• Nuclear Engineering and Technology
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• 제51권6호
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• pp.1708-1714
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• 2019

The purpose of the critical evaluation of the spent fuel pool (SFP) is to verify that the maximum effective multiplication factor ($K_{eff}$) is less than the critical safety limit at 100% stored condition of the spent fuel with the maximum reactivity. At nuclear power plants, the storage standard of spent fuel, ie, the loading curve, is established to prevent criticality from being generated in SFP. Here, the loading curve refers to a graph showing the minimum discharged burnup versus the initial enrichment of spent fuel. Recently, US NRC proposed the new critical safety assessment guideline (DSS-ISG-2010-01, Revision 0) of PWR SFPs and most of utilities in US is following it. Of course, the licensed criterion of the maximum effective multiplication factor of SFP remains unchanged and it should be less than 0.95 from the 95% probability and the 95% confidence level. However, the new guideline is including the new evaluation methodologies like the application of the axial burnup profile, the validation of depletion and criticality code, and trend analysis. Among the new evaluation methodologies, the most important factor that affects $K_{eff}$ is the axial burnup profile of spent fuel. US NRC recommends to consider the axial burnup profiles presented in NUREG-6801 in criticality analysis. In this paper, criticality effect was evaluated considering three profiles, respectively: i) Axial burnup profiles presented in NUREG-6801. ii) Representative PWR axial burnup profile. iii) Uniform axial burnup profile. As the result, the case applying the axial burnup profiles presented in NUREG-6801 showed the highest $K_{eff}$ among three cases. Therefore, we need to introduce a new methodology because it can be issued if the axial burnup profiles presented in NUREG/CR-6801 are applied to the domestic nuclear power plants without any other consideration.

• 한국항행학회논문지
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• 제23권2호
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• pp.114-124
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• 2019

2016년 1월 다보스포럼에서 발표된 4차 산업혁명에 대한 다양한 기술 적용 분야의 하나로서 무인비행장치인 드론 시장은 미래의 교통체계의 커다란 변화와 관련된 중요한 분야로 급속하게 확대 발전되고 있다. 한국의 경우 드론에 대한 관심은 국가자격증의 폭발적인 수요로 연계되고 있으며 드론조종자 수도 2015년 400여명에서 2018년 기준 17,000여명을 초과하면서 교육환경과 안전의 중요성이 강조되고 있다. 따라서 본 연구에서는 드론교육 현황과 함께 교육환경 평가를 위해 설계된 DREEM(Dundee ready educational environment measure) 모형에 근거하여 조종자의 안전의식을 분석하였다. 연구결과 교육 환경에 대한 만족도가 절차 준수를 포함한 전반적인 안전의식에 영향을 주므로 이에 대한 개선이 요구된다는 결론을 도출하였다.

• 한국터널지하공간학회 논문집
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• 제21권1호
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• pp.155-166
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• 2019

주요 도심지 도로건설은 포화상태로 지하공간의 개발이 필요하며 이를 위해 지하철도와 지하 도로 터널의 건설은 활발히 진행되어 왔다. 국외의 경우 지하 도로터널을 2층구조로 활용하는 복층터널 시공이 이루어 졌으며 이에 따른 지하공간 개발 기술이 높은 수준에 이르고 있다. 2차로 병설터널을 2차로 복층터널로 계획하는 경우 굴착 면적은 크게 차이가 나지 않으며, 터널 통과구간이 차지하는 폭을 대폭 줄일 수 있다. 이를 통해 터널 통과구간이 차지하는 폭을 대폭 감소시킬 수 있으므로 지반조건이 불량한 경우 필요한 상부 보강 비용을 절감할 수 있다. 본 연구에서는 복층터널 굴착에 따른 영향에 대해 알아봄으로써 지하공간 활용 기술을 높이고 단층터널 굴착영향과 비교를 통해 향후 복층터널 설계 및 안정성 평가에 도움이 될 수 있을 것으로 기대된다.

