• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.189-195
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• 1996

This study was carried out ont the longterm aged reinforced concrete housings for the prediction of life expectancy and the suggestion of fundamental informations on the durable concrete. In this paper, the durability of concrete is compared with carbonation depth, and the measutrments fo carbonation depth and properties have been made on the number of cores taken from structures. And finally, the relationships between carbonation rate and such properties as strength, absorption ratio, density were examined.

• 한국농공학회지
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• 제26권2호
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• pp.106-124
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• 1984

Monthly streanflow of watersheds is one of the most important elements for the planning, design, and management of water resources development projects, e.g., determination of storage requirement of reservoirs and control of release-water in lowflow rivers. Modeling of longterm runoff is theoretically based on water-balance analysis for a certain time interval. The effect of the casual factors of rainfall, evaporation, and soil-moisture storage on streamflow might be explained by multiple regression analysis. Using the basic concepts of water-balance and regression analysis, it was possible to develop a generalized model called the Regionalized Regression Model for Monthly Streamflow in Korean Watersheds. Based on model verification, it is felt that the model can be reliably applied to any proposed station in Korean watersheds to estimate monthly streamflow for the planning, design, and management of water resources development projects, especially those involving irrigation. Modeling processes and properties are summarized as follows; 1. From a simplified equation of water-balance on a watershed a regression model for monthly streamflow using the variables of rainfall, pan evaporation, and previous-month streamflow was formulated. 2. The hydrologic response of a watershed was represented lumpedly, qualitatively, and deductively using the regression coefficients of the water-balance regression model. 3. Regionalization was carried out to classify 33 watersheds on the basis of similarity through cluster analysis and resulted in 4 regional groups. 4. Prediction equations for the regional coefficients were derived from the stepwise regression analysis of watershed characteristics. It was also possible to explain geographic influences on streamflow through those prediction equations. 5. A model requiring the simple input of the data for rainfall, pan evaporation, and geographic factors was developed to estimate monthly streamflow at ungaged stations. The results of evaluating the performance of the model generally satisfactory.

• 수산해양기술연구
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• 제43권3호
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• pp.222-231
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• 2007

This paper represents a basic statistical examination on the navigability of ocean-going ship from the point of estimating the time lasting period when propeller racing occurred by using the basic probability theory and the statistics. The propeller racing is one of the most important seakeeping qualities in relation to the safety of the main engine and shafting system. The trend of the racing has been mainly investigated in order to estimate allowable maximum propeller diameter, operation of ocean-going ships, etc.. In those studies, the propeller racing generally and mainly means the situation (propeller exposed) in which the relative motion amplitude between ship hull and wave surface would exceed a depth of point in rotary disk propeller. Therefore, it seems that the magnitude of the amplitude and its exceeding frequency of propeller racing have been examined as a principal subject of study as usual. However, the time during which the amplitude exceeds the depth of point, that is, the propeller exposes in the air, must be also one of most important factor affecting the trend of propeller racing. Then, this paper proposes a new practical method for estimating the time lasting of exposed propeller related to propeller racing in rough-confused seas on the basis of the linear strip theory and the statistics. And, numerical examples of estimating the propeller racing probability are given for four wide ship forms. Finally the usefulness of the proposed method for predicting propeller racing based on the time lasting period is discussed.

• 디지털융복합연구
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• 제18권4호
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• pp.243-250
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• 2020

농작물 재배에 있어 가장 큰 위험 요소는 날씨이므로 재배지의 장기 농업 기상정보를 얻을 수 있다면 정식과 수확 시기 등을 예측할 수 있다. 따라서 체계적인 농작업을 기획하여 관리할 수 있으며 이는 농가의 안정적인 수확으로 이어질 것으로 기대한다. 본 연구는 GloSea5와 기계학습을 이용하여 효과적인 고랭지배추의 재배를 위한 장기 농업기상정보 예측 방법을 제시하였다. GloSea5는 계절예측시스템으로 최대 240일까지의 기상을 예측한다. 심층신경망과 공간랜덤포레스트를 이용하여 장기 일 평균기온을 예측한 결과 심층신경망이 공간랜덤포레스트에 비해 장기예측성능이 우수하였다. 하지만 공간랜덤포레스트는 강원도 전역의 기온을 짧은 시간에 예측하는 장점이 있다. 공간랜덤포레스트로 분석한 결과 여름철과 해발고도가 낮은 지역의 장기 일 평균기온이 잘 예측되었다.

