Unmanned aerial vehicle(UAV) can acquire images with lower cost than conventional manned aircraft and commercial satellites. It has the advantage of acquiring high-resolution aerial images covering in the field area more than 50 ha. The purposes of this study is to develop the rice grain yield distribution using UAV. In order to develop a technology for estimating the rice yield using UAV images, time series UAV aerial images were taken at the paddy fields and the data were compared with the rice yield of the harvesting area for two rice varieties(Singdongjin, Dongjinchal). Correlations between the vegetation indices and rice yield were ranged from 0.8 to 0.95 in booting period. Accordingly, rice yield was estimated using UAV-derived vegetation indices(R2=0.70 in Sindongjin, R2=0.92 in Donjinchal). It means that the rice yield estimation using UAV imagery can provide less cost and higher accuracy than other methods using combine with yield monitoring system and satellite imagery. In the future, it will be necessary to study a variety of information convergence and integration systems such as image, weather, and soil for efficient use of these information, along with research on preparing management practice work standards such as pest control and nutrient use based on UAV image information.
Improvement of Cross-section Estimation Method for Flood Stage Analysis in Unmeasured Streams
전상민 Jun Sang Min , 황순호 Hwang Soon Ho , 송정헌 Song Jung-hun , 김시내 Kim Si Nae , 최순군 Choi Soon-kun , 강문성 Kang Moon Seong
The objective of this study was to improve the cross-sectional area and height estimation method using stream width. Stream water levels should be calculated together to simulate inundation of agricultural land. However, cross-sectional survey data of small rural rivers are insufficient. The previous study has developed regression equations between the width and the cross-sectional area and between the width and the height of stream cross-section, but can not be applied to a wide range of stream widths. In this study, cross-sectional survey data of 6 streams (Doowol, Chungmi, Jiseok, Gam, Wonpyeong, and Bokha stream) were collected and divided into upstream, midstream and downstream considering the locations of cross-sections. The regression equations were estimated using the complete data. R2 between the stream width and cross-sectional area was 0.96, and R2 between width and height was 0.81. The regression equations were also estimated using divided data for upstream, midstream and downstream considering the locations of cross-sections. The range of R2 between the stream width and cross-sectional area was 0.86 - 0.91, and the range of R2 between width and height was 0.79 ? 0.92. As a result of estimating the cross-sections of 6 rivers using the regression equations, the regression equations considering the locations of cross-sections showed better performance both in the cross-sectional area and height estimation than the regression equations estimated using the complete data. Hydrologic Engineering Center - River Analysis System (HEC-RAS) was used to simulate the flood stage analysis of the estimated and the measured cross-sections for 50-year, 100-year, and 200-year frequency floods. As a result of flood stage analysis, the regression equations considering the locations of cross-sections also showed better performance than the regression equations estimated using the complete data. Future research would be needed to consider the factors affecting the cross-sectional shape such as river slope and average flow velocity. This study can be useful for inundation simulation of agricultural land adjacent to an unmeasured stream.
Relationship Analysis of Reference Evapotranspiration and Heating Load for Water-Energy-Food Nexus in Greenhouse
김귀훈 Kim Kwihoon , 윤푸른 Yoon Pureun , 이윤희 Lee Yoonhee , 이상현 Lee Sang-hyun , 허승오 Hur Seung-oh , 최진용 Choi Jin-yong
Increasing crop production with the same amount of resources is essential for enhancing the economy in agriculture. The first prerequisite is to understand relationships between the resources. The concept of WEF (Water-Energy-Food) nexus analysis was first introduced in 2011, which helps to interpret inter-linkages among the resources and stakeholders. The objective of this study was to analyze energy-water nexus in greenhouse cultivation by estimating reference evapotranspiration and heating load. For the estimation, this study used the physical model to simulate the inside temperature of the agricultural greenhouse using heating, solar radiation, ventilated and transferred heat losses as input variables. For estimating reference evapotranspiration and heating load, Penman-Monteith equation and seasonal heating load equation with HDH (Heating Degree-Hour) was applied. For calibration and validation of simulated inside temperature, used were hourly data observed from 2011 to 2012 in multi-span greenhouse. Results of the simulation were evaluated using R2, MAE and RMSE, which showed 0.75, 2.22, 3.08 for calibration and 0.71, 2.39, 3.35 for validation respectively. When minimum setting temperature was 12℃ from 2013 to 2017, mean values of evapotranspiration and heating load were 687 mm/year and 2,147 GJ/year. For 18℃, Mean values of evapotranspiration and heating load were 707 mm/year and 5,616 GJ/year. From the estimation, the relationship between water and heat energy was estimated as 1.0~2.6 GJ/ton. Though additional calibrations with different types of greenhouses are necessary, the results of this study imply that they are applicable when evaluating resource relationship in the greenhouse cultivation complex.
