• 한국자원식물학회지
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• 제28권4호
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• pp.400-410
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• 2015

Juniperus chinensis (Cupressaceae) is a valuable woody plant resource, but this rare plant is only distributed in restricted regions in Korea. In this study, we surveyed the geographic distribution regions, variation of sex ratio and the dynamics of natural populations of J. chinensis. in order to establish conservation strategies for the sustainable conservation of this important resource tree. The 17 natural populations of J. chinensis are restrictively distributed in the shore cliffs of (1) Ulleungdo island, (2) Gyeongju-si to Gangneung-si of the eastern coast, the riverside cliff along (3) Donggang-river of Jungsun-gun and Pyeongchang-gun and (4) branch of Nakdonggang-river in Uiseong-gun. The populations in Ulleungdo island showed continuous population distribution of over 200 individuals, but populations in other regions had discontinuous population distribution of under 200. The population of J. chinensis surveyed in Korea was estimated in ca. 3,200 individuals. The sex ratio (male/female) among populations of J. chinensis was diverse with variation from 0.46~1.67 range, but showed no significance. The sex ratio of the total individuals by species level was 0.74, and the percentage of female tree was significantly higher than the male. The results of dynamics analysis within population among regions showed that seedlings and saplings of J. chinensis in three regions surveyed were continuously regenerating. The distribution of DBH class showed a stable population structure of inverse J shape graph, but fragmentation and decrease in populations because of invading broad-leaved shrubs and trees from the surroundings were concerned. Further studies, and in situ and ex situ conservation strategies for the sustainable conservation on natural populations of this rare resources woody plant, J. chinensis in Korea are recommended.

• Journal of Radiation Protection and Research
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• 제46권4호
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• pp.170-177
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• 2021

Background: The International Commission on Radiological Protection is preparing to provide reference dose coefficients for environmental radioiodine intake based on newly developed age-specific biokinetic models. However, the biokinetics of iodine has been reported to be strongly dependent on the dietary intake of stable iodine; for example, the thyroidal uptake of iodine may be substantially lower in iodine-rich regions than in iodine-deficient regions. Therefore, this study attempted to establish a system of age-specific thyroid dose estimation for South Koreans, whose daily iodine intakes are significantly higher than that of the world population. Materials and Methods: Korean age-specific biokinetic parameters and thyroid masses were derived based on the previously developed Korean adult model and the Korean anatomical reference data for adults, respectively. This study complied with the principles used in the development of age-specific biokinetic models for world population and used the ratios of baseline values for each age group relative to the value for adults to derive age-specific values. Results and Discussion: Biokinetic model predictions based on the Korean age-specific parameters showed significant differences in iodine behaviors in the body compared to those predicted using the model for the world population. In particular, the Korean age-specific thyroid dose coefficients for ¹²⁹I and ¹³¹I were considerably lower than those calculated for the world population (25%-76% of the values for the world population). Conclusion: These differences stress the need for Korean-specific internal dose assessments for infants and children, which can be achieved by using the data calculated in this study.

• 한국환경생태학회지
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• 제30권4호
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• pp.658-675
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• 2016

분포지의 환경특성, 개체군구조, 생태적지위, 생활사 특성 그리고 개체군 통계적 연구는 효과적인 보전을 위해 필수적인 정보이다. 우리는 12년간의 분포조사를 통해 총 37개의 분포지를 확인하였고 그중 12개 지역에 있는 25개의 집단을 대상으로 생육지의 환경과 개체군 구조를 조사하였다. 강원도 평창군 대관령면의 8개 집단을 대상으로 4년간에 걸친 개체군동태를 조사하였다. 4년간의 재배실험과 화분매개곤충의 영향을 관찰하였다. 조사결과 산작약은 비교적 넓은 식생환경에 걸쳐 분포하였다. 조사가 이루어진 25개 집단의 개체군 구조는 비교적 안정적인 집단과 극단적으로 성체만이 존재하는 집단 등 상당한 차이를 나타내었다. 조사기간 동안 상층식생에 생성된 숲 틈이 개체군 동태에 영향을 미치는 요인으로는 추정되었다. 재배실험에서 유묘는 토양의 유기물이 상대적으로 적은 곳에서 잘 성장하였다. 화분매개곤충의 방문이 결실한 종자의 수와 결실률에서 높게 나타나는 경향이 있었다. 결론적으로, 산작약의 분포는 환경적 요인과 더불어 분포에 관여하는 다른 요인의 연구가 필요하며 그 중에서 종자의 운반체에 대한 연구의 필요성을 제안하였다. 현재의 산작약 개체군은 과거 급격한 분포지의 감소 이후 확대되는 과정으로 평가되었다. 멸종위기야생식물인 산작약의 효과적인 보전을 위해서는 시공간적 확장을 통한 종에 대한 이해와 이를 바탕으로 한 생태계의 건강성 유지를 제안하였다.

