• Journal of Korean Society for Geospatial Information Science
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• v.4 no.1 s.6
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• pp.115-119
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• 1996

odel). One of important tasks for hydrological analysis is the division of watershed. It can be an essential factor amThe main objective of this study is to extract of the geometric characteristics of the Pyongchang River basin, headwaters of the South Ran River. A GIS is capable of extracting various hydrological factors from DEM(digital elevation mong various geometric characteristics of watershed. In this study, watershed itself and other geometric factors of watershed are extracted from DEM by using a GIS technique. The manual process of tasks to obtain geometric characteristics of watershed is automated. by using the function of ARC/INFO software as a GIS package. Scanned data is used for this study and it is converted to DEM data Various forms of representation of spatial data are handled in main modules and a GRID module of ARC/INFO. A GRID module is used on a stream in order to define watershed boundary, so it would be possible to obtain the watersheds. Also, a flowdirection, stream networks and others are generated. The results show that GIS can aid watershed management and research and surveillance. Also the geometric characteristics as parameters of watershed can be quantified by a using GIS technique. Resonable results can be obtained as compared with conventional graphic methods.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.4
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• pp.3-9
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• 2007

Recently, the efforts of systematic understanding and utilization of geographic phenomenon for human life as a important factor among activity of mankind are increasing. It is necessary to express topography connected with space. Especially, the technology of geographic analysis using DEM can supply the information rapidly and accurately about elevation and terrain slope of the subject area under the necessity of high 3D quality geographic information. In this study, creating more precise DEM derived from LiDAR data, quantitative analysis on the subject area about elevation and terrain slope is done under comparison with Digital Topographic map Scale 1:1000. LiDAR data is more detailed than Digital Topographic map to express the elevation of the subject area ($39.89{\sim}77.48m$), and terrain slope by analysis using DEM derived from LiDAR data come out minutely about 90%. It can be concluded that the LiDAR data is very applicable and accurate for 3D topographic terrain slope analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.271-271
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• 2011

최근의 유출해석은 지리정보체계(GIS, Geographic Information System) 및 지형자료(DEM, Digital Elevation Model 등) 구축의 발달로 대부분 격자 기반의 분포형 강우-유출 모형을 통해 이루어지고 있으며, Rodriguez-Iturbe and Valdes (1979)에 의해 소개된 통계물리학적 접근방법인 지형학적 순간단위도(GIUH)모형 역시 DEM을 기반으로 한 연구가 꾸준히 진행되어 온 실정이다(Maidment, 1993; D'odorico and Rigon, 2003; Di Lazzaro, 2010). 이러한 격자 기반 모형들은 대부분 8방향 최급경사에 기초한 흐름방향도를 기반으로 물의 유동을 표현한다. 8방향법에 의해 결정된 흐름방향도를 이용할 경우 각 격자 중심에서 유역출구 까지의 배수로경로길이를 비교적 쉽고, 빠르게 계산할 수 있다는 장점을 가지나, 공간해상도(격자 규모)에 따라 상이한 결과를 나타내는 것을 예상할 수 있다. 따라서 본 연구에서는 DEM의 공간해상도에 따른 배수경로길이의 통계적 변화양상을 살펴보고, 이로부터 실제 수문사상의 통계적 특성과 Di Lazzaro(2010)의 특성유속산정 공식을 이용해 지표면과 하천의 특성유속을 산정하였다. 산정된 특성유속들을 D'odorico and Rigon(2003)이 제시한 값과 비교함으로써 격자 기반의 GIUH 모형의 적용에 있어서 적정 공간해상도를 찾고자 하였다. 대상유역으로는 국제수문개발계획(IHP, International Hydrological Project)의 금강수계 보청천 유역 중 이평수위국을 출구로하는 소유역을 선정하였으며, DEM의 공간해상도는 수치지형도의 축척을 고려하여 1: 5,000의 경우 5, 10, 15, 20m를, 1: 25,000의 경우 20, 30, 50, 100, 150, 200m로 결정하였다. 분석 결과 격자 형태 GIUH의 특성유속을 산정을 위한 적정 공간해상도는 1:5,000의 경우 5m를, 1:25,000의 경우에는 20～50m의 범위를 적용하는 것이 타당할 것으로 판단된다.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.78-78
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• 1998

