• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.4
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• pp.523-530
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• 2019

Pavement distress and traffic accidents are caused by pot-hole. In addition, direct and indirect damages of road users are increasing, such as loss of life due to personal injury and damage to vehicles. Generally, the asphalt concrete pavements are continuously aging from the production process to the terminal performance period. Aging causes stripping due to cracks and moisture penetration and weakening the pavement structure to induce pot-hole. In this study, adhesion performance and moisture sensitivity were evaluated according to aging degree in order to investigate the effect of aging on asphalt pavement. As a result of the study, the viscosity of the asphalt binder was increased with aging and the bond strength of the aged was increased 2~3 times than that of the unaged. The results of accelerated aging test showed an increases in indirect tensile strength and the increase in the TSR (Tensile Strength Ratio) by 4.2~8.9 %. As a result, it is noted that the anti-stripping and adhesion performances of the aged asphalt concrete are improved compared to the unaged one under the aging conditions of asphalt binder coated on aggregates.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.351-357
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• 2019

This research was performed to propose domestic standard for design and management of flexible hose by analyzing chlorine leak caused by breakage of the hose in Ulsan, 2018. The leak had multiple causes but this paper focuses on analyzing the cause of breakage of flexible hose, the direct cause. According to the analysis, flexible hose that the company of the accident used for chlorine transfer was inappropriate in several aspects including material and wall thickness. And even pressure test had been conducted below operating pressure. Upon investigation on five companies that handle chlorine in Ulsan, four companies were using inappropriate flexible hose for chlorine transfer. Since there is no domestic standard for the design of flexible hose for chlorine transfer at present, it is hard to examine its design adequacy. Design standard of flexible hose used in chlorine transfer that is applicable domestically is proposed based on this research. It will contribute to the reduction in risk of breakage of the hose if the proposed standard could be applied in design and examination of flexible hose.

• Structural Engineering and Mechanics
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• v.70 no.4
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• pp.499-511
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• 2019

In this study, the axial compressive behavior of novel quadruple C-channel built-up cold-formed steel columns with different slenderness ratio was investigated, using the experimental and numerical analysis. The axial compressive capacity and failure modes of the columns were obtained and analyzed. The finite element models considering the geometry, material and contact nonlinearity were developed to simulate and analyze the structural behavior of the columns further. There was a great correlation between the numerical analyses and test results, which indicated that the finite element model was reasonable and accurate. Then influence of, slenderness ratio, flange width-to-thickness ratio and screw spacing on the mechanical behavior of the columns were studied, respectively. The tests and numerical results show that due to small slenderness ratio, the failure modes of the specimens are generally local buckling and distortional buckling. The axial compressive strength and stiffness of the quadruple C-channel built-up cold-formed steel columns decrease with the increase of maximum slenderness ratio. When the screw spacing is ranging from 150mm to 450mm, the axial compressive strength and stiffness of the quadruple C-channel built-up cold-formed steel columns change little. The axial compressive capacity of quadruple C-channel built-up cold-formed steel columns increases with the decrease of flange width-thickness ratio. A modified effective length factor is proposed to quantify the axial compressive capacity of the quadruple C-channel built-up cold-formed steel columns with U-shaped track in the ends.

• Journal of Coastal Disaster Prevention
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• v.4 no.3
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• pp.119-131
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• 2017

Global warming under the influence of climate change and its direct impact on glacial and sea level are known issue. However, there is a lack of research on an indirect impact of climate change such as coastal structure design which is mainly based on a frequency analysis of water level under the stationary assumption, meaning that maximum sea level will not vary significantly over time. In general, stationary assumption does not hold and may not be valid under a changing climate. Therefore, this study aims to develop a novel approach to explore possible distributional changes in annual maximum sea levels (AMSLs) and provide the estimate of design water level for coastal structures using a multiple non-crossing quantile regression based nonstationary frequency analysis within a Bayesian framework. In this study, 20 tide gauge stations, where more than 30 years of hourly records are available, are considered. First, the possible distributional changes in the AMSLs are explored, focusing on the change in the scale and location parameter of the probability distributions. The most of the AMSLs are found to be upward-convergent/divergent pattern in the distribution, and the significance test on distributional changes is then performed. In this study, we confirm that a stationary assumption under the current climate characteristic may lead to underestimation of the design sea level, which results in increase in the failure risk in coastal structures. A detailed discussion on the role of the distribution changes for design water level is provided.

