• Journal of Food Hygiene and Safety
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• v.35 no.6
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• pp.552-560
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• 2020

Listeria monocytogenes is a highly pathogenic gram-positive bacterium that is easily isolated from cheese, meat, processed meat products, and smoked salmon. A zero-tolerance (n=5, c=0, m=0/25 g) criteria has been applied for L. monocytogenes in cheese meaning that L. monocytogenes must not be detected in any 25 g of samples. However, there was a lack of scientific information behind this criteria. Therefore, in this study, we conducted a risk assessment based on literature reviews to provide scientific information supporting the baseline and to raise public awareness of L. monocytogenes foodborne illness. Quantitative risk assessment of L. monocytogenes for cheese was conducted using the following steps: exposure assessment, hazard characterization, and risk characterization. As a result, the initial contamination level of L. monocytogenes was -4.0 Log CFU/g in cheese. The consumption frequency of cheese was 11.8%, and the appropriate probability distribution for amount of cheese consumed was a Lognormal distribution with an average of 32.5 g. In conclusion, the mean of probabilities of foodborne illness caused by the consumption of cheese was 5.09×10-7 in the healthy population and 4.32×10-6 in the susceptible population. Consumption frequency has the biggest effect on the probability of foodborne illness, but storage and transportation times have also been found to affect the probability of foodborne illness; thus, management of the distribution environment should be considered important. Through this risk assessment, scientific data to support the criteria for L. monocytogenes in cheese could be obtained. In addition, we recommend that further risk assessment studies of L. monocytogenes in various foods be conducted in the future.

• The Journal of the Korea Contents Association
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• v.21 no.4
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• pp.591-602
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• 2021

The purpose of this study is to compare and analyze the factors influencing happiness between the baby boom generation and the elderly generation, and to clarify the difference in the factors affecting happiness in old age. Thus, using the data of the '2019 Seoul Survey Urban Policy Indicators Survey', a total of 15,451 people including 7,831 baby boomers (born 1955-1963) and 7,620 seniors (born before 1954) were sampled. Through regression analysis, we analyzed what factors affect happiness. As a result of the analysis, family relations were the most influential factor of happiness in both groups, but next, satisfaction through participation in leisure activities for baby boomers and economic support for elderly generations had a great influence on happiness. In addition, the degree of participation in SNS, which has no effect on the baby boom generation, is a significant factor influencing happiness for the elderly, showing that participation in the digital environment is important to the elderly. In the results of this study, it was suggested that the baby boom generation and the elderly generation are significantly different in terms of group characteristics, and therefore their social needs for the pursuit of happiness in their old age should be approached differently.

• The Journal of Engineering Geology
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• v.31 no.2
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• pp.165-178
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• 2021

The influence of Soil-Water Characteristic Curve (SWCC) fitting parameters for an unsaturated natural slope was evaluated through seepage and slope stability analysis as a function of rainfall. Soil samples were collected from the study area in Jirisan National Park and the physical and mechanical characteristics of unsaturated soil layers were measured in laboratory tests. The saturation depth was calculated via seepage analysis by changing fitting parameters α, the parameter related to the Air Entry Value (AEV) and n, the parameter related to the slope of the SWCC in the range of natural conditions. Slope stability analysis using the limit equilibrium method considered the calculated depth of saturation. Results from seepage analysis for various rainfall conditions indicate the saturation depth in the soil layer suddenly increased as the fitting parameter α decreased; the saturation time for the entire soil layer also decreased. Slope stability analysis considering the calculated depth of saturation shows that the slope safety factor rapidly decreased as the fitting parameter α decreased, whereas the variation in slope safety factor was very small when n increased. Hence, fitting parameter α has a large effect on saturation depth during rainfall and therefore on slope stability, whereas slope stability is relatively unaffected by the fitting parameter n.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.245-256
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• 2021

The Fourth Industrial Revolution brought the quantitative value of data across the industry and entered the era of 'Big Data'. This is due to both the rapid development of information & communication technology and the diversity & complexity of customer purchasing tendencies. An enterprise's core competence in the Big Data Era is to analyze and utilize the data to make strategic decisions for enterprise. However, most of traditional studies on Big Data have focused on technical issues and future potential values. In addition, these studies lacked interest in managing the quality and utilization levels of internal & external customer Big Data held by the entity. To overcome these shortages, this study attempted to derive influential factors by recognizing the quality management information systems and quality management of the internal & external Big Data. First of all, we conducted a survey of 204 executives & employees to determine whether Big Data quality management, Big Data utilization, and level management have a significant impact on corporate work efficiency & corporate management performance. For the study for this purpose, hypotheses were established, and their verifications were carried out. As a result of these studies, we found that the reasons that significantly affect corporate management performance are support from the management class, individual innovation, changes in the management environment, Big Data quality utilization metrics, and Big Data governance system.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.441-452
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• 2022

Training using metacognition in a learning environment is one of the topics that have been continuously studied since the 1990s. Metacognition can be broadly divided into declarative metacognitive knowledge and procedural metacognitive knowledge (metacognitive skills). Accordingly, metacognitive training has also been studied focusing on one of the two metacognitive knowledge. The purpose of this study was to examine the role of metacognitive skills training in the context of mathematical problem solving. Specifically, the learner performed the prediction of problem difficulty, estimation of problem solving time, and prediction of accuracy in the context of a test in which problems of various difficulty levels were mixed within a set, and this was repeated 5 times over a total of 5 weeks. As a result of the analysis, we found that there was a significant difference in all three predictive indicators after training than before training, and we revealed that training can help learners in problem-solving strategies. In addition, we analyzed whether there was a difference between the experiment group and control group in the degree of test anxiety and math achievement. As a result, we found that learners in the experiment group showed less emotional and relationship anxiety at 5 weeks. This effect through metacognitive skill training is expected to help learners improve learning strategies needed for test situations.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.23-30
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• 2022

