• Computers and Concrete
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• 제6권5호
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• pp.403-419
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• 2009

Short column effect is cause to failure of columns which may result in severe damages or even collapse during earthquakes. The scope of the study is mainly to reveal the effect of short column on the holistic behaviour of the buildings. The nonlinear analysis of 31 different frame buildings containing short column problem are carried out using finite element method. The finite element models were selected by 2 bays and 3 stories. Since the short columns are generally seen in the first storey of the buildings, in the study, they are only constructed in the same storey. The adverse effect of the short column on the response of buildings was shown in terms of the total load factor and displacement capacity of building. The response of buildings in terms of ground storey displacements is presented in figures and discussed. It is revealed that if the window openings are constructed along the bays, the total load capacity is decreased 85% compared with reference model in which all of bays are filled with infill walls.

• 설비공학논문집
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• 제22권4호
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• pp.241-247
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• 2010

This study aims to investigate and improve the present state of technical standard on building mechanical system in Korea. At this point be tormented the energy depletions are big problem on the rise. Building mechanical system is configured air conditioning, sanitation, urban equipment. In the design of equipment, installation, maintenance, applies to all devices in the field of industrial equipment and general engineering equipment field are within bounds to say that all of the equipment field. However, domestic technology level is still fly short of international standards in architecture, we spent much energy. Because of this, find the current situation and identify the problems look up ways to improve them.

• 한국물환경학회지
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• 제36권5호
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• pp.431-444
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• 2020

The relationship between dam construction and water quality has recently come to be considered an important issue. A dam is a physical factor which causes changes to the river system around it. Considering these points, this study was conducted to obtain basic data by analyzing the relationship between water level fluctuations and water quality parameters in the short-term. In terms of methodology, the new construction of the Yeongju Dam (M5) in 2016 was divided into Stage 1 as the lotic system and Stage 2 as the lentic system, with four years in each period, and the water level fluctuations and water quality were analyzed using official data. As a result of this study, M5, a stagnant area in which organic matter and nutrients accumulate, was found to be an important factor in water quality management. In addition, the water level changed rapidly (0.9±0.2 m → 10.9±7.1 m) as the river environment condition was converted from the lotic system to the lentic system. In addition, water quality parameters such as BOD, COD, TOC, and Chl-a significantly changed in the short-term. Further, since the transport of organic matter and nutrients occurred well in the lotic system, sedimentation was expected to be dominant in the lentic system. Therefore, it was determined that when the river flow is blocked, autochthonous organic matter is an important factor for long-term water quality management in the future. This process can increase the trophic state of the water body. As a result of this study, the TSI_KO value was converted from mesotrophic in Stage 1 to eutrophic in Stage 2. Eventually, short-term changes in the river environment will affect not only changes in water level but also changes in water quality. Thus, a comprehensive and strategic approach is needed for long-term water quality management in the future.

• 한국수자원학회논문집
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• 제53권3호
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• pp.225-236
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• 2020

유역 상류의 소규모 산지 유역 또는 도시 배수분구 정도의 도시 유역은 지체시간이 수 십 여분에 불과하기 때문에 우량계만으로는 대응에 필요한 충분한 예측 선행시간을 확보하기 어렵다. 도시 및 소규모 산지 유역에서와 같이 지체시간이 짧은 유역에서 발생하는 돌발홍수는 더 이상 우량계만으로 예보가 불가능하다. 도달시간이 짧은 도시 및 산지에서는 지체시간 외에 강수 예측을 통한 홍수예보 선행시간을 확보하는 것이 매우 중요하다. 한강홍수통제소에서는 강우레이더 강우강도를 초단기 예측 모델인 Mcgill Algorithm for Precipitation-nowcast by Lagrangian Extrapolation(MAPLE) 알고리즘의 입력 자료로 활용하여 초단기 예측 강수 자료를 생산하고 있다. 한국건설기술연구원의 돌발홍수연구센터는 한강홍수통제소에서 생산하고 있는 초단기 예측 강수 자료를 입력 자료로 하여 돌발홍수 예측 시스템을 구축하였고 2019년부터 동네규모의 1시간 전 돌발홍수정보를 제공하고 있다. 본 연구에서는 돌발홍수연구센터에서 구축한 돌발홍수 예측 시스템을 설명하고 2019년도에 발생한 수재해 사례를 분석하여 전국 도시·산지·소하천 돌발홍수 예측 시스템의 예측 정확도를 검증하였다. 돌발홍수 예측 시스템의 정확도 검증에는 총 31개의 수재해 사례를 적용하였고 예측 정확도는 Probability of Detection (POD) 기준으로 90.3%로 매우 높게 나타났다.

