• 한국농공학회논문집
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• 제61권6호
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• pp.31-40
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• 2019

In order to implement practical alternatives to proactively cope with the agricultural drought, the potential vulnerability of irrigation pumping stations to agricultural drought was quantitatively evaluated. Data for the 124 pumping stations which are correlatable to the three proxy variables, i.e. exposure, sensitivity, and adaptive capacity was collected by the Korea Rural Community Corporation, and then standardized considering distribution of each data set. Finally, the vulnerability index was calculated by multiplying the weights determined by the expert survey. The results showed that the vulnerability index ranged from 0.709 to 0.331 and the most vulnerable pumping stations such as Judam, Wongoo and Jinahn were mostly located in Gyeongbuk province likely because of the climatological characteristics with high temperature and low rainfall around this area. In addition, it was found that the adaptive capacity was a dominant factor comparing to exposure or sensitivity proxy variables in contributing to the vulnerability. It is therefore recommended that more practical alternatives should be employed to effectively reduce the vulnerability of an individual pumping station to agricultural drought. Furthermore, the corresponding data related to adaptive capacity should be systematically organized and managed at a field level to design reliable adaptation strategies.

• Journal of Information Science Theory and Practice
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• 제7권3호
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• pp.6-20
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• 2019

Learning analytics, or educational data mining, is an emerging field that applies data mining methods and tools for the exploitation of data coming from educational environments. Learning management systems, like Moodle, offer large amounts of data concerning students' activity, performance, behavior, and interaction with their peers and their tutors. The analysis of these data can be elaborated to make decisions that will assist stakeholders (students, faculty, and administration) to elevate the learning process in higher education. In this work, the power of Excel is exploited to analyze data in Moodle, utilizing an e-learning course developed for enhancing the information computer technology skills of school teachers in primary and secondary education in Greece. Moodle log files are appropriately manipulated in order to trace daily and weekly activity of the learners concerning distribution of access to resources, forum participation, and quizzes and assignments submission. Learners' activity was visualized for every hour of the day and for every day of the week. The visualization of access to every activity or resource during the course is also obtained. In this fashion teachers can schedule online synchronous lectures or discussions more effectively in order to maximize the learners' participation. Results depict the interest of learners for each structural component, their dedication to the course, their participation in the fora, and how it affects the submission of quizzes and assignments. Instructional designers may take advice and redesign the course according to the popularity of the educational material and learners' dedication. Moreover, the final grade of the learners is predicted according to their previous grades using multiple linear regression and sensitivity analysis. These outcomes can be suitably exploited in order for instructors to improve the design of their courses, faculty to alter their educational methodology, and administration to make decisions that will improve the educational services provided.

• 한국기후변화학회지
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• 제7권2호
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• pp.143-155
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• 2016

Present work aims to establish the countermeasure for the better maintenance and preservation of insular floristic diversity at the South Sea of Jeollanamdo Province, ROK, where unique ecosystems are under threat due to climate change, anthropogenic disturbance and habitat destruction. Numerous flora reports from 15 inhabited islands and 60 uninhabited islands as well as field survey data are collated for the compilation of floristic data base and island biogeographical analysis. Out of the 1,940 vascular plant species from 180 families occurring in studies areas, 30.1 percentage or 584 plant species are physiognomically belonging to arboreal plants. Average number of species at individual island is numbered about 222 species, but it varies from about 591 species at the inhabited islands to 129 species at the uninhabited islands. Only 0.15 percentage of species with high proportion above 0.9 in its relative occurrence rate occurs at 68 islands and it includes three species, such as Pinus thunbergii, Eurya japonica and Pteridium aquilinum var. latiusculum. However, about 68 percentage of plant species occurring in study area is confined their distribution to less than seven islands. Presence of high proportion of notable plants in small islands, i.e., 10 critically endangered species compared with 5.5 species in average, 9 endangered species (average 4.2 spp.) at Sonjookdo, and 7 critically endangered species, 8 endangered species at Sokomundo may due to existence of diverse geological and topographical environmental diversity as well as lower human population density and remoteness from the mainland. Since island is small in size and geographically isolated, minor environmental and ecological burdens can cause the critical damages to the diversity of flora and vegetation, urgent island biogeographical research is needed for the scientific conservation and management of island biodiversity.

