• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.696-701
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• 2016

Multi-stage deep drawing is a widely used industrial manufacturing process, and its applications are gradually expanding to both small products and large metallic products. The USB C-type socket used in smart phones, for example, is manufactured using oval multi-stage deep drawing. The socket is very small and slender and it requires precise manufacturing. The thickness distribution of the final product is guaranteed only if it is uniform throughout the overall process. Therefore, minimizing the height difference between long and short sidewalls after the first operation is important for this goal. An initial blank optimization was performed for an oval-type drawing process based on finite element simulations. The goal was to determine an initial blank geometry that can maintain uniform height and thickness after the first draw operation. The initial blank shape of the sheet metal was optimized, and the results show that it satisfied the conditions of minimal thickness reduction and even thickness distribution. The geometry from the optimized simulation was compared with experimental results, which showed good agreement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.302-307
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• 2016

The technology of multistage deep drawing has been widely applied in the metal forming industry, in order to reduce both the manufacturing cost and time. A battery can used for mobile phone production is a well-known example of multistage deep drawing. It is very difficult to manufacture a battery can, however, because of its large thickness to height aspect ratio. Furthermore, the production of the final parts may result in assembly failure due to springback after multistage deep drawing. In industry, empirical methods such as over bending, corner setting and ironing have been used to reduce springback. In this study, a bottoming approach using the finite element method is proposed as a practical and scientific method of reducing springback. Bottoming induces compression stress in the deformed blank at the final stroke of the punch and, thus, has the effect of reducing springback. Different cases of the bottoming process are studied using the finite element program, DYNAFORM, to determine the optimal die design. The results of the springback simulation after bottoming were found to be in good agreement with the experimental results. In conclusion, the proposed bottoming method is expected to be widely used as a practical method of reducing springback in industry.

• 한국노년학
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• v.38 no.3
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• pp.481-499
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• 2018

The purpose of this study is to examine the impacts of smartphone use on structured social network types in the Korean elderly population. Data was derived from the 2014 survey of living conditions and welfare needs of Korean older persons collected by Korea Institute for Health and Social Affairs. A total of 4,180 participants were selected for the Propensity Score Matching (PSM) analysis. Based on propensity score estimates, the 491 smartphone users (treatment group) and 491 featurephone users (control group) were matched. Ordinary Least Squares (OLS) regression analysis was conducted to examine the relationship between smartphone use and structural social network types. The results showed that among retired older adults, people using smartphone had significantly better structured social networks than those using featurephone even after controlling for covariates. Smartphone users had the higher levels of social contact and social activity. These findings suggested empirical evidence that using smartphone positively affects structured social networks, which might be used as the basis for designing intervention programs to promote social networks and social engagement of retired older adults.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.2
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• pp.28-48
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• 2019

This research is aimed at identifying the perception associated with urban regeneration and predicting policy implications of future directions by analyzing the trend of urban regeneration depicted in the mass media by utilizing SNA (Semantic-Network Analysis) techniques. As the number of articles has increased, it is noted through analysis that the interrelationships between social phenomena and issues have combined to form the meaning of urban regeneration. Overall, 'urban' and 'regeneration' keywords also appeared at different periods, with 'urban' closely related to 'regeneration' starting in 1970 when urbanization was becoming more prevalent. It was analyzed that the frequency of 'urban' appeared more frequently in the early 1990s, while the frequency of 'rural' decreased sharply. Until the 1990s, the slums and the recession that appeared as side effects of urban problem-solving policies were mostly concentrated in cities. Policy discussions were conducted with the goal of improving the physical environment of cities rather than concentrating on the surrounding rural areas. The distributions of the keywords 'development' and 'regeneration' have increased quantitatively since the 1970s, and urban polarization has exploded due to the development of the external growth of cities, mirroring the trend of accelerated environmental threats. In particular, the keywords for 'regeneration' emerged mainly related to environmental problems, which led to the need for urban regeneration, and environmentally and ecologically friendly development. The emergence of "urban," "regeneration" and "environment" as keywords having to do with urban regeneration grew in the 1990s. This suggests that urban regeneration is now linked to "environment", as that has become a social issue.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.1-12
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• 2021

