• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.477-480
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• 2008

최근 지구 온난화에 따른 이상기후 변화로 인해 게릴라성 집중호우와 같은 다양한 강우패턴이 발생되고 있으며 홍수기 저수지 유입량은 비록 동일 양의 강우가 발생한 경우라도 선행강우량, 무강우일수, 호우발생전 초기유입량 등과 같은 수문사상들로 인해 많은 차이가 발생되고 있는 실정이다. 따라서 본 연구에서는 신속함이 요하는 홍수기 저수지 운영시 신속한 의사결정을 돕기 위해 과거 홍수기댐 유입율과 유역 수문사상과의 관계를 분석하고자 한다. 이를 위해 한강수계내 다목적 댐인 소양강, 충주 및 횡성댐의 과거 호우사상을 대상으로 유역내 각종 수문사상들을 독립변수로 한 회귀분석을 실시하여 홍수 이벤트 발생전 유역상황을 토대로 예상되는 강우에 따른 예상 유출율을 산정한다. 과거 호우사상에 대한 유출율 산정은 직접유출과 기저유출을 분리한 후 직접유출이 종료되는 시점까지의 유출량과 강우량의 비로서 산정하였으며 직접유출과 기저유출 분리방법은 주파수 분리방법을 이용하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.5B
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• pp.572-581
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• 2001

본 논문에서는 위성통신에서 강우감쇠에 따라 가변 부호화율을 적용시킬 수 있는 적응형 부호화 기법에 대한 연구를 하였다. 따라서, 3bit 연판정을 적용한 Viterbi 복호기를 이용하여 QPSK와 TC-8PSK 신호를 복호할 수 있는 pragmatic TCM과 LSB 부호화 알고리즘에 대해 여러 부호화율에서 성능분석을 하였다. 또한 구현을 위한 최적의 파라미터를 설정하여 부호화율 2/3를 가지는 pragmatic TCM을 VHDL 모델링 하였다. 구현결과 PLEX10KE100EQC208-1 CPLD 칩으로 구현 가능하였으며, 42.36 Mbps의 복호 속도를 가진다. 실제 ASIC 설계시 CPLD 속도보다 약 5∼6배의 고속화가 가능하므로, 200 MHz 트렌스 폰더를 갖는 Ka 대역 초고속 위성통신 시스템에서 강우 감쇠에 대처하기 위한 적응형 트렐리스 부호화방식에 적용할 수 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.280-280
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• 2021

대청댐은 1980년에 준공하여 금년도 현재 40년이 경과한 댐이다. 40년간의 수문자료를 확보하고 있으나, 준공이후 94년까지는 홍수기 시간자료가 축적이 안 되어 분석이 불가한 상황이며, '95년부터 2020년까지는 홍수기 시간자료를 최대한 활용하여 홍수수문분석을 시행하였다. 홍수의 기초자료인 강우량을 발생원인(태풍, 장마, 집중호우, 전선형강우)별로 구분하였으며, 강우의 시간분포(증가, 감소, 증가감소, 균일, 감소증가, 증가계단, 감소계단, Huff1, Huff2, Huff3, Huff4)의 11가지로 모든 호우사상에 대하여 구분을 하였으며, 적용모형인 저류함수법의 주요 매개변수(K, P, T_l, F₁, R_sa)는 최적화 기법(Golden Search)을 이용하여 산정하였다. 또한, 유입량과 방류량 관계에 의한 홍수조절율, 주요호우 사상의 이전 상황인 무강우일수, 선행 강우를 분석하여 유출율에 미치는 영향을 파악하고자 하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1027-1035
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• 2013

In this study, two rainfall patterns are utilized for practical consideration of rainfall phenomena in unsaturated soil slope design. One is the I.D.F (Intensity-Duration-Frequency) method which is an existing design rainfall method and ignores the effect of the variation of the rainfall according to the time. The other is the Huff method which considers this effect oppositely. First, the safety of factor of the slope according to the variation of an initial suction which means the precedent rainfall effect was examined by means of the application of the I.D.F method. Through the application of two rainfall patterns, it was discussed how the rainfall pattern affects the factor of safety of the slope. As a result, it is found that the Huff method is more practical on the evaluation of the slope stability than the I.D.F method.

