• Korean Journal of Remote Sensing
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• v.39 no.5_4
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• pp.1145-1153
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• 2023

Urban trees play an important role in absorbing carbon dioxide from the atmosphere, improving air quality, mitigating the urban heat island effect, and providing ecosystem services. To effectively manage and conserve urban trees, accurate spatial information on their location, condition, species, and population is needed. In this study, we propose an algorithm that uses a high-resolution urban tree cover map constructed from deep learning approach to separate trees from the urban land surface and accurately detect tree locations through local maximum filtering. Instead of using a uniform filter size, we improved the tree detection performance by selecting the appropriate filter size according to the tree height in consideration of various urban growth environments. The research output, the location and height of individual trees in human settlement over Suwon, will serve as a basis for sustainable management of urban ecosystems and carbon reduction measures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.922-937
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• 2024

Maritime activities are on the rise, there is a growing demand for high-quality communication services that can cover larger areas. However, the transmission of high data rates to maritime users is challenging due to path loss from land base stations, which limits the transmission power. To overcome this challenge, researchers have been exploring the use of buoys in a marine environment as relays for communication technology. This paper proposes a simulation-based approach to investigate the impact of various beamwidths on communication performance when using a buoy as a relay. The objective is to determine the optimal beamwidth that yields the highest data rate for the target location. The approach is based on an offshore wave model where the direction of the buoy changes according to the height of the wave. The study investigates the performance of the relay in the downlink situation using receive beamforming, and the capacity at the user in the three-hop situation is verified using an amplify-and-forward (AF) relay that uses transmit beamforming to the user. The simulation results suggest that the beamwidth of the relay should be adjusted according to the wave conditions to optimize the data rate and relay position that satisfies a data rate superior to the direct path to the target position. Using a buoy as a relay can be a promising solution for enhancing maritime communications, and the simulation-based approach proposed in this paper can provide insights into how to optimize beamwidth for effective communication system design and implementation. In conclusion, the study results suggest that the use of buoys as relays for maritime communication is a feasible solution for expanding coverage and enhancing communication quality. The proposed simulation-based approach provides a useful tool for identifying relay beamwidths for achieving higher data rates in different wave conditions. These findings have significant implications for the design and deployment of communication systems in maritime environments.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.2
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• pp.109-118
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• 2010

This study aims to propose practical strategies for the new urban ideal of regeneration. A book review highlights the emergence of new trends of urbanization in knowledge-information industrial society beyond the new town Ideal of the industrial society. The meaning of ‘landscape’ in landscape urbanism represents not the visual and decorative pictures, but the dynamic process in the context of changes and evolutions. Also, knowledge-information industrial society and landscape have a meaning in the same context of flow and process with changes of velocity. Finally, these key words convey a meaning with the new urban trends of urbanization in knowledge-information industrial society in the context of value-oriented characteristics of dynamics and process. Urban regeneration is emerging as the new urban ideal in the knowledge-information industrial society, beyond the new town ideal of industrial society. It is in the same context as landscape urbanism with respect to green infrastructure buildings and designs for the transformation of urban surfaces covered with concrete and asphalt into the ecological surface, and of the ecological surfaces into the cultural surface that could be communicated with human beings. This research revealed the six strategies for urban regeneration as follows. The First, the strategies for the transformation of urban surfaces into ecological surfaces, the second, the strategies for the transformation of ecological surfaces into cultural surfaces, the third, the introduction of mixed and convergence land use, the forth, the transformation of former sites(e.g. military and factory) into urban parks, the fifth, the introduction of waterfront park zones that have the function of ecological and park-oriented mixed land use and, the sixth, the building and design of green infrastructure in the residential and commercial complex in CBD. These strategies call for the reforms of development laws and regulations to restrict building coverage ratio, building heights, and the introduction of park-oriented mixed zoning regulations. Another method for implementating the above listed strategies was the introduction of a strategic planning system instead of the traditional master plan system. This system uses a value planning approach and brand making by imagery. It is able to construct the meaning of an image and its creativeness directly.

