• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.3
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• pp.332-336
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• 2024

High-energy bandgap material silicon carbide (SiC) is gaining attention as a next-generation power semiconductor material, and in particular, SiC-based MOSFETs are developed as representative power semiconductors to increase the breakdown voltage (BV) of conventional planar structures. However, as the size of SJ (Super Junction) MOSFET devices decreases and the depth of pillars increases, it becomes challenging to uniformly form the doping concentration of pillars. Therefore, a structure with different doping concentrations segmented within the pillar is being researched. Using Silvaco TCAD simulation, a SJ VVD (vertical variation doping profile) MOSFET with three different doping concentrations in the pillar was studied. Simulations were conducted for the width of the pillar and the doping concentration of N-epi, revealing that as the width of the pillar increases, the depletion region widens, leading to an increase in on-specific resistance (R_on,sp) and breakdown voltage (BV). Additionally, as the doping concentration of N-epi increases, the number of carriers increases, and the depletion region narrows, resulting in a decrease in R_on,sp and BV. The optimized SJ VVD MOSFET exhibits a very high figure of merit (BFOM) of 13,400 KW/cm², indicating excellent performance characteristics and suggesting its potential as a next-generation highperformance power device suitable for practical applications.

• Journal of Internet Computing and Services
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• v.25 no.2
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• pp.79-92
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• 2024

ChatGPT, as a representative chatbot leveraging generative artificial intelligence technology, is used valuable not only in scientific and technological domains but also across diverse sectors such as society, economy, industry, and culture. This study conducts an explorative analysis of user sentiments and needs for ChatGPT by examining global social media discourse on Reddit. We collected 10,796 comments on Reddit from December 2022 to August 2023 and then employed keyword analysis, sentiment analysis, and need-mining-based topic modeling to derive insights. The analysis reveals several key findings. The most frequently mentioned term in ChatGPT-related comments is "time," indicative of users' emphasis on prompt responses, time efficiency, and enhanced productivity. Users express sentiments of trust and anticipation in ChatGPT, yet simultaneously articulate concerns and frustrations regarding its societal impact, including fears and anger. In addition, the topic modeling analysis identifies 14 topics, shedding light on potential user needs. Notably, users exhibit a keen interest in the educational applications of ChatGPT and its societal implications. Moreover, our investigation uncovers various user-driven topics related to ChatGPT, encompassing language models, jobs, information retrieval, healthcare applications, services, gaming, regulations, energy, and ethical concerns. In conclusion, this analysis provides insights into user perspectives, emphasizing the significance of understanding and addressing user needs. The identified application directions offer valuable guidance for enhancing existing products and services or planning the development of new service platforms.

• Food Science and Preservation
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• v.30 no.1
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• pp.170-178
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• 2023

We investigated the free radical scavenging and digestive enzyme inhibitory activities of the hot water extract of peach twig (Prunus persica L. Bastch). This extract of the peach twigs was further split up into n-hexane, ethyl acetate (EtOAc), and n-butyl alcohol(n-BuOH), which resulted in three solvent-soluble fractions. Free radical scavenging activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) assay systems, while hypoglycemic effect of the peach twig extract and the solvent-soluble fractions were tested using α-glucosidase and α-amylase inhibition assays. Accordingly, the EtOAc layer showed a greater free radical scavenging activity compared to other solvent-soluble fractions. Furthermore, based on the α-glucosidase and α-amylase assays, the IC₅₀ values were determined to be 38.2±1.6 and 69.6±6.1 ㎍/mL for the EtOAc-soluble fractions, respectively. Taken together, these results suggest that the fractions obtained from the peach twig extract can be considered as a potential source of natural antioxidant and hypoglycaemic constituents.

• Korean Journal of Radiology
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• v.24 no.4
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• pp.294-304
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• 2023

Objective: We aimed to investigate whether image standardization using deep learning-based computed tomography (CT) image conversion would improve the performance of deep learning-based automated hepatic segmentation across various reconstruction methods. Materials and Methods: We collected contrast-enhanced dual-energy CT of the abdomen that was obtained using various reconstruction methods, including filtered back projection, iterative reconstruction, optimum contrast, and monoenergetic images with 40, 60, and 80 keV. A deep learning based image conversion algorithm was developed to standardize the CT images using 142 CT examinations (128 for training and 14 for tuning). A separate set of 43 CT examinations from 42 patients (mean age, 10.1 years) was used as the test data. A commercial software program (MEDIP PRO v2.0.0.0, MEDICALIP Co. Ltd.) based on 2D U-NET was used to create liver segmentation masks with liver volume. The original 80 keV images were used as the ground truth. We used the paired t-test to compare the segmentation performance in the Dice similarity coefficient (DSC) and difference ratio of the liver volume relative to the ground truth volume before and after image standardization. The concordance correlation coefficient (CCC) was used to assess the agreement between the segmented liver volume and ground-truth volume. Results: The original CT images showed variable and poor segmentation performances. The standardized images achieved significantly higher DSCs for liver segmentation than the original images (DSC [original, 5.40%-91.27%] vs. [standardized, 93.16%-96.74%], all P < 0.001). The difference ratio of liver volume also decreased significantly after image conversion (original, 9.84%-91.37% vs. standardized, 1.99%-4.41%). In all protocols, CCCs improved after image conversion (original, -0.006-0.964 vs. standardized, 0.990-0.998). Conclusion: Deep learning-based CT image standardization can improve the performance of automated hepatic segmentation using CT images reconstructed using various methods. Deep learning-based CT image conversion may have the potential to improve the generalizability of the segmentation network.