• Journal of Korean Neuropsychiatric Association
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• v.56 no.1
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• pp.28-34
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• 2017

Objectives The purpose of this study was to evaluate psychological effects of an outbreak of Middle East respiratory syndrome (MERS), a newly emerged infectious disease, on doctors. Methods After the MERS outbreak was over, we conducted an online survey of doctors who worked at the hospitals in which exposure to MERS cases had been confirmed or who were directly involved in MERS diagnosis and treatment. The Patient Health Questionnaires-9 (PHQ-9) and the Impact of Event Scale-Revised (IES-R) assessment methods were used to assess the severity of depressive and posttraumatic stress symptoms among the 64 doctors participating in the survey. Results The results of the survey indicate that 26.6% (n=17) of participants exhibited depressive symptoms and 7.8% (n=5) had post-traumatic stress symptoms. The doctors employed at hospitals with MERS cases had higher PHQ-9 and IES-R mean scores than those in doctors were not so employed. In contrast, there was no significant difference in those test scores between doctors who participated directly in MERS diagnosis and treatment and those doctors who did not. Conclusion The survey demonstrated that 28.1% (n=18) of doctors involved in MERS care suffered from depressive or posttraumatic stress symptoms, even though the MERS infection was being controlled. Working at a hospital with MERS cases was the primary determinant of the adverse psychological outcomes among doctors ; however, direct participation in the diagnosis and care of MERS patients was not significantly related to such outcomes.

• Asia-Pacific Journal of Business
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• v.12 no.1
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• pp.41-56
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• 2021

Purpose - This empirical study examined the influence of post-communist countries sociol-political factor of freedom of expression preconditioning, and trust in agency, mediating performance expectancy of social media users representing the citizens' behavioural intention to utilize social media in a post-communist country, the case of Mongolia. Design/methodology/approach - This research collected 403 valid survey data from citizens those who use social media in Mongolia. The study used Partial Least Squire (PLS) analysis with the research conceptual model founded on the UTAUT model. Findings - The study shown that citizens in post-communist, they strongly willing freedom of expression, which driving as a positive precondition factor, and this has an indirect positive influence, and trust in agency mediates to enhance performance expectancy. Social influence, and effort expectancy factors have direct positive influence on the intention to use of social media systems in the public sector domain of Mongolia. Research implications or Originality - This research proposed a new model to test citizens' intention to use social media as a communication tool to engage with public organizations in the pre-adoption stage of post-communist countries. Theoretically, this research builds up to the unique theoretical contribution with social media by examining a new social media-based third-party intercommunication medium, incorporating intent to utilize for citizens with government in post-communist countries. Practically, this article lays out the directions to aid social media usage for government sector with concerning citizens intentions in the post-communist situation.

• Journal of Convergence for Information Technology
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• v.11 no.4
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• pp.153-160
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• 2021

Goal of this study is to introduce newly developed Oral Motor Facilitation Technique(OMFT), to identify effect of oral motor therapy on oral praxis and oral function of Down syndrome child. OMFT is comprehensive oral motor therapy for improving sensory adaptation, oral sensori-motor function, oral motor coordination of oro-facial structure by therapist's direct manual stroking. Subject was 10years old down syndrome boy. Treatment was practiced 8 times, 15minutes per time, from May to July, 2020. Oral praxis, drooling, quality of chewing ability were tested before and after treatments. Every single items of Oral Praxis Test was increased. Severity and frequency of drooling were decreased. Quality of chewing ability is improved. Through this case study, we can find the positive effect of OMFT on oral praxis, drooling, chewing ability of Down syndrome child.

• Journal of Korean Clinical Nursing Research
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• v.27 no.2
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• pp.210-219
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• 2021

Purpose: The study was conducted to investigate the correlation between perception of patient safety risk factors, patient safety competency, and safety nursing activities of nurses in hemodialysis units and identify factors affecting patient safety activities. Methods: The participants were 146 nurses from 16 hemodialysis units located in Gyeongsangnam-do. Data were analyzed using descriptive statistics, independent t-test, one-way ANOVA, Pearson correlation coefficient, and multiple regression analysis using the SPSS, version 24.0. Results: The mean safety nursing activity score was 3.47±0.38. safety nursing activities of the participants were significantly correlated with patient safety competency. The characteristics showing significant differences in safety nursing activities were educational level, hospital type, hospital work experience, number of hemodialysis treatment per day, number of hemodialysis treatment per nurse, educational experience of patient safety, presence of a patient safety incident report registration system, and direct registration of patient safety incident report. The multiple regression analysis revealed that the factors influencing safety nursing activities were patient safety incident report, patient safety competency, and number of daily hemodialysis treatment (<5~7 times/day) per nurse (R²=.34). Conclusion: The results of this study suggest that the safety nursing activities of hemodialysis unit nurses should be intensified. In addition, the registration system of patient safety incident report and nurses' competency on patient safety should be improved, and the number of hemodialysis per nurse should be fewer than 7 times per day.

