• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.6
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• pp.975-980
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• 2020

To protect wireless sensor networks (WSNs), various key distribution and management schemes have been proposed. However, most of them conducted simulations and experiments for performance evaluation by considering only the two-dimensional (2D) environments. In this paper, we investigate the effect of real-world three-dimensional (3D) topographic features on the key pre-distribution schemes for WSNs. For this purpose, we analyze and compare the performance of three pairwise key pre-distribution schemes in 2D and 3D environments: full pairwise (FP), random pairwise (RP), and full and random pairwise (FRP) schemes. For the experiments, we employ a network simulator NS-3 and 3D graphic tools such as Blender and Unity. As a result, we confirm that there was a difference in the performance of each scheme according to the actual 3D terrain and that the location-based FRP that considers deployment errors, has the highest efficiency in many aspects.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.2
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• pp.109-116
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• 2005

3D Spatial Data, namely 3D Urban CG model express the building, road, river in virtual world and accumulate, manage the data in the GIS system. It is important infrastructure which expected in many usages. Recently 3D CG urban model needs much manual effort, time and costs to build them. In this paper, we introduce the integration of GIS, CG and automatic production of the $\lceil$3D Spatial Data Infrastructure$\rfloor$. This system make filtering, divide the polygon, generate the outlines of the GIS building map, design the graphic and property information and finally make automatic 3D CG models.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.453-461
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• 2009

Camera monitoring of topographical changes of intertidal flat was performed at Daehang-ri mud flat outside Semangeum sea dike No. 1, where creation of mud flat was reported after sea dike construction. Ground survey on the mud flat is often limited only to points or few line surveys because of difficulty of walking and limitation of working hours by flood/ebb. This study uses natures of tide that the water lines moving on the intertidal flat during a flood indicate depth contours between low and high tide. Ground coordinates for the water lines extracted from the consecutive images of intertidal flat are calculated and information of topography is acquired by integrating all the water line data. Analysis of 6 camera monitoring data between September 2005 and September 2009 shows 0.127 m deposition per year on the average and variation of deposition/erosion in space and time.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1998.10a
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• pp.50-52
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• 1998

• Proceedings of the Korean Information Science Society Conference
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• 1999.10a
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• pp.27-29
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• 1999

가상현실 시스템에 대한 연구들은 대부분 현실세계 데이터를 컴퓨팅 세계의 데이터로 변환하기 위한 효율적인 방법론에 대한 연구가 주를 이루고 있다. 지리정보시스템(GIS)의 경우 정확한 실사를 통한 지리정보의 확보와 그래픽 시각화를 통한 신뢰성 있는 데이터의 제공을 주요 목적으로 삼는다. 본 논문은 지리정보시스템의 데이터모델을 기반으로 3차원 시각화를 위한 지형 데이터 모델과 가상 이미징 객체모델을 소개한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.832-836
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• 2009

공유수면을 간척 또는 매립하여 국토를 확장하여 산업화 도시화에 따른 토지수요 용도변경에 대처하여 국가발전의 균형을 유지하는 목적으로 수행하는 간척사업 시설중 중요한 시설인 배수갑문은 외수(해수)의 차단 및 내수배제를 통한 침수피해 경감의 역할을 수행하고 있다. '02년 태풍 "루사" 등 수공구조물의 설계빈도를 초과하는 폭우 발생으로 인한 홍수피해가 발생하고 배수갑문 설계시보다 유입홍수량이 증가하여 홍수시 수위가 계획홍수위 이상으로 형성되는 경우가 많아 이를 해결하기 위하여 배수갑문의 확장사업이 실시되고 있다. 그 첫 번째 사업으로 아산만방조제 배수갑문의 확장을 실시하였다. 아산만방조재 신설 배수갑문의 위치가 연약지반으로 형성되어 있어 신설 배수갑문을 통한 방류시 고속의 수류로 인한 바다측 물받이공 하류부의 세굴이 발생할 가능성이 크며, 이로 인한 배수갑문의 붕괴 우려가 있다. 그러므로 이를 방지하기 위하여 배수갑문 하류에 정수지형 물받이공을 설치하여 고속으로 방류되는 방류수의 유속을 저감시켜 세굴의 발생이 최소화하여 안정성이 확보되도록 하였다. 정수지형 물받이공의 효과 및 안정성을 검증하기 위하여 3차원 수치해석 FLOW-3D모형을 적용하여 수평물받이공과 정수지형 물받이공의 유속차이를 비교분석하였다. 분석한 결과 정수지 말단부에서 정수지 시점부와 비교하여 유속감소는 최대 약 49%, 평균 약 39%의 유속 감세효과를 나타내는 것으로 나타나 정수지형 물받이공을 통한 세굴 감소효과로 아산만방조제 배수갑문의 세굴에 의한 안정성은 확보되는 것으로 나타났다.