• Earthquakes and Structures
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• 제20권1호
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• pp.71-86
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• 2021

This paper focuses on the development and assessment of the expected damage for the rocking response of rigid anchored blocks, with irregular geometry and non-uniform mass distribution, considering the site conditions and the seismicity of Mexico City. The non-linear behavior of the restrainers is incorporated to evaluate the pure tension and tension-shear failure mechanisms. A probabilistic framework is performed covering a wide range of block sizes, slenderness ratios and eccentricities using physics-based ground motion simulation. In order to incorporate the uncertainties related to the propagation of far-field earthquakes with a significant contribution to the seismic hazard at study sites, it was simulated a set of scenarios using a stochastic summation methods of small-earthquakes records, considered as Empirical Green's Function (EGFs). As Engineering Demand Parameter (EDP), the absolute value of the maximum block rotation normalized by the body slenderness, as a function of the peak ground acceleration (PGA) is adopted. The results show that anchorages are more efficient for blocks with slenderness ratio between two and three, while slenderness above four provide a better stability when they are not restrained. Besides, there is a range of peak intensities where anchored blocks located in soft soils are less vulnerable with respect to those located in firm soils. The procedure used in here allows to take decisions about risk, reliability and resilience assessment of different types of contents, and it is easily adaptable to other seismic environments.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.185-185
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• 2023

Agricultural water demand is considered as the major sector of water withdrawal due to irrigation. The majority part of the global agricultural field depends on various irrigation techniques. Therefore, a timely and sufficient supply of water is the most important requirement for agriculture. Irrigation is implemented in different ways in various land surface models, it can be modeled empirically based on observed irrigation rates or by calculating water supply and demand. Certain models can also calculate the irrigation demand as per the soil water deficit. In these implementations, irrigation is typically applied uniformly over the irrigated land regardless of crop types or irrigation techniques. Whereas, the latest version of Community Land Model (CLM) in the Community Terrestrial Systems Model (CTSM) uses a global distribution map of irrigation with 64 crop functional types (CFTs) to simulate the irrigation water demand. It can estimate irrigation water withdrawal from different sources and the amount or the areas irrigated with different irrigation techniques. Hence, we set up the model for the simulation period of 16 years from 2000 to 2015 to analyze the global irrigation demand at a spatial resolution of 1.9° × 2.5°. The simulated irrigation water demand is evaluated with the available observation data from FAO AQUASTAT database at the country scale. With the evaluated model, this study aims to suggest new sustainable scenarios for the ratios of irrigation water withdrawal, high depending on the withdrawal sources e.g. surface water and groundwater. With such scenarios, the CFT maps are considered as the determining factor for selecting the areas where the crop pattern can be altered for a sustainable irrigation water management depending on the available withdrawal sources. Overall, our study demonstrate that the scenarios for the future sustainable water resources management in terms of irrigation water withdrawal from the both the surface water and groundwater sources may overcome the excessive stress on exploiting the groundwater in major river basins globally.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3268-3276
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• 2023

The practice of identifying the potential zones for mineral exploration in a speedy and low-cost method includes the use of satellite imagery analysis as a part of remote sensing techniques. It is challenging to explore the iron mineralization of a region through conventional methods which are a time-consuming process. The current study utilizes the Hyperion satellite imagery for mapping the iron mineralization and associated geological features in the Irikkur region, Kannur, Kerala. Along with the remote sensing results, the field study and laboratory-based analysis were conducted to retrieve the ground truth point and geochemical proportion to verify the iron ore mineralization. The MC simulation showed for shielding properties indicate an increase in the linear attenuation coefficient with raising the Fe₂O₃+SiO₂ concentrations in the investigated rocks where it is varied at 0.662 MeV in the range 0.190 cm^-1 - 0.222 cm^-1 with rising the Fe₂O₃+SiO₂ content from 57.86 wt% to 71.15 wt%. The analysis also revealed that when the γ-ray energy increased from 0.221 MeV to 2.506 MeV, sample 1 had the largest linear attenuation coefficient, ranging from 9.33 cm1 to 0.12 cm^-1. Charnockite rocks were found to have exceptional shielding qualities, making them an excellent natural choice for radiation shielding applications.

