• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.12 no.2
• /
• pp.96-106
• /
• 2000

Though the recent years, large scale structures have been built on offshore for utilization of coastal ocean space as offshore airport and marine terminals. Sometimes, those big scale structures, however, happened to act as significant barriers against waves and severe beach erosion would take place on the coast. The present study deals nearshore topography changes affected by construction of an offshore structure with different distance from the shore. The series of three dimensional movable bed experiments have been examined in detail. Moreover, in order to make clear the relation of nearshore currents and local erosions behind offshore structure, the nearshore currents are calculated by Boussinesq equation model and compared with the same scale condition of the physical model experiments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.3
• /
• pp.419-429
• /
• 1999

Identifying the boundary of the effective receiving power of waves is one of the most important factors for cell optimization. In this paper, we introduce a propagation loss prediction model which yields highly accurate prediction in very complex areas as Seoul where a mixture of many large buildings, small buildings, broad streets, narrow alleys, rivers and forests co-exist in an irregular arrangement. This prediction model is based on neural networks trained on field measurement data collected in the past. Using these data along with 3-D digital elevation maps and vector data for building structures, we extract the parameter values which mainly affect the amount of propagation loss. These parameter values are then used as the inputs to the neural network. Trained neural network becomes the approximated function of the propagation loss model which generalizes very well and can predict accurately in the regions not included in training the neural network. The experimental results show a superior performance over the other models in the cells operating in the city of Seoul.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.405-405
• /
• 2022

본 연구는 주암조절지댐 유역의 강우 빛 비강우시츨 포함한 장기간의 유역유출 및 지하수 이동에 따른 유량분석과 오염물질 부하 유입특성을 분석함으로써 유역의 오염물질을 선제적으로 관리하고 조절지댐내의 수질을 효과적으로 관리하기 위해서 수행되었다. Hydrological Simulation Program - Fortran (HSPF) 모델을 적용하기 위하여 주암조절지댐 유역의 복잡한 지형과 기상조건 및 오염원 자료를 반영하고 수질관리 대책을 수립하는 데 적용하고자 하였다. 주암조절지댐 유역은 환경부의 소유역 구분을 고려하여 28개의 유역으로 세분화하고 티센망도를 고려해 3개의 그룹으로 재차 분류하였다. 기상 자료는 연구대상지역의 직접측정자료의 한계로 여수와 광양 기상청의 자료를 사용하였으며, 강우 자료 또한 소유역 그룹에 맞춰 입력 자료로 사용하였다. HSPF 모델의 보정은 유량 및 수질 (총질소 및 총인)에 대하여 2017 ~ 2021년의 모니터링 실측자료를 대상으로 수행되었다. 보정 결과는 R², RMSE로 평가하였고, 보정된 HSPF 모델을 바탕으로 유역별 유량 및 수질에 영향을 미치는 주요 인자를 분석하였다. 본 연구의 결과는 주암조절지댐의 수질을 예측할 수 있는 3차원 수리-수질 모델의 입력자료로 활용될 예정이며, 추후 기후변화 영향을 고려한 상류 유역의 수질관리 계획 수립에 기여할 것으로 기대된다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.3B
• /
• pp.213-219
• /
• 2009

In densely urban areas, features such as the sewer system, buildings and river banks have an effect on flow dynamics and flood propagation, and will therefore be accounted for in the model set-up. While two-dimensional (2D) flood models of urban areas are at the forefront of current research into flood inundation mechanisms, they are however constrained by inadequate parameters of topography, and insufficient and inaccurate data. In this study, an urban flood model (overland flow, 2D urban flood flow and sewer flow) was combined and applied at Samcheok city which was damaged by inundation in 2002, in order to simulate inundation depth. The influence of buildings and pumping capacity was also analyzed to estimate the inundated depth in the study area. As a result, it was found that urban inundated depth are affected by pumping capacity directly and it increased about 20-30 cm on most of the modeled area with a building share rate of 0.2-0.6 per unit grid.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.25 no.6_2
• /
• pp.645-651
• /
• 2007

In general, contours in digital vector maps, which represent terrain characteristics and shape, are created by 3D digitizing the same height points using aerial photographs on the analytical or digital plotters with stereoscopic viewing. Hence, it requires lots of task, and subjective decision and experience of the operators. DTMs are generated indirectly by using contours since the national digital maps do not include digital terrain model (DTM) data. In this study, model key points which depict the important information about terrain characteristics were extracted from the contours. Further, determination of the efficient and flexible grid sizes were proposed to generate optimal DTM in terms of both quantitative and qualitative aspects. For this purpose, a progressive sampling technique was implemented, i.e., the smaller grid sizes are assigned for the mountainous areas where have large relief while the larger grid sizes are assigned for the relatively flat areas. In consequence, DTMs with multi-grid for difference areas could be generated instead of DTMs with a fixed grid size. The multi-grid DTMs reduce computations for data processing and provide fast display.

