• Title/Summary/Keyword: Regional prediction

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Inflow Forecasting for Reservoir Operation using Artificial Neural Network with RDAPS (인공신경망과 RDAPS 자료를 이용한 유입량 예측)

  • Choi, Gi-An;Lee, Kyoung-Joo;Kim, Tae-Soon;Heo, Jun-Haeng
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.23-26
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    • 2009
  • 효과적인 저수지 운영을 위해 가장 중요한 절차는 저수지 유입량을 적절하게 모의하는 것이다. 실시간 저수지 운영의 경우 기존의 물리적인 강우-유출현상에 기초한 수학적인 모형을 이용해서 유입량을 예측하는데 한계가 있으므로 인공신경망과 같이 자료의 특성에 기반한 모형이 효율적인 대안이 될 수 있다. 본 연구에서는 인공신경망(Artificial neural network, ANN)을 이용하여 실시간 저수지 운영을 위해 현재시간을 기준으로 3시간 후, 6시간 후, 9시간 후, 12시간 후의 유입량을 예측하였다. 본 연구의 대상지역은 한강수계의 화천댐 유역으로 기상청 수치예보자료인 RDAPS(Regional Data Assimilation and Prediction System)자료 중에서 강우예측자료를 사용하였다. RDAPS 강우예측자료를 이용한 예측값 결과와 비교하기 위해 지점 강우자료를 사용하였으며, 이 지점 강우자료는 화천댐 유역에 있는 AWS, 기상청, 국토해양부의 지점자료을 이용하였다. RDAPS 강우예측값만을 이용한 유입량 예측결과가 과거 12시간 강우 누적값을 이용한 유입량 예측값과 비슷한 정확도를 가지는 것을 알 수 있었으며, 자료의 효율적인 취득을 고려해야만 하는 실시간 운영의 경우, RDAPS 강우예측자료와 인공신경망을 이용한 모형이 충분히 효과적인 대안이 될 수 있음을 알 수 있다.

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Assessment on the Application of Short-Term Forecast Rainfall for Dam Operation on Flooding Season (홍수기 댐 운영을 위한 단기 예측강우의 적용성 평가)

  • Byun, Dong-Hyun;Kim, Jin-Hoon;Bae, Deg-Hyo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.42-46
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    • 2009
  • 최근 국지적 집중호우로 인한 인명과 재산피해가 증가하고 있는 실정이며 이러한 피해를 경감하기 위한 하나의 방책으로써 홍수예경보 시스템 구축의 관심이 늘어나고 있다. 그러나, 기존의 홍수예측 시스템은 강우관측치를 모형의 입력 자료로 홍수유출을 계산하는데, 집중호우와 같은 악기상 조건에서는 관측강우자료를 이용한 유출해석 결과를 이용하여 홍수예경보 시스템을 운영할 경우 예방 대응시간의 부족으로 인해 방재 효율성이 떨어지는 한계성을 지니고 있다. 이와 같은 상황에서 정확한 기상예보를 활용한 기상-수자원 연계기법을 개발하여 홍수예경보 시스템에 적용한다면 악기상 감시예측기술의 향상과 더불어 재해의 방지차원에서 매우 유용한 대책이 될 뿐만 아니라 그 활용성을 극대화 시킨다면 수자원분야의 치수기 홍수예측 등에 매우 유용하게 활용될 수 것이다. 이에 본 연구에서는 모형의 입력으로 활용되는 단기 예측강우의 국내 적용성 여부를 검토하기 위해 30km의 공간해상도를 가진 단기지역예보모델인 RDAPS(Regional Data Assimilation and Prediction System) 예측강우 자료에 대하여 수문학적 정확도 분석을 수행하였으며, 예측강우의 정확도 향상을 위한 편차보정 방법을 개발 적용하였다. 또한 산정된 예측강우를 바탕으로 HEC-1 모델과의 연계방안을 제안하고 이를 이용하여 한강수계 주요 댐유역의 예측유입량을 산정, 댐 운영에 대한 적용성을 판단하고자 한다.

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A Study of Forecast System for Clear-Air Turbulence in Korea Part I: Korean Integrated Turbulence Forecasting Algorithm (KITFA) (한국의 청천난류 예보 시스템에 대한 연구 Part I: 한국형 통합 난류 예측 알고리즘)