• 대한토목학회논문집
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• 제30권3B호
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• pp.325-335
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• 2010

본 연구에서는 투수층 매설에 따른 해빈안정화의 효과를 논의하기 위하여, 파 투과성구조물 해빈/해저지반의 상호간섭을 직접해석 할 수 있는 3D-수치모델(LES-WASS-3D; 허동수와 이우동, 2007)을 이용하였다. 이 모델은 투과성구조물 내부의 유체저항으로서 층류저항, 난류저항, 관성저항을 포함하고 있으며 격자 크기보다 작은 와류를 고려하기 위하여 LES기법을 도입하고 있다. 먼저, 기존의 수리모형 실험치와 본 연구의 계산치를 비교 검토하여 이용한 수치모델의 타당성 및 유효성을 검증한 후, 해빈 내부에 투수층을 설치하여 수치시뮬레이션을 실시하였다. 수치실험결과를 통하여 투수층 매설에 따른 평균지하수위의 하강, 이안류 강도의 저하 등, 배수의 메커니즘을 파악한 후, 투수층의 배치형태(평균입경, 두께, 매설깊이, 경사) 및 입사파조건(파고, 주기)에 따른 해빈 내부의 평균지하수위분포에 대하여 고찰하였다.

• 한국환경농학회지
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• 제5권1호
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• pp.35-42
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• 1986

비소광산(砒素鑛山) 및 제련소(製鍊所) 인근답(隣近畓)에서 수확기(收穫期)에 토양(土壤)과 정조(正租)를 동시(同時)에 채취(採取)하여 토양중(土壤中) 비소(砒素)를 수용태(水容態)As, Al태(態)As, Fe태(態) As, Ca태(態)As, 잔여태(殘餘態)As로 분별분석(分別分析)하고 이들 형태별(形態別) As와 토양특성(土壤特性) 및 1N HCl가용성(可溶性) As함량(含量)과의 관계(關係)와 비소형태별(砒素形態別) 함량(含量) 및 1N HCl가용성함량(可溶性含量)과 현미중(玄米中) As함량(含量)과의 관계(關係)를 조사(調査)한 결과(結果)는 다음과 같다. 1. 형태별(形態別) As분포비(分布比)는 토양특성(土壤特性)에 따라 차이(次異)가 심(甚)하였으며, 무기태(無機態) As의 분포(分布)는 광산(鑛山) 및 제련소(製鍊所) 두지역 모두 Fe태(態)As>Al태(態)As>Ca태(態)As>수용성(水溶性)As의 순(順)이었고 잔여태(殘餘態)As(유기태(有機態)As+부용태(不溶態)As)는 광산지역(鑛山地域)이 제련소지역(製鍊所地域)보다 월등히 높았다. 2. pH가 높은 토양(土壤)일수록 두지역(地域) 모두 Al태(態)As 및 Fe태(態)As는 감소(減少)하나 Ca태(態)As 및 잔여태(殘餘態)As는 증가(增加)하는 경향(傾向)이며, 유기물(有機物) 함량(含量)과 이들 지역(地域)의 형태별(形態別) As분포(分布)와의 관계는 뚜렷한 경향(傾向)이 없었고 C.E.C가 높은 토양(土壤)일수록 Al태(態)As는 감소(減少)하나 그외(外) 형태(形態)의 As는 증가(增加)하는 경향(增加)임. 3. 토양중(土壤中) 활성(活性) 알루미늄 및 철함량(鐵含量)과 치환성(置換性) 칼슘함량(含量)은 토양중(土壤中) Al-As, Fe-As, 및 Ca-As분포비(分布比)와 각각정(各各正)의 상관(相關)을 나타내었으며 이들간의 상관(相關)은 광산지역(鑛山地域)이 제련소지역(製鍊所地域)보다 높았다. 4. 수용성(水溶性) 비소(砒素)를 제외(除外)한 토양중(土壤中) 비소형간(砒素形間)에는 서로 높은 정(正)의 상관(相關)이 있었고 비소형태(砒素形態)와 1N-HCl 침출법간(浸出法間)에도 같은 경향(傾向)이었다. 5. 현미중(玄米中) 비소함량(砒素含量)은 Al태(態)As함량(含量)과 가장 높은 상관(相關)을 나타내었으며 Fe태(態)As 및 Ca태(態)As와 Total As 및 1N HCl 가용성(可溶性) As함량(含量)과도 유의성(有意性) 있는 정(正)의 상관(相關)을 나타내었다.

