• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.122-131
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• 2010

This paper introduces the concept of a virtual ecosystem and reports the following three mathematical approaches that could be widely used to construct such an ecosystem, along with examples: (1) a molecular dynamics simulation approach for animal flocking behavior, (2) a stochastic lattice model approach for termite colony behavior, and (3) a rule-based cellular automata approach for biofilm growth. The ecosystem considered in this study consists of artificial organisms and their environment. Each organism in the ecosystem is an agent that interacts autonomously with the dynamic environment, including the other organisms within it. The three types of model were successful to account for each corresponding ecosystem. In order to accurately mimic a natural ecosystem, a virtual ecosystem needs to take many ecological variables into account. However, doing so is likely to introduce excess complexity and nonlinearity in the analysis of the virtual ecosystem's dynamics. Nonetheless, the development of a virtual ecosystem is important, because it can provide possible explanations for various phenomena such as environmental disturbances and disasters, and can also give insights into ecological functions from an individual to a community level from a synthetic viewpoint. As an example of how lower and higher levels in an ecosystem can be connected, this paper also briefly discusses the application of the second model to the simulation of a termite ecosystem and the influence of climate change on the termite ecosystem.

• Korean Journal of Heritage: History & Science
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• v.42 no.1
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• pp.188-209
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• 2009

Dangsan forests had been established by local residents several hundred years ago. They were disturbed in various ways, but still remain in many villages where dangsan festivals are held every year. Although the remaining Dangsan forests represent korean rural cultural landscapes, their characteristics still remain to be uncovered. The objectives of this study were to understand the three elements, Dangsan tree (Divine tree), shrine and stone tower, and to investigate the culture at inland areas and seashore areas relation to Dangsan forests. Twenty cases of Dangsan forests at inland areas and twenty at seashore areas were investigated. There were nine shrines and six stone towers found out of twenty inland Dangsan forests. Fifteen shrines were found out of twenty seashore Dangsan forests. Stone tower was not found at seashore areas. Fifteen events of dangsan festival were investigated. Dangsan festival appeared to have played an important role to preserve Dangsan forests. Based on the findings of this study, Dangsan forests are, as landscape elements at inland and seashore areas, proved to have a potential for the improvement of cultural and natural landscapes in the country.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.2
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• pp.87-96
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• 2023

Recently, research on predicting the treatment results of diseases using deep learning technology is also active in the medical community. However, small patient data and specific deep learning algorithms were selected and utilized, and research was conducted to show meaningful results under specific conditions. In this study, in order to generalize the research results, patients were further expanded and subdivided to derive the results of a study predicting mortality after lung cancer diagnosis for men and women in their 80s, 90s, and 100s. Using AutoML, which provides large-scale medical information and various deep learning algorithms from the Health Insurance Review and Assessment Service, five algorithms such as Decision Tree, Random Forest, Gradient Boosting, XGBoost, and Logistic Registration were created to predict mortality rates for 84 months after lung cancer diagnosis. As a result of the study, men in their 80s and 90s had a higher mortality prediction rate than women, and women in their 100s had a higher mortality prediction rate than men. And the factor that has the greatest influence on the mortality rate was analyzed as the treatment period.

• Korean Journal of Environment and Ecology
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• v.16 no.1
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• pp.22-33
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• 2002

This study was conducted to investigate the effects of fragmentation on the bird community in Seongduck-ri and Hanggum-ri agricultural landscapes of Kangha-myon, Yangpyong-gun, Kyonggido. We analyzed the composition of tree species, forest environmental structures, structures of agricultural landscapes, avifaunas and guild structures. Number and density of tree species ranging from 6 to 10cm in D.B.H. were high in Seongduck-ri, but basal area was high in Hanggum-ri. Coverages of foliage layers under two meters and over 12 meters were high in Hanggum-ri. Meanwhile, Seongduck-ri agricultural landscapes consisted of twelve patches, dominated by Larix leptolepsis and Robinia pseudoacacia Hanggum-ri landscapes was composed of eleven patches, and dominated by Pinus rigida, Castanea crenate, Larix leptolepsis and paddy field. Dominant bird species showed the same order in two study areas, thirty-six species of birds were observed in Hanggum-ri landscapes, but twenty species were in Seongduck-ri landscapes. Number of species and density belonging to hole-, bush-, ground-nesting and water-, bush-, ground-foraging guild were high in Hanggum-ri landscapes. Number of species and density belonging to hole-nesting guild showed the high value in Hanggum-ri landscapes that was not fragmented. It could be attributed to the low human disturbance and relative high density of medium and large trees in D.B.H. Also, number of species and density belonging to bush-, ground- and water- foraging guild showed the high value in Hanggum-ri landscapes that had the high foliage amounts in the foliage layer under two meters. It will be related with the paddy field, dry field and brook, which patches covered the 28.4% of Hanggum-ri landscapes. Therefore, road not only dominate the heterogeneous patch in agricultural landscapes, but also easily cause the human disturbance. Thus, road construction would decrease the natural patch diversity and edge effects that are important for sustaining the diverse avifauna in agricultural landscapes.