  • Jang, Wook;Chun, Hye-Yeong;Kim, Jung-Hoon
    • Atmosphere
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    • v.19 no.3
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    • pp.255-268
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    • 2009
  • Based on the pilot reports (PIREPs) collected in South Korea from 2003 to 2008 and corresponding Regional Data Assimilation and Prediction System (RDAPS) analysis data of 30 km resolution, we validate the Korean Integrated Turbulence Forecasting Algorithm (KITFA) system that predicts clear-air turbulence (CAT) above the Korean peninsula. The CATs considered in this study are the upper level (higher than 20000 ft) turbulence excluding convectively induced turbulences. In the KITFA system, there are two main processes for predicting CATs: to select CAT indices and to determine their weighting scores. With the PIREPs observed for much longer period than those used in the current operational version of the KITFA system (March 4-April 8 of 2002), three improvable processes of the current KITFA system, re-calculation of weighting scores, change of method to calculate weighting scores, and re-selection of CAT indices, are tested. The largest increase of predictability is presented when CAT indices are selected by using longer PIREP data, with the minor change using different methods in calculation of weighting scores. The predictability is the largest in wintertime, and it is likely due to that most CAT indices are related to the jet stream that is strongest in wintertime. This result suggests that selecting proper CAT indices and calculating their weighting scores based on the longer PIREPs used in this study are required to improve the current KITFA.

Development of PSCF Model and Determination of Proper Values of Control Parameters (PSCF 모형의 개발과 제어변수의 결정)

  • Cheong, Jang-Pyo;Lee, Seung-Hoon
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.1
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    • pp.135-143
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    • 2006
  • The objective of this study is to develop PSCF (potential source contribution function) program and determine the optimal values of control parameters to enhance the prediction of PSCF modeling. This study provides an important information and methodologies that can be used to get better results of locating influencing sources, especially unknown and fugitive sources. To determine proper values of control parameters in PSCF model, the diagnostic assessment on the results obtained by the various input conditions was carried out. PSCF model has created and improved from version 1.0 to version 7.0 since 200 I and the measured data (at least > 100) of receptor, and the values of control input parameters should be arranged and determined to obtain reliable results in PSCF modeling. The size of modeling domain must be determined to include enough trajectories to get reliable results. And the size of grid is recommended to be 2.5 5 degrees for global scale, 0.2 1 degrees for regional scale and 0.05 degree for local scale.

An Analytical Study to Reduce Plastic Deformation in Intersection Pavements (교차로 포장 소성변형 저감을 위한 해석적 연구)

  • Choi, Jun-Seong;Lee, Kang-Hun;Kwon, Soo-Ahn;Jeong, Jin-Hoon
    • International Journal of Highway Engineering
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    • v.14 no.4
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    • pp.29-36
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    • 2012
  • PURPOSES : Plastic deformation is frequently made in intersection asphalt pavement at its early age due to deceleration and stoppage of vehicles. This study has been performed to provide a mechanistic basis for reasonable selection of paving method to minimize the plastic deformation at intersection. METHODS : Pavement layer, temperature, traffic volume of the intersections managed by the Daejeon Regional Construction and Management Administration were collected to calculate asphalt dynamic modulus with pavement depth by using a prediction equation suggested by the Korean pavement design guide. Performance of ordinary dense-graded asphalt pavement, polymer modified asphalt pavement, and fiber reinforced asphalt pavement was analyzed by finite element method and the results were used in a performance model to predict the plastic deformation. RESULTS : In aspect of performance, the three paving methods were usable under low traffic while the fiber reinforced asphalt pavement was the most suitable under heavy traffic. CONCLUSIONS : Reasonable paving method suitable for traffic characteristics in the intersection might be decided by considering economic feasibility.

Excess Noise Map for Environmental Standard and Assessment of Noise with Using GIS Data (GIS 자료를 이용한 초과소음지도 작성과 소음 평가)

  • Ko, Joon-Hee;Lee, Byung-Chan;Lim, Jae-Serk;Park, Su-Jin;Chang, Seo-Il
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.10
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    • pp.1075-1082
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    • 2009
  • Using GIS data of C-si as basic data when making noise map of road traffic, we estimated exactly the noise excess areas and consequently suggested the population and the area exposed to road traffic noise accurately. We made 3D noise map to assess regional distribution of noise quantitatively. The noise map consists of noise prediction model based on data base such as traffic volume and speed changes for estimating quantitatively the noise and 3D urban space model which includes locations of noise sources, 3D buildings, topography and roads. We made noise standard map according to land use conditions and compared this map to road traffic noise map, and consequently made excess noise map. Using excess noise map, we assessed areas which exceed environmental noise level standards and noise guidelines quantitatively and effectively through GIS spatial analysis, and consequently more accurate noise exposed area and noise exposed population could be estimated. To show buildings' outer walls noise exposure, we analyzed 3D urban noise distributions using 3D-analysis of GIS.

