• Proceedings of the KSME Conference
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• 2005.11a
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• pp.63.2-63.2
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• 2005

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.570-570
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• 2016

홍수해석을 위해서는 DEM, 토지피복도, 토양도 등을 이용해서 대상 유역의 수문지형학적 매개변수를 도출해야 한다. 이때 북한과 같은 비접근 지역이나, 지상 관측에 의한 자료가 부족한 해외 지역에 대한 유출해석을 위해서는 대상 지역에 대한 상세한 자료를 얻기 어려우므로, 위성영상이나 전지구 데이터베이스 등과 같은 글로벌 자료를 이용하는 것이 대안이 될 수 있다. 글로벌 지형공간 자료로는 ASTER GDEM과 같은 DEM, Global Map과 같은 토지피복도, HWSD(Harmonized World Soil Database)와 같은 토양도를 이용할 수 있다. 본 연구에서는 이 중 HWSD의 적용성을 평가하였다. HWSD는 UN FAO(Food and Agriculture Organization of the United Nations)의 토지이용변경 프로그램에 따른 지도와 지역 및 국가 토양데이터베이스를 조합해서 만들어 졌으며, 30 arc-second(약 1km)의 해상도를 가진다. 유출해석은 물리적 분포형 모형인 GRM(Grid based Rainfall-runoff Model)을 이용하였으며, 낙동강 수계의 향석 수위관측소 유역을 대상으로 2008년과 2009년에 발생한 2개의 수문사상을 이용하여 연구를 진행하였다. 토양도를 제외한 자료(DEM, 토지피복도 등)는 모두 국내에서 구축된 자료를 이용하였다. 우리나라의 정밀토양도를 이용해서 보정된 모형(매개변수)에 HWSD 자료를 적용한 유출해석 결과, 두 사상에서 모두 유량이 크게 모의되었다. 이는 HWSD에서는 유역 전체가 양토(수리전도도 0.34cm/h)로 정밀토양도(향석 유역 평균 수리전도도 1.07cm/h)에 비해 약 1/3의 수리전도도 값을 가지고, 정밀토양도를 적용한 경우의 평균 토양심은 70cm이지만 HWSD에서는 37cm로 상대적으로 작기 때문에 토양 침투량은 작아지고, 유출량이 크게 계산되는 것으로 판단된다. HWSD를 이용한 모형 보정에서는 토양 수리전도도와 토양심 매개변수를 중심으로 보정하였으며, 그 결과 관측 유량을 잘 재현할 수 있었다. 위성영상을 이용해서 구축되는 토지피복도와는 달리, 토양정보는 원시 자료가 구축된 지역에 따라서 구축방법, 정확도 등에서 크게 차이가 날 수 있다. 그러므로 글로벌 자료를 이용한 유출해석에서는 토양 자료의 적용 및 이와 관련된 매개변수의 주의가 필요할 것으로 판단된다.

• Tunnel and Underground Space
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• v.9 no.2
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• pp.102-113
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• 1999

Two-dimensional and three-dimensional DEM programs, UDEC and 3DEC, were used to investigate the mechanical stability of the conceptual design of deposition drift and deposition holes constructed in a crystalline rock mass. From the simulations, the influence of discontinuities, the number of deposition holes, and deposition hole interval on the stability of deposition drift and deposition holes could be determined. From the two-dimensional and three-dimensional analysis. it was concluded that three-dimensional analysis should be carried 7ut fur deriving reliable conclusions. Even though the deposition hole interval changed from 8 m to 3 m, which did not damage the mechanical stability of the deposition drift.

• Journal of Korea Water Resources Association
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• v.52 no.8
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• pp.515-529
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• 2019

Geospatial information for river network and watershed boundary have played a fundamental roles in terms of river management, planning and design, hydrological and hydraulic analysis. Irrespective of their importance, the lack of punctual update and improper maintenance in currently available river-related geospatial information systems has revealed inconsistency issues between individual systems and spatial inaccuracy with regard to reflecting dynamically transferring riverine geography. Given that digital elevation models (DEMs) of high spatial resolution enabling to reproduce precise river network are only available adjacent to national rivers, DEMs with poor spatial resolution lead to generate unreliable river network information and thereby reduce their extensible applicabilities. This study first of all evaluated published spatial information available in Korea with respect to their spatial accuracy and consistency, and also provides a methodology and tool to modify existing low resolution of DEMs by means of striation of conventional or digitized river network to replicate input river network in various degree of further delineation. The tool named FSND was designed to be operated in ArcGIS ModelBuilder which ensures to automatically simulate river network striation to DEMs and delineation with different flow accumulation threshold. The FNSD was successfully validated in Seom River basin to identify its replication of given river network manually digitized based on recent aerial photograph in conjunction with a DEM with 30 meter spatial resolution. With the derived accuracy of reproducibility, substantiation of a various order of river network and watershed boundary from the striated DEM posed tangible possibility for highly extending DEMs with low resolution to be capable of producing reliable riverine spatial information subsequently.

