• Korean Journal of Environment and Ecology
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• v.33 no.1
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• pp.64-74
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• 2019

The purpose of this study is to assess the degree of vegetation recovery such as the vegetation change and the effect of artificial restoration measures according to the number of years since the restoration works at the damaged Jungbong and Nuebong area in Mudeungsan National Park. We set up a total of 21 survey areas including 11 monitoring areas to analyze the flora, relative dominance, species diversity, and similarity in the restored site after relocation of Zungbong army base in 1996 and the restored site after the demolition of Neeebong telecommunication facility in 1999 and 10 control areas in the adjacent natural forest to assess the vegetation recovery in the restored sites and the nearby natural forest. The Mean Similarity Index of seed composition was relatively low at 3.5% in the Jungbong restoration site 17 years after the restoration, and the height of shrub layer, in which azaleas and furred azaleas appeared, recovered to the level of 82.6%. We concluded that it is necessary to continue monitoring the restored sites to develop the recovery assessment method and recovery work technology for sub-alpine areas in Mudeungsan National Park and other national park areas.

• Smart Structures and Systems
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• v.30 no.5
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• pp.521-535
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• 2022

Efficient management of deteriorating civil infrastructure is one of the most important research topics in many developed countries. In particular, the remote displacement measurement of bridges using linear variable differential transformers, global positioning systems, laser Doppler vibrometers, and computer vision technologies has been attempted extensively. This paper proposes a remote displacement measurement system using closed-circuit televisions (CCTVs) and a computer-vision-based method for in-situ bridge bearings having relatively large displacement due to temperature change in long term. The hardware of the system is composed of a reference target for displacement measurement, a CCTV to capture target images, a gateway to transmit images via a mobile network, and a central server to store and process transmitted images. The usage of CCTV capable of night vision capture and wireless data communication enable long-term 24-hour monitoring on wide range of bridge area. The computer vision algorithm to estimate displacement from the images involves image preprocessing for enhancing the circular features of the target, circular Hough transformation for detecting circles on the target in the whole field-of-view (FOV), and homography transformation for converting the movement of the target in the images into an actual expansion displacement. The simple target design and robust circle detection algorithm help to measure displacement using target images where the targets are far apart from each other. The proposed system is installed at the Tancheon Overpass located in Seoul, and field experiments are performed to evaluate the accuracy of circle detection and displacement measurements. The circle detection accuracy is evaluated using 28,542 images captured from 71 CCTVs installed at the testbed, and only 48 images (0.168%) fail to detect the circles on the target because of subpar imaging conditions. The accuracy of displacement measurement is evaluated using images captured for 17 days from three CCTVs; the average and root-mean-square errors are 0.10 and 0.131 mm, respectively, compared with a similar displacement measurement. The long-term operation of the system, as evaluated using 8-month data, shows high accuracy and stability of the proposed system.

• Korean Journal of Remote Sensing
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• v.39 no.6_3
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• pp.1693-1705
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• 2023

Rural areas, which account for about 90% of the country's land area, are increasing in importance and value as a space that performs various public functions. However, facilities that adversely affect residents' lives, such as livestock facilities, factories, and solar panels, are being built indiscriminately near residential areas, damaging the rural environment and landscape and lowering the quality of residents' lives. In order to prevent disorderly development in rural areas and manage rural space in a planned manner, detection and monitoring of hazardous facilities in rural areas is necessary. Data can be acquired through satellite imagery, which can be acquired periodically and provide information on the entire region. Effective detection is possible by utilizing image-based deep learning techniques using convolutional neural networks. Therefore, U-Net model, which shows high performance in semantic segmentation, was used to classify potentially hazardous facilities in rural areas. In this study, KOMPSAT ortho-mosaic optical imagery provided by the Korea Aerospace Research Institute in 2020 with a spatial resolution of 0.7 meters was used, and AI training data for livestock facilities, factories, and solar panels were produced by hand for training and inference. After training with U-Net, pixel accuracy of 0.9739 and mean Intersection over Union (mIoU) of 0.7025 were achieved. The results of this study can be used for monitoring hazardous facilities in rural areas and are expected to be used as basis for rural planning.