• The Journal of Engineering Geology
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• v.20 no.1
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• pp.61-70
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• 2010

In case of groundwater recharge estimation using water table fluctuation method, specific yield affects the accuracy and confidence level of recharge rate. Nevertheless, there have been few studies on the method for the accurate estimation of specific yield in Korea. Specific yield estimated from the relationship between rainfall and groundwater levels is reasonable compared to the other methods. However, lots of factors such as artificial pumping, evapotranspiration by the plants, and a sudden increase in water levels by a heavy rainfall can affect the pattern of groundwater levels' fluctuation and make an over-estimated or under-estimated specific yield. This study obtained a reasonable specific yield by using a daily or 12 hourly average of rainfall and groundwater levels measured in a dry season.

• Journal of Satellite, Information and Communications
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• v.11 no.3
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• pp.110-113
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• 2016

In this paper of ka band satellite communication using geostationary satellite is very weak to rainfall. So the rain attenuation reflect the values calculated using the satellite communication links vulnerable when designing a more reliable rainfall area distribution of rain attenuation and accurate predictive models must analyze the link budget. In this paper, by utilizing domestic distribution analysis in the recent local rainfall Crane and regional rainfall in the model and compared with the country of the regional distribution of rainfall in your area to fit the rain attenuation in Ka band frequency characteristics Crane rain attenuation prediction models were analyzed to between geostationary satellites and ground station position, distance and year time percentage(%).

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1989.05a
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• pp.1-2
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• 1989

• Journal of the Korean Geotechnical Society
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• v.30 no.10
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• pp.45-54
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• 2014

Many studies have been made on investigation, design, explanation and treatments etc. to minimize slope failure. However, the problem is that failures of cutting slope and natural slope due to Typhoon and localized heavy rainfall are still not reduced. It is difficult to treat the problem by only strengthening the design standard. And it is very necessary to carry out design and safety analysis under the most suitable conditions considering foundation and rainfall characteristics. In this study, variations of safety factor were discussed from different aspects to investigate the influence of different parameters of rainfall and analysis conditions. Rainfall and foundation conditions are supposed to be the most sensitive parameters to slope stability, and numerical analysis were performed by changing parameters of the two conditions. Rainfall behavior is based on the domestic statistical rainfall and foundation condition is selected as unsaturated soils. Study results show that, application of rainfall characteristics in different area and parameters of unsaturated soils are responding sensitively to variations of slope safety. Therefore, the input parameters should be fully examined when performing the practical design.

• The Journal of Engineering Geology
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• v.21 no.1
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• pp.25-34
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• 2011

We applied a slope-stability analysis method, considering infiltration by rainfall, to the construction site where an express highway is being extended. Slope stability analysis that considers infiltration by rainfall can be classified into three methods: a method that considers the downward velocity of the wetting front, a method that considers the upward velocity of the groundwater level, and a method that considers both of these factors. The results of slope stability analysis using $Bishop^{\circ}{\Phi}s$ simplified method indicate that the safety factor due to the downward velocity of the wetting front decreases more rapidly than that due to the upward velocity of the groundwater level. For the third of the above methods, the safety factor decreases more rapidly than for the other two methods. Therefore, slope stability during rainfall should be analyzed with consideration of both the downward velocity of the wetting front and the upward velocity of the groundwater level.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3C
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• pp.167-178
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• 2008

Rainfall-induced slope failures were simulated by seepage and stability analyses for actual slopes of weathered soils. After undisturbed sampling and testing on a specimen of unsaturated conditions, a seepage analysis was performed under actual rainfall and it was found that the pore water pressure increased at the boundary of soil and rock layers. The safety factor of slope stability decreased below 1.0 and the failure of actual slope could be simulated. Under design rainfall intensity, the seepage analysis could not include the effects of the antecedent rainfall and the rainfall duration. Due to these limitations, the safety factor of slope stability resulted in above 1.0, since the hydraulic head of soil layers had not be affected significantly. In the analysis of another slope failure, the parameters of unsaturated conditions were evaluated using artificial neural network (ANN). In the analysis of seepage, the boundary of soil and rock was saturated sufficiently and then the safety factor could be calculated below 1.0. It was found that the failure of actual slope can be simulated by ANN-based estimation.