• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.96-104
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• 2018

Military vessels are complex weapon systems consisting of various integrated onboard equipment. Since their acquisition of military equipment takes a long period of time and a prototype ship is deployed and tested, vessel development has relied on its proprietary process. However, due to the growing complexity of onboard equipment technology, application of systems engineering (SE) process has become indispensable. Nonetheless, an effective design process complementing the existing design with the SE has not yet been developed. As such, we have studied an improved basic design process for submarines based on SE. To do so, we analyzed the processes for the basic design, technical review, and requirement management. Included reviews and requirements are SRR, SFR and PDR, and SSRS, SSS, and SSDD. By combining the results in the SE framework, we built an improved basic design process that can be applied in parallel with the SE-based technical review and requirement management. To assess the process, we applied our proposed model to the submarine development undergoing the basic design phase. It is possible to effectively manage the requirements, design artifacts and improve traceability, and also utilize them as test and evaluation materials. The SE-based basic design process is expected to be useful in other kinds of vessel design.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.331-343
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• 2019

The purpose of this study is to observe the trends of heart age of Koreans by using the predictor of heart age of the Framingham Heart Study. The subjects were 20,012 adults aged 30~74 years who were enrolled in the Korean National Health and Nutrition Examination Survey from 2005~2013. They filled in the determinants data and they had no history of cardiovascular disease (CVD). The heart age was calculated using a non-laboratory based model of prediction. The difference of heart age and chronological age, and the rate of excessive heart age over 10 years were calculated. The annual trend, the difference according to gender, the age bracket and geographic region, the heart age were all evaluated. Data analysis performed using the SAS program (version 9.3). Complex designed analysis was done. The heart age showed differences according to gender, age bracket and geographic region. The heart age is a useful comprehensive indicator for predicting the CVD events in the near future. So, it could be used for the purposes of exercising caution and guidance on CVD for administering medical care. It is strongly recommended to use heart age as an indicator for customized medical management to focus efforts on relatively vulnerable subjects and their factors for CVD. Further study on Koreans' customized heart age is needed.

• Journal of the Korea Convergence Society
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• v.10 no.6
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• pp.49-58
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• 2019

This study aims to analyze the relevance between oral health practices and oral discomforts of the elderly in an urban-rural area by surveying the elderly in welfare centers for the Elderly-continued oral health care program. The result shows that the elderly brush their teeth under regular oral care, and practice oral health life by scaling for the prevention of periodontal disease. Most of the elderly who drink alcohol have experienced implant care and tend to quit drinking after the treatment, and seemed to get their oral discomfort relieved. However, no relevance is found between implant experiences and social discomfort. Furthermore, the elderly who had bad breath expressed pronunciation, taste, pain and chewing discomfort, and social discomfort (P>.05). The educational level of the elderly did not have an impact on oral discomfort, but smoking, chewing and bad breath discomfort seemed to be related to social discomfort(P>.05). Therefore, since oral discomfort of the elderly causes social discomfort which decreases their quality of living, we recommend oral health departments of local governments to help the elderly maintain happy lives by continuing to study the practical use of reducing oral discomfort.

• The Journal of the Korea Contents Association
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• v.19 no.3
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• pp.114-125
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• 2019

The frequency of official injury of fire-fighting officers exposed to an extreme situation in disaster areas has been continuously increased. In spite of increase of injury, procedures of injury approval are complex, so the working environment of fire-fighting officers is very poor in terms of safety management. This study was, therefore, conducted to provide basic data for improvement of the injury management system for fire-fighting officers, by empirically analyzing the system for those in Busan city. The findings of the empirical analysis are as follows: first, the frequency of injury experienced by them is higher than that of other occupations; second, application for injury is not actively made; third, fire-fighting officers should bear the expense if injury is approved. On the basis of such an analysis on actual conditions, an analysis on policy factors for improving the injury management system shows; first, various high-risk matters should be considered in the review of application for injury, for improvement factors of the application for injury, while it is necessary to extend the benefit and support project for injured officers, for operation improvement factors of the injury management system, and the compensation act should be improved, for the improvement factors of the injury system. Second, it is urgent to develop damage prevention and coping education program for improving the injury management system. In addition, the simplification of administrative procedures of application for injury and the extension of benefit and support project for injured officers should be realized as soon as possible, moreover, the enhancement of directors' interest and support is also required.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.489-496
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• 2019

