• Composites Research
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• v.21 no.6
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• pp.23-30
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• 2008

In this paper, the effect of the natural aging on the strength distribution and structural service life of a Filament Wound (FW) composite pressure vessel was studied. The fiber failure strain, which is varied significantly, was considered as the design random variable and the strength analysis was carried out by probabilistic numerical approach. The progressive failure analysis technique and the First Order Reliability Method (FORM) were embedded in this numerical model. As the calculation results, the probability of failure was obtained for each aging time steps and it is found that the strength degradation in FW composite pressure vessel, due to the natural aging, appears within 10 year-aging-time. As an example of the life prediction under natural aging using arbitrary laminated model, the service lifetime of 13 years was predicted based on the probability of failure of 2.5% and the design pressure of 3,250 psi.

• Journal of Internet Computing and Services
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• v.24 no.2
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• pp.19-26
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• 2023

Humans have adapted and evolved to natural light. However, as humans stay in indoor longer in modern times, the problem of biorhythm disturbance has been induced. To solve this problem, research is being conducted on lighting that reproduces the correlated color temperature(CCT) of natural light that varies from sunrise to sunset. In order to reproduce the CCT of natural light, multiple LED light sources with different CCTs are used to produce lighting, and then a control index DB is constructed by measuring and collecting the light characteristics of the combination of input currents for each light source in hundreds to thousands of steps, and then using it to control the lighting through the light characteristic matching method. The problem with this control method is that the more detailed the steps of the combination of input currents, the more time and economic costs are incurred. In this paper, an LED lighting control method that applies interpolation and combination calculation based on the minimum spectral power distribution information for each light source is proposed to reproduce the CCT of natural light. First, five minimum SPD information for each channel was measured and collected for the LED lighting, which consisted of light source channels with different CCTs and implemented input current control function of a 256-steps for each channel. Interpolation calculation was performed to generate SPD of 256 steps for each channel for the minimum SPD information, and SPD for all control combinations of LED lighting was generated through combination calculation of SPD for each channel. Illuminance and CCT were calculated through the generated SPD, a control index DB was constructed, and the CCT of natural light was reproduced through a matching technique. In the performance evaluation, the CCT for natural light was provided within the range of an average error rate of 0.18% while meeting the recommended indoor illumination standard.

• Korean Journal of Remote Sensing
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• v.33 no.6_2
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• pp.1119-1137
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• 2017

This study assessed the water provisioning and climate mitigation ecosystem services of the urban forest in Seoul and Gyeonggi-do. The ecosystem service assessment is conducted based on natural function, natural function and population, and natural function and the beneficiary of the ecosystem service. Then, the impact of climate change on ecosystem services is analyzed to figure out the sensitivity of the impact on the beneficiary when the natural function of forest destroys under climate change. Gyeonggi-do has higher function-based water provisioning ecosystem service than Seoul. And population-based water provisioning ecosystem service appears to be higher in the densely populated area. On the other hand, beneficiary-based water provisioning ecosystem service by applying both natural water supply function and beneficiary distribution appears different with the result of population-based water provisioning service assessment. In other words, regions with high beneficiary population show higher ecosystem service than those with a low beneficiary population even though they have the same water storage function. In addition, climate change has a negative impact on the water provisioning ecosystem service. Under climate change, water provisioning service is expected to decrease by 26%. For climate mitigation service, regions close to the forest seem to have a low temperature, which indicates their high climate mitigation service. The center of the city with high beneficiary population shows high beneficiary-based ecosystem service. The climate change impacts the forest growth to decrease which affect the beneficiary-based climate mitigation ecosystem service to decrease by 33%. From this study, we conclude that beneficiary-based function and ecosystem service assessment is needed as well as the supply-based classification of forest function suggested by Korea Forest Service. In addition, we suggest that not only supply-based function classification and ecosystem service assessment but also beneficiary-based function classification and ecosystem service assessment is needed for managing the urban forest, which has been destroyed by climate change. This will contribute to revaluing cases where a forest with low natural function but high beneficiary-based ecosystem service, which is not considered under the current forest function-based assessment system. Moreover, this could assist in developing a suitable management plan for the urban forest.

