• Korean Journal of Social Welfare Studies
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• v.43 no.1
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• pp.389-411
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• 2012

A new era of research has focused on examining the growth of change in drinking problems among the elderly. Thus, the purpose of the present study was two fold: (1) to investigate trajectories of drinking problems(CAGE) among the Korean elderly(age$${\geq_-}65$$); and (2) to identify the predicting factors for the intercept and the slope of alcohol problems using multi-level growth curve model. Data come from three waves(1st wave(2006)~3rd wave(2008) of the Korea Welfare Panel(KWP) study. The results indicated that the levels of drinking problems decreased over time and that age, gender, marital status, religion, poverty, self-rated health, and social relationship satisfaction were associated with the baseline CAGE. Further analysis showed that social relationship satisfaction affected the declining slope of drinking problems over time. Specifically, among those who satisfied social relationship, there was a sharp decline of CAGE over time. Overall findings highlight the importance of developing and implementing effective alcohol prevention programs for the elderly in the community settings to mitigate the harmful effects of various psycho-social stressors. Especially, programs to maintain and form healthy social support network are suggested as critical interventions for prevention as well as recovery of alcohol problems in late life.

• Korean Journal of Social Welfare Studies
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• v.49 no.2
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• pp.159-180
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• 2018

The purpose of this study is to identify the trajectories in the use time of children from community children centers and to examine the predictive factors and developmental factors related to each trajectory. The data were derived from the second stage of the Community Children Center Panel Survey using from the first wave (2014) to the third wave (2016). A total of 606 samples were selected from the forth to sixth grades of elementary school. Latent class growth model was employed to identify the trajectories, and the multinominal logistic regression and the logistic regression analysis were used to examine predictive factors and developmental factors. Main results indicated that three types of trajectory were identified: high using group, low using group, and high initial using-rapid declining group. Sex, parental supervision, and use duration were found to be significant predictors. Regarding developmental factors, children who constantly use the community children centers were more likely to increase academic performance and school adaptation. However, no significant results were found for aggression and delinquent behaviors. Based on these findings, this study have suggested the future direction of the community children center.

• 한국노년학
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• v.38 no.2
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• pp.329-349
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• 2018

The objective of this study is to examine whether there are differences in participation in social activities and the effects of social activity types on the levels of happiness of the Korean older adults by age groups. The 5th wave(2014) of the Korean Longitudinal Study of Ageing (KLoSA) was used and a total of 3,273 elderly were selected from the 5th wave, who were 65 years old and older and who were not living with their offsprings. Chi-square test, ANOVA, and hierarchical multiple regression analysis were used. The rate of participation in economic activities declined with age and the levels of participation in leisure activities was higher in the young-old group in comparison to the middle- and the oldest- old groups. The levels of participation in family activities was higher in the middle- and the oldest-old groups in comparison to the young-old group. Socializing activities and religious activities measured by the frequencies of activities were not significantly different among the age groups. The results of a regression analysis of social activity types and their effects on happiness by age groups are the followings: 1) Leisure, socializing, religious, and family activities all (with the exception of economic activities) significantly affected the level of happiness of older persons in the young-old group. 2) However, only socializing and family activities in the middle-old age group, and only family activities in oldest-old group, had a statistically significant impact on the levels of happiness. These results support that the rates of participation in the five types of social activities and their effects on the levels of happiness were different by age groups. The implication of this study was to report that needs and the interests of older individuals are different by age groups based on empirical evidences.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.5
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• pp.383-390
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• 2014

Gastrointestinal motility consists of phasic slow-wave contractions and the migrating motor complex (MMC). Eupatilin (Stillen$^{(R)}$) has been widely used to treat gastritis and peptic ulcers, and various cytokines and neuropeptides are thought to be involved, which can affect gastrointestinal motility. We performed a study to identify the effects of eupatilin on lower gastrointestinal motility with electromechanical recordings of smooth muscles in the human ileum and colon. Ileum and colon samples were obtained from patients undergoing bowel resection. The tissues were immediately stored in oxygenated Krebs-Ringer's bicarbonate solution, and conventional microelectrode recordings from muscle cells and tension recordings from muscle strips and ileal or colonic segments were performed. Eupatilin was perfused into the tissue chamber, and changes in membrane potentials and contractions were measured. Hyperpolarization of resting membrane potential (RMP) was observed after administration of eupatilin. The amplitude, AUC, and frequency of tension recordings from circular and longitudinal smooth muscle strips and bowel segments of the ileum and colon were significantly decreased after admission of eupatilin. Eupatilin elicited dose-dependent decreases during segmental tension recordings. In conclusion, eupatilin (Stillen$^{(R)}$) showed inhibitory effects on the human ileum and colon. We propose that this drug may be useful for treating diseases that increase bowel motility, but further studies are necessary.

• Korean Journal of Materials Research
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• v.11 no.12
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• pp.1028-1034
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• 2001

The 2.5 vol% TiNi/6061Al composites were fabricated by permanent mold casting. The microstructures and tensile test for the cold rolled composites with maximum 50% reduction ratio were investigated. In the case of TiNi fiber with 2mm interval in preform, the interface bonding of fabricated composites were good, interface diffusion layer of this composites was made by the mutual diffusion. Transverse section of TiNi fiber was decreased with increasing reduction ratio and longitudinal section of TiNi fiber showed multiple wave phenomenon. And the tensile strength of composites at 38% reduction ratio was the most high. In the case of over 38% reduction ratio, the decrease of the tensile strength was due to TiNi fiber rupture by excess working. The fracture mode was appeared brittle fracture with increasing reduction ratio.

