• Land and Housing Review
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• v.5 no.4
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• pp.235-246
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• 2014

In the late 1980s, 5 new towns such as Bundang, Ilsan, Pyeongchon, Sanborn, Jungdong were constructed to solve housing problems and to disperse functions concentrated within Seoul. As the city got matured, it began to appear the initial signs of urban problems such as aging of high rise-density apartment sites, traffic congestion, lack of parking spaces and aging of infrastructure. Therefore, in order to cope with urban problems, it is very important to apprehend the process of urban growth, its change and the feature of physical/human elements. So, the purpose of this thesis is to analyze the changes in housing and population characteristics for past 20 years by use of Census data from 1995 to 2010. First, the new town's goal of population and housing plan at the time of construction was analyzed how it was achieved, and it is close to the performance of the goal. And the trend of changes in the population and household characteristics was analyzed by every five year's data. As the result of analysis, it shows socio-demographic changes such as aged and elderly population growth, rapid increase in one generation's household and single person household, highly educated city, monthly rent household's increase and charter household's reduction. Results of this analysis can be utilized to aforethought management of new towns. But it is required more sustained and systematic urban monitoring and data analysis because the one-off analysis of the city's characteristics alone is difficult enough to grasp them.

• Journal of Life Science
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• v.25 no.4
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• pp.369-375
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• 2015

Data on the spatial distribution of a plant population among administrative areas is useful for various purposes. In this study, I analyzed the spatial distribution of the geographical distances of Carex siderosticta at Mt. Geumjeong and Mt. Ahop in Korea. The aim was to test a spatial structure within two populations of C. siderosticta. Most natural plots of C. siderosticta are not uniformly distributed in the forest community; for example, uniform plots were aggregately distributed within a space of 6.0 m $\times$ 6.0 m. When the sampling plots were larger than 6.0 m $\times$ 12.0 m, the individuals of C. siderosticta were aggregately distributed. The neighboring patches of C. siderosticta were predominantly 7.5 m to 9.0 m apart, on average; however, if the natural populations were disturbed by human activities, the aggregation occurred in shorter distances than a scale of 9.0 m. Moran's I of C. siderosticta significantly differed from the expected value in only 16 of 40 cases (40%). In conclusion, the geographical distribution of C. siderosticta is not even, with varying degrees of size in the plots, while human activities give rise to density effects in the plots at both Mt. Geumjeong and Mt. Ahop in Korea.

• Journal of Ecology and Environment
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• v.45 no.4
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• pp.237-254
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• 2021

Background: Some of the introduced alien species introduced settle, multiply, and spread to become invasive alien species (IAS) that threaten biodiversity. To prevent this, Korea and other countries legally designate and manage alien species that pose a risk to the environment. Moreover, 2160 alien species have been introduced in South Korea, of which 1826 animals and 334 plants are designated. The inflow of IAS can have negative effects such as ecosystem disturbance, habitat destruction, economic damage, and health damage to humans. To prevent damage caused by the inflow of IAS in advance, species that could potentially pose a risk to the environment if introduced in South Korea were designated as alert alien species (AAS). Results: The designation criteria were in accordance with the "Act on the Conservation and Use of Biological Diversity" and the "Regulations on the Ecological Risk Assessment of AAS and IAS" by the National Institute of Ecology. The analysis result of risk and damage cases indicated that mammals affect predation, competition, human economic activity, virus infection, and parasite infection. Birds have been demonstrated to affect predation, competition, human economic activity, and health. It was indicated that plants intrude on the ecosystem by competing with native species with their high-population density and capacity to multiply and cause allergic inducement. Interestingly, 300 species, including 25 mammals, 7 birds, 84 fishes, 28 amphibians, 22 reptiles, 1 insect, 32 spiders, 1 mollusk, 1 arthropod, and 99 plants, are included in the list of AAS. Conclusions: AAS designation plays a role in preventing the reduction of biodiversity by IAS in South Korea and preserving native species. Moreover, it is determined to provide considerable economic benefits by preventing socio-economic losses and ecological damage.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.3
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• pp.29-42
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• 2023

