• Structural Engineering and Mechanics
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• 제76권3호
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• pp.337-354
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• 2020

Reinforced concrete beam-column (RCBC) joints of laterally loaded unbraced frames are sometimes controlled by their shear behavior. This behavior relies on multiple and interdependent complex mechanisms. There are already several studies on the influence of some parameters on the shear strength of reinforced concrete joints. However, there are no studies methodically tackling all the most relevant parameters and quantifying their influence on the overall joint behavior, not just on its shear strength. Hence, considering the prohibitive cost of a comprehensive parametric experimental investigation, a nonlinear finite element analysis (NLFEA) was undertaken to identify the key factors affecting the shear behavior of such joints and quantify their influence. The paper presents and discusses the models employed in this NLFEA and the procedure used to deduce the joint behavior from the NLFEA results. Three alternative, or complementary, quantities related to shear are considered when comparing results, namely, the maximum shear stress supported by the joint, the secant shear stiffness at maximum shear stress and the secant shear stiffness in service conditions. Depending on which of these is considered, the lower or higher the relevance of each of the six parameters investigated: transverse reinforcement in the joint, intermediate longitudinal bars and diagonal bars in the column, concrete strength, column axial load and confining elements in transverse direction.

• 국제강구조저널
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• 제18권4호
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• pp.1363-1372
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• 2018

Recently, there have been studies about the increasing effect on the local plate buckling strength of flat plates when longitudinally stiffened with closed-section ribs and an approximate solution to quantitatively estimate these effects were suggested for flat plates. Since there are few studies to utilize such increasing effect on curved panels and a proper design method is not proposed, thus, this study aims to numerically evaluate such effect due to the rotational stiffness of closed-section ribs on curved panels and to propose an approximate method for estimating the buckling strength. Three-dimensional finite element models were set up using a general structural analysis program ABAQUS and a series of parametric numerical analyses were conducted in order to examine the variation of buckling stresses along with the rotational stiffness of closed-section ribs. By using a methodology that combine the strength increment factor due to the restraining effect by closed-section ribs and the buckling coefficient of the panel curvature, the approximate solutions for the estimation of buckling strength were suggested. The validity of the proposed methods was verified through a comparative study with the numerical analysis results.

• Journal of Korean Neurosurgical Society
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• 제64권4호
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• pp.495-504
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• 2021

Three-dimensional printing (3DP) applications possess substantial versatility within surgical applications, such as complex reconstructive surgeries and for the use of surgical resection guides. The capability of constructing an implant from a series of radiographic images to provide personalized anatomical fit is what makes 3D printed implants most appealing to surgeons. Our objective is to describe the process of integration of 3DP implants into the operating room for spinal surgery, summarize the outcomes of using 3DP implants in spinal surgery, and discuss the limitations and safety concerns during pre-operative consideration. 3DP allows for customized, light weight, and geometrically complex functional implants in spinal surgery in cases of decompression, tumor, and fusion. However, there are limitations such as the cost of the technology which is prohibitive to many hospitals. The novelty of this approach implies that the quantity of longitudinal studies is limited and our understanding of how the human body responds long term to these implants is still unclear. Although it has given surgeons the ability to improve outcomes, surgical strategies, and patient recovery, there is a need for prospective studies to follow the safety and efficacy of the usage of 3D printed implants in spine surgery.

• 한국보육지원학회지
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• 제17권4호
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• pp.111-128
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• 2021

Objective: The purposes of this research are to analyze former research papers regarding Dream Start according to academic field in an attempt to better understand their services and to present additional directions. Methods: The 66 research papers regarding Dream Start from 2008 to 2020 were analyzed by three categories: welfare, child care(education) and health. In each category, this research analyzed the research papers by year, research type, research subject and the research topic. Results: First, the research papers regarding Dream Start were most actively published between 2010 and 2017 and the number of research papers decreased after 2018. Second, the results regarding the type of study showed that quantitative studies were mostly performed in all, but the detailed methods used mainly differed. Third, the subjects of the study commonly included guardians. Fourth, the research topics were focused on business content, operations, and direction. Conclusion/Implications: Based on these results, welfare, child care(education) and health sectors need to make more efforts for balanced development, and integrated research and longitudinal studies are necessary. Second, further research is needed to enhance the professionalism of teachers and nurses working in the Dream Start. Third, more research is needed for the integration and coordination of resource management.