This paper is a study on the evaluation of loss factor of damping treatment materials to reduce the noise and vibration for panels of railway vehicles and automobiles. In order to determine the modal parameters of damping materials, beam excitation tests were carried out using different type PVC coated aluminum and steel base beam specimens. The specimens were excited from 10 Hz to 1000 Hz frequency range using sinusoidal force, and transfer mobility data were measured by using an accelerometer. The loss factors were determined by using integrated program, based on theories of Half Power Method, Minimum Tangent Error Method, Minimum Angle Error Method and Phase Change Method, which enable to evaluate the parameters using modal circle fit and least squares error method. In the case of lower loss factor and data of linear characteristics, any method could be applied for evaluation of parameters, however the case of higher loss factor or data including non-linear characteristics, the minimum angle error method could reduce the loss factor evaluation. The obtained dynamic properties of the coating material could be used for application of Finite Element Method analyzing the noise control effects of complex structures such as carbody or under-floor boxes of rolling stock. The damping material will be very useful to control the structural noise, because the obtained modal loss factors of each mode show very good effect on over $2^{nd}$ mode frequency range.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.407-415
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• 2019

The purpose of this study was to analyze the dietary habits and health risk behaviors of adolescents who experienced part-time job. For this study raw data from the 13th Youth Health Behavior Online Survey (2017) was examined. Dietary habits and health risk behaviors for 62,823 adolescents were analyzed according to the experience of part-time job. Collected data were analyzed with the SPSS 24.0 program using descriptive statistics and logistic regression analysis, to which the complex sample design was applied. The odds ratio of no fruit intake in adolescents who experienced part-time job compared to adolescents who have not experienced a part-time job was 1.20 (CI: 1.10-1.31). The odds ratio of fastfood intake in adolescents who experienced part-time job compared to adolescents who have not experienced a part-time job was 1.28 (CI: 1.19-1.38). The odds ratio of present smoking in adolescents who experienced part-time job compared to adolescents who have not experienced a part-time job was 3.48 (CI: 3.17-3.84). The odds ratio of present drinking was 3.36 (CI: 3.14-3.96). The odds ratio of high caffeine intake was 1.11 (CI: 1.04-1.19). The odds ratio of high caffeine intake was 2.29 (CI: 2.06-2.55). In developing health education programs for adolescents, it is necessary to include dietary habits and health risk behavior according to part-time experience.

• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.65-76
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• 2019

The purpose of this study was to investigate breast cancer its menopause in South Korean adult women using data from the seventh Korea national health and nutrition examination survey(KNHANES VII-2) 2017. The subjects were 3,414 people in total. The Data were analyzed by frequency, ${\chi}^2$ test and multiple logistic regression analysis using SPSS complex samples Win 25 program. According to the age of the subjects, breast cancer was 1.7% higher in women aged 50~59 years than aged 40~49 years, and 1.7% was significantly more frequent in women who had no drinking frequency than in almost everyday. Menopausal age was significantly higher in women under 44 years of age with breast cancer than in those over 50 years of age. According to menopause, postmenopausal breast cancer was 1.7% more than before menopause. When adjusted for age and alcohol drinking frequency, premenopausal adult women in Korea had significantly lower breast cancer frequency by 0.03 compared with postmenopausal women. Based on these results, it is important to pay attention to the management of breast cancer in young women aged 44 years or younger and multidisciplinary efforts are needed to reduce the ever-increasing prevalence of breast cancer.