• Journal of the Korean Statistical Society
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• 제32권4호
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• pp.359-371
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• 2003

We consider the probability that the total population of a stable Jackson network reaches a given large value. By using the fluid limit of the reversed network, we derive new upper and lower bounds on this probability, which are sharper than those in Glasserman and Kou (1995). In particular, the improved lower bound is useful for analyzing the performance of an importance sampling estimator for the overflow probability in Jackson tandem networks. Bounds on the expected time to overflow are also obtained.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.501-503
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• 2001

Electric power consumption is highly increasing as the social trend requiring comfortable life, the population in a big city and the industrial development. Therefore it has become to be very important to supply the stable high-quality power. As these trend, the underground power transmission facility is highly increasing in the center of a city. As the proportion to increase facility in tunnel, the fire prevention measures of the underground transmission line become very important.

• 환경생물
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• 제36권1호
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• pp.1-10
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• 2018

논 생태계는 일부 생물의 개체군 유지를 위한 중요한 서식지로서 역할을 하고 있다. 이러한 논 생태계를 대상으로 농법에 따른 수생태계에 미치는 영향에 대한 연구는 미비하다. 따라서 친환경농법 및 관행농법과 같은 재배 방식의 차이는 생물서식지에 다양한 영향을 미치기 때문에 두 농법에 따른 미꾸리 개체군의 서식특성 및 성장도의 차이를 확인하였다. 조사기간은 2015년 5월부터 9월까지였고, 대호 간척농지를 대상지로 하였다. 영농방법에 따라 개체수, 미꾸리 개체군 분포, 전장-체중 상관도 및 비만도 지수 비교, 미꾸리 개체군의 전장크기 등을 비교하였다. 미꾸리 개체군의 크기는 친환경 논에서 월등히 큰 것을 확인할 수 있었다. 또한 연령대 분포는 친환경 논이 다양한 연령층의 미꾸리가 서식하는 것으로 나타났으나 관행 논은 Age $0^+$ (28~51 mm)의 개체들이 대부분 성장하지 못하고 사멸하며, 일부 내성을 지니는 개체만이 성장하는 것으로 판단된다. 특히 5월에 관행 논과 친환경 논에서 거의 비슷한 미꾸리 개체수를 보이는 것은 로터리 및 경운에 의해서 토양의 얕은 깊이에 서식하는 미꾸리가 폐사된 것으로 판단되어 무경운이 미꾸리 개체군 유지에 큰 기여를 할 것으로 판단된다. 친환경 논의 미꾸리는 먹이섭식 및 영양상태가 안정적인 것으로 나타났다. 또한 6월에 관행 논 및 친환경 논에서 성장도 및 비만도가 낮은 것에 대하여는 추가적인 조사연구가 필요할 것으로 판단된다. 관행 논에서 미꾸리 개체군의 개체수 회복 및 연령대 회복을 위해서는 농약과 같은 화학물질 사용을 제한해야할 것으로 사료되며, 또한 관행농법보다 친환경농법으로 재배할 경우 미꾸리 개체의 유지 및 회복에 큰 기여를 할 것으로 기대된다.

• 농촌지도와개발
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• 제8권2호
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• pp.263-271
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• 2001

The purpose of this study were to review the current problems of rural welfare and to suggest desirable direction for development of welfare in rural Korea. Specific objectives of the study were to investigate the current status and problems of rural welfare and to search for the desirable directions for rural welfare development in Korea. The major findings of the study were as follows ; 1. Some of the current problems of rural welfare were; (1) difficulty in getting a job for stable income, (2) seriousness of medical care and aging of rural population, (3) decrease in number of rural school children and unfavorable educational environment, and (4) insufficiency in facility, manpower and program for recreation and cultural activities in rural area. 2. Problems of rural welfare were not independent in rural Korea, but the most of the problems were interrelated to each other. Integrated and comprehensive approach would be necessary to solve the problems of rural welfare. 3. Clean environment, stable and rewarding life, pride and self esteem of rural occupation should be the goals of better integrated rural welfare development, and healthfulness and quality of life should be ensured in rural society. 4. Urban oriented national policy based on urban centered political power was one of the causes of under development in rural welfare by creating rapid decrease in rural population and aging. Various problems in economic, educational, cultural and medical aspects of rural society should be solved. Further research on rural welfare should be conducted to increase and to strengthen rural welfare development in Korea.

