• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.21-31
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• 2018

Bucket foundations are widely used in offshore areas due to their various benefits such as easy and fast installations. A bucket is installed using self-weight and the hydraulic pressure difference across the lid generated by pumping out water from inside the bucket. When buckets are installed in high permeable soil such as sands, upward seepage flow occurs around the bucket tip and interior, leading to a decrease in the effective stress in the soil inside the buckets. This process reduces the penetration resistance of buckets. However, the soil inside and outside the bucket can be disturbed due to the upward seepage flow and this can change the soil properties around the bucket. Moreover, upward seepage flow can create significant soil plug heave, thereby hindering the penetration of the bucket to the target depth. Despite of these problems, soil disturbance and soil plug heave created by suction installation are not well understood. This study aims to investigate the behavior of soil during suction installation. To comprehend the phenomena of soil plug heave during installation, a series of small-scale model tests were conducted with different testing conditions. From a series of tests, the effects of tip thickness of bucket, penetration rate, and self-weight were identified. Finally, soil properties inside the bucket after installation were approximated from the measured soil plug heave.

• Journal of Korea Entertainment Industry Association
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• v.14 no.2
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• pp.27-40
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• 2020

Recently, popular entertainers have contributed significantly to the achievement of TV program and exportation, which make them attract more attention. Therefore, this study investigates the relationship perception of broadcasting entertainers in inductive interview study. Thoughts of entertainers can affect theirs' behavior and attitude as well as value and thought, which makes it necessary on celebrity studies to examine entertainers' ideas. This study divides into drama and variety show for genres and cast portions are classified into three categories; leading, supporting, and minor role. We conducted an interview study on 48 entertainers in drama and variety entertainment programs and have explored data by using Nvivo 11 program. Entertainers' perception on their relationship in program can be sub-categorized into ideas on PDs, script writers, and colleague entertainers. Perception on PD revealed significant difference on consciousness on PDs' and script writers' authority, treatment, and communication. In addition, perception on colleague entertainers revealed significant result on colleague membership, relationship between seniors and newcomers, competition, and communication with colleagues. Because this study covered all relationship perceptions, and it is possible to come up with new practical implications, it is difficult to suggest diverse guidance for the harmonious awareness of entertainers. Therefore, future studies should be analyzed to address these limitations and provide more implications.

• 한국노년학
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• v.40 no.2
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• pp.291-309
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• 2020

In this study, the behavioral model of Andersen and Newman(1973) was applied to identify the factors influencing the use of senior centers by the elderly in the community, and the mediating effect of user satisfaction was improved to improve the satisfaction of seniors using the Senior Center and operate the Senior Center. This study attempted to suggest policy and practical alternatives for activation. The subjects were 578 elderly people using 2,283 senior centers in Busan. As a result, the factors influencing the total usage period of the Senior Center were analyzed by age and type of potential factors among the leading factors, and the factors affecting the total number of days of senior center usage during the week were gender, age, and education level among the preceding factors. Appeared. Factors affecting user satisfaction as a parameter were analyzed as subjective health status among gender, age, and desire factors among preceding factors. As a result of verification of mediating effect of user satisfaction, there was a partial mediating effect between age and total use of Senior Center, full mediating effect between gender and days of Senior Center use, and partial mediating effect between age and Senior Center use days. Analyzed. According to the purpose and main findings of the study, the policy and practical suggestions for activating the satisfaction and use of Senior Center are as follows. First, program development and support according to the characteristics of senior center users are required. Second, there is a need to characterize per-path according to senior center type and regional environment. Third, there is a need to improve and raise the support standards for senior center operating expenses.

