• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.116-126
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• 2022

Many studies using trademark information have suggested that trademark information is good data to monitor business trends. This study intends to analyze the trend change before and after COVID-19 using trademark information. Changes before and after COVID-19 were analyzed by using goods & service classification, similar group code, and designated goods information as trademark information. Among the trademark information, it was statistically significant that the change in trends before and after COVID-19 using designated goods names. To verify the results, the changes in keywords using designated goods names before and after COVID-19 were compared with the frequency of keywords in Google Trends. Among the top 8 keywords extracted from designated goods names, the frequency of Google trend searches for 'online, antibacterial, prevention of epidemics, meal kit, virtual' is on the rise, and 'mask, droplet' is not on the rise, but it increased rapidly at the time of COVID-19, and even after COVID-19, it showed a higher level than before. The frequency of 'unmanned' does not differ much before and after COVID-19, but it has been maintained at a consistently high level, and related businesses have been active since before COVID-19, and it can be interpreted as a keyword with high public interest. This study has academic achievements in that it specifically identified information that could be used in business trends by using three types of trademark information.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.521-529
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• 2021

Background: The coronavirus disease (COVID-19) has caused changes in human activity, and these changes may possibly increase or decrease exposure to fine dust (PM_2.5). Therefore, it is necessary to evaluate the exposure to PM_2.5 in relation to the outbreak of COVID-19. Objectives: The purpose of this study was to compare and evaluate the exposure to PM_2.5 concentrations by the variation of dynamic populations before and after the outbreak of COVID-19. Methods: This study evaluated exposure to PM_2.5 concentrations by changes in the dynamic population distribution in Guro-gu, Seoul, before and after the outbreak of COVID-19 between Jan and Feb, 2020. Gurogu was divided into 2,204 scale standard grids of 100 m×100 m. Hourly PM_2.5 concentrations were modeled by the inverse distance weight method using 24 sensor-based air monitoring instruments. Hourly dynamic population distribution was evaluated according to gender and age using mobile phone network data and time-activity patterns. Results: Compared to before, the population exposure to PM_2.5 decreased after the outbreak of COVID-19. The concentration of PM_2.5 after the outbreak of COVID-19 decreased by about 41% on average. The variation of dynamic population before and after the outbreak of COVID-19 decreased by about 18% on average. Conclusions: Comparing before and after the outbreak of COVID-19, the population exposures to PM_2.5 decreased by about 40%. This can be explained to suggest that changes in people's activity patterns due to the outbreak of COVID-19 resulted in a decrease in exposure to PM_2.5.

• Safety and Health at Work
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• v.13 no.3
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• pp.263-268
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• 2022

Health care workers (HCWs) are more than ten times more likely to be infected with coronavirus infectious disease 2019 (COVID-19) than the general population, thus demonstrating the burden of COVID-19 among HCWs. Factors that expose HCWs to a differentially high-risk of COVID-19 acquisition are important to elucidate, enable appropriate public health interventions to mitigate against high risk and reduce adverse outcomes from the infection. We conducted a systematic review and meta-analysis to summarize and critically analyze the existing evidence on SARS-CoV-2 risk factors among HCWs. With no geographical limitation, we included studies, in any country, that reported (i) the PCR laboratory diagnosis of COVID-19 as an independent variable (ii) one or more COVID-19 risk factors among HCWs with risk estimates (relative risk, odds ratio, or hazard ratio) (iii) original, quantitative study design, and published in English or Mandarian. Our initial search resulted in 470 articles overall, however, only 10 studies met the inclusion criteria for this review. Out of the 10 studies included in the review, inadequate/lack of protective personal equipment, performing tracheal intubation, and gender were the most common risk factors of COVID-19. Based on the random effects adjusted pooled relative risk, HCWs who reported the use of protective personal equipment were 29% (95% CI: 16% to 41%) less likely to test positive for COVID-19. The study also revealed that HCWs who performed tracheal intubations were 34% (95% CI: 14% to 57%) more likely to test positive for COVID-19. Interestingly, this study showed that female HCWs are at 11% higher risk (RR 1.11 95% CI 1.01-1.21) of COVID-19 than their male counterparts. This article presents initial findings from a living systematic review and meta-analysis, therefore, did not yield many studies; however, it revealed a significant insight into better understanding COVID-19 risk factors among HCWs; insights important for devising preventive strategies that protect them from this infection.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.370-378
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• 2022

