• Korean Journal of Remote Sensing
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• v.23 no.6
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• pp.567-573
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• 2007

Tidal channel development is influenced by sediment type, grain size, composition and tidal current. Tidal channels are usually characterized by channel formation, density and shape. Quantitative analysis of tidal channels using remotely sensed data have rarely been studied. The objective of this study is to quantify tidal channels in terms of fractal dimension and compare different inter-tidal channel patterns and compare with DEM (Digital Elevation Model). For the fractal analysis, we used box counting method which had been successfully applied to streams, coastlines and others linear features. For a study, the southern part of Ganghwado tidal flats was selected which know for high dynamics of tidal currents and vast tidal flats. This area has different widths and lengths of tidal channels. IKONOS was used for extracting tidal channels, and the box counting method was applied to obtain fractal dimensions (D) for each tidal channel. Yeochari area where channels showed less dense development and low DEM had low fractal dimenwion near $1.00{\sim}1.20$. Area (near Donggumdo and Yeongjongdo) of dendritic channel pattern and high DEM resulted in high fractal dimension near $1.20{\sim}1.35$. The difference of fractal dimensions according to channel development in tidal flats is relatively large enough to use as an index for tidal channel classification. Therefore we could conclude that fractal dimension, channel development and DEM in tidal channel has high correlation. Using fractal dimension, channel development and DEM, it would be possible to quantify the tidal channel development in association with surface characteristics.

• Journal of Korean Society for Geospatial Information Science
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• v.13 no.3 s.33
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• pp.33-40
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• 2005

The aim of remotely sensed data classification is to produce the best accuracy map of the earth surface assigning each pixel to its appropriate category of the real-world. The classification of satellite multi-spectral image data has become tool for generating ground cover map. Many classification methods exist. In this study, MLC(Maximum Likelihood Classification), ANN(Artificial neural network), SVM(Support Vector Machine), Naive Bayes classifier algorithms are compared using IKONOS image of the part of Dalsung Gun, Daegu area. Two preprocessing methods are performed-PCA(Principal component analysis), ICA(Independent Component Analysis). Boosting algorithms also performed. By the combination of appropriate feature selection pre-processing and classifier, the best results were obtained.

• Korean Journal of Remote Sensing
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• v.11 no.1
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• pp.1-17
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• 1995

Using remotely sensed data(MOS-1) and other spatial data such as aerial photos and topographic maps, 10 kind of thematic layers were prepared with Arc/Info system for watershed management of Nam Khane River, northern part of Laos. The characteristics of landuse distribution of some criteria which like village, sub-basin, elevation and slope were clarified by overlaying each layer. Therefore, statistic data including shifting cultivation area were produced from database layer. Through the manipulation of some data of each layer, suitable area for permanent paddy cropping converted from the fallow and shifting cultivation area was extracted.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.114-114
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• 2023

기상레이더는 대류권의 기상 관측에 널리 사용되며, 기상예보를 비롯하여 항공, 농업, 수문학 등 다양한 분야에서 활용하고 있다. 기상레이더센터는 SSPA(Solid State Power Amplifier) 기반 X-Band 주파수대역(9GHz)을 사용하는 연구용 소형기상레이더 관측망을 운영하고 있다. 주로 수도권 저층 대기에서 발생하는 위험 기상현상을 1분 단위로 빠르게 관측하면서 정확한 강수 정보생산을 위한 연구를 수행하고 있다. 레이더 관측 자료는 전파를 이용하여 넓은 범위에 분포하는 눈, 비, 우박 등 대기수상체를 관측하여, 강수량 추정을 통해 강수 정보를 생산한다. 이에 따라 레이더 관측 자료의 정확성과 신뢰도를 높이기 위해서 레이더 품질관리 기술 적용은 필수적이다. 기상레이더센터는 소형기상레이더로 관측한 이중편파 자료의 효과적인 품질관리를 위한 각종 자료처리 모듈을 개발하여, 실시간 자료처리 프로그램에 적용하였다. 우선, 저층 대기 관측 시 기상에코와 더불어 강한 반사도로 나타나는 지형에코를 판별하는 모듈과 선형 또는 쐐기형태의 전파간섭에코를 비롯한 비기상에코를 효과적으로 제거하는 기술을 개발하였다. 다음으로, X-Band 주파수대역 기상레이더 관측 자료의 취약점인 강한 강수 시 발생하는 반사도 감쇠 현상을 보정하기 위한 기술도 개발하였다. 소형기상레이더 품질관리 개발과 적용을 통하여 생산된 자료는 HSR(Hybrid Surface Rainfall), 레이더 강수량 추정, 대기수상체 등 다양한 기상 산출물 생산과 동시에 기상 감시 및 연구 분야에 효과적으로 활용하고 있다.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.1
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• pp.81-92
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• 2010