• Biomolecules & Therapeutics
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• v.31 no.2
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• pp.227-239
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• 2023

Major depressive disorder is a leading cause of disability in more than 280 million people worldwide. Monoamine-based antidepressants are currently used to treat depression, but delays in treatment effects and lack of responses are major reasons for the need to develop faster and more efficient antidepressants. Studies show that ketamine (KET), a PCP analog, produces antidepressant effects within a few hours of administration that lasts up to a week. However, the use of KET has raised concerns about side effects, as well as the risk of abuse. 4 -F-PCP analog is a novel PCP analog that is also an NMDA receptor antagonist, structurally similar to KET, and might potentially elicit similar antidepressant effects, however, there has been no study on this subject yet. Herein, we investigate whether 4-F-PCP displays antidepressant effects and explored their potential therapeutic mechanisms. 4-F-PCP at 3 and 10 mg/kg doses showed antidepressant-like effects and repeated treatments maintained its effects. Furthermore, treatment with 4-F-PCP rescued the decreased expression of proteins most likely involved in depression and synaptic plasticity. Changes in the excitatory amino acid transporters (EAAT2, EAAT3, EAAT4) were also seen following drug treatment. Lastly, we assessed the possible side effects of 4-F-PCP after long-term treatment (up to 21 days). Results show that 4-F-PCP at 3 mg/kg dose did not alter the cognitive function of mice. Overall, current findings provide significant implications for future research not only with PCP analogs but also on the next generation of different types of antidepressants.

• Tunnel and Underground Space
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• v.33 no.4
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• pp.228-243
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• 2023

Bentonite is widely recognized and utilized as a buffer material in high-level radioactive waste repositories, mainly due to its favorable characteristics such as swelling capability and low permeability. Bentonite buffers play an important role in ensuring the safe disposal of radioactive waste by providing a low permeability barrier and effectively preventing the migration of radionuclides into the surrounding rock. However, the long-term performance of bentonite buffers still remains a subject of ongoing research, and one of the main concerns is the erosion of the buffer induced by swelling and groundwater flow. The erosion of the bentonite buffer can significantly impact repository safety by compromising the integrity of buffer and leading to the formation of colloids that may facilitate the transport of radionuclides through groundwater, consequently elevating the risk of radionuclide migration. Therefore, it is very important to numerically quantify the erosion of bentonite buffer to evaluate the long-term performance of bentonite buffer, which is crucial for the safety assessment of high-level radioactive waste disposal. In this technical note, Two-region model is introduced, a proposed model to simulate the erosion behavior of bentonite based on a dynamic bentonite diffusion model, and quantitative evaluation is conducted for the bentonite buffer erosion with this model.

• Journal of Science Education
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• v.47 no.2
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• pp.139-153
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• 2023

This study aimed to investigate the effect of environmental education programs using action learning on elementary school students' environmental literacy and self-efficacy. To this end, an environmental education program using action learning was applied to 22 sixth graders of 'A' Elementary School in Busan. The results of this study were as follows. First, environmental education programs using action learning were effective in improving the environmental literacy of elementary school students. After implementing the environmental education program using action learning, students' environmental values, cognitive, and procedural ability changed positively. Environmental issues awareness and ecological knowledge improved, and there was a significant increase in environmental behavior and environmental function. Second, environmental education programs using action learning were effective in enhancing the self-efficacy of elementary school students. After implementing environmental education programs using action learning, students' confidence in problem solving and their ability to judge their behaviors improved. Third, elementary school students showed active participation and interest when conducting environmental education programs using action learning. Students have become open to protecting the environment when they find problems, devise solutions, and practice them. After reflection, it was confirmed that students' immersion and satisfaction in class were high as a solution was reached, leading to efforts to sell items they did not use and donate profits to environmental protection organizations.

• Journal of Industrial Convergence
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• v.21 no.5
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• pp.77-85
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• 2023

Suicide is the leading cause of death among Korean adolescents. There is a growing interest in the role of loneliness as a risk factor for suicide ideation and depressive symptoms. However, little is known in the Korean context. This study analyzed a total of 109,796 respondents from the Korea Youth Health Behavior Survey in 2020 and 2021. Multiple logistic regression models were implemented to test the association between loneliness and either of suicidal ideation and depressive mood. Covariates included demographic characteristics, school enrolled, household income, living arrangement, self-rated health, and the number of times treated for violence. Adjusted odd ratio (OR) and 95% confidence intervals (CI) were computed. 12.0% of adolescents reported to have felt lonely frequently and 3.0% always. 11.8% and 26.0% had suicidal ideation and depressive mood, respectively. The prevalence of suicidal ideation was higher in the always-lonely adolescents (52.6%) than in the frequently-lonely adolescents (35.1%). The always-lonely adolescents were nearly 30 times more likely to have suicidal ideation (OR=30.7; 95% CI, 27.1 - 34.8) and to feel depressed (OR=32.5; 95% CI, 29.2 - 36.4) than adolescents who felt never lonely. In conclusion, Loneliness was a major risk factor for suicidal ideation and depressive mood among Korean adolescents. Monitoring and addressing the condition of loneliness may help reduce suicidal ideation and depressive mood.

