• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.135-142
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• 2012

The map drawn on a scale of 1 to 50,000, modern Korea map drawn on a scale of 1 to 50,000 made by Japanese colonial era in 1910s, is the first topographical map using modern technical method. The map has been mainly used in human activities and geographic viewpoint, recently it is available on various field with recognizing high accuracy. It is especially expected that the map will provide us with lots of information on long-term change of topography in field of coastal area which is built on coastal structure. This study presents a method for analyzing before and after geographic change of coastal structure in independent drift sand system. The reference point to analyze long-term coastal geographic change was selected the map of 1910s.

• Journal of The Geomorphological Association of Korea
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• v.20 no.1
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• pp.75-83
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• 2013

Human-induced modifications in coastal area may cause strong geomorphic responses by disturbing sediment supply, transport and deposition regimes. Morever, engineering structure have been built to stabilize coastal change, these effort impact on other morphologic change. In case of coastal area, there are lack of sediment yield data. This study focus on the tendency of long-term shoreline change, estimate method od sediment discharge which is a major factor of coastal change and adduced to way for considering design load influenced to coastal road.

• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.1
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• pp.49-66
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• 2024

Extreme rainfall will become intense due to climate change, increasing inundation risk to agricultural land. Hydrological and hydraulic simulations for the entire watershed were conducted to analyze the impact of climate change. Rainfall data was collected based on past weather observation and SSP (Shared Socio-economic Pathway)5-8.5 climate change scenarios. Simulation for flood volume, reservoir operation, river level, and inundation of agricultural land was conducted through K-HAS (KRC Hydraulics & Hydrology Analysis System) and HEC-RAS (Hydrologic Engineering Center - River Analysis System). Various scenarios were selected, encompassing different periods of rainfall data, including the observed period (1973-2022), near-term future (2021-2050), mid-term future (2051-2080), and long-term future (2081-2100), in addition to probabilistic precipitation events with return periods of 20 years and 100 years. The inundation area of the Aho-Buin district was visualized through GIS (Geographic Information System) based on the results of the flooding analysis. The probabilistic precipitation of climate change scenarios was calculated higher than that of past observations, which affected the increase in reservoir inflow, river level, inundation time, and inundation area. The inundation area and inundation time were higher in the 100-year frequency. Inundation risk was high in the order of long-term future, near-term future, mid-term future, and observed period. It was also shown that the Aho and Buin districts were vulnerable to inundation. These results are expected to be used as fundamental data for assessing the risk of flooding for agricultural land and downstream watersheds under climate change, guiding drainage improvement projects, and making flood risk maps.

• Journal of Soil and Groundwater Environment
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• v.18 no.4
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• pp.40-49
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• 2013

In the beginning of $20^{th}$ century, the coal mining industry had an important role in Japan at which two-thirds of the coal product came from the Kitakyushu-Chikuho District (KCD). As a consequence of mining activities, land-use condition in this district showed notable changes. This paper presented a study of land-use changes in coal mining area by characterizing land-use pattern transition over the last 100 years. In order to carry out the rigorous analysis of land-use, a series of land-use maps over the last 100 years was developed using geographic information systems (GIS). The historic topographic map and another available old data were used to investigate the long-term changes of land-use associated with past mining within the GIS platform. The results showed that the utilization of a series of developed land-use maps successfully indicated the difference of land-use pattern in the KCD before and after the peak of mining activities. The general findings from land-use analysis described that forest and farm lands were lost and turned into abandoned sites in the last 100 years.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.1
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• pp.101-115
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• 2006

As coastal erosion is increasing sharply because of sudden changes in the natural environment and increases in artificial development, the problem of coastal erosion become an important issue, socially and economically. To building the data which needed to grasp the situation and find a solution, we need the monitoring system for long-term. In this study, we analyzed the coastal topography and land cover changes in the Haeundae Beach during 60 years. The Haeundae Beach is the most famous beach in the country and coastal erosion are going on. First, we analyzed the change of coastal topography by calculated the coastline and area of the beach using aerial photos during 60 years. We extracted the coastline by digitized on aerial photo and corrected the height of tide level using sounding and GPS survey data. And we computed the area of beach and analyzed the change of area during 60 years. Second, we analyzed the change of land cover using landcover map. We made the detailed landcover map by on-screen digitizing and estimated the soil loss for the area nearby Haeundae Beach. As a result, we could see that the coastline get nearer to land and the area of beach has been reduced in general. We think that interception of sand supply by the development is the artificial cause of coastal erosion. The result of this study would be useful in long-term coastal monitoring and to analyze the cause of coastal environment change. We expect that the result is available on the coastal information system.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.2
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• pp.1-10
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• 2007

