• Journal of Industrial Convergence
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• v.21 no.8
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• pp.59-67
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• 2023

This study aims to examine how individual variables (motivation to participate, leadership life skills, aging awareness), interpersonal variables (relations with subjects, colleagues, and employees), and institutional variables (recognition compensation, institutional education) affect the continuity of volunteer activities. To this end, a survey was conducted on women aged 40 to 64 working at volunteer centers and local volunteer institutions in Seoul for 20 days from August 2, 2019, and a total of 300 questionnaires were distributed and 298 copies were collected, of which 180 were used for the final analysis. For data analysis, frequency analysis, descriptive statistical analysis, correlation analysis, and hierarchical regression analysis were conducted. As a result of the analysis, it was found that leadership life skills and motivation for participation, relationships with colleagues as interpersonal variables, and recognition compensation as institutional variables had a positive effect on the continuity of volunteer activities. This study aims to provide practical and policy suggestions to revitalize and maintain the continuity of volunteer activities of middle-aged women, and basic data for the development of programs to be used in the field of practice.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.105-111
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• 2013

This study aimed to identify the recognition of fire risks on their field operations among firefighters and contribute to setting up safety measures accordingly. A self-administered questionnaire were used to evaluate their recognition of job risks. About 93.4% of respondents answered they have exposed to job risks and 73.4% answered that they had high safety awareness. Our study showed that the lower service years and ranks the fire officers had, the lower relevance in statistics their awareness of the risk of the field operations and safety concerns had. The vulnerable group is those aged 20 to 39, with under 10 years of service, at a lower rank of senior fire sergeant. The study suggests coming up with the measures to motivate the officers to perform safe operations by improving their safety awareness.

• International Journal of Highway Engineering
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• v.18 no.3
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• pp.11-19
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• 2016

PURPOSES : This study supports the evidence that it is possible to rehabilitate a damaged pavement with a lane closure specifically based on the Gimcheon~Sunsan project. METHODS : The prediction results from the simulation programs were compared with field monitoring, which focused on traffic management planning, congestion (length, time, and passing speed), bypass, and user cost, among others. RESULTS : The research results showed that lane closure application and pavement repair of the aged pavement in Korea were possible, even though the prediction results were minimally different from the field monitoring. The road agency contributes to service life extension of the rehabilitated pavement using this method. CONCLUSIONS : A marginal effect caused by the lane closure was observed on travelling users or vehicles, and the user cost of pavement repair decreased. Therefore, introducing the repair method or rehabilitation in Korea is possible. Information dissemination through various media was properly done to execute the project well. Moreover, the construction area traffic utilized nearby alternative roads. Therefore, improving the repaired pavemen's service life while ensuring that the pavement management agency can provide a road with comfortable user riding quality was possible.

• Korean Journal of Human Ecology
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• v.24 no.4
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• pp.541-554
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• 2015

In this research in order to grasp the recent research trends of clothing comfort in Korea, 584 theses have been analyzed about the forms, contents and subjects of their researches which have been published in four Korean Journals from 2000 to 2012. The results are as follows: Many of the research contents were on the clothing comfort and environmental adaptation clothes in all journals. Handle, skin temperature, clothing pressure and working clothes showed the highest frequency ln the key words. The review studies were the fewest, and experimental or survey researches were largely conducted. The research forms showed the significant differences according to the research contents. The subjects were largely focused on those aged from 18 to 29, and among the research subjects on clothing comfort, female were more than male. However, in the researches on clothing quantity and clothes wearing conditions, many of them were the studies whose subjects were both men and women. The male and old subjects increased more and more. The number of the theses in the field of clothing environmentology showed the gradually increasing tendency. The most rates were the theses on clothing comfort, but as the number of those on environment adaptation clothes increased more and more, the research contents in the two fields showed much the same. Though the attention to aging and smart clothes is increasing, the research on this is very few. Therefore, it is thought that the study on this field will have to be conducted actively.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.345-348
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• 2018

The influence of various forms of Houttuynia cordata with fermented red koji as feed additives on the performance of duck livestock was evaluated through a field study. Two hundred and forty ducks (Pekins) aged 0-38 d were used. They were randomly assigned to four treatment groups (0%, 1% H. cordata powder with fermented red koji, 1% H. cordata pelleted with fermented red koji, and 1% H. cordata coated with fermented red koji) with four replicates (15 ducks per replication). Foreconomic evaluation, the data (a total of 240 duck) obtained from each treatment were applied to 10,000 ducks per treatment 38-d after the feeding trial. Overall, the results of economic evaluation were the highest in the treatment with 1% H. cordata coated with fermented red koji, followed by 1% H. cordatapelleted with fermented red koji, 1% H. cordatapowder with fermented red koji, and control. In conclusion, using 1% H. cordatawith fermented red koji as coating and pellet type duck diets might be of economic advantage for sustainable environmental management.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.352-364
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• 2007