• Journal of Environmental Science International
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• v.14 no.9
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• pp.817-825
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• 2005

The purpose of this study was to research about salt marsh flora and vegetation in the Dongjin-river estuary area where has a project for Sea Man Geum Reclaimed Land so that we can foster foundation on restoration of an ecological habitat, development of applicable plant and establishment of a conservation policy after deceloping the reclaimed land for salt marsh vegetation which has great value ecologically. In conclusion, we was distributed that there are 7 families 21 genera, 25 species, 2 varieties of vascular plant at the Dongjin-river estuary area which have 27 taxa in total and are $0.64\%$ among 4,191 of korean vascular plant. There are also 2 family, 2 genus, 2 species of a naturalized plant which are $1.1\%$ of indicator of a naturalized plant salt marsh vegetation of the downstream are very much affected by the time of inundation, tidal water so that a low degree of salt marsh has frequent flooding by sea water and has a pure group of Suaeda japonica. A Phragmites communis, Carex scabrifolia are distributed mainly around a waterway of salt marsh and Zoysia sinica, Atriplex subcordata, Phragmites communis are living in stock as forming into patch around medium salt marsh. Suaeda asparagoides, Phacelurus latifolius are living around a little high ground and a Phragmites communis is a behind vegetation of Phacelurus latifolius and a part of the Phragmites communis are living along with waterway in a salt marsh as a community. By the 2-M method twelve plant communities were recognized ; Suaeda japonica. Carex scabrifolia, Zoysia sinica, Artemisia scoparia, Phacelurus latifolius, Phragmites communis, Suaeda maritima, Suaeda japonica-Atriplex gmelini, Phragmites communis-Suaeda japonica, Suaeda japonica-Salicornia herbacea, Salicornia herbacea-Suaeda aspar-agoides and Scirpus planiculmis community. The actual vegetation map was constructed on the grounds of the communities classified and other data.

• The Korean Journal of Ecology
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• v.27 no.5
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• pp.269-281
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• 2004

The survey of birds in Nakdong River Basin was conducted from March in 2003 to February in 2004. This study shows that the population of birds was 94,481 individuals and 114 species. The bird recorded in Daemadeung (Ⅰ) was 21,781 individuals and 55 species. It is surrounded with silt to have a better condition for a habitat and the rest place than other areas in the Nakdong River Basin. In the traits of the groups, Grebes were well established in the lower estuary(Eulsook islet), Cormorants in the main stream of the Nakdong River and around West Nakdong River (F). Swans, Shelduck and Shorebirds were using silt in the lower estuary where the depth of water is shallow, dabbling ducks were also established in West Nakdong River (F) and Yummak (C), diving ducks in the upper Nosan Watergate in West Nakdong River (F). Besides, land birds was distributed in the Yummak (C), Eulsook islet (A) and West-Nakdong River (F). Because they are connected with the artifical forest in Eulsook Islet Garbage Field and Ⅱwoong islet, it is good for the land birds and the water birds to have a habitat in this kinds of vacant lot. The Nakdong River Basin is not only an important area as the habitat and rest place for ducks and geese but also one of the areas where we can not get out of the temptation to development. To preserve effectively the natural habitat from human s intervention, it needs to keep supervising in Daejeo Watergate (E) and the upper area Noksan watergate in West Nakdong River (F) and Yummak (C).

