• Proceedings of the KSME Conference
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• 2000.04a
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• pp.280-285
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• 2000

A viscoelastic constitutive equation of rubber that is under small oscillatory load superimposed on large static deformation is proposed. The proposed model is derived through linearization of Simo's viscoelastic constitutive model and reference configuration transformation. The proposed constitutive equation is extended to a generalized viscoelastic constitutive equation that includes widely used Mormin's model as a special case using objective stress increment. Static deformation correction factor is introduced to consider the influence of Pre-strain on the relaxation function. The proposed constitutive model is tested fer dynamic behavior of rubber specimens with different carbon black contents. It is concluded from the test that the viscoelastic constitutive equation for filled rubber must include the influence of the static deformation on the time effects. The suggested constitutive equation with static deformation correction factor shows good agreement with test values.

• Science of Emotion and Sensibility
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• v.14 no.1
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• pp.59-72
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• 2011

Since stress can cause a variety of diseases, the relaxation of stress is an important factor for preventing diseases. One way to relieve stress is to use auditory or visual materials. If auditory and visual ones are used together, the effect of stress relaxation will be maximized. In this context, we analyze mood distribution of genre of music and color distribution of mood from the mood data for musics and color data for mood words collected directly from volunteers. Based on these two distributions, we also perform the $X^2$-test with Minitab for checking that color distributions are different from genre to genre. The results show that a different genre has a different color distribution and that the distributions of color, brightness and saturation depend on mood (P<0.0001). The results will be used to develop an emotional lighting system which plays lighting according to music mood, which can be applied to psychotherapy but more data and analysis are needed for clinical trials.

• Korean Journal of Health Education and Promotion
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• v.18 no.3
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• pp.117-131
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• 2001

This study was attempted to develope a highly reliable and valid tool which is useful to assess the Korean obese adolescents' stress and coping method. The data were collected from the total of 600 obese students from middle and high schools in Pusan. The author used a convenience sampling method. The data collection was done from March 2 to July 11, 1999. The analysis of the data was done with SPSS Win(10.0) for descriptive statistics and factor analysis. The preliminary tool was composed of 72 items(stress items: 34, coping method items: 38) with the five point Likert scale. Item analysis and inter consistency were calculated for reliability and validity through pre-test. The preliminary tool was analyzed for reliability and validity. Finally, the tool was of 65 items(stress items: 33, coping method items: 32). The results were as follows: 1. Cronbach Coefficient Alpha for the 33 items of stress was .9485 and the 32 items of coping method was .8534. 2. The factor analysis was done in order to confirm construction and the items were extracted Oblimin rotation and Maximum likelihood extraction method. 3. The factor analysis showed 6 factors in stress and 10 factors in coping method. These 6 factors of stress explained 62.4％ and 10 factors of coping method explained 57.4％. 4. Six factor of stress lable were 〈outward appearance〉, 〈boyfriend/ girlfriend〉, 〈occur an outbreak of disease〉, 〈mutual relation of family〉, 〈an obese figure〉, 〈be a burden on exercise〉. 5. Ten factor of coping method lable were 〈be concerned about another affairs〉, 〈recreation activities〉, 〈self-violence〉, 〈relaxation〉, 〈hobby activities〉, 〈avoid a situation〉, 〈communication〉, 〈music〉, 〈negative behavior〉, 〈positive thinking〉. The results of using this scale in a study will contribute to design an appropriate school health management of obese students, and also it will contribute to the development of nursing research.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.341-344
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• 2008

Plastics is commonly used in consumer electronics because of it is high strength per unit mass and good productivity. But. using, transporting, and keeping of plastic component was happened post-deformation. As time goes by and temperature is changed, the post-deformation causes the problems of exterior design and performance. But, it is difficult to estimate the post-deformation by only thermal deformation analysis. Also, the estimation technique of the pest-deformation must be easily applied to product development and it should be reliable because development time of product is limited. In the paper. the process to predict the post deformation under cyclic thermal loadings was suggested. The process was applied to the real panel, and the deformation predicted by the analysis was compared with that of real test, which showed the possibility of applying the suggested process to predict the post deformation of plastic product under thermal loadings.

