• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.7
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• pp.1-9
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• 2022

Peeling and dimensional deformation that occur during a manufacturing process are accompanied by an increase in the manufacturing cost and production time caused by manufacturing defects. In order to solve this problem, it is essential to predict risk factors at the design stage through computational analysis of the additive manufacturing process and to control shape distortion due to residual stress. In this study, the dimensional characteristics were improved by applying the distortion compensation design through computational analysis to minimize the distortion occurring in the DMLS(Direct Metal Laser Sintering) method of the metal additive manufacturing process.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3130-3139
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• 2022

Direct containment heating (DCH) is one of the potential factors leading to early containment failure. DCH is closely related to safety analysis and containment performance evaluation of nuclear power plants. In this study, a DCH prediction program was developed to analyze the DCH loads of containment vessel. The phenomenological model of debris dispersal, metal oxidation reaction, debris-atmospheric heat transfer and hydrogen jet burn was established. Code assessment was performed by comparing with several separate effect tests and integral effect tests. The comparison between the predicted results and experimental data shows that the program can predict the key parameters such as peak pressure, temperature, and hydrogen production in containment well, and for most comparisons the relative errors can be maintained within 20%. Among them, the prediction uncertainty of hydrogen production is slightly larger. The analysis shows that the main sources of the error are the difference of time scale and the oxidation of cavity debris.

• Korean Circulation Journal
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• v.52 no.9
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• pp.643-658
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• 2022

Cell-based therapy has emerged as a promising option for treating advanced ischemic cardiovascular disease by inducing vascular regeneration. However, clinical trials with adult cells turned out disappointing in general. As a newer approach, direct reprogramming has emerged to efficiently generate endothelial cells (ECs), which can promote neovascularization and vascular regeneration. This review provides recent updates on the direct endothelial reprogramming. In general, directly reprogrammed ECs can be generated by two approaches: one by transitioning through a plastic intermediate state and the other in a one-step transition without any intermediate states toward pluripotency. Moreover, the methods to deliver reprogramming factors and chemicals for the fate conversion are highlighted. Next, the therapeutic effects of the directly reprogrammed ECs on animal models are reviewed in detail. Other applications using directly reprogrammed ECs, such as tissue engineering and disease modeling, are also discussed. Lastly, the remaining questions and foremost challenges are addressed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.2
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• pp.178-183
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• 2012

To simulate space thermal environment in thermal vacuum test, direct or in-direct heater has been applied on the radiator. Both of them, direct heater attached on the radiator and indirect heater with a distance from the radiator, simulate the heat fluxes from the Sun radiation, the Earth IR and Albedo. They also supply the heat fluxes to the radiator of spacecraft to achieve the target temperature according to thermal test conditions. In general, indirect heater is used when the heater is not allowed to attach on the radiator directly due to constraints of coating property or contamination. For in-direct heater design, it is needed to estimate the heat power to make the extreme test conditions and minimize the interference with heat exchange of radiator and shroud. In this study, optimized thermal design of in-direct heater is proposed and investigated by commercial S/W SINDA. The effective values of design factors are also derived.

• Journal of Chest Surgery
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• v.56 no.4
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• pp.264-271
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• 2023

Background: The optimal management strategy for aortoiliac occlusive disease (AIOD) remains debatable. This study compared early and late outcomes between direct surgical bypass and kissing stents for AIOD treatment. Methods: We retrospectively reviewed data, including age, sex, risk factors, comorbidities, symptoms, TransAtlantic Inter-Society Consensus (TASC) II classification, operation time, perioperative complications, in-hospital mortality, and length of hospital stay, from a cohort of 46 patients treated for AIOD (24 with kissing stents and 22 with direct surgical bypass) at Pusan National University Hostpital from January 2007 to December 2016. The primary, assisted primary, and secondary patency rates in both groups were compared. Results: The hospital stay (direct surgical bypass vs. kissing stents: 16.36±5.19 days vs. 9.08±10.88 days, p=0.007) and operation time (direct surgical bypass vs. kissing stents: 316.09±141.78 minutes vs. 99.54±37.95 minutes, p<0.001) were significantly shorter for kissing stents. Kaplan-Meier analysis revealed that the primary, assisted primary, and secondary patency rates in the direct surgical bypass group were 95.5%, 95.5%, and 95.5%, respectively, at 1 year; 86.4%, 86.4%, and 95.5% at 3 years; and 77.3%, 77.3%, and 95.5% at 5 years. The primary, assisted primary, and secondary patency rates in the kissing stent group were 100.0%, 100.0%, and 100.0%, respectively, at 1 year; 95.8%, 95.8%, and 100.0% at 3 years; and 95.8%, 95.8%, and 100.0% at 5 years. Conclusion: Except for special cases wherein endovascular revascularization is difficult, kissing stents are more advantageous for TASC II C and D lesions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3804-3814
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• 2013

