• Journal of the Society of Naval Architects of Korea
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• v.52 no.3
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• pp.222-235
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• 2015

The purpose of this study is to suggest guidelines for riser fatigue analysis in terms of selection of reasonable analysis method. Three analysis methods (spectral, regular wave, rain-flow counting) are introduced and compared. As the riser systems give non-linear response, the time-domain analysis method is more preferred than frequency-domain analysis method. The spectral fatigue analysis method, however, is still useful for identifying fatigue prone areas. Once stress RAO is established, fatigue damage can be calculated very quickly. The regular wave method and the rain-flow counting method are more time consuming but give more exact results compare to spectral method. In case of regular wave method, a set of regular waves which represent random sea states is considered for dynamic analysis. The rain-flow counting method is the most intuitive and exact method because it refers time history stresses containing most of non-linear effects of the riser system. However, it is not common for early design stage to use rain-flow counting method because of its high cost. In this study, it was confirmed that the regular wave method is the most cost effective way in specific cases. However, if the system is highly non-linear, it seems that the regular wave method gives less accurate results than rain-flow counting method. Therefore, it is imperative that the engineers select appropriate analysis method based on design stage and given engineering period. This paper also discusses the theoretical background of each calculation method and hydrodynamic aspects of marine riser systems. A steel catenary riser (SCR) line on FPSO was considered and marine dynamic program (OrcaFlex) was used for static and dynamic analysis.

• Journal of Digital Convergence
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• v.16 no.7
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• pp.493-509
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• 2018

This study was performed to compare the effects of health behaviors, dietary habits, and psychological health on metabolic syndrome (MS) between young adults living in one-person households (OPHs) and multiple-person households (MPHs). The data from the Korean National Health and Nutrition Examination Survey (KNHANES), which was conducted in 2014 and 2016 were used. The subjects were 2,682, who were 20 to 39 years old. The data were analyzed using complex sample Rao-Scott ${\chi}^2-tests$, t-tests, and multiple logistic regression using SPSS 23.0 software. Sex, age, obesity, and subjective health status were associated with MS in young adults living in either OPHs or MPHs. Breakfast consumption frequency, eating alone, food label use, stress, and depression were associated with MS only in young adults living in OPHs. Thus, these differentiated risk factors of MS should be considered, when health promotion strategies and interventions are planned for young adults living in OPHs. Also, further studies are needed to evaluate the effectiveness of the strategies or interventions.

• Journal of the Korean Society of School Health
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• v.28 no.1
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• pp.1-9
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• 2015

Purpose: The purpose of this study is to examine the effect of sleep duration on suicidal ideation in Korean adolescents. Methods: This study used the data drawn from Korea Youth Risk Behavior Web-Based Survey in 2013. A total data of 63,301 adolescents were included in the analysis. Included variables were general characteristics, health status variables, hours of sleep, and suicidal ideation. For sample description weighted percentage and means were used. Rao-Scott ${\chi}^2$ test and simple and multiple logistic regression with dummy variables were conducted with use of SAS 9.2. Results: Among general characteristics and health status variables, gender, grade, school level, school achievement, family's economic status, living with parents, subjective health, happiness, stress, and feeling of despair were found to be significantly related to suicidal ideation. Rates of having suicidal ideation were 22.4% in the case of students with less than 5 hours of sleep and 12.9% in students with 8 or more hours of sleep. After controlling general characteristics and subjectively perceived variables, hours of sleep was still significantly related to suicidal ideation. That is, compared to adolescents with 8 hours or more of sleep, those with less than 5 hours of sleep showed significantly higher risk for having suicidal ideation (adjusted odds ratio: 1.20, p<.001). Conclusion: These findings suggest that short sleep has negative effects on psychological health in adolescents. Particularly, less than 5 hours of sleep has harmful effect on adolescents' increased risk for having suicidal ideation.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.475-485
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• 2021

This study was conducted to identify the factors affecting depression in married working women using the results of the Korean Longitudinal Survey of Women and Families(2017). The data was analyzed by application of the Rao-Scott 𝜒²-test and t-test to identify the differences in some characteristics between the group with depression and logistic regression with SPSS/WIN 25.0 There were significant differences in feelings for marriage life (p=.003), perceptions of husbands (p<.001), satisfaction with sharing of housework (p=.008), number of children (p=.027). perceived health status (p<.001), smoking (p=.012), monthly average salary (p=.021), and job satisfaction (p=.006). It will be necessary to make efforts within the family that can equally distribute marital-related tasks with their spouses and to improve the individual's perceived health status for the management of depression of married working women. It is also necessary to education on the misconception that smoking helps relieve stress.

