• Title/Summary/Keyword: watershed algorithm

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Analysis of Forest Structure Using LiDAR Data - A Case Study of Forest in Namchon-Dong, Osan - (LiDAR 데이터를 이용한 산림구조 분석 - 오산시 남촌동의 산림을 대상으로 -)

  • Lee, Dong-Kun;Ryu, Ji-Eun;Kim, Eun-Young;Jeon, Seong-Woo
    • Journal of Environmental Impact Assessment
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    • v.17 no.5
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    • pp.279-288
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    • 2008
  • Vertical forest distribution is one of the important factors to understand various ecological mechanism such as succession, disturbance and environmental effects. LiDAR data provide information, both the horizontal and vertical distribution of forest structure. The laser scanner survey provided a point cloud, in which the x, y, and z coordinates of the points are known. The objectives of this study were 1) to analyze factors of forest structure such as individual tree isolation, tree height, canopy closure and tree density using LiDAR data and 2) to compare the forest structure between outer and interior forest. The paper conducted to extract the individual tree using watershed algorithm and to interpolate using the first return of LiDAR data for yielding digital surface model (DSM). The results of the study show characters of edge such as more isolated individual trees, higher density, lower canopy closure, and lower tree height than those of interior forest. LiDAR data is to be useful for analyzing of forest structure. Further study should be undertaken with species for more accurate results.

Runoff Analysis by the Geomorphoclimatic Linear Reservoir Model (지형기후학적 선형저수지 모델에 의한 유출해석)

  • 조홍제
    • Water for future
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    • v.18 no.2
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    • pp.143-152
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    • 1985
  • A method is suggested for the reappearance of a surface runoff hudorgraph of a river basin by linking the hydrologic response of a catchment represented by the instantaneous unit hydrograph(IUH) with the Horton's empirical gemorphologic laws. The geomorphologic theory of the IUH developed by G. Itrube et al. and the geomorphoclimatic theory of the IUH developed by Bras et al. are used to derive the new hydrologic response function in consideration of geomorphologic parameters and climatic characteristics by applying to Sukekawa's rainfall-runoff model. The derived response function was tested for on some observed hydrographs in a natural watershed and showed promising, and by considering a drainage basin as m(1∼4) identical linear reservoir in series, it was founded that the model(m=2) is most applicable to predict hydrologic response regardless of the size of basins. A modelization algorithm of a basin using Sthahler's ordering scheme of drainage network will give good result in analysis of the surface runoff huydrograph by the method of this study.

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Video Data Scene Segmentation Method Using Region Segmentation (영역분할을 사용한 동영상 데이터 장면 분할 기법)

  • Yeom, Seong-Ju;Kim, U-Saeng
    • The KIPS Transactions:PartB
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    • v.8B no.5
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    • pp.493-500
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    • 2001
  • Video scene segmentation is fundamental role for content based video analysis. In this paper, we propose a new region based video scene segmentation method using continuity test for each object region which is segmented by the watershed algorithm for all frames in video data. For this purpose, we first classify video data segments into classes that are the dynamic and static sections according to the object movement rate by comparing the spatial and shape similarity of each region. And then, try to segment each sections by grouping each sections by comparing the neighbor section sections by comparing the neighbor section similarity. Because, this method uses the region which represented on object as a similarity measure, it can segment video scenes efficiently without undesirable fault alarms by illumination and partial changes.

