• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.1 s.116
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• pp.96-104
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• 2007

Currently, there is a lack of suitable prediction model and measurement data for vegetation loss. So in this paper, vegetation loss measurement has been performed for seven different tree-species, including dawn-redwood tree, plane tree, pine tree and hymalaya cedar in the frequency range of $1.0{\sim}6.0\;GHz$, for the two years, from 2005 to 2006 years. And then, extraction and revision for the proposed RET model input parameters in ITU-R P.833 has been performed. The key results of measurement and RET modeling has been presented in this paper. The results of this study have been adapted for ITU-R recommendation at the ITU-R meeting in 2005 and 2006.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.1
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• pp.96-112
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• 1998

This study aims to evaluate the potential of pro-environmental application(PEP) in streams conceptualized ecological conservation and recreational use to be in harmony with. The main content of research are to clarify the PEP, to establish the evaluation model, and to evaluate 3 streams(Dongchon, Seokhyunchon, Okchon) in Sunchon city. Researchers introduced 12 evaluation items(water quality, water quantity, vegetation-water area, vegetation conservation, streamscape, neighborhood landscape, stream width, optimum area, nearby landuse, facility in stream, distance from user, obstacle to acces) by 5 scales to evaluate the characteristics of natural and artificial factors in stream area and nearby area. Also to decide the weight of items, researchers surveyed the opinion of 22 landscape architects experienced stream-plan through delphi method. Lastly the pro-environmental potential on streams were calculated by the ecological potential and recreational potential indices to be standardized and indicidual sections in streams were divided 5 grades on the basis of PEP. The result of this study are as follows; 1) The evaluation model of PEP was constructed by 4 steps, such as the decision of weight, the measurement of scale, the calculation of potential indices, the gradation of individual sections in streams. 2) The ecological potential were highly influenced by natural factor such as water quality, vegetation conservation, vegetation-water area, but on the other hand the recreational potential were influenced by optimum area, distance from user, water quantity, obstacle to access. 3) The factors such as vegetation conservation, optimum area, nearby landuse, distance from user were function as discernment factors to evaluate relatively ecological and recreational potential. and water quality, water quantity, vegetation -water area, neighborhood landscape were acted as important items to decide PEP.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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• pp.65-77
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• 2015

The urban park has important functions as a habitat for wildlife as well as open space of rest and community for people. This study was carried out to find what factors of structure and vegetation of urban parks could affect forest bird species diversity in Cheonan city. The study surveyed bird and vegetation species in 26 urban parks, Cheonan city. A correlation analysis and multiple linear regressions were performed to test whether habitat structure and vegetation were the major correlate with species diversity. The results showed the Dujeong park was the most high bird species diversity (H' = 2.13), and the Dujeong-8 park (H' = 2.02) and the Cheongsa park (H' = 1.73) were considerably higher than the other urban parks. The variables that were strongly correlated with bird species diversity were park area, number of subtree species, canopy of shrub, number of shrub species, shape index, canopy of subtree, canopy of tree, and impervious surface ratio. The regression of bird species diversity against the environmental variables showed that 3 variables of park area, canopy of subtree, and canopy of tree were included in the best model. Model variable selection was broadly similar for the 5 optimal models. It means park area and multi-layer vegetation were the most consistent and significant predictor of bird species diversity, because urban parks were isolated by built-up areas. Especially the subtree coverage that provides shelter and food for forest birds was an important variable. Therefore, to make parks circular-shaped and abundant multi-layer vegetation, which could be a buffer to external disturbances and improve the quality of habitats, may be used to enhance species diversity in creation and management of urban parks.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.3
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• pp.73-85
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• 2002

