• Title/Summary/Keyword: time geography

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Landform Classification using Geomorphons (지형패턴(Geomorphons)을 이용한 새로운 지형분류방법)

  • KIM, Dong-Eun;SEONG, Yeong Bae;SOHN, Hak Gi;CHOI, Kwang Hee
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.4
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    • pp.139-155
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    • 2012
  • Most of previous landform classification methods using DEM compares the values between the center of the cell and the surrounding cells, which in turn, greatly depends on analysis scale. To overcome the problem of scale-dependency, a new classification scheme is developed, which is called "Geomorphons". Unlike the traditional approaches using DEM, Geomorphons is the way which compares the level with other cells against the criteria cell. As a pilot study, we classify the landforms of Pyeongchang-Gun in Korea. Then, we compare the result with the other methods such as Topographic Position Index. Through the systematic analysis, we obtain the following findings. First, Geomorphons can reduce the time for the classification of landforms because of using unsupervised classification. Second, Geomorphons is little dependent on change in the scale, which can provide a pilot tool for reconnaissance study for covering large area.

Analysis of Sedimentary Environment and Micro-Landform Changes Afterthe Construction of Artificial Structuresin the Tidal Flat of Anmyeondo Gagyeongju, Western Coast of Korea (인공구조물 건설 후 안면도 가경주 간석지의 퇴적환경 및 미지형변화 분석)

  • JANG, Dong-Ho;Ryu, Ju-Hyun
    • Journal of The Geomorphological Association of Korea
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    • v.25 no.1
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    • pp.31-45
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    • 2018
  • This study investigated the characteristics of sedimentary environment changes across a tidal flat in Gagyeongju of Anmyeondo Island. We performed a spatio-temporal analysis on the grain sizes composition of sediments and micro-landform changes during the winter from 2013 to 2016. The results showed that erosion was a dominant processthroughout the study flat, reducing the surface elevation even by 1 m around the upper sand flat. As a consequence, headlands have formed in the entire region of Gagyeongju village. In addition, erosion quickly progressed along the low-lying subtidal zone and tide way and, in contrast, sedimentation progressed in the mid-elevation tidal flat. We posit that a jetty, which had been constructed as a pier facility on the eastern part of the study area, interfered with the flow of tidal current, thereby enhancing these erosional processes. This is because such interference can block the supply of fine-textured sediments from the nearby Cheonsu Bay and therefore reduce surface elevation. According to the surface sediment analysis, the sediments were categorized into 7 sedimentary facies, and generally displayed a high ratio of silt and clay. The result of time-series analysis (2012-2013) showed that the sediments on the tidal flat became fine-grained, and that sorting became worse. However, the sediments on the subtidal zone, embayment and along inside of the jetty tended to be coarse-grained. In conclusion, the tidal flat microlandform change in the study area was caused by a disruption in the seawater circulation due to the jittery construction within the tidal flat, which had a direct effect on erosional and sedimentary environment processes.

Extracting the Distribution Potential Area of Debris Landform Using a Fuzzy Set Model (퍼지집합 모델을 이용한 암설지형 분포 가능지 추출 연구)

  • Wi, Nun-Sol;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.24 no.1
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    • pp.77-91
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    • 2017
  • Many debris landforms in the mountains of Korea have formed in the periglacial environment during the last glacial stage when the generation of sediments was active. Because these landforms are generally located on steep slopes and mostly covered by vegetation, however, it is difficult to observe and access them through field investigation. A scientific method is required to reduce the survey range before performing field investigation and to save time and cost. For this purpose, the use of remote sensing and GIS technologies is essential. This study has extracted the potential area of debris landform formation using a fuzzy set model as a mathematical data integration method. The first step was to obtain information about the location of debris landforms and their related factors. This information was verified through field observation and then used to build a database. In the second step, we conducted the fuzzy set modeling to generate a map, which classified the study area based on the possibility of debris formation. We then applied a cross-validation technique in order to evaluate the map. For a quantitative analysis, the calculated potential rate of debris formation was evaluated by plotting SRC(Success Rate Curve) and calculating AUC(Area Under the Curve). The prediction accuracy of the model was found to be 83.1%. We posit that the model is accurate and reliable enough to contribute to efficient field investigation and debris landform management.

The study on utilization of Hyangyak in 「Single-medicine prescription treatment of domestic herbs」 of 『Kwangjebikeup』 : Focusing on Ginseng (『광제비급』의 「향약단방치험」에 나타난 향약활용법에 대한 연구 - 인삼을 중심으로)

