ALE 수치기법에 의한 연료탱크 선회운동 동응답 해석

홍상일(S. I. Hong),김민정(M. J. Kim),조진래(J. R. Cho),박태학(T. H. Park),이우용(W. Y. Lee) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.4

The dynamic response of a baffled fuel-storage tank in turnaround motion is simulated using the ALE finite element method. Fuel-storage tank is a representative example of fluid-structure interaction problems, in which structure deformation and fluid motion interact strongly. For the accurate dynamic-response analysis of this complicated fluid-structure system, we employed ALE(arbitrary Lagrangian-Eulerian) numerical approach. Five types of fuel-storage tank models with respect to the baffle number are considered to examine the effect of baffles on the dynamic-response, such as effective stress, displacement and the free surface motion of internal fluid.

구스아스팔트로 시공된 사장교 강상판 바닥판에 대한 열영향 특성

김민우,김두환,박태순,홍상일,임현묵,김종현 한국방재학회 2015 한국방재학회 학술발표대회논문집 Vol.14 No.-

강바닥판은 콘크리트 바닥판에 비해 강성이 작아 차량의 윤하중에 의해 국부적으로 큰 변형이 발생하여 포장표면에 인장응력을 유발시켜 포장균열 발생의 원인이 된다. 또한, 용접이음부의 포장이 균일한 두께로 포설되지 않거나 강바닥판과 아스팔트 포장 사이의 부착성 부족으로 인해 공용 중 포장손상이 발생한다. 최근 이러한 문제점을 해결하기 위해 강바닥판 교량에 구스 아스팔트와 같은 부착성 및 내구성이 우수한 특수 아스팔트 포장을 실시하는 경우가 늘고 있으나 구스 아스팔트는 일반 아스팔트 보다 약 100℃정도 높은 고온상태에서 포설되기 때문에 강바닥판의 온도가 100℃~130℃ 정도 상승하게 된다. 이와 같은 온도상승은 포장 시공 중 강바닥판의 변형을 유발하고 포장 완료 후에도 강바닥판 교량의 품질에 악영향을 미친다. 이에 본 연구에서는 구스 아스팔트 포장온도가 강바닥판의 열변형에 미치는 영향을 검토하여 강상판 교량의 시공상에 문제점이 되고 있는 포장문제를 해결하고자 하였다. 해석결과, 지점과 교각의 2개의 교량받침과 Shear key가 설치되어 구스아스팔트 포장 시공 도중 문제시 되고 있는 지점의 부반력에 의한 받침의 들림이나 신축이음의 영향, 교축방향 변위의 영향은 모두 허용치 범위 내에 있는 것으로 나타났다. 또한, 보부재에 모델링된 U-리브, 종형 및 횡형의 단부부재에 발생하는 응력은 강바닥판 또는 평판에 발생하는 응력에 비하여 작은 것으로 나타났다.

Estimation of Chinese Cabbage Growth by RapidEye Imagery and Field Investigation Data

나상일,이경도,백신철,홍석영 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.5

Chinese cabbage is one of the most important vegetables in Korea and a target crop for market stabilization as well. Remote sensing has long been used as a tool to extract plant growth, cultivated area and yield information for many crops, but little research has been conducted on Chinese cabbage. This study refers to the derivation of simple Chinese cabbage growth prediction equation by using RapidEye derived vegetation index. Daesan-myeon area in Gochang-gun, Jeollabuk-do, Korea is one of main producing district of Chinese cabbage. RapidEye multi–spectral imagery was taken on the Daesan-myeon five times from early September to late October during the Chinese cabbage growing season. Meanwhile, field reflectance spectra and five plant growth parameters, including plant height (P.H.), plant diameter (P.D.), leaf height (L.H.), leaf length (L.L.) and leaf number (L.N.), were measured for about 20 plants (ten plants per plot) for each ground survey. The normalized difference vegetation index (NDVI) for each of the 20 plants was measured using an active plant growth sensor (Crop CircleTM) at the same time. The results of correlation analysis between the vegetation indices and Chinese cabbage growth data showed that NDVI was the most suited for monitoring the L.H. (r=0.958~0.978), L.L. (r=0.950~0.971), P.H. (r=0.887~0.982), P.D. (r=0.855~0.932) and L.N. (r=0.718~ 0.968). Retrieval equations were developed for estimating Chinese cabbage growth parameters using NDVI. These results obtained using the NDVI is effective provided a basis for establishing retrieval algorithm for the biophysical properties of Chinese cabbage. These results will also be useful in determining the RapidEye multi-spectral imagery necessary to estimate parameters of Chinese cabbage.

