• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.19-32
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• 2021

In this study, evaluation and consideration of domestic/overseas design, construction, and quality control performed by the authors on the deep cement mixing method were performed, and improvements for the development of the DCM method were suggested in the future. As a result of this study, it was found that the cross-sectional area correction for strength is required during the laboratory test of mix proportion, and caution is required because the extrapolation method may lead to different results from the actual one. Applicable design methods should be selected in consideration of both the improvement ratio and the type of improvement during design, and it was confirmed that the allowable compressive strength to which the safety factor was applied refers to the standard value for stability review and not the design parameters. In the case of the stress concentration ratio, rather than applying a conventional value, it was possible to perform economical design by calculating the experimental and theoretical stress concentration ratio reflecting the design conditions. In the case where pre-boring is expected during construction, if the increased water content is not large compared to the original, there were cases where a major problem did not occur even if the result that did not consider the increase in water content was used. In addition, it was confirmed that when the ratio of the top treatment length to the improved length is high, a small amount of design cement contents per unit length can be injected during construction. In the case of quality control, it was evaluated that D/4~2D/4 for single-axis and D/4 point for multi-axis were optimal for coring of grouting mixtures. As an item for quality control, it is judged that the standard that considers the TCR along with the unconfined compressive strength of grouting mixtures is more suitable for the domestic situation.

• Journal of Biomedical Engineering Research
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• v.42 no.6
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• pp.259-267
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• 2021

Recently, the market for personal health care and medical devices based on Bluetooth Low Energy(BLE) has grown rapidly. BLE is being used in various medical data communication devices based on low power consumption and universal compatibility. However, since data errors occurring in the transmission of medical data can lead to medical accidents, it is necessary to analyze the causes of errors and study methods to reduce data error. In this paper, the minimum communication speed to be used in medical devices was set to at least 800 byte/sec based on the wireless electrocardiography regulations of the Ministry of Food and Drug Safety. And the data loss rate was tested when data was transmitted at a speed higher than 800 byte/sec. The factors that cause communication data error were classified, and the relationship between each factor and the data error rate was analyzed through experiments. When there were two or more activated peripherals connected to the central, data error occurred due to channel hopping and bottleneck, and the data error rate increased in proportion to the communication distance and the number of activated peripherals. Through this experiment, when the BLE is used in a medical device that intermittently transmits biosignal data, the risk of a medical accident is predicted to be low if the number of peripherals is 3 or less. But, it was determined that BLE would not be suitable for the development of a biosignal measuring device that must be continuously transmitted in real time, such as an electrocardiogram.

• Journal of The Korean Association of Information Education
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• v.26 no.3
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• pp.209-218
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• 2022

The government of South Korea discusses ways to expand computer science education to solve the digital divide. In-service elementary school teachers are also aware of the need for computer science education, with 77.3% of those who responded positively to the expansion of computer science education. The participating elementary school in this study has conducted computer science education for more than an hour per a week since the 1980s. As a result of a survey, the proportion of students taking private education was 16.2%. It shows 50.3% lower than 66.5% of other surveys conducted in 2021, which means the effectiveness in reducing private education when continuous computer science education is being conducted in the school system. In the case study analysis, teachers pointed out that the instructional content varies by instructors due to the absence of the national curriculum. The parents recognized the importance of computer science education but did not know the learning content and mentioned the necessity of the national computer science education curriculum. It means that computer science education should provide a universal educational opportunity as an independent subject in elementary schools for nurturing future talents.

• Journal of Korea Water Resources Association
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• v.55 no.6
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• pp.461-469
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• 2022

It is very important to ensure the reliability of dam inflow data, which is critical in planning and managing the supply and demand of water resources in a basin. However, the simple water balance model sometimes results in negative inflows and does not consider the actual inflow characteristics. In this study, to address these issues, the existing water balance formula was modified by considering evaporation which is available for calculation among other outflows. The modified water balance formula was applied to the Soyang Dam. The results showed that the rate of negative inflows decreased in the re-evaluated dam inflow data and it was possible to secure consistency for the total inflow volume. In addition, investigating the water availability in the Soyang Dam watershed based on the water balance concept considering evaporation, it was found that direct water use in the human aspect was about 60%, and the indirect water use in the natural aspect was about 40%. In drought years, it was also confirmed that the proportion of indirect use of water resources increased.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.5
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• pp.449-456
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• 2022

This study proposes a deep learning algorithm to predict crop yield using GIS (Geographic Information System) to extract soil properties from Soilgrids and soil suitability class maps. The proposed model modified the structure of a published CNN-RNN (Convolutional Neural Network-Recurrent Neural Network) based crop yield prediction model suitable for the domestic crop environment. The existing model has two characteristics. The first is that it replaces the original yield with the average yield of the year, and the second is that it trains the data of the predicted year. The new model uses the original field value to ensure accuracy, and the network structure has been improved so that it can train only with data prior to the year to be predicted. The proposed model predicted the yield per unit area of autumn cabbage for kimchi by region based on weather, soil, soil suitability classes, and yield data from 1980 to 2020. As a result of computing and predicting data for each of the four years from 2018 to 2021, the error amount for the test data set was about 10%, enabling accurate yield prediction, especially in regions with a large proportion of total yield. In addition, both the proposed model and the existing model show that the error gradually decreases as the number of years of training data increases, resulting in improved general-purpose performance as the number of training data increases.