Derivation of Channel and Floodplain Width Regression Reflecting Korean Channel Shapes in SWAT Model
이현구 Lee Hyeon-gu , 한정호 Han Jeongho , 이동준 Lee Dongjun , 임경재 Lim Kyoung-jae , 김종건 Kim Jonggun
In this study, the channel and floodplain widths are indirectly measured for three different watersheds using satellite images to reflect the shape of Korean channels in the Soil and Water Assessment Tool (SWAT) model. For measuring the channel and floodplain widths, multiple satellite images were referred to ensure the widest width of certain points. In the single channel, the widths at the multiple points were measured. Based on the measured data, the regression equations were derived to estimate the channel and floodplain widths according to watershed areas. Applying these developed equations, this study evaluated the effect of the change of channel and floodplain widths on the SWAT simulation by comparing to the measured streamflow data. The developed equations estimated larger channel width and smaller floodplain compared with those calculated in the current SWAT model. As shown in the results, there was no considerable changes in the predicted streamflow using the current and developed equations. However, the flow velocity and channel depth calculated from the developed equations were smaller than those of the current equations. The differences were caused by the effect of different channel geometries used for calculating the hydraulic characteristics. The channel geometries also affected the water quality simulation in channels because the hydraulic characteristics calculated by the channel geometries are directly related to the water quality simulation. Therefore, application of the river cross-sectional regression equation reflecting the domestic stream shape is necessary for accurate water quantity / quality and water ecosystem simulation using hydrological model.
The Monitoring and Evaluation of the Community Central Revitalization Project in Yeongwol - Focusing on the Community Empowerment Project in 2018 -
The present study aims to monitor three of the community empowerment projects implemented as part of the community central revitalization projects in Yeongwol. We used an established indicator (i.e., quantitative evaluation) as well as an interview (i.e., qualitative evaluation) throughout the monitoring process. The PM (project manager) committee members, consisting of six interdisciplinary experts, carried out the monitoring from 24th of October until the 26th of November 2018. We categorized the results of the monitoring into the aspects of needs, software, and hardware, and analyzed them as follows: First, although the locals were willing to take part in programs, they were in overall not well informed about the ongoing programs and the program that suits their needs the most. The service organization should therefore actively publicize the program and provide sufficient information about it .Second, instead of a one-off program, the locals should be empowered to take over the program eventually and develop it as a local business model. Last, the locals from the center as well as the outskirts of Yeongwol should organize a learning net, collaboratively develop a further program, and assess its effectiveness by employing a thorough monitoring system.
Experimental Study on the Effect of Air Chamber Size and Operation Parameters on the Performance of a Hydraulic Ram Pump
은골에농진에봉죠오지 Ngolle Enongene Ebong George , 홍성구 Hong Seong Gu
Motor pumps cannot be used in those areas where electricity is not accessible such as remote rural areas in many African countries. Hydraulic ram pump is one of the solutions for supplying water for irrigation or domestic uses. The hydraulic ram pumps are working based on the water hammer effect for pumping without external power or electricity. This study was conducted to investigate the effect of air chamber volume and operation parameters on the performance of the hydraulic ram pump which was assembled with common plumbing parts. The experimental results showed the volume of the air chamber did not affect the performance such as discharge rate and head. When drive heights were 1.7 and 2.35 m, the maximum discharge heads were up to 7 m and 10 m, respectively. When the air chamber volume was 1 L, discharge rates were 0.23 and 2.12 L/min under the drive heights of 1.7 and 2.35 m, respectively. The average energy efficiency of the hydraulic ram pump assembled in this study was about 60% for all the experimental conditions.
Field Model Test of the Non-power Soil Cleaning System
박찬근 Park Chan Keun , 이영학 Lee Young Hak , 홍석민 Hong Seok Min , 이달원 Lee Dal Won
Coastal and fishing facilities are gradually deteriorating in function due to the continual accumulation of soil sediments, which has affected local economic activities. Currently, there are many methods to remove soil sediments, but these methods are either a temporary solution or require a repetitive removal of the soil sediments, which is a huge financial burden for the maintenance of the facilities. To solve these problems, this study proposed a non-power soil cleaning system and evaluated field applicability by carrying out field model tests. The conditions for the evaluation focused on the drainage-elapsed time and drainage-outflow velocity according to the water level change in the water tank. In the field test, silty clay and sand were separately installed, and sedimentation soil removal test was practiced. As a result, the system was verified to have a sufficient outflow velocity for the removal of soil sediments. In addition, a generalization equation that can be used in different regions of the tide was suggested in this study. These results will greatly contribute to removing soil sediments in ports and dike gate facilities on the southwest coast. Since the system is an eco-friendly technology that does not require additional energy, thus it is expected to contribute to maintenance of sustainable facility performance as well as economic effect in the future.