The purpose of this study was to investigate the factors affecting infection control practice by dental hygienist students in Jeju during clinical training amidst the COVID-19 pandemic. Online survey was conducted on 112 students and the results were statistically analyzed with frequency analysis, Student's T-test, one-way ANOVA, and regression analysis using SPSS 20.0. In the 'awareness and practice of infection control by year in college' section, 2nd year students scored significantly higher in 'cleaning and surface disinfection,' 'medical waste disposal,' and 'COVID-19 preventive measure' compared to 3rd year students. In the 'type of training institution' section, hospital setting scored significantly higher in 'cleaning and surface disinfection,' 'instrument disinfection and sterilization,' 'personal and patient protection,' and 'COVID-19 preventive measure' compared to dental clinic setting. In the 'location of institution' section, Seoul metropolitan region scored higher in 'medical waste disposal' compared to Jeju region. According to regression analysis, year in college (2nd year), type of training institution (hospital setting), location of training institution (Seoul metropolitan region), and difficulty using protective gear (no difficulty) were associated with better COVID-19 preventive measure This first study in Jeju provides an insight on the awareness and practice of infection control measures by dental hygienist students in Jeju during clinical training. Further investigation for improvement of clinical training manual is warranted.

• Economic Analysis
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• v.27 no.1
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• pp.67-90
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• 2021

This study found an interesting fact that the nonlinear relationship structure between volatility and trading volume changed before and after the COVID-19 pandemic according to empirical analysis using Bitcoin (BTC) market data that sensitively reflects investors' trading behavior. That is, their relationship appeared positive (+) in a stable market state before COVID-19 pandemic, as in theory based on the information flow paradigm. In a state under severe market stress due to COVID-19 pandemic, however, their dependence structure changed and even negative (-). This can be seen as a consequence of increased market stress caused by COVID-19 pandemics from a behavioral economics perspective, resulting in structural changes in the asset market and a significant impact on the nonlinear dependence of volatility and trading volume (in particular, their dependence at extreme quantiles). Hence, it should be recognized that in addition to information flows, psychological phenomena such as behavioral biases or herd behavior, which are closely related to market stress, can be a key in changing their dependence structure. For empirical analysis, this study performs a test of Ross (2015) for detecting a structural change, and proposes a Copula Regression Quantiles (CRQ) approach that can identify their nonlinear relationship structure and the asymmetric dependence in their distribution tails without the assumption of i.i.d. random variable. In addition, it was confirmed that when the relationship between their extreme values was analyzed by linear models, incorrect results could be derived due to model specification errors.

• The Journal of Korean Society for School & Community Health Education
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• v.24 no.1
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• pp.17-31
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• 2023

Objectives: The purpose of this study is to identify differences in fear of COVID-19 according to types of positive mental health in college students, and to verify the moderating effect of mental well-being in the relationship between mental disorders and fear of COVID-19. Methods: The results of 1,542 college students' responses to the COVID-19 Fear Scale, Korean Mental Disorder Scale, and Korean Mental Health Scale were analyzed. According to the presence of mental disorders and the level of mental well-being (high, medium, and low) of the participants which were assessed by the Korean Mental Disorder Scale and the Korean Mental Health Scale, participants were classified into five mental health groups. And the difference in fear of COVID-19 between groups was identified by one-way ANOVA. In addition, it was identified whether the moderating effect of mental well-being was significant in the relationship between mental disorders and fear of COVID-19 using hierarchical regression analysis. Results: When participants were classified by positive mental health types, the flourish group had significantly lower fear of COVID-19 than the moderate mental health group and the languishing group. The moderating effect of mental well-being was significant in the relationship between mental disorder and fear of COVID-19. Additionally, the reducing effect of mental well-being upon fear of COVID-19 was greater when the severity of mental disorder was lower. Conclusions: Basically, in the case of groups with mental disorders, efforts to reduce mental disorders should be given first and foremost. In contrast, for groups without mental disorders, psychological interventions to raise levels of mental well-being are likely to help reduce fear of COVID-19.

• Korean Journal of Radiology
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• v.22 no.11
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• pp.1875-1885
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• 2021

Objective: Central nervous system involvement in coronavirus disease 2019 (COVID-19) has been increasingly reported. We performed a systematic review and meta-analysis to evaluate the incidence of radiologically demonstrated neurologic complications and detailed neuroimaging findings associated with COVID-19. Materials and Methods: A systematic literature search of MEDLINE/PubMed and EMBASE databases was performed up to September 17, 2020, and studies evaluating neuroimaging findings of COVID-19 using brain CT or MRI were included. Several cohort-based outcomes, including the proportion of patients with abnormal neuroimaging findings related to COVID-19 were evaluated. The proportion of patients showing specific neuroimaging findings was also assessed. Subgroup analyses were also conducted focusing on critically ill COVID-19 patients and results from studies that used MRI as the only imaging modality. Results: A total of 1394 COVID-19 patients who underwent neuroimaging from 17 studies were included; among them, 3.4% of the patients demonstrated COVID-19-related neuroimaging findings. Olfactory bulb abnormalities were the most commonly observed (23.1%). The predominant cerebral neuroimaging finding was white matter abnormality (17.6%), followed by acute/subacute ischemic infarction (16.0%), and encephalopathy (13.0%). Significantly more critically ill patients had COVID-19-related neuroimaging findings than other patients (9.1% vs. 1.6%; p = 0.029). The type of imaging modality used did not significantly affect the proportion of COVID-19-related neuroimaging findings. Conclusion: Abnormal neuroimaging findings were occasionally observed in COVID-19 patients. Olfactory bulb abnormalities were the most commonly observed finding. Critically ill patients showed abnormal neuroimaging findings more frequently than the other patient groups. White matter abnormalities, ischemic infarctions, and encephalopathies were the common cerebral neuroimaging findings.

