• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.6
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• pp.109-126
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• 2015

This study is for constructing detailed data to secure biological diversity and maintain a healthy ecosystem in Backsasil Valley Ecological and Scenery Conservation Area, and for preparing an ecological management plan fit for the protected area. The period for this study was from April 2010 to May 2013. Recently, the increase of visitors to Baeksasil Valley, as well as the plantation and dissemination of introduced vegetable species, become factors accelerating ecological disturbance. Major research contents included the reviews of the management system of the protected areas, the necessity of ecological management at the basin level, establishing the system of a management plan, research and analysis of environment ecology, analysis of threatening factors, goal-setting, management strategies, and a plan through SWOT analysis. Survey items were the natural environment, major components of ecosystem, and human-use. The goals of ecological management were basin zone management for amphibians, conservation and restoration of forest vegetation for conservation habitat of Dryocopus martius, conservation habitat of Zelkova serrta for nature landscape, and management of users for environment protection. The conservation management plan at a basin zone level contains the management of point and non-point pollution sources in the upstream, securing growing conditions for native plants, securing safe habitats for amphibians, and securing of habitats for major wild birds. Also, restoration of natural forests, management of native plants and introduced vegetable species, and restoration of degraded forest paths are suggested for the restoration plans.

• Korean Journal of Remote Sensing
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• v.29 no.4
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• pp.389-397
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• 2013

Recently high spatial resolution space-borne Synthetic Aperture Radar (SAR) systems have launched and have been operated successfully. Interferometric SAR (InSAR) processing with the space-based high resolution observations acquired by these systems can provide more detail information for various geodetic applications. Coherence is regarded as a critical parameter in the evaluating the quality of an InSAR pair. In this study, we evaluate the coherence characteristics of high-resolution data acquired by TerraSAR-X (X-band) and ALOS PALSAR (L-band) and intermediate-resolution data acquired by Envisat ASAR (C-band) over western Texas, U.S.A. Our coherence analysis reveals that the high-resolution X-band TSX (3.1 cm) data has a high coherence level (0.3-0.6), similar to that of the L-band ALOS PALSAR data (23.5 cm) in short temporal baselines. Further more, the TSX coherence values are significantly higher than those of the C-band (5.6 cm) Envisat ASAR data. The higher coherence of the TSX dataset is a surprising result, because common scattering theories suggest that the longer wavelength SAR data maintain better coherence. In vegetated areas the shorter wavelength radar pulse interacts mostly with upper sections of the vegetation and, hence, does not provide good correlation over time in InSAR pairs. Thus, we suggest that the higher coherence values of the TSX data reflect the data's high-resolution, in which stable and coherent scatters are better maintained. Although, however, the TSX data show a very good coherence with short temporal baseline (11-33 days), the coherences are significantly degraded as the temporal baselines are increased. This result confirms previous studies showing that the coherence has a strong dependency on the temporal baseline.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.27-46
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• 1996

The purpose of this study was designed to compare with the effects of 4 different surface active bioceramics on the healing process of alveolar bone defects in dogs. Artificial alveolar bone defects depth 4-6mm, width 3-4mm) were created with # 6 round bur at interproximal areas of maxillary canine, maxillary 2nd premolar, mandibular canine, and mandibular 3rd premolar. porous hydroxyapatite(Interpore $200^R$) , 45S5 bioglass, CJ4/lOC crystalline glass, and JJ crystalline glass were implanted in intrabony defects randomly. Experimental groups were divided into 4 categories according to its implant material. After implantation, all groups were examined postoperatively 4 weeks to 12 weeks. 3 dogs was selected randomly and sacrificed after vascular perfusion with 2.5% glutaraldehyde at every 4 weeks. Tissue blocks with surroundig alveolar bone and soft tissues were removed and immersed in formaldehyde/glutaraldehyde fixative. After 20 weeks decalcification with EDTA and formic acid, sections were made and observed under light microscope and transmission electron microscope. In all experimental groups, the encapsulation of inactive connective tissue was observed around graft particles in 4 weeks. As time elapsed, the thickness of surrounding connective tissue was decreased. Osteoconductive bone growth pattern was seen apparently in all groups. CJ4/lOC crystalline glass showed the most active bone formation until 8 weeks. 45S5 bioglass was, however, the most active in new bone formation at 12 weeks. Though there was difference in resorption rate among grafting materials, the size of graft particles was decreased gradually. 45S5 bioglass was resorbed faster than the others. On the other hand, porous hydroxyapatite was degraded most slowly. Phagocytosed particulate matters was observed in the cytoplasm of multinuclear multinuclear giant cell and macrophage under transmission electron microscope. The results suggested suggested that 45S5 bioglass and CJ4/lOC crystalline glass may have some enhanced reparative potential when compared to porous hydroxapatite in the treatment of periodontal defeds. JJ crystalline glass reguires a further investigation of the safety of its use.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.20 no.4
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• pp.43-61
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• 2017