This study analyzed the effects of e-sports games on psychological well-being and life satisfaction of individuals by focusing on social and psychological aspects, recognizing e-sports games as subjective area activities based on psychological experiences as well as a means of leisure activities. To this end, 250 game users with actual experience in online games were analyzed using a structural equation modeling(SEM). The research results are as follows. First, except for other's emotion appraisal, which was a sub-factor of emotional intelligence of e-sports game users, self-emotional appraisal, use of emotion and regulation of emotion were found to have a significant positive effect on psychological well-being. Second, psychological well-being in e-sports games was found to have a significant positive relationship with life satisfaction, and psychological well-being was found to significantly mediate the relationship between emotional intelligence and life satisfaction. The findings of this study imply that managerial implications for related organizations as a platform that could support individual psychological well-being in a situation where the stress level of young adults as well as teenagers in a non-face-to-face environment is increasing.

• Journal of Broadcast Engineering
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• v.27 no.2
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• pp.244-247
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• 2022

In this paper, the performance of the decoding schemes using linear MMSE filters in the frequency and time domains and the reinforcement Gauss-Seidel algorithm for the orthogonal time frequency space (OTFS) system that can improve robustness under high-speed mobile environments are compared. The reinforcement Gauss-Seidel algorithm can improve the bit error rate performance by suppressing the noise enhancement. The simulation results show that the performance of the decoding scheme using the linear MMSE filter in the frequency domain is severely degraded due to the effect of Doppler shift as the mobile speed increases. In addition, the decoding scheme using the reinforcement Gauss-Seidel algorithm under the channel environment with 120 km/h and 500 km/h speeds outperforms the decoding schemes using linear MMSE filters in the frequency and time domains.

• Environmental and Resource Economics Review
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• v.30 no.4
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• pp.557-579
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• 2021

Collective energy is an intermediate stage in energy conversion and has a great influence on the power structure as a distributed power source. However, the problem of the collective energy business has recently emerged due to the worsening profitability of some collective energy operators. This study measured the technical efficiency of major operators through the estimation of the production efficiency of Korean collective energy operators, and based on this, we looked at ways to improve the profit structure of operators. After collecting detailed data from 16 collective energy operators between 2016 and 2019, the production efficiency of operators was estimated using the panel stochastic frontier model. As a result of the estimation, combined steam power operators showed the highest production efficiency and reverse CHP operators showed the lowest efficiency. Furthermore, as a result of examining the factors influencing profitability, it was confirmed that production efficiency has a positive effect on overall profitability. However, businesses with a high proportion of heat production, such as small district electricity operators, profitability was lower. This phenomenon is due to the structural limitations of the current heat sales market. Hence, the adjustment of the heat sales unit price is necessary to improve profitability of collective energy operators.

• Journal of Platform Technology
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• v.9 no.4
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• pp.10-31
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• 2021

The digital tax, recently referred to as the Google tax was finally agreed at the 31st General Assembly of the OECD (October 8, 2021) with full support by 136 countries and will take effect from 2023. The purpose of this study is to analyze the digital tax prepared by the OECD for global MNEs, and to suggest the impacts on the Korean industry and to present the Korean governmental countermeasures. As the first study, we analyzed the international agreement on digital tax. In results, we found that even if global MNEs do not set up a business operation in overseas countries, if sales and profits are generated, 25% of the excess profit is borne as tax (pillar 1), and when MNEs do business in all the countries, they are liable to at least a 15% tax (pillar 2). We think that countries around the world have prepared a minimum countermeasure to protect their companies in anticipation that global MNEs will easily encroach on their markets in the future. As the second study, in order to discover the reason why the MNEs are so strong, we investigated the trends of Google and B2B SaaS companies in details. In results, we discovered that the global MNEs establishes a digital platform partnership ecosystem that enables them to enter foreign markets easily and expand rapidly. In conclusion, as a countermeasure for the Republic of Korea, governmental policies were proposed at the corporate (startup nurturing), industry, and national level respectively.

• Journal of Food Hygiene and Safety
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• v.37 no.2
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• pp.107-113
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• 2022

A number of studies have been conducted to confirm the preventive effect of xylitol on dental caries as a whole or partial alternative to dietary sugars. This study reviewed the oral health effects of xylitol on the prevention mechanism of dental caries, the prevention of dental caries, the inhibition of mother-to-child transmission, and the oral health effects in the elderly based on existing studies on the oral health of xylitol. Carbohydrates and dietary sugars in food are fermented by acid-producing microorganisms in the mouth and produce dental plaque and acid, which cause dental caries. However, most dental decay-causing bacteria cannot produce acids by metabolizing xylitol. Xylitol, stored in cells as a non-metabolizable metabolite by Streptococcus mutans (S. mutans), affects bacterial glucose metabolism and inhibits bacterial growth. Xylitol consumption also reduces the amount of plaque and the population of S. mutans in both plaque and saliva. In addition, xylitol acts in the remineralization process. Xylitol has been confirmed to effectively prevent dental caries, inhibit mother-to-child transmission of MS, prevent dental caries, and increase salivary flow in the elderly. In conclusion, xylitol is an adequate sugar substitute for dental health, from infants to the elderly. For future studies, the researchers recommend reviewing the effects of xylitol on the oral and intestinal microbial environment and the side effects of excessive intake.