• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1053-1064
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• 2022

The Thiessen method, which is the current area average precipitation method, has serious structural limitations in accurately calculating the average precipitation in the watershed. In addition to the observation accuracy of the precipitation meter, errors may occur in the area average precipitation calculation depending on the arrangement of the precipitation meter and the direction of the heavy rain. When the watershed is small and the station density is sparse, in both simulation and observation history, the Thiessen method showed a peculiar tendency that the average precipitation in the watershed continues to increase and decrease rapidly for 10 minutes before and after the peak. And the average precipitation in the Thiessen basin was different from the rainfall radar at the peak time. In the case where the watershed is small but the station density is relatively high, overall, the Thiessen method did not show a trend of sawtooth-shaped over-peak, and the time-dependent fluctuations were similar. However, there was a continuous time lag of about 10 minutes between the rainfall radar observations and the ground precipitation meter observations and the average precipitation in the basin. As a result of examining the ground correction effect of the rainfall radar watershed average precipitation, the correlation between the area average precipitation after correction is rather low compared to the area average precipitation before correction, indicating that the correction effect of the current rainfall radar ground correction algorithm is not high.

• Korean Journal of Food Science and Technology
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• v.54 no.4
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• pp.445-454
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• 2022

This study aimed to improve the physiological activity of onion juice via lactic acid bacterial fermentation. Seven types of lactic acid bacteria were used for the fermentation of onion juice. The pH and sugar content of the onion juice decreased, while its titratable acidity increased after lactic acid bacteria fermentation, and the cell count of lactic acid bacteria was 7.31-10.40 log CFU/mL. The total free sugar content decreased, while the total organic acid content increased in the fermented onion juice. Quercetin content of the fermented juice was 0.13-0.53 mg/kg. The total polyphenol and flavonoid contents increased after fermentation. Additionally, the 2,2-diphenyl-1-picryl-hydrazyl-hydrate free radical and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) radical cation scavenging activities were increased by fermentation. Overall, lactic acid bacteria fermentation of onion juice enhanced its physiological activity. Based on these findings, Bifidobacterium breve KCTC 3441 was selected as the onion juice fermentation strain.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.30-47
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• 2022

This study analyzed the characteristics of cold air flow according to spatial types in urban areas of Changwon-si, Gyeongsangnam-do. The spatial types were classified by cluster analysis considering the land use map, building information, and topographic characteristics produced on the Changwon biotope map. The amount of cold air and wind speed were derived by KLAM_21 modeling. As a result, spatial types were classified into a total of 14 types considering the density and height of buildings, land use types, and topographic characteristics. Cold air flow was found to generate cold air in the valley of the forest area outside urban area, move through roads and open spaces, and accumulate in the low-lying national industrial complex, and then spread cold air throughout the urban areas. There was a lot of cold air flow in the tall building area, and the cold air accumulation was less in the slope and ridge areas. The results of this study were able to understand the characteristics of cold air flow according to building density, land use type, and topography, which will be usefully used as basic data for urban wind road construction to mitigate climate and improve air quality in urban areas.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.6
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• pp.231-238
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• 2022

To secure the mechanical strength of porous Al₂O₃ ceramics, which can be utilized for filters and catalyst supports is essential for their functionality and durability. Superior mechanical strength would be obtained by tailoring the densification and grain growth during sintering. This study deals with grain growth behavior of a freeze-casted Al₂O₃ with addition of La₂O₃. In a temperature range between 1400 and 1600℃, variations of average grain size with sintering time and temperature were observed and analyzed with G_tⁿ-G₀ⁿ = kt and with k = k₀exp(-E_a/RT). As a result, n value and activation energy (E_a) for grain growth were calculated as 3 and 489.09 kJ/mol, respectively. These commonly confirms retardation effect of the La addition during sintering of Al₂O₃ porous structure. More accurate analysis on the La effect can be followed to provide useful guidance for the selection of additives for better mechanical strength in Al₂O₃ porous structures.

• Journal of Environmental Impact Assessment
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• v.31 no.1
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• pp.63-74
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• 2022

In orderto understand the urban thermal conditions, many studies have been conducted to estimate the thermal fluxes. Currently sensible heat fluxes are estimated through various methods, but studies about comparing the differences between each method are very insufficient. Therefore, this study try to estimate the sensible heat flux of the same area by two representative estimation methods and compare their results to confirm the significance and limitation between methods. As a result of the study, the heat balance methods has a great advantage in terms of resolution but it can not consider the anthropogenic heat flux, so sensible heat flux can be underestimated in urban areas. When estimating based on physical equation, anthropogenic heat flux can be considered and the error is relatively small, it has a limitations in time and space resolutons. The two methods showed the largest difference in industiral areas where anthropogenic heat fluxes are high, with an average of 135 W/m² and a maximum of 400 W/m². On the other hand, the green and water have a very small difference with and average of 20 W/m². The results between two methods show significant differences in urban areas, it is necessary to select a suitable method for each research purpose.