• Korean Journal of Ecology and Environment
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• v.46 no.3
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• pp.332-342
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• 2013

We collected zooplankton from May to October, 2011, with the aim of understanding the zooplankton community distribution and food web interaction between the open water and littoral (aquatic plants) zones in two small reservoirs with different land covers (Sobudang, Myeongdong). Small-sized reservoirs are more abundant in South Korea, and a total of 51 and 65 species of zooplankton were identified at the two small reservoir (Sobudang and Myeongdong), where zooplankton densities were more abundant in the littoral zone than in the open water zone. Cladocerans and copepods densities were also higher in the littoral zone, in contrast, rotifers showed higher densities in the open water zone (t-test, P/0.05). Epiphytic zooplankton dominated at the littoral zone (Lecane, Monostyla, Alona and Chydorus) because aquatic plants provided refuge spaces for attachment. Some rotifers (e.g. Brachionus, Keratella and Polyarthra) were more abundant in the open water zone because of their small size, which might help them to go unnoticed by predators. In two-way ANOVA, rotifers related to two reservoirs or habitat space (littoral zone and open water zone), but cladocerans and copepods showed a statistically significant relationship on only two reservoirs. The results of stable isotope analysis showed that zooplankton in the littoral zone tended to depend on organic matter attached to aquatic plants as a food source, which indicates the avoidance of competition of zooplankton with other macro-invertebrates (e.g. Damselfly larva, Cybister brevis and Neocardina denticulate). As a result, zooplankton community distribution is determined by not only habitat space (aquatic plant zone and open water zone) but also by food source (phytoplankton).

• Korean Journal of Soil Science and Fertilizer
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• v.11 no.3
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• pp.145-160
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• 1979

The effects of organic material application on soil physical properties were reviewed in relation to soil productivity. The organic matter contents and soil physical properties of the cultivated land in Korea were summarized and the effects of organic matter were compared in terms of land uses and soil types. Soil physical properties related to crop yield potential, such as soil aggregation, permeability, water holding capacity, erodibility, and compactibility, were used in evaluating the effects of organic materials as a soil physical amendment. The benefical effects of organic matter addition on soil physical conditions include (1) better aeration and increased infiltration in silty and clayey soils, (2) increased water holding capacity and moisture availability in sandy soils, (3) decreased soil erodibility, and (4) increased resistance to compaction. It is, therefore, concluded that continuous application of organic materials could greatly improve the various soil physical properties and favor the growth and yield of crops. A high rate of organic matter addition could contribute to reducing not only the soil erosion on sloping land, but also the possible detrimental effect of farm mechanization. In general, the effects of organic matter on soil physical improvement were estimated to be much higher in upland than in paddy. Organic matter would have a more pronounced effect on low productive lands such as heavy clayey or sandy soils and newly reclaimed soil. The optimum level of soil organic matter content was estimated to be about 3.0 to 3.5% for the best soil physical condition. Since the organic matter contents of the cultivated lands in Korea are much lower than optimum level, it would be desiable to use more organic materials to soil for the increase of soil productivity, continuation of stabilized high productivity and soil erosion control.

• Land and Housing Review
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• v.2 no.4
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• pp.517-528
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• 2011

Indiscreet developments cause environmental problems in major cities of Seoul Metropolitan Area. Among the environmental problems, the air pollution leads the citizens' physical and economic damages. Therefore, it needs to predict how much air pollutant which is emitted from human activities can be carried by urban environment, then to examine the reasonable level of urban development This study assumed that the air pollution is represented differently by the amount of emission. With the assumption, the acceptable air pollutant emission which keeps the air quality under the environmental standard is estimated, then the proper population is calculated in the case of Gwacheon, Gyeonggi. The result is as follow: First, air pollution concentrations of CO, $NO_2$, $SO_2$ which are estimated by using IDW interpolation of GIS don't excess the air environmental standard. Second, the result of correlation analysis between air pollutant emission and air pollution concentration shows that CO and $NO_2$ has high correlationship with total source of pollution and linear source of pollution, and $SO_2$ with linear source of pollution. Third, the results of regression analysis show that the acceptable population is bigger that the real population in the case of CO, and with the estimation of $NO_2$ and $SO_2$, the current population in the urban center and boundaries where the residential and commerce land uses are concentrated is bigger than the acceptable population. The consequence of this study is that the estimation of carrying capacity can suggest the acceptable human activities which keep the air quality under the environmental standard. This can leads the sustainable urban development by control the human activities under the carrying capacity of urban environment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4B
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• pp.213-220
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• 2012

Old river channels have been formed by engineering a straight channel in Korea. This can be classified as wetland-type or land-type. The wetland-type old river channel uses parts of agricultural water supply. However, the channels have been neglected since there are problems associated with poor water quality, reduced water level, ecosystem disturbance, etc. Thus, river maintenance through preservation and restoration of old river channel can be very effective in watershed management. To achieve this, functional assessment of wetland-type old river channel is a priority need. This study applied the wetland-type channel in Mangyoung river for functional assessment. It was formed these channels with regard to the following four major criteria (Natureless, Habitat, Water-friendliness and Water quality) and 21 indices. The indices managed by measuring depending in weights. Consequently, wetland-type channel in Mangyoung river was in good condition both natureless and habitat, while it was a fragile environment in water-friendliness and water quality. In particular, the areas where it has insufficiency water and water suffering from eutrophication needs urgent improvement. This results will be used to utilize wetland-type old river channel as watershed management.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.753-767
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• 2013

