• 제목/요약/키워드: Deep Soil

검색결과 704건 처리시간 0.023초

우리나라의 주요가뭄해석을 위한 각종 가뭄지수의 적용 (An Application of Various Drought Indices for Major Drought Analysis in Korea)

  • 이재준;이창훈
    • 한국방재학회 논문집
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    • 제5권4호
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    • pp.59-69
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    • 2005
  • 가뭄을 미리 발견하고 감시하는 것은 어려우나, 가뭄지수를 이용하면 가뭄의 파악이 용이하다. PDSI는 통상적으로 가장 널리 이용되나 운영상 제한성을 가지고 있다. 최근 들어 가뭄을 인지하고 감시하는 능력이 향상된 SPI가 개발되었으며, 이는 기존의 지수들에 비해 모든 시간간격에 적용이 가능하고 간단하게 이용이 가능하다. KBDI는 상부토양층의 누적수분부족량을 산출함에 있어서 증발산과 강수량의 순영향을 나타내는 지수로 정의하였다. 본 연구에서는 PDSI, SPI, KBDI를 이용하여 산정된 가뭄지수의 상호비교 연구를 통하여 표준 가뭄지수를 제안하고자 한다. 이를 위하여 우리나라 8개 수계의 30년 이상의 기상자료를 보유한 기상청 강우관측소 자료를 이용하였다. 그 결과 PDSI는 누적되는 강우의 부족으로 가뭄심도를 나타내는 데 유리하고, SPI와 KBDI는 단기간 강우부족을 나타내는데 유리한 것으로 나타났다.

Complexity Analysis of the Viking Labeled Release Experiments

  • Bianciardi, Giorgio;Miller, Joseph D.;Straat, Patricia Ann;Levin, Gilbert V.
    • International Journal of Aeronautical and Space Sciences
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    • 제13권1호
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    • pp.14-26
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    • 2012
  • The only extraterrestrial life detection experiments ever conducted were the three which were components of the 1976 Viking Mission to Mars. Of these, only the Labeled Release experiment obtained a clearly positive response. In this experiment $^{14}C$ radiolabeled nutrient was added to the Mars soil samples. Active soils exhibited rapid, substantial gas release. The gas was probably $CO_2$ and, possibly, other radiocarbon-containing gases. We have applied complexity analysis to the Viking LR data. Measures of mathematical complexity permit deep analysis of data structure along continua including signal vs. noise, entropy vs.negentropy, periodicity vs. aperiodicity, order vs. disorder etc. We have employed seven complexity variables, all derived from LR data, to show that Viking LR active responses can be distinguished from controls via cluster analysis and other multivariate techniques. Furthermore, Martian LR active response data cluster with known biological time series while the control data cluster with purely physical measures. We conclude that the complexity pattern seen in active experiments strongly suggests biology while the different pattern in the control responses is more likely to be non-biological. Control responses that exhibit relatively low initial order rapidly devolve into near-random noise, while the active experiments exhibit higher initial order which decays only slowly. This suggests a robust biological response. These analyses support the interpretation that the Viking LR experiment did detect extant microbial life on Mars.

연직배수재의 통수능력평가를 위한 실험적 연구 (An experimental study on the evaluation of discharge capacity for vertical plastic drain board)

  • Kim, Joonseok;Lee, Kangil
    • 한국재난정보학회 논문집
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    • 제13권4호
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    • pp.483-490
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    • 2017
  • 최근 경제성장과 함께 산업용, 주거용 토지의 요구가 증대되고 있으나 좋은 지반조건으로 개발된 토지를 얻기가 어려워지고 있다. 샌드드레인, 모래다짐말뚝, 팩드레인, 프라스틱보드드레인(PBD)등 다양한 연직배수기술이 연약지반의 경제적 개발을 가능하게 하고 있다. 연직배수에서는 통수능력이 중요한 요소이다. 그러나, 현장조건에서는 토질조건, 상재하중 등 다양한 조건에 의하여 통수능력이 변화된다. 본 논문에서는 이중코어형 PBD, 대심도형 PBD, X형 PBD, 일반형 PBD등 4가지 다른 형태의 PBD에 대하여 통수능 시험이 수행되었다. 상재하중과 동수경사에 따른 통수능 특성을 분석하였다. 본 연구에서는 이중코어형의 통수능력이 가장 우수하였다.