The purpose of this research is to develop a CAD-based program for data analysis of digital elevation model(DEM) on the aspect of landscape assessment. When handling DEM data as a visual simulation of topographic landscape, it is basic interest to analyze visible area and visualize visual sensitivity distributions. In reference with landscape assessment, more intuitive and interactive visualizing tools are needed, specially in area of visual approach. For adaptability to landscape assessment, algorithmic approaches to visibility analysis and concepts for visual sensitivity calculation in this study were based on processing techniques of entity data control functions used in AutoCAD drawing database. Also, for the purpose of quantitative analysis, grid-type 3DFACE entities were adopted as mesh unit of DEM structure. Developed programs are composed of main part named VSI written in AutoLISP and two of interface modules written in dialog control language(DCL0 for user-oriented interactive usage. Definitions of camera points(view points) and target points(or observed area) are available alternatively in combined methods of representing scenic landscape, scenery, and sequential landscape. In the case of scene landscape(single camera to fixed target point), only visibility analysis in available. And total visibility, frequency of cumulative visibility, and visual sensitivity analysis are available in other cases. Visual sensitivity was thought as view angle(3 dimensional observed visual area) and the strengths were classified in user defined level referring to statistical characteristics of distribution. Visibility analysis routine of the VSI was proved to be more effective in the accuracy and time comparing with similar modules of existing AutoCAD third utility.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.135-135
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• 2011

지구온난화와 이상기후에 따라 최근 우리나라를 둘러싼 기후패턴의 변화가 가속화되고 있으며 한반도는 장마기간이 소강상태를 보이는 반면, 장마 후 국지성 집중호우가 증가하고 태풍이 내습하는 현상이 빈번해짐으로써 홍수에 대한 위험과 피해규모도 증가하고 있다. 특히 도시지역에서는 강우규모가 배수시스템의 용량을 초과하거나, 하천수위 상승으로 관로 내에 역류가 발생하는 등 우수 배제 기능을 제대로 수행하지 못할 경우 발생하는 지표침수로 인해 심각한 인명 및 재산피해가 발생하고 있다. 실제로 현재 홍수해석 및 홍수위험지도 작성시 내수시스템을 반영하지 않아 침수면적 및 범위의 오차가 존재하며 홍수위험지도 작성시 내수범람과 외수범람을 따로 고려하는 문제점이 있다. 따라서 도시 침수 해석시 내수시스템을 반영한 정확한 침수심 및 침수면적계산뿐만 아니라 이상기후에 대비한 복합적 요인으로 인한 침수해석이 필요하다. 따라서 본 연구에서는 하천해석을 위해 1차원 하천 해석 모형인 FLDWAV모형을 적용하고 가상의 제방 파제 시나리오를 통하여 외수범람 영향을 구하였으며, 배수시스템의 SWMM모형과 제내지에서 내수와 외수범람의 영향을 고려한 DEM기반의 2차원 범람해석을 연계한 Dual-Drainage모형에 대하여 외수범람 영향에 따른 흐름의 양상, 침수심, 침수위 등을 분석하였다. 개발한 모형에 대한 적용성을 검토하기 위하여 대구 신암5동 유역을 선정하였고 대상유역의 수치지도를 활용하여 정형 격자 20m 크기로 지형자료를 구성하였으며, 건물의 영향도 고려하기 위해 DEM에 건물자료를 합성하였다. 침수해석 결과 내수시스템의 영향을 고려하지 않을 때가 고려하였을 때 보다 Node(맨홀)에서의 재유입의 영향으로 인하여 최대 침수심이 더 높게 나왔으며 침수면적도 넓게 나타나는 것을 확인하였고, 기존의 홍수위험지도 작성시 외수침수와 내수침수를 구분하여 해석하였던 것을 본 연구에서 통합하여 외수범람의 영향을 고려한 통합침수해석을 실시하여 내수에서 발생할 수 있는 유출량과 내수시스템의 월류량 등에 대한 고려가 없는 외수침수만 해석시 보다 최대침수심이 더 높게 나타났으며 침수면적 또한 넓게 나타남을 알 수 있었다. 본 연구를 통해서 도시홍수, 돌발홍수 등의 발생시 정확한 도시 침수 해석이 가능하며 도시침수구역에 대한 적절한 예 경보 및 피난대책 수립에 활용될 수 있을 것으로 사료된다. 또한 국내의 홍수위험지도나 도시 침수해석과 연계하여 선행시간을 확보한 정확도 높은 홍수정보시스템 구축에 크게 기여할 것으로 판단된다.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3197-3202
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• 2007

