• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1317-1325
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• 2016

This paper identifies the issues of contingency analysis for restoration in distribution systems. Contingency analysis has been applied to transmission systems but not to distribution systems. The distribution system is different from transmission system. So it is hard to apply for existing contingency analysis to distribution system. In this paper, a new contingency analysis method for distribution systems is proposed. The proposed method is based on service restoration capability. It aims to minimize outage left after service restoration in case of a fault in advance. The method estimates the vulnerability which is represented by zone restoration index proposed in [1]. Applying the proposed method, operators could change the system so that it does not leave any outage left after restoration. Case study has been carried out on a five feeder system and its results show effectiveness of the method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.161-168
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• 2008

The ecological environmental zones in coastal area, like tidal flat and salt marsh, were gradually decreased due to large scale of coastal development projects, reclamation and so on. Therefore, the development of artificial tidal flat and salt marsh has been emphasized in coastal area as mitigation concept and studies on related this background has performed. But studies on the quantitative evaluation for degree of restoration were insufficient. In this paper, as a fundamental study for evaluation of restoration on the creation of ecological environmental zones in coastal area, it was conducted that the monitoring and experiment for bio-chemical factors (bio-diversity, population and biomass of macro-benthos, survival ratio of reed, the number of heterotrophic bacteria and physico-chemical characteristics such as COD, IL, TN, TP and pH) using a in-situ pilot plant of tidal flat (Zone. P1) and salt marsh (Zone. P2), which was distinguished by content of dredged soil, in Jinudo, Nakdong estuary. From results of this study, the restoration index (RI), for evaluation concerning degree of restoration on the creation of ecological environmental zones in coastal area, was suggested and quantitative evaluation was performed using a restoration index (RI).

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.5
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• pp.59-76
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• 2009

This study was conducted to supply basic data for restoration and management of forests in Civilian Control Zone, with surveying naturalized plants around abandoned military camps. The total study sites are 72 abandoned military camps, from Gosung in east region to Paju in west region of Civilian Control Zone. The naturalized index of total area is 12.6%, and naturalized index of east and middle regions are 12.1% and 8.4%. But its index of west region is 15.9%. These results are due to geographical characteristics. The east and middle regions are in steep mountainous districts, and so but west region is flat district, and so naturalized plants was imported by only army. But west region is in flat districts, and so imported method of naturalized plants is very various. The main naturalized plants are Ambrosia trifida and Ambrosia artemisiifolia var. elatior in Civilian Control Zone. The main dispersion pattern of naturalized plants are gravity dispersion pattern ($D_4$) and wind and water dispersion pattern ($D_1$). The all naturalized plants are photophilic plants in survey sites. And so, if abandoned military camps are recovered to forests, the naturalized plants are disappeared because of the change of sunlight condition. So it is necessary to manage and recover forests, even if that area is Civilian Control Zone.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.3
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• pp.19-30
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• 2013

This study was proposed to adaptable species according to climate change using warmth index(WI) in Cheonan-Si. RCP 8.5 was used to estimate change of warmth index(WI) depending on climate change in Cheonan-Si. Climatic change of Cheonan-Si was estimated to change from cool temperate forest central zone to warm temperate forest zone. The following plant species will survive within WI change of Cheonan-Si from 2010 to 2050 : 18 species in the tree layer including Quercus serrata, Q. variabilis, Pinus densiflora, Q. acutissima etc.; 28 species in the shrub layer including Rhus trichocarpa, Lindera obtusiloba, Zanthoxylum schinifolium etc.; 24 species in the herb layer including Oplismenus undulatifolius, Carex lanceolata, etc.; 12 species in the vine plants including Smilax china, Cocculus trilobus, etc.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1674-1680
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• 2009

This paper proposes an autonomous fault determination, fault zone isolation and fault restoration strategy based on the ethernet communication as a new attempt to solve the problem the of the existing central control method. In proposed method, The FRTU(Feeder Remote Terminal Unit)s on the feeder determines autonomously where the faulted zone is by exchanging the voltage and current information with neighbor FRTUs based on the network communication, and then separates the faulted zone in an nil-voltage status to make the protective device to reclose successively. In particular, the minimization of outage time and relational load balancing is archived by each interconnection switch which determines autonomously the load zone to be allocated among those zones after the sound outage zones was separated individually. Finally, to show effectiveness of the proposed fault restoration strategy, the several fault cases are simulated for the test distribution system, and the load balancing index of the proposed solution is compared with all of feasible solutions.