As the destruction of habitats due to recent development continues, there is also increasing interest in endangered species. Mankyua chejuense is a vulnerable species that is sensitive to changes in population and habitat, and it has recently been upgraded from Endangered Species II to Endangered Species I, requiring significant management efforts. So in this study, we analyzed the potential habitats of Mankyua chejuense using MaxEnt(Maximum Entropy) modeling. We developed three models: one that considered only environmental characteristics, one that considered artificial factors, and one that reflected the habitat of dominant tree species in the overstory. Based on previous studies, we incorporated environmental and human influence factors for the habitats of Mankyua chejuense into spatial information, and we also used the habitat distribution models of dominant tree species, including Ulmus parvifolia, Maclura tricuspidata, and Ligustrum obtusifolium, that have been previously identified as major overstory species of Mankyua chejuense. Our analysis revealed that rock exposure, elevation, slope, forest type, building density, and soil type were the main factors determining the potential habitat of Mankyua chejuense. Differences among the three models were observed in the edges of the habitats due to human influence factors, and results varied depending on the similarity of the habitats of Mankyua chejuense and the dominant tree species in the overstory. The potential habitats of Mankyua chejuense presented in this study include areas where the species could potentially inhabit in addition to existing habitats. Therefore, these results can be used for the conservation and management planning of Mankyua chejuense.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.238-250
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• 2020

This study investigated the long-term measures to minimize flood damage in the event of flooding in urban areas. The relationship between urban spatial factors and the impact of flood damage was analyzed, focusing on non-structural measures. The urban spatial factors were categorized into three parts: open space, disaster prevention facilities, and urbanization sectors. Multiple regression analysis was used to investigate how urban spatial factors influence flood damage. As a result of the analysis, the crucial factors, such as the reduced green areas and parks included in the open space sectors, resulted in an increased flood damage potential. The posterior factors, such as the population density and GRDP included in the urbanization sector concurrently led to an increase in the flood damage potential. Therefore, to better adapt to climate change, it is necessary to establish urban spatial plans strategically, such as green areas and parks. Meanwhile, the population density and GRDP are also the main factors causing flood damage. Therefore, when used appropriately in terms of resilience, it will serve as adaptations and recovery.

• Journal of Life Science
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• v.26 no.8
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• pp.881-886
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• 2016

Cephalanthera erecta (Thunb. ex, Murray) is an herbaceous and a member of the genus Cephalanthera in the family Orchidaceae. The species is an herbaceous and has reputed Chinese medicinal value. It has been investigated the population density and spatial distribution of this species at Mt. Ahop in Korea during 2015. The spatial pattern of C. erecta was analyzed according to several patchiness indexes, population uniformity or aggregation under different sizes of plots by dispersion indices, and spatial autocorrelation. The mean crowding (M*) and patchiness index (PAI) showed positive values except one small plot (2 m × 2 m). Most natural individuals of C. erecta for plots were not uniformly distributed in the forest community. The small plots (2 m × 2 m, to 8 m × 16 m) of C. erecta were uniformly distributed in the forest community and large plots (16 m × 16 m and 16 m × 32 m) were aggregately distributed. Significant aggregations by Moran's I of C. erecta were partially observed within IV classes (12 m). Dissimilarity among pairs of individuals could found by more than 18.0 m. In conclusion, the geographic distribution of C. erecta is not even with varying degrees of size of plots and human activities give rise to density effects in the plots at Mt. Ahop in Korea.

• Korean Journal of Environment and Ecology
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• v.34 no.1
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• pp.9-17
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• 2020

Domestic cats (Felis catus) introduced to insular environments can be invasive predators that often threaten endemic species and cause biodiversity loss or local extinction on the island. This study was conducted from March to July 2018 to understand the population size, home range, and spatial use of cats introduced to Mara Islet (N 33° 07', E 126° 16') in Jeju Special Governing Province, the Republic of Korea. Observation records based on their natural marks revealed that there were 20 adult cats on Mara Islet. A capture-recapture method also estimated 20 adult individuals (95% confidence interval: 20-24 individuals). According to our telemetry study on ten adults deployed with GPS-based telemetry units, the home range size was 12.05±6.99 ha (95% KDE: kernel density estimation), and the core habitat size was 1.60±0.77 ha (50% KDE). There were no significant differences in the home range and core habitat sizes by sex. The home range of domestic cats overlapped with the human residential area, where they might secure easy foods. Five of ten tracked cats were active at potential breeding colonies for the Crested Murrlet (Synthliboramphus wumizusume), and six approached potential breeding areas of the Styan's Grasshopper Warbler (Locustella pleskei), suggesting the predation risk of the two endangered species by cats. This study provides novel information on the population size and home range of introduced cats on Mara Islet which is an important stopover site of migratory birds as well as a breeding habitat of the two endangered avian species. Reducing the potential negative impacts of the introduced cats on migratory birds and the endangered species on Mara Islet requires monitoring of the predation rate of birds by cats, the population trends of cats and endangered breeding birds as well as the effective cat population control and management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.455-464
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• 2015

