• Journal of Environmental Science International
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• v.30 no.10
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• pp.803-809
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• 2021

This study aimed to investigate the effects of soil amendment (heat-expanded clay and active carbon) and planting of Dendranthema zawadskii var. latilobum on the remediation of salt-affected soil and the plant growth under high calcium chloride (CaCl₂) concentration. The experimental group comprised treatments including Non treatment (Cont.), heat-expanded clay (H), active carbon (AC), planting (P), heat-expanded clay+planting (H+P), active carbon+planting (AC+P). A 200 mL solution of CaCl₂ at a concentration of 10 g·L^-1 was applied as irrigation once every 2 weeks. Compared to the Cont., the incorporation of the 'heat-expanded clay' amendment decreased electrical conductivity of the soil leachate and cation exchange capacity, whereas the growth of Dendranthema zawadskii var. latilobum was relatively increased. These results suggest that the combination of 'heat-expanded clay' amendment and planting will mitigate negative effect of de-icing salts and improve plant growth in salt-contaminated roadside soils.

• Journal of Digital Convergence
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• v.19 no.12
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• pp.291-302
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• 2021

This study is to suggest conditions for mitigating techno-stress due to the adoption of the knowledge management system(KMS). Specifically, the study suggests that techno overload and techno complexity are negative factors on the intention to use KMS, and suggests that authentic leadership and feedback mitigate techno-stress. We conducted an online survey in May 2021 of employees in organizations that applied KMS, and obtained 417 samples. We performed the structural equation modeling of AMOS 22.0 for hypothesis testing and analyzed the main effect and the moderating effect. The result is as follows. First, techno overload and techno complexity reduced the intention to use the KMS. Second, authentic leadership increased the intention to use the KMS and mitigated techno overload and techno complexity. Third, feedback moderated the negative relationship between techno-stress and intention to use the KMS. The study has implications from the perspective of suggesting the strategic direction (authentic leadership and feedback) at the organizational level for mitigating techno-stress, which may be a problem when introducing and applying a KMS from the perspective of organization employees.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.5
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• pp.157-171
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• 2021

As smartphones spread and ICT technologies develop, taxi services have changed from hovering to platform-based calls and reservations. This has improved the mobility and accessibility of taxi users but caused problems, such as digital observing (no-responses to calls) for either short-distance services or services during the peak-demand periods. Digital Observing means ignoring and not accepting calls when they occur, which require improvement. Therefore, this study aims to derive measures to mitigate discrepancies in taxi supply and demand by adjusting the expected revenue of each taxi service using reinforcement learning based on the Taxi operation data. The results confirmed that the average complete response rate to calls would increase from 50.29% to 54.24% when incentives are applied, and an improvement of 5.86% can be achieved in short-distance sections of less than 5,000 won incentives. It is expected that the improvement will increase profitability for drivers, reduce the waiting time for passengers, and improve satisfaction with taxi services overall.

• Journal of Animal Science and Technology
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• v.63 no.4
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• pp.904-918
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• 2021

This study was conducted to investigate the effect of cooling systems on reproductive performance, body temperature, blood metabolites, and the intestinal microbiome in early gestating sows exposed to high ambient temperature. In total, 39 pregnant sows (Landrace × Yorkshire; 2 parities) were randomly assigned to and maintained in the following three treatment groups (13 sows per group) over days 0 to 35 of pregnancy: (i) air cooling (AC; 26.87 ± 1.23℃), (ii) water-drip cooling (WC; 28.81 ± 0.91℃), and (iii) a lack of cooling with heat stress (HS; 30.72 ± 0.70℃). Backfat thickness was measured before and after HS. Feces were collected on day 0 and 35 d of the trial for microbiome analysis, whereas blood was taken at day 35 of pregnancy and analyzed. Reproductive performance and physiological responses were identified at day 35. Respiration rate along with rectal and skin temperatures were lower (p < 0.05) in the AC group than in the HS and WC groups. Serum blood urea nitrogen values were increased (p < 0.05) in the WC group compared with those measured in the AC and HS groups. Triiodothyronine was found at greater levels (p < 0.05) in the AC than in the HS group. Reproductive performance was not affected by the cooling systems. At the phylum level, fecal pathogenic Spirochaete and Euryarchaeota were found in higher numbers (p < 0.05) in all groups after HS. Similarly, at the genus level, the amount of Treponema was greater (p < 0.05) in all groups after HS. In conclusion, our results suggest that AC or WC can ameliorate or mitigate the adverse effects of HS on the physiological parameters of pregnant sows reared under high temperatures.

