• 한국도로학회논문집
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• 제19권2호
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• pp.87-95
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• 2017

PURPOSES : The objectives of this study are to evaluate moisture sensitivity of various asphalt mixtures and to suggest an alternate method for the dynamic immersion test, which is used to determine the application of anti-stripping agent, by analyzing bond strength. METHODS : The bond strength of various asphalt mixtures such as hot mix asphalt, warm mix asphalt, and polymer-modified asphalt was evaluated by the ABS test. In order to characterize moisture sensitivity at different temperatures of the mixtures, the ABS test was conducted at $-10^{\circ}C$, $5^{\circ}C$, $20^{\circ}C$, $40^{\circ}C$, and $54^{\circ}C$ under both dry and wet conditions. The concept of the bond strength ratio was applied for objective moisture sensitivity analysis. Moreover, the bond strength characteristic was compared to the dynamic immersion test to suggest an alternate method to determine the application of anti-stripping agent. RESULTS AND CONCLUSIONS : Overall, the polymer-modified asphalt demonstrates the highest bond strength characteristic regardless of moisture condition and temperature. The bond strength characteristic displays a highly reliable linear relationship from $5^{\circ}C$ to $40^{\circ}C$, and the relationship could be used to predict bond strength at any intermediate temperature. Based on the analysis of bond strength and retained asphalt ratio, the bond strength value of 1254 kPa could be applied as a criterion for anti-stripping agent.

• Computers and Concrete
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• 제24권3호
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• pp.249-258
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• 2019

In order to investigate the strength recovery of fire-damaged concrete after post-fire curing, concrete specimens were heating at $2^{\circ}C/min$ or $5^{\circ}C/min$ to 400, 600 and $800^{\circ}C$, and these exposed specimens were soaked in the water for 24 hours and following by 29-day post-fire curing. The compressive strength and split tensile strength of the high-temperature-exposed specimens before and after post-fire curing were tested. The proportion of split aggregate in the split surfaces was analyzed to evaluate the mortar-aggregate interfacial strength. After the post-fire curing process, the split tensile strength of specimens exposed to all temperatures was recovered significantly, while the recovery of compressive strength was only obvious within the specimens exposed to $600^{\circ}C$. The tensile strength is more sensitive to the mortar-aggregate interfacial cracks, which caused that the split tensile strength decreased more after high-temperature exposure and recovery more after post-fire curing than the compressive strength. The mortar-aggregate interfacial strength also showed remarkable recovery after post-fire curing, and it contributed to the recovery of split tensile strength.

• 한국학교ㆍ지역보건교육학회지
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• 제24권4호
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• pp.27-37
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• 2023

Objectives: The purpose of this study was to investigate the effect of handgrip strength level on cognitive impairment in hypertensive patients. Methods: This study used the first to eighth year data of the Korean Longitudinal Study of Aging (KLoSA). Of the 10,254 respondents who participated in the basic survey, respondents were included that they were diagnosed with high blood pressure and had no cognitive impairment. The handgrip strength was based on the highest value of handgrip strength for both hands. Cognitive function using MMSE results and 23 points or less were defined as cognitive impairment. Cox models were conducted to estimate the hazard ratios (HRs) of cognitive impairment in relation to handgrip strength adjusting for covariates. Results: In the case of hypertension patients, the probability of cognitive decline decreased by 3.0% every time the maximum handgrip strength increased by 1 unit. In the analysis by age, under the age of 64 had a 1.8% decrease in the probability of cognitive decline whenever the maximum handgrip strength increased by 1 unit, and a 3.6% decrease in those over the age of 65. In the gender analysis, male had a 3.2% decrease in the probability of cognitive decline for every 1 unit increase in the maximum handgrip strength, and female had a 2.6% decrease. Conclusions: The results of this study are expected to be used as basic data for the development of interventions to prevent cognitive decline in hypertensive patients by identifying the effect of handgrip strength level on cognitive decline. It is also expected to be used as basic data for health education on the necessity of increasing muscle strength for hypertension patients in the community.

• 산업융합연구
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• 제20권12호
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• pp.187-193
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• 2022

본 연구는 신체활동 참여 대학생들의 신체이미지가 외모관리행동에 미치는 영향을 살펴보기 위해 실시하였다. 집략 무선표집법을 사용하여 6개월 이상 신체활동에 참여한 남학생 109명, 여학생 189명, 총 298명을 표집하여 분석하였다. 그 결과는 다음과 같다. 첫째, 대학생의 개인적 특성에 따라 남학생은 외모, 체력, 건강요인과 외모향상형, 여학생은 외모관리형과 대인관계형에서 높게 나타났으며, 예체능 계열이 외모, 체력에서 용돈이 많은 대학생이 신체이미지와 외모관리행동에서 영향을 미치는 것으로 나타났다. 둘째, 신체이미지는 외모관리행동에 영향을 미치는 것으로 나타났다. 신체활동을 통한 대학생의 신체이미지는 외모관리행동에 영향을 미치며 이러한 행동은 앞으로 행복한 일상생활을 영위하는데 긍정적인 연관성이 있을 것이다.