• Journal of Forest and Environmental Science
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• 제36권1호
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• pp.37-46
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• 2020

Vegetation carbon sequestration and regeneration are the two major parameters of forest research. In this study, we analyzed the vegetation carbon stock and regeneration of community-managed pine plantation of Kathmandu, central Nepal. Vegetation data were collected from 40 circular plots of 10 m radius (for the tree) and 1m radius (for seedling) applying a stratified random sampling and nested quadrat method. The carbon stock was estimated by Chave allometric model and estimated carbon stock was converted into CO₂ equivalents. Density-diameter (d-d) curve was also prepared to check the regeneration status and stability of the plantation. A d-d curve indicates the good regeneration status of the forest with a stable population in each size class. Diversity of trees was very low, only two tree species Pinus roxburghii and Eucalyptus citriodora occurred in the sample plots. Pine was the dominant tree in terms of density, basal area, biomass, carbon stock and CO₂ stock than the eucalyptus. The basal area, carbon stock and CO₂ stock of forest was 33±1.0 ㎡ ha^-1, 108±5.0 Mg ha^-1 and 394±18 Mg ha^-1, respectively. Seedling and tree density of the plantation was 4,965 ha^-1 and 339 ha^-1 respectively. The forest carbon stock showed a positive relationship with biomass, tree diameter, height and basal area but no relationship with tree density. Canopy cover and tree diameter have a negative effect on seedling density and regeneration. In conclusion, the community forest has a stable population in each size class, sequestering a significant amount of carbon and CO₂ emitted from densely populated Kathmandu metro city as the forest biomass hence have a potentiality to mitigate the global climate change.

• 지적과 국토정보
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• 제49권1호
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• pp.123-144
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• 2019

본 연구의 목적은 최근 감소하고 있는 우리나라 인구 증감 현상에 대해 지역 및 주택 시장 특성을 통해 인구 증감 요인을 파악하는 데 있다. 전국 85개시의 최근 5년간 지역별 인구 증가율 평균을 종속 변수로 하고 최근 5년 간 지역 및 주택 시장 특성 요인 변수들의 평균을 독립변수로 하는 다중회귀를 분석 방법으로 활용하였다. 분석결과, 최근 5년 간 지역별 인구 증가율에 유의미한 영향을 미친 지역 및 주택 시장 변수는 출산율, 고용률, 생산 가능 인구 증가율, 아파트 비율, 분양권 전매 비율, 아파트 거래 회전 증가율, 천인당 사업체 수 등이었으며 최근 5년 간 지역별 인구가 증가한 지역으로는 서울과 광역시를 제외한 수도권 일부와 비수도권 지방 중 공공 기관 이전(혁신도시), 택지개발 등이 있는 지역들이었다. 따라서 분석 결과를 종합할 때 지역의 인구를 증가시키기 위해서는 안정된 일자리와 그와 연계된 적절한 주택 공급이 전제 되어야 함을 의미한다. 본 연구의 이러한 연구 결과는 인구감소를 겪고 있는 지방 중소도시 등 수도권 이외 지역 등을 위한 정부 차원에서 지역 균형발전을 위한 정책적 시사점을 제시하였다는 점에 연구의 의의가 있다고 할 수 있다.

• Journal of Ecology and Environment
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• 제38권2호
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• pp.185-193
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• 2015

A dramatic decline in the abundance of the scaled quail (Callipepla squamata) has been observed across most of its geographic range. In order to evaluate the influence of land cover patterns and their changes on scaled quail abundance, we examined landscape patterns and their changes from the 1970s to the1990s in two large ecoregions with contrasting population trends: (1) the Rolling Plains ecoregion with a significantly decreased scaled quail population and (2) the South Texas Plains ecoregion with a relatively stable scaled quail population. The National Land Cover Database (NLCD) and the U.S. Geological Survey's (USGS) Land Use/Land Cover data were used to quantify landscape patterns and their changes based on 80 randomly located $20{\times}20km^2$ windows in each of the ecoregions. We found that landscapes in the Rolling Plains and the South Texas Plains were considerably different in composition and spatial characteristics related to scaled quail habitats. The landscapes in the South Texas Plains had significantly more shrubland and less grassland-herbaceous rangeland; and except for shrublands, they were more fragmented, with greater interspersion among land cover classes. Correlation analysis between the landscape metrics and the quail-abundance-survey data showed that shrublands appeared to be more important for scaled quail in the South Texas Plains, while grassland-herbaceous rangelands and pasture-croplands were essential to scaled quail habitats in the Rolling Plains. The decrease in the amount of grassland-herbaceous rangeland and spatial aggregation of pasture-croplands has likely contributed to the population decline of scaled quails in the Rolling Plains ecoregion.