• 지질공학
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• 제3권3호
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• pp.241-252
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• 1993

미국 위스컨신주 도어 지역의 지하수내에서 납성분이 시기적, 장소적으로 불규칙하게 산출되었다. 본 연구에서, 지하수의 납성분의 오염도를 나타내주는 지시자들(검출빈도, 납성분의 평균, 최고 검출농도)과 지하수의 납 오염에 관계가 있을 가능성이 있는 7개의 독립변수들과의 상관계수가 계산되었다. 이 관계의 통계적 중요성은 t-test에 의하여 90%의 신뢰도에서 이루어졌으며, 이 지역에 산재하는 농약(lead-arsenate)의 처리장소가 지하수내 납성분의 요염 원인임을 통계학적으로 입증하였다. 납성분으 산출농도가 높았던 5개의 가정우물로부터 총 112개의 지하수시료가 채취분석되었다. 납성분은 $0.45{\;}\mu\textrm{m}$의 공극 크기를 지닌 여과지에 걸러진 미립자에서 검출되었으며, 여과액에서는 검출되지 않았다. 이러한 결과는 납성분이 이 지역의 지하수내에서 미립자이 상태로 존재함을 지시한다. 따라서, 이 지역에서 납성분의 불규칙한 산출은 미립자상의 납이 수평과 수직으로 발달된 파쇄대와 같은 유동경로를 따라 이동하면서 나타나는 현상으로 고려된다.

• 한국지반공학회논문집
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• 제18권4호
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• pp.119-126
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• 2002

본 논문에서는 암반사면의 절토시 현장지반 시추조사의 불충분한 자료와 비균질한 지반특성에서 오는 불확실성이 암사면의 파괴확률에 미치는 영향을 알아보기 위하여 신뢰성해석을 실시하였고 이를 확정론적 해석결과와 비교하였다. 해석에 사용된 확률변수는 절리면의 점착력과 마찰각, 암반의 단위중량 이었으며 절리면의 경사각은 확률변수로 적용한 경우와 그렇지 않은 경우로 나누어 해석하였다. 해석 결과 대상 절토사면의 경우 확정론적 해석시 안정하게 나타남에도 신뢰도 해석에서는 연약 지질층의 영향에 의한 높은 불명확성으로 인하여 높은 파괴확률을 갖는 것으로 나타났다. 각 확률변수의 평균값과 분산에 대한 파괴확률의 민감도는 점착력이 가장 큰 것으로 나타났으며 평균값이 미치는 민감도가 분산의 경우보다 크게 나타나 현장 지반물성치들에 대한 평균값의 정확한 산출이 중요한 것으로 나타났다.

• Journal of Ecology and Environment
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• 제34권2호
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• pp.149-156
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• 2011

Phenological variables derived from remote sensing are useful in determining the seasonal cycles of ecosystems in a changing climate. Satellite remote sensing imagery is useful for the spatial continuous monitoring of vegetation phenology across broad regions; however, its applications are substantially constrained by atmospheric disturbances such as clouds, dusts, and aerosols. By way of contrast, a tower-based ground remote sensing approach at the canopy level can provide continuous information on canopy phenology at finer spatial and temporal scales, regardless of atmospheric conditions. In this study, a tower-based ground remote sensing system, called the "Phenological Eyes Network (PEN)", which was installed at the Gwangneung Deciduous KoFlux (GDK) flux tower site in Korea was introduced, and daily phenological progressions at the canopy level were assessed using ratios of red, green, and blue (RGB) spectral reflectances obtained by the PEN system. The PEN system at the GDK site consists of an automatic-capturing digital fisheye camera and a hemi-spherical spectroradiometer, and monitors stand canopy phenology on an hourly basis. RGB data analyses conducted between late March and early December in 2009 revealed that the 2G_RB (i.e., 2G - R - B) index was lower than the G/R (i.e., G divided by R) index during the off-growing season, owing to the effects of surface reflectance, including soil and snow effects. The results of comparisons between the daily PEN-obtained RGB ratios and daily moderate-resolution imaging spectroradiometer (MODIS)-driven vegetation indices demonstrate that ground remote sensing data, including the PEN data, can help to improve cloud-contaminated satellite remote sensing imagery.