Estimation of Corn and Soybean Yields Based on MODIS Data and CASA Model in Iowa and Illinois, USA

나상일,홍석영,김예현,이경도 한국토양비료학회 2014 한국토양비료학회지 Vol.47 No.2

The crop growing conditions make accurate predictions of yield ahead of harvest time difficult. Suchpredictions are needed by the government to estimate, ahead of time, the amount of crop required to beimported to meet the expected domestic shortfall. Corn and soybean especially are widely cultivatedthroughout the world and a staple food in many regions of the world. On the other hand, the CASA(Carnegie-Ames-Stanford Approach) model is a process-based model to estimate the land plant NPP (NetPrimary Productivity) based on the plant growing mechanism. In this paper, therefore, a methodology for theestimation of corn/soybean yield ahead of harvest time is developed specifically for the growing conditionsparticular to Iowa and Illinois. The method is based on CASA model using MODIS data, and uses Net PrimaryProductivity (NPP) to predict corn/soybean yield. As a result, NPP at DOY 217 (in Illinois) and DOY 241 (inIowa) tend to have high correlation with corn/soybean yields. The corn/soybean yields of Iowa in 2013 wasestimated to be 11.24/3.55 ton/ha and Illinois was estimated to be 10.09/3.06 ton/ha. Errors were 6.06/17.58%and -10.64/-7.07%, respectively, compared with the yield forecast of the USDA. Crop yield distributions in2013 were presented to show spatial variability in the state. This leads to the conclusion that NPP changes inthe crop field were well reflected crop yield in this study.

Temporal and Spatial Variation of Soil Moisture in Upland Soil using AMSR2 SMC

나상일,이경도,김숙경,홍석영 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.6

Temporal and spatial variation of soil moisture is important for understanding patterns of climate change, for developing and evaluating land surface models, for designing surface soil moisture observation networks, and for determining the appropriate resolution for satellite-based remote sensing instruments for soil moisture. In this study, we measured several soil moistures in upland soil using Advanced Microwave Scanning Radiometer 2 (AMSR2) Soil Moisture Content (SMC) during eight-month period in Chungbuk province. The upland soil moisture properties were expressed by simple statistical methods (average, standard deviation and coefficient of variation) from the monthly context. Supplementary studies were also performed about the effect of top soil texture on the soil moisture responses. If the results from this study were utilized well in specific cities and counties in Korea, it would be helpful to establish the countermeasures and action plans for preventing disasters because it was possible to compare with the relationship between soil moisture and top soil texture of each region. And it would be the fundamental data for estimating the effect of future agricultural plan.

