• Title/Summary/Keyword: Topographic change

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Acoustic Stratigraphy and Sedimentary Processes in the KONOD-1 Area between the Clarion and Clipperton Fracture Zones, Northeastern Equatorial Pacific (북동태펑양 크라리온-크리퍼톤 균열대 사이 한국 망간노듈개발지역-1의 탄성파층서 및 퇴적작용)

  • Jeong, Kap-Sik;Han, Sang-Joon;Kim, Seong-Ryul
    • 한국해양학회지
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    • v.23 no.1
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    • pp.24-40
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    • 1988
  • In the Korea Ocean Nodule Development (KONOD)-1 area between the Clarion and Clipperton fracture zones of the northeastern equatorial Pacific, the pelagic sediment layer can be divided into two or three units on air-gun seismic profile. The acoustic units can be also correlated with those in the DSDP site 163 core. The topmost unit (unit I) is acoustically transparent and consists of zeolitic clay and radiolarian ooze of late Oligocene to middle Eocene age. Unit IIA is well-stratified and transparent in the lower part. consisting of the radiolarian ooze intercalated with chert beds and zeolitic clay of early Eocene to Paleocene age. Unit IIB is stratified with layers of silicified and compacted flinty-cherty nannofossil chalk (late Cretaceous) on top of the acoustic basement. Units I and IIA form the Line Islands Formation that overlies an unnamed formation of unit lIB. The entire layers and the unit I layer propressively thin northward, except near the Line Islands Ridge. The distribution of sediment layer has been controlled by the equatorial Cenozoic CCD and the northward spreading of the Pacific plate. The change of CCD corresponding to the subsidence and migration of the plate has determined the sediment composition of the DSDP 163 core passed across the equator of high sedimentation suite. The late Cretaceous sedimentary layer (unit IIB) in the 163 core was formed above the CCD south of the equator. The unit IIA resulted from rapid subsidence of the Pacific plate below the CCD in the Paleocene. The unit IIA is seen only in the west of 149 W. Both the units IIA and I were probably formed during the Pacific plate passing and after leaving the equatorial region respectively since early Eocene. In the south of the KONOD-l area, the unit I was redistributed by bottom current, a branch of the Antarctic Bottom Water flowing eastward guided by the Clipperton fracture zone. The activities of bottom currents were prolonged for a long geological time. Turbidite layers occur more than 350 km from the Hawaiian Ridge to near the Clarion fracture zone. They originated directly from the Hawaiian Ridge, filling the topographic lows.

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The Improvement of Real-time Updating Methods of the National Base Map Using Building Layout Drawing (건물배치도를 이용한 국가기본도 수시수정 방법 개선)

  • Shin, Chang Soo;Park, Moon Jae;Choi, Yun Soo;Baek, kyu Yeong;Kim, Jaemyeong
    • Journal of Cadastre & Land InformatiX
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    • v.48 no.1
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    • pp.139-151
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    • 2018
  • The National Base Map construction consists of the regular correction work of dividing the whole country into two regions and carrying out the modification Plotting by aerial photographs every two years as well as the real time updating work of correcting the major change feature within two weeks by the field survey and the As-Built Drawing. In the case of the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS) used for real time updating work of the National base map, the coordinate transformation error is included in the positional error when applied to the National Base Map based on the World Geodetic Reference System as the coordinate system based on the Regional Geodetic Reference System. In addition, National Base Map is registered based on the outline(eaves line) of the building in the Digital Topographic Map, and the Cadastral and Architecture are registered based on the building center line. Therefore, the Building Object management standard is inconsistent. In order to investigate the improvement method, the network RTK survey was conducted directly on a location of the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS) and the problems were analyzed by comparing with the plane plotting position reference in National Base Map. In the case of the general structure with the difference on the Building center line and the eaves line, beside the location information was different also the difference in the ratio of the building object was different between Building center line and the eave. In conclusion, it is necessary to provide the Base data of the double layer of the Building center line and the outline of the building(eaves line) in order to utilize the Building Layout Drawing of Korea Real estate Administration intelligence System(KRAS). In addition, it is necessary to study an organic map update process that can acquire the up-to-dateness and the accuracy at the same time.