• Journal of Biosystems Engineering
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• 제36권4호
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• pp.279-284
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• 2011

Protected vegetable production area is greater than 26% of the total vegetable production area in Korea, and portion of protected production area is increasing for flowers and fruits. To secure stable productivity and profitability, continuous and intensive monitoring and control of protected crop production environment is critical, which is labor- and time-consuming. Failure to maintain proper environmental conditions (e.g., light, temperature, humidity) leads to significant damage to crop growth and quality, therefore farmers should visit or be present close to the production area. To overcome these problems, application of remote monitoring and control of crop production environment has been increasing. Wireless monitoring and control systems have used CDMA, internet, and smart phone communications. Levels of technology adoption are different for farmers' needs for their cropping systems. In this paper, potential of wireless remote monitoring of protected agricultural environment using CDMA SMS text messages was reported. Monitoring variables were outside weather (precipitation, wind direction and velocity, temperature, and humidity), inside ambient condition (temperature, humidity, $CO_2$ level, and light intensity), irrigation status (irrigation flow rate and pressure), and soil condition (volumetric water content and matric potential). Scenarios and data formats for environment monitoring were devised, tested, and compared. Results of this study would provide useful information for adoption of wireless remote monitoring techniques by farmers.

• 한국축산시설환경학회지
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• 제12권1호
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• pp.41-44
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• 2006

2중필름 온실계사에서 육계를 사육하였을 때 발생하는 계분을 처리할 수 있는 수동 교반형 퇴비화시스템을 개발하였으며, 교반빈도가 퇴비화 온도에 미치는 효과를 분석하였다. 병원균 사멸에 필요한 $55^{\circ}C$ 이상의 온도를 유지한 기간은 무교반에서 88시간 1회/4일의 교반에서는 179 시간, 1회/2일의 교반에서는 200 시간으로 교반회수가 빈번할수록 그 기간이 길어지는 것으로 나타났다.

• 한국농공학회지
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• 제33권4호
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• pp.105-120
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• 1991

This study was performed to investigate the minimum safety factor of embankment in consideration of seismic coefficient by the psuedo-static analysis The variables were cohesion, the internal friction angle, angle of slope, height of seepage, height of embankment, depth of replacement The results obtained were compared with those by Fellenius method, simplified Bishop method and Janbu method. The results were summarized as follows: 1.The increasing rate of the minimum safety factor with the increasing of cohesion appeared larger in Fellenius method and Bishop method than in Janbu method. And that with the increasing of the internal friction angle appeared the lowest value in Janbu method. The minimum safety factor was influenced larger on the internal friction angle than on cohesion. 2.The variation of the minimum safety factor with the height of seepage at 0m and 5 m was nearly similar to Fellenius method, Bishop method and Janbu method. On the other hand, it was decreased suddenly at 25 m. 3.The minimum safety factor with the height of embankment was decreased remarkably under 10 m with the increasing of seismic coefficient. But, it was decreased slowly more than 10 m. As the height of embankment was low, the influence of cohesion appeared larger. 4.In heigher case of the depth of replacement, the phenomenon of reduction of the minimum safety factor appeared remarkably with seismic coefficient increased. And in lower case of the depth of replacement, the minimum safety factor was similar in Fellenius method and Bishop mehtod. But it appeared larger in Bishop method and Janbu method than in Fellenius method with the depth of replacement increased. 5.As the cohesion and the internal friction angle were large, the phenomenon of reduction of the minimum safety factor with the increasing of seismic coefficient appeared remarkably. Also, the influence of seismic coefficient in minimum safety factor appeared larger with the soil parameter increased. 6.When the seismic coefficient was considerated, investigation of the structural body on the slope stability appeared profitably in Fellenius method and Janbu method than in Bishop method.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.166-171
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• 2008