• Safety and Health at Work
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• 제13권1호
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• pp.51-58
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• 2022

Introduction: Previous studies on occupational health focussed predominately on the occurrence of occupational diseases. Relatively few studies have measured how employment is associated with the use of healthcare services. This study investigates the association between employment and the extent and range of healthcare use, such as medical expenditures, of women in South Korea. Methods: We analyze data of the Korean Health Panel, an ongoing longitudinal national representative survey, from 2008 to 2017, to identify the status of economic activity of women by year and age group. We estimate the association between female employment status and medical expenditures by using random effect panel Tobit models. Furthermore, we investigate the association between employment status and the range of healthcare services in biomedicine and traditional Korean medicine (KM) by conducting conditional fixed-effects logistic regression analyses. Results: For women aged between 25 and 65 in 2017, the majority of them were employed or self-employed. (The proportion of employment of self-employment equals 64.80%). In addition, working women spent 11.6% less on healthcare than nonworking women, and self-employment lowered the healthcare expenditure by 13.1%. Neither work nor the type of work is related to the types and range of healthcare service use. Being employed or self-employed is negatively associated with women's expenditure on healthcare. Conclusions: The findings show that employment is associated with less spending on healthcare. They imply that employment has a positive impact on women's health.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권5호
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• pp.259-266
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• 2022

The relationship between obstructive sleep apnea (OSA) and diverse types of pain conditions have been proposed. However, no consensus on the relationship between OSA and painful temporomandibular disorders (TMDs) has been established. Therefore, this systematic review has been conducted to review the existing literatures and provide comprehensive synthesis of such literatures about OSA and painful TMDs using the evidence-based methodology. A literature search was conducted using two electronic databases, Scopus, and PubMed. Risk of bias was assessed using the risk-of-bias assessment tool for non-randomized study version 2.0. A total of 158 articles were screened from the initial search and eventually, 5 articles were included in this systematic review. One study adopted both the longitudinal prospective cohort and case-control designs and other 4 articles adopted the cross-sectional design. Two studies employed polysomnography (PSG) for the diagnosis of OSA and mentioned the results from the PSG. All cross-sectional studies demonstrated higher OSA prevalence among patients with TMD, and one cohort study suggested OSA as a risk factor for TMD. OSA appears to have potential influences on the development of TMD; however, the role of TMD in the development of OSA remains to be unknown owing to the lack of high-quality evidences.

• The Korean Journal of Pain
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• 제36권2호
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• pp.230-241
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• 2023

Background: This study aimed to determine the prevalence of chronic pain and its contributing factors among teenagers aged 12-21 years in Shiraz, Iran. Methods: This cross-sectional study was conducted on adolescents aged 12-21 years. Demographic variables of the adolescents and their parents as well as the pain characteristics were assessed. Descriptive statistics, multinomial logistic regression, and regression models were used to describe the characteristics of the pain and its predictive factors. Results: The prevalence of chronic pain was 23.7%. The results revealed no significant difference between the male and female participants regarding the pain characteristics, except for the home medications used for pain relief. The results of a chi-square test showed that the mother's pain, education, and occupation, and the father's education were associated significantly with chronic pain in adolescents (P < 0.05). Multinomial logistic regression also showed the mother's history of pain played a significant role in the incidence of adolescents' chronic pain. Conclusions: The prevalence of chronic pain was relatively high in these adolescents. The results also provided basic and essential information about the contributing factors in this area. However, consideration of factors such as anxiety, depression, school problems, sleep, and physical activity are suggested in future longitudinal studies.

