• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.66-66
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• 2009

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.224-224
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• 2004

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.107-112
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• 1998

A great deal of time and effort are required to evaluate the safety and durability of a vehicle structure in the vehicle development stage. It is difficult to find the reasons for cracks which occur in the body and frame of a vehicle during tests. Recently computer aided engineering techniques have been utilized to solve the problems of safety and durability of vehicles. In this study, a dynamic stress analysis is performed on the frame of the vehicle by rigid and flexible multibody dynamics techniques. The result of the analysis is compared to that of the actual test. The full vehicle dynamic models for the rigid and flexible bodies are developed by DADS package. The modal coordinate system is used to save time for the dynamic stress analysis. The flexible multibody dynamic models have 12 normal modes considering the flexibility of the frame. Dynamic stresses arc calculated by relating the stress influence coefficients and the applied forces.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.1
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• pp.13-16
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• 2022

The use of animals heavily impacts the mental health of researchers performing the animal experiments. The animal researchers need to take care of animals but also give pain and sacrifice them at the same time. This circumstance can cause a variety of mental stress to the researchers. The stress generated in the laboratory would not only negatively affect the management of animals and the research results, but also would harm the researchers' physical and mental health. Because the feeling of sympathy for animals is a natural feature of humanity, psychological stress following a laboratory animal's death after use is not surprising. It is necessary to revise the relevant laws based on understanding the difficulties of animal researchers in society and to develop related educational programs at the national level to help the psychology and emotions of researchers who conduct animal experiments.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.734-741
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• 2008

At-rest and active earth pressure in plane strain condition have been applied to the design of cylindrical retaining walls. But many researchers have indicated that the earth pressure on the cylindrical retaining walls would be smaller than in plane strain condition due to wall deformation and stress relief. In this paper, the distribution of earth pressure acting on diaphragm wall of a shaft in dry sand was predicted by using the convergence confinement method and model test was performed to verify the estimated values. Test results showed that the earth pressure acting on the diaphragm wall of a shaft was expected to be 1.1~1.5 times larger than active earth pressure of plane strain condition and 0.7~0.9 times less than at-rest earth pressure.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1614-1616
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• 1998

Insulation performance of major components of prefabricated joint such as epoxy insulation unit and premolded rubber cone are guaranteed by material selection design and proper manufacturing. On the other hand insulation performance of the interfaces between the premolded rubber cone and the epoxy insulation unit and the cable insulation is maintained by keeping the premolded rubber cone to close contact with such insulation by spring. Electric characteristics of a interface depend on the contact pressure, but the required characteristics are assured so far as a proper contact pressure is maintained. In this report, the interfacial pressure by pressure sensors both in the early stage and after heating cycle were measured and the simulation by FEM program were presented. The comparison of these two results show that interfacial pressure could be controlled optimally by changing the spring length and lubricant state of the interface.

• Journal of Agricultural Extension & Community Development
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• v.28 no.1
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• pp.13-23
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• 2021

This study aims to examine the market segmentation of rural healing tourists. A two-stage cluster method was used to segment the market of rural healing tourists, and the difference in satisfaction by segmented market was identified. In this study, a total of 433 cases were used for analysis. A total of four clusters of rural healing tourists were derived based on the purpose of visit and involvement with rural healing tourism. The names of each cluster were determined as 'high involvement, daily escape purpose type', 'high involvement, stress relief purpose type', 'low involvement, daily escape purpose type', and 'high involvement, exotic experience purpose type.' Each groups were found to have significant differences according to educational level, purpose of visit, companion, and expenditure. The satisfaction and the behavioral intention of rural healing tourists was highest in the group of 'high involvement, stress relief purpose type.' The results of this study suggest that the characteristics and satisfaction of rural healing tourists were differ according to the segmented group. This study suggests useful information for target marketing strategies for each segmented market according to the characteristics of rural healing tourists.

• Journal of Korean Society for Quality Management
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• v.51 no.4
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• pp.735-749
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• 2023

Purpose: The purpose of this study is to derive solutions and prevent similar cases from occurring by analyzing the causes of cracks found in temperature cycling tests of rocket motor. Methods: By combining the results of the current state confirmation test, non-destructive test, domestic and foreign rocket motor comparison test, cutting test, and adhesion test according to the number of times to apply mold release agent, a Cause and Effect Diagram analysis was performed to derive the cause of cracks. Results: Through this study, 26 factors that could cause cracking in rocket motors during temperature cycling tests were identified. Through various additional test results, a total of five causes were identified, including chemical and structural design of the joint between the propellant and stress relief insert, omission of procedure in the manufacturing procedures, natural aging due to temperature, and load accumulation due to temperature changes. The fundamental cause was confirmed to be insufficient consideration of the release properties of the propellant and stress relief insert. Conclusion: During the design process, it was confirmed that this could be solved by structurally or chemically designing the insert so that it does not combine with the propellant, or by applying a mold release agent during the manufacturing process.

• Journal of Biomedical Engineering Research
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• v.33 no.4
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• pp.194-201
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• 2012

This study was designed to investigate the effect of a combined stimulus which was composed of chiropractic massage and thermotherapy on the relief of mental and physical stress. Fifteen healthy male subjects were treated with three type of stimuli; control (without any stimulus), a single stimulus (only chiropractic) and a combined stimulus. To evaluate the effects of stimuli, visual analogue scale (VAS), trunk extension, electromyogram (EMG) on erector spinae muscle and electrocardiogram (ECG) were measured and analyzed before and after stimuli. In the control group, there were no significant changes in EMG root mean square (RMS) value and low Frequency/high Frequency (LF/HF) ratio (p > 0.05, p > 0.05). However, both stimulus groups showed significant increases in trunk extension and EMG RMS values (p < 0.05, p < 0.05), but significant decreases in LF/HF ratios (p < 0.05). Particularly the decrement rate in LF/HF ratio was significantly higher in the combined stimulus group than that in the single stimulus group (p < 0.05). Also, a significantly lower VAS was recorded after combined stimulus. Our findings indicate that the combined stimulus might not only improve flexibility and strength of muscle, but also active parasympathetic nerve activity. The combined stimulus may thus contribute to relieve the stress and to enhance the muscle function.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.239-248
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• 2019

The purpose of this study was to examine the use of music for job stress of employees in highway service areas and differences in use of music. For this, a survey was conducted on 150 respondents of U city and G province. The questionnaires were composed of a total of 53 questions, including use of music 25, job stress 24, and demographic characteristics 4 questions. A total of 150 questionnaires were distributed and 134 were analyzed. As a result, first, the respondents preferred listening to music over playing instruments or singing and mostly listened to popular music at home alone. Second, they reported that their purpose of use of music was for mood change followed by comfort, joy, sense of vigor, and sense of relief. Third, there were significant differences in mood of music and degree of achieving sense of relief through music. This study could provide information for organizing effective convergence music programs which could meet the needs and demands of them.