• 한국농공학회논문집
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• 제57권4호
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• pp.61-71
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• 2015

Quantitative variability of AMSR2 (Advanced Microwave Scanning Radiometer 2) soil moisture data shows that the remotely sensed soil moisture is underestimated during Spring and Winter seasons and is overestimated during Summer and Fall seasons. Therefore the bias correction of the remotely sensed data is essential for the purpose of water resource management. To enhance their applicability, the bias of AMSR2 soil moisture data was corrected using ground observation data at Cheorwon Chuncheon, Suwon, Cheongju, Jeonju, and Jinju sites. Test statistics demonstrated that the correlation coefficient R is improved from 0.107~0.328 to 0.286~0.559 and RMSE is improved from 9.46~14.36 % to 5.38~9.62 %. Bias correction using ground network data improved the applicability of remotely sensed soil moisture data.

• 한국농공학회논문집
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• 제46권7호
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• pp.15-21
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• 2004

This study is to present a standardized agricultural land use classification scheme at various spatial resolution (from 1 m to 30 m) of satellite images including Landsat TM, KOMPSAT-1 EOC, ASTER VNIR and IKONOS panchromatic (PAN) and multi-spectral (MS) images. The satellite images were interpreted especially for identifying agricultural land use, crop types, agricultural facilities and structures of 18 items. It was found that there is a threshold spatial resolution between 4 m and 6.6 m to identify the full items. Thus it is suggested that IKONOS fusion image (MS enhanced by PAN) is required to produce land use map for agricultural purpose.

• 한국수자원학회논문집
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• 제33권S1호
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• pp.388-393
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• 2000

• Advances in concrete construction
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• 제16권3호
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• pp.141-153
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• 2023

In order to develop and take full advantage of pasture fiber and waste concrete, this article studied how different amounts of pasture fiber influenced the toughness and pore structure of concrete with different replacement rates of recycled fine aggregate. Pasture fiber recycled concrete constitutive equations were established under idealized stiffness and toughness damage rate, based on fracture energy and damage mechanics theories. The relationship between pore structure and toughness was studied utilizing nuclear magnetic resonance and fractal theory. The toughness of text groups (0% (JZ), 10% (ZS10), 20% (ZS20)) first increased and then decreased with increasing amounts of pasture fiber, based on the damage rate of toughness. The toughness of concrete samples with recycled fine aggregate and pasture fiber is negatively correlated to the fractal dimension of small and medium-sized pores with a pore size of 0-500 nm. At a replacement rate of 10% of the recycled fine aggregate, the fractal dimension of the air voids (r: 500-9000 nm, i.e., Lg(r) ∈ [2.7, 3.9]) shows a gradual decrease with the increase of grass fiber dosage, indicating that with such a replacement rate of the recycled fine aggregate, the increase of pasture fiber can reduce the complexity of the pore structure of the air voids (500-9000 nm).

• 한국농공학회논문집
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• 제58권4호
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• pp.37-46
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• 2016

This study is to estimate COMS (Communication, Ocean and Meteorological Satellite) daily land surface temperature (LST) of Korea Peninsula from 15 minutes interval COMS LST (COMS LST-15) satellite data. Using daily observed LST data of Automated Agriculture Observing System (AAOS) 11 stations from January 2013 to May 2015, the COMS daily LST was compared and validated. For the representative time for daily mean LST value from COMS LST-15, the time of 23 : 45 and 0:00 showed minimum deviations with AAOS daily LST. The time zone from 23 : 45 to 1:15 and from 7 : 30 to 9 : 45 showed high determination coefficient (R2) of 0.88 and 0.90 respectively. The daily COMS LST by averaging COMS LST-15 of the day showed R2 of 0.83. From the 5 cases of results, the COMS daily LST could be extracted from the average LST by using 15 minutes data from 7 : 30 to 9 : 45.

• 한국농공학회논문집
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• 제57권2호
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• pp.15-26
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• 2015

The purpose of this paper is to develop a software tool, PGA-CC (Projection of hydrology via Grid-based Assessment for Climate Change) to evaluate the present hydrologic cycle and the future watershed hydrology by climate change. PGA-CC is composed of grid-based input data pre-processing module, hydrologic cycle calculation module, output analysis module, and output data post-processing module. The grid-based hydrological model was coded by Fortran and compiled using Compaq Fortran 6.6c, and the Graphic User Interface was developed by using Visual C#. Other most elements viz. Table and Graph, and GIS functions were implemented by MapWindow. The applicability of PGA-CC was tested by assessing the future hydrology of South Korea by HadCM3 SRES B1 and A2 climate change scenarios. For the whole country, the tool successfully assessed the future hydrological components including input data and evapotranspiration, soil moisture, surface runoff, lateral flow, base flow etc. From the spatial outputs, we could understand the hydrological changes both seasonally and regionally.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.580-583
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• 2007