Analysis of National Vertical Datum Connection Using Tidal Bench Mark (기본수준점을 이용한 국가수직기준연계 분석 연구)

  • Yoon, Ha Su;Chang, Min Chol;Choi, Yun Soo;Huh, Yong
    • Journal of Korean Society for Geospatial Information Science
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    • v.22 no.3
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    • pp.47-56
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    • 2014
  • Recently, the velocity of sea-level rising has increased due to the global warming and the natural disasters have been occurred many times. Therefore, there are various demands for the integration of vertical reference datums for the ocean and land areas in order to develop a coastal area and prevent a natural disaster. Currently, the vertical datum for the ocean area refers to Local Mean Sea Level(LMSL) and the vertical datum for the land area is based on Incheon Mean Sea Level(IMSL). This study uses 31 points of Tidal Gauge Bench Mark (TGBM) in order to compares and analyzes the geometric heights referring LMSL, IMSL, and the nationally determined geoid surface. 11 points of comparable data are biased more than 10 cm when the geometric heights are compared. It seems to be caused by the inflow of river, the relocation of Tidal Gauge Station, and the topographic change by harbor construction. Also, this study analyze the inclination of sea surface which is the difference between IMSL and LMSL, and it shows the inclination of sea surface increases from the western to southern, and eastern seas. In this study, it is shown that TGBM can be used to integrate vertical datums for the ocean and land areas. In order to integrate the vertical datums, there need more surveying data connecting the ocean to the land area, also cooperation between Korea Hydrographic and Oceanographic Administration and National Geographic Information Institute. It is expected that the integrated vertical datum can be applied to the development of coastal area and the preventative of natural disaster.

A Study on the Distributional Characteristics of Unminable Manganese Nodule Area from the Investigation of Seafloor Photographs (해저면 영상 관찰을 통한 망간단괴 채광 장애지역 분포 특성 연구)

  • Kim, Hyun-Sub;Jung, Mee-Sook;Park, Cheong-Kee;Ko, Young-Tak
    • Geophysics and Geophysical Exploration
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    • v.10 no.3
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    • pp.173-182
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    • 2007
  • It is well known that manganese nodules enriched with valuable metals are abundantly distributed in the abyssal plain area in the Clarion-Clipperton (C-C) fracture zone of the northeast Pacific. Previous studies using deep-sea camera (DSC) system reported different observations about the relation of seafloor topographic change and nodule abundance, and they were sometimes contradictory. Moreover, proper foundation on the estimation of DSC underwater position, was not introduced clearly. The variability of the mining condition of manganese nodule according to seafloor topography was examined in the Korea Deep Ocean Study (KODOS) area, located in the C-C zone. In this paper, it is suggested that the utilization of deep towing system such as DSC is very useful approach to whom are interested in analysing the distributional characteristics of manganese nodule filed and in selecting promising minable area. To this purpose, nodule abundance and detailed bathymetry were acquired using deep-sea camera system and multi-beam echo sounder, respectively on the seamount free abyssal hill area of southern part ($132^{\circ}10'W$, $9^{\circ}45'N$) in KODOS regime. Some reasonable assumptions were introduced to enhance the accuracy of estimated DSC sampling position. The accuracy in the result of estimated underwater position was verified indirectly through the comparison of measured abundances on the crossing point of neighboring DSC tracks. From the recorded seafloor images, not only nodules and sediments but cracks and cliffs could be also found frequently. The positions of these probable unminable area were calculated by use of the recorded time being encountered with them from the seafloor images of DSC. The results suggest that the unminable areas are mostly distributed on the slope sides and hill tops, where nodule collector can not travel over.