The wetlands are facing environmental changes such as desiccation that occurs with the passage of time and reduced ecosystem services from wetlands in the city. In order to maintain the ecosystem services provided by wetlands in urban areas, a system thinking about the trade-off phenomenon of ecosystem services occurring as the wetlands undergo environmental changes is needed. Therefore, the purpose of this study is to develop strategies for wetland design using system thinking approach to enhance the resilience of ecosystem services degraded by the desiccation of wetlands and other disturbances. The objectives of this study include the system boundary and variables. Second, analyzing the dynamics of wetland design strategy. Third, it analyzes the trade-off phenomenon of ecosystem services in terms of the hydrology, hydric soil, and plants strategies to mitigate these effects. Fourth, wetland basic design to improve the resilience of ecosystem services. A wetland in Abuk-Mountain Neighborhood Park, Miryang-si, Gyeongsangnam-do, has been selected as a case study. Causal loop diagrams(CLDs) are used to analyze feedback in the wetland regime. In summary, hydrology, hydric soil, and plants is suggested as system boundaries to design plan. Design strategies for the wetland focused on robustness, redundancy, rapidity, and resourcefulness as a result of CLD analysis are first proposed in order to effectively maintain the wetland regime over the long term. Secondly, in a section related to hydrology, the CLD results show the trade-offs between provisioning-cultural services and regulating services. In order to control these services, a "water cycling system" has been implemented due to its strength in terms of robustness. The CLDs for hydric soil showed the trade-offs between regulating services and supporting services. An "installation of storm drainage for maintaining water levels" was selected due to the strength offered in terms of redundancy and rapidity. The CLDs for plants showed the trade-offs between provisioning - cultural services and regulating services. In order to control the strategic points, the "planting of indigenous vegetation" was suggested given the strength in terms of redundancy. In this study, a wetland design method is proposed that can improve the resilience of wetland ecosystem services by analyzing the dynamics overtime. The results of this research can theoretically be applied to help restore ecosystem services in wetlands using ecological landscape design. In addition, this study will contribute to reducing maintenance costs by improving wetland resilience.

• Korean Journal of Materials Research
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• v.8 no.6
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• pp.493-498
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• 1998

CdTe films were deposited by close spaced sublimation with various substrate temperatures, cell areas, and thicknesses of CdTe and ITO layers and their effects on the CdS/CdTe solar cells were investigated. The resistivity of CdTe layers employed in this study was 3$\times$ $10^{4}$$\Omega$cm For constant substrate temperature the optimum substrate ternperature for CdTe deposition was $600^{\circ}C$. To obtain larger grain size and more compact microstructure, CdTe film was initially deposited at 62$0^{\circ}C$, and then deposited at 54$0^{\circ}C$. The CdTe film was annealed at 62$0^{\circ}C$ and $600^{\circ}C$ sequentially to maintain the CdTe film quality. The photovoitaic cell efficiency improved by the "two-wave" process. For constant substrate temperature, the optimum thickness for CdTe was 5-6$\mu m$. Above 6$\mu m$ CdTe thickness, the bulk resistance of CdTe film degraded the cell performance. As the cell area increased the $V_{oc}$ remained almost constant, while $J_{sc}$ and FF strongly decreased because of the increase of lateral resistance of the ITO layer. The optimum thickness of the ITa layer in this study was 300~450nm. In this experiment we obtained the efficiency of 9.4% in the O.5cm' cells. The series resistance of the cell should be further reduced to increase the fill factor and improve the efficiency.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.15-23
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• 2004

