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        검색결과 73

        61.
        2007.01 KCI 등재 서비스 종료(열람 제한)
        본 연구의 목적은 결측 혹은 미계측 증발접시 증발량과 우리나라에서 계측되고 있지 않은 알팔파 기준증발산량의 산정을 위하여 유전자 알고리즘이 내재된 일반화된 회귀신경망모형을 개발하고 적용하는데 있다. 우리나라에서는 장기간동안 증발산계를 이용하여 알팔파 기준증발산량의 관측이 시행되지 않고 있으므로, 본 연구에서는 Penman-Monteith(PM) 공식을 이용하여 산정된 값을 계측된 알팔파 기준증발산량으로 가정하였다. 본 연구를 통하여 최적 증발접시 증발량
        63.
        2003.04 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 낙동강 상류유역의 병렬 다목적댐군인 안동 및 임하다목적 댐의 장기간 유입량을 산정하는데 공간추계 신경망모형이 사용되었다. 공간추계 신경망모형은 역전파 알고리즘으로 LMBP와 BFGS-QNBP를 각각 사용하였다. 공간추계 신경망모형의 구조는 입력층, 은닉층 및 출력층의 3개의 층과 차례대로 8-8-2개의 노드로 구성되어 있다. 입력층 노드는 안동 및 임하다목적 댐의 월평균유입량, 월면적강우량, 월별 증발접시 증발량과 월평균기온으로 구성되어
        64.
        2001.08 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 중소하천수계에서 수문학적 예측을 위하여 Hybrid Neural Networks의 일종인 반경기초함수(RBF) 신경망모형이 적용되었다. RBF 신경망모형은 4종류의 매개변수로 구성되어 있으며, 지율 및 지도훈련과정으로 이루어져있다. 반경기초함수로서 가우스핵함수(GKF)가 이용되었으며, GKF의 매개변수인 중심과 폭은 K-Means 군집알고리즘에 의해 최적화 된다. 그리고 RBF 신경망모형의 매개변수인 중심, 폭, 연결강도와 편차벡터는 훈련
        65.
        2001.06 KCI 등재 서비스 종료(열람 제한)
        논토양의 토성에 따른 벼의 수량, 관개용수량 및 지하삼투수량의 차이를 구명코자 사양토, 식양토, 식토 등 3종류의 토성에서 1999년과 2000년 라이시미터(lysimeter) 조건에서 실험한 결과는 다음과 같다. 1. 벼의 초장과 분얼 및 쌀 수량은 토성 처리간 유의한 차이가 없었다. 2. 벼 생육기간 중 총관개용수량은 1년차에는 식양토, 사양토, 식토 순으로 각각 3,306, 2,650, 2,002 l/m2 이었고 2년차에는 사양토, 식양토, 식토 순으로 각각 5,281, 4,984, 3,968 l/m2 이었다. 3.벼 재배기간 중 총지하삼투수량은 1년차에는 식양토, 사양토, 식토가 각각 2,141, 1,228, 862 l/m2 이었고, 2년차에는 사양토, 식양토, 식토에서 각각 4,448, 3,833, 2,925 l/m2 이었다. 4. 지표면하 10cm까지의 깊이에 분포하는 벼 뿌리의 비율은 사양토 56.0%, 식양토 61.4%, 식토 72.0%로 식토일수록 표층부 분포 비율이 높았다. 5. 논토양에서 지하삼투수량은 토성의 영향도 있으나 토양 중 벼 뿌리 생장량의 영향도 있어서, 뿌리 생장량이 많았던 처리구의 지하삼투수량이 증가하는 것으로 나타났다.
        66.
        2000.10 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 낙동강 진동지점에서 일유출량을 예측하기 위하여 신경망모형이 제시되었다. 신경망모형의 구조는 CASE 1(5-5-1)과 CASE 2(5-5-5-1)로 구성하였으며, 은닉층의 수에 따라 두 가지의 모형으로 분류하였다. 각 신경망모형은 광역최소점과 훈련임계치에 수렴하는데 기존의 역전파훈련 알고리즘(BP) 보다 뛰어난 Fletcher-Reeves 공액구배 역전파훈련 알고리즘(FR-CGBP)과 축적된 공액구배 역전파훈련 알고리즘(SCGBP)을 이용
        67.
        2000.04 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 낙동강유역의 주요 수위표지점중 진동수위표지점에서 홍수위를 예측하기위한 신경망모형인 WSANN모형이 제시되었다. WSANN모형은 모멘트방법, 초기조건의 개선 및 적응학습속도에 의해 보완되어진 개선된 역전파훈련 알고리즘을 이용하였고, 본 연구에 사용된 자료는 훈련자료와 테스팅자료로 분할하였으며, 최적 은닉층 노드수를 결정하기 위하여 은닉층노드와 임계학습횟수로부터 경험식이 유도되었다. 그리고 WSANN모형의 보정은 4개의 훈련자료에 의해 실시되
        68.