Soil contamination has continuously increased worldwide, thus the remediation for the contaminated soils has risen steadily. However, the consideration of ecological safety for the remediated soils and their agricultural uses has been very limited. Therefore, this study was to investigate the influences of selected environmentally-friendly agricultural materials, organic by-product fertilizer (OF), charcoal (CC), and biochar (BC), as soil conditioners for improving poor chemical properties of fuel-oil removed soil by land farming technique. Two different remediated soils, remediated soil A (RSA) and remediated soil B (RSB), were selected. Soil texture of both RSA and RSB was sandy loam. The chemical properties of RSA and RSB were as follows: soil pHs of 8.5 and 8.7, soil organic matter contents of 7.4 and 5.5g $kg^{-1}$, total nitrogen contents of 0.26 and 0.10g $kg^{-1}$, available phosphorus concentrations of 7.2 and 4.4mg $kg^{-1}$, and exchangeable calcium concentrations of 14.8 and $11.7cmol_c$ $kg^{-1}$, respectively. Results of the properties were not reached for the optimal values for cultivating crops that were recommended by National Academy of Agricultural Science at Rural Development Administration in Korea. However, after applying OF, CC, and BC, the chemical properties of soils were selectively improved, which were that soil organic matter content and available phosphorus concentration increased, whereas the soil pH were not changed. In particular, the chemical properties were positively changed more with the application of 5.0% biochar. Thus, continuous management of the remediated soils with applying the eco-friendly agricultural materials can improve the quality of reme-diated soils.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5_2
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• pp.135-143
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• 2010

The 21st century is currently undergoing an era of urban regeneration. The purpose of this research is to secure and expand the green infrastructure with zoning regulation in the context of urban regeneration. This objective also seeks a way of urban regeneration through the use of existing large parks by employing park-based mixed use districts around the periphery of large urban parks and green spaces. This research examines the limits, problems of existing single- and mixed-use zoning districts for securing of green infrastructure by book review. This research finally advocates introducing a another type of urban mixed-use districts, namely park-based mixed use district and its characteristics and functions, by using landscape ecology and landscape urbanism as a theoretical basis. The results of this research suggested that large parks and green spaces should be considered as one of patch in landscape ecology. This research also discusses the possibility that, as patches have ecotones with greater biodiversity in the peripheral areas of it, the green infrastructure can be constructed around the periphery of large urban large parks and green spaces by introducing cultural ecotone of nature's convergence with the city. As a result, the green infrastructure and high density of land use and using behaviour can be increased. Park-based mixed use districts encourage the convergence of parks and the city, with the park being used as the main function; residential, commercial, business and cultural uses etc. are partial functions. In order for the park-based mixed use districts to be designated, the size of large urban parks and green spaces, as well as location, city function and condition of the peripheral areas all need to be considered. The necessity to examine the designated width of the park-based mixed use districts and the form of the peripheral area was also discussed. This research, which is based on investigative research results, suggests that further in-depth and comprehensive analysis of the actual condition of urban large parks and peripheral areas needs to be completed. Specialists and other interested parties, analysis and investigation on related plans and designs are also needed for the institutional practice.

• Journal of Korean Society of Forest Science
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• v.109 no.2
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• pp.124-135
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• 2020

Alder (Alnus japonica) forests are representative of the wetland in East Asia, including Korea. In the past, alder forests were relatively common in various habitats such as mountains, riversides, back marshes, and alluvial plains. However, this plant community has recently become rare due to increasingly arid habitats and the influence of various land uses. In this study, we identify the synecological characteristics of alder (A. japonica) forests distributed naturally in the mountainous wetlands of Korea and provide basic data for their systematic conservation and management in the future. Based on vegetation survey data collected from 66 alder forests, community types were classified using the methods of the Zürich-Montpellier School of Phytosociology and two-way indicator species analysis. There were eight community types: Styrax obassia, Weigela subsessilis-Fraxinus mandschurica, Spiraea fritschiana, Viola verecunda, Impatiens textori-Spiraea salicifolia, Glyceria leptolepis, Molinia japonica, and Lindera obtusiloba-Quercus acutissima. These community types constituted a vegetation unit hierarchy of two communities, four subcommunities, and eight variants. In addition, the ecological characteristics of each community type were compared (including total coverage per 100 square meter, importance value index, constancy class, life-form composition, diversity indices, community similarity coefficient, and indicator species).