• Title/Summary/Keyword: Topography analysis

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A study on the utilization of drones and aerial photographs for searching ruins with a focus on topographic analysis (유적탐색을 위한 드론과 항공사진의 활용방안 연구)

  • Heo, Ui-Haeng;Lee, Wal-Yeong
    • Korean Journal of Heritage: History & Science
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    • v.51 no.2
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    • pp.22-37
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    • 2018
  • Unmanned aerial vehicles (UAV) have attracted considerable attention both at home and abroad. The UAV is equipped with a camera that shoots images, which is advantageous for access to areas where archaeological investigations are not possible. Moreover, it is possible to acquire three-dimensional spatial image information by modeling the terrain through aerial photographing, and it is possible to specify the interpretation of the terrain of the survey area. In addition, if we understand the change of the terrain through comparison with past aerial photographs, it will be very helpful to grasp the existence of the ruins. The terrain modeling for searching these remains can be divided into two parts. First, we acquire the aerial photographs of the current terrain using the drone. Then, using image registration and post-processing, we complete the image-joining and terrain-modeling using past aerial photographs. The completed modeled terrain can be used to derive several analytical results. In the present terrain modeling, terrain analysis such as DSM, DTM, and altitude analysis can be performed to roughly grasp the characteristics of the change in the form, quality, and micro-topography. Past terrain modeling of aerial photographs allows us to understand the shape of landforms and micro-topography in wetlands. When verified with actual findings and overlapping data on the modelling of each terrain, it is believed that changes in hill shapes and buried Microform can be identified as helpful when used in low-flying applications. Thus, modeling data using aerial photographs is useful for identifying the reasons for the inability to carry out archaeological surveys, the existence of terrain and ruins in a wide area, and to discuss the preservation process of the ruins. Furthermore, it is possible to provide various themes, such as cadastral maps and land use maps, through comparison of past and present topographical data. However, it is certain that it will function as a new investigation methodology for the exploration of ruins in order to discover archaeological cultural properties.

Exploring the Priority Area of Policy-based Forest Road Construction using Spatial Information (공간정보를 활용한 산림정책 기반 임도시공 우선지역 선정 연구)

  • Sang-Wook, LEE;Chul-Hee, LIM
    • Journal of the Korean Association of Geographic Information Studies
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    • v.25 no.4
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    • pp.94-106
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    • 2022
  • In order to increase timber self-sufficiency, Korea's 6th Basic Forest Plan aims to increase the density of forest roads to 12.8 m ha-1 by 2037. However, due to rapid re-forestation, current management infrastructure is insufficient, with just 4.8 m ha-1 of forest roads in 2017. This is partly due to time and cost limitations on the process of forest road feasibility evaluation, which considers factors such as topography and forest conditions. To solve this problem, we propose an eco-friendly and efficient forest road network planning method using a geographic information system (GIS), which can evaluate a potential road site remotely based on spatial information. To facilitate such planning, this study identifies forest road construction priorities that can be evaluated using spatial information, such as topography, forest type and forest disasters. A method of predicting the optimal route to connect a forest road with existing roads is also derived. Overlapping analysis was performed using GIS-MCE (which combines GIS with multi-criteria evaluation), targeting the areas of Cheongsong-gun and Buk-gu, Pohang-si, which have a low forest-road density. Each factor affecting the suitability of a proposed new forest road site was assigned a cost, creating a cost surface that facilitates prioritization for each forest type. The forest path's optimal route was then derived using least-cost path analysis. The results of this process were 30 forestry site recommendations in Cheongsong-gun and one in Buk-gu, Pohang-si; this would increase forest road density for the managed forest sites in Cheongsong-gun from 1.58 m ha-1 to 2.55 m ha-1. This evaluation method can contribute to the policy of increasing timber self-sufficiency by providing clear guidelines for selecting forest road construction sites and predicting optimal connections to the existing road network.

Computation of Criterion Rainfall for Urban Flood by Logistic Regression (로지스틱 회귀에 의한 도시 침수발생의 한계강우량 산정)

  • Kim, Hyun Il;Han, Kun Yeun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.39 no.6
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    • pp.713-723
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    • 2019
  • Due to the climate change and various rainfall pattern, it is difficult to estimate a rainfall criterion which cause inundation for urban drainage districts. It is necessary to examine the result of inundation analysis by considering the detailed topography of the watershed, drainage system, and various rainfall scenarios. In this study, various rainfall scenarios were considered with the probabilistic rainfall and Huff's time distribution method in order to identify the rainfall characteristics affecting the inundation of the Hyoja drainage basin. Flood analysis was performed with SWMM and two-dimensional inundation analysis model and the parameters of SWMM were optimized with flood trace map and GA (Genetic Algorithm). By linking SWMM and two-dimensional flood analysis model, the fitness ratio between the existing flood trace and simulated inundation map turned out to be 73.6 %. The occurrence of inundation according to each rainfall scenario was identified, and the rainfall criterion could be estimated through the logistic regression method. By reflecting the results of one/two dimensional flood analysis, and AWS/ASOS data during 2010~2018, the rainfall criteria for inundation occurrence were estimated as 72.04 mm, 146.83 mm, 203.06 mm in 1, 2 and 3 hr of rainfall duration repectively. The rainfall criterion could be re-estimated through input of continuously observed rainfall data. The methodology presented in this study is expected to provide a quantitative rainfall criterion for urban drainage area, and the basic data for flood warning and evacuation plan.