봄배추 생육이상 평가를 위한 드론 열적외 영상 기반 작물 수분 스트레스 지수(CWSI) 분포도 작성

나상일,안호용,박찬원,홍석영,소규호,이경도 대한원격탐사학회 2020 大韓遠隔探査學會誌 Vol.36 No.5

Crop water stress can be detected based on soil moisture content, crop physiological characteristics and remote-sensing technology. The detection of crop water stress is an important issue for the accurate assessment of yield decline. The crop water stress index (CWSI) has been introduced based on the difference between leaf and air temperature. In this paper, drone-based thermal infrared image was used to map of crop water stress in water control plot (WCP) and water deficit plot (WDP) over spring chinese cabbage fields. The spatial distribution map of CWSI was in strong agreement with the abnormal growth response factors (plant height, plant diameter, and measured value by chlorophyll meter). From these results, CWSI can be used as a good method for evaluation of crop abnormal growth monitoring. 작물 수분 스트레스는 토양수분 함량, 농작물 생리학적 특성 및 원격탐사 기술을 이용하여 감지할 수 있으며, 작물의 생산량 감소를 평가하는데 매우 중요하다. 작물 수분 스트레스 지수(CWSI)는 작물의 엽온과 기온의 차이를 이용하여 산출할 수 있다. 본 연구에서는 드론 기반 열적외 영상을 이용하여 봄배추를 대상으로 관수 처리구(WCP)와 무관수 처리구(WDP)에 대한 CWSI 분포도를 작성하였다. 그 결과, CWSI 공간분포는 배추의 생육이상 반응 요소(구고, 구직경 및 엽록소 함량 측정치)와 높은 일치율을 나타내었다. 따라서 CWSI는 작물 생육이상 모니터링 및 평가에 좋은 수단으로 활용 가능할 것으로 판단된다.

Status of Rice Paddy Field and Weather Anomaly in the Spring of 2015 in DPRK

홍석영,박혜진,장근창,나상일,백신철,이경도,안중배 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.5

To understand the impact of 2015 spring drought on crop production of DPRK (Democratic People’s Republic of Korea), we analyzed satellite and weather data to produce 2015 spring outlook of rice paddy field and rice growth in relation to weather anomaly. We defined anomaly of 2015 for weather and NDVI in comparison to past 5 year-average data. Weather anomaly layers for rainfall and mean temperature were calculated based on 27 weather station data. Rainfall in late April, early May, and late May in 2015 was much lower than those in average years. NDVI values as an indicator of rice growth in early June of 2015 was much lower than in 2014 and the average years. RapidEye and Radarsat-2 images were used to monitor status of rice paddy irrigation and transplanting. Due to rainfall shortage from late April to May, rice paddy irrigation was not favorable and rice planting was not progressed in large portion of paddy fields until early June near Pyongyang. Satellite images taken in late June showed rice paddy fields which were not irrigated until early June were flooded, assuming that rice was transplanted after rainfall in June. Weather and NDVI anomaly data in regular basis and timely acquired satellite data can be useful for grasping the crop and land status of DPRK, which is in high demand.

시계열 마스크 맵이 논벼 NDVI와 단수와의 관계에 미치는 영향

나상일,안호용,박찬원,홍석영,소규호,이경도 대한원격탐사학회 2020 大韓遠隔探査學會誌 Vol.36 No.5

본 연구의 목적은 (1) MCD12Q1 자료를 이용하여 시계열 마스크 맵 작성하여 (2) 시계열 마스크 맵의 연차별 논벼 재배면적 변화를 추출하고, (3) MYD13Q1 NDVI와 단수와의 상관계수를 비교하여 (4) 적용성을 검토하는 것이다. 이를 위해 2002년부터 2019년까지의 연도별MCD12Q1 PFT 자료를 수집하여 시계열 마스크 맵을 작성하고 고정형 마스크 맵과 비교하였다. 그 결과, 시계열 마스크 맵에 의한 논벼 재배면적이 실제 논벼 재배면적의 변동 특성을 잘 반영하고 있는 것으로 나타났으며, 고정형 마스크 맵과 비교하여 NDVI와 논벼 단수와의 상관계수도 높게 나타나 시계열 마스크 맵이 논벼 고유의 식생지수 추출 및 작황 모니터링, 단수 추정의정확도를 높이는 방법임을 확인하였다. The objectives of this study were (1) to develop a temporal mask map using MCD12Q1 data, and (2) to extract the annual variations in paddy, (3) to investigate the correlation analysis between MYD13Q1 NDVI and rice yield, and (4) to review its applicability. For these purposes, the temporal mask map was created using annual MCD12Q1 PFT data from 2002 to 2019, and compared with the fixed mask map. As a result, it found that the temporal mask map well reflected the variations of the paddy area. In addition, the correlation coefficient between NDVI and rice yield was also high significant as compared to the fixed mask map. Therefore, the temporal mask map will be useful for NDVI extraction, crop monitoring, and estimation of rice yield.

