• Journal of Information Technology Applications and Management
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• v.29 no.3
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• pp.1-23
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• 2022

This study is about the change in the importance of shopping value for beauty products of social commerce due to the social crisis or risk caused by COVID-19. It was analyzed focusing on whether the importance of shopping value changed before and after COVID-19. We checked the importance of shopping value after COVID-19 through the AHP results of previous papers before COVID-19, and analyzed the importance by adding variables of risk reduction behavior and delivery convenience according to the situation of COVID-19. The AHP method was used to check the change in the importance of shopping value before and after COVID-19, and the study was conducted using 48 data. The results were as follows. As for the importance of shopping value of social commerce beauty products, it was ranked in the order of time convenience, convenience of delivery, third-ranked trust business operators, fourth-ranked economic aspects, fifth-ranked decision support, sixth-ranked risk reduction behavior, and seventh-ranked business reputation. Compared to previous studies, decision-making support, which was in the second place, fell to the fifth place. This result was confirmed to be a drop in ranking due to the improvement of delivery convenience due to the influence of COVID-19. In addition, in the case of beauty products, it was confirmed that risk reduction behavior related to COVID-19 infection is not a key factor in shopping value. These results confirmed changes in the importance of shopping value compared to pre-COVID-19 studies, and in the case of product groups other than beauty products, further studies are expected as there is a possibility of other results.

• Journal of information and communication convergence engineering
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• v.20 no.3
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• pp.219-225
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• 2022

In this study, we propose training a support vector machine (SVM) model on top of deep networks for detecting Covid-19 from chest X-ray images. We started by gathering a real chest X-ray image dataset, including positive Covid-19, normal cases, and other lung diseases not caused by Covid-19. Instead of training deep networks from scratch, we fine-tuned recent pre-trained deep network models, such as DenseNet121, MobileNet v2, Inception v3, Xception, ResNet50, VGG16, and VGG19, to classify chest X-ray images into one of three classes (Covid-19, normal, and other lung). We propose training an SVM model on top of deep networks to perform a nonlinear combination of deep network outputs, improving classification over any single deep network. The empirical test results on the real chest X-ray image dataset show that deep network models, with an exception of ResNet50 with 82.44%, provide an accuracy of at least 92% on the test set. The proposed SVM on top of the deep network achieved the highest accuracy of 96.16%.

• Pediatric Infection and Vaccine
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• v.31 no.1
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• pp.83-93
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• 2024

Purpose: Since the start of the coronavirus disease 2019 (COVID-19) pandemic, various variants of concern have emerged. We divided the representative COVID-19 mutation period into four waves and aimed to analyze the clinical and laboratory features of children with COVID-19 from pre-mutation wave to the middle of omicron wave. Methods: We retrospectively reviewed the medical records of hospitalized patients aged ≤19 years with laboratory confirmed COVID-19. Clinical and laboratory findings during pre-mutation (February 1st 2020 to September 30th 2020), alpha/beta (October 1st 2020 to May 31st 2021), delta (June 1st 2021 to October 31st 2021), and omicron (November 1st 2021 to May 31st 2022) waves were compared. Results: Among total 827 patients, 163 (19.7%) were asymptomatic, and the frequency of fever and cough was 320 (38.7%) and 399 (48.2%), respectively. The proportion of fever ≥38.5℃ was observed to be high during the omicron wave in the age group under 12 years. Lymphopenia was observed highly in the omicron wave in the age group under 12 years, and in the delta wave in the age group older than 12 years. Neutropenia was highly observed in the delta wave in the 0-4 years age group. Conclusions: There were distinct characteristics during all epidemic waves of COVID-19. Children with COVID-19 had more frequent persistent fever during delta wave and children during the omicron wave had a higher peak fever.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.943-952
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• 2021

