• International Journal of Precision Engineering and Manufacturing
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• v.8 no.3
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• pp.50-53
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• 2007

Improving the reliability or long-term dependability of a system requires a different approach from the previous emphasis on short-term concerns. The purpose of this paper is to present a reliability evaluation method for an oil cooler intended for high-precision machining centers. The oil cooler system in question is a cooling device that minimizes the deformation caused from the heat generated by driving devices. This system is used for machine tools and semiconductor equipment. We predicted the reliability of the system based on the failure rate database and conducted the reliability test using a test-bed to evaluate the life of the oil cooler. The results provided an indication of the reliability of the system in terms of the failure rate and the MTBF of the oil cooler system and its components, as well as a distribution of the failure mode. These results will help increase the reliability of oil cooler systems. The evaluation method can also be used to determine the reliability of other machinery products.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.105-106
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• 2015

As the Long-life certification system is recently introduced in the Housing Law in Korea, it is expected that an application of the lightweight wall panel will be increased in apartment construction as the main wall system. However, the performance criteria for lightweight wall is in the early phase of its action. Therefore, it is necessary to establish the performance criteria properly by investigating performance requirement in the user's perspective. The purpose of this study is to identify of the weight of the required performance items for the lightweight wall in apartment house. To analyze the priority in the performance, an interview survey is performed; after monitering the test-bed of the lightweight walls, user and experts evaluate the performance requirements. The weight of the performance requirement is developed by AHP method.

• Corrosion Science and Technology
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• v.17 no.5
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• pp.211-217
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• 2018

Natural degradation of grounding-electrode in soil environment should be monitored for several decades to predict the lifetime of the grounding electrode for efficient application and management. However, long-term studies for such electrodes have many practical limitations. The conventional accelerated corrosion test is unsuitable for such studies because simulated soil corrosion process cannot represent the actual soil environment. A preliminary experiment of accelerated corrosion test was conducted using existing test standards. The accelerated corrosion test that reflects the actual soil environment has been developed to evaluate corrosion performances of grounding-electrodes in a short period. Several test conditions with different chamber temperatures and salt spray were used to imitate actual field conditions based on ASTM B162, ASTM B117, and ISO 14993 standards. Accelerated degradation specimens of copper-bonded electrodes were made by the facile method and their corrosion performances were investigated. Their corrosion rates were calculated to $0.042{\mu}m/day$, $0.316{\mu}m/day$, and $0.11{\mu}m/day$, respectively. These results indicate that accelerated deterioration of grounding materials can be determined in a short period by using cyclic test condition with salt spray temperature of $50^{\circ}C$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.181-182
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• 2015

The use of non-bearing light weight wall has increased recently due to the increase of high-rise buildings and supply of long-life housing. Light weight wall has advantages such as reducing the self-weight of the building, convenience in installation, and shortening construction period, however, must have a sufficient strength to external force. This study standardized the impact resistance test method for light weight walls by using the actual impact load obtained through load analysis test in previous studies. The impact resistance test method was divided into the test method that uses soft body and the one that uses hard body. The size of specimen was set up as height 2.4m and width 3.0m. The size and shape of the body followed those used in BS 5234-2 and so on for the compatibility with the test method used overseas. The judgment criteria for impact resistance based on test results were not defined uniformly as the assessment of functional damage can vary depending on the type of material, structural method, purpose of wall, and so on even when the same impact load was applied.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.41-47
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• 2009

In this paper, the long-term performance of highway embankment using tire shred-sandy soil mixture as a lightweight fill material was evaluated through the field monitoring and field test programs. A tire shred-sandy soil embankment was constructed to support a four-lane highway in Indiana, which was built with a 50 : 50 volumetric ratio of tire shreds (maximum particle dimension of 76 mm) and sandy soil (SP, USCS). After opening of the road for traffic, no noticeable differential settlement and lateral deformation were observed, and no adverse environmental impact on temperature was detected as a result of the construction of the tire shred-sandy soil embankment. Moreover, FWD test results showed that tire shred-sandy soil mixture provides bearing capacity comparable to that of conventional fill and meets the criterion for a design life of 20 years.

• Journal of Fashion Business
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• v.18 no.2
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• pp.66-79
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• 2014

The purpose of this study was to find out the difference between preferred hairstyle and pursued-image of hairstyle according to demographic characteristics. The method of this study is a content analysis and survey research using a questionnaire, which consisted of items of pursued-image of hairstyle, preferred hairstyle and demographic characteristics. 450 women were selected as subjects of this study; they were randomly selected from hair salon located in Seoul, Inchon and Bundang. For the material analysis, We used the statistical program of SPSS 12.0; frequencies, factor nalysis, one-way ANOVA and Duncan's multiple range test, T Test and ${\chi}^2$ Test were carried out as the methods of analysis. The research findings were as follows. First, the results of hairstyles according to the content analysis usually resulted 5 hairstyles, such as cuts and crew cut, bobbed hair, long layered hair styles and nonelayered long hair styles. Second, under the survey regarding the difference of preferred hairstyle and pursued-image of hairstyle according to demographic characteristics. variety of hair styles due to the subjects were more willing to try a consciousness about other's suggestions and how they are portrayed. Moreover a low level of education was ralated to a attempting a variety of styles, considering their social life. Subjects with higher age, education level and salary preferred a glamorous image as well as crew cuts. Which made them look younger. However, when they were younger, they preferred long nonelayered hair styles. In conclusion, age, average monthly income and education level are important variations affecting the property of change in hairstyles and pursued-image of hairstyles.

