 분산하여 데이터 손실을 감소시킨다. 본 논문에서는 기존의 부하 제한 기법과의 비교 실험을 통해 제안 기법의 성능을 평가한다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.382-389
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• 2002

Recently, auger-drilled piling has been widely used in urban area to reduce the air pollution and noise. But this construction method that its basic theory was introduced from Japan may be changed depending on the each piling company and construction field condition. Therefore, the design code and management method for auger-drilled piling is not defined yet. Especially, the lack of research on the bearing capacity of auger-drilled piling leads to the absence of rational bearing capacity prediction equation. This paper presents the optimum design code and economical construction method of the auger-drilled piling by proposing the new bearing capacity prediction equation based on the site specific soil types and construction conditions. In this paper, existing bearing capacity prediction equations and current pile load tests were compared. And the end bearing capacity and skin friction characteristics were also analyzed by comparing the results of CAPWAP. From the results of analysis, a reliable bearing capacity prediction equation considered soil types is proposed.

• 한국생산제조학회지
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• 제8권5호
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• pp.108-114
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• 1999

The thermal environmental chamber has been using in maintaining weather condition keeping thermal capacity under heating and cooling load fluctuation and for the performance testing of cooling system or air-conditioner on artificial envi-ronment. In ordder to make the various environmental conditions in the thermal environmental chamber the proper cooling system is necessary to eliminate the heating load produced inside the chamber and to maintain the designed environmental condition. For this reason the optimal design of cooling system and the prediction of performance is also required. This paper describes the prediction of performance of cooling system in the thermal environmental chamber with the capacity of 37,000kcal/hr which is developed for the test of performance in heating mode of heat pump system, In the results this paper is trying to develop simulation program on the base of mathematical models and which can be applied effectively to the optimal design of cooling system and prediction of performance to the inside and outside change of envi-ronmetal load.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.648-653
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• 2007

In this study, we have generated fatigue load spectrum that is using to prediction of life time for the helicopter rotor blades. We derive utility helicopter missions for the sake of generating load spectrum. Helix and Felix are standard loading sequences which relate to the main rotors of helicopters with articulated and semi-rigid rotors respectively. We got scale factors which is applied to specific case and it did be obtained through the finite element analysis tools. The fatigue life of the rotor blade is estimated by using MSC/Fatigue. We suggest that generated our fatigue load spectrum in conjunction with small utility helicopter should use to rotor blade fatigue test of the korea helicopter program.