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Groundwater Movement Analysis Using the WINFLOW Model (WINFLOW 모델을 이용한 지하수 유동해석)

  • 최윤영;안승섭;김재광
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.3
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    • pp.103-115
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    • 2003
  • This study examines groundwater movement system analysis and movement forecast algorithm using finite element method. The target is Cheongha-myeon area, Bukgu, Pohang-city which has many difficulties in water supply during drought period. From the comparison of the differences between obtained values by WINFlOW model and observed values, it is thought that groundwater head distribution under steady flow is reflected well at the level of reliability Groundwater movement of study area shows stable pattern from western watershed to eastern coastal area while flow path is dense and steep in the center of the coastal area. The results of particle tracing for each well show a comparatively straight line from the western boundary side to the observation position at the upper area of the well, and are analyzed as it diffuses according to getting closer to the coast at the lower area of the well. The result of effect circle examination attendant on pumping amount in study area shows variation tendency that groundwater head decreases at the side and the lower area more than at the upper area of the well when groundwater flows from west to east(coast). As mentioned above, satisfactory results of groundwater movement analysis using WINFlOW model, two dimensional groundwater movement analysis model, are obtained through the great decrease of physical uncertainty of groundwater movement system.

Classification Index for Landscape Type - focused on Natural and Rural landscape mapping - (경관유형 분류지표에 관한 연구 - 자연 및 농촌경관 유형도 작성을 중심으로 -)

  • Im, Seung-Bin;Seo, Jung-Hee;Piao, Xiang-Chun;Jeong, Yoon-Hee
    • Journal of Korean Society of Rural Planning
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    • v.13 no.1 s.34
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    • pp.41-50
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    • 2007
  • Recently, it is demanded to study about landscape. Landscape is an environment factor for improving life, a social resource for establishing image and identity of the area and also a tourist resource for earning profit. With this importance, landscape planning is being performed by local governments. However, classification for a rule about landscape planning is not prepared yet. For this purpose, classification of landscape is definitely required. Therefore, this article focuses on presenting method of classification Natural and Rural Landscape. We used Arcview 3.2 to draw watershed of the site, and calculated the percent of landform. We also took a picture which explain the landscape and made a survey of classifying the landscape. Due to this study, we were able to frame an algorithm of the landscape classification. This will contribute to classify the landscape type. This study needs more specific researches because it was supposed to target the entire Gyeonggi-Do however it only covered several regions. Through this results, it would be expected to develop the map of landscape character.

Characterizing the Spatial-temporal Distribution of Soil Moisture for Sulmachun Watershed Through a Continuous Monitoring (설마천 유역의 토양수분 장기 모니터링을 통한 토양수분 시공간 변화양상의 특성화)

  • Lee, Ga Young;Kim, Ki Hoon;Kim, Sang Hyun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2004.05b
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    • pp.209-214
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    • 2004
  • Time Domain Reflectometry with multiplex system has been installed to configure the spatial and temporal characteristics of soil moisture in a mountainous hillslope. An intensive surveying was performed to build a refined digital elevation model and flow determination algorithms with inverse surveying have been applied to establish an efficient soil monitoring system. Steady state wetness index, quasi-dynamic wetness index and fully dynamic wetness index have been calculated. Continuous monitoring of soil moisture data were analyized with wetness indices. Limitations and hydrological interpretations of this approach have beer discussed.

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A Proposal of Distribution Method for Inter-Regional Sewage Treatement Zone Using GIS and Gravity Model (GIS와 중력모형을 이용한 광역 하수처리권역 설정)

  • 하성룡;박대희
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • 1998.11a
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    • pp.20-25
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    • 1998
  • In order to support effective decision-making related to inter-sewage planning, this study proposes the spatial distribution method of inter-sewage treatement area using spatial analysis of GIS, Communication system of database, spatial interaction of Gravity model. Evalution Indexs are consist of economic, social/political and environmental condition value which are explained by the analysis of AHP algorithm ,based on opinion of related experts. Network module in Arc/Info is applied in order to find out minimum pipeline root in Miho river watershed, one of the sub-basin of Geum river basin. This value also is utilized for the construction of cost decay function in gravity model.

