• Journal of Electrical Engineering and Technology
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• 제4권4호
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• pp.451-456
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• 2009

Through the development of phasor measurement units (PMU), various aspects of power system dynamic behavior could be monitored and diagnosed. Monitoring dynamic voltage stability has become one of the achievements we can obtain from PMUs. It is very important to select the most appropriate method for the Korea Electric Power Corporation (KEPCO) system since there are many voltage stability indices. In this paper, we propose an advanced WAVI (Wide Area Voltage Stability) that is well suited for the purposes of monitoring the dynamic voltage stability of KEPCO's PMU installation plan. The salient features of the proposed index are: i) it uses only PMU measurements without coupling with EMS data; ii) it is computationally unburdened and can be applied to real-time situations. The proposed index is applied to the KEPCO test system and the results show that it successfully predicts voltage instability through comparative studies.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.609-612
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• 2006

Concrete structures in the seashore are greatly affected by salt attack primarily due to airborne chlorides like it can be seen through the corrosion of rebar. This study intends to investigate characteristics on the salinity of the airborne chlorides in terms of areas. Salinity measurement devices were installed at 27 areas along with seashore throughout the country. The area index for airborne chlorides were established according to the measurements. In Gochang and Taean area showed higher value of area index over 10. In addition, the Eastern coast showed higher index compared to the Western and Southern coast.

• Journal of Construction Engineering and Project Management
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• 제2권4호
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• pp.32-41
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• 2012

In recent times, multi-centralization and decentralization as well as large Capital area and suburbanization in the spatial structure of capital area. With rapid growth, urbanization and industrialization are unsystematic, and growth inequality between regions caused negative effects such as discordant centralization and decentralization, fluctuating land value, and gap between living conditions. Accordingly, this study analyzed urban spatial indexes by the self-governed body in the capital area such as Seoul, Incheon, and Gyeonggi province for the analysis of the regional inequality phenomenon. We examined the characteristics of temporal and spatial changes in urban spatial structure in the capital area by utilizing the distribution pattern and density of city indexes such as population, employment, etc, and then drew the commonality of those factors through factor analysis. We evaluated the drawn results through the city standard index by each city, conducted factor score analysis, and identified the interaction between each factor and Housing Purchase Price Composite Indices index, housing rent price index(Housing Jeonse Price Composite Indices), land price fluctuation rate, diffusion ratio of house, and financial independence.

• Journal of Ginseng Research
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• 제15권1호
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• pp.31-35
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• 1991

In order to know the optimum planting density under shading structures at different light intensity, We investigated the growth status, distribution of ginseng leaf area, correlation between planting density and root weight per plant and yield, correlation between leaf area index and root weight per plant and yield. According to the increase of planting density the leaf area per plant was decreased, but leaf area index (L.A.I) was increased. Ginseng leaf population at different lines under common straw shading were distributed mainly in frost lines but polyethylene net shading at 10fo light intensity were distributed equally in all lines. Optimum planting density in common straw shading at 5% light intensity was 55 plant per tan (90 cmX180 cm) and polyethylene net shading 81 10% light intensity was 60 plant per tan, in consideration of root weight and yield. Optimum leaf area index was 2.4 under common straw shading at 5% light intensity but was 2.7 under polyethylene net shading at 10% light intensity.

• 한국환경과학회지
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• 제12권2호
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• pp.163-170
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• 2003

Seosan A, B area is located on 36°42' of north parallel and 126°27' of east longitude. It consisted of broad artificial lakes and reclaimed agricultural lands; there is Ganwalho lake in A area and Bunamho lake in B area. Total birds surveyed four times in 2001 at the A area are 105,580 of 11 orders, 28 families, 89 species. Among them, resident species were 21 species including Pica pica. Twenty species including Cuculus canorus were summer migrants, and 30 species including Platalea leucorodia were winter migrants. Seventeen species including Limosa limosa were occasionally species. And Rostratula benghalensis was an unconfirmed species. Species diversity index (H') was 0.72; species equally common index (e/sup H'/) was 2.06. In January, maximum observed 102,121 individuals. However in July 52 species were observed most variously. There were total 81,152 birds observed with 11 orders, 22 families, and 71 species at the B area. Fifteen species including Falco tinnumculus were resident species. Summer migrants were 18 species including Ixobychus sinensis. Winter migrants were 25 species including Ciconia boyciana. Thirteen species including Tringa glareola were occasionally species. Species diversity index (H') was 0.281; species equally common index (e/sup H'/) was 1.325. In January, maximum observed 78,433 individuals. However in Silly 42 species were observed most variously.

• Journal of Plant Biology
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• 제16권1_2호
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• pp.1-5
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• 1973

Six young trees of Alnus tinctoria grown in isolation, each having different growing stage, were selected and the surface area of their roots, stems and leaves was determined. Each of the roots of more than 0.2mm in diameter and stems was cut at intervals of 10cm and their surface area was calculated with 2$\pi$rl from the average diameter (2r) of both sections (upper and lower) by making cylindrical estimation of the cut pieces. The leaf area measured was only one side area, and the volume of cut piece and amount of dry matter of each organ were also measured. The percentage to the surface area of the whole plant body by each organ was 4-12% in root, 7-9% in stem and 69-89% in leaf, respectively. There was relatively a little individual difference. However, the surface area ratios of root and stem showed a slightly increasing tendency while that of leaf decreasing according to the growing stage. The ratio of sum leaf area index (LAIi) was 2.3-4.0$m^2$/$m^2$-and that of the surface area index(SaIi) was 0.16-0.33$m^2$/$m^2$, respectively. It has been known that the stem surface area(SAI) to the leaf area index(LAI) is within the range of 31-53%, but the SAIi is within the range of 8-11% of the LAIi.