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.1
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• pp.137-148
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• 2006

Roadside trees that are managed by the local government play important roles to enhance the city lifestyle in many ways. However, because of insufficient human resources that monitor fields and regulations, most roadside trees were left unprotected and lacked the professional management. Also, due to the lack of financial support, pesticides or treatments have rarely been done in a proper time. To solve this existing matter, we have proposed concrete methods that include a latest communication technology, and developed an on-site management system and a web-monitoring system for roadside trees. Our successful research includes efficient approaches to identify an individual tree and integration of both field works and internal work processes with wireless communications and web displays to monitor the roadside trees.

• Korean Journal of Environment and Ecology
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• v.11 no.3
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• pp.253-269
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• 1997

This study has been surveyed the establishment and operation of nature observation facilities in the urban ecological open space of Eastern Area, Japan. Major nature observation facilities were visitor centers, nature trails and environmental facilities of nature trail. Also, interpretation as an approach to communicating and understanding of nature was progressed variously in study sites. Interpreters were park rangers and naturalists and volunteers. Major activities of the volunteers were the interpretation, environmental management and monitoring, and communication paper publication. The education materials for self-guiding of ecological open space were from two types to four types. In the advertisement methods, the advertisement through the notice paper of metropolitan, city, and destrict was the most and internet homepage, electronic communication bullentin of district, cable TV, and fax service were utilized in the four survey sites.

• Korean Journal of Environmental Biology
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• v.33 no.1
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• pp.53-62
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• 2015

We surveyed butterfly community in a rural area of the southwestern part of Korea to investigate the changes of species composition and their abundances between 2001~2002 and 2014. The butterfly survey was conducted at the same site using a line transect method. There was a significant decrease of the numbers of species and individuals between 2001~2002 and 2014. We categorized each species based on six ecological traits: habitat type, habitat breadth, food plant type, food plant breadth, number of generation per year and overwintering stage. The comparison of number of species using these ecological traits showed no difference during the 10-yr time intervals. However, the comparison of number of individuals for the ecological traits showed the significant differences except for one trait, overwintering stage. We could suspect that the decrease of butterflies in the study area was resulted from the habitat change. To investigate the causal factors and the changes of butterfly fauna, we need a long-term monitoring of the local butterfly community.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.6
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• pp.201-214
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• 2015

This study was conducted to identify forest topsoil's usefulness from July 2013 to Oct 2014. Generally, there are abundant seeds in topsoils and it can be used at restoration works. Mt. GARIWANG is famous for biodiversity in Korea. This study was aimed to find out the suitable utilization methods of natural topsoils for restoration works at sky-slopes construction sites. Test beds was made to identify suitable collecting times and suitable topsoil thickness. The main results are summarized as follows. First, Mt. GARIWANG have diverse species and in topsoils we can find lots of burried seeds which can be used at restoration works. Second, according to indoor experiment, as the depth of topsoil used thicker, the number of plants and coverage rates were increased. Also, there were no distinct differences in coverage rates between 5cm and 8cm thick topsoil plots and it can be possible to use at least 3cm thick topsoils even thou lower coverage rates. Third, as the results of research about indoor and outdoor experimental plots, there were difference in plant emergency. If we use the stabilizer to protect soil erosion, then we can get more increased results at sloped outdoor experimental plots. Fourth, based on environmental impact assessment, there was 389 species in whole region of Mt. GARIWANG. Through this seed bank experiments, we can find 23 varieties, including 4 tree varieties and 19 herbaceous varieties. We can find lots of native herbaceous species from topsoils. Fifth, this research was done at the specific area of Mt. GARIWANG and used limited topsoils. But we monitoring more longer periods, then there will be more useful outcomes. Finally by researching topsoils of Mt. GARIWANG, we can find diverse native plants. Thus, we must reuse natural topsoils of Mt. Gariwang for restoration of original vegetation.

