• Computers and Concrete
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• 제22권1호
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• pp.11-25
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• 2018

A numerical approach for the evaluation of the flexural response of Steel Fibrous Concrete (SFC) cross-sections with arbitrary geometry, with or without conventional steel longitudinal reinforcing bars is proposed. Resisting bending moment versus curvature curves are calculated using verified non-linear constitutive stress-strain relationships for the SFC under compression and tension which include post-peak and post-cracking softening parts. A new compressive stress-strain model for SFC is employed that has been derived from test data of 125 stress-strain curves and 257 strength values providing the overall compressive behaviour of various SFC mixtures. The proposed sectional analysis is verified using existing experimental data of 42 SFC beams, and it predicts the flexural capacity and the curvature ductility of SFC members reasonably well. The developed approach also provides rational and more accurate compressive and tensile stress-strain curves along with bending moment versus curvature curves with regards to the predictions of relevant existing models.

• 지역사회간호학회지
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• 제28권1호
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• pp.1-12
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• 2017

Purpose: The purpose of this study is to examine factors affecting quality of life among grandparents raising their grandchildren. Methods: This study carried out a secondary analysis of data from the 2014 Korean Longitudinal Study of Aging (KLoSA) and Statistics Korea. Data collected from 224 grandparents who reported raising their grandchildren were analyzed using descriptive statistics, independent t-test, ANOVA, pearson correlation coefficient, and multilevel regression analysis. Results: The mean score of the participants' quality of life was 62.63. Significant predictors of quality of life of the grandparents included subjective health status, last year's total house income, number of last year's travels, frequency of last year's movie seeing, and number of children's parks per 100,000 population. Conclusion: These results suggest that public health nurses in improving quality of life of grandparents focus on children's parks and formal social supports as community factors as well as regular exercise as an individual factor in order to be more effective.

• Journal of Mechanical Science and Technology
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• 제16권9호
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• pp.1054-1064
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• 2002

Numerical prediction of welding-induced residual stresses using the finite element method has been a common practice in the development or refinement of welded product designs. Various researchers have studied several thermal models associated with the welding process. Among these thermal models, ramp heat input and double-ellipsoid moving source have been investigated. These heat-source models predict the temperature fields and history with or without accuracy. However, these models can predict the thermal characteristics of the welding process that influence the formation of the inherent plastic strains, which ultimately determines the final state of residual stresses in the weldment. The magnitude and distribution of residual stresses are compared. Although the two models predict similar magnitude of the longitudinal stress, the double-ellipsoid moving source model predicts wider tensile stress zones than the other one. And, both the ramp heating and moving source models predict the stress results in reasonable agreement with the experimental data.

• 한국의류산업학회지
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• 제4권2호
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• pp.156-162
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• 2002

The purposes of this study were to classify somatotype was obtained from the factor scores of the upper half of body and analyze the somatometric characteristics. The sample group was drawn from boys at the ages 9 to 10 living in Pusan and Kyungsangnam-do. Data from each boy comprised 36 anthropometric measurements and 7 photographic measurements. The study reached following conclusions. 1. According to the analysis to draw somatometric factors, seven indicative factors were obtained from measurements of the upper half of body. The most significant factor "sectional size" and the second most significant factor "longitudinal size" characterized most aspects of body shape. 2. According to the analysis of somatometric characteristics by the upper half of body, they were categorized into four types; Boys in type 1 had high stature, broadest shoulders, average frame, flattest chest and quite protruded shoulder blades and belly; boys in type 2 had shortest stature, smallest frame, most sloping shoulders and flattest shoulder blades and belly; boys in type 3 had quite corpulent with average stature, rising shoulders, most protruded chest and shoulder blades and belly of protrusion close to the average; boys in type 4 had highest stature, biggest frame, broad shoulders and back, and most protruded shoulder blades and belly.

• 복식
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• 제52권2호
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• pp.115-124
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• 2002

The purposes of this study were to classify somatotype was obtained from the factor scores of the upper half of bodies and analyze the Somatometric characteristics. The sample group (hereinafter referred to as "1st age group") was drawn from bays at the ages 7 to 8 living in Pusan and Kyungsangnam-do. Data from each boy comprised 36 anthropometric measurements and 7 photographic measurements. The study reached following conclusions. 1. According to the analysis to draw Somatometric factors by the 1st age group, seven indicative factors were obtained from measurements of the upper half of bodies. The most significant factor "sectional size" and the second most significant factor "longitudinal size" characterized most aspects of body shape of boys at the ages 7 to 8. 2. According to the analysis of Somatometric characteristics by the upper half of bodies, the 1st age group was categorized into three types : Boys in type 1 had highest stature, biggest frame, broadest shoulders, most protruded chest and shoulder blades and flattest belly : boys in type 2 had shortest stature, smallest frame, sloping shoulders and most protruded belly boys in type 3 had quite high stature and his other measurements were close to the averages of this age group.he averages of this age group.

• Safety and Health at Work
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• 제5권1호
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• pp.13-16
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• 2014

Background: This study assesses influences of baseline psychological risk factors on prevalence of low back pain (LBP) at baseline and follow-up among nurses. Methods: A prospective longitudinal study was performed at two phases, baseline and 1-year follow-up among 246 nurses of university hospitals in Shahroud, Iran. A standardized Cultural and Psychosocial Influences on Disability questionnaire was used for data collection. Logistic regression was performed for analysis. Results: At the baseline of the study, 58.9% of nurses reported back pain in the previous 12 months. Age (p = 0.001), belief that work causes pain (p = 0.022), and somatization tendency (p = 0.002) significantly increased risk of LBP. At 1-year follow-up, prevalence of LBP was 45.7% and expectation of back pain at baseline (p = 0.016) significantly increased risk of LBP in this phase (p < 0.05). Conclusion: Results indicate that risk factors for prevalence of back pain at baseline and 1-year follow-up are different. At baseline, the risk factors are age, belief that work causes pain, and somatization tendency, and at follow-up, expectation of pain is the major risk factor.

