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        검색결과 29

        21.
        2010.01 KCI 등재 서비스 종료(열람 제한)
        Urban watershed can be found in the visible changes in technology, the most realistic satellite images is to use the data. Satellite image data on the indicators for progress on the nature of the change of land use is consistent and repetitive information, regular observation makes possible the detailed analysis of space-time. These remote sensing techniques and the type of course and, by using the time series history, the past, the dynamic model and the randomized prediction methodology for the conversion process if the city and river basin cooperation of the space changes effectively will be able to extrapolate. For each of the main changes in river flow, depending on the area of urbanization as determined according to reproduce the duration of the relationship between the urbanization of the area and runoff can be represented as a linear polynomial expression was, if a linear expression in the two fast slew rate of 0.858 to 0.861 showed up, and fast slew rate of 0.934 to 0.974 for the polynomial are reported. Change of land use changes in the watershed of the flow is one of the most affecting elements. Therefore, changes in land use of the correct classification of rivers is a more accurate calculation of the amount of the floodgate. In particular, using the Landsat images through the image of the land use category, land use past data and calculated using the Markov Chain model and predict the future land use plan in the water control project will be used for large likely.
        22.
        2007.10 KCI 등재 서비스 종료(열람 제한)
        블랙 라스베리 과실의 성숙정도에 따른 항산화 활성과 이와 관련된 인자인 총페놀성 함량 및 비타민 C 함량의 변화를 측정하였다. 이러한 결과들로부터 과실의 성숙 단계에 따른 활성 및 성분변화 그리고 이들 간의 상관관계를 구명하였다. 블랙 라스베리 과실의 항산화활성측정 결과, 자유 라디칼 소거능 및 환원력 모두 과실이 성숙함에 따라 감소하였다. 또한 항산화 활성과 밀접한 관계가 있는 총페놀 함량 및 비타민 함량 역시 과실이 성숙함에 따라 감소하였다. 자유 라디칼 소거능은 과실 결실 5일 후에서 125ppm 농도에서 61.67%로 최대치를 나타내었으며 환원력은 과실 결실 10일 후가 0.71로 최대였다. 총페놀 함량과 비타민 C함량의 최대치는 각각 220.73ug/g과 540.45ug/g였다. 여러 인자들에 의한 상관관계 분석 결과 자유 라디칼 소거 활성과 환원력 그리고 환원력과 총페놀 함량과의 상관관계는 각각 r=0.9861와 r=0.9889로 고도의 상관관계를 나타내었다. 이상의 결과를 종합하여 보면, 블랙 라스베리를 수확함에 있어 완숙과보다는 미숙과가 약리적인 측면에서는 유용한 성숙단계라 할 수 있지만 크기나 무게 그리고 맛이나 과색에서는 완숙단계가 식용으로는 적합하고 항산화 활성 등에서는 낮으나 이용 가능한 약리 효과를 가지고 있다고 할 수 있다.
        23.
        2006.01 KCI 등재 서비스 종료(열람 제한)
        Heat transfer and flow characteristics in a pipe in which the rotating cutting tool for boring a underground pipe without digging were considered in this study. The amount of heat generation due to the friction between the rotating cutter and pipe wall, mixing flow of air and water injected to cool down are the two important factors to design the boring machine. Computational fluid dynamics analysis using the Eulerian mixture model and the standard k-ε turbulence model was used to analyze the complex phenomena in a pipe during the process. Results show that pipe wall temperature decreased with increasing the cooling water inlet velocity. It is also shown that pipe wall temperature was lowered when the cutter rotation speed was increased until 600 rpm. There was no further cooling effect over 600 rpm.
        25.