This study examined the fitness of a structural model on the relationship among biological risk disposition, sociocultural risk factors, self-control, social support, and suicidal ideation for woman adolescents. Data were collected from December 3, 2012 to March 28, 2013 by questionnaires from 343 middle and high school students in the D metropolitan city. The data was analyzed by the SPSS and AMOS programs. Biological risk disposition, sociocultural risk factors, self-control, and social support showed a direct effect on suicidal ideation for woman adolescents, while biological risk disposition and sociocultural risk factors showed an indirect effect on suicidal ideation for woman adolescents. Biological risk disposition and sociocultural risk factors showed a direct effect on self-control and social support for woman adolescents. Based on the outcomes of this study, it is necessary to design an intervention program that emphasizes the reducement of biological risk disposition, sociocultural risk factors and enhancement self-control and social support in order to prevention woman adolescents' suicidal ideation.

• Journal of the Korea Safety Management & Science
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• v.10 no.4
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• pp.21-30
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• 2008

The psychosocial stress and musculoskeletal disorders(MSDs) have been one of major health problems for hospital workers. This study tried to understand the relationship between symptoms associated with MSDs and risk factors such as working posture, job stress, psychosocial stress and fatigue. A total number of 655 hospital workers participated in this study. Specifically, REBA was applied for evaluating working posture and a checklist prepared by KOSHA(Korean Occupational Safety and Health Agency) was used for symptom survey. A questionnaire from KOSHA was also used for collecting data associated with job stress, psychosocial stress and fatigue. All these data were formulated and modeled by path analysis which was one of major statistical tools in this study. Specifically, path analysis for the data we collected came up with several major findings. The risk scores from working posture based on REBA had indirect effects via fatigue factor(MFS) as well as direct effects on symptoms. The factors associated with job stress (KOSS) and psychosocial stress(PWI-SF) had significant effects on symptoms. Specifically, indirect effect of job stress factors via fatigue factors(MFS) had bigger than that of direct effect of job stress on symptom.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.3
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• pp.295-304
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• 2019

The study aims to investigate the determinant factors in the organisation of a firm's innovative activities, and the impact of innovation capability on firm's performance of electronic firms in Ho Chi Minh city, Vietnam. How is the performance of electronic companies after delivering an innovation project? How will innovation capability affect firm's performance in electronic companies? This study aims to seek the answer of these questions. We employ a Structural Equation Model and the PLS technique in order to validate the theoretical model proposed in this study. With observation of 374 valid firms, based on Cronbach's Alpha analysis, EFA analysis, CFA analysis and SEM analysis, this study discovers 5 groups of factors including: (i) Institution factors; (ii) Attitude of leadership factors; (iii) Marketing factors; (iv) Technological resources factors; (v) Combination factors, which have direct impact on innovation capability of firms. There are 4 groups of factors that have positive impacts on financial performance of electronic firms, with descending order of importance as follows: (1) Attitude of leadership factors; (2) Quality of human resources factors; (3) Innovation capability; (4) Marketing activities factors. Research results are important implications for Government administrative agencies for business to consult and introduce effective support policies.

• Korea Journal of Hospital Management
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• v.17 no.2
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• pp.1-20
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• 2012

This study aims to suggest managerial strategies for strengthening their competitiveness via analyzing and determining factors to help improve customer orientation and internal customer satisfaction. Furthermore, this study aims to find out the factors of internal service quality affects job satisfaction and customer orientation. The data was collected in 5 small and medium hospitals on 215 workers who had direct interactions with customers. Through regression analysis, all factors of internal service quality affects job satisfaction, however only two factors, credibility and sympathy appeared to affect customer orientation.

• East Asian mathematical journal
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• v.31 no.2
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• pp.245-273
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• 2015

The purpose of this study is to investigate environmental factors that affect mathematics learning of students in multicultural families. For this study, as study subjects, eight elementary school students and one middle school student, who were born and grew up in multicultural families in Korea due to international marriage of Korean father and foreign mother, and their five mothers were selected. To examine factors affecting mathematics learning and interests of students in multicultural families, relationships with parents, friends, and teachers were surveyed, and mathematics attitude test was performed. After conducting one on one interview based on collected questionnaires and results of the attitude test, qualitative data analysis was performed. As a result of survey and interview, positive factors affecting mathematics learning of students in multicultural families included arousing interest in mathematics through mother's mathematics teaching in her mother language and direct teaching, good peer relation, teacher's compliment and encouragement, and lowering the burden of language in accordance with characteristics of mathematics course.