Spatial Downscaling of AMSR2 Soil Moisture Content using Soil Texture and Field Measurements

나상일,이경도,백신철,홍석영 한국토양비료학회 2015 한국토양비료학회지 Vol.48 No.6

Soil moisture content is generally accepted as an important factor to understand the process of crop growth and is the basis of earth system models for analysis and prediction of the crop condition. To continuously monitor soil moisture changes at kilometer scale, it is demanded to create high resolution data from the current, several tens of kilometers. In this paper we described a downscaling method for Advanced Microwave Scanning Radiometer 2 (AMSR2) Soil Moisture Content (SMC) from 10 km to 30 m resolution using a soil texture and field measurements that have a high correlation with the SMC. As a result, the soil moisture variations of both data (before and after downscaling) were identical, and the Root Mean Square Error (RMSE) of SMC exhibited the low values. Also, time series analyses showed that three kinds of SMC data (field measurement, original AMSR2, and downscaled AMSR2) had very similar temporal variations. Our method can be applied to downscaling of other soil variables and can contribute to monitoring small-scale changes of soil moisture by providing high resolution data.

벼 수량 자료의 추세분석을 통한 MODIS NDVI 및 기상자료 기반의 벼 수량 추정 모형 개선

나상일 ( Sang-il Na ),홍석영 ( Suk-young Hong ),안호용 ( Ho-yong Ahn ),박찬원 ( Chan-won Park ),소규호 ( Kyu-ho So ),이경도 ( Kyung-do Lee ) 대한원격탐사학회 2021 大韓遠隔探査學會誌 Vol.37 No.2

장기적인 시계열 수량 평균이 기술적인 발전 요인에 의해 증가하는 추세를 제거하여, 기존 MODIS NDVI 및 기상자료를 이용한 우리나라 벼 수량 추정 모형을 개선하고자 하였다. 이를 위해 2002년부터 2019년까지의 NDVI (MYD13Q1)와 기상자료를 사용하여 다중 선형 회귀 분석을 수행하였다. 벼 수량 추세를 분석하고 이를 제거하여 모형을 보완하였다. 개선된 모형을 이용하여 추정한 벼 수량과 수량 통계 값 간의 상관 분석을 통해 추세 제거에 따른 정확도를 평가하였다. 그 결과, 추세가 제거된 벼 수량 추정 모형에 의해 예측된 수량이 통계 수량의 연간 변동 특성을 잘 반영하고 있는 것으로 나타났다. 추세 제거 전의 모형과 비교하여 통계 수량과의 상관계수와 결정계수도 높게 나타났다. 따라서 추세 제거 방법이 벼 수량 추정 모형을 효과적으로 보정하는 방법임을 확인하였다. By removing the increasing trend that long-term time series average of rice yield due to technological advancement of rice variety and cultivation management, we tried to improve the rice yield estimation model which developed earlier using MODIS NDVI and meteorological data. A multiple linear regression analysis was carried out by using the NDVI derived from MYD13Q1 and weather data from 2002 to 2019. The model was improved by analyzing the increasing trend of rime-series rice yield and removing it. After detrending, the accuracy of the model was evaluated through the correlation analysis between the estimated rice yield and the yield statistics using the improved model. It was found that the rice yield predicted by the improved model from which the trend was removed showed good agreement with the annual change of yield statistics. Compared with the model before the trend removal, the correlation coefficient and the coefficient of determination were also higher. It was indicated that the trend removal method effectively corrects the rice yield estimation model.