• 한국직업건강간호학회지
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• 제26권4호
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• pp.247-260
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• 2017

Purpose: The purpose of this study was to investigate the individual and working environment-related factors affecting hypertension among middle-aged and elderly self-employed workers in South Korea. Methods: This was a secondary data analysis of data from the Korean Longitudinal Study of Aging (KLoSA). The study sample included 1,319 middle-aged and elderly self-employed workers who were diagnosed without hypertension and older than 45 years at Wave 1 of the KLoSA. Data were analyzed using descriptive statistics and Cox proportional hazards regression analysis using SPSS 20.0. Results: About 20% of the middle-aged and elderly self-employed workers were diagnosed with hypertension within about 8 years from the baseline. the significant predictors of hypertension among the participants were age, diabetes mellitus, body mass index, frequency of health examinations, working hours per week, the presence of regular day off, and the type of job. Conclusion: Middle-aged and elderly self-employed workers are vulnerable to work-related health problems. In order to prevent hypertension among self-employed workers, it is necessary to improve the work environment-related factors as well as individual life styles.

• Annals of Occupational and Environmental Medicine
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• 제34권
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• pp.24.1-24.13
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• 2022

Background: In modern society, depression is serious issue that causes socioeconomic and family burden. To decrease the incidence of depression, risk factors should be identified and managed. Among many risk factors for depression, this study examined socioeconomic risk factors for depression. Methods: We utilized first (2006), second (2008), and third (2010)-wave data from the Korean Longitudinal Study of Aging (KLoSA). Depressive symptom was measured with the 10-item Center for Epidemiological Studies Depression Scale, Short Form (CES-D-10) in the survey in 2008 and 2010. Three risk factors including job security, employment type and monthly income were measured in the survey in 2006. The association between risk factors and depressive symptom was analyzed by Cox proportional-hazard model. Results: We analyzed data from 1,105 workers and hazard ratios (HRs) for 3 risk factors were significant entirely. In addition, regular worker with high income group is the most vulnerable group of poor job insecurity on depression among male workers (HR: 1.73; 95% confidence interval [CI]: 1.07-2.81). Finally, HRs for 7 groups who had at least 1 risk factor had higher HRs compared to groups who had no risk factors after stratifying 3 risk factors. In the analysis, significantly vulnerable groups were total 5 groups and the group who had highest HR was temporary/daily workers with poor job security (HR: 2.51; 95% CI: 1.36-4.64). The results concerning women, regardless of job type, were non-significant. Conclusions: This study presented one or more risk factors among poor job security, low income, temporary/daily employment type increase hazard for depressive symptom in 2 or 4 years after the exposure. These results inform policy to screen for and protect against the risk of depression in vulnerable groups.

• Asian-Australasian Journal of Animal Sciences
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• 제24권1호
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• pp.17-27
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• 2011

A selection experiment for reduced residual feed intake (RFI) in Yorkshire pigs consisted of a line selected for lower RFI (LRFI) and a random control line (CTRL). Longitudinal measurements of daily feed intake (DFI) and body weight (BW) from generation 5 of this experiment were used. The objectives of this study were to evaluate the use of random regression (RR) and nonlinear mixed models to predict DFI and BW for individual pigs, accounting for the substantial missing information that characterizes these data, and to evaluate the effect of selection for RFI on BW and DFI curves. Forty RR models with different-order polynomials of age as fixed and random effects, and with homogeneous or heterogeneous residual variance by month of age, were fitted for both DFI and BW. Based on predicted residual sum of squares (PRESS) and residual diagnostics, the quadratic polynomial RR model was identified to be best, but with heterogeneous residual variance for DFI and homogeneous residual variance for BW. Compared to the simple quadratic and linear regression models for individual pigs, these RR models decreased PRESS by 1% and 2% for DFI and by 42% and 36% for BW on boars and gilts, respectively. Given the same number of random effects as the polynomial RR models, i.e., two for BW and one for DFI, the non-linear Gompertz model predicted better than the polynomial RR models but not as good as higher order polynomial RR models. After five generations of selection for reduced RFI, the LRFI line had a lower population curve for DFI and BW than the CTRL line, especially towards the end of the growth period.

• 한국과학교육학회지
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• 제19권2호
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• pp.173-184
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• 1999

본 연구에서는 우리 나라 초 중 고등학교 학생들의 과학 탐구 능력에 대한 종단적 추이를 분석하였다. 1997년에는 우종옥 등(1998)이 개발한 검사지를 사용하였으며, 1999년에는 이를 일부만 수정하여 사용하였다. 조사 대상은 성별, 지역별 등을 고려하여 표집하였다. 조사된 자료는 각각 횡단적으로 분석하고, 이를 바탕으로 학생들의 과학 탐구능력이 어떻게 변해 가는지 종단적 추이를 분석하였다. 조사 결과 초등학생들의 과학 탐구 능력은 유의미한차이가 없었으나, 중 고등학생들의 과학 탐구 능력은 유의미하게 향상된 것으로 나타났다. 학교 과학 교육의 질을 과학적으로 관리하기 위해서는 교육과정이 추구하는 교육 목표의 달성이 성공적으로 이루어지고 있는지를 국가수준에서 주기적으로 측정하여 부진의 원인을 진단하고 개선 방안을 계속 연구하여야 할 것이다.