• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.941-941
• /
• 2012

최근 이상기후로 인한 강우량 증가와 집중호우가 빈번히 발생하고 있는 추세이다. 작년 서울지역의 하루 강우량은 301.5mm, 1시간 최대 강우량이 113mm를 기록하였고, 침수와 산사태 인한 인적, 물적 피해가 나타나면서 재해위험이 크고 예측한계를 벗어난 특이기상 발생빈도가 증가했다. 강수일수 또한 1980년대 36일에서 2011년 48일로 빠르게 증가하고 있다. 본 연구에서는 특이기상 발생 원인을 강우량으로 고정하여 확률강우량 증가에 따라 홍수량의 변화양상을 해석하였다. 변화한 홍수량이 홍수위에 미치는 변화양상을 분석하기 위해 금강수계의 무심천유역에 위치한 청주강우관측소를 선정하였고, 대상유역의 확률강우량을 증가시켜 빈도해석을 통한 각각의 재현기간에 발생한 면적확률강우량을 산정하였다. 또한 GIS 프로그램을 이용해 지형인자를 추출하고 추출된 지형인자를 이용하여 매개변수를 산정하였다. HEC-HMS 모형의 계산조건에서 손실우량은 SCS CN, 유출변환은 Clark 단위도법을 적용하였다. 그리고 HEC-RAS 모형에서는 자연하천에 주로 적용하는 부등류 모델링을 수행하여 결과값의 조건별 양상을 분석하였다. 분석결과 확률강우량 증가율에 대한 홍수량은 비슷한 변화율을 보여주었고, 홍수량 증가에 대한 홍수위 변화율은 동일한 비율만큼 반영되지 않음을 판단할 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2015.05a
• /
• pp.63-63
• /
• 2015

산사태나 토석류와 같은 산지재해가 빈발하고 인명과 재산의 피해가 증가함에 따라 적절한 대책이 시급하게 요구되고 있다. 토석류 매커니즘에 대한 많은 선행 연구가 이루어졌으며, 토석류 수치해석은 설정된 지형이나 수문곡선 등의 조건하에서 토석류의 발생, 이동, 퇴적, 범람범위 등의 거동을 표현하는 것이다. 본 연구에서는 토석류 해석에 자주 이용되는 Takahashi model과 Egashira model을 이용하여 침식과 퇴적과정을 모의하였다. Takahashi model에서는 토석류, 소류 상집합유동 등에 따라 유동형태가 달라지는 반면, Egashira model에서는 유동형태의 구분없이 침식이나 퇴적이 일어나지 않는 평형경사를 상정하여 하상구배가 평형구배를 만족시키는 방향으로 침식/퇴적이 발생한다고 평가한다. 이러한 각각의 토석류 모델을 이용하여 여러 가지 하상에서의 침식현상, 퇴적현상을 수치모의하고 각 모델의 해석결과를 비교하였다. 또한 이동상에서의 침식/퇴적거동을 해석하였으며, 실제 지형에 대한 적용가능성을 검토하였다. 이러한 토석류 수치해석 결과를 이용하여 토석류재해의 규모나 범위를 예측할 수 있으며 실제로 발생한 토석류재해의 검증, 사방구조물의 기능평가에도 유용하게 이용될 수 있다. 본 연구에서는 1차원해석에 머물러 있으나 계류상의 거동을 표현하고 사방구조물의 위치선정을 위해서는 무리가 없으며, 향후 2차원해석을 통해 범람거동을 해석한다면 토석류위험지도 작성에 유효할 것으로 판단되었다.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.21 no.3
• /
• pp.48-62
• /
• 2018

In this study, landslide of debris flow occurred at 51 sites around Daeryounsan located in between Chuncheon-si and Hongcheon-gun during July in 2013 were investigated in field and behavior characteristics of debris flow were analyzed on the basis of records of rainfall and site investigation. According to debris flow types of channelized and hill slope, location and slope angle of initiation and deposit zone, and width and depth of erosion were investigated along entire runout of debris flow. DEM(Digital Elevation Model) of Daeryounsan was constructed with digital map of 1:5,000 scale. Land slide hazard was estimated using SINMAP(Stability INdex MAPping) and the predicted results were compared with field sites where debris flow occurred. As analyzed results, for hill slope type of debris flow, predicted sites were quite comparable to actual sites. On the other hand, for channelized type of debris flow, debris flow occurrence sites were predicted by using stability index associated with topographic wetness index. As analyzed results of 4 different conditions with the parameter T/R, Hydraulic transmissivity/Effective recharge rate, proposed by NRCS (Natual Resources Conservation Service), predicted results showed more or less different actual sites and the degree of hazard tended to increase with decrease of T/R value.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.35 no.5
• /
• pp.1073-1082
• /
• 2015

