• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.949-965
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• 2023

In this study, we propose a method to monitor the surface area of agricultural reservoirs in South Korea using Sentinel-1 synthetic aperture radar images and the deep learning model, Swin Transformer. Utilizing the Google Earth Engine platform, datasets from 2017 to 2021 were constructed for seven agricultural reservoirs, categorized into 700 K-ton, 900 K-ton, and 1.5 M-ton capacities. For four of the reservoirs, a total of 1,283 images were used for model training through shuffling and 5-fold cross-validation techniques. Upon evaluation, the Swin Transformer Large model, configured with a window size of 12, demonstrated superior semantic segmentation performance, showing an average accuracy of 99.54% and a mean intersection over union (mIoU) of 95.15% for all folds. When the best-performing model was applied to the datasets of the remaining three reservoirsfor validation, it achieved an accuracy of over 99% and mIoU of over 94% for all reservoirs. These results indicate that the Swin Transformer model can effectively monitor the surface area of agricultural reservoirs in South Korea.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.213-229
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• 2023

This study aimed to investigate the effects of beak trimming and crossbreeding-combinations on the productive performance and stress response levels of Korean native chickens. The study divided 248 individuals from six crossbreeding-combinations into two groups: one underwent beak trimming, and the other did not. The survival rate, body weight, egg production rate, egg quality, feather damage score, HSP-70 gene expression level, H/L ratio, and intracellular DNA damage rate were measured and analyzed. The results showed that the beak-trimmed group had significantly higher survival rates and hen-housed egg production compared to the non-beak-trimmed group (P<0.05). Feather damage and DNA damage rates were significantly lower in the beak-trimmed group (P<0.05). On the other hand, there were no significant differences between the two groups in adult body weight, hen-day egg production, egg quality, HSP-70 gene expression level, and H/L ratio. Among the crossbreeding-combinations, there were significant differences in survival rate, body weight, feather damage score, egg quality, and DNA damage rate (P<0.05), while egg production rate, HSP-70 gene expression level, and H/L ratio showed no significant differences. There was an interaction between beak trimming and crossbreeding-combinations in some traits. In conclusion, beak trimming in Korean native chickens has a positive impact on productive performance, and in terms of stress response, beak trimming may not act as a stress factor or may even reduce stress after the growing period. Furthermore, there were differences in productive performance and stress response levels among crossbreeding-combinations, but the effects of beak trimming were similar across these combinations.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.981-992
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• 2023

Due to recent global climate change, the scale of flood damage is increasing as rainfall is concentrated and its intensity increases. Rain on a scale that has not been observed in the past may fall, and long-term rainy seasons that have not been recorded may occur. These damages are also concentrated in ASEAN countries, and many people in ASEAN countries are affected, along with frequent occurrences of flooding due to typhoons and torrential rains. In particular, the Bandung region which is located in the Upper Chitarum River basin in Indonesia has topographical characteristics in the form of a basin, making it very vulnerable to flooding. Accordingly, through the Official Development Assistance (ODA), a flood forecasting and warning system was established for the Upper Citarium River basin in 2017 and is currently in operation. Nevertheless, the Upper Citarium River basin is still exposed to the risk of human and property damage in the event of a flood, so efforts to reduce damage through fast and accurate flood forecasting are continuously needed. Therefore, in this study an artificial intelligence-based river flood water level forecasting model for Dayeu Kolot as a target station was developed by using 10-minute hydrological data from 4 rainfall stations and 1 water level station. Using 10-minute hydrological observation data from 6 stations from January 2017 to January 2021, learning, verification, and testing were performed for lead time such as 0.5, 1, 2, 3, 4, 5 and 6 hour and LSTM was applied as an artificial intelligence algorithm. As a result of the study, good results were shown in model fit and error for all lead times, and as a result of reviewing the prediction accuracy according to the learning dataset conditions, it is expected to be used to build an efficient artificial intelligence-based model as it secures prediction accuracy similar to that of using all observation stations even when there are few reference stations.