This study aims to verify the mediating effect of social support in the relationship between online social relations service utilization(PC, mobile) and life satisfaction for middle-aged and Older Adults. For this purpose, the '2017 Digital Devide Survey' data collected by the National Information Society Agency was used, and among 2,300 middle-aged and Older Adults aged 55 or older, 1,488 people using the Internet were selected as the final analysis target. Then, using the structural equation, the mediating effect of social support was verified in the between online social relations service utilization and life satisfaction. As a result, it was verified that higher levels of mobile-based social relations service utilization have a positive effect on social support and life satisfaction. Also, it was confirmed that social support has a mediating effect in the relationship between the utilization of mobile-based social relations service and life satisfaction. However, the utilization of PC-based social relations services did not show to affect social support and life satisfaction. Therefore, the results of this study can be used as basic data for practical measures to increase the connection between mobile-based social relationship service education and social support promotion education for middle-aged and Older Adults. In addition, the study is meaningful in that it overcomes the limitations of measuring the use of online social relations services as one, and selects tools that are practically effective by dividing them into mobile and PC.

• Journal of Life Science
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• v.32 no.5
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• pp.391-410
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• 2022

Human microbiota is a community of microorganisms, including bacteria, fungi, and viruses, that inhabit various locations of the body, such as the gut, oral, and skin. Along with the development of metabolomic analysis and next-generation sequencing techniques for 16S ribosomal RNA, it has become possible to analyze the population for subtypes of microbiota, and with these techniques, it has been demonstrated that bacterial microbiota are involved in the metabolic and immunological processes of the hosts. While specific bacteria of microbiota, called commensal bacteria, positively affect hosts by producing essential nutrients and protecting hosts against other pathogenic microorganisms, dysbiosis, an abnormal microbiota composition, disrupts homeostasis and thereby has a detrimental effect on the development and progression of various types of diseases. Recently, several studies have reported that oral and gut bacteria of microbiota are involved in the carcinogenesis of gastrointestinal tumors and the therapeutic effects of anticancer therapy, such as radiation, chemotherapy, targeted therapy, and immunotherapy. Studying the complex relationships (bacterial microbiota-cancer-immunity) and microbiota-related carcinogenic mechanisms can provide important clues for understanding cancer and developing new cancer treatments. This review provides a summary of current studies focused on how bacterial microbiota affect gastrointestinal cancer and anticancer therapy and discusses compelling possibilities for using microbiota as a combinatorial therapy to improve the therapeutic effects of existing anticancer treatments.

• Journal of Life Science
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• v.23 no.9
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• pp.1096-1103
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• 2013

Chronic traumatic encephalopathy (CTE), which is common in athletes, is a progressive neurodegenerative disease and a long-term consequence of repetitive closed head injuries. CTE is regarded as a chronic brain syndrome due to the effects of repetitive traumatic brain injury (TBI). Because neurotrophic factors are neuroprotective in models of brain and spinal cord injuries, we examined the effects of cerebrolysin, a mixture of various neurotrophic factors, on brain pathology in a mouse model of repetitive mild TBI (rmTBI), which is a good model of CTE. Five groups were created and treated as follows: groups 1 and 2: rmTBI for 4 weeks following cerebrolysin injection for 4 weeks; groups 3 and 4: rmTBI for 8 weeks with or without cerebrolysin injection for 4 weeks; group 5: control. We found that p-tau expression was increased in the pyramidal layer of the cortex and hippocampus, particularly the CA3 region, but not in the CA1 region and the dentate gyrus (DG). Intra-tail vein administration of cerebrolysin ($10{\mu}l$ of 1 mg/ml) after/during rmTBI treatment reduced p-tau expression in both the cortex and hippocampus. Histological analysis revealed mild astrocyte activation (increased expression of glial fibrillary acidic protein (GFAP)) but not microglia activation (ionized calcium binding adaptor molecule 1 (iba-1) expression) and peripheral macrophage infiltration (CD45). Additionally, administration of cerebrolysin after rmTBI resulted in reduced astrocyte activation. These observations in rmTBI demonstrated that cerebrolysin treatment reduces phosphorylation of tau and astrocyte activation, attenuates brain pathology, and mitigates function deficits in TBI. Taken together, our observations suggest that cerebrolysin has potential therapeutic value in CTE.