The Effect of Surface and Vertical Observation Data Assimilation on the Horizontal and Vertical Flow Fields Depending on the Upper Wind Conditions (종관 특성에 따른 지상 및 연직 관측자료 동화가 수평 및 연직 확산장에 미치는 영향)

  • Choi, Hyun-Jung;Lee, Hwa-Woon;Kim, Min-Jung
    • Journal of Korean Society for Atmospheric Environment
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    • v.26 no.2
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    • pp.177-189
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    • 2010
  • In order to incorporate correctly the large or local scale circulation in an atmospheric model, a nudging term is introduced into the equation of motion. The MM5 model was used to assess the meteorological values differences in each case, during ozone episode days in Gwangyang bay. The main objective of this study is to investigate the effect of horizontal and vertical flow fields according to the surface and vertical observation data assimilation by upper wind conditions. Therefore, we carried out several numerical experiments with various parameterization methods for nudging coefficient considering the upper wind conditions (synoptic or asynoptic condition). Nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, therefore appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. Obviously, under the weak synoptic wind, there was apparent advantage associated with nudging coefficient by the regional difference. The accuracy for the prediction of the meteorological values has been improved by applying the appropriate PBL (Planetary Boundary Layer) limitation of circulation.

Characteristics of the Extratropical Transition of Tropical Cyclones over the Western North Pacific using the Cyclone Phase Space (CPS) Diagram (북서태평양에서 저기압 위상 공간도법을 이용한 태풍의 온대저기압화 특성 분석)

  • Lee, Ji-Yun;Park, Jong-Suk;Kang, KiRyong;Chung, Kwan-Young
    • Atmosphere
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    • v.18 no.3
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    • pp.159-169
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    • 2008
  • The characteristics of the typhoon's extratropical transition (ET) over the western North Pacific area were investigated using the cyclone phase space (CPS) diagram method suggested by Hart (2003). The data used in this study were the global data assimilation prediction system (GDAPS) and NCEP data set. The number of typhoons selected were 75 cases during 2002 to 2007, and the three parameters were analyzed : the motion relative thickness asymmetry of the storm (B), the upper thermal wind shear and the lower thermal wind shear. Comparing the best-track data provided by the Regional Specialized Meteorological Center /Tokyo, the time of the ET based on CPS was 2~6 hours earlier than the best-track data. And it was shown that the 400- km and 30 kt wind radius of storm for the CPS method were better agreement than the previous suggested radius 500- km.

Assessment of some parameters of corrosion initiation prediction of reinforced concrete in marine environments

  • Moodi, Faramarz;Ramezanianpour, Aliakbar;Jahangiri, Ehsan
    • Computers and Concrete
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    • v.13 no.1
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    • pp.71-82
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    • 2014
  • Chloride ion ingress is one of the major problems that affect the durability of concrete structures such as bridge decks, concrete pavements, and other structures exposed to harsh saline environments. Therefore, durability based design of concrete structures in severe condition has gained great significance in recent decades and various mathematical models for estimating the service life of rein-forced concrete have been proposed. In spite of comprehensive researches on the corrosion of rein-forced concrete, there are still various controversial concepts in quantitation of durability parameters such as chloride diffusion coefficient and surface chloride content. Effect of environment conditions on the durability of concrete structures is one of the most important issues. Hence, regional investigations are necessary for durability based design and evaluation of the models. Persian Gulf is one of the most aggressive regions of the world because of elevated temperature and humidity as well as high content of chloride ions in seawater. The aim of this study is evaluation of some parameters of durability of RC structures in marine environment from viewpoint of corrosion initiation. For this purpose, some experiments were carried out on the real RC structures and in laboratory. The result showed that various uncertainties in parameters of durability were existed.

Projection and Analysis of Future Temperature and Precipitation using LARS-WG Downscaling Technique - For 8 Meteorological Stations of South Korea - (LARS-WG 상세화 기법을 적용한 미래 기온 및 강수량 전망 및 분석 - 우리나라 8개 기상관측소를 대상으로 -)

  • Shin, Hyung-Jin;Park, Min-Ji;Joh, Hyung-Kyung;Park, Geun-Ae;Kim, Seong-Joon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.4
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    • pp.83-91
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    • 2010
  • Generally, the GCM (General Circulation Model) data by IPCC climate change scenarios are used for future weather prediction. IPCC GCM models predict well for the continental scale, but is not good for the regional scale. This paper tried to generate future temperature and precipitation of 8 scattered meteorological stations in South Korea by using the MIROC3.2 hires GCM data and applying LARS-WG downscaling method. The MIROC3.2 A1B scenario data were adopted because it has the similar pattern comparing with the observed data (1977-2006) among the scenarios. The results showed that both the future precipitation and temperature increased. The 2080s annual temperature increased 3.85.0C. Especially the future temperature increased up to 4.57.8C in winter period (December-February). The future annual precipitation of 2020s, 2050s, and 2080s increased 17.5 %, 27.5 %, and 39.0 % respectively. From the trend analysis for the future projected results, the above middle region of South Korea showed a statistical significance for winter precipitation and south region for summer rainfall.