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Estimation of Spatial Evapotranspiration Using satellite images and SEBAL Model in Gyeongancheon watershed (위성영상과 SEBAL 모형을 이용한 경안천 유역의 공간증발산량 산정)

  • Ha, Rim;Shin, Hyung-Jin;Park, Min-Gi;Kim, Seong-Joon
    • Proceedings of the KSRS Conference
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    • 2009.03a
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    • pp.129-133
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    • 2009
  • 본 연구에서 소개할 SEBAL (Surface Energy Balance Algorithm for Land) (Bastiaanssen, 1995) 모형은 Landsat이나 NOAA 또는 MODIS 같은 원격탐사 위성으로부터 획득한 디지털 이미지 데이터(위성영상)를 이용하여, 지표에서 일어나는 증발산과 기타의 에너지 교환을 계산하는 이미지-프로세싱 모델이다. SEBAL 모형은 1995년 Bastiaanssen에 의해 처음 제안되었고, 미국의 Idaho 주립대학과 Idaho Department of Water Resources에서 NASA와 기업의 지원을 받아 활발히 연구 되었으며, 25개의 sub model들을 이용하여 지표의 증발산량과 기타 여러 에너지 교환을 계산한다. 여기서, 열적외선 방사, 표시 및 근적외선 측정은 Landsat 또는 기타 여러 위성영상을 통해 얻을 수 있으며, SEBAL 모형은 이러한 자료를 활용한다. 모형에서의 증발산량(ET)은 에너지 균형원리를 통해 pixel-by-pixel을 기준으로 계산되며, 본 연구에서 SEBAL 모형은 한강 유역 내의 경안천 유역 증발산량 map 생성을 위해 6개년도 지점 Landsat 위성영상을 이용하어 추정되었다. 연구의 목적은 SEBAL 모형을 통해 생성 된 30m 해상도의 공간 증발산량 map의 활용성 평가와 검증이며, 검증을 위해 FAO Penman-Monteith 공식을 이용하여 추정된 증발산량 값을 이용하였다. 그 결과, 오차가 2.7% 이내로 나타났다.

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A Complex Region Analysis Algorithm of Two Dimensional Electrophoresis Images Using Accumulated Gradients (누적 기울기를 이용한 2차원 전기영동 영상의 복잡영역 분석 알고리즘)

  • Kim, Mi-Ae;Yoon, Young-Woo
    • Journal of the Korea Society of Computer and Information
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    • v.14 no.7
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    • pp.41-47
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    • 2009
  • A solution to the problems of recognizing as one spot or detection failures for complex regions, in which many spots representing proteins are overlapped and saturated, is suggested. The accumulated gradients of each point in complex regions are calculated, and the resulting accumulated gradient image segmented using watershed technique. The suggested solution show better and efficient result than existing method for spot separation, detects more protein spots hidden in the image of 2-dimensional electrophoresis, and expands the scope of prediction.

Fast information extraction algorithm for object-based MPEG-4 conversion from MPEG-1,2 (MPEG-1,2로부터 객체 기반 MPEG-4 변환을 위한 고속 정보 추출 알고리즘)

  • 양종호;박성욱
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.41 no.3
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    • pp.91-102
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    • 2004
  • In this paper, a fast information extraction algorithm for object-based MPEG-4 application from MPEG-1,2 is proposed. For object-based MPEG-4 conversion, we need to extract such information as object-image, shape-image, macro-block motion vector, and header information from MPEG-1,2 bit-stream. If we use the extracted information, fast conversion for object-based MPEG-4 is possible. The proposed object extraction algerian has two important steps, namely the motion vector extraction from MPEG-1,2 bit-stream and the watershed algerian The algorithm extracts objects using user's assistance in the intra frame and tracks then in the following inter frames. If we have an unsatisfactory result for a fast moving object the user can intervene to connect the segmentation. The proposed algorithm consist of two steps, which are intra frame object extracting processing and inter frame tracking processing. Object extracting process is the step in which user extracts a semantic object directly by using the block classification and watersheds. Object tracking process is the step of the following the object in the subsequent frames. It is based on the boundary fitting method using motion vector, object-mask and modified watersheds. Experimental results show that the proposed method can achieve a fast conversion from the MPEG-1,2 bit-stream to the object-based MPEG-4 input.