The purpose of this study is to evaluate the effect of COVID-19 on corporate governance attributes and firm performance association. This research used a sample of 188 non-financial firms from the Malaysian market for the years 2019-2020. We found that the COVID-19 has affected all firm characteristics including firm performance, governance structure, dividend, liquidity, and leverage level, yet, the difference between prior and post COVID-19 pandemic is not significant. Also, the investigation revealed that board size exerts a significant positive impact on firm performance. After splitting the sample based on year, however, we found that board size does not matter in the uncertain time of the current crisis, while board diversity appeared to be significantly enhancing firm performance in the crisis time compared to the prior year where it has an inverse association with firm performance in both indicators. Board meetings and audit committee meetings seemed to have a significant negative influence on firm performance pre and post-COVID-19. This study contributes to the limited literature by providing the first empirical evidence on the impact of Coronavirus on the firm performance and corporate governance association.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.2
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• pp.169-175
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• 2022

Unexpected events, such as the COVID-19 pandemic, can occur at any time and have an influence on all countries. The COVID-19 pandemic has infected more than 200 nations, including Indonesia. As a result of this phenomenon, Indonesia's state revenue system will need to be adjusted. Therefore, the goal of this research is to see if there are any differences in taxation in Indonesia as a result of the COVID-19 incident. The data was collected using the base years of 2018, 2019, and 2020. The information came from the financial statements of companies in the industrial sector that are publicly traded on the Indonesian Stock Exchange (IDX). Purposive sampling was used, and there were 54 companies represented in the samples that met the criterion. In this study, the difference test was used as an analytical technique. According to the findings, there was no difference in the pattern of tax avoidance between pre-COVID-19 in 2019 and during the COVID-19 period in terms of leverage and fixed asset intensity. It occurred because the tax avoidance policy was implemented as a short-term fiscal strategy to ensure the company's existence. Finally, because these findings were restricted to the Indonesian environment, their generalizability was limited.

• The Korean Journal of Food And Nutrition
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• v.36 no.4
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• pp.222-235
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• 2023

In this research, we examined the shifts in determinants influencing the frequency of eco-friendly food purchases pre- and post-COVID-19. Our analysis utilized filtered 2019-2021 Consumption Behavior Survey data from the Korea Rural Economic Institute Food, excluding any irrational responses. Given the nature of the dependent variable, a multinomial logistic regression model was employed with demographic factors, variables pertaining to food consumption behavior, and variables concerning food consumption awareness as predictors. Following the onset of the COVID-19 pandemic, an individual's level of education was observed to positively influence the frequency of eco-friendly food purchases. In contrast, income level and fluctuations in food consumption expenditure did not appear to have a discernible impact on the purchasing frequency of such eco-friendly products. Irrespective of the advent of COVID-19, variables such as the frequency of online food purchases, the utilization of early morning delivery services, dining out frequency, and the intake of health-functional foods consistently demonstrated a positive correlation with the propensity to purchase eco-friendly foods. Overall, consumers prioritizing safety, quality, and nutrition over price, taste, and convenience in their procurement decisions for rice, vegetables, meat, and processed foods exhibit an increased inclination toward the acquisition of eco-friendly food products.

• Journal of Information Technology Services
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• v.20 no.6
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• pp.45-62
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• 2021

After the COVID-19 outbreak in 2019, the spread of COVID-19 has not been easily caught despite preventive measures in each country. The spread of COVID-19 has hit the world, especially in the economic and tourism sectors. Countries around the world are easing restrictions on the movement of vaccinated people in preparation for the post-corona era. Under the name of "Vaccine Passport," "Vaccination Certificate," and "Digital Health Pass," vaccination measures are being implemented to allow vaccination recipients to use multi-use facilities. However, there is no international agreement on the movement of countries, and each country has its own immigration policy. In order to return to pre-corona daily life, global agreements must be reached from the movement of vaccinated people between countries, and standards and implementation methods must be determined. This study focuses on the implementation and utilization of vaccination certificates suitable for the COVID-19 era. We will look at the spread of COVID-19 and its international response policies. In the case of COVID-19, we will investigate why vaccination certificate installation should be standardized and how far the current standardization has been discussed, and discuss the characteristics of vaccination certificate installation and considerations. In order for the immunization certificate discussed in the previous chapter to be recognized internationally, institutional and technical considerations are identified and security factors that may occur in each implementation are also presented. Finally, the international recognition case of vaccination certificate is discussed, and the method of installation and utilization of vaccination certificate is proposed. This paper can be used as a policy because of its timeliness in studying the standards of vaccination certificates and considerations for international recognition to restore movement between countries in the spread of COVID-19. In addition, if other infectious diseases occur in the future or similar cases where movement between countries is restricted, it can be used as a reference to support the movement of verified people.