• Journal of the Korea Convergence Society
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• v.12 no.4
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• pp.77-86
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• 2021

This study explored the role of perceived stress in Korean high school students' suicidal thought. In so doing, we also investigated the mediating role of high school students' internet use time and amount of drinking alcohol. For this, 2019 Korean adolescent health behavior survey was used. Complex design multivariage logistic regression analysis revealed that high school students' perceived stresss(OR:5.607, 95%CI:5.077-6.191) and amount of drinking(ranging from OR:1.412, 95%CI:1.159-1.720 to OR:2.325, 95%CI:1.928-2.803) played a significant role in their suicidal thoughts. Internet use time and amount of alcohol consumed were found to play a mediating role. Implications of the results are discussed. Therefore, since internet use mediated suicidal thinking among adolescents, it is necessary to develop a intervention program or message for them.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.511-519
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• 2021

Slewing bearing is applied to the transmission of rotational power of the body and turret in a special vehicle for anti-aircraft weapons that overcomes the enemy flight system approaching at low altitudes with rapid response fire. When the turret load and impact load generated when shooting are combined in performing the combat mission of a special vehicle, structural stability must be secured to achieve a successful function. Among the components of the slewing bearing, the stability of the components against the complex loads acting by the turret drive and shooting was evaluated by considering the shape and material characteristics of the ring-gear, roller, and wire-race. As a research method for stability evaluation, based on engineering theory, the strength characteristics of the components were examined by numerical calculations. Finite element analysis was performed on components using the ANSYS analysis program. The results of theoretical analysis and the results of finite element analysis were very similar. A structural stability evaluation for the slewing bearing, which was performed mainly on the analysis, confirmed that the design strength of the slewing bearing determined in the preliminary design in the early stage of localization development was sufficient.

• Nutrition Research and Practice
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• v.15 no.3
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• pp.355-366
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• 2021

BACKGROUND/OBJECTIVES: The study was performed to investigate health-related lifestyle, dietary habits, and depression according to exercise frequency to understand complex factors that affect effective health management. Thus, exercise frequency, health-related lifestyle, dietary habits, and depression were evaluated in college students in Seoul and Gyeonggi-do areas. SUBJECTS/METHODS: A survey was conducted on college students, aged 19-29, in Seoul and Gyeonggi-do areas from May 13 to May 31, 2020. A total of 594 questionnaires were collected and 566 (269 from males, 297 from females) were statistically analyzed, except 28 with incomplete responses. Collected data were analyzed using SPSS WIN 21.0 program. RESULTS: The sex distribution of the 3 groups according to exercise frequency was significantly different; the ratio of males in over 3 times/week group was significantly higher than those in 1-2 times/week group and no-exercise group (P < 0.001). The height (P < 0.001), weight (P < 0.001), and body mass index (P < 0.05) were significantly higher in over 3 times/week group compared to no-exercise group. The ratio of subjects who answered 'good' or 'very good' for subjective health condition was significantly high in the order of 'over 3 times/week' group (59.1%), '1-2 times/week' group (34.5%), and 'no-exercise' group (25.0%) (P < 0.001). The ratio for meal regularity was high as 56.6% in 'over 3 times/week' group and the ratio for irregular meals was significantly higher in 'no-exercise' group (67.2%) and '1-2 times/week' group (54.9%) (P < 0.001). Among questions on dietary habits, 'Eat meat, fish, egg or beans' (P < 0.01) and 'Eat fruit' (P < 0.01) were significantly higher in 'over 3 times/week' group compared to 'no-exercise' group. 'Drink more than 2 liters of water' (P < 0.001) was 0.70 in 'over 3 times/week' group, which was significantly higher than 0.54 in '1-2 times/week' group and 0.38 in 'no-exercise' group. Moderate depression and severe depression that need treatments were significantly lower in 'over 3 times/week' group (18.7%) compared to '1-2 times/week' group (26.0%) and 'no-exercise' group (29.7%) (P < 0.05). CONCLUSIONS: It is considered that combined intervention for exercise habits, proper dietary habits, and depression management is needed for effective health management.