We cannot imagine any more the environment and energy problems are separated from our lives. The various attempts to solve these problems are made all over the world. In this study it was performed to analyze a different heating and cooling load depending on the earth-sheltering method and kind of soils by using TRNSYS 16 as the first step to establish the design guidelines for earth-sheltered architecture, one of the eco-friendly and low energy consuming building types. After performing this simulation, we found the result like this. It is the most lowest load in case of all of walls and roof being earth-sheltered. But considering of the load reduction rate, the effect of earth-sheltering the exterior vertical wall is more efficient for load reduction than the one of earth-sheltering a roof. And we got a lower thermal load in case of a lower heat conductivity of soil. Afterwards we will conduct a further study for boundary condition at earth-sheltered surface and the simulation analysis about the sensitivity variables. The final goal of this study is preparing the design guidelines for earth-sheltered architecture. so we will contribute to building energy saving.

• 한국물환경학회지
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• 제25권5호
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• pp.792-802
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• 2009

The objective of this study is to construct the watershed management system with link of the non-point sources model and to estimate delivery ratio duration curves for various pollutants. For the total water pollution load management system, non-point source model should be performed with the study of the characteristic about non-point sources and loadings of non-point source and the allotment of pollutant in each area. In this study, daily flow rates and delivered pollutant loads of Nakdong river basin are simulated with modified TANK model and minimum variance unbiased estimator and SWAT model. Based on the simulation results, flow duration curves, load duration curves, and delivery ratio duration curves have been established. Then GIS analysis is performed to obtain several hydrological geomorphic characteristics such as watershed area, stream length, watershed slope and runoff curve number. As a result, the SWAT simulation results show good agreements in terms of discharge, BOD, TN, TP but for more exact simulation should be kept studying about variables and parameters which are needed for simulation. And as a result of the characteristic discharges, pollutants loading with the runoff and delivery ratios, non-point sources effects were higher than point sources effects in the small-scale test bed of Nakdong river basin.

• 한국지리정보학회지
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• 제2권3호
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• pp.46-59
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• 1999

원격탐사는 넓은 지역에 대한 수문학적 상태나 변화량을 관측할 수 있는 시 공간적인 수문인자나 변수들에 대한 정보를 제공할 수 있다. 특히, 지표면 알베도, 식생정보 및 지표면 온도 분포등 유역의 수자원을 효율적으로 관리하기 위한 수문 인자들의 공간적인 분포를 파악할 수 있다. 본 논문에서는 수자원의 공간적인 분포를 파악하기 위해 필수적으로 요구되는 지표면 수문인자의 시 공간적인 변화 특성을 분석하였다. 수문인자의 변화 분석을 위해서 1995년도 금강 상류의 보청천 유역에 대해서 획득된 5개의 Landsat TM 자료를 이용하였으며, COST 모델을 이용하여 대기보정을 수행하였다. 연구결과, 토양중에 포함된 수분의 양과 태양고도각의 변화에 따라 알베도가 크게 변화하는 것으로 나타났으며, Landsat TM 자료로부터 추출된 지표면 온도와 기상관측을 통해서 얻어진 대기온도 사이의 차이가 $2.5^{\circ}C$ 내지 $3.86^{\circ}C$로 나타났다.

• 산업기술연구
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• 제3권
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• pp.53-63
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• 1983

The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; Pf=M/N N : Total number of trials M : Total number of failures Some of the conclusions derived from the case study include; 1. Three dimensional factors of safety are generally much higher than 2-D factors of safety. However situations appear to exist where the 3-D factor of safety can be lower than the 2-D factor of safety. 2. The F3/F2 ratio appears to be quite sensitive to c and ${\phi}$ and to the shape of the 3-D shear surface and the slope but not to be to the unit weight of soil. 3. In cases that strength parameters are assumed to be normal variated and beta variated, the relationships between safety factor and the probability of failure are fairly consistent, regardless of the shape of the 3-D shear surface and the slope. 4. As the c-value is increased, the probability of failure for the same safety factor is increased and as the ${\phi}-value$ is increased, the probability of failure for the same safety factor is decreased.