Vegetation of Moojechi Moor in Ulsan: Syntaxonomy and Syndynamics (울산 무제치늪의 식생: 군락분류와 군락동태)

  • 김종원;김중훈
    • The Korean Journal of Ecology
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    • v.26 no.5
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    • pp.281-287
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    • 2003
  • We present the first analysis of moor vegetation on the Moojechi of Ulsan including syntaxonomy and syndynamics. We classified plant communities according to the Braun-Blanquet approach. In order to better understand ecological alteration processes and changing species compositions along successional gradients we also examined synecological differences using Principal Coordinate Analysis(PCoA) in terms of moisture gradient, species richness, and community structure. Classification resulted in one association and five plant communities occupying distinct moor habitats: Hypericum laxum-Eleocharis acicularis for. longiseta community, Drosera rotundifolia-Eleocharis congesta community, Platanthero-Molinietum japonicae ass. nova hoc loco, Molinia japonica-Alnus japonica community, Miscanthus sinensis-Pinus densiflora community, and Convallaria keiskei-Quercus serrata community. Due to synecological correspondences and floristic similarities in supraregional perspective, Platanthero-Molinietum can be assigned to existing higher syntaxonomic units of Molinion and Molinietalia in Braun-Blanquet system, established in Japan. We propose to extend their range and designate the new class Molinietea japonicae representative to the intermediate moor (Zwischenmoor) vegetation in Northeast Asia. PCoA resulted in four types showing a sequencess of succession: Needle spike-rush type, moor-grass type (incl. alder forest type), eulalia type, and oak forest type. A combination of edaphic conditions (soil eutrphication and soil moisture) and hydrologic patterns of moor ecosystem related to topography, occurring as result of external geophysical forces, controls inter alia spatial patterns and floristic compositions of moor plant communities.

Disaster Prevention Planning through Analysis of Debris Flow Vulnerability Based on Mountain Basin Features (산지유역 기반의 토석류 취약성 분석을 통한 재해방지 계획수립 연구)

  • Kim, Man-Il;Lee, Moon-Se;Hong, Kwan-Pyo
    • The Journal of Engineering Geology
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    • v.27 no.4
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    • pp.393-403
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    • 2017
  • Mountain disasters in Korea have caused massive social and economic damage. During the period 2005-2014 there has been an annual average of 7 deaths and disaster recovery costs of 79.8 billion won in the country's 4393 ha of mountainous areas. The primary mountain disasters are landslides on mountain slopes, and secondary debris flows can spread along mountain streams, damaging facilities and settlements in lower areas. Typhoons and local rainfall can cause such disasters, while anthropogenic factors include development that damages the mountainous terrain. The study area was divided into three basins. For each basin, a debris flow vulnerability assessment method was proposed considering FLO-2D analysis results and the local topography, geology, and forestation. To establish an in situ investigation, analysis, and evaluation plan for potential mountain disasters, we selected mountain basins that are potentially vulnerable to mountain disasters through analysis of their mountain slopes and streams. This work suggests the establishment of a comprehensive plan for disaster prevention based on a mountain basin feature.

Framework for Optimum Scale Determination for Small Hydropower Development Using Economic Analysis (경제성분석에 의한 소수력 개발의 최적규모 결정 방안)

  • Kim, Kil-Ho;Yi, Choong-Sung;Lee, Jin-Hee;Shim, Myung-Pil
    • Journal of Korea Water Resources Association
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    • v.40 no.12
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    • pp.995-1005
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    • 2007
  • This study presents a framework for optimum scale determination for small hydropower development in a river basin. The framework includes the construction of hydrology and topography data, the simulation of hydropower operation, the economic analysis, and the determination of optimum scale of the small hydropower. The optimum scale of design flow and facility are determined by Net Present Value among economic analysis indices. The investment cost is estimated by the cost function derived from the construction cost of existing small hydropower plants. The benefit from power generation is estimated by the price announced by government. The presented framework is applied to the two potential sites in Cho River basin for the dam and run-of-river type of plants. Finally, the sensitivity analysis for a design flow and scale of the plant is performed for the each site. The usage of the framework presented in the study is highly expected for the estimation of potential hydropower resources or the decision support tool for a proprietor by estimating the optimum scale and economical feasibility in advance.