• Korean Journal of Plant Resources
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• v.37 no.1
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• pp.87-92
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• 2024

'Miha' is a new strawberry (Fragaria x ananassa Duch.) cultivar, which was released by the Highland Agriculture Research Institute in 2019. The 'Miha' cultivar originates from a 2014 cross between 'Monterey' and 'Saebong No. 3', both of which exhibited excellent ever-bearing characteristics, including continuous flowering and large fruits under long-day and high temperature conditions. This new cultivar was initially named 'Saebong No. 12' after examining its characteristics and productivity during summer cultivation between 2015 and 2019. After regional adaptability tests, 'Miha' was selected from 'Saebong No. 12' as an elite cultivar. The general characteristics of 'Miha' include intermediate, elliptic leaves, and strong growth. The fruits are conical and of a dark-red color. The number of leaves of 'Miha' was 21.9, which was 6.2 fewer than that of the control cultivar, 'Goha' with 28.1. The number of flower clusters of 'Miha' was similar to that of 'Goha'. The average fruit weight of 'Miha' was 13.4 g, which was 4.3 g heavier than that of 'Goha'. The fruit hardness of 'Miha' was 36.2 g·mm^-2, which was 10.1 g·mm^-2 harder than that of 'Goha'. The marketable yield of 'Miha' was 37,393 kg·ha^-1, 156% more than that of 'Goha' with 23,970 kg·ha^-1. Therefore, the new cultivar of ever-bearing strawberry 'Miha' is expected to be very popular in the export or bakery market because it is hard.

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.279-294
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• 2024

Large-scale civil engineering structures such as dams require a systematic approach to jointed rock-mass grouting to prevent water leakage into the foundations and to ensure safe operation. In South Korea, rock grouting design often relies on the experience of field engineers that was gained in similar projects, highlighting the need for a more systematic and reliable approach. Rock-mass grouting is affected mainly by hydrogeology and the presence of discontinuities, involving factors such as the rock quality designation (RQD), joint spacing (Js), Lugeon value (Lu), and secondary permeability index (SPI). This study, based on data from field investigations of 14 domestic sites, analyzed the correlation between hydrogeological factors (Lu and SPI), discontinuity characteristics (RQD and Js), and grout take, and systematically established a design method for rock grouting. Analysis of correlation between the variables RQD, Js, Lu, and SPI yielded Pearson correlation (r) values as follows: Lu-SPI, 0.92; RQD-Lu, -0.75; RQD-Js, 0.69; RQD-SPI, -0.65; Js-Lu, -0.47; and SPI-Js, -0.41. The grout take increases with Lu and SPI values, but there is no significant correlation between RQD and Js. The proposed approach for grouting design based on SPI values was verified through analysis and comparison with actual curtain-grouting construction, and is expected to be useful in practical applications and future studies.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.4
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• pp.187-194
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• 2023

Purpose: A mismatched size in the post and post space is a common problem during post-fixation. Since this discordance affects the bonding strength of the fiber-reinforced composite resin post (FRC Post), a corresponding luting agent is required. The aim of this study was to evaluate the bonding strength of the FRC post according to the fitness of the fiber post and the type of luting agent. Materials and Methods: Thirty mandibular premolar were endodontic-treated and assigned to two groups according to their prepared post space: Fitting (F) and Mismatching (M). These groups were further classified into three subgroups according to their luting agent: RelyX Unicem (ReX), Luxacore dual (Lux), and Duolink (Duo). A push-out test was performed to measure the push-out bond strengths. The fractured surfaces of each cross-section were then examined, and the fracture modes were classified. Results: In the ReX and Duo subgroups, the F group had a higher mean bond strength; however, the Lux subgroup had no significant difference between the F and M groups. In the analysis of the failure modes, the ReX subgroup had only adhesive failures between the cement and dentin. Conclusion: The result of this study showed that the bond strength of an FRC post was influenced by the type of luting agent and the mismatch between the diameter of the prepared post space and that of the post.

• Journal of Food Hygiene and Safety
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• v.39 no.1
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• pp.16-25
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• 2024

This study investigated the prevalence of Campylobacter spp. In poultry meat and its association with foodborne illnesses in Gwangju, South Korea. It was found that out of the 307 samples of poultry meat examined, 111 (36.2%) were infected with Campylobacter spp. Among the isolated strains, 102 were identified as Campylobacter jejuni and 14 as Campylobacter coli. The detection rate of Campylobacter spp. was higher in duck meat (63.1%) than in chicken meat (26.0%). In 5 samples (1 chicken, 4 duck), both Campylobacter jejuni and Campylobacter coli were found together. The antimicrobial resistance test showed that 99 strains were resistant to more than one antimicrobial. The most common antimicrobial resistance was seen against ciprofloxacin (84.5%), followed by nalidixic acid (82.8%), tetracycline (44.0%), and gentamicin (2.6%). The isolated Campylobacter spp. were serotyped and the results showed the presence of HS2 (20 strains), HS15 (11 strains), HS19 (9 strains), and HS8 (8 strains). Considering the findings, it is recommended to maintain hygienic practices during the cooking process and to take necessary precautions to prevent the spread of pathogenic bacteria.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.431-437
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• 2023