• The Journal of Engineering Geology
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• v.27 no.3
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• pp.313-322
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• 2017

The purpose of this study is to estimate the surface and subsurface flows through the modelling of the model area and facility agricultural complex, and to calculate the groundwater recharge rate through water budget analysis. From results of surface flow modeling, the surface water is flowed to a depth of about 1 to 5 meters from the upper region (northeast) to the lower region (southeast) of the Miryang River. At the M01 point (upper), the observed surface water flux and the model surface water flux are consistent. At the M02 points (lower), the observed surface water flux and the model surface water flux are a difference of 1%. From results of subsurface flow modeling, the depth of groundwater is similar to elevation in the river and higher to the forest area. Ground water depth considering groundwater pumping is that the model values appears higher than the observed values to be within 1.5 m. From results of surface-subsurface integrated modeling, the groundwater recharge area is estimated about 90% of the model area, and the groundwater recharge rate is estimated $1.92{\times}10^5m^3/day$. From results of annual water budget analysis, the groundwater recharge rate per unit area is estimated to be 503.9 mm/year, and average annual rainfall is estimated at around 39%.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.6
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• pp.35-50
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• 2017

This study is to see the recovery effect of the Deltacon method by investigating the amount of sand deposition, the topographical cross section and the vegetation structure; and to derive the effective recovery method of coastal erosion area. The target areas of this study include Jinri coastal dune, Bajireum coastal dune and Seopori coastal dune in Deokjeok-do Island, Ongjin-gun, Incheon. In order to assess the current status of the coastal erosion area recovery, the soil profile structure map was prepared on the site and then the amount of sand deposition within 1m was calculated indoors. The vegetation recovery status of the costal erosion area was assessed via the analyses of the topographical profile structure and the plant community structure, and we aim to derive the effective recovery plan of the Deltacon method with the results. With the Deltacon method, structures with ductile material, special non-woven fabric bags filled with soil and vegetation can be performed therefore the structuralstability and prevention of sand erosion can be achieved. The amounts of sand deposition of Bajireum coastal dune, Seopori costal dune and Jinri costal dune were calculated $0.98{\sim}2.54m^3$, $1.02{\sim}2.96m^3$, and $0.27{\sim}0.75m^3$, respectively, and it is considered that the costal erosion recovery is actively performed for Bajireum costal dune and Seopori costal dune. The analysis results of vegetation structures by topography show that the installation of the send collecting net in steep areas has been highly effective and the Deltacon-constructed target areas have been restored to vegetation and the costal dune, which is similar to the natural dune. The investigation of the plant community structure in Deokjeok-do Island costal dune, Incheon displayed similar research results of the existing costal dune flora and confirmed the emergence of Lathyrus japonicus, Carex kobomugi, Elymus mollis, Vitex rotundifolia, and Calystegia soldanella and others. In order to carry out further effective recovery with the Deltacon method, improvements to rootage of herbaceous vegetation are needed in areas without foredune herbaceous vegetation, and continuos maintenance & management monitoring of connected windbreak forest to costal dunes are also necessary.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.3
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• pp.104-118
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• 2018

This study is to evaluate the accuracy improvement of the model using SWAT(Soil and Water Assessment Tool) model and multi - point hydrological observation data. The watershed is located in the Yongdam Dam($930.4km^2$), the Donghyang($165.5km^2$), the Chuncheon($290.9km^2$), the Juchun($57.8km^2$) and the Seokjeong($80.5km^2$). The watershed covers 70.0 % forest. In order to improve the accuracy of the model, precipitation data were used from two weather stations(Jangsu, Geumsan) and 16 AWS stations daily precipitation data(2003~2011) managed by KMA, MLIT, and K-water. Based on the reliable data of the Yongam test basin in 2003~2011, the runoff of single point (Yongdam dam) and multi-point (Donghyang, Chuncheon, Jucheon, Seokjeong). Simulation results show that the $R^2$ of the single subwatershed (Donghyang, Chuncheon, Jucheon, Seokjeong) is single point(0.84) and multipoint(0.88). For model efficiency coefficient of Nash-Sutcliffe at single point(0.45) and multipoint(0.70).

• Journal of Environmental Policy
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• v.7 no.3
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• pp.141-160
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• 2008

The effects of disturbance on bird community were studied in Ssanggok Valley and Beopju Temple area, Songni Mt. National Park in $2006{\sim}2008$. We divided three sites by habitat condition such as traffic road(strong disturbance), trail(medium) and control(weak) site. During breeding and non-breeding seasons(n=12), number of species, number of individuals, species diversity and density did not differ among three sites, but in breeding season(n=9), number of species(Kruskal Wallis, $x^2$=10.32, p=0.006), number of individuals(Kruskal Wallis, $x^2$=7.118, p=0.028) and species diversity of birds(Kruskal Wallis, $x^2$=9.847, p=0.007) were significantly higher in trail site with medium disturbance than in other sites. In breeding season, nesting and foraging guild rate were not different among three sites. In guild analysis, hole was the highest nesting guild and canopy was the highest foraging guild in three sites.