• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.543-553
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• 2023

This study was conducted to propose a simple method to evaluate the load-carrying capacity of RC slab bridges, which have been most frequently constructed in Korea. A number of RC slab bridges have been considerably deteriorated associate with the long service year. However, since these bridges are not included in the 1st and 2nd class infrastructures due to their short span length, they have been relatively neglected compared to other bridge types in terms of safety management. In the previous theoretical study, a process (draft) was proposed for evaluating the damage of RC slab bridges using the relationship between the displacement response ratio and the stiffness reduction rate derived by the measured displacement and natural frequency. In this paper, to verify the validity of the proposed damage evaluation process (draft), the results to the actual bridges were compared with the safety grade and the Matsui's deterioration index. In addition, to enhance the practical applicability of the existing process (draft), an improved method approximately evaluating the load-carrying capacity using only the measured natural frequency was presented. If an error of 10% of the load-carrying capacity is allowed, it is judged that the proposed damage evaluation process can be appropriately used not only for evaluating the safety of RC slab bridges, but also for determining priorities for their maintenance.

• Health Policy and Management
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• v.33 no.3
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• pp.243-252
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• 2023

This paper aims to introduce Korea's total current health expenditure (CHE) and National Health Accounts of the year 2021 and their 2022 preliminary figures constructed on the basis of the System of Health Accounts 2011. As CHE includes expenditures for prevention, tracking, and treatment of coronavirus disease 2019 (COVID-19) and compensation for losses to medical institutions from 2020, the details are also introduced. Korea's total CHE in 2021 is 193.3 trillion won, which is 9.3% of gross domestic product (GDP). The preliminary figure in 2022, 209.0 trillion won, exceeded the 200 trillion won line for the first time, and its "ratio to GDP" of 9.7% is expected to exceed the average of Organisation for Economic Co-Operation and Development member countries for the first time. Korea's health expenditures, which were well controlled until the end of the 20th century, have increased at an alarming rate since the beginning of the 21st century, threatening the sustainability of national health insurance. The increase in health expenditure after 2020 is partly due to a temporary increase in response to COVID-19. However, when considering the structure of Korea's health insurance price hike, where the ratchet effect of increased medical expenses works particularly strongly, it is unlikely that the accelerating growth trend that has lasted for more than 20 years will stop easily. More aggressive policies to control medical expenses are required in the national health insurance which not only constitutes the main financing sources of the Korean health system but also has the most powerful policy means in effect for changes in the health care provision.

• Journal of The Korean Association For Science Education
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• v.43 no.2
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• pp.181-190
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• 2023

In this study, we compared discourse by environments for using tools in terms of participation types, discourse types, and knowledge building processes. 24 first-year high school students were divided into six groups. They were assigned to the sharing tools environment, which used one marker and one smart device, or the individual tools environment, which used markers and smart devices individually. Students participated in small group learning using AR application based on the concept of chemical bonding. All classes were video- and audio-taped. Semi-structured interviews were conducted with six students who voluntarily agreed. The results of the study revealed that the sharing tools environment had a high proportion of one-student dominating type, while the individual tools environment had a high proportion of partly participating type and most students participating type. In the individual tools environment, the ratio of knowledge sharing and knowledge construction discourse was similar compared to the tool sharing environment, and the sub-discourse types were also diverse. In the sharing tools environment, only some students had a meaningful knowledge building process. On the other hand, in the individual tools environment, most of the group members constructed knowledge about the target concept, and had a meaningful knowledge building process. In addition, the misconceptions that appeared to some group members were corrected through small group discussions.