• Journal of People, Plants, and Environment
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• v.23 no.5
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• pp.565-576
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• 2020

Background and objective: The elderly living in homeless living facilities for a long time suffer from various mental health problems. This study aims to determine the psychological, emotional, and social effects of a horticultural therapy program composed of gardening activities, which was designed based on the semantic structures of life for the homeless elderly living in the facilities for a long time. Methods: A total of 12 subjects (6 in the control group and 6 in the experimental group) participated in the study. The horticultural therapy program consisted mainly of gardening activities, and a total of 16 sessions were conducted once a week for 16 weeks, 60-90 minutes per session. The subjects were tested to evaluate their self-esteem, depression, and horticultural activities. The data were analyzed using the Mann-Whitney U test, Wilcoxon rank test, and Friedman test, which were nonparametric tests, conducted at a 95% significance level. Results: First, in the case of self-esteem, a significant difference was found between the groups, 20.00 points (SD = 5.69) in the control group, and 25.50 points (SD = 3.73) in the experimental group (p = .034). Second, in the case of depression, no statistically significant difference was found in the posttest. Finally, in the case of the horticultural activity evaluation, the scores of most variables gradually and significantly increased during the program [Verbal interaction during activity (p = .006), Self-concept and identity (p = .006), Need-drive adaptation (p < .001), Interpersonal and social relations (p < .001)]. Conclusion: These results support that the horticultural therapy program could help the elderly improve psychological relaxation, emotional stability, and social relationships. In order to generalize the results, it is suggested to increase the number of subjects or conduct additional repetitive experiments in further research.

• Journal of Welding and Joining
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• v.28 no.1
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• pp.77-85
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• 2010

Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. Gas welding is very important and useful technology in fabrication of a railroad car and vehicles structure.However fatigue strength of the gas welded joints is considerably lower than parent metal due to stress concentration at the weld, fatigue strength evaluation of gas welded joints are very important to evaluate the reliability and durability of railroad cars and to establish a criterion of long life fatigue design. In this paper, $({\Delta}{\sigma}_a)_R-N_f$ curve were obtained by fatigue tests. Using these results, the accelerated life test(ALT) was conducted. From the experimental results, an acceleration model was derived and acceleration factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of plug and ring gas welded joints and data analysis by statistic reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.1
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• pp.1-10
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• 2001

Since the Industrial Revolution, people have enjoyed an abundant life, owing to the technological innovations of science. However, because of changes in the environment or polution to the environment, it has brought on many chronic diseases. Especially, even though it may be a small amount, if cadmium gets into a human body, because its biological half life is long, it fatally causes a kidney disease and damage to human organisms. It was reported that Metallothioneins(MT), a substance that is closely related with a free radical that comes from environmental pollution and the course of which cadmium, which causes chronic addition in the body, is formed, along with harmful metals, make the toxicity reduce. MT compound led into the body by cadmium indirectly functions as an antioxidation, supplied adequate amount of vitamin E, and suppresses the accumulation of cadmium in heart, liver and blood. Cadmium content found in Korean soil according to the test conducted from 1992 to 1996 was 0.02~0.03mg/kg in cereals, pulses, and potatoes. Free radical scavenger, finding solution for metal substance that comes from environmental pollution from food and natural substances implicates a better future for the study of food science.

• Journal of Korean society of Dental Hygiene
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• v.11 no.4
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• pp.475-487
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• 2011

Objectives : The growing elderly population and social changes have fueled a rapid increase in demand for elderly care facilities, but health care services for the elderly, especially oral health services, have long been overlooked. The purpose of this study was to examine the oral health care of elderly residents in elderly care facilities in an effort to provide some information on the elderly's oral health care and the development of dental care programs geared toward institutionalized elderly people. Methods : The subjects in this study were 230 elderly people who were in elderly care facilities in Jeolla Province. An individual interview was held, and they got a dental checkup. As for data analysis, t-test and ANOVA were utilized, and Scheffe post-hoc test was employed. Results : 1. In relation to the subfactors of the quality of life related to oral health, the elderly people investigated got a mean of 4.58, 4.47, 4.38, 4.09, 3.94, 3.91 and 3.76 respectively in activity disorder, mental disorder, social disorder, mental inconvenience, functional disorder, physical pain and physical disorder. 2. Concerning the overall quality of life related to oral health, there were statistically significant gaps in this aspect according to gender, age, presence or absence of systemic disorder, presence or absence of eating difficulties, subjective health status, subjective oral health state and oral health concern. 3. The presence or absence of root caries had a significant relationship to physical pain and social disorder among the subfactors of the OHIP-14, but that had nothing to do with functional disorder, mental inconvenience, physical disorder, mental disorder and activity disorder. Conclusions : The oral health indexes of the institutionalized elderly people in Jeolla Province were measured, and what factors affected the subfactors of oral health was checked. As a result, there appeared a close relation ship between oral health and the quality of life. Therefore effective oral health plans that cater to the elderly should be carried out to improve elderly people's quality of life related to oral health who stay in long-term elderly care facilities. In the future, prolonged research should be implemented from diverse angles for the sake of institutionalized elderly people.