• 의학교육논단
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• 제25권2호
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• pp.119-125
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• 2023

Pusan National University School of Medicine (PNUSOM) began analyzing the cohort of pre-medical students admitted in 2015 and has been conducting purposeful analyses for the past 3 years. The aim of this paper is to introduce the process of cohort establishment, cohort composition, and the utilization of cohort analysis results. PNUSOM did not initially form a cohort with a purpose or through a systematic process, but was able to collect longitudinal data on students through the establishment of a Medical Education Information System and an organization that supports medical education. Cohort construction at our university is different in terms of a clear orientation toward research questions, flexibility in cohort composition, and subsequent guideline supplementation. We investigated the relevance of admission factors, performance improvements, satisfaction with the educational environment, and promotion and failure rate in undergraduate students, as well as performance levels and career paths in graduates. The results were presented to the Admissions Committee, Curriculum Committee, Learning Outcomes Committee, and Student Guidance Committee to be used as a basis for innovations and improvements in education. Since cohort studies require long-term efforts, it is necessary to ensure the efficiency of data collection for graduate cohorts, as well as the validity and ethics of the study.

• 한국의류학회지
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• 제38권6호
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• pp.913-928
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• 2014

This study estimated a dual path model to predict consumers' intention to use a QR code virtual store by the effect of a mobile transaction system and a facilitating condition that also examined the role of experience and the use of an intention model in the context of a QR code virtual store. A longitudinal field study was conducted at selected QR code virtual stores. A questionnaire containing mobile transaction system, facilitating condition, performance expectancy, effort expectance, and intention to use was administered at two different points in time: Initial use (T1) and the second use after one month (T2). This study sampled 109 subjects who voluntarily participated in field studies twice at different time points (pooled sample=218). Participants were asked to visit at the QR code virtual store and undertake shopping tasks on their smartphones. The estimated dual path model showed that a mobile transaction system had a positive effect on performance expectancy, which influenced intention to use; however, facilitating condition had a positive effect on effort expectancy, but the effort expectance did not lead to intention to use. The effort expectance significantly also affected the performance expectance influencing intention to use QR code virtual stores. It was also found that use experience moderated the effect of mobile transaction systems on performance expectancy. The findings discussed a critical and success factor in consumer technology acceptance and use over time. A managerial implication was also discussed to capture potential users by emphasizing performance expectancy with the superiority of an innovative system or consumer facilitating condition as external resources in the introduction stage of new technology.

• Child Health Nursing Research
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• 제24권4호
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• pp.496-505
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• 2018

Purpose: The purpose of this study was to examine changes in the self-rated health of adolescents and to identify its predictors using longitudinal data from the KCYPS. Methods: A sample of 2,351 adolescents who were in the first grade of middle school in 2010 was analyzed. The study employed latent growth analysis using data from 2010 to 2016. Results: Results indicated that self-rated health of adolescents increased, following the form of a linear function. The analyses revealed that adolescent self-perception of health were conceptualized not only by their health-related behaviors, but also by personal, socioeconomic and psychological factors. Specifically, physical activity, passive leisure time activities, gender (initial: b=-.060, slope: b=.030), place of residence (initial: b=-.079), self-rated economic condition (b=.098), working status of mother (b=.016), monthly family income (b=-.001), aggression (b=.061), depression (initial: b=-.104, slope: b=.012), stress (initial: b=-.172, slope: b=.014, ego-resiliency (initial: b=.197, slope: b=-.021), and self-esteem (initial: b=.106, slope: b=-.017) had significant effects on the overall linear change of self-rated health (p<.05 for all estimators above). Conclusion: The findings of this study suggest that adolescents' self evaluation of their health is shaped by their total sense of functioning, which includes individual, health-related behavioral, socioeconomic, and psychological factors.