Numerical Analysis of Debris Flow Using Drone Images and NFLOW (드론 영상 및 NFLOW를 활용한 토석류 수치해석 연구)

  • Lee, Seungjoo;Lim, Hyuntaek;Lim, Moojae;Lee, Eungbeom;Lee, Kang-Il;Kim, Yongseong
    • Journal of the Korean Geosynthetics Society
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    • v.19 no.3
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    • pp.1-8
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    • 2020
  • In this study, numerical analysis of debris flow was performed using the SPH (Smoothed Particle Hydrodynamics) technique to analyze the mechanism of debris flow, and the applicability of soil parameters was verified by comparison with previous studies. In addition, after performing aerial photographic survey using a drone, a topographic model was created based on this survey to check the applicability of the site to the valley part of Jagul Mountain basin. And after numerical analysis of debris flow was performed using NFLOW, and the result was compared and analyzed with the existing satellite image based method. As a result of this study, the numerical analysis method using drone image and NFLOW was found to have a higher applicability to predicting the impact of debris flow, because it can reflect the actual topography better than the existing method based on satellite imagery. Therefore, it is considered that this study can be used as basic data to establish the preventive measures for debris flow such as location selection of the eruption control dam.

Solar Access and Shading Analysis of Traditional Building Using a Solar Trajectory Meter (태양 궤적 측정기를 이용한 전통 건축물 음영 분석)

  • Kim, Myoung Nam;Park, Ji Hee
    • Journal of Conservation Science
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    • v.37 no.2
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    • pp.90-100
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    • 2021
  • Outdoor cultural buildings and their accessories receive different amounts of solar radiation depending on their location's latitude, azimuth, and tilt. Shading is also affected by the surrounding terrain and objects, necessitating individual and quantitative shading analysis. In July 2019, this study conducted a shading analysis on the tops, midpoints, and bottoms of wooden pillars in the azimuth of Cheongpunggak, a traditional building in South Korea's National Research Institute of Cultural Heritage. The shading analysis found that the solar access/shade predicted by the solar trajectory meter was 30 minutes slower than measured in the field. The highest solar access and solar radiation levels came from the south, followed by the west, east, and north. The pillars' bases received the highest solar access and solar radiation, followed by their midpoints and tops. Solar access was high at tilt 90°, but solar radiation was high at tilt 0°, due to the light-collection efficiency and the irradiance. Shading on the pillars' tops was caused by the roof eaves, while shading on the midpoints and bases were affected by the surrounding pillars, topography, and other objects. Simultaneous solar access at the tops, midpoints, and bottoms was possible for 365 days for the northwest, west, and southwest pillars but only from October to March for the south and southeast pillars.

Analysis of the Type of Narrative Structure of the '10 Million Films' ('천만 영화'의 서사구조 유형 분석)

  • Tae, Ji-Ho;Kim, DaeKeun
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.7
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    • pp.287-298
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    • 2020
  • The purpose of this study is to analyze the narrative structure and types of films that has attracted more than 10 million viewers ('10 million films') among films released in Korea, and deal with the implications of the current Korean film industry. To this end, this study investigated the relationship between films and their narrative as a product of the film industry. To approach this, We dealt with the features of structuralist analysis and archetype or mythological narrative analysis. For a detailed analysis, a total of 27 films of "10 million films" were categorized using Northrop Frye's original narrative analysis method. As a result of the study, 13 comedy structures, 7 romance structures, 4 tragic structures, and 3 irony and satire structures. It was confirmed that the "comedy" and "romance" structures had a high percentage of all 10 million films, and occupied the top ranks in the box office rankings. In conclusion, this study confirmed the narrative rules and customs of films hitting Korean box offices, and through this, it was possible to examine a rough topography of the film consumption of the public in the Korean film industry. This can be said to provide a clue as to how the narrative of the film should be constructed when producing a film from an industrial perspective.

Estimation of Support Working Expenses for Dam Area using GIS Spatial Analysis (GIS 공간분석을 이용한 댐 주변지역 지원사업비 산정)

  • Hwang, Eui-Ho;Lee, Geun-Sang;Chae, Hyuo-Suck;Koh, Deuk-Koo
    • Journal of the Korean Association of Geographic Information Studies
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    • v.8 no.4
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    • pp.24-32
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    • 2005
  • Budget distribution system suporting dam area was changed largely in 2005, and thus, population survey and area calculation for dam and needed to be performed based upon the new criteria. According to the former regulations, dam area was confined to inside of 5km from the H.W.L-line. However, new regulations divide it into two categories : inside and outside of catchment area within 2km from the H. W. L-line and those belong to 2~5km from the same line. In this study, topography, DEM, TIN and Hydrological Unit Map were build for the analysis of the Namgang Dam area. It shows that analysis of dam area using GIS methods produces a good results to be used for rational distribution of budget.

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