Various matching methods have been introduced by investigators to improve digital elevation model (DEM) accuracy of satellite imagery. This study proposed an area-based matching method according to land cover property using correlation coefficient of pixel brightness value between the two images for DEM generation from IKONOS stereo imagery. For this, matching line (where "matching line" implies straight line that is approximated to complex nonlinear epipolar geometry) is established by exterior orientation parameters to minimize search area. The matching is carried out based on this line. Land cover classes are divided off into water, urban land, forest and agricultural land. Matching size is selected using a correlation-coefficient image in the four areas. The selected sizes are $81{\times}81$ pixels window, $21{\times}21$ pixels window, $119{\times}119$ pixels window and $51{\times}51$ pixels window in the water area, urban land, forest land and agricultural land, respectively. And hence, DEM is generated from IKONOS stereo imagery using the selected matching sizes and land cover map on the four types.

• 한국농공학회논문집
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• 제58권5호
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• pp.1-10
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• 2016

Drought is a slow-varying natural hazard that is characterized by various factors such that reliable drought forecasting along with uncertainties estimation has been a major issue. In this study, we proposed a stochastic simulation technique based scheme for providing a set of drought scenarios. More specifically, this study utilized a nonstationary Hidden markov model that allows us to include predictors such as climate state variables and global climate model's outputs. The simulated rainfall scenarios were then used to generate the well-known meteorological drought indices such as SPI, PDSI and PN for the three dam watersheds in South Korea. It was found that the proposed modeling scheme showed a capability of effectively reproducing key statistics of the observed rainfall. In addition, the simulated drought indices were generally well correlated with that of the observed.

• 한국농공학회논문집
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• 제52권1호
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• pp.61-68
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• 2010

토지피복은 대부분의 수문 수질 모형의 중요한 매개변수로서, 수자원 변화 예측에 중요한 입력자료로 활용되고 있다. 본 연구에서는 개선된 CA (Cellular Automata)-Markov 기법을 이용하여 충주댐유역의 미래 산림식생변화에 대한 예측을 시도하였다. 예측과정으로 과거의 Landsat TM 영상 (1985, 1990, 1995, 2000)을 이용하여 기법의 정확도 검증 및 산림분포의 변화경향을 파악하고, Landsat 산림은 2000년과 2005년의 NOAA AVHRR NDVI값을 기준으로 침엽수림, 혼효림, 활엽수림의 3종으로 구분한 후, 이를 이용하여 2030년, 2060년, 2090년의 식생변화를 추정하는 방법을 제안하였다. 이 방법의 적용결과, 2000년과 비교하여 2090년의 활엽수림과 혼효림은 각각 14.3 %, 11.6 % 증가하였으며, 침엽수림은 24.9 % 감소하는 것으로 나타났다. 과거의 경향성에 의해 예측을 시도한 본 연구결과는 미래 토지피복 변화에 따른 수문 수질 영향 분석시 지표 조건의 불확실성을 줄이는데 활용될 수 있다고 판단된다.

• 한국지리정보학회지
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• 제23권4호
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• pp.120-139
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• 2020

본 연구에서는 CLUE-s(Conversion of Land Use and its Effects at Small regional extent)와 RCP(Representative Concentration Pathway) 4.5 및 8.5 HadGEM3-RA(Hadley Centre Global Environmental Model version 3 Regional Atmosphere)시나리오를 사용하여 미래 농지이용 변화와 기후변화가 관개 필요수량에 미치는 영향을 평가하였다. 논산시(55,517.9ha)의 농지이용 항목으로 논, 밭, 시설재배지를 고려하고 DIROM (Daily Irrigation Reservoir Operation Model)을 이용해 탑정저수지 수혜구역(5,713.3ha)에 대한 관개 필요수량(Irrigation Water Requirement, IWR)을 추정하였다. CLUE-s를 이용한 미래 농지이용 변화를 모의하기 위해 환경부의 2007년, 2013년, 2019년의 토지피복도 6개 항목(수역, 시가지, 논, 밭, 산림, 시설재배지)을 적용하였다. 그 결과, 2100년은 2013년에 비해 논과 밭이 5.0%, 7.6% 감소했으며, 시설재배지는 24.7% 증가하는 것으로 전망되었다. 미래의 농지이용과 기후변화를 모두 고려한 경우의 RCP 4.5 및 RCP 8.5 모두 2090s(2090~2099) IWR은 미래 기후변화만 고려한 경우에 비해 논과 밭에서는 각각 2.1%, 1.0% 감소하고 시설재배지에서는 11.4% 증가하는 것으로 전망되었다.