The behavior of the unsaturated soil slope can be influenced by the various factors such as the hydraulic characteristics, the mechanical characteristics, the coefficient of conductivity, the stratifications, the rainfall conditions i.e. the rainfall intensity, the rainfall pattern, the duration time of the rainfall and the antecedent rainfall etc. It is known that the slope failure is influenced greatly by the antecedent rainfall rather than the rainfall condition at the failure time, so the antecedent rainfall is supposed to be a very important factor in slope stability analysis among these factors. To predict and to prevent the slope failure by the rainfall, the distribution of the matric suction by the antecedent rainfall must be considered first of all and the slope stability analysis should be carried out by considering the successive rainfall characteristics. In this research, 3 samples with different quantity (5%, 10%, 20%) of silts were prepared and the SWCC (Soil-water characteristic curve) tests were carried out and the associated parameters were analyzed. After analyzing the distribution of the matric suction and the change of the mechanical characteristics such as the stress and the strength when applying the antecedent rainfall for one month and the successive intensive rainfall for 12 hours, the slope stability analyses were carried out numerically. And the influence of the antecedent rainfall for one month and the SWCC on the stability of a slope were compared and analyzed.

• Geophysics and Geophysical Exploration
• /
• v.10 no.3
• /
• pp.203-210
• /
• 2007

As a part of basic studies on monitoring of landslides and slope stability using SP measurements, micro-electric potentials of rock samples were measured accompanied with the rock failure by a uniaxial loading test were measured. The measurement system consists of a 8 channel A/D converter with 24 bit resolution, uniaxial loading tester, strain gages and 4 sets of electrode attached to a rock sample. Rock samples of granite, limestone, and sandstone were tested. Also, mortar samples were tested in order to monitor electric-potentials of a uniform sample. Micro-electric potentials were detected in all saturated samples and the strength of them increased as the loading force increased. Sandstone samples showed the largest strength of micro-electric potential and it followed limestone and granite samples, which indicates a positive relationship with porosity of rocks. The mechanism generating these micro-electric potential can be explained in terms of electro-kinetics. In case of dry samples, micro-electric potential could be observed only in sandstone samples, where piezoelectric effect played main role due to high contents of quartz in sandstone samples. We found that biggest micro-electric potentials were observed at the electrodes near the crack surface of rock samples. This is very encouraging result that SP monitoring can be applied to predicting landsliding or to estimate collapsing position combining with monitoring of acoustic emissions.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.12 no.3
• /
• pp.64-129
• /
• 1992

최근 초지중심 사양형태의 증가와 초지면적의 확대에 따라 단순한 사료로서가 아니라 영양가치가 높고 기호성이 높은 목초생산이 요구되고 있다. 그러나, 고위생산을 위해 다량으로 사용된 질소질비료에 의하여 질산태 중독 등의 문제가 야기되고 있어 목초의 생리 및 영양에 관한 연구가 필요하게 되었다. 사료성분 혹은 영양가치에 대한 연구는 이미 일찍부터 다루어져 왔으나, 주로 야초류, 청예작물 및 농가부산물 등의 일반성분 특히, 조단백질과 조섬유함량의 연구가 주가 되었고 다년생 목초류에 대한 연구는 1975년경부터 본격화 되기 시작하였다. 그동안 한국초지학회지와 축산학회지($1972\sim1991$)에 게재된 총 151편의 생리 및 영양에 관한 연구 중에서 다년생 목초류를 취급한 것은 불과 63편에 머물고 있다. 이 분야의 연구는 각종 목초 사료작물에 대한 재배조건과 생육단계에 따른 생리생태학적 연구와 사료성분, 소화율 및 가소화양분 함량의 일반적인 변화, 경향을 검토하여 사료 가치 평가를 위한 기준으로 삼았다. 그러나 다년생 목초류는 물론 사료 작물에 있어서 육종 생리분야의 연구는 매우 미흡한 상태로써 단지 발아, 생육, 저장탄수화물 및 유독성분 등 단편적인 연구만이 행해지고 있을 뿐이다. 또한 사료 성분이 가축의 기호성에 미치는 영향을 구명하기 위한 연구는 거의 이루어지고 있지 않으므로 금후 탄수화물과 미량 요소에 대한 자세한 연구 검토가 필요하다고 생각된다. 특히 목초와 사료작물의 화학적인 조성과 가축의 생리에 관련한 여러가지 문제들도 앞으로 보다 깊이 연구되어야 할 과제라고 생각된다.권을 잡기 위해 10년지기였던 IBM과 MS사는 각각 OS/2와 윈도즈를 내세우고 양보할 수 없는 힘겨루기에 들어갔다. 또 이들 양사는 펜컴퓨터,멀티미디어등 차세대제품의 운영체제 시장을 둘러싸고 일찍부터 격전에 들어갔으며 IBM과 MS사의 혼전을 틈타 썬마이크로시스템을 필두로한 워크스테이션 업체 및 유닉스진영까지 고성능 PC시장을 겨냥한 OS를 속속 개발, 90년대의 OS 전쟁은 한치 앞을 내다볼 수 없는 안개국면으로 접어들고 있다. DOS에서 32비트시대,펜컴퓨터, 멀티미디어에 이르는 차세대제품을 둘러싼 업계의 OS 쟁탈전을 통해 OS의 발전동향과 미래를 전망해 본다. results in the large change of the objective function, the sum of squares of deviations of the observed and computed groundwater levels. 본 논문에서는 가파른 산사면에서 산사태의 발생을 예측하기 위한 수문학적 인 지하수 흐름 모델을 개발하였다. 이 모델은 물리적인 개념에 기본하였으며, Lumped-parameter를 이용하였다. 개발된 지하수 흐름 모델은 두 모델을 조합하여 구성되어 있으며, 비포화대 흐름을 위해서는 수정된 abcd 모델을, 포화대 흐름에 대해서는 시간 지체 효과를 고려할 수 있는 선형 저수지 모델을 이용하였다. 지하수 흐름 모델은 토층의 두께, 산사면의 경사각, 포화투수계수, 잠재 증발산 량과 같은 불확실한 상수들과 a, b, c, 그리고 K와 같은 자유모델변수들을 가진다. 자유모델변수들은 유입-유출 자료들로부터 평가할 수