Development of Evaluation Model of Pumping and Drainage Station Using Performance Degradation Factors
이종혁 Lee Jonghyuk , 이상익 Lee Sangik , 정영준 Jeong Youngjoon , 이제명 Lee Jemyung , 윤성수 Yoon Seongsoo , 박진선 Park Jinseon , 이병준 Lee Byeongjoon , 이준구 Lee Joongu , 최원 Choi Won
Development of Evaluation Model of Pumping and Drainage Station Using Performance Degradation Factors
이종혁 Lee Jonghyuk , 이상익 Lee Sangik , 정영준 Jeong Youngjoon , 이제명 Lee Jemyung , 윤성수 Yoon Seongsoo , 박진선 Park Jinseon , 이병준 Lee Byeongjoon , 이준구 Lee Joongu , 최원 Choi Won
Recently, natural disasters due to abnormal climates are frequently outbreaking, and there is rapid increase of damage to aged agricultural infrastructure. As agricultural infrastructure facilities are in contact with water throughout the year and the number of them is significant, it is important to build a maintenance management system. Especially, the current maintenance management system of pumping and drainage stations among the agricultural facilities has the limit of lack of objectivity and management personnel. The purpose of this study is to develop a performance evaluation model using the factors related to performance degradation of pumping and drainage facilities and to predict the performance of the facilities in response to climate change. In this study, we focused on the pumping and drainage stations belonging to each climatic zone separated by the Korea geographical climatic classification system. The performance evaluation model was developed using three different statistical models of POLS, RE, and LASSO. As the result of analysis of statistical models, LASSO was selected for the performance evaluation model as it solved the multicollinearity problem between variables, and showed the smallest MSE. To predict the performance degradation due to climate change, the climate change response variables were classified into three categories: climate exposure, sensitivity, and adaptive capacity. The performance degradation prediction was performed at each facility using the developed performance evaluation model and the climate change response variables.
General Inundation Modeling of Paddy Field Districts Considering Drainage Delay
전상민 Jun Sang Min , 이현지 Lee Hyun Ji , 황순호 Hwang Soon Ho , 송정헌 Song Jung-hun , 최순군 Choi Soon-kun , 강문성 Kang Moon Seong
The objective of this study was to develop a general inundation modeling technique considering the effect of drainage delay in the paddy field districts. In most studies, farmland inundation simulations have been conducted using previously developed watershed models. However, the water cycle in the paddy fields has a different structure from that of the general watershed, and the effect of the drainage delay should be considered. In this study, the drainage delay algorithm was developed using water balance equation, and the inundation modeling was performed for inundation-prone paddy fields located near Doowol stream. As a result, the depth of inundation was 43.1 cm and 45.2 cm, respectively, due to the 100-year and 200-year frequency rainfall. With the operation of drainage pump (0.1 ㎥/s), inundation depths decreased by 5.8 cm and 6.0 cm, respectively, and inundation time reduced by 20 hours and 21 hours, respectively for the 100-year and 200-year frequency rainfall. The result showed that the general inundation modeling technique developed in this study could reflect the effect of drainage delay due to the rise of external water level and the flooding reduction effect by operation of drainage pump. The results of this study are expected to be useful to establish measures for damage caused by farmland inundation.
A Study on the Location Assessment of Rural Village Construction Project
이병학 Lee Byunghark , 정남수 Jung Namsu , 김종봉 Kim Jongbong
If the new town development project begins with inappropriate location then it will be difficult to recruit tenants and the proportion of the infrastructure cost could increase. It is necessary to evaluate the feasibility of the new town development projects to solve this problem. This study aims to identify the current status of the new town development projects and draw up evaluation criteria by examining advanced researches.
To identify the importance of each village, we set up the weights through analytic hierarchy process. The evaluation criteria were classified into location conditions and economical efficiency. In the case of location conditions, it was classified into available size, geographical conditions, and accessibility. As a result of analyzing the questionnaire, it was subdivided into officially assessed land prices in case of economic efficiency. This study had some limitations, that is we focused on the location conditions and economic feasibility among other factors. Therefore further study should contain analysis more on socio-cultural aspects such as residents’ cooperation or will for this project. By adding results later, we can make more reasonable decisions when we choose appropriate area.