• Journal of Korea Water Resources Association
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• v.57 no.6
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• pp.409-419
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• 2024

Climate change is already impacting sustainable water resource management. The influence of climate change on water supply from reservoirs has been generally assessed using climate change scenarios generated based on global climate models. However, inherent uncertainties exist due to the limitations of estimating climate change by assuming IPCC carbon emission scenarios. The decision scaling approach was applied to mitigate these issues in this study focusing on four reservoir watersheds: Chungju, Yongdam, Hapcheon, and Seomjingang reservoirs. The reservoir water supply reliablity was analyzed by combining the rainfall-runoff model (IHACRES) and the reservoir operation model based on HEC-ResSim. Water supply reliability analysis was aimed at ensuring the stable operation of dams, and its results ccould be utilized to develop either structural or non-structural water supply plans. Therefore, in this study, we aimed to assess potential risks that might arise during the operation of reserviors under various climate conditions. Using observed precipitation and temperature from 1995 to 2014, 49 climate stress scenarios were developed (7 precipitation scenarios based on quantiles and 7 temperature scenarios ranging from 0℃ to 6℃ at 1℃ intervals). Our study demonstrated that despite an increase in flood season precipitation leading to an increase in reservoir discharge, it had a greater impact on sustainable water management compared to the increase in non-flood season precipitation. Furthermore, in scenarios combining rainfall and temperature, the reliability of reservoir water supply showed greater variations than the sum of individual reliability changes in rainfall and temperature scenarios. This difference was attributed to the opposing effects of decreased and increased precipitation, each causing limitations in water and energy-limited evapotranspiration. These results were expected to enhance the efficiency of reservoir operation.

• Resources Recycling
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• v.33 no.2
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• pp.62-72
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• 2024

Although the Paris Agreement in 2015 aimed to limit global temperature increases to below 2℃ and eventually to 1.5℃ to address the climate crisis, global temperature continues to rise. Developed countries have proposed a circular economy as a major strategy to tackle this issue. Detailed implementation methods include reusing, remanufacturing, recycling, and energy recovery. Remanufacturing has a greater potential to achieve high added value and carbon neutrality than other resource circulation methods. However, currently, no standardized method for quantitatively evaluating the greenhouse gas (GHG) reduction effects of remanufacturing exists. This study compares and analyzes recent research trends since 2020 on the calculation of GHG emission reduction effects from remanufacturing. It also examines international standards for environmental impact assessment, including GHGs and environmental performance labeling systems. This study derives the key factors for standardizing the calculation of the GHG emission reduction effects of remanufactured products.

• The Journal of the Convergence on Culture Technology
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• v.10 no.1
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• pp.403-409
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• 2024

In this paper, the guidelines for the design of an Artificial Intelligence(AI) based Integrated Process Safety Management(PSM) system to enhance workplace safety using data from process safety reports submitted by hazardous and risky facility operators in accordance with the Occupational Safety and Health Act is proposed. The system composed of the proposed guidelines is to be implemented separately by individual facility operators and specialized process safety management agencies for single or multiple workplaces. It is structured with key components and stages, including data collection and preprocessing, expansion and segmentation, labeling, and the construction of training datasets. It enables the collection of process operation data and change approval data from various processes, allowing potential fault prediction and maintenance planning through the analysis of all data generated in workplace operations, thereby supporting decision-making during process operation. Moreover, it offers utility and effectiveness in time and cost savings, detection and prediction of various risk factors, including human errors, and continuous model improvement through the use of accurate and reliable training data and specialized datasets. Through this approach, it becomes possible to enhance workplace safety and prevent accidents.

• Journal of Animal Science and Technology
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• v.66 no.2
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• pp.310-325
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• 2024