Microbial Rhodopsins: Genome-mining, Diversity, and Structure/Function

  • Jung, Kwang-Hwan;Vishwa Trivedi;Yang, Chii-Shen;Oleg A. Sineschekov;Elena N. Spudich;John L. Spudich
    • Journal of Photoscience
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    • 제9권3호
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    • pp.45-48
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    • 2002
  • Microbial rhodopsins, photoactive 7-transmembrane helix proteins that use retinal as their chromophore, were observed initially in the Archaea and appeared to be restricted to extreme halophilic environments. Our understanding of the abundance and diversity of this family has been radically transformed by findings over the past three years. Genome sequencing of cultivated microbes as well as environmental genomics have unexpectedly revealed archaeal rhodopsin homologs in the other two domains of life as well, namely Bacteria and Eucarya. Organisms containing these homologs inhabit such diverse environments as salt flats, soil, freshwater, and surface and deep ocean waters, and they comprise a broad phylogenetic range of microbial life, including haloarchaea, proteobacteria, cyanobacteria, fungi, and algae. Analysis of the new microbial rhodopsins and their expression and structural and functional characterization reveal that they fulfill both ion transport and sensory functions in various organisms, and use a variety of signaling mechanisms. We have obtained the first crystallographic structure for a photosensory member of this family, the phototaxis receptor sensory rhodopsin II (SRII, also known as phoborhodopsin) that mediates blue-light avoidance by the haloarchaeon Natronobacterium pharaonis. The structure obtained from x-ray diffraction of 3D crystals prepared in a cubic lipid phase reveals key features responsible for its spectral tuning and its sensory function. The mechanism of SRII signaling fits a unified model for transport and signaling in this widespread family of phototransducers.

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Annual and spatial variabilities in the acorn production of Quercus mongolica

  • Noh, Jaesang;Kim, Youngjin;Lee, Jongsung;Cho, Soyeon;Choung, Yeonsook
    • Journal of Ecology and Environment
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    • 제44권4호
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    • pp.229-240
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    • 2020
  • Background: Genus Quercus is a successful group that has occupied the largest area of forest around the world including South Korea. The acorns are an important food source for both wild animals and humans. Although the reproductive characteristics of this genus are highly variable, it had been rarely studied in South Korea. Therefore, in Seoraksan and Odaesan National Parks (i) we measured the acorn production of Quercus mongolica, an overwhelmingly dominant species in South Korea, for 3 years (2017-2019), (ii) evaluated the spatial-temporal variation of acorn production, and (iii) analyzed the effects of oak- and site-related variables on the acorn production. Results: The annual acorn production of Q. mongolica increased 36 times from 1.2 g m-2 in 2017 to 43.2 g m-2 in 2018, and decreased to 16.7 g m-2 in 2019, resulting in an annual coefficient of variation of 104%. The coefficient of spatial variation was high and reached a maximum of 142%, and the tree size was the greatest influencing factor. That is, with an increase in tree size, acorn production increased significantly (2018 F = 16.3, p < 0.001; 2019 F = 8.2, p < 0.01). Elevation and slope also significantly affected the production in 2019. However, since elevation and tree size showed a positive correlation (r = 0.517, p < 0.001), the increase in acorn production with increasing elevation was possibly due to the effect of tree size. The acorn production of Odaesan for 3 years was 2.2 times greater than that of Seoraksan. This was presumed that there are more distribution of thick oak trees and more favorable site conditions such as deep soil A-layer depth, high organic matter, and slower slopes. Conclusion: As reported for other species of the genus Quercus, the acorn production of Q. mongolica showed large spatial and annual variations. The temporal variability was presumed to be a weather-influenced masting, while the spatial variability was mainly caused by oak tree size.

수치해석을 통한 지하철 구조물 인접 굴착에 따른 보강공법 적용사례연구 (A Case Study on Reinforcement Method by Excavation Adjacent to the Subway Tunnel using Numerical Analysis)

  • 변요셉;정경식;천병식
    • 한국지반환경공학회 논문집
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    • 제12권9호
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    • pp.5-11
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    • 2011
  • 최근 들어 대규모 및 대심도 지반굴착공사가 증가하고 있으며, 굴착으로 인한 인접구조물들의 붕괴사례는 건설수요와 더불어 꾸준히 증가하고 있고, 특히 도심지 개발 및 불량한 조건에서의 지하철 구조물과 인접하여 진행되는 굴착으로 인해 발생될 수 있는 문제점이 많아지고 있는 실정이다. 이에 본 논문에서는 서울시 내에서 수행된 16개 현장에 대한 사례연구를 통해 적용된 지하굴착공법과 보강공법의 현황을 고찰하였다. 또한 대표 현장을 선택하여 안정성 분석을 실시하였고, 적용된 굴착공법 및 보강방안에 대해 검토하고 이에 따른 공법의 적정성에 대해 검토하였다. 그 결과 16개 현장의 지층 분포상태는 모두 상부로부터 매립층, 그 하부는 퇴적층, 풍화토, 풍화암, 연암층의 순으로 분포하고 있었다. 또한 중요 구조물에 인접하여 굴착공사를 진행할 경우 구조물의 위치 및 지층조건에 매우 큰 영향이 있는 것으로 나타났다. 또한 도심지 특성상 일반 가시설 공법을 적용하여 지하철구조물과 인접하여 굴착이 진행될 경우는 별도의 보강공법의 적용이 필요할 것으로 판단된다.

