• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.4
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• pp.139-151
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• 2017

The habitat preference of roe deers(Capreolus pygargus) in Jeju island, South Korea was analyzed by using their occurrence probability in MaxEnt model in this study. Totally 490 surveying data were gathered and 15 environmental variables were chosen for the model in which 6 variables out of 15 ones were filtered and finally removed because of there being higher correlation(over 0.7 in correlation coefficient). According to the modeling, roe deers were known to prefer the area ranging from 200 to 700 meter and over 1,500 meter in sea level, where there were not many dominant tree and/or dominant vegetation with low density so that understory vegetation can grow well with plentiful sunlight and can be used as a food of herbivore like roe deers. Otherwise, the region ranging from 700 to 1,500 meter was mostly covered with high density vegetation which cut off sunlight trying to penetrate through the dominant vegetation. It can cause a lower density of vegetation on surface, which can not attract to roe deers.

• Journal of Korea Water Resources Association
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• v.44 no.2
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• pp.157-167
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• 2011

A numerical model was developed to predict the stage-discharge curve and lateral distribution of unit discharge in open channels with nonuniform cross section or compound open-channels. The governing equation is the one-dimensional momentum equation based on assumptions of the steady and uniform flow conditions in the longitudinal direction and the uniform water surface elevation in a cross section. Vegetative drag force term was included in governing equation in order to reflect the effect of floodplain vegetation on the flow characteristics. Finite element method was applied to obtain the numerical solution of the governing equation. Stage-discharge curve and lateral distribution of unit discharge for a given water surface are calculated based on input data, such as the cross sectional geometry, Manning's roughness coefficient, vegetative information and longitudinal slope of channel bed. The developed model was verified by comparing the calculated results with the observed data and the results of Darby and Thorne's(1996) model and the nonlinear k-$\epsilon$ model. The verified model was applied to estimate the upstream boundary conditions in two-dimensional flow model. The numerical results using laterally distributed unit discharge were compared with those obtained using uniformly distributed unit discharge in two-dimensional flow model.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.6-7
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• 2021

Vegetation development in rivers is one of the important issues not only in academic fields such as geomorphology, ecology, hydraulics, etc., but also in river management practices. The problem of river vegetation is directly connected to the harmony of conflicting values of flood management and ecosystem conservation. In Korea, since the 2000s, the issue of river vegetation and land formation has been continuously raised under various conditions, such as the regulating rivers downstream of the dams, the small eutrophicated tributary rivers, and the floodplain sites for the four major river projects. In this background, this study proposes a method for classifying the distribution of vegetation in rivers based on remote sensing data, and presents the results of applying this to the Naeseong Stream. The Naeseong Stream is a representative example of the river landscape that has changed due to vegetation development from 2014 to the latest. The remote sensing data used in the study are images of Sentinel 1 and 2 satellites, which is operated by the European Aerospace Administration (ESA), and provided by Google Earth Engine. For the ground truth, manually classified dataset on the surface of the Naeseong Stream in 2016 were used, where the area is divided into eight types including water, sand and herbaceous and woody vegetation. The classification method used a random forest classification technique, one of the machine learning algorithms. 1,000 samples were extracted from 10 pre-selected polygon regions, each half of them were used as training and verification data. The accuracy based on the verification data was found to be 82~85%. The model established through training was also applied to images from 2016 to 2020, and the process of changes in vegetation zones according to the year was presented. The technical limitations and improvement measures of this paper were considered. By providing quantitative information of the vegetation distribution, this technique is expected to be useful in practical management of vegetation such as thinning and rejuvenation of river vegetation as well as technical fields such as flood level calculation and flow-vegetation coupled modeling in rivers.