• Computers and Concrete
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• 제19권6호
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• pp.617-623
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• 2017

This work is conducted with the aim of using waste material to reserve the natural resources. The objective is accomplished by conducting experimentation and verify by modeling based on fuzzy logic. In experimentation, concrete is casted by using natural/river sand as fine aggregate and termed as control specimen. Natural sand is conserved by replacing it with used foundry sand (UFS) by an amount of 10, 20 and 30% by weight. Fresh and hardened properties of concrete are investigated at different ages. It is observed that compressive strength and modulus of elasticity reduced with the increase in amount of UFS. Furthermore, concrete compressive strength is predicted by using fuzzy logic model and verified at different replacement ratio and age with experimental observations.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 2부
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• pp.35-37
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• 2011

This study was a comparison result between the laboratory and mock up test to apply the ultra high strength concrete to CFT(Concrete Filled Tube) structure. The investigated result of tendency and quality similarity of each specimen, was set up a management range according to checking the validity and suitability analysis. Also, It wil be utilized to data as construction guidelines of CFT.

• 가정과삶의질연구
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• 제23권6호
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• pp.25-37
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• 2005

The purpose of this study was to explore the relationship between family strengths and teacher-efficacy among married female teachers. The findings are as follows: First, the average value of family strength was 3.98 on a five-point Likert scale, which meant that they perceived themselves as having a relatively high-level of family strength. Second, the average value of leather-efficacy was 3.14 on a five-point Likert scale, which the teachers' perceptions of their own efficacy were also relatively high. 'The subjective economic status affected the level of the family strength, whereas the leather-efficacy was affected by age, years in teaching, duration of marriage, and the age of the eldest child. Finally, the variables that influenced their techer-efficacy were positive communication, social connectedness, and the age of the eldest child.

• Journal of the Korean Data and Information Science Society
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• 제21권5호
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• pp.935-944
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• 2010

In this paper, we develop the noninformative priors for the reliability in a stress-strength model where a strength X and a stress Y have independent exponential distributions with different scale parameters and a common location parameter. We derive the reference priors and prove the propriety of joint posterior distribution under the general prior including the reference priors. Through the simulation study, we show that the proposed reference priors match the target coverage probabilities in a frequentist sense.

• Computers and Concrete
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• 제30권1호
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• pp.33-42
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• 2022

Experimentally predicting the compressive strength (CS) of concrete (for a mix design) is a time-consuming and laborious process. The present study aims to propose surrogate models based on Support Vector Machine (SVM) and Gaussian Process Regression (GPR) machine learning techniques, which can predict the CS of concrete containing nano-silica. Content of cement, aggregates, nano-silica and its fineness, water-binder ratio, and the days at which strength has to be predicted are the input variables. The efficiency of the models is compared in terms of Correlation Coefficient (CC), Root Mean Square Error (RMSE), Variance Account For (VAF), Nash-Sutcliffe Efficiency (NSE), and RMSE to observation's standard deviation ratio (RSR). It has been observed that the SVM outperforms GPR in predicting the CS of the concrete containing nano-silica.

• 지역사회간호학회지
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• 제26권4호
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• pp.405-414
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• 2015

Purpose: The purposes of this study were to examine the effects of home visit healthcare using a complex program on community-dwelling frail elders' physical strength, frailty, and depression and to compare the effects among three regions. Methods: This study was conducted as a quasi-experimental study using one-group pretest-posttest design. A total of 86 subjects were sampled from three regions (metropolis, small city, and rural area). The program was applied for 14 weeks. This program consisted of disease management by a visiting nurse, exercise with a visiting nurse, self exercise, telephone monitoring, health education, counseling, providing handbook, and incentive. Physical strength was measured by balance, upper-limb, and lower-limb muscle strength. Frailty was measured by the Korean Frail Scale and depression was measured by the Geriatric Depression Scale. Paired t-test and ANCOVA were used to analyze the effects. Results: Physical strength, frailty, and depression were significantly improved after applying the complex program. There were not differences among the regions. Conclusion: Home visit healthcare using a complex program was effective in improving frail elders' physical strength, frailty, and depression. There were not differences among the regions. Therefore, home visit healthcare using a complex program needs to be expanded to other regions.