The Interpretation of Korean Traditional Garden in the View of Complexity Theory - Focusing on Soswaewon Garden - ('복잡성(Complexity) 이론'에 의한 한국 전통정원의 해석 - 한국의 명원 소쇄원을 중심으로 -)

  • Jang, Il-Young;Shin, Sang-Sup
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.28 no.2
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    • pp.75-85
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    • 2010
  • The purpose of this study is to attempt new analysis on Soswaewon Garden(瀟灑園) where is Korea's traditional garden, focusing on which the tendency of its change is a relational-formation tool similar to the Eastern Mode of Thought, with paying attention to conversion as the new view of world. Accordingly, the aim is to reanalyze by connecting with Soswaewon Garden based on the theory of complexity, which tries to look at the whole through relationship rather than characteristics in individual components. Given summarizing findings, those are as follows. First, it was found that complexity shown in space and open system of physical dimension was characterized by 'event(situation)', 'non-determination' and 'homogeneous relationships between part and whole', and a variety of techniques introduced the nature positively. In particular, it was found that there were many cases of topographic usage, since the Soswaewon Garden selected its construction site proactively and was a product from architectural works in compliance with a given flow of natural topography. This has a nature of open text in the situation of emergent behaviors. Second, it was found that complexity shown in experiences and open system on the invisible dimension was characterized primarily by 'event(situation)' and 'relationships of interactive response between actors and environment', and various techniques appeared as a space for interactive combination of nature and daily experiences. This is typical of bilateral harmony based on interactions between subject and object, and between mankind and nature, and becomes also a space to accommodate temporary emergent behaviors in our life. Third, the compositional elements are reconstituted as space of organic property with dismantling steady relations. Especially, 'Soswaewon Garden's 48 poems(瀟灑園四十八詠)' will be the origin of the emotionally spatial experience to the current performers. Ultimately, the performer in the space of Soswaewon Garden simultaneously becomes a creator of space, and will generate new space with intertextuality with environment. Therefore, Soswaewon Garden becomes a place of binding me and the other together while maintaining mutual relationship based on organic thinking between a human being and nature and between the whole and a part.

Estimation of the Three-dimensional Vegetation Landscape of the Donhwamun Gate Area in Changdeokgung Palace through the Rubber Sheeting Transformation of (<동궐도(東闕圖)>의 러버쉬팅변환을 통한 창덕궁 돈화문 지역의 입체적 식생 경관 추정)

  • Lee, Jae-Yong
    • Korean Journal of Heritage: History & Science
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    • v.51 no.2
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    • pp.138-153
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    • 2018
  • The purpose of this study was to analyze , which was made in the late Joseon Dynasty to specify the vegetation landscape of the Donhwamun Gate area in Changdeokgung Palace. The study results can be summarized as below. First, based on "Jieziyuan Huazhuan(芥子園畵傳)", the introductory book of tree expression delivered from China in the 17th century, allowed the classification criteria of the trees described in the picture to be established and helped identify their types. As a result of the classification, there were 10 species and 50 trees in the Donhwamun Gate area of . Second, it was possible to measure the real size of the trees described in the picture through the elevated drawing scale of . The height of the trees ranged from a minimum of 4.37 m to a maximum of 22.37 m. According to the measurement results, compared to the old trees currently living in Changdeokgung Palace, the trees described in the picture were found to be produced in almost actual size without exaggeration. Thus, the measured height of the trees turned out to be appropriate as baseline data for reproduction of the vegetation landscape. Third, through the Rubber Sheeting Transformation of , it was possible to make a ground plan for the planting of on the current digital topographic map. In particular, as the transformed area of was departmentalized and control points were added, the precision of transformation improved. It was possible to grasp the changed position of planting as well as the change in planting density through a ground plan of planting of . Lastly, it was possible to produce a three-dimensional vegetation landscape model by using the information of the shape of the trees and the ground plan for the planting of . Based on the three-dimensional model, it was easy to examine the characteristics of the three-dimensional view of the current vegetation via the view axis, skyline, and openness to and cover from the adjacent regions at the level of the eyes. This study is differentiated from others in that it verified the realism of and suggested the possibility of ascertaining the original form of the vegetation landscape described in the painting.