• Journal of Korean Society on Water Environment
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• v.25 no.2
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• pp.235-244
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• 2009

The purpose of this study is to offer information about the current river conditions and basic data of streams in Busan city, by selecting 20 underground streams and evaluating their multilateral stream assessment. Concerning the evaluation of streams, 4 sections including the general index, the bank index, the river characteristic index, and the ecological environment characteristic index were evaluated. Ahead of the evaluation, the study divided Busan city into 4 zone for a systematic river investigation. Then, the study allocated code names to each river, and conducted literature research and a field survey of streams. Based on this, the study applied the evaluation of multilateral stream assessment. As a result, out of 4 entire grades, there was no grade 1 or grade 2. Instead, 35% were grade 3, 60% were grade 4, and 5% were grade 5. When looking into the evaluation results by Zone, the Dongbusan Zone showed the highest index, and the Suyeonggang Zone, the Jungbusan Zone, and the Nakdonggang Zone followed, in order.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.6
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• pp.111-117
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• 2011

This study attempts to facilitate climate change adaptation in conservation area by spatial planning of climate adaptation zone for endangered species. Spatial area is South Korea and select leopard cat (Prionailurus bengalensis) as a target species of this study. In order to specify the climate adaptation zone, firstly, Maximum entropy method (Maxent) was used to identify suitable habitat, and then core habitat was selected for leopard cat. Secondly, land use resistance index was evaluated and least cost distance was analyzed for target species. In this step we choose dispersal capacity of leopard cat to reflect species ecological characteristic. Finally, climate adaptation zone is described and adaptation measures are suggested. The presented approach could be generalized for application into conservation planning and restoration process. Furthermore, spatial planning of climate adaptation zone could increase heterogeneity of habitat and improve adaptive capacity of species and habitat itself.

• Journal of Korean Society on Water Environment
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• v.27 no.2
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• pp.218-227
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• 2011

The objective approach for assessment of stream naturalness is an essential part of the stream restoration project. This study proposes the methodology for the assessment of stream naturalness considering physical, biological and chemical factors. Physical factors consists of riffle and pool, river bed material, bank protection, floodplain vegetation and levee materials; biological factors are benthic macroinvertebrate, KSI (Korean Saprobic Index), and IBI (Index of Biological Integrity) and chemical factors are pH, DO (dissolved oxygen), and TP (total phosphorus). This procedure is applied to the Mokgamcheon. As a result, the downstream of Mokgamcheon (zone I) needs the prompt improvement of stream naturalness, compared to the others (zone II and III). This evaluation technique will be an effective tool to quantify the stream naturalness and can be used to set the target of stream restoration project.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.1
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• pp.63-72
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• 2005

Chirisan National Park, the first and largest one out of 20 national parks in Korea, is divided into five zones. They are composed of nature preservation zone, natural environment zone, natural residential zone, concentrated residential zone, and collective facility zone. However, the park is not a continuous habitat: roads, trails, local residences, and various facilities created the habitat mosaics severely fragmented. We investigated the fragmentation pattern of the park due to roads and mountain trails using GIS. Based on perimeter length, area, and the ratio of perimeter to area of each patch, we obtained landscape analysis indices which reflect the regularity of the patch shape. The 1 m-wide hiking trails divided the park into 491 fragments. The legal trails with 1.5 m - 3 m width which have been heavily used by hikers generate 58 fragments. Even the nature preservation zone, corresponding to a core zone comprising 31.8% of the park area, was divided into 37 fragments because of the roads and mountain trails. With the different widths of buffer applied, the core sizes of the fragments were reduced. When the 60 m buffer was applied, the patch interior areas ranged from 0.0001 to 47.77 $km^2$ with a mean of 7.08 $km^2$. The landscape shape indices were far greater than 1 for most of the cases with a maximum value of 25. These results clearly indicate that Chirisan National Park is not a continuous habitat, but mosaics of small, irregularly shaped habitat fragments. It is necessary to take the size and shape of the fragmented habitats into consideration when nature conservation is planned, especially for large wildlife such as brown bears.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.2
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• pp.39-56
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• 2021

The seed zone is a map that describes the areas where plant material can be transferred with little risk for properly adapting to a new location. The seed zone study is largely divided into studies based on genetic data and studies based on climatic data. Can be. This study was conducted to establish a temporary domestic seed zone applicable to the entire Korean Peninsula and evaluate its possibility based on the US climate-based seed zone establishment methodology. The temporary seed zone was constructed in the same way as the US case by superimposing the data obtained by dividing the winter minimum temperature into 12 grades and the data obtained by dividing the annual heat: moisture index into 6 grades. As a result of the analysis, 65 temporary seed zones were formed throughout the Korean Peninsula, and the areas of the seed zones representing the smallest and largest areas were 3.0km² and 29,423.0km², respectively, and it was confirmed that they had an average size of about 5,064.9km². Temporary seed zones applied in Korea show a pattern of changes in temperature according to the relatively horizontal forest zone, and it was confirmed that the area where the Baekdu-daegan ecological axis is located has a tendency to show lower dryness than other areas. This study applied the US climate-based seed zone methodology in Korea as a pilot, and confirmed the climatic similarity across the Korean Peninsula. Furthermore, it is expected to provide an optimal seed map that improves the success rate of restoration in the future by revising the seed zone grade suitable for the domestic environment in consideration of the results of this study and the possibility of seed adaptation to the field survey and environmental space.