• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.131-141
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• 2004

For geotechnical applications, engineers use data obtained from a site investigation to interpret the structure and potential behavior of the subsurface. In most cases, these data consist of samples that represent 1/100,000 or less of the total volume of soil. These samples and associated field and lab testing provide the information used to estimate soil parameter values. The resulting values are estimated ones and there exists some likelihood that actual soil conditions are significantly different from the estimates. This may be the case even if the sampling and interpretation procedures are performed in accordance with standard practice. Although these efforts have been made to characterize the uncertainty associated with geotechnical parameters, there is no commonly accepted method to evaluate quantitatively the quality of an investigation plan as a whole or the relative significance of individual sampling points or potential sampling points.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.2
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• pp.79-84
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• 1977

In order to confirm the effect of potash top dressing and to observe the effect of N, K compound fertilizers, 17-0-17, 17-0-14, and 15-0-20, specially prepared for top dressing to rice, a field experiment with rice (Oryza Sativa L., Akibare) was conducted in a poorly drained paddy field in comparison with potassium chloride. The results obtained are as follows, 1. The effect of potash top dressing to rice was so remarkable that the yield from the plots of split application of muliate potassium or compound fertilizer was significantly higher than that from the plot received no potash at all. In contrast, the plots received all the amount of potash as one dose at transplanting time showed no significant increase in yield compared with that of potash plot. 2, The effect of N, K compound fertilizer, granulated to about the size of a small bean appeared to be so slow that it gave little increase of yield when it was appiled as a top dressing at the primodial stage, but it gave an increase of yield when it was top dressed at effective tillering stage. 3, Granular N, K compound fertilizer to be top dressed at primodial stage might be prepared in small size so that the fertilizer readily go into solution when it was applied, otherwise the fertilizer should be applied eariler than the primodial stage.

• Weed & Turfgrass Science
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• v.1 no.4
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• pp.38-43
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• 2012

This study was conducted to predict the yield response of red pepper and to determine the economic weed threshold levels for red pepper cultivation field from competition with the most serious weeds, Amaranthus patulus and Digitaria ciliaris in Youngyang of Korea. Crop yield as a function of weed density was predicted by using a rectangular hyperbola, and their economic threshold levels were determined by using the equation developed by Cousens (1987). The red pepper yield loss models of weeds were predicted as y=304.7/(1+0.063x), $R^2$=0.967 in D. ciliaris and y=281.3/(1+0.1723x), $R^2$=0.952 in A. patulus. Economic thresholds calculated using Cousens' equation were negatively related with the competitiveness of weed. Economic thresholds of each weed were calculated as 18.2 plant $100m^{-2}$ in D ciliaris, and 7.2 plant $100m^{-2}$ in A. patulus.

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.777-789
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• 2019

The purpose of this study is to evaluate changes in water quality and aquatic ecosystem health by additional dam release of stream maintenance flow from multipurpose dams in Han river basin ($34,148km^2$) using SWAT (Soil and Water Assessment Tool). The period of additional release was spring (April to June) and autumn (August to October) to evaluate the changes with the data of aquatic ecosystem health survey. The amount of additional release was set proportional to the present dam release, and the maximum release amount was controlled not to exceed the officially notified stream maintenance flow from dam. The 10 percent to 50 percent additional releases showed that the stream water quality (T-N, $NH_4$, T-P, and $PO_4-P$) concentrations except $NO_3-N$ decreased in spring while increased in autumn period. Using the stream water quality results and applying with Random Forest algorithm, the grade of aquatic ecosystem health index (FAI, TDI, and BMI) was improved for both periods especially in the downstream of basin. This study showed that the additional release of stream maintenance flow was more effective in spring than autumn period for the improvement of water quality and aquatic ecosystem.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.405-411
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• 1999

Growth responses and yields of cucumber, the populations of soil microorganisms, and the control value of nematodes were examined with six different treatments of chemical fertilizer, compost, microbial fertilizer(MF), and the combined applications of NPK + MF and compost. Cucumber, Eunseong Bakdadaki cultivar, was cultivated in the greenhouse. Higher plant height was appeared with treatments of the combined application of NPK + compost and NPK + MF compared to other treatments, especially at the early growth until 20th day after transplanting. Also, higher number of opened flowers showed with the combined treatments of NPK + compost and NPK + MF than those with others. The control value of nematodes at 60th day after transplanting with treatments of MF and NPK + MF was about 39.0% and 61.6%, respectively. The density of soil microorganisms was higher in order of actinomycetes, bacteria, and fungus. Their densities were not clearly different with treatments. Fruit yields of cucumber with treatments of NPK, compost, microbial fertilizer, and additions of compost and microbial fertilizer to NPk were higher, about 40 to 60%, than that with the control. The highest fruit yield was with NPK + MF and next highest fruit yield was with NPK + compost. It is assumed that the combined application of chemical fertilizers, compost, and microbial fertilizers would be increased the plant productivity.