Glyconutrients help in the body's cell communication. Glyconutrients and synbiotics are promising options for improving immune function. Therefore, we hypothesized that combining synbiotics and glyconutrients will enhance pig nutrient utilization. 150 pigs (Landrace × Yorkshire × Duroc), initially weighing 58.85 ± 3.30 kg of live body weight (BW) were utilized to determine the effects of synbiotics-glyconutrients (SGN) on the pigs' performance, feed efficiency, gas emission, pork traits, and composition of fatty acids. The pigs were matched by BW and sex and chosen at random to 1 of 3 diet treatments: control = Basal diet; TRT1 = Basal diet + SGN 0.15%; TRT2 = Basal diet + SGN 0.30%%. The trials were conducted in two phases (weeks 1-5 and weeks 5-10). The average daily gain was increased in pigs fed a basal diet with SGN (p = 0.036) in weeks 5-10. However, the apparent total tract digestibility of dry matter, nitrogen, and gross energy did not differ among the treatments (p > 0.05). Dietary treatments had no effect on NH₃, H₂S, methyl mercaptans, acetic acids, and CO₂ emissions (p > 0.05). Improvement in drip loss on day 7 (p = 0.053) and tendency in the cooking loss were observed (p = 0.070) in a group fed basal diets and SGN at 0.30% inclusion level. The group supplemented with 0.30% of SGN had higher levels of palmitoleic acid (C16:1), margaric acid (C17:0), omega-3 fatty acid, omega-6 fatty acid, and ω-6: ω-3 ratio (p = 0.034, 0.020, 0.025, 0.007, and 0.003, respectively) in the fat of finishing pigs. Furthermore, group supplemented with 0.30% of SGN improved margaric acid (C17:0), linoleic acid (C18:2n6c), arachidic acid (C20:0), omega 6 fatty acid, omega-6 to omega-3 ratio, unsaturated fatty acid, and monounsaturated fatty acid (p = 0.037, 0.05, 0.0142, 0.036, 0.033, 0.020, and 0.045, respectively) in the lean tissues of finishing pigs compared to pigs fed with the control diets. In conclusion, the combination of probiotics, prebiotics, and glyconutrients led to higher average daily gain, improved the quality of pork, and more favorable fatty acid composition. Therefore, these results contributed to a better understanding of the potential of SGN combinations as a feed additive for pigs.

• Journal of Ecology and Environment
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• v.48 no.1
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• pp.17-23
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• 2024

Background: Honey bees play a crucial role in pollination and ecological balance. Apis mellifera L. colonies, especially those located in specific geographic regions, such as the palm garden in Eastern Thailand, are susceptible to potential threats from microbial contaminants. Understanding and detecting microbial organisms in these beehives is essential for the preservation of bee health, honey production, and the broader ecosystem. However, the problem of microbial infection and antibiotic-resistant bacteria is more severe and continuously increasing, resulting in a health, economic, and social crisis. The purpose of this study is to determine the prevalence of microorganisms in A. mellifera beehives in palm gardens in Rayong province, Eastern Thailand. Results: Ten swabs in transport media were swabbed and obtained from different parts of each beehive (1 swab per beehive), for a total of 10 hives. Traditional microbial culture-based methods, biochemical tests, and antimicrobial susceptibility (disc-diffusion) tests were used to detect microbial organisms and antibiotic resistance in bacteria. The swab tests from nine beehives resulted in the detection of Gram-positive bacteria (63.64%), Gram-negative bacteria (27.27%), and fungi/yeast (9.09%). These microorganisms are classified as a group of coagulase-negative Staphylococcus spp. and made up 40.91% of the bacteria discovered. Other bacteria found were Coryneform bacteria (13.64%), Pantoea spp. (13.64%), Bacillus spp. (9.09%), yeast (9.09%), glucose non-fermentative Gram-negative bacilli (9.09%), and Pseudomonas spp. (4.55%). However, due to the traditional culture-based and 0biochemical tests usually used to identify the microbial organisms in clinical specimens and the limitation of identifying some environmental microbial species, the results of the antimicrobial susceptibility test cannot reveal if the organism is resistant or susceptible to the drug. Nevertheless, drug-sensitive inhibition zones were formed with each antibiotic agent. Conclusions: Overall, the study supports prevention, healthcare, and public health systems. The contamination of microorganisms in the beehives may affect the quality of honey and other bee products or even the health of the beekeeper. To avoid this kind of contamination, it is therefore necessary to wear personal protective equipment while harvesting honey and other bee products.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.2 s.54
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• pp.215-222
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• 2009

In this study, steel and FRP jackets are used to confine concrete cylinders. The FRP jacket behaviors compositely with concrete since there is bonding between them. However, the used steel jacket in this study do not behavior compositely with concrete since there is not an adhesive between them. The steel jackets are attached by external forces and the welding. This study suggests the measuring method of the axial strain for the confined concrete cylinders showing noncomposite behavior with the jackets and the correcting method of the measured strain for the composite-behavior jackets. For the noncomposite-behavior steel jacket, the axial strain of the steel surface does not represent the axial strain of the concrete inside. Also, a compressormeter can not be used. Thus, the two rigid plates at the top and bottom of a cylinder are placed and the distance of the two plates are measured and used for estimating the axial strain of the concrete. For the composite-behavior FRP jacket, the vertical strain measured on the FRP surface can be used for estimating the axial strain of the concrete. However, the vertical strain on the FRP surface contains the tensile strain due to the bulge of the concrete and, thus, the tensile strain should be corrected from the vertical strain. The corrected verticals strains compared with the measured strain or a existing constitute model; the result is satisfactory. The uncorrected stress-strain curves have the potential to under estimate the ductile behavior and the energy-dissipation-capacity of the composite-behavior FRP jackets.