• Journal of Ecology and Environment
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• v.30 no.4
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• pp.293-305
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• 2007

This study examined the distribution, population and vegetation structure of Corylopsis coreana in South Korea. C. coreana is distributed around the Suncheon area, Jeollanam-do, on the southern part of the Korean Peninsula, but the species is also found in Pocheon and Gangneung, on the central and central east parts of the peninsula. This discontinuous pattern of distribution is coupled with the unusual feature of only growing on northern exposed slopes. The mean density of C. coreana populations is 35 individuals per 100 $m^2$, ranging up to a maximum of 92 individuals per 100 $m^2$. Cut specimens sprouted a maximum of 38 stems per plant. Based on DCA analysis, the species' habitats was divided into three types by species composition and stratification structure. These types include: habitats affected strongly by human activities, valley and mantle communities which are affected relatively little by human activities, and stable forests. Populations affected by artificial intervention have actually flourished, while some populations in the stable forest system have declined. We conclude that the species, now endangered, should be maintained by means of specific external interventions such as cutting or removal of the canopy. To this end, further ecological data should be collected through monitoring and research to identify appropriate interventions to support threatened C. coreana populations.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.277-283
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• 2001

This paper presents treatment efficiency and plant growth of a surface-flow constructed wetland system (30 meter in length and 10 meter in width) over one year after its establishment on a floodplain of a stream. Cattails (Typha angustiflora) grown on pots were transplanted on one half of its area from inlets and reeds (Phragmites australis) on another half from an outlet. Effluent discharged from a secondary-level treatment plant was funneled into the system. The stems of cattails and reeds emerging in April 2001 grew up to 165.9 cm and 95.3 cm, respectively until July 2001. The number of stems of cattails arid reeds in July 2001 increased by 65% and 100%, respectively, compared with that just after their planting. The growth of cattails was better than that of reeds during study period. The removal rates for SS, $BOD_5$, T-N and T-P was 33%, 43%, 31%, and 51%, respectively. The system was inundated seven times by storms over the monitoring period, which disturbed its environment and led to its lower treatment rates. The increase of SS concentration in effluent after inundation of the system was attributed to the falls of soil particles onto its water surface, which had been attached to the emergent plants by floods. Purification rates for T-N were relatively low for the period of late fall through winter until early spring due to lower water temperature which may have retarded microbial nitrification and denitrification mechanisms. Reduction in T-P concentration during fall and winter was relatively higher than that during summer and spring, which may have resulted from no system perturbations by floods and heavy storms during fall and winter.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.2
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• pp.1-8
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• 1999

This study is one of the processes to build the artificial wetlands in the urban area. The purpose of this study was to survey biotic or physical environments, and to review modelling techniques to find out the ecological structure and function. Case study site was the Bangdong wetland in the north west side of Taejon metropolitan city. The number of species of insects decreased during monitoring. But the number of individuals of insects decreased abruptly after increasing. And then biodiversity index dropped and dominance index increased. So the structure of biotopes was affected by weather conditions. And in the restricted area such as urban area, the changes of insects were affected sensitively by not physical but environmental changes. As for birds, the number of species was reduced a little, but the number of individuals increased abruptly. And dominance index increased slowly. The changes of water depth and increase of temperature affected the habitat condition of vegetations and birds, so the dominance index of specific species increased. In urban areas it is necessary to continue management for water environmental changes, such as the depth and area of water. The number of species of fishes was reduced a little, but the number of individuals increased abruptly. And dominance index and biodiversity index decreased slowly. But the water environments was so changeable that it is difficult to explain current status as some specific trends. The number of species of reptiles and amphibians changed little, but the number of individuals increased abruptly. And dominance and biodiversity were not changed. The changes of water depth and temperature affected the habitat of every species the environmental changes affected.