• 대한기관식도과학회:학술대회논문집
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• 대한기관식도과학회 1977년도 제11차 학술대회연제 순서 및 초록
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• pp.6.2-7
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• 1977

사성은 후두의 정상 발성기능이 장애되있을때 생기며, 후두질환의 가장 중요하고 특유한 증상이다. 1885년 Morgagni가 최초로 후두암에 대해서 보고한 이래 최근 후두암에 대한 인식이 높아짐과 동시에 사회적으로 날로 심각한 문제가 되고 있는 공해 특히 대기오염으로 인한 기도증상으로 야기되는 후두질환증후인 사성을 호소하는 환자들이 증가되고 있는지 연구 고찰함이 의의가 있다고 생각되어, 저자들은 1970년 1월부터 1976년 12월까지 만 7년간 한일병원 이비인후과 외래에 사성을 주소로 내원한 400명의 환자에 대한 임상적 고찰을 하여 다음 몇가지 지견을 얻었기에 문헌적 고찰을 가하여 보고하는 바이다. 1. 이비인후과 신 외래환자 총 14,731명중 사성 환자가 400명으로 약 2.7%이였다. 2. 성별로는 남여비가 211 : 189로 약 1.1 : 1로써 남子가 약간 많았다. 3. 질환별로는 급성후두염 158례(39.5%). 만성후두염 103례(27.3%), 성대결절 37례(9.3%), 성대마비 34례(8.5%), 성대 polyp 32례(8%), 후두질 13례(3.25%), 후두결핵 9례(2.25%)의 순이었다. 4. 연령별로는 30세대가 113례(28.23%)로 가장 많았고 다음으로 40대, 20대, 순이였으며, 10대, 20대, 60대 이상은 비교적 저율이였다. 5. 성별질환분포는 후두암이 12 : 1, 후두polyp 27 : 5, 후두유두종 4 : 1로 남성에서 압도적으로 많았으며, 그 외질환은 남여 비슷한 율을 보였다. 6. 연령별질환분포는 50세대까지는 급만성후두염이 가장 많았고 30대에선 후두 polyp, 30대 및 40대에선 성대결절, 40대 및 50대에선 후두결핵과 성대미비, 50 대에서는 후두암이 최고율이였다. 7. 월별분포는 고루 산재되어 있었으며 그중 3월∼6월사이가 비교적 고율이었고 동절엔 비교적 낮았다. 8. 발병부터 초진까지의 기간은 10일이내가 103례(26%)로 가장 많았고 약 80%에서 발병 1년이내에 내원하였다.

• 한국해안·해양공학회논문집
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• 제29권6호
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• pp.286-304
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• 2017

본 연구에서는 어항 등과 같은 소규모 항에서 적용 가능한 격자블록결속에 의한 신형식의 원형유공케이슨을 제안하고, 이러한 방파제의 수리특성을 수치적으로 검토하였다. 본 연구에서 적용한 수치해석 코드는 최근들어 다양한 분야에서 공학적 문제해결을 위해 그 사용예가 급증하고 있는 공중사용허가서(오픈소스 기반) 라이선스 기반의 OpenFOAM(Open Field Operation and Manipulation)에 조파모듈, 투과층 해석모듈, 및 반사파 제어기능 등을 추가한 OLAFOAM을 적용하였다. 본 연구는 먼저, 1) 규칙파 하 3차원슬리트케이슨 방파제에서 파의 파압변동에 대해 기존의 실험 결과와 비교 검토하고, 2) 불규칙파를 조파하여 목표한 파의 재현과 주파수스펙트럼을 비교 검토하여 OLAFOAM의 타당성을 검증하였다. 이로부터 슬리트케이슨과 유사한 원형유공케이슨이 설치된 일정수심의 3차원수치파동수조에 불규칙파를 조파하여 유수실 폭과 유의파고 및 유의주기의 변화에 따른 원형유공케이슨 방파제에서 월파량, 반사율, 파압분포 및 그들의 상호연관성을 면밀히 검토 분석하였다. 이로부터 파압분포는 불투과연직벽체에 대한 Goda 식의 결과보다 매우 작은 결과를 나타내었으며, 반사율은 기존의 슬리트케이슨에서 반사율의 변동범위 내에 존재하는 것을 알 수 있었다.