This study evaluated the ecological characteristics related to spike heading time of three Korean foxtail millet cultivars, i.e., one early and two late maturities, and a finger millet cultivar in the north-central region of the Korean Peninsula, Kangwon Province. The changes in heading time occurred due to the changes in planting time from mid-May to late June. The heading time of the early-maturity cultivars was early August, with 80 days required for heading (DH) for the mid-May planting; late August, with 65 DHs for the late June planting; and mid-late August, with 100 DHs and mid-October, with 65 DHs, respectively, for the late-maturity cultivars. The accumulated temperature at heading time ranged from 1,700℃ of mid-May planting to 1,500℃ of late June planting in the early-maturity cultivars. In contrast, it ranged from 2,100℃ to 1,900℃ in the late-maturity cultivars. The photoperiod at heading time ranged from 14.0 h to 13.2 h in the early-maturity cultivars, whereas it was from 13.2 h to 12.5 h in the late-maturity cultivars. Considering that the limiting heading time of Korean foxtail millet and finger millet in the northern region of Kangwon Povince is late August, the limiting accumulated temperature at the heading time was evaluated to be approximately 1,500℃ and 2,000℃ for early and late-maturity cultivars, respectively. The mean daily temperature from planting to heading time showed a negative correlation with the DH, which was shortened with the increase in mean daily temperature. This suggests that delaying the planting time from May to June in the north-central region of the Korean Peninsula increases the mean daily temperature during vegetative growth periods, resulting in the decrease of the DH and the accumulated temperature.

• Journal of The Korean Society of Grassland and Forage Science
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• v.44 no.2
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• pp.64-70
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• 2024

The experiment was conducted to determine the changes in seed productivity of Italian ryegrass (Lolium multiflorum Lam.) according to nitrogen fertilization levels in the southern region of Korea. Italian ryegrass (IRG) variety 'Green Call' was sown in the fall of 2021 in Jinju, Gyeongsangnam-do. The experiment consisted of three nitrogen fertilizer levels (100, 120, and 140 N kg/ha) with three replications using a randomized complete block design. Harvesting was done approximately 30 days after heading on May 18th. There was no difference in heading date among treatments, which occurred on April 18th. The longest IRG was observed in the 140 N kg/ha treatment, but there was no significant difference. No significant differences were observed in lodging, disease resistance, and cold tolerance among treatments, but lodging was severe in all treatments. The length of the spike averaged 44.95 cm, with no difference among treatments, and the number of seeds per spike was highest in the 120 N kg/ha treatment. Seed yield increased with increasing nitrogen fertilizer levels, averaging 3,707 kg/ha (as-fed basis). DM content of seed and straw averaged 76.95% and 62.19%, respectively, with no significant differences among treatments. The remaining straw after harvesting averaged 6,525 kg/ha on a dry matter basis, with the highest value observed in the 140 N kg/ha treatment. Overall, considering the results, the optimal nitrogen fertilizer application rate for seed production of Italian ryegrass in the southern region when sown in autumn was found to be 120 N kg/ha.

• Journal of The Korean Society of Grassland and Forage Science
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• v.44 no.2
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• pp.118-126
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• 2024

This study was conducted in Cheonan, the middle region of South Korea, to evaluate the forage characteristics of six medium maturing Italian ryegrass varieties: 'Kowinmaster', 'IR 601', 'IR 602', 'IR 603', 'IR 604' and 'IR 605'. In growth characteristics, 'Kowinmaster' exhibited the earliest heading date on April 30, while 'IR 601' exhibited the latest on May 17. 'IR 601' exhibited the highest lodging resistance, and all varieties demonstrated excellent disease resistance, waterlogging tolerance, and cold tolerance. 'IR 603', 'IR 604', and 'IR 605' demonstrated above-average plant length, with 'IR 604' reaching the longest at 114.8 cm. In productivity, 'IR 602' and 'IR 605' produced the highest total dry matter yield, each exceeding 12,800 kg/ha. Regarding feed values, 'Kowinmaster' recorded the highest RFV and TDN at 119.18 and 66.07%, respectively, with 'IR 605' exhibiting the second highest. 'IR 604' and 'IR 601' demonstrated crude protein concentrations over 9%, with 'IR 604' exhibiting the highest at 9.74%. Analysis of monosaccharide content in Italian ryegrass revealed that 'IR 605' exhibited the highest glucose and fructose content at 23.35 g/kg and 50.70 g/kg, respectively. In summary, 'IR 602' exhibited the highest productivity, 'Kowinmaster' recorded the highest feed value, and 'IR 605' exhibited the highest glucose and fructose content. Therefore, 'IR 605' is considered the most outstanding variety due to its superior productivity, second highest feed value, and significant monosaccharide content.