• Journal of Ecology and Environment
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• v.41 no.3
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• pp.85-92
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• 2017

Unmanned aerial vehicles (UAVs) are a new and yet constantly developing part of forest inventory studies and vegetation-monitoring fields. Covering large areas, their extensive usage has saved time and money for researchers and conservationists to survey vegetation for various data analyses. Post-processing imaging software has improved the effectiveness of UAVs further by providing 3D models for accurate visualization of the data. We focus on determining the coniferous tree coverage to show the current advantages and disadvantages of the orthorectified 2D and 3D models obtained from the image photogrammetry software, Pix4Dmapper Pro-Non-Commercial. We also examine the methodology used for mapping the study site, additionally investigating the spread of coniferous trees. The collected images were transformed into 2D black and white binary pixel images to calculate the coverage area of coniferous trees in the study site using MATLAB. The research was able to conclude that the 3D model was effective in perceiving the tree composition in the designated site, while the orthorectified 2D map is appropriate for the clear differentiation of coniferous and deciduous trees. In its conclusion, the paper will also be able to show how UAVs could be improved for future usability.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.4
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• pp.72-81
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• 2001

This study is aimed to review the previous research accomplishments with analysis of problems and to suggest the counter plan for the watershed management and the ongoing research strategy. Phytoremediation provides a cost-effective techniques having a merit of low investment and maintenance cost. It could be one of the best techniques, which is an alternative plan to overcome economical situation and lack of experts in our country. In forest watershed affected by waste water and heavy metal pollutants should be controlled by vegetative remediation system, but the disposal techniques of harvested plant materials should be developed. Also, high degree areas of natural vegetation as a key model to recover the vegetation should be well conserved. It is important to restore forest continuity between upper stream and lower stream basin with the restoration of damaged in forest watershed. It is established to integrated protection system for land use and management plan and to natural environment evaluation methods affected by projects such as erosion control and developments in stream and forest. In addition, I suggest the continuous environmental monitoring system to treat the pollutions concerned.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.162-165
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• 2004

The authors' previous study found an interannual covariability between actual evapotranspiration (ET) and the Normalized Difference Vegetation Index (NDVI) over northern Asia. This result suggested that vegetation controls interannual variation in ET. In this prior study, NDVI data from the Pathfinder AVHRR Land (PAL) dataset were analyzed. However, studies of NDVI interannual change are subject to uncertainty, because NDVI data often contain errors associated with sensor- and atmosphere-related effects. This study is aimed toward reducing this uncertainty by employing NDVI dataset, from the Global Inventory Monitoring and Modeling Studies (GIMMS) group, in addition to PAL. The analysis was carried out for the northern Asia region from 1982 to 2000. 19-year interannual change in PAL-NDVI and GIMMS-NDVI were both compared with interannual change in model-assimilated ET. Although the correlation coefficient between GIMMS-NDVI and ET is slightly less than for PAL-NDVI and ET, for both NDVI datasets the annual maximum correlation with ET occurs in June, which is near the central period of the growing season. A significant positive correlation between GIMMS-NDVI and ET was observed over most of the vegetated land area in June as well as PAL-NDVI and ET. These results reinforce the authors' prior research that indicates the control of interannual change in ET is dominated by interannual change in vegetation activity.

• Journal of Environmental Science International
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• v.20 no.11
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• pp.1457-1464
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• 2011

In this study, the method of estimating hydrologic information (water depth, submerged period etc.) on the proper selection of construction point and scale as well as vegetation type suggested for the design of natural riparian rehabilitation structure. Long-term comprehensive watershed model SWAT-K(Korea) was applied to this purpose. Flow duration analysis was conducted to analyze the hydrologic characteristics of Pyungchang watershed at which the 'bangtul' construction method was tested. For this purpose 20 years (1989-2008) rainfall runoff analysis was carried out. Based on the simulated daily streamflow data, flow duration curve was made to analyze the flow characteristics, and the water depth hydrograph was made to analyze the water depth distribution at the cross section. Finally, the information for the selection of proper vegetation according to the submerged period is suggested.

• Journal of Environmental Impact Assessment
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• v.19 no.3
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• pp.347-356
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• 2010