• Journal of The Geomorphological Association of Korea
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• v.21 no.4
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• pp.53-67
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• 2014

This study aims to develop and operate education program for the region-focused field study on the physical geography for the students to understand their community places in the geography classes of elementary and, secondary schools and college. The theme of the program is understanding the geomorphic structures and processes including river channel, wetland, levee, terrace, sand and gravel bar and alluvial island, floodplain and irrigation system in Miho river basin, Chuncheong Province of Central Korea. For the study of regional geography as their community, the field education is focused on relations of landform to everyday life, though different levels in learning achievement according to each school classes. But, the purpose of the field education is, same at all classes, for student to analyze and understand the geomorphic effects on the place of everyday life in geography education.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.165-173
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• 2020

The activity of living microorganism directly or indirectly affects to the biomineralization in sediments and rocks that display the unique biotic structure. Minerals in the biotic structures showed unique properties and bypass the thermodynamic and kinetic barriers. Therefore, investigations on the biotically induced microstructure is essential to identify the new mineral formation mechanism by analyzing crystal structures and morphology at a nano-scale. The significant implication as well as advantages of using scanning electron microscopy to characterize the biotic structures were discussed in this paper for the examples of hydrothermal vent area microbial mat and deep-sea ferromanganese crust sample.

• Magazine of the Korean Society of Agricultural Engineers
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• v.53 no.1
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• pp.27-40
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• 2011

토양정보는 식량생산, 지속적인 토지이용 계획, 종다양성 평가에 사용되는 기본적인 자료이다. 우리나라 토양조사의 역사, 다양한 축척의 토양도 구축과 토양검정, 토양도와 토양검정 자료의 특성, 농업환경변동 모니터링을 통한 일반농경지 및 취약농경지 토양, 토양정보의 전산화에 따른 토양데이터베이스와 토양정보시스템 소개, 구축된 토양정보의 활용과 향후 방향에 대해 논하였다. 40여년 동안 수행되었던 국책 토양조사사업 결과 두 종류의 토양 데이터베이스가 구축되었는데, 다양한 축척의 토양도(1:250,000, 1:50,000, 1:25,000, 1:5,000)를 GIS DB로 전산화한 수치토양도 DB와 필지 단위로 조사된 화학성 위주의 토양분석 성적을 구축한 토양비옥도 DB이다. 흙토람(http://soil.rda.go.kr)에 서 제공하는 토양전자지도는 총 111종으로 토성, 경사, 지형, 모재, 배수등급, 자갈함량, 유효토심 등 토양 GIS 주제도 50종, 사과, 배, 마늘, 수박 등 작물 재배적지 61종이고, 82종의 토양통계 정보를 제공하고 있다. 최근 에는 친환경농업육성법 시행령에 따른 경작형태 및 오염원별 농경지 토양의 이화학성 및 농업용수 수질 조사 자료를 GIS DB로 구축하여 공간적인 분포와 시계열적인 변화를 분석하는 자료로 활용하고 있다. 농업환경변동 정보는 농업환경자원 인벤토리를 기반으로 일반농경지의 화학성과 농업용수의 수질, 토양 미생물 등의 공간적인 분포와 시간적인 변화 정보를 전문가 그룹에 제공하고 있다. 앞으로는 자연자원의 분포와 변동 정보를 바탕으로 보다 일반적이고 알기 쉽게 가공하여 일반인들에게 농업환경과 자연자원 보전의 중요성을 이해시키는 정보로 제공할 예정이다. 기존의 토양정보와 농업환경정보를 통합하여 컨텐츠를 보다 내실있게 하고 정보 수요자별로 손쉽게 목적에 맞는 접근을 할 수 있는 시스템을 만들어 사용자의 편의성을 강화시키는 방향으로 이끌어 가고자 한다.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1991.06a
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• pp.30-30
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• 1991

