• Journal of the Korean Geotechnical Society
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• v.35 no.4
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• pp.15-26
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• 2019

The stability of the gravity quay wall against earthquakes is evaluated on the basis of the allowable displacement of the wall. To estimate the displacement caused by external forces, empirical equations based on the Newmark sliding block method or numerical analysis are widely used. In numerical analysis, it is possible to analyze precisely a complicated site and structure, but difficult to set the appropriate parameters and environments; there are limitations in obtaining reliable results, depending on one's level of expertise. The Newmark method, with only seismic motions, is widely used because it is simpler than numerical simulations when estimating permanent displacement. However, the empirical equations do not have any parameters for the response characteristics and sliding block of the structure, and sliding blocks being assumed as rigid bodies does not consider the nonlinear behavior of the soil and interaction with the structure. Therefore, in order to evaluate the seismic stability of the gravity quay wall, a newly-developed empirical equation is needed to overcome the above-mentioned limitations. In this study, numerical simulations are performed to analyze the response characteristics of the backfill of the structure, and to propose an optimal method of calculating the active area. For this purpose, finite element analyses were performed to analyze the response characteristics, and stress-strain relationships for various seismic motions. As a result, the response characteristics, sliding block, and failure surface of the backfill vary depending on the input seismic motions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.544-552
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• 2019

The purpose of this study was to find concrete measures to improve the subjective health level, happiness and quality of life of the elderly according to economic level and to propose social and policy alternatives accordingly. As a research method, 63,929 elderly people aged 65 or older were surveyed using the Community Health Survey (Indicator Bank) _v09, and the frequency of health use by economic level, subjective health level, euphoria and quality of life Analysis and Chi square analysis and independent t-test. Multi variate logistic regression analysis was performed with subjective health level as a dependent variable and multiple linear regression analysis was performed to determine the factors affecting euphoria and quality of life. The results of the study are as follows. In the case of recipients, medical use was lower than that of non-recipients, lower education level, female age of 75 years or older, and less stress, In case of present or past recipients, the result of non - receipt increased as the subjective health level was worse, and the non - recipient had higher euphoria and quality of life. As a result, there is a need for alternatives to increase opportunities for medical use among the recipients, with particular attention being paid to women and elderly people over 75 years old. It is expected to be used as a basic data to effectively improve the health promotion, happiness and quality of life of the elderly people of low income group.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.527-534
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• 2019

Several types of mathematical analysis methods are used for port waterway risk assessment based on marine traffic volume. In Korea, a marine traffic congestion model that standardizes the size of the vessels passing through the port waterway is applied to evaluate the risk of the waterway. For example, when marine traffic congestion is high, risk situations such as collisions are likely to occur. However, a scientific review is required to determine if there is a correlation between high density of maritime traffic and a high risk of waterway incidents. In this study, IWRAP Mk2(IALA official recommendation evaluation model) and a marine traffic congestion model were used to analyze the correlation between port waterway risk and marine traffic congestion in the same area. As a result, the linear function of R2 was calculated as 0.943 and it was determined to be significant. The Pearson correlation coefficient was calculated as 0.971, indicating a strong positive correlation. It was confirmed that the port waterway risk and the marine traffic congestion have a strong correlation due to the influence of the common input variables of each model. It is expected that these results will be used in the development of advanced models for the prediction of port waterway risk assessment.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.1008-1017
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• 2019

The purpose of this study was to investigate the effect of the image of nurses and major satisfaction on the nursing professionalism among nursing students in university and to presents basic data for making positive nursing professionalism. A survey was held to the university students in Seoul and Chungcheong cities from May 30 to June 4, 2019. 184 copies were in the final analysis for data analysis, t-test, ANOVA, Pearson's Correlation Coefficient and Multiple regression was used. As a result, the factors of affecting on the nursing professionalism were followed by character, motivation for nursing, future prospects of nursing, image of nurses and major satisfaction. The multiple regression explanatory power was 63.6percent of the total changes in nursing professionalism. Therefore, this study could be used as a basic data for the development of education programs to create positive image through positive self-image and enhance learning satisfaction in order to increase nursing students' professionalism.

• Journal of Digital Convergence
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• v.17 no.1
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• pp.239-247
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• 2019

An accurate prediction of emotion is a very important issue for the sake of patient-centered medical device development and emotion-related psychology fields. Although there have been many studies on emotion prediction, no studies have applied the heart rate variability and neuro-fuzzy approach to emotion prediction. We propose ANFEP(Adaptive Neuro Fuzzy System for Emotion Prediction) HRV. The ANFEP bases its core functions on an ANFIS(Adaptive Neuro-Fuzzy Inference System) which integrates neural networks with fuzzy systems as a vehicle for training predictive models. To prove the proposed model, 50 participants were invited to join the experiment and Heart rate variability was obtained and used to input the ANFEP model. The ANFEP model with STDRR and RMSSD as inputs and two membership functions per input variable showed the best results. The result out of applying the ANFEP to the HRV metrics proved to be significantly robust when compared with benchmarking methods like linear regression, support vector regression, neural network, and random forest. The results show that reliable prediction of emotion is possible with less input and it is necessary to develop a more accurate and reliable emotion recognition system.