아쿠아포닉스의 생육 환경을 고려한 성장 측정 시스템의 설계 (A Design of Growth Measurement System Considering the Cultivation Environment of Aquaponics)

  • 이현섭;김진덕
    • 한국정보통신학회논문지
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    • 제27권1호
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    • pp.27-33
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    • 2023
  • 웰빙과 건강관리에 대한 관심 증가와 미세먼지로 인한 공기질의 악화, 다양한 토양 및 수질 오염으로 인해 친환경 식재료에 대한 요구가 급증하고 있다. 이와 같은 현상의 해결책으로 아쿠아포닉스가 대두되고 있다. 그러나 최적의 생육 환경을 도출하는 기법이 선행되어야 한다. 본 논문에서는 기존 아쿠아포닉스의 특성을 고려하는 지능형 식물 성장 측정 시스템을 설계하고자 한다. 특히, 지능형 아쿠아포닉스 생산관리 모듈 중 고성능의 처리 자원을 갖지 않는 생산 현장에 적합한 시스템 설계에 주안점을 두고, 균일한 생육환경을 제공하는 경우의 학습 데이터 및 판단 시스템을 위한 모듈 구성 방안을 제안하고자 한다.

SENTINEL-2 위성영상을 이용한 조림 특성 조사: 세미양오름를 통한 사례 연구 (Characterization of Tree Composition using Images from SENTINEL-2: A Case Study with Semiyang Oreum)

  • 정용석;윤성욱;허성;김윤석;안진현;한경덕
    • 한국환경과학회지
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    • 제31권9호
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    • pp.735-741
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    • 2022
  • Global warming affects forests and their ecology. Diversity in the forest is a buffer that reduces the damage due to global warming. Mixed forests are ecologically more valuable as versatile habitats and are effective in preventing landslides. In Korea, most forests were created by simple afforestation with trees of evergreen species. Typically, evergreen trees are shallow-rooted, and deciduous trees are deep-rooted. Mixed forest tree roots grip the soil effectively, which reduces the occurrence of landslides. Therefore, improving the distribution of tree types is essential to reduce damage due to global warming. For this improvement, the investigation of tree types of the forest is needed. However, determining the tree type distribution of forests that are spread over wide areas is labor-intensive and time-consuming. This study suggests effective methods for determining the distribution of tree types in a forest that is spread across a relatively wide area. Using normalized difference vegetation index and RGB images from unmanned aerial vehicles, each evergreen and deciduous tree, and grassland area can be distinguished. The distinguished image determines the distribution of tree type. This method is effective compared to directly determining the tree type distribution in the forest by the use of manpower. The data from these methods could be applied to plan a mixed forest or to prepare for future damage due to global warming.

수평지반반력계수와 점착력에 따른 지반변형계수 산정방법 연구 (A Study on the Method of Calculating the Deformation Coefficient According to the Horizontal Subgrade Reaction Modulus and Cohesion)

  • 전성재;정대석
    • 한국재난정보학회 논문집
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    • 제19권1호
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    • pp.31-43
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    • 2023
  • 연구목적: 본 연구에서는 탄소성해석과 수치해석의 차이점 분석과 해석 결과치의 유사한 경향을 도출하기 위한 설계지반정수 재산정 방법의 연구를 수행하였다. 연구방법: 얕은굴착과 깊은굴착에 따라 벽체변위가 같아지는 시점에서의 지반반력계수와 지반변형계수의 관계식을 유도하였다. 연구결과: 계측결과를 바탕으로 역해석을 진행하여 현장지반에 맞는 지반물성을 재산정하고 도출된 식과 문헌식을 이용하여 벽체변위에 대한 비교·검증한 결과 제안식이 가장 유사한 값을 나타내고 있었다. 결론: 제안식을 이용하면 설계시 실제와 가장 비슷한 지반물성치를 유추할 수 있어 실무에 도움이 될 것이다.

Experimental evaluation of back-to-back anchored walls by double-plates anchors

  • Amir, Najafizadeh;AmirAli, Zad
    • Geomechanics and Engineering
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    • 제31권6호
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    • pp.599-614
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    • 2022
  • One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.