• Journal of Animal Science and Technology
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• v.63 no.3
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• pp.640-650
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• 2021

Particulate matter (PM) produced in pig houses may contain microbes which can spread by airborne transmission, and PM and microbes in PM adversely affect human and animal health. To investigate the microbiome in PM from pig houses, nine PM samples were collected in summer 2020 inside and outside of pig houses located in Jangseong-gun, Jeollanam-do Province, Korea, comprising three PM samples from within a nursery pig house (I-NPH), three samples from within a finishing pig house (I-FPH), and three samples from outside of the pig houses (O-PH). Microbiomes were analyzed using 16S rRNA gene amplicon sequencing. Firmicutes was the most dominant phylum and accounted for 64.8%-97.5% of total sequences in all the samples, followed by Proteobacteria (1.4%-21.8%) and Bacteroidetes (0.3%-13.7%). In total, 31 genera were represented by > 0.3% of all sequences, and only Lactobacillus, Turicibacter, and Aerococcus differed significantly among the three PM sample types. All three genera were more abundant in the I-FPH samples than in the O-PH samples. Alpha diversity indices did not differ significantly among the three PM types, and a principal coordinate analysis suggested that overall microbial communities were similar across PM types. The concentration of PM did not significantly differ among the three PM types, and no significant correlation of PM concentration with the abundance of any potential pathogen was observed. The present study demonstrates that microbial composition in PM inside and outside of pig houses is similar, indicating that most microbe-containing PM inside pig houses leaks to the outside from where it, along with microbe-containing PM on the outside, may re-enter the pig houses. Our results may provide useful insights regarding strategies to mitigate potential risk associated with pig farming PM and pathogens in PM.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.5
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• pp.931-940
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• 2021

As information security(IS) is recognized as a critical success factor for organizational growth, organizations are increasing their investment in adopting and operating strict IS policies and technologies. However, when strict IS technology is adopted, IS-related techno-stress may occur in the employees who apply IS technology to their tasks. This study proposes the effect of IS-related techno-stress formed in individuals on IS policy resistance through IS strain and proves that task-technology fit mitigates the negative effect of techno-stress. Research models and hypotheses were presented through previous studies, and the secured samples were used, and structural equation modeling was applied to verify hypothesis. As a result of the study, it was confirmed that IS-related techno-stress (overload, complexity) affected IS policy resistance through IS strain (anxiety, fatigue), and that task-technology fit moderated the relationship between techno-stress and strain. This study suggests a strategic direction for improving the level of internal IS from the viewpoint of suggesting ways to mitigate the stress of employees that may occur when IS policies and technologies are adopted.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.428-438
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• 2021

For long-range communication in deep water, low carrier frequency is efficient due to a decrease in transmission loss. However, there is a limitation in that the data rate decreases due to a narrow bandwith. In order to increase the data rate in an environment with a limited bandwidth, it is necessary to design a higher-order modulation scheme. This paper analyzes the long-range communication data modulated by higher-order modulation schemes. The long-range communication experiment (23 km ~) was conducted in East Sea in October 2020. During the experiment, a vertical line array was utilized and communication sequences were modulated by Phase Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM) schemes and transmitted by a towed source. In more detail, PSK modulation consists of quadrature PSK and 8PSK, QAM modulation consists of 8QAM and 16QAM. Time reversal processing is applied to mitigate inter-symbol interference by utilizing the correlation between received signals and channel impulse responses. All modulation schemes show successful results at 23 km range, demonstrating the feasibility of higher-order modulation in long-range communication.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.9
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• pp.1220-1226
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• 2021