• 한국지형공간정보학회:학술대회논문집
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• 2002.03a
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• pp.156-161
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• 2002

자연공원의 체계적인 관리를 위해서는 효율적인 자료수집과 처리, 그리고 합리적인 분석과정이 필요하며, 이러한 관점에서 지형공간정보체계와 위성원격탐사를 이용하는 공원관리 및 관광안내시스템의 개발이 요구되는 시점이다. 본 연구에서는 금오산 도립공원구역을 사례연구지역으로 GSIS(Geo-Spatial Information System)기법을 도입하여 수치지형도, 주제도, 위성영상 등으로부터 도형자료 및 비도형자료를 수집 처리하였다. DEM 생성을 통하여 얻어진 경사도, 사면방향, 지형단면, 지질 분석 등 주제별 지형분석을 행하였다. Landsat TM 위성자료로부터 토지피복분류와 NDVI 식생활력도를 추출하였고, 이 자료들로부터 GSIS 데이터베이스를 구축하였다. 또한 대상지역을 포함하는 Im 해상도의 IKONOS 위성자료를 처리하여 영상지도를 작성하고 DEM과 중합하여 3D 시각화를 구현하였다. 위성영상지도 및 3차원 경관도상에 주요 등산로 벡터자료를 중첩하여 표현하고, 5개 루트의 주요 등산로를 따라 3D 경관 및 문화재, 관리시설 등을 포함하는 동영상 파일을 제작하였다. 본 연구의 결과는 개발과 보존의 중도를 취하는 자연공원의 적정 토지이용을 위한 사전평가 자료 및 Web 기반 관광안내시스템을 구축하기 위한 기본데이터로 활용될 수 있을 것이다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.5
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• pp.485-491
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• 2010

Acquisition of information on failure slope, which may cause apprehension of second hand damage, requires acquisition of fast and accurate topographical data and efficient expression in indirect surveying method without accessing as needed. Therefore, in this study, the images on the intended area were photographed through hovering in the air by approaching collapsed road cut slope with the use of unmanned helicopter photography system. As a result of comparing the points observed by no prism total station and the 10 coordinate points analyzed through image analysis, the averages of absolute values were shown to be 0.056m in X axis direction, 0.082m in Y axis direction and 0.066m Z axis direction. In addition, the RMSE of the error for 10 points of test points were 0.015636m in X axis direction, 0.021319m in Y axis direction and 0.018734m in Z axis direction. Therefore, this method can determine the range of slope and longitudinal and cross sections of each slope in dangerous area that cannot be approached in relational image matching method for the terrains of such collapsed cut slope.

• Journal of the Korean association of regional geographers
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• v.9 no.2
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• pp.203-216
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• 2003

The process of constructing coastal digital elevation model(DEM), for the 3 dimensional analysis, is composed by abstracting land layers for land elevation and water depth, reprojecting UTM, relocating geographical grid, and interpolating works. The geomorphic set of shallow sea, including tidal current, tidal zone deposition, and water depth distribution, was analyzed by eye search of Landsat TM image, masking of land zone, band combination and regression analysis. Some horizontal differences, between combined DEM and surveyed data of shallow sea, was corrected for analysis. Analyzed geomorphic elements are stream channel, alluvial fan, coastal terrace, tidal current. and shallow sea bank. Results of analysis present that transported fluvial materials influence tidal sedimentation, especially from Gahwacheon river, for the role of artificial draining flooding waters from Jinyang Reservoir, almost in the summer season. In the coastal area with less tidal current, more fine materials are deposited. The influence of currental deposition are higher on small pockets with west coast of well developed terraces. The lower skirt of alluvial fans developed into the tidal zone of shallow sea. Small pocket type bays are closed by coastal current, and less influenced from tidal deposition. The bank of Jinju Bay are developed originally from submerging of remnant erosional mountain ranges, and play on the role of trapping fine materials.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.3
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• pp.27-32
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• 2007

3D based information is demanded increasingly as cities grow three dimensionally and buildings become large and complex. The use of 3D GIS is also getting attention as fundamental data for ubiquitous computing applications such as location-based guidance, path finding and emergency escaping. However, most 3D modeling techniques are focused on the visualization of buildings or terrains and do not have topological structures required in spatial analyses. In this paper, we introduce a method to incorporate topological relationship into 3D models by combining 2D GIS layers and 3D model. We divide indoor spaces of a 3D model into discrete objects and then define the relationship with corresponding features in 2D GIS layers through database records. We also show how to construct hallways network in the 2D-3D integrated building model. Finally, we test different cases of route finding situations inside a building such as normal origin-destination path finding and emergency evacuation.