• 한국환경생태학회지
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• 제18권2호
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• pp.158-166
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• 2004

자연생태계의 보전을 위한 지역구분을 위하여 백두대간(남덕유산-소사고개) 구간을 조사한 식생조사 자료를 바탕으로 식생의 보전가치를 식생지수라는 것으로 수치화 하는 방법을 제시해 보고자 한다. 식생지수는 생물다양성, 임분의 보전가치, 환경의 청정성, 임분의 역사성, 입지의 생산성 등을 바탕으로 수치화 하였다. 식생지수는 백두대간 관리범위 설정에 이용될 수 있을 것이라 사료된다. 식생지수 I의 경우 총 66개의 조사지 중에서 8개 지역 12.1%가 핵심지역에 속하고, 21개 지역 31.8%, 37개 지역 56.1%가 각각 완충지역과 전이지역에 속하는 것으로 나타났다. 식생지수II의 경우 28개 지역 41.9%가 핵심지역에 속하고, 19개 지역 28.8%, 19개 지역 28.8%가 각각 완충지역과 전이지역에 속하는 것으로 나타났다.

• 환경생물
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• 제36권4호
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• pp.672-679
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• 2018

본 연구는 MaxEnt 모형을 활용하여 가는털비름의 잠재서식지를 예측하고, 예측된 잠재서식지와 밭면적을 활용하여 가는털비름의 잡초로서의 부정적 영향에 대한 위험도 지수를 예측하기 위하여 수행되었다. 가는털비름의 분포 예측을 위하여 MaxEnt 모형을 구축하기 위하여 남한 전국의 254지점의 분포 자료와 6개의 생물 기후 인자를 활용하였다. 밭농업에 대한 두가지 방법의 위험도 평가를 수행하였고 격자 위험도 지수(raster risk index)는 $1km^2$ 격자별로 잠재 서식지 분포 확률과 밭면적의 비율을 서로 곱하여 나타냈다. 지역 위험도 지수(regional risk index)는 잠재 서식지 분포 확률의 평균과 전체 밭 면적 중 지방자치단체의 실제 밭면적의 비율을 곱하여 산출하였다. MaxEnt모형으로 예측된 가는털비름의 잠재서식지는 실제서식지와 유사하게 나타났으며 모델의 AUC 값 또한 0.711로 좋은 설명력을 지니는 것으로 분석되었다. 잠재서식지 비율이 가장 높게 나타난 지역은 광주광역시였고 격자 위험도 지수가 가장 높게 나타난 지역은 제주도였다. 지역 위험도 지수가 가장 높게 나타난 지역은 경상북도였다. 잠재 서식지 비율과 위험도 지수의 서로 다른 순위는 외래식물의 위험성을 예측할 때 잠재 서식지 비율만을 활용하여 외래식물의 위험성을 예측하는 것보다 외래식물이 부정적 영향을 주는 대상과 결합된 위험도 지수의 필요성을 제시한다. 또한 격자 위험도 지수, 지역 위험도 지수의 서로 다른 순위는 분석의 필요성에 따라서 다양한 평가 기법이 개발될 필요성을 보여준다.

• Journal of Forest and Environmental Science
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• 제27권1호
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• pp.17-22
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• 2011

Based upon the vegetation data of woody plants by plot sampling method in the natural deciduous forest of Mt. Jeombong, the study was carried out to examine importance value, rank abundance curve, and species abundance curve, and comparatively evaluate seven different species diversity indices for Shannon-Wiener index, Simpson index, McIntosh index, Log series, Margalef index, Berger-Parker index, and species richness, according to topographic positions. The minimal area which meant only few more species were increased was 3.48 ha in total. The dominant species of valley were Carpinus cordata, Acer pseudo-sieboldianum, Quercus mongolica, Acer mono, and Abies holophylla, and the dominant species of mid-slope were Quercus mongolica, Acer pseudo-sieboldianum, Carpinus cordata, Tilia amurensis, and Fraxinus rhynchophylla. Moreover, the dominant species of ridge were Quercus mongolica, Acer pseudo-sieboldianum, Tilia amurensis, Fraxinus rhynchophylla, and Acer mono. According to rank abundance curve and species abundance curve, species evenness was also low. All of Log series, species richness, Margalef, and Shannon-Wiener index discriminated that valley had the highest diversity, and ridge had the lowest diversity; but, Simpson index, McIntosh index, and Berger-Parker index represented that mid-slope had the highest diversity, and ridge had the lowest diversity. Uniquely, in Berger-Parker index, mid-slope was the higher value than total.

• 한방비만학회지
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• 제6권1호
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• pp.61-67
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• 2006

Objectives : The purpose of this study was to determine what is useful index of abdominal visceral fat area among Korean obese adolescents. Methods : 35 obese adolescents who had visited Kirin Oriental Hospital from August 2004 to May 2006 were included in the study. Weight, height, waist and hip circumferences were measured. Abdominal visceral fat areas at L4-5 level were measured by computed tomography. The subjects were divided into two groups, according to sex. In each group, we investigated the correlation among waist circumference, waist/hip ratio, waist/height ratio, obesity degree and abdominal visceral fat area and evaluated that which one of these kinds of indices is the most useful predictor for visceral fat area in Korean obese adolescents. Results : There were significant correlation between waist circumference, waist/hip ratio, waist/height ratio and obesity index in both group. In boys waist/hip ratio had correlation with abdominal visceral fat area and in girls obesity index had significant correlation with abdominal visceral fat area. Conclusions : Our study suggests that waist/hip ratio in boys, obesity degree in girls can be a relatively good parameter for predicting abdominal visceral fat area.