• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2C
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• pp.109-117
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• 2010

Gas hydrate dissociation can generate large amounts of gas and water in gas hydrate bearing sediments, which may eventually escape from a soil skeleton and form voids within the sediments. The loss of fine particles between coarse particles or collapse of cementation due to water flow during heavy or continuous rainfall may form large voids within soil structure. In this study, the effect of void formation resulting from gas hydrate dissociation or loss of some particles within soil structure on the strength of soil is examined. Glass beads with uniform gradation were used to simulate a gas hydrate bearing or washable soil structure. Glass beads were mixed with 2% cement ratio and 7% water content and then compacted into a cylindrical sample with five equal layers. Empty capsules for medicine are used to mimic large voids, which are bigger than soil particle, and embedded into the middle of five equal layers. The number, direction, and length of capsules embedded into each layer vary. After two days curing, a series of unconfined compression tests is performed on the capsule-embedded cemented glass beads. Unconfined compressive strength of cemented glass beads with capsules depends on the volume, direction and length of capsules. The volume and cross section formed by voids are most important factors in strength. An unconfined compressive strength of a specimen with large voids decreases up to 35% of a specimen without void. The results of this study can be used to predict the strength degradation of gas hydrate bearing sediments in the long term after dissociation and loss of fine particles within soil structure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.575-589
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• 2008

In the present work, we investigate the hydrodynamic behavior of a turbulent bore, such as tsunami bore and tidal bore, generated by the removal of a gate with water impounded on one side. The bore generation system is similar to that used in a general dam-break problem. In order to the numerical simulation of the formation and propagation of a bore, we consider the incompressible flows of two immiscible fluids, liquid and gas, governed by the Navier-Stokes equations. The interface tracking between two fluids is achieved by the volume-of-fluid (VOF) technique and the M-type cubic interpolated propagation (MCIP) scheme is used to solve the Navier-Stokes equations. The MCIP method is a low diffusive and stable scheme and is generally extended the original one-dimensional CIP to higher dimensions, using a fractional step technique. Further, large eddy simulation (LES) closure scheme, a cost-effective approach to turbulence simulation, is used to predict the evolution of quantities associated with turbulence. In order to verify the applicability of the developed numerical model to the bore simulation, laboratory experiments are performed in a wave tank. Comparisons are made between the numerical results by the present model and the experimental data and good agreement is achieved.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.1-8
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• 2023

This study was a descriptive survey study to confirm the correlation between self-differentiation, Nursing Professionalism, and care efficacy in nursing college students, and to confirm the mediating effect of Nursing Professionalism in the relationship between self-differentiation and care efficacy. The data collection period is from October 30 to November 30, 2022. Data analysis was performed using t-test, Pearson's correlation, and regression methods. Studies have shown that the general characteristics that show significant differences in care efficacy were grade level and major satisfaction. The three variables were statically correlated. In the relationship between self-differentiation and care efficacy, Nursing Professionalism appeared to be a partial mediator (Z=2.196, p<0.05). The partial mediated effect explanatory power was 40%. This study was significant in that it examines the partial mediating effect of Nursing Professionalism in the relationship between self-differentiation and care efficacy for nursing college students, and has prepared the basic data for improving the care efficacy of nursing college students in the future. In the follow-up study, it would be created a program to improve the efficacy of care based on the results of this study and propose an analysis study of its effectiveness. It also proposes a study to expand the number of subjects to identify factors that can affect the efficacy of care.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1B
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• pp.89-100
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• 2010

The performance evaluation of a conventional Wave Resonator at the entrance of harbors against solitary wave has been performed using 3D numerical wave flume. A wave resonator has been designed for the attenuation of the transmitted wave energy by trapping the short periodic incident waves only. In this study, however, the controlled performance of the wave resonator by its various widths has been numerically investigated for solitary waves. Source distribution method based on the Green function and the 3D one-field Model for immiscible TWO-Phase flows (TWOPM-3D) using 3D numerical wave flume were used for the short-periodic waves and the solitary waves, respectively, and these models were verified through the comparisons with the previous experimental and numerical results by other researchers. It was confirmed that the wave resonator is effective enough to control the solitary waves as well as the periodic waves when it compares with the case of no resonance system. Further, it was found that there is the optimal width of a wave resonator to attenuate the target solitary waves.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2B
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• pp.111-120
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• 2009

A local scour around a bridge pier is known as one of important factors of bridge collapse. Two approaches are usually used in estimating a scour depth in practice. One is to use empirical formulas, and the other is to use computational methods. But the use of empirical formulas is limited to predict a scour depth under similar conditions to which the formulas were derived. Computational methods are currently too expensive to be applied to practical engineering problems. This study presented the application of artificial neural networks (ANN) to the prediction of a scour depth around a bridge pier at an equilibrium state. This study also investigated various ANN algorithms for estimating a scour depth, such as Backpropagation Network, Radial Basis Function Network, and Generalized Regression Network. Preliminary study showed that ANN models resulted in very wide range of errors in predicting a scour depth. To solve this problem this study incorporated cluster analysis into ANN. The incorporation of cluster analysis provided better estimations of scour depth up to 42% compared with other approaches.