In this paper, we propose a probabilistic handover scheme for enhancing spectral efficiency in drone-based wireless communication systems. When a moving drone base station (DBS) provides the drone-based wireless communication service to a user equipment (UE) located on the ground, our proposed handover scheme considers the distance between DBS and UE and small scale fading. In addition, our proposed handover scheme considers a handover probability to mitigate the signalling overhead that may occur when performing frequent handovers. Through simulations for drone-based wireless communication systems, we evaluate the spectral efficiency and the handover probability of our proposed handover scheme and the conventional handover scheme. The simulation results show that our proposed handover scheme can achieve higher average spectral efficiency than the conventional handover scheme which considers only the distance between DBS and UE.

• Women's Health Nursing
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• v.27 no.3
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• pp.256-264
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• 2021

Purpose: This study investigated the impact of coronavirus disease 2019 (COVID-19) on women's health nursing clinical practicums in undergraduate nursing schools in Korea during the spring 2020 semester. Methods: A cross-sectional online survey on clinical practicum teaching experiences in the spring 2020 semester was distributed to members of the Korean Society of Women Health Nursing (KSWHN) who taught undergraduate nursing. One faculty member from each of 203 institutions was requested to respond and there were no duplicate participants. Seventy-nine participants (38.9%) responded and 74 responses were analyzed. Descriptive statistics were presented for all survey items. Results: Fifty-two faculty members (70.3%) belonged to universities and 22 (29.7%) taught at colleges. Thirty-eight (51.4%) answered that their institutions had affiliated teaching hospitals. More than half (52.7%) conducted hospital-based clinical practicums either entirely (n=20) or partially (n=19), whereas the rest of them (47.3%) conducted clinical practicums at school or home via online teaching. The typical teaching methods for offline or online education were case conferences, tests or quizzes, scenario studies, nursing skill practicums, (virtual) nursing simulations, and simulated patient education. Most of faculties (93.2%) supported the development of an educational platform to share educational materials and resources, such as case scenarios. Conclusion: Nursing faculty members utilized various teaching methods to enhance clinical skills and mitigate limited clinical exposure during the early stage of the COVID-19 pandemic. The KSWHN should move forward to develop an education platform and modalities for members who face many challenges related to the accessibility and quality of nursing education contents.

• Animal Bioscience
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• v.34 no.6
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• pp.1022-1028
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• 2021

Objective: Supplemental nitrate is known to be an effective tool to mitigate methane emission by ruminants. Based on theoretical considerations, supplemental nitrate can improve but also deteriorate the growth performance. The overall effect of supplemental nitrate on growth performance, however, is not yet known. The objective of the current study was therefore to evaluate the effect of a higher dose of NO3- on overall growth performance when feeding either Pangola grass hay or rice straw. Methods: Thirty-two crossbred, 3-month-old Thai native×Anglo-Nubian crossbred male goats were used. The experiment had a 2×2 factorial design with an experimental period of 60 days. Eight goats were randomly allocated to each dietary treatment, i.e. a ration containing either Pangola hay (Digitaria eriantha Steud) or rice straw (Oryza Sativa) as a source of roughage, supplemented with a concentrate containing either 3.2% or 4.8% potassium nitrate. The rations were formulated to be isonitrogenous. The animals were weighed at the start of the experiment and at days 30 and 60. Feces were collected during the last five days of each 30-day period. Results: High-nitrate increased overall DM intake by approximately 3%, irrespective the source of roughage, but only the goats fed a rice straw-based ration responded with an increase in body weight (BW). Thus, the overall feed conversion ratio (kg feed/kg BW gain) was influenced by roughage source ×nitrate and decreased by almost 60% when the goats were fed rice straw in combination with a high versus a low dietary nitrate content. The digestibility of macronutrients was only affected by the source of roughage and the digestibility of organic matter, crude protein, and neutral detergent fibre was greater when the goats were fed Pangola hay. Conclusion: It was concluded that the replacement of soybean meal by nitrate improves the growth performance of meat goats fed rations based on rice straw, but not Pangola hay.