The tendency of erosion and accretion of the coast has occurred by the wanton development of a shore so that establishing the plans of nature preservation and development according to shoreline change is in demand. In this study, six DGPS positioning are executed in the periodic interval of about 2 months to choose coastal area of Gangnung, Gangwon-do and the observation data which is post-processed about 50cm accuracies on the Gangnung regular service is compared with digital map in 1998 and digital chart in 2006. Comparing DGPS values with shoreline of digital map, we know that erosion has occurred locally around training dike placed in Gangmun harbor and in southern Namhangjin, many accretions has happened near the breakwater of Namhangjin region and partial accretion is occurring in the other area. Therefore DGPS which is an acquisition method suitable for GIS data input is in use to collect the horizontal data and it could be used effectively to measure the shoreline change of time series through the long-term continuous observation by the coastal development.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.4
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• pp.111-124
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• 2010

To monitor the environment of land surface change is considered as an important research field since those parameters are related with land use, climate change, meteorological study, agriculture modulation, surface energy balance, and surface environment system. For the change detection, many different methods have been presented for distributing more detailed information with various tools from ground based measurement to satellite multi-spectral sensor. Recently, using high resolution satellite data is considered the most efficient way to monitor extensive land environmental system especially for higher spatial and temporal resolution. In this study, we use two different spatial resolution satellites; the one is SPOT/VEGETATION with 1 km spatial resolution to detect coarse resolution of the area change and determine objective threshold. The other is Landsat satellite having high resolution to figure out detailed land environmental change. According to their spatial resolution, they show different observation characteristics such as repeat cycle, and the global coverage. By correlating two kinds of satellites, we can detect land surface change from mid resolution to high resolution. The K-mean clustering algorithm is applied to detect changed area with two different temporal images. When using solar spectral band, there are complicate surface reflectance scattering characteristics which make surface change detection difficult. That effect would be leading serious problems when interpreting surface characteristics. For example, in spite of constant their own surface reflectance value, it could be changed according to solar, and sensor relative observation location. To reduce those affects, in this study, long-term Normalized Difference Vegetation Index (NDVI) with solar spectral channels performed for atmospheric and bi-directional correction from SPOT/VEGETATION data are utilized to offer objective threshold value for detecting land surface change, since that NDVI has less sensitivity for solar geometry than solar channel. The surface change detection based on long-term NDVI shows improved results than when only using Landsat.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.75-77
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• 2003

The spatial distribution of snow cover area is a crucial input to models of hydrology and climate in alpine and other seasonally snow covered areas.The objective in our study is to develop a rapidly automatic and high accuracy snow cover mapping algorithm applicable for the Tibetan Plateau which is the most sensitive about climatic change. Monitoring regional snow extent reqires higher temoral frequency-moderate spatial resolution imagery.Our algorithm is based AVHRR and MODIS data and will provide long-term fraction snow cover area map.We present here a technique is based on the multiple endmembers approach and by taking advantages of current approaches, we developed a technique for automatic selection of local reference spectral endmembers.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.3
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• pp.13-21
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• 2004

The dissemination of commercial satellite images. which have the high spatial resolution such as aerial photos, are the active trend in remote sensing community because of the recent development in satellite and sensor technology. Such high resolution satellite images provide a unique tool for the monitoring of ongoing urban land use change. Especially KOMPSAT-1, which was launched at December 1999 and successfully operated up to now, provides repeatedly panchromatic images over Korean peninsula, which has the spatial resolution of 6.6m. Based upon this KOMPSAT-1 EOC image data we can try to analyze and assess the temporal urban land use change, which could not be done because lack of such data. The aim of this paper is to analyze and assess the spatial land use characteristics of Daejeon Metropolitan City based on KOMPSAT-1 EOC data. The land use map of year 2001 is generated through the modification of the year 2000 land use map, which is published by National Geographic Information Institute, using visual interpretation of KOMPSAT-1 EOC image which is acquired in year 2001. This study can be the start point of the time series analysis of the long term land use change monitoring mit KOMPSAT-1 EOC data.

• Journal of the Korean Association of Geographic Information Studies
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• v.6 no.1
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• pp.107-118
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• 2003

The purpose of this study is to assess the hydrological impact on a watershed from long-term land cover changes. Gyeongan-cheon watershed($558.2km^2$) was selected and WMS(watershed modeling system) HEC-1 model was adopted as an evaluation tool. To identify land cover changes, five Landsat images(1980/2/15, 1986/4/15, 1990/4/26, 1996/4/26, 2000/5/17) were selected and analyzed using maximum likelihood method. As a result, urban areas have increased by 5.6% and forest areas have decreased by 6.1% between 1980 and 2000. SCS curve number increased by 9.8. To determine model parameters and evaluate HEC-1 model, five storm events(1998/5/2, 1998/8/23, 1998/9/30, 1999/5/3, 2000/7/29) were used. The simulated stream flow agreed well with the observed one with relative errors ranging from 9% to 36%. For 254 mm daily rainfall of 30 years frequency, due to the increase of urban areas peak flow increased by $455m^3/sec$ and the time of peak flow reduced about four hours for 20 years land cover changes.