• 한국노년학
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• v.29 no.4
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• pp.1397-1411
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• 2009

This study was aimed to examine the effects of intermittent walking on health related fitness and metabolic syndrome risk factors in elderly women. Forty five elderly women were randomly assigned to three groups: three 10-min walks per day, one 30-min walk per day or no exercise, respectively. Both walking groups exercised three days a week at moderate intensity for 12 weeks. Two-way repeated measures ANOVA was used to test the hypothesis with a significant level of α = .05. The results indicated that body composition(body weight, body mass index, percent body fat), muscle endurance, flexibility and cardiorespiratory fitness significantly increased after 12 weeks for both walking groups. However, it was found that muscle strength significantly increased only in a continuous walking group. Metabolic syndrome risk factors comprised of waist circumference, systolic blood pressure, triglyceride, high-density lipoprotein, and fasting glucose were significantly improved in both walking groups. In addition, there was a difference in these metabolic syndrome risk factors between pre and post exercise. The results of this study support the hypothesis that intermittent walking has a significant impact on health related physical fitness and metabolic syndrome rick factors in elderly women as continuous walking does.

• Journal of Practical Engineering Education
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• v.15 no.1
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• pp.81-88
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• 2023

This study is a descriptive research study to confirmed the effects of academic self-efficacy and clinical practice satisfaction on nursing professionalism of adult learner nursing students. Data were collected from October 1, 2022 to January 31, 2023, targeting 120 adult learners and nursing students attending 5 universities located in C province. Descriptive statistics, correlation analysis, and multiple regression analysis were performed using the SPSS 26.0 program. Results of this study Satisfaction with clinical practice and academic self-efficacy (r=.773, p<.01), Satisfaction with clinical practice and nursing professionalism (r=7.87, p<.01), Academic self-efficacy and nursing professionalism (r=8.34, p<.01), there was a positive correlation with each other. As a result of regression analysis, college life satisfaction, practical peer relationship, major satisfaction, clinical practice satisfaction, and academic self-efficacy were confirmed as factors influencing nursing professionalism (F=57.86, p<.001). The explanatory power was 75.5%. In order to improve the nursing professionalism of adult learner nursing students, an institutional educational strategy will be needed to develop interventions that can increase academic self-efficacy and clinical practice satisfaction.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1143-1149
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• 2023

The purpose of this study was to the effects of case-based learning (CBL) on problem solving ability and academic self-efficacy in nursing students and was a quasi-experimental study with a one-group pretest-posttest design. The subjects of this study were 121 grade 4 students, and the data collection period was from Aprill 24 to June 12, 2023. The research procedure was scenario development, preliminary investigation, application of case-based learning classes, and follow-up investigation, and the CBL was conducted for 2 weeks, 50 minutes per week. The general characteristics of the subjects were obtained by frequency, percentage, mean, and standard deviation and the effects of CBL on problem solving ability and academic self-efficacy was tested using a paired t-test. The results of this study showed that nursing students' problem solving ability (t=-5.70, p<.001) and academic self-efficacy (t=-3.25, p<.002) improved after applying CBL compared to before applying it. We suggest the use of case-based learning as a strategy to improve problem-solving skills and academic self-efficacy in nursing education. In the future, follow-up research is needed to verify the effectiveness by developing and applying step-by-step clinical cases at an appropriate level according to the learning content of nursing major subjects by grade.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.897-907
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• 2023

The purpose of this study is to find out the development direction of adult learners' blended learning class as a study on the class satisfaction of adult college students according to the blended learning class participation type. To this end, a survey was conducted targeting adult learners at two schools that are carrying out the LiFE project (lifelong education system support project). The analyzed research results are as follows. First, in the case of adult learners, the proportion of participating in liberal arts + major classes as a blended learning subject was 77.8%, and home was the highest with 69.8% as a place to participate in online classes. Second, satisfaction with the blended learning teacher/instructor teaching method was generally satisfied with 95.2% of average or higher. Third, 96.8% of the students answered 'yes' or higher regarding the level of satisfaction with the blended learning method. The above research results show that blended learning is one of the important teaching and learning methods in providing adult-tailored education to adult learners who combine work and study. It can be seen that the blended learning teaching method is an effective teaching method that enables interactive communication between the instructor and the learner rather than the one-way teaching-oriented content delivery class of the traditional classroom.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.5
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• pp.105-115
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• 2022

This study aims to investigate the Effect of Money Rush on Entrepreneurial Opportunity Recognition for college students in Busan and Gyeongnam area. We also examine whether Entrepreneurship has a mediating effect between Money Rush and Entrepreneurial Opportunity Recognition. Since the outbreak of COVID-19, digital transformation of the industry have greatly changed the world of work, and job insecurity is becoming more prevalent. As income inequality expands due to the disparity in asset income, the Money Rush phenomenon, which prefers to increase asset income through investment rather than earned income, is becoming common. Money Rush secures an income pipeline and is divided into side hustles and investments that actively utilize Leverage to maximize profits. The findings of this study confirm that Money Rush has a positive effect on Entrepreneurial Opportunity Recognition and a partially positive effect on Entrepreneurship. Entrepreneurship has a partial mediating effect between Money Rush and Entrepreneurial Opportunity Recognition. The study analysis is expected to contribute to strengthening college students' competencies in Entrepreneurial Opportunity Recognition and presenting the policy and practical directions necessary to promote Start-up.