Forests are being seriously fragmented as a result of land development. Land development with disregard to its subsequent environmental impacts is a primary threat to biodiversity by incurring massive habitat losses and changes in structure and composition of forests. The purpose of this study was to develop the impact assessment model for quantitative distance or degree of disturbance by land developments. This study conducted a survey about structure and composition of forest species to determine degree of impact from land development. The edge effect of forest fragmentation on the number of bird species, population size, and bird diversity was obvious. In particular, the bird diversity sharply declines around the forest edge where intensive land development projects take place. To assess the disturbance of forest species, the factors selected were the bird diversity and the rate of edge species. The impact assessment model about bird diversity was explained by type of forest fragmentation and type of vegetation ($R^2$=0.23, p<0.005). The other model about edge species explained by a distance, type of forest fragmentation, type of vegetation, and width of road ($R^2$=0.34, p<0.001). In order to test the applicability of the model developed in this study, the models was applied to the Samsong housing development in Goyang-si, Gyunggi-do. The impacts of land development on the bird species were reasonably quantified to suggest effective mitigation measure. The impact assessment model developed in this study is useful to assess the magnitude of disturbance of bird species. Particularly, the model could be applied to the current Environmental Impact Assessment practices to predict and quantify the impacts of land developments projects on forest bird species.

• Journal of Environmental Impact Assessment
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• v.2 no.1
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• pp.39-55
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• 1993

The importance of urban and regional natural park increases because of the needs for preserving the natural resources and providing with natural recreation space in nature. This planning of natural park management should be established based on the research of the various natural resources in the park. But for the lack of effective data synthesizing methods and concepts, only some restricted factors for zoning plan are considered even though GIS computer system for large complex simulation is used. Therefore, in this study three ecological zoning models such as Basic Factor Model (BFM), Visual Landscape Model (VLM) and Comprehensive Ecological Model (CEM) are proposed and applied to Byounsan Peninsula Nature Park(BPNP) for comparison with the current natural park zoning. The BFM has three components -elevation, slope and vegetation. The VLM has applied with six components -elevation, slope, vegetation, road type, and the visual distance. Finally the CEM's modelling factors have included all of BFM, VLM components are added with the land use type, nature and historic resource factors. The zoning concept of BPNP was based on "Minimization" focused on the specific factors. But introduced modelling concept is "Optimization" based on the total ecological environment. So the result of the modelling has larger area for preservation and development zoning compared with the current zoning whose characteristics are ambiguous which allows the environmental destruction. The future study issues will be the determination of the weighting factor, component reconsideration based on the ground truth data and the agriculture residential area zoning.

• Korean Journal of Environment and Ecology
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• v.21 no.5
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• pp.400-414
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• 2007

This study has analyzed the vegetation structure to suggest a vegetation ecological restoration model by using the case of the afforestation for erosion control area with Pinus koreaiensis and Betula platyphylla, etc., on the hills of the Young-in mountains after its great fire in 2000. Of the area having a dimension of $1,152,404.3m^2$ selected as a survey site for the existing vegetation, the forest fire area accounted for 69.2% among which, brushwoods accounted the most for 24.67%. As a result of analysis of the 27 surveyed unit plots[unit dimension: $100m^2$] set up in consideration of the existing vegetation pattern and damaged state from the forest fire, the surveyed area was classified into 10 communities. Shrub layer's vegetation was found to be dominant in forest fire areas and the surveyed sites were classified into 5 plant communities, i.e. P. koraiensis community, Quercus variabilis community, P. thunbergii community, Q. serrata community, B. platyphylla community in forest fire areas, while non-forest fire areas were classified into 5 plant communities, such as P. densiflora community, Q. acutissima community, Q. serrata community, Q. mongolica-Q. serrata community, B. platyphylla community. Species diversity of forest fire areas was $0.3679{\sim}0.5907$ and that of non-forest fire areas was $0.5728{\sim}0.8865$. In addition, the number of the species in the forest fire areas was $5{\sim}8$ and that of non-forest areas was $8{\sim}12$; however, the population of forest fire areas$(156{\sim}456)$ was higher than that of non-forest fire areas$(61{\sim}227)$. In the analysis of growth density per layer$[of\;100m^2]$, there appeared $1{\sim}8$ trees of Q. mongolica and $3{\sim}5$ trees of Q. serrata in the upper layer species; $2{\sim}4$ trees of Q. serrata and one tree of Q. mongolica in the canopy layer. As for the characteristics of soil, acidity of forest fire areas was pH 5.45 and that of non-forest fire was pH 5.25. By setting up the middle D.B.H range of Q. mongolica-Q. serrata community as the vegetation restoration model, planting species, planting density and planting models are suggested.