• Journal of Astronomy and Space Sciences
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• 제41권1호
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• pp.1-15
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• 2024

The Korean heliospheric community, led by the Korea Astronomy and Space Science Institute (KASI), is currently assessing the viability of deploying a spacecraft at the Sun-Earth Lagrange Point L4 in collaboration with National Aeronautics and Space Administration (NASA). The aim of this mission is to utilize a combination of remote sensing and in situ instruments for comprehensive observations, complementing the capabilities of the L1 and L5 observatories. The paper outlines longterm scientific objectives, underscoring the significance of multi-point in-situ observations to better understand critical heliospheric phenomena. These include coronal mass ejections, magnetic flux ropes, heliospheric current sheets, kinetic waves and instabilities, suprathermal electrons and solar energetic particle events, as well as remote detection of solar radiation phenomena. Furthermore, the mission's significance in advancing space weather prediction and space radiation exposure assessment models through the integration of L4 observations is discussed. This article is concluded with an emphasis on the potential of L4 observations to propel advancements in heliospheric science.

• 한국대기환경학회지
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• 제32권1호
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• pp.114-126
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• 2016

Many cohort studies have reported associations of individual-level long-term exposures to $PM_{10}$ and health outcomes. Individual exposures were often estimated by using exposure prediction models relying on $PM_{10}$ data measured at national regulatory monitoring sites. This study explored spatial and temporal characteristics of regulatory $PM_{10}$ measurement data in South Korea and suggested $PM_{10}$ concentration metrics as long-term exposures for assessing health effects in cohort studies. We obtained hourly $PM_{10}$ data from the National Institute of Environmental Research for 2001~2012 in South Korea. We investigated spatial distribution of monitoring sites using the density and proximity in each of the 16 metropolitan cities and provinces. The temporal characteristics of $PM_{10}$ measurement data were examined by annual/seasonal/diurnal patterns across urban background monitoring sites after excluding Asian dust days. For spatial characteristics of $PM_{10}$ measurement data, we computed coefficient of variation (CV) and coefficient of divergence (COD). Based on temporal and spatial investigation, we suggested preferred long-term metrics for cohort studies. In 2010, 294 urban background monitoring sites were located in South Korea with a site over an area of $415.0km^2$ and distant from another site by 31.0 km on average. Annual average $PM_{10}$ concentrations decreased by 19.8% from 2001 to 2012, and seasonal $PM_{10}$ patterns were consistent over study years with higher concentrations in spring and winter. Spatial variability was relatively small with 6~19% of CV and 21~46% of COD across 16 metropolitan cities and provinces in 2010. To maximize spatial coverage and reflect temporal and spatial distributions, our suggestion for $PM_{10}$ metrics representing long-term exposures was the average for one or multiple years after 2009. This study provides the knowledge of all available $PM_{10}$ data measured at national regulatory monitoring sites in South Korea and the insight of the plausible longterm exposure metric for cohort studies.

• 한국지리정보학회지
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• 제10권4호
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• pp.111-121
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• 2007

도시산업구조의 진단과 예측은 지속가능한 도시발전계획수립을 위한 주요한 과제이다. 지금까지의 산업관련 도시공간구조 연구들은 주로 도시산업체 자료나 총 종사자수 자료를 활용하여 산업유형별 공간분포의 측정에 집중되어져 왔다. 그러나 최근 비정규직 문제를 포함한 근로자의 종사상 지위가 중요한 이슈가 되는 시점에서 본 연구는 읍면동 단위의 1994년 및 2004년 종사상 지위별 자료를 수집하고 동 변화자료를 기반으로 공간분석 단위를 일치시킨 후 GIS를 활용하여 종사상 지위분류체계 자료를 활용한 도시산업구조의 질적 변화를 공간적 관점에서 해석하였다. GIS환경에서 부산시 산업구조의 종사상지위 유형별 분석 결과는 다음과 같다. 첫째, 전통적인 노동집약적 산업이 한계에 부딪히고, 서비스업 및 도소매업은 영세한 생계형으로 진행되어 부산의 고용흡수력이 떨어질 수밖에 없었으며 통계상으로는 종사자의 수가 증가하였으나 비정규직과 비임금 노동자가 급증하면서 부산지역 일자리의 질이 하락하고 있는 것으로 측정되었다. 둘째, 전통적인 도심지는 쇠퇴하는 반면 신도시나 신흥공업단지가 형성된 지역, 제조업보다 서비스업이 발달한 지역이 일자리가 증가하는 경향을 보였다. 본 연구의 결과는 도시발전의 근간이 되는 산업구조의 행태적 패턴 뿐 아니라 종사상지위라는 질적 평가를 통한 장기적 차원의 산업발전계획안 마련을 위한 기초자료로서의 활용을 기대한다.