The purpose of this study was to develop prediction models for plant species abundance by stream restoration. Generally the stream plant is affected by stream gemophology. So in this study, the relationship between the vegetation abundance and stream gemophology was developed by multiple regression analysis. The stream characteristics utilized in this study were longitudinal slope, transectional slope, micro-landforms through the longitudinal direction, riparian width and geometric mean diameter and biggest diameter of bed material, and cumulated coarse and fine sand weight portion. The Pyungchang River with mountainous watershed and the Kyungan stream and the Bokha stream in the agricultural region were selected and vegetation species abundance and stream characteristics were documented from the site at 2~3km intervals from the upper stream to the lower. The Models for predicting the vegetation abundance were developed by multiple regression analysis using SPSS statistics package. The linear relationship between the dependant(species abundance) and independant(stream characteristics) variables was tested by a graphical method. Longitudinal and transectional slope had a nonlinear relationship with species abundance. In the next step, the independance between the independant variables was tested and the correlation between independant and dependant variables was tested by the Pearson bivariate correlation test. The selected independant variables were transectional slope, riparian width, and cumulated fine sand weight portion. From the multiple regression analysis, the $R^2$for the Pyungchang river, Kyungan stream, Bokga stream were 0.651, 0.512 and 0.240 respectively. The natural stream configuration in the Pyungchang river had the best result and the lower $R^2$for Kyunan and Bokha stream were due to human impact which disturbed the natural ecosystem. The lowest $R^2$for the Bokha stream was due to the shifting sandy bed. If the stream bed is fugitive, the prediction model may not be valid. Using the multiple regression models, the vegetation abundance could be predicted with stream characteristics such as, transection slope, riaparian width, cumulated fine sand weigth portion, after stream restoration.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.6
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• pp.25-33
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• 2022

In this study, a monitoring method using high-resolution images acquired by unmanned aerial vehicles and deep learning algorithms was proposed for the management of the Sinduri coastal sand dunes. Class classification was done using U-net, a semantic division method. The classification target classified 3 types of sand dune vegetation into 4 classes, and the model was trained and tested with a total of 320 training images and 48 test images. Ignored label was applied to improve the performance of the model, and then evaluated by applying two loss functions, CE Loss and BCE Loss. As a result of the evaluation, when CE Loss was applied, the value of mIoU for each class was the highest, but it can be judged that the performance of BCE Loss is better considering the time efficiency consumed in learning. It is meaningful as a pilot application of unmanned aerial vehicles and deep learning as a method to monitor and manage sand dune vegetation. The possibility of using the deep learning image analysis technology to monitor sand dune vegetation has been confirmed, and it is expected that the proposed method can be used not only in sand dune vegetation but also in various fields such as forests and grasslands.

• Journal of Environmental Science International
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• v.28 no.2
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• pp.259-266
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• 2019

Two main sources of data, meteorological data and land surface characteristics, are essential to effectively run a distributed rainfall-runoff model. The specification and averaging of the land surface characteristics in a suitable way is crucial to obtaining accurate runoff output. Recent advances in remote sensing techniques are often being used to derive better representations of these land surface characteristics. Due to the mismatch in scale between digital land cover maps and numerical grid sizes, issues related to upscaling or downscaling occur regularly. A specific method is typically selected to average and represent the land surface characteristics. This paper examines the amount of flooding by applying the FLO-2D routing model, where vegetation heterogeneity is manipulated using the Manning's roughness coefficient. Three different upscaling methods, arithmetic, dominant, and aggregation, were tested. To investigate further, the rainfall-runoff model with FLO-2D was facilitated in Yongdam catchment and heavy rainfall events during wet season were selected. The results show aggregation method provides better results, in terms of the amount of peak flow and the relative time taken to achieve it. These rwsults suggest that the aggregation method, which is a reasonably realistic description of area-averaged vegetation nature and characteristics, is more likely to occur in reality.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.28-28
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• 2022