A Study on the Influence of the Water System on the Location and Spatial Structure of Hongju-seong (수체계가 홍주성의 입지와 공간구조 변천과정에 미친 영향)

  • Lee, Kyung-Chan;Kang, In-Ae
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.38 no.4
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    • pp.12-24
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    • 2020
  • The purpose of this study is to analyze the influence of the water system on the location, spatial structure, and construction method of Hongju-eupseong, centering on Hongjumok-eupchi. During the Joseon Dynasty, the water system in Hongjumok-eupchi is composed of artificially constructed Seong-an Runnel and ponds based on a branch-shaped natural waterways flowing from south to north and west to east. Compiling the results of various literature records, excavations and analysis of map data, it can be seen that the water system has an important influence on the construction of Hongju-seong. Firstly, Hongju-seong from the Goryeo Dynasty to the late Joseon Dynasty is located using a circular shape of topographical structure and a small erosion basin formed on the inner side of the Hongseongcheon and Wolgyecheon streams without significant change in location. In particular, Wolgyecheon and Hongseongcheon are natural moats, which are harmonized with Sohyangcheon and riverside topographical structures, affecting the location and construction method of Hongju-seong, water related facilities, and the spatial structure of eupseong. It is understood that location characteristic of Hongju-seong reflects the urban location structure harmonized with waterways in ancient China and Korea. Secondly in harmony with the water system and topographic structure of Hongju-seong, it is an important factor in deciding the land use of the town, the arrangement of the town hall facilities and inducing various non-subsidiary measures such as the establishment of embankment forest with a secret function and the closure of the south gate. In addition, artificial drainage facilities such as Seongan runnel and ponds are being actively introduced from early on to protect the walls or towns from flooding of Wolgyecheon. Especially there were typical methods for protecting the walls from water damage such as the Joseon Dynasty stone castle structure that was integrated with saturn(soil wall) in the Goryeo Dynasty, retreating wall in the northern gate area in the late Joseon Dynasty, and the method of constructing wall using korean tile and stone floors between reinforced soil layers in the western and northern wall.

Studies on Changes in the Hydrography and Circulation of the Deep East Sea (Japan Sea) in a Changing Climate: Status and Prospectus (기후변화에 따른 동해 심층 해수의 물리적 특성 및 순환 변화 연구 : 현황과 전망)

  • HOJUN LEE;SUNGHYUN NAM
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.28 no.1
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    • pp.1-18
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    • 2023
  • The East Sea, one of the regions where the most rapid warming is occurring, is known to have important implications for the response of the ocean to future climate changes because it not only reacts sensitively to climate change but also has a much shorter turnover time (hundreds of years) than the ocean (thousands of years). However, the processes underlying changes in seawater characteristics at the sea's deep and abyssal layers, and meridional overturning circulation have recently been examined only after international cooperative observation programs for the entire sea allowed in-situ data in a necessary resolution and accuracy along with recent improvement in numerical modeling. In this review, previous studies on the physical characteristics of seawater at deeper parts of the East Sea, and meridional overturning circulation are summarized to identify any remaining issues. The seawater below a depth of several hundreds of meters in the East Sea has been identified as the Japan Sea Proper Water (East Sea Proper Water) due to its homogeneous physical properties of a water temperature below 1℃ and practical salinity values ranging from 34.0 to 34.1. However, vertically high-resolution salinity and dissolved oxygen observations since the 1990s enabled us to separate the water into at least three different water masses (central water, CW; deep water, DW; bottom water, BW). Recent studies have shown that the physical characteristics and boundaries between the three water masses are not constant over time, but have significantly varied over the last few decades in association with time-varying water formation processes, such as convection processes (deep slope convection and open-ocean deep convection) that are linked to the re-circulation of the Tsushima Warm Current, ocean-atmosphere heat and freshwater exchanges, and sea-ice formation in the northern part of the East Sea. The CW, DW, and BW were found to be transported horizontally from the Japan Basin to the Ulleung Basin, from the Ulleung Basin to the Yamato Basin, and from the Yamato Basin to the Japan Basin, respectively, rotating counterclockwise with a shallow depth on the right of its path (consistent with the bottom topographic control of fluid in a rotating Earth). This horizontal deep circulation is a part of the sea's meridional overturning circulation that has undergone changes in the path and intensity. Yet, the linkages between upper and deeper circulation and between the horizontal and meridional overturning circulation are not well understood. Through this review, the remaining issues to be addressed in the future were identified. These issues included a connection between the changing properties of CW, DW, and BW, and their horizontal and overturning circulations; the linkage of deep and abyssal circulations to the upper circulation, including upper water transport from and into the Western Pacific Ocean; and processes underlying the temporal variability in the path and intensity of CW, DW, and BW.