• Journal of the Korean Society of School Health
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• v.34 no.3
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• pp.179-189
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• 2021

Purpose: The purpose of the study was to investigate health behavior changes in Korean adolescents before and during the COVID-19 pandemic. Methods: A descriptive cross-sectional design was employed. Data were obtained from the 15~16th (2019~2020) Korea Youth Risk Behavior Web-based Survey. Overall, the data of 112,251 students, 57,303 before the COVID pandemic and 54,948 during the pandemic, were included. The data were analyzed using rao-scott 𝝌²-test, t-test, ANCOVA and logistic regression analysis. Results: While sitting time for study decreased, sitting time for leisure increased in the 2020 group compared to the 2019 group. The 2020 group was more likely to skip breakfast and have a higher BMI than the 2019 group. The 2020 group was less likely to consume fruit and engage in moderate and vigorous physical activities than the 2019 group. The 2020 group was less likely to engage in CC, EC, and HTP current smoking and be exposed to secondhand smoke at home, school, and public places than the 2019 group. The 2020 group was more likely to be satisfied with sleep, but less likely to experience stress, depression, suicidal ideation, suicidal plans, and suicidal attempts than the 2019 group. Conclusion: It is necessary to reduce sedentary time, encourage physical activities, manage smoking and drinking rates continuously, and establish a network system to prevent psychological loneliness and isolation for adolescents, which requires participation of experts from the community as a whole.

• Animal Bioscience
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• v.35 no.5
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• pp.721-729
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• 2022

Objective: An experiment was conducted to determine the effects of supplementing graded concentrations of inorganic sulphur (S) without and with folic acid (FA) in maize-soybean meal diets on performance, slaughter and anti-oxidant variables, immune responses and serum protein fractions in broiler chicken. Methods: Inorganic S was supplemented at 0.05%, 0.10%, 0.15%, and 0.20% alone or in combination with FA (4 mg/kg) in basal diet (BD) containing no supplemental methionine (Met) and FA. A control group was fed with the recommended concentration of Met. Each diet was offered to 10 pens of 5 male broiler chicks (Cobb 400) and fed ad libitum from day 1 to 42. Results: The broilers fed the BD had lower body weight gain (BWG), feed efficiency (FE), higher lipid peroxidation (LP), lower activity of glutathione peroxidase (GSHPx), lower lymphocyte proliferation ratio (LPR), and reduced concentrations of total protein, albumin, and globulin in serum. Supplementation of FA and S to the BD improved the BWG (all concentrations of S) and FE (0.20% S) similar to the control group. Similarly, the combination of S and FA significantly improved the concentrations of total protein, albumin, and globulin in serum, reduced the LP and increased the activity of GSHPx and LPR. However, responses in the above parameters were related to the concentration of S in the diet. The slaughter variables and antibody titres against the Newcastle disease were not affected with the treatments. Conclusion: Based on the results, it is concluded that the combination of S (0.2%) and FA (4 mg/kg) improved the BWG and FE, similarly supplementation of these nutrients improved the concentration of protein fractions and reduced the stress (reduced LP and improved GSHPx) variables in serum and improved the cell mediated immune response (LPR) in broilers fed sub-optimal concentrations of Met in diet.

• Animal Bioscience
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• v.35 no.3
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• pp.475-483
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• 2022

Objective: Methionine (Met) is involved in methyl group transfer besides protein synthesis. As the availability is limited and cost is high for synthetic Met, reductions in its inclusion in broiler diet may be possible by supplementing the low Met diets with methyl donors (MD) like betaine (Bet), folic acid (FA), vitamin B12 (B12), and biotin (Bio). An experiment was conducted to study the effects of supplementing the MD on performance (average daily gain [ADG], daily feed intake, feed efficiency [FE]), anti-oxidant variables, immune responses and serum protein concentration in broilers fed sub-optimal concentrations of dietary Met. Methods: Maize-soybean meal diet was used as control (CD). Different MD like Bet (0.2%), B12 (0.1 mg), FA (4 mg), or Bio (1.5 mg/kg) were supplemented to basal diet (BD) having no supplemental Met. The BD without MD was kept for comparison. Each diet was fed ad libitum to 10 replicates of 25 chicks in each from 1 to 42 d of age. Results: At the end of experiment, the ADG in MD group was higher than BD and lower than CD. The FE improved with FA or Bet compared to the BD. Breast meat weight was higher in Bet compared to the BD, while it was intermediate between BD and CD in other groups. The lipid peroxidation reduced with Bio, B12, or Bet, while the glutathione peroxidase activity improved with Bio or B12 compared to the BD. Lymphocyte proliferation improved with Bet compared to the BD. The serum protein concentrations increased with FA, Bio, or Bet compared to those fed BD. Conclusion: It can be concluded that the ADG can be improved partially with supplementation of MD while the FE improved with FA or Bet. Some MD also reduced the stress indices and improved immune responses compared to the BD fed broilers.