An analysis program for pedestrian flow has been developed to investigate the flow patterns of passenger in railway stations. Analysis algorithms for pedestrian flow based on DEM(Discrete Element Method) are newly developed. There are lots of similarity between particle-laden two phase flow and passenger flow. The velocity component of 1st phase corresponds to the unit vector of calculation cell, each particle to passenger, volume fraction to population density and the particle velocity to the walking velocity, etc. And, the walking velocity of passenger is also represented by the function of population density. Key algorithms are developed to determine the position of passenger, population density and numbering to each passenger. By using the developed program, we compared the simulation results of the effects of the location and size of exit and elapsed time.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.51-58
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• 2001

The Distinct Element Method (DEM) was used to analyze the stability of jointed rock slope, of which dimension are about 200m(length), 60m(height), $55^{\circ}$ dip. The Barton-Bandis joint model was used, as a constitutive model. The parameters such as JRC and spatial distribution characteristics of discontinuities were acquired through field investigation. Three different cases such as $51^{\circ}$, $45^{\circ}$ and $38^{\circ}$ in angle of rock slope were analyzed to decide a stable slope. To keep the jointed rock slope safely, it is proposed to reduce the height of slope from 60m to 48m and to reduce the angle of the from $55^{\circ}$ to $38^{\circ}$ too.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.751-758
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• 2005

In this study, the Discrete Element Code was applied to the analysis of falling rock blocks. The simulation was performed using the PFC2D computer code. Falling rock blocks should be applied as additional force to each others. The force affect the motion of falling rock blocks. This was used to find out the behavior of each blocks. This study revealed that the DEM can successfully capture the behavior of falling rock blocks.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.4
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• pp.267-273
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• 2005

Stereo image analysis has been an important tool for reconstructing 3D terrain. By In its nature, occlusion is one of difficulties Ive cannot avoid in stereo matching. This paper presents a study on occlusion detection by employing LRC(Left-Right Check) and OCC(Occlusion Constraint) and how we can improve the accuracy of DEM(Digital Elevation Model) y using interpolated data into the detected occluded area. Experimental results show that these method can effectively detect occluded regions and improve the accuarcy of DEM using the occlusion detection.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2001.04a
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• pp.241-247
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• 2001

A Fire Safety Evaluation Module(FSEM), which quantitatively evaluates the risk of evacuees when fire occurs in buildings or ships, is presented in this paper. The developed FSEM can be applied to multi-room structure. Basic input data for the FSEM are prepared by fire model and evacuation model. CFAST which is one of the existing fire models is used as fire model and MonteDEM evacuation model was developed for evacuation model, respectively. MonteDEM evacuation model makes use of distinct element method and Monte-Carlo simulation, and it can also take into consideration ground inclination by ship motions in order to simulate the real situation of evacuation. Some typical situations are modelled for illustrative examples and quantitative assessment of evacuee's risk under fire accident is carried out.