        2000.02 KCI 등재 서비스 종료(열람 제한)
        In this study, the movable bed model testing was carried out so as to analyze bed profile changes including predicting scouring and deposition of bed profile and to solve hydraulic problems affecting with bed and both-bank between upstream and downstream of intake weir in the Nakdong river channel. The movable bed model testing consists of fundamental test, movable model test and numerical analysis method respectively. The fundamental test was enforced to analyze relationship of discharge and sediment load in the tilting flume. When the movable model test was worked, it was shown that sediment budget between input sediment load and output sediment load was balanced exactly. As a result of movable model test, it was presented that scouring and deposition changes in quantities between the upstream and downstream of modification weir were less than those of nature and planning weir. Finally, numerical analysis method was operated by 1-dimensional bed profile changes model ; HEC-6 model so as to complement unsolving hard problems during movable model test. So, modification weir will be sustained the stable bed profile changes than any other weirs in the study channel.
        69.
        1999.08 KCI 등재 서비스 종료(열람 제한)
        In this study, the regional frequency analysis is used to determine each subbasin drought frequency with reliable monthly precipitation and the L-Moments method which is almost unbiased and has very nearly a normal distribution is used for the parameter estimation of monthly precipitation time series in Nakdong river basin. As the result of this study, the duration of '93-'94 is most severe drought year than any other water year and the drought frequency is established as compared the regional frequency analysis result of cumulative precipitation of 12th duration months in each subbasin with that of 12th duration months in the major drought duration. The Linear regression equation is induced according to linear regression analysis of drought frequency between Nakdong total basin and each subbasin of the same drought duration. Therefore, as the foundation of this study, it can be applied proposed method and procedure of this study to the water budget analysis considering safety standards for the design of impounding facilities large-scale river basin and for this purpose, above all, it is considered that expansion of reliable preciptation data is needed in watershed rainfall station.
        71.
        1998.12 KCI 등재 서비스 종료(열람 제한)
        In this study, the Dilution Method is used to measure river discharge through the hydraulic model test. the dilution method is divided into Constant-Rate-Injection Method and Slug-Injection Method in the river discharge measurement techniques. When the dilution method is applied in the hydraulic model flume, it is analyzied that the estimated error of constant-rate-injection method is less than that of the slug-injection method, and the result shows that floodflow analysis is more efficient than lowflow analysis as compared observed discharge with calculated discharge. The result of statistical error analysis shows that the constant-rate-injection method is appropriate technique for the measurement of the river discharge. Therefore, the dilution method among the river discharge measurement techniques can be applied for the river basin which can`t be measured with current meter or unsteady-flow regime in the urban-small drainage or hydraulic structure equipment area and can be obtained more exact results than any other discharge measurement techniques.
        72.
        1998.10 KCI 등재 서비스 종료(열람 제한)
        This study is aimed at the development of the adequate sediment yield formulas in Wi-Stream basin ; IHP representative basin in Korea. As a result of applying outstanding sediment yield formulas among the existing formulas. It is analyzed that including the Engelund & Hansen formula, Yang formula is proper to the Wi-Stream basin. And as a result of sensitivity analysis to the sediment parameters it is analyzed that Rijn and Ackers & White formula is more sensible than any other formulas which has been applied the velocity and depth among the parameters. Also, Engelund & Hansen and Yang formula is less sensible than any other formulas. In Wi-Stream basin, it is analyzed that Yang and Engelund & Hansen formula is the most suitable sediment yield formula in this study. But because the existing formulas had been developed in foreign countries and applied the foreign natural rivers and reservoirs, it makes careful use of Korean alluvial river and hoped that it will be developed the most adequate formula in Wi-Stream basin.
        73.
        1998.08 KCI 등재 서비스 종료(열람 제한)
        The objectives of this study is to evaluate the total runoff yield, peak flow and peak flow travel time depending on the urbanization, return period and rainfall patterns at the downstream of Manchon urban watershed in TaeGu City. SWMM(Storm Water Management Model) is used for runoff analysis based on 5 different steps of urbanization and 4 different types of Huff`s quartile according to 8 return periods. It is analyzed that the order of total runoff yield according to rainfall patterns is Huff`s 4, Huff`s 2. Huff`s 3 and Huff`s 1 quartile, that of peak flow magnitude is Huff`s 2, Huff`s 1, Huffs`4 and Huff`s 3 quartile at present development ratio. under the 60, 70, 80 and 90% of urbanization to the 50% of urbanization by means of the rainfall patterns, the mean increasing ratio of total runoff yield for each case is 4.55, 11.43, 16.07 and 20.02%, that of peak flow is 5.82, 13.61, 17.15 and 18.83%, the mean decreasing ratio of peak flow travel time is 0.00, 2.44, 5.07, and 6.26%, the mean increasing ratio of runoff depth is 4.51, 11.42, 16.02 and 20.05%, respectively. the mean increasing ratio of total runoff yield by means of each return period & Huff`s 3 quartile is 4.86, 12.11, 17.14 and 21.56%, that of peak flow is 5.89, 13.97, 17.82 and 19.71%. Therefore, as the result of this study, it can be used for principal data as to storm sewage treatment and flood damage protection planning in urban small watershed.
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