• Tunnel and Underground Space
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• v.11 no.4
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• pp.344-351
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• 2001

In the tunnelling by blasting, the calculations of charge weight and the estimations of blasting effect have been simply carried out by empirical formulas. Also, it has been rare to consider the impact energy of blasting in numerical analyses. Thus in this study a numerical modeling technique of blasting load is developed and used with the 2 dimensional distinct element method(DEM) to consider the nonlinear behaviour of discontinuous underground structures. TD examine and verify its applicability of the numerical model to actual problems, a blasting of tunnel under an embankment is numerically analysed with DEM. It is examined that the behavior of circumference structures, the displacements of above- and under-ground structures, and the propagation of particle velocities can be known by this numerical analysis. As a result, the blasting load model, proposed by this study, can be applied to actual problems. This model applied with DEM can be used in the examination of structural stability.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.804-811
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• 2019

This study was performed the real motion and DEM simulation of ball motion using three different types of grinding media with different size and materials in media formation for optimization of process conditions in a traditional ball mill (media ball mill). In the simulation, the rotational speed of the mill, the material of the medium, the velocity of the medium, and the coefficient of friction between the media and the wall of pot were fixed into the actual experimental conditions. The motion of various kinds of grinding media was quantitatively measured by setting the grinding zone defined in the present study on the photographs taken and the snapshot images analyzed in the simulation. In addition, we observed the quantitatively measured value and the changed morphology of the sample and examined the correlation. Therefore, it is suggested to optimize the grinding media which has the greatest influence on the grinding zone under specific experimental conditions.

• Tunnel and Underground Space
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• v.11 no.3
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• pp.270-278
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• 2001

Two numerical methods such as DEM and FDM were adopted to analysis of rock slope stability, of which dimensions are about 150 m(length), 58 m(height), 70°dip, in Halla limestone mine. For this rock slope stability analysis, strength reduction method was used to calculate the safety factor of slope through numerical method. To keep the rock slope safely, it is proposed to reduce the height of the rock slope from 58 m to 45 m and to reduce the angle of the slope from 70°to 55°, too.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1201-1205
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• 2010

최근 몇 년간 기후변화에 의해 기상이변이 발생하고 있으며 이에 따른 집중호우로 인한 홍수피해가 심각한 수준으로 발생하고 있다. 이에 수문기상학적 요소와 특성인자들의 정확한 상호 연관성의 규명과 공간적 변동성 해석은 강우-유출 모형에서 발생하는 불확실성을 감소시키는데 중요한 요소라고 할 수 있다. 이에 본 연구에서는 레이더 강우 격자 해상도와 지형인자 격자 해상도에 따라 강우-유출모형이 어떻게 반응하는지 분석하였다. 본 연구에서는 가-분포 강우-유출 모형인 ModClark 모형을 이용하여 강원도 인제군의 내린천 유역을 대상으로 광덕산 레이더자료를 이용하였다. ModClak 모형 구성을 위한 GIS 지형공간 자료는 30m, 150m, 250m, 350m 격자크기의 DEM을 사용하였으며, 2006년 7월 14일부터 7월 17일까지의 관측레이더 강우자료를 500m, 1km, 2km, 5km, 10km 사용하여 유출모의를 실시하고, 각각의 격자해상도에 따른 모의 결과를 비교하기 위해 유출수문곡선을 작성하고 유출량 변화를 모의하였다. 분석 결과 첨두유량 및 유출체적에 대해서는 DEM 30m~150m, Grid 500m~2,000m 크기의 격자일 때 가장 최적의 유출 모의를 한 것으로 분석되었으며, 통계적 분석에 의한 분석결과에서는 모든 DEM 격자는 Grid 500m인 경우, 모든 Grid 격자는 DEM 30m인 경우에 모형의 적합성이 높은 것으로 나타났고, 민감도 산정 결과 지수 등급이 높은 DEM이 분포형 모형의 결과 값에 큰 영향을 주는 것으로 분석되었다.

• Journal of The Geomorphological Association of Korea
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• v.20 no.4
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• pp.85-99
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• 2013

The objective of this paper is to analyze the spatial distribution of errors in the DEM generated using waterlines from multi-temporal remote sensing data and to assess flood vulnerability. Unlike conventional research in which only global statistics of errors have been generated, this paper tries to quantitatively analyze the spatial distribution of errors from a probabilistic viewpoint using geostatistical simulation. The initial DEM in Baramarae tidal flats was generated by corrected tidal level values and waterlines extracted from multi-temporal Landsat data in 2010s. When compared with the ground measurement height data, overall the waterline-based DEM underestimated the actual heights and local variations of the errors were observed. By applying sequential Gaussian simulation based on spatial autocorrelation of DEM errors, multiple alternative error distributions were generated. After correcting errors in the initial DEM with simulated error distributions, probabilities for flood vulnerability were estimated under the sea level rise scenarios of IPCC SERS. The error analysis methodology based on geostatistical simulation could model both uncertainties of the error assessment and error propagation problems in a probabilistic framework. Therefore, it is expected that the error analysis methodology applied in this paper will be effectively used for the probabilistic assessment of errors included in various thematic maps as well as the error assessment of waterline-based DEMs in tidal flats.

• Spatial Information Research
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• v.10 no.2
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• pp.263-273
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• 2002

This paper presents desirable water environmental management to a closed watershed. In order to obtain spatially distributed environmental information, GIS data have been used. Elevation data are used to extract stream channels automatically and to divide networks of a watershed. A Digital Elevation Model (DEM) has been developed, validated, and adopted to estimate the runoff of total nitrogen pollutant from watershed. This GIS-linked model can be applied effectively to the watersheds with many sub-streams, and for the estimation of pollutant runoff considering land use change.