Deicer operations provide traffic safety during winter driving conditions in urban areas. Using large quantities of de-icing chemicals (i.e., $CaCl_2$ and NaCl) can cause serious environmental problems and may change behaviors of heavy metals in roadside sediments, resulting in an increase in mobilization of heavy metals due to complexation of heavy metals with chloride ions. To examine effect of de-icing salt concentration on the leaching behaviors and mobility of heavy metals (cadmium, zinc, copper, lead, arsenic, nickel, chromium, cobalt, manganese, and iron), leaching experiments were conducted on roadside sediments collected from Seoul city using de-icing salt solutions having various concentrations (0.01-5.0M). Results indicate that zinc, copper, and manganese in roadside sediments were easily mobilized, whereas chromium and cobalt remain strongly fixed. The zinc, copper and manganese concentrations measured in the leaching experiments were relatively high. De-icing salts can cause a decrease in partitioning between adsorbed (or precipitated) and dissolved metals, resulting in an increase in concentrations of dissolved metals in salt laden snowmelt. As a result, run-off water quality can be degraded. The de-icing salt applied on the road surface also lead to infiltration and contamination of heavy metal to groundwater.

• Journal of Ecology and Environment
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• v.45 no.3
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• pp.105-116
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• 2021

Background: The creation of the National Institute of Ecology began as a national alternative project to preserve mudflats instead of constructing the industrial complexes by reclamation, and achieve regional development. On the other hand, at the national level, the research institute for ecology was needed to cope with the worsening conditions for maintaining biodiversity due to accelerated climate change such as global warming and increased demand for development. In order to meet these needs, the National Institute of Ecology has the following objectives: (1) carries out studies for ecosystem change due to climate change and biodiversity conservation, (2) performs ecological education to the public through exhibition of various ecosystem models, and (3) promotes regional development through the ecological industry. Furthermore, to achieve these objectives, the National Institute of Ecology thoroughly followed the basic principles of ecology, especially restoration ecology, in the process of its construction. We introduce the principles and cases of ecological restoration applied in the process. Results: We minimized the impact on the ecosystem in order to harmonize with the surrounding environment in all the processes of construction. We pursued passive restoration following the principle of ecological restoration as a process of assisting the recovery of an ecosystem degraded for all the space except in land where artificial facilities were introduced. Reference information was applied thoroughly in the process of active restoration to create biome around the world, Korean peninsula forests, and wetland ecosystems. In order to realize true restoration, we pursued the ecological restoration in a landscape level as the follows. We moved the local road 6 and high-voltage power lines to underground to ensure ecological connectivity within the National Institute of Ecology campus. To enhance ecological diversity, we introduced perch poles and islands as well as floating leaved, emerged, wetland, and riparian plants in wetlands and mantle communities around the forests of the Korean Peninsula in the terrestrial ecosystem. Furthermore, in order to make the public aware of the importance of the intact nature, the low-lying landscape elements, which have disappeared due to excessive land use in most areas of Korea, was created by imitating demilitarized zone (DMZ) landscape that has these landscape elements. Conclusions: The National Institute of Ecology was created in an eco-friendly way by thoroughly reflecting the principles of ecology to suit its status and thus the impact on the existing ecosystem was minimized. This concept was also designed to be reflected in the process of operation. The results have become real, and a result of analysis on carbon budget analysis is approaching the carbon neutrality.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.283-296
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• 2008

The Urban Stream Assessment Technique (USAT) was suggested to give information about present urban stream condition. Domestic and foreign stream evaluation methods were analyzed and some streams were previously investigated to decide evaluation factors that could evaluate stream condition and have concern with characteristics and flood control of urban stream. The USAT consisted of three steps. High step has three characteristics concerned with functions of stream such as flood risk, stream, and ecology. In middle step, three characteristics were subdivided by ten features to describe changes and degradations of urban stream. Low step consisted of fifty three factors that explain the present condition of ten features. A survey of river experts was conducted to reflect weight among characteristics and features. The weights were calculated by analytic hierarchy process(AHP). The USAT was carried out to check over application of that in Suwon, Anyang, and Joongrang stream. The results of stream evaluation were expressed by factor index, feature index, characteristic index, total index, and evaluation grade. The results of the USAT were useful to realize changed and degraded areas. It is expected that the USAT can be used as base investigation for restoring and managing urban streams.