• Journal of Ginseng Research
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• 제45권1호
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• pp.108-118
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• 2021

Background: Korean ginseng (Panax ginseng Meyer) contains a variety of ginsenosides that can be metabolized to a biologically active substance, compound K. Previous research showed that compound K could be enriched in the red ginseng extract (RGE) after hydrolysis by pectinase. The current study investigated whether the enzymatically hydrolyzed red ginseng extract (HRGE) containing a notable level of compound K has cognitive improving and neuroprotective effects. Methods: A scopolamine-induced hypomnesic mouse model was subjected to behavioral tasks, such as the Y-maze, passive avoidance, and the Morris water maze tests. After sacrificing the mice, the brains were collected, histologically examined (hematoxylin and eosin staining), and the expressions of antioxidant proteins analyzed by western blot. Results: Behavioral assessment indicated that the oral administration of HRGE at a dosage of 300 mg/kg body weight reversed scopolamine-induced learning and memory deficits. Histological examination demonstrated that the hippocampal damage observed in scopolamine-treated mouse brains was reduced by HRGE administration. In addition, HRGE administration increased the expression of nuclear-factor-E2-related factor 2 and its downstream antioxidant enzymes NAD(P)H:quinone oxidoreductase and heme oxygenase-1 in hippocampal tissue homogenates. An in vitro assay using HT22 mouse hippocampal neuronal cells demonstrated that HRGE treatment attenuated glutamate-induced cytotoxicity by decreasing the intracellular levels of reactive oxygen species. Conclusion: These findings suggest that HRGE administration can effectively alleviate hippocampus-mediated cognitive impairment, possibly through cytoprotective mechanisms, preventing oxidative-stress-induced neuronal cell death via the upregulation of phase 2 antioxidant molecules.

• Journal of Information Science Theory and Practice
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• 제10권4호
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• pp.66-86
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• 2022

The main aim of this study is to identify the role of information dissemination on urban and rural citizens of Bangladesh during the COVID-19 pandemic and the role of misinformation in this process. The study also aimed at finding appropriate counter misinformation strategies regarding COVID-19. An online questionnaire was prepared to collect the viewpoints of the urban and rural citizens of Bangladesh regarding dissemination of information during COVID-19, misinformation regarding COVID-19, and counter misinformation strategies. Along with demographic and general information, a five-point Likert scale was used to measure COVID-19 related misinformation beliefs and how to counter them. Chi square tests were used to determine the association between current residency, information sources, the importance of information dissemination, reactions after getting COVID related information, and evaluative steps after getting information and before disseminating it. Additionally, nonparametric Mann-Whitney U and Kruskal-Wallis tests were conducted to know the significance of difference in respondents' assessment on COVID-19 related misinformation in terms of their demographic characteristics. Cronbach's alpha score was obtained to see the reliability of the questionnaire items. The current study reveals that both urban and rural citizens of Bangladesh are influenced by information dissemination regarding COVID-19 and they have lower level of misinformation belief. The respondents have differences in misinformation belief by different demographic groups. Respondents' educational status, information literacy, sources of getting information, and evaluative steps after getting information have significant differences in misinformation belief. The study also noticed the support of respondents for countering misinformation strategies regarding COVID-19.

• 한국농공학회논문집
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• 제63권2호
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• pp.1-10
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• 2021

Agricultural reservoirs have a great influence on the water circulation in the watershed. It is necessary to evaluate the impact on water circulation by the agricultural reservoir. Therefore, in this study, we simulated the agricultural watershed through linkage of Hydrological Simulation Program Fortran (HSPF) and Module-based hydrologic Analysis for Agricultural watershed (MASA) and evaluated the contribution of the agricultural reservoir to water circulation by watershed water circulation index. As a result of simulating the Idong reservoir watershed through the HSPF-MASA linkage model, the model performance during the validation period was R2 0.74 upstream, 0.78 downstream, and 0.76 reservoir water level, respectively. To evaluate the contribution of agricultural reservoirs, three scenarios (baseline, present state, and present state without reservoir) were simulated, and the water balance differences for each scenario were analyzed. In the evaluation through the agricultural water circulation rate in the watershed, it was found that the water circulation rate increased by 1.1%, and the direct flow rate decreased by 13.6 mm due to the agricultural reservoir. In the evaluation through the Budyko curve, the evaporation index increased by 0.01. Agricultural reservoirs reduce direct runoff and increase evapotranspiration, which has a positive effect on the water circulation.

• 대한영양사협회학술지
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• 제28권3호
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• pp.205-217
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• 2022

School meals are prepared based using the HACCP system, which is designed to ensure the physical and mental health of students. However, operational recommendations in school cafeterias have changed due to COVID-19 and include delays in serving time to restrict the number of meals and the installation of screens to prevent droplet transmission. Unfortunately, these changes may have detrimentally affected hygiene practices and generated new food poisoning sources. This study aimed to determine the hygiene state of school cafeterias in the Gyeongnam area from December 2020 to September 2021 based on the monitoring of total aerobic and coliform bacteria. Kitchen floors were the most contaminated areas with an average number of total aerobic bacteria of 4.3 log CFU/100 cm², whereas counts in dining areas were relatively low at 0.1~3.5 log CFU/100 cm². Newly installed partitioned areas had the lowest contamination level of 0.1~2.8 log CFU/100 cm². Escherichia coli was not detected on any surface, while coliform was detected on workbenches and floors. In conclusion, hygienic practices appear to have been adequately managed in school cafeterias despite COVID-19 driven changes. Nonetheless, continuous monitoring is recommended to ensure prompt response to changing environments.