• Journal of Environmental Impact Assessment
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• v.29 no.6
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• pp.453-466
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• 2020

The addition and evaluation of health impact items in Environmental Impact Assessment document are written in hygiene and public health items only for specific development projects and are being reviewed. However, after the publication of the evaluation manual on the addition and evaluation of health impact items in 2011, there is a demand for continuous methodology and improvement plans despite partial improvement. Therefore, in order to propose a methodological improvement of the evaluation manual, this technical paper identified detailed improvement requirements based on the consultation opinions on hygiene and public health items, and investigated and suggested ways to solve this problem by reviewing the contents of the research so far. As for the improvement requirements, the contents related to mitigation plan, post management, effect prediction, assessment, and present-condition investigation were presented in Environmental Impact Assessment documents for the entire development project at a frequency of 93%, 85%, 80%, 74%, and 67%, respectively. Particularly, the detailed improvement requirements related to mitigation plan consisted of an establishment direction and a management of development project. Considering the current evaluation manual and the frequency of improvement requirements, this paper proposed concrete methods or improvement plans for major methodologies for each classification of hygiene and public health items. Furthermore, a comprehensive evaluation methodology related to whether a project is implemented was proposed, which is not provided in the current assessment manual.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.400-407
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• 2021

Recently, mukbang and cookbang or cooking shows on TV and YouTube channels have increased, and the influences of these broadcasts on food consumption have been gradually increasing. There were several news articles on 'Baek Jong-won effect', in which the consumption of the agri-food Mr. Jong-won Baek mentioned on his broadcast soared, and even foods named after him are on the market. In this study, Mr. Jong-won Baek, who produces influential cooking contents through various media, was taken as a representative example. We evaluated if 'Baek Jong-won effect' exists on potato consumption, which Mr. Jong-won Baek broadcasted potato cooking recipes on TV and YouTube. After the potato recipe was broadcasted for the first time on the TV show called HomeFoodRescue, the differences in the amount of money to purchase potatoes before and after the broadcast were estimated by using the money amount to purchase data of Agri-food consumers panel and the difference-in-differences method at 6 time points (3, 6, 9, 12, 24, and 36 months). Among the time points analyzed, the potato purchases at post-broadcast were less than those at pre-broadcast. No results were observed suggesting the existence of 'Baek Jong-won effect' on potato consumption through HomeFoodRescue show in the study.

• Journal of the Korea Society of Computer and Information
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• v.28 no.3
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• pp.197-208
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• 2023

The purpose of this study is to establish definitions on Metaverse and Metaverse literacy and to develop a framework for Metaverse literacy utilizing a Delphi study and in-depth interview methods with experts on Metaverse and digital, and future education. 9 experts participated in the Delphi study and 4 took part in the in-depth interview, and Delphi study data was collected via emails from January 12th to 17th and in-depth study data was gathered via zoom from March 1st to 19th in 2022. To establish the definition of Metaverse, 6 existing definitions were presented and ranked with calculated means of each definition, and additional comments were collected. To build the definition of Metaverse literacy, 1 existing definition was shown and calculated with the degree of agreement, and additional feedback was gathered. To develop a framework for Metaverse literacy, 12 sub-concepts were presented and ranked with calculated means of each concept. After applying feedback of the Delphi study, the authors re-established the definitions of Metaverse and Metaverse literacy, and re-develop the framework for Metaverse literacy. In the in-depth interview, feedback on these definitions and the framework was collected. After these processes, the definitions of Metaverse and Metaverse literacy were finalized, and the framework for Metaverse literacy was developed. Based on the results, implications and limitations of the study, and possible future study are discussed.

• Journal of the Korea Society for Simulation
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• v.31 no.4
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• pp.23-31
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• 2022

The development of innovative technology through the 4th Industrial Revolution is actively used in the defense field. In particular, surveillance and reconnaissance capabilities using drones will be of great help to the development of military combat capabilities, such as preparing for future military personnel reductions and reinforcing alert capabilities. In this study, we analyze the combat efficiency of drones how helpful drones can be to the military operations through simulations. Drones and enemy move in the efficient shortest path within a two-dimensional space in which operational areas are mapped into number such as detection probability. Based on the detection probability of an enemy infiltrating along the path with the lowest detection probability, the detection probability change that occurs whenever a drone is additionally deployed is presented, and we analyze the combat efficiency according to the additional drone input. Simulation proves that the increase in combat efficiency decreases as more drones are added in small operational areas such as company-level operational areas. This study is expected to contribute to the efficient operation of a limited number of drones in company-level units and to help determine the most desirable quantity of drones for additional combat power improvement.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1157-1164
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• 2023

This study measures the additional dose for each treatment area using kV X-ray based OBI (On-Board Imager) and CBCT (Cone-Beam CT), which have excellent spatial resolution and contrast, and evaluates the adequacy and stability of radiation management aspects of IGRT. The subjects of the experiment were examined with OBI and CBCT attached to a linear accelerator (Clinac IX), and ring-shaped Halcyon CBCT under imaging conditions for each treatment area, and the dose at the center was measured using an ion chamber. OBI single fraction dose was measured as 0.77 mGy in the head area, 3.04 mGy in the chest area, and 7.19 mGy in the pelvic area. The absorbed doses from the two devices, Clinac IX CBCT and Halcyon CBCT, were measured to be similar in the pelvic area, at 70.04 mGy and 70.45 mGy. and in chest CBCT, the Clinac IX absorbed dose (70.05 mGy) was higher than the Halcyon absorbed dose (21.01 mGy). The absorbed dose to the head area was also higher than that of Clinac IX (9.08 mGy) and Halcyon (5.44 mGy). In kV X-ray-based IGRT, additional radiation exposure due to photoelectric absorption may affect the overall volume of the treatment area, and caution is required.