• Asia-Pacific Journal of Business
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• v.15 no.2
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• pp.143-157
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• 2024

Purpose - This paper aims to analyze the relationship and correlation between the stock markets of Korea, the US, China, and Japan before and after the outbreak of COVID-19. Design/methodology/approach - This study conducted an empirical analysis using the stock market data from January 2016 to June 2023 for the representative market indices of Korea, the US, China, and Japan. The analysis employed the VAR model, Granger causality test, impulse response function, and variance decomposition. Findings - Analyzing the relationships of these stock markets before and after the outbreak of COVID-19, we obtained the following results. (i) The influence of the U.S. stock market was found to be absolute regardless of the COVID-19 period, and the rise in the U.S. stock market led to rises in other stock markets. (ii) The Chinese stock market had a significant negative impact on the U.S., Korean, and Japanese stock markets before COVID-19, but this influence disappeared after COVID-19. This suggests that the Chinese market exhibited unique characteristics different from the global market after COVID-19. (iii) Analyzing the period excluding the first quarter of 2020, when global stock market volatility was extremely high due to the spread of COVID-19, we found that the results were very similar to the analysis including the first quarter of 2020. Therefore, it is difficult to argue that the increased uncertainty during this period distorted the relationships among the stock markets of these four countries. Research implications or Originality - We anticipate that these findings will offer valuable insights for both individual and institutional investors, aiding them in portfolio diversification and risk mitigation.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.195-207
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• 2022

COVID-19 has remained one of the most serious health crises in recent history, resulting in the tragic loss of lives and significant economic impacts on the entire world. The difficulty of controlling COVID-19 poses a threat to the global health sector. Considering that Artificial Intelligence (AI) has contributed to improving research methods and solving problems facing diverse fields of study, AI algorithms have also proven effective in disease detection and early diagnosis. Specifically, acoustic features offer a promising prospect for the early detection of respiratory diseases. Motivated by these observations, this study conceptualized a speech-based diagnostic model to aid in COVID-19 diagnosis. The proposed methodology uses speech signals from confirmed positive and negative cases of COVID-19 to extract features through the pre-trained Visual Geometry Group (VGG-16) model based on Mel spectrogram images. This is used in addition to the K-means algorithm that determines effective features, followed by a Genetic Algorithm-Support Vector Machine (GA-SVM) classifier to classify cases. The experimental findings indicate the proposed methodology's capability to classify COVID-19 and NOT COVID-19 of varying ages and speaking different languages, as demonstrated in the simulations. The proposed methodology depends on deep features, followed by the dimension reduction technique for features to detect COVID-19. As a result, it produces better and more consistent performance than handcrafted features used in previous studies.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.33 no.4
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• pp.113-121
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• 2022

Objectives: This study aimed to compare the quality of life (QoL) of children with attention-deficit/hyperactivity disorder (ADHD) before and during coronavirus disease-2019 (COVID-19) and to examine how their QoL is affected by emotional and environmental factors during COVID-19. Methods: Participants in the pre-COVID-19 (n=43) and COVID-19 (n=36) groups were recruited from the same university hospital. The Pediatric Quality of Life Inventory (PedsQL) 4.0 Child Self-report, the Children's Depression Inventory (CDI), the Revised Children's Manifest Anxiety Scale (RCMAS), the PedsQL 4.0 Parent Proxy Report, and the Conners' Parent Rating Scale (CPRS) were employed. Independent t-tests, Pearson's correlation analysis, and multiple regression analysis were conducted. Results: Caregivers assessed the children's QoL more negatively than the children themselves in both groups. Children with ADHD evaluated their physical function more negatively and anxiety was significantly higher in the COVID-19 group. In the COVID-19 group, the PedsQL child self-report was significantly predicted by the CPRS, the CDI, and environmental factors (i.e., relation to child and monthly household income). Conclusion: Children with ADHD in the COVID-19 group had a numerically lower QoL and significantly higher anxiety. To improve QoL, it is important to deal with not only depression but also ADHD symptoms and environmental factors.