Investments into existing cultural facilities are determined based on administrative district-based indices like population and area. Such macro judgment indices, however, fail to consider accessibility of cultural facilities from neighboring administrative districts and thus create problems including wasted budgets and duplicated investments. More recently, the government has made it a goal to increase the level of citizen awareness of these facilities, but achieving this requires the integration of neighboring administrative districts such that characteristics including transportation network and buildings are reflected in a comprehensive manner. This research therefore looks into Urban Network Analysis (UNA) as a means to investigate accessibility of cultural facilities. Use of UNA will make it possible to analyze the transportation network as well as building distribution, explained by building density, settled population, and other important building factors, in tandem, leading to the concentration of cultural facilities and the surrounding economic district being more properly reflected, and thus allowing for greater explanatory power in determining the level of accessibility. To test this, four target research districts were chosen from within the Gyeonggi Province and analyzed in terms of the accessibility of their everyday cultural facilities. Of the four districts of Gunpo, Anyang, Uiwang, and Gwacheon, accessibility of the first two districts, was found to be high, while accessibility was found to be relatively low for the latter two districts. This finding indicates that cultural facilities investments should be concentrated in the districts of Gunpo and Anyang.

• Journal of Radiation Protection and Research
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• v.33 no.2
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• pp.67-76
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• 2008

As the first comprehensive attempt at a national implementation, this study aims at assessing the external costs of major electricity generation technologies in Korea, particularly an evaluation of the impacts on human health resulting from exposures to atmospheric radiological emissions from nuclear power plants, and a monetary quantification of their damages. The methodology used for the assessment of the externalities of the selected fuel cycles has been developed by the International Atomic Energy Agency (IAEA), namely the SimPacts Model Package. The model is internationally recognized as a tool which can be applied to a wide range of fuels, different technologies and locations, for an externalities study. In this study, the relevant emissions are quantified first and then their impacts on human health are evaluated and compared. The study focused on all the nuclear power plants for the last 6 years ($2001{\sim}2006$) in Korea. With respect to nuclear power, the impact analysis only focuses on a power generation, however the front- and back-end nuclear fuel cycles are not included, namely uranium mining, conversion, enrichment, reprocessing, conditioning, etc., because these facilities are not present in Korea. The analysis results show that nuclear power in general, generates low external costs. The highest damage costs from the nuclear power plants among the 4 sites in Korea were estimated to be 3.9 mills/MWh, which is about 1/20th of the result for a similar case study conducted in the U.K., implemented through the ExternE project. This difference is largely due to the number of radionuclides included in the study and the amount of released radioactive emissions based on up-to-date information in Korea. In this study, the sensitivities of the major factors for nuclear power plants were also calculated. The analysis indicates that there was around a ${\pm}3%$ damage costs variation to a ${\pm}15%$ change of the reference population density and a ${\pm}1%$ damage cost variation to a $1{\sim}30$ meters change of the effective release height, respectively. These sensitive calculations show that there is only a minor difference when the reference costs are compared.

• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.14-27
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• 1990

The vegetation of Pyeongil island was ecologically investigated four times from July, 1979 to May, 1981. The vegetation of this island consisted of 80 families, 172 genera, 173 species, 21 varieties and 4 forma. Evergreen, broad-leaved trees comprised a total of 11 species including Eurya japonica Thunb. and Trachelostermum asiaticum var. intermedium Nakai. The distribution of evergreen, broad-leaved trees was very spares in this island as a whole. It may also be considered that evergreen, broad-leaved trees, such as Camellia japonica Linne (30cm-35cm in diameter at breast height), Pittosporum fobira Aiton, Eurya japonica Thunb. and Trachelostermum asiaticum var. intermedium Nakai which might have been dominant species on this island, have undergone artificial succession caused by the planting of Pinus thunbergii Parl. dominant species of today. This was due to human interferences for fuel, building, grazing and farmland use. Especially, the vegetation of this island seems to have been severely destroyed by high population density, farming rate and by rapid increase in the area of cultivated land. However, the forest of Pinus thunbergii Parlatore at Wolsong-ri is worthy of conservation. The five species of seaside plants (Ixeris dentata (Thunb.) Nakai, Rosa rugosa Thunb., Carex laticeps Clarke, Calystergia soldanella Reom. et Schult. and Phelloterus littoradis) were distributed in the vicinity of sand beaches leading to Wolsong-ri, Dongbaeg-ri and Sadong-ri.