• Korean Journal of Occupational Health Nursing
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• v.32 no.2
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• pp.79-88
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• 2023

Purpose: This study aims to identify the factors that influence the experience of falls among older adults living in the community. Methods: The study participants were 70,887 65-year-olds who participated in the 2021 Community Health Survey. The study employed the Rao-scott x 2 test to examine the variation in fall experiences based on the characteristics of the older adults. Multiple logistic regression analysis was conducted to investigate these characteristics' impact on older adults' fall experiences. Results: The proportion of subjects in fall experience was 16.6%. The factors influencing the subject's fall experience were sex (odds ratio [OR]=1.47, 95% confidence interval [CI]=1.37~1.57), age (OR=1.48, 95% CI=1.34~1.65), family structure (OR=1.23, 95% CI=1.15~1.31), body mass index (OR=1.13, 95% CI=1.06~1.20), diabetes (OR=1.12, 95% CI=1.06~1.20), depression experiences (OR=1.56, 95% CI=1.42~1.70), stress (OR=1.12, 95% CI=1.05~1.19), subjective health status (OR=1.77, 95% CI=1.63~1.92), life satisfaction (OR=1.57, 95% CI=1.41~1.76), and chewing discomfort (OR=1.29, 95% CI=1.21~1.38). Conclusion: Efforts should be made to effectively educate and develop various programs aimed at reducing falls among older adults. It is essential to emphasize the importance of continuous and active attention to falls in the older adult population.

• Analytical Science and Technology
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• v.36 no.4
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• pp.180-190
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• 2023

The presence of process related impurities in any drug or the drug product was associated with its safety, stability and efficacy. The overall literature survey proved that there is no method published on the assessment of process related impurities in brigatinib. In this study, a simple, reliable and stable HPLC qualitative method was reported for quantification of process related impurities with easy and quick extraction procedure. The impurities along with standard brigatinib was resolved on Lichrospher^® C18 (250 mm × 4.6 mm; 5 ㎛ particle size) column in room temperature using methanol, acetonitrile, pH 4.5 phosphate buffer in 55:25:20 (v/v) at 1.0 mL/min as mobile phase and UV detection at 261 nm. The method produces well resolved peaks at retention time of 4.60 min, 12.28 min, 3.37 min, 7.34 min and 8.39 min respectively for brigatinib, impurity A, B, C and D. The method produces a very sensitive detection limit of 0.0065 ㎍/mL, 0.0068 ㎍/mL, 0.0053 ㎍/mL and 0.0058 ㎍/mL for impurity A, B, C and D respectively with calibration curve linear in the concentration range of 22.5-135 ㎍/mL for brigatinib and 0.0225-0.135 ㎍/mL for impurities. The method produces all the validation parameters under the acceptable level and doesn't produces any considerable changes in peak area response while minor changes in the developed method conditions. The method can effectively resolve the unknown stress degradation products along with known impurities with less % degradation. The method can efficiently resolve and quantify the impurities in formulation and hence can suitable for the routine quality analysis of brigatinib in raw material and formulation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.3
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• pp.135-142
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• 2015

Floating offshore structures should be designed by considering the most extreme environmental loadings which may be encountered in their design life. The most severe loading on a wave-offshore wind hybrid power generation system is wave loads. The principal parameters of wave loads are wave length, wave height and wave direction. The wave loads have different effects on the structural behavior characteristic depending on the combination of wave parameters. Therefore, the process of investigation for critical loads based on the individual wave loading parameter is need. Namely, the equivalent design wave should be derived by finding the wave condition which generates the maximum stress in entire wave conditions. Through a series of analysis, an equivalent regular wave height can be obtained which generates the same amount of the hydrodynamic loads as calculated in the response analysis. The aim of this study is the determination of equivalent design wave regarding to characteristic global hydrodynamic responses for wave-offshore wind hybrid power generation system. It will be utilized in the global structural response analysis subjected to selected design waves and this study also includes an application of global structural analysis.