• Journal of The Korean Society of Agricultural Engineers
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• v.66 no.5
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• pp.15-27
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• 2024

Agriculture is recognized as an important anthropogenic cause of non-point source loads. Improved understanding of non-point source loads according to fertilization practices can promote climate change and eutrophication mitigation. Thus, this study evaluated the impact of conventional and standard fertilization practices on non-point pollution (NPP) loads in a dual-cropping system, utilizing the Agricultural Policy/Environmental eXtender (APEX) model. Our research objectives were twofold: firstly, to calibrate and validate the APEX model with observed data through experiments from 2018 to 2023; and secondly, to compare the NPP loads under conventional and standard fertilization practices. The model calibration and validation showed satisfactory performance in simulating nitrogen (N) and phosphorus (P) loads, illustrating the model's applicability in a Korean agricultural setting. The simulation results under conventional fertilization practices revealed significantly higher NPP loads compared to the standard fertilization, with P loads under conventional practices being notably higher. Our findings emphasize the crucial role of recommended fertilization practices in reducing non-point source pollution. By providing a quantitative assessment of NPP loads under different fertilization practices, this study contributes valuable information to sustainable nutrient management in agricultural systems facing the dual challenges of climate change and environmental conservation.

• Journal of Climate Change Research
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• v.8 no.4
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• pp.287-295
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• 2017

This paper provides a mathematical approach for estimating flood risks due to the effects of climate change by developing a one dimensional (1D) hydraulic model for the mountainous river reaches located close to the Yeongwol thermal power plant. Input data for the model, including topographical data and river discharges measured every 10 minutes from July $1^{st}$ to September $30^{th}$, 2013, were imported to a 1D hydraulic model. Climate change scenarios were estimated by referencing the climate change adaptation strategies of the government and historical information about the extreme flood event in 2006. The down stream boundary was determined as the friction slope, which is 0.001. The roughness coefficient of the main channels was determined to be 0.036. The results show the effectiveness of the riverbed widening strategy through the six flooding scenarios to reduce flood depth and flow velocity that impact on the power plant. In addition, the impact of upper Namhan River flow is more significant than Dong River.

• Journal of Climate Change Research
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• v.9 no.3
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• pp.283-291
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• 2018

The purpose of this study is to analyze the effects of useof weather and climate information on farmer income. To accomplish the objective of the study a farm survey was conducted, whose target respondents were local correspondents and reporters of the Korea Rural Economic Institute. The ordered logit model was employed for empirical analysis on determining whether use of weather and climate information affects farmer income. The analysis results show that the greater is farmer use of short-range weather forecasts, the higher is the income. The results also show higher farmers income with use of short-range special weather forecasts. Based upon the empirical results, the dissemination of more precise weather and climate information is suggested to increase farmer income.

• Journal of The Korean Society of Grassland and Forage Science
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• v.41 no.1
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• pp.47-55
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• 2021

The objective of this study was to access the effect of climate and soil factors on alfalfa dry matter yield (DMY) by the contribution through constructing the yield prediction model in a general linear model considering climate and soil physical variables. The processes of constructing the yield prediction model for alfalfa was performed in sequence of data collection of alfalfa yield, meteorological and soil, preparation, statistical analysis, and model construction. The alfalfa yield prediction model used a multiple regression analysis to select the climate variables which are quantitative data and a general linear model considering the selected climate variables and soil physical variables which are qualitative data. As a result, the growth degree days(GDD) and growing days(GD), and the clay content(CC) were selected as the climate and soil physical variables that affect alfalfa DMY, respectively. The contributions of climate and soil factors affecting alfalfa DMY were 32% (GDD, 21%, GD 11%) and 63%, respectively. Therefore, this study indicates that the soil factor more contributes to alfalfa DMY than climate factor. However, for examming the correct contribution, the factors such as other climate and soil factors, and the cultivation technology factors which were not treated in this study should be considered as a factor in the model for future study.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.1 no.1
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• pp.58-67
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• 2020

Terrestrial ecosystems influence climate change via their climate regulation function, which is manifested within the carbon, water, and energy circulation between the atmosphere and surface. However, it has been challenging to quantify the climate regulation of terrestrial ecosystems and identify its regional distribution, which provides useful information for establishing regional climate-mitigation plans as well as facilitates better understanding of the interactions between the climate and land processes. In this study, a land surface model (LSM) that represents the land-atmosphere interactions and plant phenological variations was introduced to assess the contributions of terrestrial ecosystems to atmospheric warming or cooling effects over East Asia over the last half century. Three main climate-regulating components were simulated: net radiation flux, carbon exchange, and moisture flux at the surface. Then, the contribution of each component to the atmospheric warming or cooling (negative or positive feedback to the atmosphere, respectively) was investigated. The results showed that the terrestrial ecosystem over the Siberian region has shown a relatively large increase in positive feedback due to the enhancement of biogeochemical processes, indicating an offset effect to delay global warming. Meanwhile, the Gobi Desert shows different regional variations: increase in positive feedback in its southern part but increase in negative one in its eastern part, which implies the eastward movements of desert areas. As such, even though the LSM has limitations, this model approach to quantify the climate regulation is useful to extract the relevant characteristics in its spatio-temporal variations.