• Journal of agricultural medicine and community health
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• v.45 no.4
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• pp.183-193
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• 2020

Objectives: As an ecological study, this study was performed to identify the community-level variation of health related quality-of-life (HRQOL), and to explore the factors that explain the variation, using 2017 Korean Community Health Survey (KCHS) data. Methods: Community health indicators of KCHS, which are correlated with the EQ-5D index of Si-gun-gu districts, were selected as independent variables. Multiple linear regression model was used to derive factors that explain regional variations in the EQ-5D index. Results: The EQ-5D index variation in 229 districts nationwide was 1.1 times for extremal quotient (EQ) and 1.0 for coefficient of variance (CV). The Si-gun-gu districts with the EQ-5D index in the lower 25% were more distributed in the province (27.7%) than in the metropolitan area (20.3%). As a result of multiple linear regression analysis, the depressed mood experience rate, perceived stress rate, suicide ideation rate, and physician diagnosed arthritis rate were derived as major factors of the variation. Conclusions: In order to reduce the gap in HRQOL between the districts, the priority of local health policies should be placed on the above factors including psychosocial factors.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.29 no.3
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• pp.147-153
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• 2011

What kinds of environmental adaptation did people during the Chosun era take when climate change due to drought was perceived and natural disasters occurred? Research hypotheses is 'More environmental improvement projects were conducted when climate disasters were experienced than rituals for rain calling. In this study, frequency samples for Rituals for Rain (RR, 祈雨祭) defined as abnormal climate of drought, Climate Disaster(CD) and Environmental Improvement Projects(EIP) were extracted from "Chosunwangjoshillok(朝鮮王朝實錄)". The analysis among RR, CD, and EIP were studied for a regression model. Research hypothesis was statistically tested. RR took placed the order of Sejong(世宗), Sukjong(肅宗) and Youngjo(英祖), while climate disasters were extracted under the Jungjong(中宗), Sungjong(成宗) and Taijong(太宗). EIP were most active under Youngjo(英祖), Sungjong(成宗) and Taijong(太宗). During the former part of the Chosun dynasty, abnormal climate was more seriously considered than climate disasters, while the opposite pattern was shown during the latter part. In a regression analysis between EIP and CD, the equation of EIP = 0.632CD was determined. As a test result, the study hypothesis the entire Chosun dynasty was dismissed. However, it is possible to statistically support that more EIP were conducted in order to adapt to the climate change during the latter part of the dynasty when climate disaster were experienced.

• Journal of the Korea Convergence Society
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• v.12 no.6
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• pp.225-232
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• 2021

The purpose of this study is to identify the psychological characteristics of the elderly and to investigate the variables that affect the life satisfaction of the elderly. To achieve this purpose, psychological characteristics such as self-esteem, alienation, loss, and depression were selected. A survey was conducted on the elderly living in Gwangju Metropolitan City. A total of 218 copies were collected and 203 copies were analyzed, excluding poor responses. To draw the results of the research, quantitative analysis was conducted through questionnaires, and SPSSWIN 21.0 statistical program was used as an analysis tool. The analysis methods were frequency and ratio analysis, technical statistical analysis, bivariate correlation analysis, and linear regression analysis. The results of the analysis are as follows: First, the relationship between the psychological characteristics of the elderly showed significant correlations among the self-esteem, alienation, loss, depression, and life satisfaction of the elderly. Second, for the elderly, alienation and depression had a negative effect on life satisfaction, and self-esteem had a positive effect on life satisfaction. However, loss did not have a significant effect on life satisfaction. In conclusion, it suggests that it is necessary to develop and operate policies and programs to improve self-esteem and reduce alienation and depression in order to improve the quality of life of the elderly.

• Geophysics and Geophysical Exploration
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• v.24 no.2
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• pp.53-66
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• 2021

Velocity model building is an essential procedure in seismic data processing. Conventional techniques, such as traveltime tomography or velocity analysis take longer computational time to predict a single velocity model and the quality of the inversion results is highly dependent on human expertise. Full-waveform inversions also depend on an accurate initial model. Recently, deep neural network techniques are gaining widespread acceptance due to an increase in their integration to solving complex and nonlinear problems. This study investigated cases of seismic velocity model building using deep neural network techniques by classifying items according to the neural networks used in each study. We also included cases of generating training synthetic velocity models. Deep neural networks automatically optimize model parameters by training neural networks from large amounts of data. Thus, less human interaction is involved in the quality of the inversion results compared to that of conventional techniques and the computational cost of predicting a single velocity model after training is negligible. Additionally, unlike full-waveform inversions, the initial velocity model is not required. Several studies have demonstrated that deep neural network techniques achieve outstanding performance not only in computational cost but also in inversion results. Based on the research results, we analyzed and discussed the characteristics of deep neural network techniques for building velocity models.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.77-84
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• 2021

In this study, flexural tests of prestressed high strength spun concrete (PHC) piles reinforced with infilled concrete and longitudinal rebars were conducted, where the longitudinal rebar ratio and the presence of sludge formed on the inner surface of PHC pile were set as key test variables. A total of six PHC pile specimens were manufactured, and their flexural behaviors including failure mode, crack pattern, longitudinal strain distribution in a section and end slip between external PHC pile and infilled concrete were measured and discussed in detail. The test results revealed that the flexural stiffness and strength increased as the longitudinal rebar ratio became larger, and that the sludge formed on the inner surface of PHC pile did not show any detrimental effect on the flexural performance. In addition to the experimental approach, this study presents a nonlinear flexural analysis model considering compatibility conditions and strain and stress distributions of the PHC piles and infilled concrete. The rationality of the nonlinear flexural analysis model was verified by comparing it with test results, and it appeared that the proposed model well evaluated the flexural behavior of PHC piles reinforced with infilled concrete and longitudinal rebars with a good accuracy.