• Journal of the Korean Society for information Management
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• v.39 no.1
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• pp.91-117
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• 2022

The number of depressed patients in Korea and around the world is rapidly increasing every year. However, most of the mentally ill patients are not aware that they are suffering from the disease, so adequate treatment is not being performed. If depressive symptoms are neglected, it can lead to suicide, anxiety, and other psychological problems. Therefore, early detection and treatment of depression are very important in improving mental health. To improve this problem, this study presented a deep learning-based depression tendency model using Korean social media text. After collecting data from Naver KonwledgeiN, Naver Blog, Hidoc, and Twitter, DSM-5 major depressive disorder diagnosis criteria were used to classify and annotate classes according to the number of depressive symptoms. Afterwards, TF-IDF analysis and simultaneous word analysis were performed to examine the characteristics of each class of the corpus constructed. In addition, word embedding, dictionary-based sentiment analysis, and LDA topic modeling were performed to generate a depression tendency classification model using various text features. Through this, the embedded text, sentiment score, and topic number for each document were calculated and used as text features. As a result, it was confirmed that the highest accuracy rate of 83.28% was achieved when the depression tendency was classified based on the KorBERT algorithm by combining both the emotional score and the topic of the document with the embedded text. This study establishes a classification model for Korean depression trends with improved performance using various text features, and detects potential depressive patients early among Korean online community users, enabling rapid treatment and prevention, thereby enabling the mental health of Korean society. It is significant in that it can help in promotion.

• Journal of The Korean Association For Science Education
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• v.43 no.2
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• pp.87-98
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• 2023

In this study, we investigated the change in science core competency perception of high school students and the reason for change when science inquiry classes were conducted using eight 'skills' of the 2015 revised science curriculum. Fifteen first-year high school students in Jeollanam-do participated in the science inquiry class of this study, and the class was conducted for 20 hours (5 hours a day for four days). The inquiry activities used in the class consisted of four activity stages (research problems, research methods, research results, and conclusions) and each stage was constructed to include at least one 'skill (Problem Recognition, Model Development and Use, Inquiry Design and Performance, Data Collection, Analysis and Interpretation, Mathematical Thinking and Computer Application, Conclusion and Evaluation, Evidence-based Discussion and Demonstration, and Communication)'. As a result of the study, students' perception of the five science core competencies increased statistically significantly at the significance level of 0.01 through inquiry classes and more than 93% of students recognized that their science core competencies improved through the classes. However, since the class of this study was conducted for a small number of students, it is difficult to generalize the effect of the class, and so it is necessary to conduct a quantitative study for many students.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.487-494
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• 2023

In this study, performance comparison was performed on R and TensorFlow, which are free deep learning tools. In the experiment, six types of deep neural networks were built using each tool, and the neural networks were trained using the 10-year Korean temperature dataset. The number of nodes in the input layer of the constructed neural network was set to 10, the number of output layers was set to 5, and the hidden layer was set to 5, 10, and 20 to conduct experiments. The dataset includes 3600 temperature data collected from Gangnam-gu, Seoul from March 1, 2013 to March 29, 2023. For performance comparison, the future temperature was predicted for 5 days using the trained neural network, and the root mean square error (RMSE) value was measured using the predicted value and the actual value. Experiment results shows that when there was one hidden layer, the learning error of R was 0.04731176, and TensorFlow was measured at 0.06677193, and when there were two hidden layers, R was measured at 0.04782134 and TensorFlow was measured at 0.05799060. Overall, R was measured to have better performance. We tried to solve the difficulties in tool selection by providing quantitative performance information on the two tools to users who are new to machine learning.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.315-321
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• 2008

Recently, in the light of environments and utilization, countermeasures to preserve beaches in coastal area are required without depending on such as jetties and breakwaters. The necessity of integrated sand management including not only coastal sediment but also sediment discharge from hinterland rivers is increased so as to establish long-term counterplan for sediment transport. In this regard, the following subjects are examined in this study; efficient ways for discharged sand to be transported from a river to the neighboring coast, the river terrace occurrence and its growth at the river delta, measures to improve storage efficiency of the discharged sand and measures to prevent the sand resources from being discharged into the deep sea during flooding. In recent, A jetty of 260 m length was constructed at Namdae River mouth in the year of 2005 as a countermeasure against the occurrence of sand-bar at river mouth and its close. In this study, a series of numerical experiments were carried out to investigate the characteristics of sediment transport and morphological change due to the construction of jetty at the entrance of Namdae River mouth. Firstly, The sand discharge from Namdae River is quantified by one-dimensional numerical analysis assuming the mixed sand of three different particle diameters. Then, in order to understand the transport behavior of the sand discharge from river and river mouth phenomena the numerical experiments were then conducted to examine the flow behaviors of river efflux and wind generated circulations in coastal area. And, after establishing the numerical model system, which predicts the sea bed changes obtained from the flux model combining with the wave propagation, wave-induced currents and sediment transport models, the sediment transport in the vicinity of Namdae River mouth is analyzed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.69-78
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• 2006