• Land and Housing Review
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• v.14 no.1
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• pp.83-97
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• 2023

The study aims to provide an academic basis for the preservation and restoration of abandoned paddy wetland and the enhancement of its carbon accumulation function. First, the temporal change of the wetlands was analysed, and a typological classification system for wetlands was attempted with the goal of carbon reduction. The types of wetland were classified based on three variables: hydrological environment, vegetation, and carbon accumulation, with a special attention on the function of carbon accumulation. The types of abandoned paddy wetlands were classified into 12 categories based on hydrologic variables- either high or low levels of water inflow potential-, vegetation variables with either dominance of aquatic plants or terrestrial plants, and three carbon accumulation variables including organic matter production, soil organic carbon accumulation, and decomposition. It was found that the development period of abandoned paddy analyzed with aerial photographs provided by the National Geographic Information Institute happened between 2010 and 2015. In the case of the wetland in Daejeon 1 (DJMN01) farming stopped by 1990 and it appeared to be a similar structure to natural wetlands after 2010 . Over the past 40 years the abandoned paddy wetland changed to a high proportion of forests and agricultural lands. As time went by, such forests and agricultural lands tended to decrease rapidly and the lands were covered by artificial grass and other types of forests.

• 한국노년학
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• v.40 no.3
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• pp.485-509
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• 2020

This study reviews empirical studies that investigated the impact of marketization of long-term care services on quality of care in Korea, England, Sweden, United States, and Japan. The trend and characteristics of marketization and regulatory system in those countries were compared. Since 2008 when long-term care insurance was introduced in Korea, we selected and reviewed empirical studies which were listed in the National Research Foundation, PubMed and Web of Science and examined the relationship between marketization and quality of care. Seven Korean, three English, two Swedish, seven American studies and one Japan study were identified and there was little evidence supporting that marketization would lead to better quality of care. Specifically, competition had no consistent relationship with quality of care while there was little evidence supporting that for-profit nursing homes tended to exhibit greater quality of care compared to non-for-profit nursing homes. The chains of for-profit nursing homes were revealed to have greater deficiencies. The findings of this review imply that improvement of quality of care may not be achieved by making for-profit nursing homes have chains. Reconstruction of nursing home markets should be needed, and the number and the proportion of public and non-for-profit nursing homes should be increased.

• Journal of Intelligence and Information Systems
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• v.28 no.4
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• pp.309-328
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• 2022

This study empirically analyzed a Korean pre-trained language models (PLMs) designed for natural language generation. The performance of two PLMs - BART and GPT - at the task of abstractive text summarization was compared. To investigate how performance depends on the characteristics of the inference data, ten different document types, containing six types of informational content and creation content, were considered. It was found that BART (which can both generate and understand natural language) performed better than GPT (which can only generate). Upon more detailed examination of the effect of inference data characteristics, the performance of GPT was found to be proportional to the length of the input text. However, even for the longest documents (with optimal GPT performance), BART still out-performed GPT, suggesting that the greatest influence on downstream performance is not the size of the training data or PLMs parameters but the structural suitability of the PLMs for the applied downstream task. The performance of different PLMs was also compared through analyzing parts of speech (POS) shares. BART's performance was inversely related to the proportion of prefixes, adjectives, adverbs and verbs but positively related to that of nouns. This result emphasizes the importance of taking the inference data's characteristics into account when fine-tuning a PLMs for its intended downstream task.

• Journal of Trauma and Injury
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• v.35 no.2
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• pp.108-114
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• 2022

Purpose: The coronavirus disease 2019 (COVID-19) pandemic has had major effects worldwide, including sudden and forceful setbacks to the healthcare system. The COVID-19 pandemic has also led to changes in the plastic and reconstructive management of emergency cases, including those due to road traffic accidents. This study analyzed changes in patterns of plastic surgery emergencies and modifications in consultation policies to minimize the exposure of healthcare workers. Methods: Data on plastic surgery emergency calls received from the trauma and emergency department were collected for a period of 2 months before and during lockdown. The data were then analyzed with respect to the cause, mechanism, and site of the injury, as well as other variables. Results: During lockdown, there was a 40.4% overall decrease in the plastic surgery emergency case volume (168 vs. 100). The average daily number of consultations before lockdown was 2.8 as compared to 1.6 during lockdown. Road traffic accidents remained the most common mechanism of injury in both groups (45.8% vs. 39.0%) but decreased in number during the lockdown (77 vs. 39). Household accidents, including burns, were the second most common cause of injury in both phases (7.7% vs. 20.0%), but their proportion increased significantly from 7.7.% to 20.0% in the lockdown phase (P=0.003). The percentage of minor procedures done in the emergency department increased from 53.5% to 72.0% during lockdown (P=0.002). Procedures in the operating room decreased by 73.1% during lockdown (67 vs. 18, P=0.001). Conclusions: The COVID-19 pandemic and lockdown orders in India greatly influenced trends in traumatic emergencies as observed by the plastic surgery team at our tertiary care center. Amidst all the chaos and limitations of the pandemic period, providing safe and prompt care to the patients presenting to the emergency room was our foremost priority.

• Journal of Industrial Convergence
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• v.20 no.5
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• pp.1-9
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• 2022

Today, apartment houses account for a very high proportion of the types of residence. This study analyzed the difference between the bidding construction cost using the long-term repair allowance and using the general repair cost, and analyzed the difference of factors affecting the amount of use of these two items. For this purpose, related data on apartment housing complexes located in seven representative districts of Busan from 2017 to 2021 were collected and analyzed from the apartment housing management information system. As a result of statistical analysis, the type of bidding variable had the greatest negative(-) effect on the bidding construction cost, and the next factor that affected was different between the amount of long-term repair allowance used and general repair cost used. In addition, there was a difference in statistical significance in the type of bidding by construction year for the number of bidding works between the case of using the long-term repair allowance and the case of using the general repair cost. The results of this analysis will help to find ways to reduce bidding construction costs. However, it is expected to find additional meaning by including more detailed variables such as technical ability.