본 연구는 용담댐유역을 포함한 금강 유역 상류 지역을 대상으로 Sentinel-1 SAR (Synthetic Aperture Radar) 위성영상을 기반으로 한 토양수분 산정을 목적으로 하였다. Sentinel-1 영상은 2019년에 대해 12일 간격으로 수집하였고, 영상의 전처리는 SNAP (SentiNel Application Platform)을 활용하여 기하 보정, 방사 보정 및 Speckle 보정을 수행하여 VH (Vertical transmit-Horizontal receive) 및 VV (Vertical transmit-Vertical receive) 편파 후방산란계수로 변환하였다. 토양수분 산정에는 Water Cloud Model (WCM)이 활용되었으며, 모형의 식생 서술자(Vegetation descriptor)는 RVI (Radar Vegetation Index)와 NDVI (Normalized Difference Vegetation Index)를 활용하였다. RVI는 Sentinel-1 영상의 VH 및 VV 편파자료를 이용해 산정하였으며, NDVI는 동기간에 대해 10일 간격으로 수집된 Sentinel-2 MSI (MultiSpectral Instrument) 위성영상을 활용하여 산정하였다. WCM의 검정 및 보정은 한국수자원공사에서 제공하는 10 cm 깊이의 TDR (Time Domain Reflectometry) 센서에서 실측된 6개 지점의 토양수분 자료를 수집하여 수행하였으며, 매개변수의 최적화는 비선형 최소제곱(Non-linear least square) 및 PSO (Particle Swarm Optimization) 알고리즘을 활용하였다. WCM을 통해 산정된 토양수분은 피어슨 상관계수(Pearson's correlation coefficient)와 평균제곱근오차(Root mean square error)를 활용하여 검증을 수행할 예정이다.

• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.37-48
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• 2011

Recently, the social and environmental functions of nature river are important due to the increase of expectation for river restoration. So it should be considered the effect of vegetation affecting the conveyance capacity and hydraulic resistance. However, it has not yet proposed a objective standard and modeling method to estimate the effect of conveyance capacity according to vegetaion distribution in the watercourse such as water level or velocity. Therefore, this study simulates the variations of water level and velocity using 3-dimensional hydrodynamic model, EFDC, to consider a conveyance capacity in downstream of the Soyang Reservoir. The simulation results were validated using statistical index such as F-test and T-test. As results, the water level rises about 0.01 to 0.47m and velocity difference are about -0.95m/s to 0.23m/s.

• Journal of Mechanical Science and Technology
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• v.18 no.10
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• pp.1799-1808
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• 2004

Knowledge of airflow characteristics in nasal cavity is essential to understand the physiological and pathological aspects of nasal breathing. Several studies have utilized physical models of the healthy nasal cavity to investigate the relationship between nasal anatomy and airflow. Since the final goal of these works is their contribution to the diagnosisand treatment of nasal diseases, the next step on this topic is naturally studies for disordered nasal cavities. In this paper, as the first application, airflows in the normal and abnormal nasal cavities with adenoid vegetation are investigated experimentally by PIV, and comparisons of both cases are appreciated. Dense CT data and careful treatment of model surface under the ENT doctor's advice provide more sophisticatedcavity model. The CBC PIV algorithm with window offset is used for PIV flow analysis. Average and RMS distributions are obtained for inspirational and expirational nasal airflows. Airflow characteristics that are related with the abnormalities in nasal cavity are presented.

• Korean Journal of Environment and Ecology
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• v.11 no.3
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• pp.352-365
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• 1997

As a serials of researches for the restoration model of evergreen broad-leaved forests, the restoration strategies of the case study areas were proposed. Restoration type of vegetation were classified into an improvement type and a reconstruction type and a reconstruction type for Wando(Island). Improvement type of restoration was suggested for Mokdo(Island). Quercus acuta community, Q. salicina community, Neolitsea sericea community, Castanopsis cuspidata var. sieboldii community, Machilus thunbergii community, Cinnamomum japonicum community, etc. were suggested as a restoration goal of vegetation for Sando(Island). Machlus thunvergii community was suggested as a restoration goal of vegetation for Mokdo(Island). Also the species restoration olan of the Wando(Island) was prepared for Quercus salicina of Fagaceae and Ostrya japonica of Betulaceae those which the natural distribution and population size were very limited. There was no species which needed for species restoration urgently at Mokdo(Island).