The purpose of this study is to find one of the standard scales of outside space. Fortunately, Korea has interesting old geographical name representing the environment where people feel comfortable by being enclosed by hills or mountains like in a room. The name of Chinese letter "谷" meaning valley is enunciated as "Gog", and Korean native equivalent word is "Sil." We thought we can find the standards of scale of the villages with name that ends with "Gog" or "Sil" by examining the scale of the village of the certain geographical name. We could collect 33 village's geographical names in Jin An Gun area, examined the scale, and considered the results from various aspects. The main conclusions are following: 1) Almost of the 33 villages with geographical names of "Gog", or "Sil" were surrounded by the hills of mountains, and the scales of the spaces surrounded were roughly 10~25ha. 2) Our ancestors felt comfortable be being enclosed with hills or mountains like in a room, and they have recognized the certain scale of the enclosed spaces. 3) After converting the 33 areas into squares for convenience, the scales of the spaces with the geographical name of "Gog" or "Sil" were roughly $300m{\times}300m{\sim}500m{\times}500m$.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.415-415
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• 2011

수문학 또는 하천유출은 크게 기후학적은 인자 (온도, 바람, 상대습도 등)나 지형학적 인자 (지표면 경사, 흙의 종류, 하천의 면적, 하천의 길이 등)들에 의해 결정된다. 지형학적 인자들 중인 하천의 면적 그리고 주하천의 길이에 의한 영향은 비첨두홍수량의 과 수문곡선의 모양에 크게 관여되어 있다. 일반적으로 유역형상이 좁고 주하천의 길이(유로연장)가 긴 하천의 경우 단위면적당 유출량과 시간과의 그래프에서 수문곡선은 넓고 낮은 형태 모습을 지니지만 유역의 형상이 넓고 주하천의 길이기 짧은 하천은 수문곡선이 좁고 높은 형태의 모습을 가진다. 이러한 유역형상의 차이에 따라 Horton (1932)은 유역의 면적과 주하천의 길이의 비로 형상계수 (Shape Factor)의 공식을 제시하였다. 유역면적에 비해 유로연장이 길면 형상계수가 작아지고 첨두홍수량이 작아지는 반면 유역면적에 비해 유로연장이 짧을수록 형상계수가 커져 첨두홍수량이 커지는 형상을 발견할 수 있다. 형상계수와 비첨두홍수량의 상관관계를 알아보기 위하여 상수 전용댐 안전성 대책 및 치수능력 증대 방안연구 (2008) 보고서에서 적용한 유역들을 비교하였다. 이 보고서에 있는 38개의 유역들 중에서 형상계수가 0< <1 인 유역들을 선택한 후 형상계수와 지속시간별 비첨두홍수량의 관계 그리고 유역면적과 지속시간별 비첨두홍수량의 관계를 도시하였다. 추세선에 의한 결정계수인 $R^2$ 의 값을 비교하여 형상계수와 비첨두홍수량과의 관계를 조명하였다. 또한, 형상계수에 따른 순간단위도의 첨두시간 및 첨두유량을 비교하기 위하여 유역면적이 $300m^2$내외이며, 서로 다른 형상계수를 갖는 유역을 선정하여 연구를 진행하였다. 대상유역의 관측값을 이용하여 Nash모형을 적용한 순간단위도를 산정하였으며, 형상계수에 따른 첨두시간 및 첨두유량의 비교분석을 수행하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.12 no.1
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• pp.35-42
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• 1994