• Journal of Korean Academy of Nursing
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• v.49 no.4
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• pp.375-385
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• 2019

Purpose: This study aimed to develop and test a structural model for chemotherapy-related cognitive impairment of breast cancer patients based on a literature review and Hess and Insel's chemotherapy-related cognitive change model. Methods: The Participants consisted of 250 patients who were ${\geq}19$ years of age. The assessment tools included the Menopause Rating Scale, Symptom Experience Scale, Hospital Anxiety and Depression Scale, Everyday Cognition, and Functional Assessment of Cancer Therapy-Breast Cancer. Data were analyzed using the SPSS 21.0 and AMOS 21.0 programs. Results: The modified model was a good fit for the data. The model fit indices were ${\chi}^2=423.18$ (p<.001), ${\chi}^2/df=3.38$, CFI=.91, NFI=.91, TLI=.89, SRMR=.05, RMSEA=.09, and AIC=515.18. Chemotherapy-related cognitive impairment was directly influenced by menopausal symptoms (${\beta}=.38$, p=.002), depression and anxiety (${\beta}=.25$, p=.002), and symptom experiences (${\beta}=.19$, p=.012). These predictors explained 47.7% of the variance in chemotherapy-related cognitive impairment. Depression and anxiety mediated the relations among menopausal symptoms, symptom experiences, and with chemotherapy related cognitive impairment. Depression and anxiety (${\beta}=-.51$, p=.001), symptom experiences (${\beta}=-.27$, p=.001), menopausal symptoms (${\beta}=-.22$, p=.008), and chemotherapy-related cognitive impairment (${\beta}=-.15$, p=.024) had direct effects on the quality of life and these variables explained 91.3%. Conclusion: These results suggest that chemotherapy-related toxicity is highly associated with cognitive decline and quality of life in women with breast cancer. Depression and anxiety increased vulnerability to cognitive impairment after chemotherapy. Nursing intervention is needed to relieve chemotherapy-related toxicity and psychological factor as well as cognitive decline for quality of life in patients undergoing chemotherapy.

• Journal of Korean Academy of Nursing
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• v.49 no.4
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• pp.437-448
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• 2019

Purpose: This study was conducted to test a path model for the factors related to undergraduate nursing students' clinical practicum stress, based on Lazarus and Folkman's stress-coping model. Methods: This study utilized a path analysis design. A total of 235 undergraduate nursing students participated in this study. The variables in the hypothetical path model consisted of clinical practicum, emotional intelligence, self-efficacy, Nun-chi, and nursing professionalism. We tested the fit of the hypothetical path model using SPSS/WIN 23.0 and AMOS 22.0. Results: The final model fit demonstrated a satisfactory statistical acceptance level: goodness-of-fit-index=.98, adjusted goodness-of-fit-index=.91, comparative fit index=.98, normed fit index=.95, Tucker-Lewis index=.92, and root mean square error of approximation=.06. Self-efficacy (${\beta}=-.22$, p=.003) and Nun-chi behavior (${\beta}=-.17$, p=.024) were reported as significant factors affecting clinical practicum stress, explaining 10.2% of the variance. Nursing professionalism (${\beta}=.20$, p=.006) and self-efficacy (${\beta}=.45$, p<.001) had direct effects on emotional intelligence, explaining 45.9% of the variance. Self-efficacy had indirect effects on Nun-chi understanding (${\beta}=.20$, p<.001) and Nun-chi behavior (${\beta}=.09$, p=.005) through emotional intelligence. Nursing professionalism had indirect effects on Nun-chi understanding (${\beta}=.09$, p=.005) and Nun-chi behavior (${\beta}=.09$, p=.005) through emotional intelligence. The variables for self-efficacy and nursing professionalism explained 29.1% of the Nun-chi understanding and 18.2% of the Nun-chi behavior, respectively. Conclusion: In undergraduate nursing education, it is important to identify and manage factors that affect clinical practicum stress. The findings of this study emphasize the importance of Nun-chi, self-efficacy, emotional intelligence, and nursing professionalism in the development of an educational strategy for undergraduate nursing students.