• Journal of Technology Innovation
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• v.30 no.1
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• pp.21-56
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• 2022

Since Michael Porter (1991) has proposed that environmental regulation can help a firm increase its competitiveness by encouraging it to engage in more innovative activities to meet the environmental regulation, a number of researchers have empirically investigated the "Porter Hypothesis." However, the empirical results still remain mixed. Combining the perspectives of the behavioral theory of the firm and firm heterogeneity, we argue that the levels of regulation stringency and time-pressure would differentially influence a firm's innovative behavior depending on the firm's aspiration level, performance feedback and technological capabilities. Using the U.S. Corporate Average Fuel Efficiency (CAFE) regulation context, we empirically demonstrate that lagging firms that do not meet the new regulation standard announced by the government tend to search for more distant knowledge and that the impact of the patents they file for decreases as the regulation becomes more stringent. In addition, we also find that as time-pressure increases, lagging firms stand to apply for more patents than do leading firms whereas the overall impact of the patents decreases. These results help us advance our understanding of the nuanced causal relationship between regulation and innovation and provide practical implications for policymakers.

• Tuberculosis and Respiratory Diseases
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• v.86 no.2
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• pp.82-93
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• 2023

Tuberculosis (TB) is a significant public health concern. Globally, TB is among the top 10 and the leading cause of death due to a single infectious agent. Providing standard anti-TB therapy for at least 6 months is recommended as one of the crucial strategies to control the TB epidemic. However, the long duration of TB treatment raised the issue of non-adherence. Non-adherence to TB therapy could negatively affect clinical and public health outcomes. Thus, directly observed therapy (DOT) has been introduced as a standard strategy to improve anti-TB medication adherence. Nonetheless, the DOT approach has been criticized due to inconvenience, stigma, reduced economic productivity, and reduced quality of life, which ultimately could complicate adherence issues. Apart from that, its effectiveness in improving anti-TB adherence is debatable. Therefore, digital technology could be an essential tool to enhance the implementation of DOT. Incorporating the health belief model (HBM) into digital technology can further increase its effectiveness in changing behavior and improving medication adherence. This article aimed to review the latest evidence regarding TB medication non-adherence, its associated factors, DOT's efficacy and its alternatives, and the use of digital technology and HBM in improving medication adherence. This paper used the narrative review methodology to analyze related articles to address the study objectives. Conventional DOT has several disadvantages in TB management. Integrating HBM in digital technology development is potentially effective in improving medication adherence. Digital technology provides an opportunity to improve medication adherence to overcome various issues related to DOT implementation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.831-838
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• 2006

An experimental/analytic study has been conducted to understand the adverse effects of low vehicle speed, high axle load and high tire pressure on the performance of asphalt pavements. Of 33 asphalt sections at KHC test road, two sections having different base layer thickness (180 mm versus 280 mm) are adopted for rollover tests. During the test, a standard three-axle dump truck maintains a steady state condition as moving along the wheel path of a passing lane, and lateral offsets and real travel speed are measured with a laser-based wandering system. Test results suggest that vehicle speed affects both longitudinal and transverse strains at the bottom of asphalt layer (290 mm and 390 mm below the surface), and even slightly influences the measured vertical stresses at the top of subbase and subgrade due to the dynamic effect of rolling vehicle. Since the anisotropic nature of asphalt-aggregate mixtures, the difference between longitudinal and transverse strains appears prominent throughout the measurements. As the thickness of asphalt pavement increases, the measured lateral strains become larger than its corresponding longitudinal strains. Over the limited testing conditions, it is concluded that higher axle weight and higher tire pressures induce more strains and vertical stresses, leading to a premature deterioration of pavements. Finally, a layered elastic analysis overestimates the maximum strains measured under the 1st axle load, while underestimating the maximum vertical stress in both pavement sections.