• Geophysics and Geophysical Exploration
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• v.25 no.2
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• pp.59-70
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• 2022

Recent studies demonstrate that machine learning has expanded in the field of seismic interpretation. Many convolutional neural networks have been developed for seismic sequence identification, which is important for seismic interpretation. However, expense and time limitations indicate that there is insufficient data available to provide a sufficient dataset to train supervised machine learning programs to identify seismic sequences. In this study, patch division and data augmentation are applied to mitigate this lack of data. Furthermore, to obtain spatial information that could be lost during patch division, an artificial channel is added to the original data to indicate depth. Seismic sequence identification is performed using a U-Net network and the Netherlands F3 block dataset from the dGB Open Seismic Repository, which offers datasets for machine learning, and the predicted results are evaluated. The results show that patch-based U-Net seismic sequence identification is improved by data augmentation and the addition of an artificial channel.

• Journal of the Korean Society of Earth Science Education
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• v.15 no.2
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• pp.142-157
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• 2022

Heuristic is a empirical method that is used quickly when uncertainty or insufficient time and information are insufficient. The purpose of this study is to find out what heuristics appear in the processing of the experimental manual among science experiment activities of elementary school students. To do this, 20 fifth-grade elementary school students (female 10 and male 10) were required to conduct scientific experimental activities as research participants to collect experimental behavior data and gaze movement data, and retrospective interviews were conducted. The collected data extracted and conceptualized behavior by heuristics. As a result of the study, there were five heuristics that appeared in the processing of the experimental manual: "reducing the difference between the target state and the current state," "guessing the experimental procedure," "paying attention to the expected results," "comparing with the picture of the experimental manual," and "using a trial and error strategy." According to each concept of heuristics, there were favorable and unfavorable aspects for experimental activities. In science experiment activities that students experience for the first time, there is a lack of information and the situation is uncertain, so behavior by heuristics appears in nature. Therefore, educators need to understand students' heuristics and guide scientific experimental activities.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.783-789
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• 1997

This study was conducted to identify leakage of fluorescent substances out of 56 crops and to develop sorting methods of nonviable seeds of Chinese cabbage. Fluorescent substances were detected from 36 species, Chinese cabbage, radish, broccoli, cauliflower, egg plant and rape seed etc. In Chinese cabbage, the germination rate of non-sorted seeds decreased rapidly with ageing of seeds at 45$^{\circ}C$ and 100％. After Chinese cabbage seeds soaked for 4hrs and coated with cellulose, the sorting ratio of non fluorescent seeds were decreased 91.3％ to 1.7％ by increasing ageing periods from control to 8 days, while fluorescent seeds were increased drastically from 8.7％ to 98.3％. Also, incubation of water soaked dead seeds of Chinese cabbage treated with 0.5-1.0％ ninhydrin and 0.01N sodium thiosulfate for 30~60 minutes at 35$^{\circ}C$ developed purple color.

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.189-200
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• 2023

As urbanization and industrialization increase development in downtown areas, damage due to ground settlement continues to occur. Building collapse in urban has a high risk of leading to large-scale damage to life and property. However, there has rarely been studied on measurement data analysis methods when uneven loads are applied to the excavated ground and no prior knowledge of the ground. Accordingly, it was attempted to analyze the relative settlement behavior and correlation by processing the time-series surface settlement of construction sites in the urban. In this paper, the average index of difference in settlement and average of relative difference in settlement are defined and calculated, then plotted in the coordinate system to analyze the relative settlement behavior over time. In addition, since there was no prior knowledge of the ground, a standard to classify the clusters was needed, and the observation points were classified into using k-means clustering and Dunn Index. As a result of the analysis, it was confirmed that all the clusters moved to the stable region as the settlement amount converges. The clusters were segmented. Based on the analysis results, it was possible to distinguish between the independent displacement area and same behavior area by analyzing the correlation between measurement points. If possible to analyze the relative settlement behavior between the stations and classify the behavior areas, it can be helpful in settlement and stability management, such as uplift of the surrounding area, prediction of ground failure area, and prevention of activity failure.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.6
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• pp.146-164
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• 2022

Recently, the Korean government promoted the construction of metropolitan express subway to connect major transportation hub in the metropolitan area within 30 minutes. Most stations of the metropolitan express subway are connected to existing subway stations, so the importance of transfer increased. Although many studies have been conducted on the effect of transfer penalty on route choice, there are few studies on the transfer behavior of the metropolitan express subway. Therefore, in this study, a transfer behavior analysis was conducted on the Shinbundang Line, a representative metropolitan express subway. To analyze the transfer behavior according to the degree of traffic congestion and the presence of fare payment, route choice models were made using transport card data divided according to week, time, and user characteristics. As a result of the analysis, users of the metropolitan express subway had greater disutility to the transfer waiting time compared to the transfer moving time. Furthermore, especially during the peak time, EIVM(Equivalent in-vehicle minutes) of the transfer waiting time was 3.51. In this study, EIVM for metropolitan express subway users were analyzed to be 2.6 minutes, which is significantly lower than the results of previous studies on subways. This suggests that there is a difference in the transfer penalty between subways and metropolitan express subway, and that it is necessary to apply the transfer penalty between subways and express subway differently when forecasting subway traffic demand.