The rainfall depth-area-duration analysis which is used to characterize precipitation extremes for specification of so-called design storms, provides a basis for evaluation of drought severity when storm depth is replaced by an appropriate measure of drought severity. So we propose a method for constructing drought severity-area-duration curves in this study. Monthly precipitation data over the whole Korea are used to compute SPI. Such SPIs are abstracted to several independent spatial components from EOF analysis. Using Kriging method, these spatial components are used to constitute grid-based SPI data set over the whole Korea including Jeju island with $6km{\times}6km$ resolution. After identifying main drought events, the drought severity-area-duration curves for these events over 32-year period of record are finally constructed. As a result, such curves show the similar shape with storm-based curves in the sense that the drought severity (or rainfall depth) is inversely proportional to drought area from the curves, but drought-based curves are different from storm-based curves in the sense that the drought severity decreasing rate with respect to drought area is much less than depth decreasing rate.

• Journal of Korea Port Economic Association
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• v.39 no.3
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• pp.107-122
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• 2023

This study aims to analyze the effect of reducing air pollutant emissions of the ship fuel oil sulfur content regulation policy, which has been gradually introduced for three years. In addition, the emission reduction effect of VSR and AMP was also analyzed. The analysis was conducted on NOx, CO, VOC, SOx, TSP, PM10, and PM2.5, which are provided by EEA, and the spatial scope of the analysis was conducted on Incheon Port, which is located in the metropolitan area of Korea and has a large ripple effect on air pollution. Three scenarios were constructed for analysis. Scenario 1: If there is no policy, Scenario 2: If only fuel oil sulfur content regulation was implemented, Scenario 3: The analysis was conducted by reflecting fuel oil sulfur content regulation, VSR, and AMP. As a result of the analysis, in the case of scenario 1, 4,801 tons, 4,932 tons, and 5,144 tons of air pollutants were emitted during the three-year period. In Scenario 2, 4,219 tons, 4,152 tons, and 3,989 tons were discharged, and in Scenario 3, 4,198 tons, 4,138 tons, and 3,973 tons were discharged. The findings of this study are anticipated to be applied as fundamental research in port air environment management and Incheon Metropolitan City air management.

• Journal of Service Research and Studies
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• v.13 no.4
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• pp.70-96
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• 2023

Recently, the high turnover rate of nursing staff and the problems caused by increased job stress have been highlighted as social issues, and the problem of 'Taeoom' in nursing organizations has received increasing attention. Therefore, the purpose of this study is to propose a solution to the Taeoom problem, including bullying in the nursing work environment, as there is an urgent need to find a solution to prevent and overcome this problem. For this purpose, based on the S-O-R framework and previous studies, job stress and turnover intention were derived as outcome variables of Taeoom and communication competence as an antecedent factor, and a research model was constructed with the expectation that mindfulness and social support would serve as moderating variables to help overcome this problem. Data were collected through a survey of 300 nurses who had experienced Taeoom within the past year, and the hypotheses were tested using a structural equation model. The results revealed that the higher the communication competence of nurses, the less they perceived the damage of Taeoom, and that the damage caused by Taeoom leads to turnover intention through high job stress. In addition, mindfulness and social support significantly attenuated the positive effects of burnout on job stress and job stress on turnover intention, respectively. The significance of this study is that it proposed an extended P-S-O-R framework by adding a prevention stage to the existing S-O-R framework, and further tested the moderating effects of mindfulness and social support variables. It is expected that the findings of this study will provide concrete guidelines to prevent and overcome the Taeoom problem that can be applied in practice.