This study aims to develop a hydrological information management system to manage the hydrological data of Han river integratedly. Various data related to hydrology such as water level, dams, the positions of the hydrological structures for Han river were collected and inputed to build the hydrological information management system. The Database Management System(DBMS) of Korea Water Resources Cooperation which is operated in the form of digits and characters was linked to the Geo-Spatial Information System to join positional information and digital information and to analyze the hydrological data using graphical techniques. Through this study, the positional errors which occurred when digital or characteristic informations were only used, were detected. And the hydrological information management system was presented to estimate the reliability of data related to water level among the hydrological information and to show the basis of output used to correct the data.

• Korean Journal of Remote Sensing
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• v.15 no.1
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• pp.61-71
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• 1999

Several physical phenomena on the sea surface are analyzed from SAR images of South Sea areas, Korea. Strong wave patterns propagating in southerly direction are seen in ERS-1 SAR image on October 11, 1994, and a wave directional spectrum is calculated from this image using the SAR modulation transfer function. RADARSAT SAR image of August 15, 1996 reveals internal waves in northern coastal waters of Cheju Island. Analysis indicates that the internal waves may have been generated by the tidal currents traveling over the shallow bottom of the stratified water in the summer during the tidal changeovers fro ebb to flood and shows patterns of trains of solitons. RADARSAT SAR image taken 3 days after the oil spill accident near Goeje Isalnd on April 3, 1997 detects distinct oil slicks from the accident area but also shows slicks near the coast caused by wind sheltering of coastal mountains and chemical-biological activities.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.1
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• pp.57-67
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• 2013

In Korea, there are debris-flow disasters induced by typhoon and localized torrential rainfall annually. There are particularly extensive debris-flow disasters in Gangwon-do because of its geomorphological characteristics; the extensive coverage of mountainous region, steep slope, and shallow soil. In this paper, we constructed a GIS database about topological characteristics of debris-flow basin in Gangwon-do by years of field survey. Also, we conducted frequency analysis based on this database with the digital forest type map and the digital soil map. We analyzed frequencies of debris-flow by simple count for topological characteristics, whereas we analyzed by considering an area ratio based on GIS for physiognomic and geologic characteristics. We used slope, aspect, width, depth and destruction shapes for analysis about topological characteristics of debris-flow basin. Also we used attributes of forest physiognomy, diameter, age, and density about physiognomic characteristics, and i n terms of geologic characteristics, we used attributes of drainage class, effective soil depth, subsoil properties, subsoil grave content, erosion class, parent material of soil, and topsoil properties. In consequence, we figured out topographic, forest physiognomic, and geologic characteristics of debris-flow basin. This result is applicable to establish a rational disaster prevention policy as a fundamental information.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.4
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• pp.59-71
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• 2019

In Mountainous Districts Management Act of Korea Forest Service, slope and elevation criteria are operated to regulate the indiscriminate use of risky land parcels when forestland is converted to other land use types. However, there is a limitation in considering topographical variation with only such two indices in the land parcel. Therefore, in order to supplement insufficient criteria, the slope type standard was developed using Catena, and the ecological condition improved terrain standards. Firstly, the ratio of 'risky slope' in a target forestland parcel was defined to decrease the risk of disasters such as landslides. Secondly, the standard of the ecological location condition was proposed as ecological score by integrating age, diameter and soil depth classes in the target forestland parcels. Thereby, we could prepare reasonable standards that can reduce forestland disasters and ecological damages, as suggesting new topographical and ecological assessment methods for forestland use conversion.