• 한국콘텐츠학회논문지
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• 제22권3호
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• pp.1-16
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• 2022

현재 AI의 기술력은 과거 인간만이 가진 능력을 초월할 정도로 빠르게 발전하고 있다. 머지않은 미래, 앞으로 인간과 AI는 메타버스 사회 구성원으로서 서로 영향을 주고받게 될 것으로 예측된다. 이에 본 연구에서는 메타버스에서 AI와 인간이 공생하게 될 시대, 인간이 스스로 존엄성을 지켜가며 행복한 삶을 추구하며 살아갈 수 있는 핵심 역량으로써 공감의 중요성을 강조하였다. 본 연구는 메타버스 내 컴퓨터 매개 커뮤니케이션이 대두되는 사회적 성격을 반영하여, '디지털휴먼공감지표(DHEI)'를 개발하였다. 본 연구는 총 1,100명을 대상으로 설문을 수행하고, 탐색적 요인분석과 확인적 요인분석을 수행하여, 총 7개의 요인, 28개 문항을 도출하였다. DHEI는 관점수용, 자기/타인 인식, 사회체계 장벽의 문맥적 이해, 영향력 가늠, 연대적 노력, 평화 추구, 기기 인격화로 구성되었다. 본 연구의 결과는 공감에 대한 새 기준을 제시하며 미래인재교육의 방향 설정에 기여할 것으로 기대된다.

• 산업융합연구
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• 제21권1호
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• pp.103-110
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• 2023

본 연구는 우리나라 중소기업의 인더스트리 4.0의 성숙도, 클러스터링의 지표 요인, 주요 요인이 기업의 자체 평가에 미치는 영향을 알아보기 위해 클러스터링 분석을 수행하였다. 80개의 국내 중소기업을 4가지 범주로 분류하면 프로세스, 기술 및 조직 간에 유의미한 양의 상관관계가 있음을 발견하였다. 또한, 성숙도 모델에 따라 테스트된 80개 기업의 대다수는 아직 미성숙하거나 부분적으로 성숙한 것으로 보이며 인더스트리 4.0과 관련된 혁신 전략의 많은 개선과 재평가가 필요한 것으로 나타났다. 마지막으로, 싱가포르 스마트 산업 준비 지수는 국내 중소기업에서 자체 평가를 수행하는 데 적합하다는 결론을 도출하였다. 이러한 결론은 실무자와 연구자에게 유용한 성숙도 및 그룹화 지침으로 제공될 수 있다.

• 여성건강간호학회지
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• 제28권1호
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• pp.46-55
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• 2022

Purpose: This study aimed to determine the level of postpartum posttraumatic stress disorder (PTSD) and postpartum depression (PPD) in Korean mothers with healthy babies and to explore the factors related to postpartum PTSD. Methods: This study used a longitudinal survey design to explore the levels and association of PPD and PTSD. Two hundred women were recruited during pregnancy and the data were collected via online survey from 166 mothers (84% retained) who gave birth to healthy babies, at two postpartum periods: Fear of childbirth was assessed at the 1st week; and spousal support, PPD, and postpartum PTSD were surveyed at the 4th week postpartum. Descriptive statistics, t-test, one-way analysis of variance, Chi square test, and multiple regression were done. Results: The mean age of mothers was 33.12 (±3.97) years old. Postpartum PTSD was low (8.95±6.49) with 1.8% (n=3) at risk (≥19). PPD was also low (6.68±5.28) and 30.1% (n=50) were identified at risk (≥10). The comorbid rate of PPD with PTSD was 6%. Mothers who did not have a planned pregnancy had higher scores of PPD (t=-2.78, p=.008), whereas spousal support and PPD had negative relationship (r=-.21, p=.006). The overall explanatory power for postpartum PTSD was 55.2%, of which PPD was the only significant variable (β=. 76, t=13.76, p<.001). Conclusion: While only 1.8% was at risk of postpartum PTSD at 4 weeks postpartum, PPD prevalence was 30.1% and PPD was the only influential factor of postpartum PTSD. Assessment and counseling of PPD are required as well as screening for postpartum PTSD. More research is also needed on postpartum PTSD in Korean women.