It is essential to reduce track maintenance costs and to extend the periodic replacements of continuous welded rails based on accumulated passing tonnage. As recently train load decrease and rail joints wear down less, the periodic replacements of continuous welded rails can be extended. There are many kinds of rail damage like squat, head-check and corrugation. These can be taken nondestructive or naked eye test. So the periodic replacements of continuous welded rails based on accumulated passing tonnage were examine with focusing on a crack of rail bottom of continuous welded rail. Therefore, this study measure dynamic response of track by metro train load, it compute impact coefficient and track spring coefficient for estimating a condition of actual track system. Also, it is converted the measured stress waveform into stress frequency histogram by the rain-flow counting methods, and then the equivalence of stress is calculated. As apply s-n curve of a new welded rail, accumulated fatigue damage ratio of laid rail and remaining service lives is estimated. This study suggest a plan of the periodic replacements of continuous welded rails based on accumulated passing tonnage classified by the types of track system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.1
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• pp.27-32
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• 2014

In this paper, PZT piezoelectric ceramic specimens with 4 compositions (Zr/Ti=50/50, 53/47, 56/44, 58/42) in $Pb(Zr,Ti)O_3$ system were fabricated. We studied effects of poling strength and thermal aging on the temperature characteristics of eletromechanical coupling factor k31 of the specimens, which were poled with the DC electric fields, 1.5, 2.5 and 3.5 kV/mm respectively and thermally aged for an hour at $200^{\circ}C$. The eletromechanical coupling factor k31 of the specimen with the composition Zr/Ti= 53/47, nearest to the morphotropic phase boundary decreased the most greatly, irrelevant to the intensity of poling field, due to 1st thermal aging. And the temperature coefficient of eletromechanical coupling factor k31 was (-) in the tetragonal phase composition and (+) in the rhombohedral phase composition, which is reverse in the temperature coefficient of resonance frequency. It is interesting that eletromechanical coupling factor k31 of PZT ceramics is shown to be able to increase as temperature increase in the interval $-20{\sim}80^{\circ}C$.

• Journal of the Society of Disaster Information
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• v.13 no.3
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• pp.332-339
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• 2017

In the case of aged structures, the information of the structure is often lost after the completion of construction, and there is a great difficulty in predicting the durability life of the structure due to the lack of information on concrete formulations. In this study, the durability of concrete specimens was evaluated by various field and indoor test methods based on the core specimens collected from the field, and the durability life of the concrete structures was predicted by using the FEM analysis technique.As a result, the neutralization rate coefficient was $5.38E-6(cm^2/day)$ and the rate of progress was low. And the possibility of complex deterioration due to carbonation and salting was found to be very low.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.10
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• pp.803-806
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• 2011

1 mol% $Li_2O$ excess $0.9(Na_{0.52}K_{0.48})NbO_3-0.1LiTaO_3$ lead-free piezoelectric multilayer ceramic actuators were investigated to determine their aging properties. To reduce the thermal aging behavior, we applied a rectified unipolar electric field of 5 kV/mm to the specimen to accelerate the electric aging behavior. By employing a rectified unipolar electric field for the piezoelectric actuators, we could remove undesirable heating from the relaxation current in the motion of the ferroelectric domain. To accelerate the aging test, the applied electric fields had a frequency of 900 Hz. To have enough time for charging and discharging, we employed an accurate time constant to design the equivalent circuit model for the aging tester. To extract exact aging behavior, we measured the pseudo-piezoelectric coefficient before and after the aging process. We also measured the electro-mechanical coupling coefficient, the frequency-dependent dielectric permittivity, and the impedance to compare with fresh and aged specimen.

• Journal of the Korea Institute of Building Construction
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• v.8 no.2
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• pp.53-61
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• 2008

It is expected that the market of residential facility for retired seniors will be a new investment field for construction firms. This study describes the questionnaire survey analysis results of potential customers' demand for the facility. For comparison purpose, direct construction cost was estimated by estimation experts. In addition, a case analysis was conducted to compare direct cost and indirect project cost with the experts' estimation. According to the questionnaire survey analysis, it is observed that there were significant differences in demand between groups which are classified by the regions, living expenditures, the level of property ownership and the scales of residence. From an investor's perspective, investment decision on residential facility for retired seniors should be made considering bothe the level of returns which can be generated from the investment and the customers' needs.