• Korean Journal of Remote Sensing
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• v.34 no.5
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• pp.811-827
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• 2018

The purpose of this study is to compare machine learning algorithm and deep learning algorithm in crop classification using multi-temporal remote sensing data. For this, impacts of machine learning and deep learning algorithms on (a) hyper-parameter and (2) training sample size were compared and analyzed for Haenam-gun, Korea and Illinois State, USA. In the comparison experiment, support vector machine (SVM) was applied as machine learning algorithm and convolutional neural network (CNN) was applied as deep learning algorithm. In particular, 2D-CNN considering 2-dimensional spatial information and 3D-CNN with extended time dimension from 2D-CNN were applied as CNN. As a result of the experiment, it was found that the hyper-parameter values of CNN, considering various hyper-parameter, defined in the two study areas were similar compared with SVM. Based on this result, although it takes much time to optimize the model in CNN, it is considered that it is possible to apply transfer learning that can extend optimized CNN model to other regions. Then, in the experiment results with various training sample size, the impact of that on CNN was larger than SVM. In particular, this impact was exaggerated in Illinois State with heterogeneous spatial patterns. In addition, the lowest classification performance of 3D-CNN was presented in Illinois State, which is considered to be due to over-fitting as complexity of the model. That is, the classification performance was relatively degraded due to heterogeneous patterns and noise effect of input data, although the training accuracy of 3D-CNN model was high. This result simply that a proper classification algorithms should be selected considering spatial characteristics of study areas. Also, a large amount of training samples is necessary to guarantee higher classification performance in CNN, particularly in 3D-CNN.

• Economic and Environmental Geology
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• v.6 no.1
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• pp.29-64
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• 1973

A land resources survey in the semi-arid area, Mula in S. E. Spain, of $400km^2$ is compiled. The basic aim of the project is to investigate the intrinsic qualities of the land resources of the area by means of applying an integrated method of natural resources survey mainly concerning with analysis and synthesis of land complexes, each of them represents an area or a group of areas with similar patterns of landforms, soils and vegetation, based on a geomorphological approach. The area is characterized by a linear arrangement of relief pattern with an asymmetric homoclinal repetition of slope attitudes elongating WSW-ENE, dipping steeply on the NW sides and gently on the SE sides, which have been resulted from the post-Alpine folding of the Triassic to Cretaceous limestone, the Eocene limestone, the Oligocene sandstone and the lower Miocene limestone and marl, and the post-lower Miocene faulting, tilting and subsequent differential erosion of the Miocene sedimentary formations. An integrated body of information in geology, landforms, soils and vegetation, which are significantry interrelated as an environmental complex, has been obtained. Using this data, 26 land complexes developing on the various situations of landforms, such as folded mountain ranges, tilted tablelands, bevelled cuestas, degraded hill-lands associating with enormous foots lopes, undulating terrains and terraced or flat plains, have been differentiated, mapped and described. The soils of the area are mostly light colored calcic lithosols which have been derived dominantly from the marly parent materials and developed into remarkable slope catenas in some places depending on the relief conditions. The land uses of the area are mainly characterized by the perennially irrigated cultivation of citrus orchards along the terraced alluvial deposits fringing the Segura and Mula River, and the dry-land cereal cultivation on gentler slopes. Pioneer dry-land cultivations within the shrubs on steeper slopes are restricted to the unchannelled tributary drainage floors. The availability of water is a fundamental controlling factor for existence of native and cultivated vegetation as a whole, and a number of active processes including sheet wash and gully erosion, especially on the scarp slopes, are the other important factors to be considered in conservation and management of the land in the area.