        2000.02 KCI 등재 서비스 종료(열람 제한)
        As the tideland reclamation is done on a large scale these days, construction work is active in the coastal areas. Facilities in the coastal areas must be built with the tide characteristics taken into consideration. Thus the tide characteristics affect the overall reclamation plan. The analysis of the tide data boils down to a harmonic analysis of the hourly changes of long-term tide data and extraction of unharmonic coefficients from the results. Since considerable amount of tide data for the West Coast are available, the existing data can be collected and can be used to obtain the temporal changes of the tide by being fitted into the tide prediction model. The goal of this thesis lies in assessing whether the mean sea level used in the field agrees with the analysis results from the long-term observation data obtained with their homogeneity guaranteed. To achieve this goal, the research was conducted as follows. First the present conditions of the observation stations, the land level standard, and the sea level standard were surveyed to derive a vertical standard. Then the causes for the changes in the mean sea level were analyzed to set up a time series model formula for representing them. To secure the homogeneity of the time series, each component was separated. Lastly the mean sea level used in the field was assessed based on the results obtained from the analysis of the time series.
        26.
        2000.02 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study is to estimate the low-flow statistics at the mountainous watershed. The formulation for the estimation of the design low-flow statistics was obtained by means of a hydraulic approach applied to a simple conceptual model for a mountainous watershed. Three of the independent variables associated with the low-flow statistics is watershed area(A), average basin slope(S) and the base flow recession constant(K); Watershed area was measured from topographic maps and average basin slope is approximated in this study using Strahler's slope determining method. And base flow recession constant computed using Vogel and Kroll's method. Unfortunately, this method is usually unavailable at ungaged sites. In this study, recession constant at ungaged sites is estimated using graphical regression method used by Giese and Mason. The model for estimating low-flow statistics were applied to all 61 catchments in the Sumjin, Mankyung basin.
        27.
        1997.06 KCI 등재 서비스 종료(열람 제한)
        For the prediction of multi-site rainfall with radar data and ground meteorological data, a rainfall prediction model was proposed, which uses the neural network theory, a kind of artifical intelligence technique. The input layer of the prediction model was constructed with current ground meteorological data, their variation, moving vectors of rainfall field and digital terrain of the measuring site, and the output layer was constructed with the predicted rainfall up to 3 hours. In the application of the prediction model to the Pyungchang river basin, the learning results of neural network prediction model showed more improved results than the parameter estimation results of an existing physically based model. And the proposed model comparisonally well predicted the time distribution of rainfall.
        28.
        1995.06 KCI 등재 서비스 종료(열람 제한)
        Generally, It is introduced to well-known other models without considering tidal current of the field. The paper presents field measurements and numerical model solving velocity field of Cheonsu Bay by two-dimensional tidal model. It was proved that this scheme is easy to handle complex topography. Computed results is represented characteristics of tidal current for Cheonsu Bay. The results of the study can be summarized as follows ; 1. Tide form number has 0.21 value. Tidal range estimated 630.3 ㎝ on spring, 454.1 ㎝ on mean and 277.9 ㎝ on neap, respectively. 2. Tidal current has semi-diurnal form. Distance of traveling observed 16.6 ㎞ on flood and 15.5 ㎞ on ebb. 3. Tidal velocity showed reversing current. It was found that tidal velocity above 100 ㎝/sec is about 20 %. 4. Computed results are in good agreement with the observed data. Applying the algorithm to Cheonssu Bay, velocity fields and dry bank phenomena are simulated well in spite of complex topography. 5. An advanced study on the effects of open boundary conditions should be continuously performed.
        29.
        1995.06 KCI 등재 서비스 종료(열람 제한)
        This paper presents effective simulation of the dispersion of thermal discharge which can be relesed at Boryong power plant. Applied numerical models are finite difference method for hydrodynamic analysis and Masch-model comprised of conditions for ambient current velocity. Application of these models is done in Cheonsu Bay. Summing up the results of this study are as follows; 1. It is found that the result for measurement of temperature appears high at southwardly Songdo on flood. The reason is that tidal currents which flowed north direction were accompanied with southwardly dispersed thermal discharge. A minute particle of thermal plume has a tendency to dispers inward Deacheon Bay. 2. According to the results of numerical experiment, maximum distance for thermal discharge dispersion appeared 10.8㎞ at lower part and 8.6㎞ at upper part with power plant outlet as starting point. 3. Comparative the numerical simulation and Airbone Multispectral Scanner indicated that thermal discharge should be verified separative phenomena. The simulated results were compared with field data set showing good agreement. It is concluded that these model can be simulated well.
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