• Journal of agricultural medicine and community health
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• v.47 no.2
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• pp.109-120
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• 2022

Objectives: The purpose of this study was to identify the effectiveness of COVID-19 vaccinations on deaths of the COVID-19 cases in some elderly long-term care facilities (LTCF) in Gwangju Metropolitan City. Methods: The study subjects were 659 COVID-19 cases in residents of 7 elderly LTCF, Gwangju, from 21 Dec. 2021 to 28 Jan. 2022. The used variables were confirmed dates for COVID-19, demographic characteristics, co-morbidities, presentation of symptoms, death and vaccination related characteristics including type of vaccine, doses and dates. Vaccination status were classified as not vaccinated, partially and fully vaccinated. The associations of vaccination status and deaths of COVID-19 cases were tested by chi-square test and multiple logistic regression analysis. Results: The rates of not vaccinated, partially vaccinated and fully vaccinated were 19.4%, 10.2% and 70.4%, respectively. The mortality rate of the cases was 6.4%. The death rate by vaccination status was 16.4% in not vaccinated, 15.4% in partially vaccinated and 2.6% in fully vaccinated, showing a statistically significant difference. The adjusted odds ratios (ORs) (95% confidence intervals, CIs) of death compared to fully vaccinated were 7.64 (3.87-16.34) in non-vaccinated, and 6.97 (3.44-14.14) in partially vaccinated. Conclusions: COVID-19 vaccination seems to work effectively in preventing deaths of COVID-19 cases of elderly LTCF residents. This finding support that fully vaccinations in high risk group such as elderly LTCF residents is very important for one of strategies of COVID-19 management.

• The Journal of the Korea Contents Association
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• v.21 no.9
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• pp.149-163
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• 2021

The 4th industrial revolution refers to the next-generation industrial revolution led by information and communication technologies such as artificial intelligence (AI), Internet of Things (IoT), robot technology, drones, autonomous driving and virtual reality (VR) and it also has made a significant impact on the development of the advertising industry. However, the world is rapidly changing to a non-contact, non-face-to-face living environment to prevent the spread of COVID 19. Accordingly, the role of the 4th industrial revolution and advertising is changing. Therefore, in this study, text analysis was performed using Big Kinds to examine the 4th industrial revolution and changes in advertising before and after COVID 19. Comparisons were made between 2019 before COVID 19 and 2020 after COVID 19. Main topics and documents were classified through LDA topic model analysis and Word2vec, a deep learning technique. As the result of the study showed that before COVID 19, policies, contents, AI, etc. appeared, but after COVID 19, the field gradually expanded to finance, advertising, and delivery services utilizing data. Further, education appeared as an important issue. In addition, if the use of advertising related to the 4th industrial revolution technology was mainstream before COVID 19, keywords such as participation, cooperation, and daily necessities, were more actively used for education on advanced technology, while talent cultivation appeared prominently. Thus, these research results are meaningful in suggesting a multifaceted strategy that can be applied theoretically and practically, while suggesting the future direction of advertising in the 4th industrial revolution after COVID 19.

• The Korean Journal of Applied Statistics
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• v.36 no.5
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• pp.447-455
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• 2023

COVID-19 is an emerging infectious disease that is hard to predict in terms of fatality rate, treatments, and the timing of its end. World is developing treatments and vaccines for COVID-19. Several treatments and vaccines currently have emergency use authorization, but the treatments are only allowed for critically ill patients with COVID-19. Therefore, the aim of this study is to analyze the confirmed cases of COVID-19, including mortality and testing, in OECD countries and to assess the effect of vaccination on mortality. Looking at the confirmed cases, mortality, and vaccination rates of COVID-19, the number of confirmed cases was lower than previously reported cases after full vaccination. In early 2022, with Omicron, the confirmed cases increased sharply, while mortality dropped, and the mortality showed a gentle curve as the cumulative fully vaccinated exceeded 50%. This indicates that COVID-19 vaccines have an effect on reducing mortality. However, the duration of effectiveness of vaccines was considerably short, which decreased the initial inoculation effect and increased the monthly mortality. As this study was carried out during the COVID-19 pandemic, there was not enough data to analyze comprehensively. However, it is meaningful to compare and analyze the impact of COVID-19 by country.