• 설비공학논문집
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• 제15권5호
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• pp.422-431
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• 2003

Theory of the building heat transfer is generally limited to the heat flux to the surfaces of windows and walls, which influences the indoor climate of a building, in the field of architectural environmental engineering. While the heat flux from the buildings to their environment has been considered in the viewpoint of urban climate, its conventional theory have been rarely examined. The purpose of this study is to propose a building-urban heat transfer model for defining the relation between the building and the urban climate by extending the building heat transfer model. In this study, the extended building heat transfer model, where response factor method is used, is established on the urban space and the indoor space by the boundary of building envelopes. Computer simulation (HASP/ACLD) is conducted on the subjected urban area by the established building-urban heat transfer model. As a result it is logically proved that the short waves of solar radiation, which interact with long Waves of radiation from the buildings and the earth, increase the urban air temperature ana buildings largely influence on the urban climate.

• Computers and Concrete
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• 제7권6호
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• pp.523-532
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• 2010

If an infill wall in a reinforced concrete frame is shorter than the column height and there is no initial gap between the column and the infill wall, the short column effect can occur during an earthquake shaking. This form of damage is frequently observed in many earthquake-damaged buildings all around the world and especially in Turkey. In this study, an effective method, which consists of placing additional infill wall segments surrounding the short column, to prevent this type of failure is examined. The influence of adding infill wall in the reduction of the shear force in the short column is also investigated. A parametric study is carried out for one-storey infilled frames with one to five bays using the percentage of the additional infill wall surrounding the short column and the number of spans as the parameters. Then the investigation is extended to a case of a multistorey building damaged due to short column effect during the 1998 Adana-Ceyhan earthquake in Turkey. The results show that the addition of the infill walls around the potential short columns is an effective way to significantly reduce the shear force.

• 전기전자학회논문지
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• 제22권3호
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• pp.672-679
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• 2018

Recently, microgrid (MG) has been proposed as one of the most critical solutions for various energy problems. For the optimal and economic operation of MGs, it is very important to forecast the load profile. However, it is not easy to predict the load accurately since the load in a MG is small and highly variable. In this paper, we propose an artificial neural network (ANN) based method to predict the energy use in campus buildings in short-term time series from one hour up to one week. The proposed method analyzes and extracts the features from the historical data of load and temperature to generate the prediction of future energy consumption in the building based on sparsified K-means. To evaluate the performance of the proposed approach, historical load data in hourly resolution collected from the campus buildings were used. The experimental results show that the proposed approach outperforms the conventional forecasting methods.

• Structural Engineering and Mechanics
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• 제64권2호
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• pp.173-181
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• 2017

This paper analyzes the influence of the construction process on short- and long-term deflections on a reinforced concrete structure poured on-site by a portable industrialized system. A parametric analysis was carried out by the Finite Elements Method (FEM) that considered: a) type of construction process with reshoring or clearing (partial striking); b) the number of successively shored floors and c) the number of shores used on each floor. All three factors were especially important for the values of short- and long-term deflections, which were highest in the reshoring processes with the lowest number of successively shored floors and the lowest number of shores per floor. Deflections obtained were compared with the limits laid down by ACI 318-14 and as calculated by this code's simplified method. The long-term deflections were seen to be almost double than those obtained by applying the ACI 318-14 code's simplified method and in some cases these deflections were above the established limits. It can thus be concluded that the load history of a building under construction should be taken into account in order to satisfy a structure's in-service conditions and durability.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.299-303
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• 2011

This paper proposes a novel sensorless maximum power point tracking (11PPT) algorithm for PV systems. The method is based on dividing the operating time into several intervals in which the PV terminals are short circuited in one interval and the calculated short-current of the PV is obtained and used to determine the optimum operating point where the maximum output power can be obtained. The proposed MPPT algorithm has been introduced into a current-controlled boost converter whose duty ratio is controlled to the maintain MPP condition. The same sequence is then repeated regularly capturing the PV maximum power. The main advantage of this method is eliminating the current sensor. Meanwhile, this MPPT algorithm reduces the power oscillations around the peak power point which occurs with perturbation and observation algorithms. In addition, the total cost will decrease by removing the current sensor from the PV side. Finally, simulation results confirm the accuracy of the proposed method.

• 한국태양에너지학회 논문집
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• 제39권5호
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• pp.41-52
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• 2019

The purpose of the work is to develop a simple solar irradiance prediction model using a deep learning method, the LSTM (long term short term memory). Other than existing prediction models, the proposed one uses only the cloudiness among the information forecasted from the national meterological forecast center. The future cloudiness is generally announced with four categories and for three-hour intervals. In this work, a daily irradiance pattern is used as an input vector to the LSTM together with that cloudiness information. The proposed model showed an error of 5% for learning and 30% for prediction. This level of error has lower influence on the load prediction in typical building cases.