• Spatial Information Research
• /
• v.12 no.2
• /
• pp.137-149
• /
• 2004

For 3D modelling artificial objects with computers, we have to draw frames and paint the facet images on each side. In this paper, a geographic modelling system building automatically 3D geographic spaces using GIS data and real images of buildings is proposed. First, the 3D model of terrain is constructed by using TIN and DEM algorithms. The images of buildings are acquired with a camera and its position is estimated using vertical lines of the image and the GIS data. The height of the building is computed with the image and the position of the camera, which used for making up the frames of buildings. The 3D model of the building is obtained by detecting the facet iamges of the building and texture mapping them on the 3D frame. The proposed geographical modeling system is applied to real area and shows its effectiveness.

• Economic and Environmental Geology
• /
• v.19 no.4
• /
• pp.283-292
• /
• 1986

Finite element method with linear triangular and bilinear rectangular elements is applied to solve the three-dimensional potential distribution due to a point source of current located in or on the surface of the earth containing arbitrary two-dimensional resistivity distribution. The modeling technique developed in this paper is flexible to model conductive inhomogeneity and surface topographies, and more accurate to evaluate surface potentials than the conventional techniques using finite difference method. Since it is possible to reduce nodal points with acceptable accuracy, this modeling technique is very efficient and economic in terms of execution time and core space. A few geologic structures adequate to demonstrate above features are simulated in this paper.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.14 no.4
• /
• pp.54-62
• /
• 2011

At present, about 1.6 million bio-species have been discovered in the world. Approximately 30 thousand indigenes have been recorded in Korea and about fifteen thousand species of biology inhabit in Korea national park. Korea national park where has been lived 133 species at 60 percent of endangered species is a very important wildlife protection area. The construction of database about substantive distribution and habitat of wildlife is urgently needed to protect and manage endangered species. In this study, main habitats about animals were registered using GIS program in Jirisan National Park and 3 dimensional habitat map was produced. Also, new plan was suggested to preserve and manage animals in national parks by producing 3 dimensional habitat map. The habitat map was produced using coordinate file of animals, polygon file about boundary of national park, and ASTER GDEM. New conceptional animal habitat map will be used by means of the valuable information when the plans for preservation/management and habitat protection about animals are designed.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2003.10a
• /
• pp.231-235
• /
• 2003

실시간 동적 GPS 측위를 이용한 해저수심측량은 GPS 수신기가 이동중인 상태에서 신호단절 없이 연속적인 수심측정이 가능하며 등수심도와 등고선 제작에 정확한 위치를 결정할 수 있고, 음향측심기는 발사파와 수신파의 도달시간을 측정하여 수심을 관측할 수 있기 때문에 실시간으로 정확한 3차원 측량이 가능하다. 본 논문에서는 해안지역에 대한 지형 분석을 하기 위하여 기준점에 대한 정지관측을 실시하여 좌표변환계수를 산출하고, 이로부터 실시간 동적 GPS 측량과 음향측심기를 이용하여 해운대 해수욕장과 해안을 관측하였다. 1:1,200 축척의 수치지도에서 추출한 수치표고모델에서의 체적은 97953.9 ㎥이며, 실시간 동적 GPS와 음향측심기를 이용하여 추출한 수치표고모델에서의 체적은 95994.9 ㎥로 나타났다. 이는 수치지도에서의 체적과 측량결과의 체적이 단지 2.0%정도로 나타나 실시간 동적 GPS와 음향측심기의 결합에 의한 해저수심측량이 매우 성공적임을 알 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2023.05a
• /
• pp.131-131
• /
• 2023

지하수는 담수-염수 경계면의 형성 및 변동 특성, 지하수위 분포 및 변동특성에 따라 기저지하수, 준기저지하수, 상위지하수 등으로 구분된다. 이 중, 기저지하수는 담수(1,000g/cm³)와 염수(1,025g/cm³)의 비중 차이에 의해 담수가 염수 상부에 Ghyben-Herzberg 원리에 의해 부존한다. 본 연구에서는 부존 형태에 따른 지하수위 변동을 보고자 하였다. 먼저 이상화된 지형에서 부존형태에 따른 지하수위 변동의 영향을 확인하고자, OpenGeoSys 모형을 이용하여 3차원 수치모의를 수행하였다. 그 결과 상위지하수의 지하수위보다 기저지하수 조건에서의 지하수위가 낮아진 것을 확인할 수 있었다. 이는 부존 형태의 차이로 인해 발생되는 담수-염수 비중 차이가 지하수위 변동에 영향을 미친다는 것을 파악할 수 있었다. 또한, 실제 지형에 적용하여 지하수위의 변동성을 분석하기 위해서, 제주 남부 중서귀 유역을 대상으로 수치모의를 수행하였다. 모형 검증은 범위 내 4개의 관측지점에서의 2022년 지하수위 자료를 이용하였다. 검증된 모델에 염분 농도 조건을 추가하여 기저지하수를 형성하여 모의를 수행했다. 따라서 본 연구는 부존 형태의 차이로 인해 발생되는 담수-염수 비중 차이가 지하수위에 끼치는 영향을 파악할 수 있었다. 향후, 상위지하수에서 염수가 침입했을 때, 수위 저하에 따라 감소되는 지하수위량을 예측할 수 있을 것이라 기대된다.