• The Plant Pathology Journal
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• v.36 no.5
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• pp.406-417
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• 2020

Early warning services for crop diseases are valuable when they provide timely forecasts that farmers can utilize to inform their disease management decisions. In South Korea, collaborative disease controls that utilize unmanned aerial vehicles are commonly performed for most rice paddies. However, such controls could benefit from seasonal disease early warnings with a lead time of a few months. As a first step to establish a seasonal disease early warning service using seasonal climate forecasts, we developed the EPIRICE Daily Risk Model for rice blast by extracting and modifying the core infection algorithms of the EPIRICE model. The daily risk scores generated by the EPIRICE Daily Risk Model were successfully converted into a realistic and measurable disease value through statistical analyses with 13 rice blast incidence datasets, and subsequently validated using the data from another rice blast experiment conducted in Icheon, South Korea, from 1974 to 2000. The sensitivity of the model to air temperature, relative humidity, and precipitation input variables was examined, and the relative humidity resulted in the most sensitive response from the model. Overall, our results indicate that the EPIRICE Daily Risk Model can be used to produce potential disease risk predictions for the seasonal disease early warning service.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.27-32
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• 2003

Atmospheric and oceanic numerical models are usually initial-value and/or boundary-value problems. Change in either initial or boundary conditions leads to a variation of model solutions. Much of the predictability research has been done on the response of model behavior to an initial value perturbation. Less effort has been made on the response of model behavior to a boundary value perturbation. In this study, we use the latest version of the National Center for Atmospheric Research (NCAR) Community Climate Model (CCM3) to study the model uncertainty to tiny SST errors. The results show the urgency to investigate the second kind predictability problem for the climate models.

• Journal of Korean Academy of Nursing Administration
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• v.12 no.4
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• pp.564-573
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• 2006

Purposes: This study was to provide basic data to explain the effect of the organizational effectiveness factor on hospital nursing, to construct an appropriate model to examine the validation and relationship with variables and to provide basic data for improving the organizational effectiveness of hospital nursing. Method: This study was a descriptive correlation research. Subjects of the study were 348 nurses, 219 patients, and 89 nurses for nursing quality. Twelve measurement variables and nine paths were established in the hypothetical model. Results: The fitness indices of the model were GFI=0.91, NFI=0.90, and PGFI=0.49. Five among the nine paths proved to be statistically significant : level of nurse manpower to organizational effectiveness, conflict to organizational effectiveness, organizational climate to organizational effectiveness, level of nurse manpower to organizational climate, and leadership to organizational climate. Level of nurse manpower and leadership influenced organizational climate. Organizational climate accounted for 43% by the predictor variables, and the level of nurse manpower, conflict, and organizational climate influenced the organizational effectiveness, which accounted for 77% by the predictor variables. Conclusion: This study identified that the level of nurse manpower, leadership, conflict, and organizational climate are important factors affecting organizational effectiveness.

• The Journal of Fisheries Business Administration
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• v.46 no.3
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• pp.63-72
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• 2015

This study aims to empirically analyze the relationship between climate change elements and catch amount of coastal fisheries, which is predicted to be vulnerable to climate change since its business scale is too small and fishing ground is limited. Using panel data from 1974 to 2013 by region, we tested the relationship between the sea temperature, salinity and the coastal fisheries production. A spatial panel model was applied in order to reflect the spatial dependence of the ocean. The results indicated that while the upper(0-20m) sea temperature and salinity have no significant influence on the coastal fisheries production, the lower(30-50m) sea temperature has significant positive effects on it and, by extension, on the neighboring areas's production. Therefore, with sea temperature forecast data derived from climate change scenarios, it is expected that these results can be used to assess the future vulnerability to the climate change.

• Korean Journal of Agricultural Science
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• v.48 no.2
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• pp.311-331
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• 2021

Climate change with extreme hydrological events has become a significant concern for agricultural water systems. Climate change affects not only irrigation availability but also agricultural water requirement. In response, adaptation strategies with soft and hard options have been considered to mitigate the impacts from climate change. However, their implementation has become progressively challenging and complex due to the interconnected impacts of climate change with socio-economic change in agricultural circumstances, and this can generate more uncertainty and complexity in the adaptive management of the agricultural water systems. This study was carried out for the agricultural water supply system in Seongju dam watershed in Seonju-gun, Gyeongbuk in South Korea. The first step is to identify system disturbances. Climate variation and socio-economic components with historical and forecast data were investigated Then, as the second step, problematic trends of the critical performance were identified for the historical and future climate scenarios. As the third step, a system structure was built with a dynamic hypothesis (causal loop diagram) to understand Seongju water system features and interactions with multiple feedbacks across system components in water, agriculture, and socio-economic sectors related to the case study water system. Then, as the fourth step, a mathematical SD (system dynamics) model was developed based on the dynamic hypothesis, including sub-models related to dam reservoir, irrigation channel, irrigation demand, farming income, and labor force, and the fidelity of the SD model to the Seongju water system was checked.