• Journal of Family Resource Management and Policy Review
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• v.16 no.1
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• pp.41-66
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• 2012

Recently, Korean baby boomers, which make up approximately 15% of the total population, have begun to retire. Their economic well being is one of Korea's most important social issues. The purpose of this study was to compare the economic structure of baby boomers' households with that of the prior generation, as well as to analyze the determinants of economic satisfaction from the perspective of "work" and "child educational burden." In addition, group comparisons were made regarding economic resource allocation between baby boomers and the prior generation and within baby boomers of different work and child educational burden statuses. Data from the 2nd wave of the Korean Longitudinal Study of Ageing (KLoSA), including baby boomers and the generation prior to the baby boomers, were used. The major findings were as follows. First, the baby boomers had a different economic structure, level of economic satisfaction, and economic resource allocation when compared to the prior generation. The economic structure of baby boomers in terms of income, expenditure, savings and assets, debts, and trust in policies significantly differed from their counterparts. Second, the determinants of economic satisfaction and the propensity of resource allocation were different depending on whether they worked or had a child educational burden, respectively. Based on these empirical results, policy implications for the future economic well being of baby boomers were provided.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.1
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• pp.48-55
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• 2014

Many techniques are available for destructive and nondestructive measurement of mechanical hardness. The ultrasonic method could be widely applicable as a nondestructive technique. Many studies have examined how changes in the mechanical hardness affect the longitudinal velocity of ultrasonic waves. This approach aims to estimate the overall velocity variations in specimens. However, proper nondestructive examination techniques are needed as effective tools for analyzing the effects of heat treatment on the surface of the specimens. Therefore, in this study, the effect on the hardness of piston rods was nondestructively measured using surface ultrasonic waves. The hardness after heat treatment was investigated at various depths in the specimens, and the velocity of the surface ultrasonic waves was measured with respect to the hardness of the piston rods. In addition, finite element method simulations were performed to confirm the behavior of the waves.

• Journal of the Korean Wood Science and Technology
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• v.18 no.3
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• pp.53-68
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• 1990

This research has been executed for maximization of lumber yield and more efficient use of small diameter logs. Sample logs from thinnings carne from densed artificial stands at the Kwangnung Experimental Forests situated in the central region of Korean peninsula. Species of sample logs were obtained to execute sawing and strength test for larch, and lumber strength test in full size for pitch pine and Korean pine. A survey on sawmills consuming domestic logs was carried out to know sawmill production, costs and utilization structure of lumber as a guide to business analysis. Results showed that sawing pattern from small logs less than 15cm in diameter was necessary to cut 9cm by 9cm square per one log in order to obtain high lumber recovery and provide for wide market needs. The total lumber yield of squares plus side boards was 56 percent to 58 percent from small logs and the yield for log sweep in 30 percent decreased by 24.5 percent in sawing production, compared to yield for straight logs. In sawing efficiency, production of lumber by twin band saw could be improved 238 percent higher than lumber of the same species produced by conventional sawmilling methods, and sawing accuracy with twin band saw was much higher at the lumber production than band saw. Lumber from the small larch logs has shown 70 knots per $m^2$ on its faces and also lumber showed lots of face checkings by air drying on the yard, compared to other species. MOR in bending of lumber in full size from small logs of larch was found ranging from 380kg/$cm^2$ to 460kg/$cm^2$, resulting in 40 percent less than the strength from clear small specimens. In lumber containing knots, cross grain, etc, longitudinal stress wave speed was delayed about 48 percent by defects in lumber from both larch and pitch pine logs. The surveyed sample sawmills consumed the domestic logs at the rate of 54 percent to 84 percent in the total timber consumption, showing high consumption at mills located in the mountains.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.603-606
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• 2006

We present a study on the development of a practical and quantitative technique for the assessment of the structural health condition with using piezoceramic(PZT) sensors. The electro-impedance-based technique with the PZT patches is very sensitive for evaluation of the incipient and small damage in a high frequency range, and however the commonly traditional modal analysis method is effective only for considerably larger damages in low frequency range. The paper presents the technique in detecting and characterizing real-time damage on the specimen that is an aluminum plate fastened with bolts and nuts by different torques and as well a plate with a crack. By using the special arrangement of the PZT sensors, the required longitudinal wave is generated through the specimen. A large number of experiments are conducted and the different conditions of the specimens, i.e. the location and extent of loosening bolts, and the plate with a crack are simulated. respectively. Since fixing and loosening the loosened bolt is controlled by a torque wrench, we can control exactly the experiment of the different torques. Compared with the simulated healthy condition, we can find whether or not there is a damage in the specimen with using an impedance analyzer with the PZT sensors. Several indices are discussed and used for assessing the different simulated damages. As for the location of bolt loosening, the RMSD is found to be the most appropriate index for numerical assessment and as well the RMSD shows strongly linear relationship for assessing the extent of the bolt loosening, and the frequency peak shift ${\Delta}F$ is used to assess the cracked plate. The possibility of repeatability of the pristine condition signatures is also presented and the appropriate frequency range and interval are uniquely selected through large numbers of experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.9
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• pp.856-861
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• 2010

In this work, experiments on hybrid sounding rocket were conducted to investigate the aerodynamic characteristics and analyze longitudinal static stability. Tests were performed on 1/10 scale models of sounding rocket through Mach number ranging from 1.75 to 2.5 and for angle of attack from $0^{\circ}$ to $6^{\circ}$. Aerodynamic forces and moments were measured by means of a 4 component internal balance. With measured forces and moments, static stability characteristics of rocket were calculated. Tests were made for three models with different length to determine the effect of body length. The visualization of shock waves was carried out by Schlieren optical system to observe variations of shock waves with Mach number and angle of attack.