• Journal of Nutrition and Health
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• v.49 no.2
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• pp.99-110
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• 2016

Purpose: The current study was conducted in order to identify health and nutritional status of Korean underweight women in their twenties by comparing with normal, overweight, and obese women. Methods: Data from the 2010~2012 Korea National Health and Nutrition Examination Survey were used in this study. Subjects were 897 women aged 20~29 years. Subjects were classified according to underweight, normal weight, overweight, and obese groups based on body mass index. Health status was assessed using data from the health questionnaire and examination. Nutritional status was assessed using data from 24-hour dietary recall and a food frequency questionnaire. Results: The underweight group had higher education and exercised less than the obese group. Means of blood chemistry and blood pressure of the underweight group did not differ from those of the normal weight group. Means of fasting glucose, insulin, lipid profiles, blood cell counts, and blood pressure in the underweight group were different from those of the overweight or obese group. Proportions of delivery, breast feeding, and irregular menstruation in the underweight group were lower compared with the other groups. Except retinol intake, means of nutrient intake did not differ among four groups. There were significant differences among four groups in the intakes of cereals and eggs and frequency of consumption of dairy products. Conclusion: The current findings showed that health and nutritional status of underweight women in their twenties did not differ from those of normal weight women. In particular, health status of underweight women in their twenties was better than that of obese women of the same ages. Further study on health and nutritional status of extremely underweight women is necessary.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.2
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• pp.52-64
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• 2014

I the recent years, Seoul, Daejeon, Changwon, and Suncheon have started to strengthen P.R. efforts on eco-brands produced by the city and to publicize as a specialized tourist city in an attempt to change their identity and image. However, there is actually a question whether the efforts of the local governments have any direct impact on satisfaction with urban living environments and the attractions of the city. The purpose of this study was to examine the awareness of residents and visitors about the attractions of Suncheon City as an eco-city and to discuss the planning criteria for the eco-city brand building and its management. The research data was collected in Suncheon City and main results of this study are as follows. The residents and the visitors investigated were satisfied with the environmental friendliness of this city and regarded it as an eco-city. As a result of asking them why they viewed the city as an eco-city, many of the residents cited diverse green tracts of land as the reason, whereas the visitors replied they were satisfied with the state of marshy areas preserved by the city. The psychological factors related to the satisfaction of the eco-city by the residents were composed of four factors, 'cultural factor', 'urban infrastructure factor', 'ecological factor' and 'scenery factor'. The visitors were composed of five factors, 'cultural factor', 'urban infrastructure factor', 'ecological factor', 'scenery factor' and 'amenity factor'. Out of the factors, the cultural factor and the urban infrastructure factor were found to exert the largest influence on the overall satisfaction of the residents and the visitors. The ISA(Importance-Satisfaction Analysis) was made, the residents and the visitors gave top priority to 'diversity of natural attractions', 'pleasant season and weather', 'beautiful scenery', 'diversity of rare animals and plants', 'diversity of parks', 'green areas and streets', 'broad ecological area' and 'the preservation of marshy areas' among the attractions of the eco-city. They placed importance on the activation of green traffic and walking environments as well, but they weren't satisfied with the state of the two in the city. Therefore there was much room for improvement in that regard.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.6
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• pp.10-27
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• 2017

Recently, the importance of recognizing the natural environment and the need for its conservation are increasing due to rapid urbanization. Suncheon Bay, designated as Scenic Site No. 41 and one of the World's Five Greatest Coastal Wetlands, is the only tideland among the tidal flats in Korea, which has salt marsh reserves. It has high conservation value from the ecological aspect. In addition to the Suncheon Bay National Garden, it provides various benefits not only to visitors but to local residents as well in terms of economics, environmental issues, and history and cultural aspects. Two million tourists visit the site annually, which has constantly highlighted the limits of ecological capacity. The valuation of the Suncheon Bay wetland is more important for the sustainability of the Suncheon Bay wetland than for its value as a tourism resource for the activation of the local economy. This study used the Logit model, which is commonly used among probabilistic choice models, to evaluate the economic value of Suncheon Bay wetland with the contingent valuation method(CVM). Applying the conservation value of the Suncheon Bay wetland to the benefit of KRW 8,200 for 1 person and 1 day, the benefit from exploration is KRW 2,050, the management and conservation value is KRW 3,034, and the heritage value is KRW 3,116. The results of this study are that benefit from the annual exploration of Suncheon Bay wetland was KRW 44.3 in billion, the management and conservation value was KRW 6.55 in billion, and the heritage value was KRW 6.73 in billion. When converted to the number of paying visitors per year, the conservation value is about KRW 177.1 billion. This study was conducted to evaluate the use and conservation aspects of the economic value of Suncheon Bay wetland. Based on the latent value of the Suncheon Bay wetland, it provides basic data about the efficient management and policy establishment of Suncheon Bay wetland. The study is significant in that the ecological sustainability of the Suncheon bay wetland and the value of non-marketable were evaluated based on the recognition of 'benefit through exploration', 'management and conservation value' and 'value of heritage'. It can be used as policy decision data on the integrated collection of the admission fee of the Suncheon Bay wetland and Suncheon Bay National Garden.