성대마비 이비인후과 영역에서는 비교적 빈번하게 관찰되는 질환으로 대부분은 미주신경과 그 분지인 반회신경이 경정맥공에서 후두까지의 주행중에 생긴 질환에 의하여 이차적으로 발생하거나, 드물게는 윤상갑상연골 관절의 고정에 의사여 발생하게 된다. 임상적인 진단은 간접후두경이나 화이버옵틱후두경 검사법에 의하여 간단하게 내려질 수 있으나, 그 발생원인은 다양하며, 임상적인 양상 및 그에 따른 치료 원칙도 다르게 나타난다. 이에 연자들은 1986년 1월 1일부터 1990년 12월 31일까지 5년간 국립의료원 이비인후과에 내원한 환자중 성대마비로 진단된 환자 61례에 대한 후향적 기록 분석에 의해 성별, 원인별, 측별, 성대의 위치, 및 그에 따른 치료방향에 대하여 비교 검토하여 다음과 같은 결과를 보였다. 1)성별은 남녀비가 3:2로 남자가 많았으며, 연령별 분포는 20대에서 70대까지 비교적 균등하였으나 50대(23.0%)에서 가장 많은 분포를 보였다. 2)원인으로는 원인불명이 16례(26.2%), 갑상선수술 8례(13.1%), 폐결핵과 기관내삽관후 각각 6례(9.8%), 폐암 5례(8.2%) 순이었다. 3)마비된 성대의 측별 분포는 편측성이 51례(83.6%), 양측성이 10례(16.4%)이며, 편측성중 좌측이 37례(60.6%)로 가장 많았다. 마비된 성대의 위치는 부정주위가 33례(54%)로 가장 많았다. 4)즉 증상은 단지 애성만 있었던 례가 31례(50.8%), 호흡곤란 혹은 기도흡인등을 동반한 애성이나, 애성을 동반하지 않은 례도 있었다(3례). 증상 발현후 병원 내원까지 기간은 2개월이내가 가장 많았다. 5)16례에서 수술적 처치가 시행되었거나(9례), 혹은 자연치유가 관찰되었는데(7례) 편측성마비때 갑상연골성형술 2례, 양측 마비때 후두외접근법에 의한 피열연골절제술 4례, 레이저를 이용한 피열연골절제술 2례, 승모판 협착증에 의한 편측성 성대마비에서 개심술후 성대마비 회복 1례, 자연 치유는 7례에서 관찰되었으며 6례에서는 증상발현후 6개월이내에 회복되었다.

• Journal of Life Science
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• v.25 no.4
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• pp.369-375
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• 2015

Data on the spatial distribution of a plant population among administrative areas is useful for various purposes. In this study, I analyzed the spatial distribution of the geographical distances of Carex siderosticta at Mt. Geumjeong and Mt. Ahop in Korea. The aim was to test a spatial structure within two populations of C. siderosticta. Most natural plots of C. siderosticta are not uniformly distributed in the forest community; for example, uniform plots were aggregately distributed within a space of 6.0 m $\times$ 6.0 m. When the sampling plots were larger than 6.0 m $\times$ 12.0 m, the individuals of C. siderosticta were aggregately distributed. The neighboring patches of C. siderosticta were predominantly 7.5 m to 9.0 m apart, on average; however, if the natural populations were disturbed by human activities, the aggregation occurred in shorter distances than a scale of 9.0 m. Moran's I of C. siderosticta significantly differed from the expected value in only 16 of 40 cases (40%). In conclusion, the geographical distribution of C. siderosticta is not even, with varying degrees of size in the plots, while human activities give rise to density effects in the plots at both Mt. Geumjeong and Mt. Ahop in Korea.

• Korean Journal of Environmental Biology
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• v.25 no.2
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• pp.115-123
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• 2007

On the riparian zone of streams in the middle part of Korea, the distribution of naturalized plants was investigated. The species number and proportion of naturalized plants in each stream was increased from upstream to downstream of the stream and the highest proportion was observed at urban area of Jungryangcheon. A large number of naturalized plants has annual habit and European or North American origin. Highest similarity index of naturalized plants was observed between Hongcheongang and Naechoncheon. The percentage of herb plants showed positive relationship with that of naturalized plants in the steams, particularly high at the urban steam Jungryangcheon.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.5
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• pp.587-594
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• 2019

This study experimentally investigated the effects of high and low densities of vegetation patches on the flow characteristics in a stream-scale outdoor experimental channel with rooted willows. Stream-scale experiments on vegetated flows were carried out for an emergent condition of vegetation. Vegetation patches were arranged by alternate bar formation and the flows in vegetated and non-vegetated sections were compared. Three-dimensional flow structure was measured by ADV (Acoustic Doppler Velocimeter) and the vertical distributions of longitudinal velocity were mainly analyzed from the measurements at various points. Flow velocities show different patterns depending on the density of vegetation patches. The difference in flow velocity between in the vegetated and non-vegetated sections appear to large in the dense patches and the flow becomes complicated at the downstream edge of the patch. Despite the upstream flow disturbed by the first patch, the flows over the second patch show the similar pattern.