The Accuracy Evaluation of Digital Elevation Models for Forest Areas Produced Under Different Filtering Conditions of Airborne LiDAR Raw Data (항공 LiDAR 원자료 필터링 조건에 따른 산림지역 수치표고모형 정확도 평가)

  • Cho, Seungwan;Choi, Hyung Tae;Park, Joowon
    • Journal of agriculture & life science
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    • v.50 no.3
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    • pp.1-11
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    • 2016
  • With increasing interest, there have been studies on LiDAR(Light Detection And Ranging)-based DEM(Digital Elevation Model) to acquire three dimensional topographic information. For producing LiDAR DEM with better accuracy, Filtering process is crucial, where only surface reflected LiDAR points are left to construct DEM while non-surface reflected LiDAR points need to be removed from the raw LiDAR data. In particular, the changes of input values for filtering algorithm-constructing parameters are supposed to produce different products. Therefore, this study is aimed to contribute to better understanding the effects of the changes of the levels of GroundFilter Algrothm's Mean parameter(GFmn) embedded in FUSION software on the accuracy of the LiDAR DEM products, using LiDAR data collected for Hwacheon, Yangju, Gyeongsan and Jangheung watershed experimental area. The effect of GFmn level changes on the products' accuracy is estimated by measuring and comparing the residuals between the elevations at the same locations of a field and different GFmn level-produced LiDAR DEM sample points. In order to test whether there are any differences among the five GFmn levels; 1, 3, 5, 7 and 9, One-way ANOVA is conducted. In result of One-way ANOVA test, it is found that the change in GFmn level significantly affects the accuracy (F-value: 4.915, p<0.01). After finding significance of the GFmn level effect, Tukey HSD test is also conducted as a Post hoc test for grouping levels by the significant differences. In result, GFmn levels are divided into two subsets ('7, 5, 9, 3' vs. '1'). From the observation of the residuals of each individual level, it is possible to say that LiDAR DEM is generated most accurately when GFmn is given as 7. Through this study, the most desirable parameter value can be suggested to produce filtered LiDAR DEM data which can provide the most accurate elevation information.

Detection of Wildfire Burned Areas in California Using Deep Learning and Landsat 8 Images (딥러닝과 Landsat 8 영상을 이용한 캘리포니아 산불 피해지 탐지)

  • Youngmin Seo;Youjeong Youn;Seoyeon Kim;Jonggu Kang;Yemin Jeong;Soyeon Choi;Yungyo Im;Yangwon Lee
    • Korean Journal of Remote Sensing
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    • v.39 no.6_1
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    • pp.1413-1425
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    • 2023
  • The increasing frequency of wildfires due to climate change is causing extreme loss of life and property. They cause loss of vegetation and affect ecosystem changes depending on their intensity and occurrence. Ecosystem changes, in turn, affect wildfire occurrence, causing secondary damage. Thus, accurate estimation of the areas affected by wildfires is fundamental. Satellite remote sensing is used for forest fire detection because it can rapidly acquire topographic and meteorological information about the affected area after forest fires. In addition, deep learning algorithms such as convolutional neural networks (CNN) and transformer models show high performance for more accurate monitoring of fire-burnt regions. To date, the application of deep learning models has been limited, and there is a scarcity of reports providing quantitative performance evaluations for practical field utilization. Hence, this study emphasizes a comparative analysis, exploring performance enhancements achieved through both model selection and data design. This study examined deep learning models for detecting wildfire-damaged areas using Landsat 8 satellite images in California. Also, we conducted a comprehensive comparison and analysis of the detection performance of multiple models, such as U-Net and High-Resolution Network-Object Contextual Representation (HRNet-OCR). Wildfire-related spectral indices such as normalized difference vegetation index (NDVI) and normalized burn ratio (NBR) were used as input channels for the deep learning models to reflect the degree of vegetation cover and surface moisture content. As a result, the mean intersection over union (mIoU) was 0.831 for U-Net and 0.848 for HRNet-OCR, showing high segmentation performance. The inclusion of spectral indices alongside the base wavelength bands resulted in increased metric values for all combinations, affirming that the augmentation of input data with spectral indices contributes to the refinement of pixels. This study can be applied to other satellite images to build a recovery strategy for fire-burnt areas.