• Journal of the Korean Association of Geographic Information Studies
• /
• v.17 no.4
• /
• pp.101-111
• /
• 2014

Spatial events are predictable using data mining classification algorithms. Decision trees have been used as one of representative classification algorithms. And they were normally used in the classification tasks that have label class values. However since using rule ranking methods, spatial prediction have been applied in the spatial prediction problems. This paper compared rule ranking methods for the spatial prediction application using a decision tree. For the comparison experiment, C4.5 decision tree algorithm, and rule ranking methods such as Laplace, M-estimate and m-branch were implemented. As a spatial prediction case study, landslide which is one of representative spatial event occurs in the natural environment was applied. Among the rule ranking methods, in the results of accuracy evaluation, m-branch showed the better accuracy than other methods. However in case of m-brach and M-estimate required additional time-consuming procedure for searching optimal parameter values. Thus according to the application areas, the methods can be selectively used. The spatial prediction using a decision tree can be used not only for spatial predictions, but also for causal analysis in the specific event occurrence location.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.23 no.4
• /
• pp.415-423
• /
• 2021

Recently, an R-based point time series data validation system has been established for the statistical post processing and improvement of the National Center for AgroMeteorology-Land Atmosphere Modeling Package (NCAM-LAMP) medium-range prediction data. The time series verification system was used to compare the NCAM-LAMP with the AWS observations and GDAPS medium-range prediction model data operated by Korea Meteorological Administration. For this comparison, the model latitude and longitude data closest to the observation station were extracted and a total of nine points were selected. For each point, the characteristics of the model prediction error were obtained by comparing the daily average of the previous prediction data of air temperature, wind speed, and hourly precipitation, and then we tried to improve the next prediction data using Support Vector Machine( SVM) method. For three months from August to October 2017, the SVM method was used to calibrate the predicted time series data for each run. It was found that The SVM-based correction was promising and encouraging for wind speed and precipitation variables than for temperature variable. The correction effect was small in August but considerably increased in September and October. These results indicate that the SVM method can contribute to mitigate the gradual degradation of medium-range predictability as the model boundary data flows into the model interior.

• Journal of the Korean GEO-environmental Society
• /
• v.19 no.9
• /
• pp.29-36
• /
• 2018

Several studies have been conducted on monitoring system and automatic measuring instruments to prevent slope failure in advance in Korea and overseas. However, these studies have quite complex structure. Since most of the measurement systems are installed on the slope surface, the researches are carried on the measurement system that detects sign of slope collapse in advance and alerts are still unsatisfactory. In this study, slope collapse experiments were carried out to understand the slope failure mechanism according to rainfall conditions. The water content and displacement behavior at the early stage of the slope failure were analyzed through the measurement of the ground displacement and water content. The results of this study can be used by local government as a basic data for the design of slope failure alarm system to evacuate residents in case of slope failure or landslide due to heavy rainfall.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.23 no.6
• /
• pp.533-538
• /
• 2013

The damage caused by Recent frequently occurring locality torrential rains is increasing rapidly. In case of densely populated metropolitan area, casualties and property damage is a serious due to landslides and debris flows and floods. Therefore, the importance of predictions about the torrential is increasing. Precipitation characteristic of the bad weather in Korea is divided into typhoons and torrential rains. This seems to vary depending on the duration and area. Rainfall is difficult to predict because regional precipitation is large volatility and nonlinear. In this paper, Very short-term precipitation forecasting pattern model is implemented using KLAPS data used by Korea Meteorological Administration. we designed very short term precipitation forecasting pattern model using GA-based RBFNNs. the structural and parametric values such as the number of Inputs, polynomial type,number of fcm cluster, and fuzzification coefficient are optimized by GA optimization algorithm.