  • Kang, Yun Mi;Kim, Yun Kyung;Ahn, Sang Woo
    • The Korea Journal of Herbology
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    • v.29 no.3
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    • pp.1-10
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    • 2014
  • Objectives : In this study, we investigated Hyangyak in "Single-medicine prescription treatment of domestic herbs" of "Kwangjebikeup" and then conducted further studies focusing on ginseng as it is written in "Single-medicine prescription treatment of domestic herbs". Methods : Through a study of classical literature on Hyangyak and ginseng, information regarding the two was gathered and analyzed, with respect to both time and region. Results : All of the herbs in "Single-medicine prescription treatment of domestic herbs", the 4th volume of "Kwangjebikeup", are domestic herbs. Ginseng was a part of the flora of the Korean Peninsula from long ago and ginseng was cultivated from most of the peninsula. We confirmed cultivation of ginseng in Sungcheon, Pyungan-do and most areas of Hamgyeong-do through geography books such as "Geography Monograph of King Sejong". Because the natural environmental condition of the Korean Peninsula was conducive to growing wild ginseng, it was possible to cultivate ginseng. In the late Chosun period, cultivated ginseng was so prevalent that people would have been able to collect and use ginseng without great difficulty. In "Kwangjebikeup", ginseng shows superior efficacy in terms of first-aid. "Kwangjebikeup" contains practical herbal medicines that were based on obtainable ingredients. Conclusions : The purpose of publication of this book was to make medical knowledge available to general public in an easy-to-understand form. And through added clinical experiences of the author, we know that "Kwangjebikeup" played a role in settlement and spreading of foreign knowledge to civilians.

The short-term morphological changes of the beach and dune using by terrestrial LIDAR (지상 라이다를 이용한 단기간 해빈과 해안사구의 지형변화 연구)

  • Shin, Dae Seob;Seo, Jong Cheol
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.4
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    • pp.283-296
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    • 2011
  • The aim of this study is to analyze the short-term changes of beach and dune morphology at Hwajin beach, Korea using by terrestrial LIDAR. Based on ArcInfo as point cloud obtained through precise analyzing studying area twice (1st : Sep 1. 2010, 2nd : Oct 2nd. 2010) by terrestrial LIDAR, alteration of beach and dune was analyzed at DEM, of which cell size is about 10cm. Consequently, during the studying period, coastlines at studying area moved backward and reduced the area of coastal zone. In a section change, the north beach moved backward with more eroded beach face and the middle section of south beach moved forward with more deposited beach face. Considering all the section changes of beach at studying area, beach section during the 1st measurement period can be defined as a summer profile, and it can be explained that the temporary storm profile was formed by the strong wave created during studying period. As a result of analyzing the alteration of beach area by terrestrial LIDAR, alteration of narrow area was able to be analyzed in detail by class of 'centimeter' and the time was able to be shortened.

Landslide Risk Assessment of Cropland and Man-made Infrastructures using Bayesian Predictive Model (베이지안 예측모델을 활용한 농업 및 인공 인프라의 산사태 재해 위험 평가)

  • Al, Mamun;Jang, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.27 no.3
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    • pp.87-103
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    • 2020
  • The purpose of this study is to evaluate the risk of cropland and man-made infrastructures in a landslide-prone area using a GIS-based method. To achieve this goal, a landslide inventory map was prepared based on aerial photograph analysis as well as field observations. A total of 550 landslides have been counted in the entire study area. For model analysis and validation, extracted landslides were randomly selected and divided into two groups. The landslide causative factors such as slope, aspect, curvature, topographic wetness index, elevation, forest type, forest crown density, geology, land-use, soil drainage, and soil texture were used in the analysis. Moreover, to identify the correlation between landslides and causative factors, pixels were divided into several classes and frequency ratio was also extracted. A landslide susceptibility map was constructed using a bayesian predictive model (BPM) based on the entire events. In the cross validation process, the landslide susceptibility map as well as observation data were plotted with a receiver operating characteristic (ROC) curve then the area under the curve (AUC) was calculated and tried to extract a success rate curve. The results showed that, the BPM produced 85.8% accuracy. We believed that the model was acceptable for the landslide susceptibility analysis of the study area. In addition, for risk assessment, monetary value (local) and vulnerability scale were added for each social thematic data layers, which were then converted into US dollar considering landslide occurrence time. Moreover, the total number of the study area pixels and predictive landslide affected pixels were considered for making a probability table. Matching with the affected number, 5,000 landslide pixels were assumed to run for final calculation. Based on the result, cropland showed the estimated total risk as US $ 35.4 million and man-made infrastructure risk amounted to US $ 39.3 million.

A Study on the Spatial Distribution and Diffusion of Rice-paddy Weeding Songs Using the Geomorphic Elements in Jeolla-do: A Case of Arishigona, Sanaji and Bang-gae (지형요소를 활용한 전라도 논매기소리의 공간분포와 전파에 관한 연구: 아리시고나 류, 산아지 곡, 방게 류를 사례로)

  • Yoon, Hye-Yeon;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.28 no.2
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    • pp.71-85
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    • 2021
  • In this study, the effect on the spatial distribution and diffusion of Arishigona, Sanaji and Bang-gae appearing in Jeolla-do was analyzed using geomorphic elements. Based on result, the AriShigona is distributed in the western plains of the Yeongsan River basin and around from the Noryeong mountain range to Mudeung mountain range, the Sanaji is mainly diffused in the middle and upper parts of the Seomjin River and the lower parts of the Mangyeong River, Dongjin River and the Boseong River basin, and the Bang-gae is found to be distributed in the Seomjin River and the upper part of the Yeongsan River basin. Although the cultural centers of these Rice-paddy Weeding Songs are different but they appear to have a similar distribution pattern in Jeolla-do. This is used as a diffusion path of cultural elements by crossing lineaments in various directions and serving bridge role at the same time. However, in the region where the lineaments do not intersect, the continuity of Rice-paddy Weeding Songs are relatively low, which are considered to be reflected in the spatial distribution and propagation of the sound due to the influence of the drain network rather than the lineament. The results of this study can provide basic data for spatial distribution of Rice-paddy Weeding Songs, and regionality and cultural division by diffusion characteristics.

A Study on the Landscape Change in Nakdong River Delta The Case of Myeongjidong (낙동강 삼각주의 경관변화에 관한 연구 -명지동을 사례로-)

  • Heo, Minseok;SON, ILL;Tak, Hanmyeong
    • Journal of the Korean Geographical Society
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    • v.51 no.4
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    • pp.491-508
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    • 2016
  • This study has taken the Myeongjidong island, which has experienced spatial change due to various reasons ranging from the Japanese colonial era until today, as an instance in order to comprehend macroscopic spatial change of the Nakdonggang Delta and the adaptation process of the locals in a microscopic point of view. Spatial change of the Myeongjidong has been confirmed by collecting maps such as the atlas of late period of Chosun published in 1910, topographic map, regional geography, city records, and by applying coordinates with geographic reference function of GIS program, then checking for time sequential space change of individual regions. Space change driven by the Japanese government-general of Korea, Gimhae Irrigation Association, and by national policy or planning brought about environmental and humanistic changes unlike ever before, and land usage, housing and industry of the region and the locals experienced various adaptation processes. Such processes were compiled through collection and comparison of literature, and supplementation from interview of the locals during field study. As for the research region, it ranged from the construction of Nakdonggang bank and Myeongji seawall of 1935, agricultural rural landscape formed after the area expansion project by Gimhae Irrigation Association in 1940, to landscape that are becoming mercantile and urban due to the developmental plans of national and local governments.

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The Change of the Depositional Environment on Dodaecheon River Basin during the Middle Holocene (Holocene 中期에 있어서 道垈川流域의 堆積 環境 變化)

  • Hwang, Sang-Ill;Yoon, Soon-Ock;Jo, Wha-Ryong
    • Journal of the Korean Geographical Society
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    • v.32 no.4
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    • pp.403-420
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    • 1997
  • Dodaecheon is a small river flowing into Asan Bay which is located in the middle part of the West Coast of the Korean Penninsula. We have investigated the change of depositional environment in Dodaecheon river basin during the middle Holocene. In the course of the research, the methods such as boring, radiocarbon dating, diatom and pollen analysis were employed. The Holocene deposits of the studied area are consisted of peat and gray silt layers, and contain many plooen and diatom fossils. Based on the results of diatom and pollen analysis, we conclude that the gray silt layers were sedimented owing to the transgression in the middle Holocene, and the peat layers by the regression or stabilzation of the sea level. The shoreline in the Post Glacial Age reached to the rivemouth of Dodaecheon at ca. 7,000 years before present(y. BP) and at that time the high tide sea-level(mean high water level of spring tide) rose to ca. 3m above present mean sea-level(m.a.s.l.). Since then to ca. 6,000y. BP, the high tide sea-level arrived to ca. 5m above present mean sea level further repeating minor transgressions and regressions. The peat layers of the coastal lowland of the West Coast were formed by the sea level fluctuations from 7,000 y. BP to 3,000 y. BP, and they were distributed 2 to 6 meters higher than the mean sea level of the present day. Most of them sedimented due to the high tide level are older and higher than those of the East Coast which were formed at the swale in the low tidal range environment.

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A Study on Public Rental Housing for Young Generation Utilizing an Alternative Investment of National Pension Fund: Using Apartment Trading Data on Seoul Metropolitan Area from 2011 to 2016 (국민연금기금의 대체투자를 통한 청년층 공공임대주택 공급 후보지 분석: 2011-2016년 수도권 아파트 거래 자료를 토대로)

  • Cho, SeongAh;Hong, Yeryun;Lee, Seongmin;Shin, Hyu-Seok
    • Journal of the Economic Geographical Society of Korea
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    • v.21 no.2
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    • pp.156-172
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    • 2018
  • Recently, Korea suffered serious social conflicts between generations due to population aging. Anxiety about depletion of the National Pension Fund is one of the social problem to young generation, because of the uncertainty that they will not able to receive the pension they paid. At the same time, due to the high housing rent in Seoul metropolitan area, the demand for housing welfare and supply of public rental housing for young generation was increased. There are some opinions about using National Pension Fund to supplying public rental houses in the society. In this research, we were concentrated on finding the suitable areas for the public rental house using National Pension Fund. First, verifying the validity of the investment using National Pension Fund for the public rental housing was done. And spatial statistical methods were applied to explore the suitable areas for the public rental housing in Seoul metro area. Finally, this study divided young people into three groups and analyzed ways to supply public rental housing for each group in proper areas by their demand. This research's ultimate goals are mitigating the conflicts between the generations and achieving both profitability and publicness of National Pension Fund.