• Journal of Korean Academy of Nursing
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• v.37 no.4
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• pp.529-539
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• 2007

Purpose: This quantitative meta analysis sought to determine the effectiveness of SMIs. Method: Forty-six experimental studies with a randomized or nonequivalent control group pre-post test design were included in the analysis. The selected studies were classified according to the sample characteristics, the types and methods of the interventions, and the types of outcome variables. Six intervention types were distinguished: cognitive-behavioral intervention(CBT), relaxation techniques(RT), exercise(EX), multimodal programs 1 and 2(MT1, 2), and organization-focused interventions(OTs). Effect sizes were calculated for the 4 outcome categories across intervention types: psycho-social outcome, behavioral-personal resources, physiologic, and organizational outcome. Results : Individual worker-focused interventions(ITs) were more effective than OTs. A small but significant overall effect was found A moderate effect was found for RT, and small effects were found for other ITs, The effect size for OTs was the smallest. The interventions involving CBT and RT appeared to be the preferred means of reducing worker's psycho-social and organizational outcomes. With regard to physiologic outcomes, RT appeared to be most effective. CBT appeared to be most effective in reducing psycho-social outcomes. The effects of OT were non-significant, except for the psycho-social outcomes. Conclusions: SMIs are effective. Interventions involving RT and CBT are more effective than other types.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.167-174
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• 2003

Fatigue damage of 2.2Ni-1Cr-0.5Mo steel used fir high strength pressure tubes and vessels was evaluated using uniaxial specimens subjected to strain-controlled fatigue loading. Based on the fatigue test results from different strain ratios of -2. -i 0, 0.5, 0.75, the fatigue damage of the steel was represented by using a cyclic strain energy density. Mean stress relaxation depended on the magnitude of the applied strain amplitude. The high pressure vessel steel exhibited the cyclic softening behavior. Total strain energy density consisting of the plastic strain energy density and the elastic tensile strain energy density described fairly well the fatigue life of the steel, taking the mean stress effects into account. Compared to other fatigue damage parameters, fatigue life prediction by the cyclic strain energy density showed a good correlation with the experimental fatigue lift within a factor of 3.

• Journal of Korean Association for Spatial Structures
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• v.14 no.3
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• pp.85-92
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• 2014

Most of the structural forms in which ETFE film is used are the cushion(pneumatic membrane structures) and tension type(tensile membrane structures), which have been generally accepted to be the most efficient forms. Tensile membrane structures are pulled outward from the exterior to introduce initial stress. And such structures offer the advantage of a natural shape formed by tensile stress and eliminate the need for blast air. Recently, the number of tension type structures is increasing. However, there are problems of creep and relaxation of ETFE films under long-term stresses. In this paper, the stretch fabrication method is proposed for stretching the film into the plastic region during initial tensioning as a way to increase its strength. And its effectiveness is confirmed by investigating experimental and analytical test using ETFE films.

• Korean Journal of Food Science and Technology
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• v.18 no.3
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• pp.215-220
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• 1986

Mechanical properties of 9-30% starch gels from naked and covered barley were investigated with rheometer or rotation viscosimeter. The compression-penetration curves of 20 and 30% gels were characterized by deformations containing elastic, plastic and fracture regions under the load of 0-2kg. The compressive stress relaxation test showed that the viscoelastic properties of 20% gels may be represented by four element Maxwell model consisting of two Maxwell element in parallel. Also, stress-decay under the steady shear of 9% covered starch gel was able to be interpreted by linear viscoelastic model and stress-decay process was suggested to be effective to investigate the effect of temperature or additives on gel structure.

• Research in Community and Public Health Nursing
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• v.13 no.1
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• pp.17-29
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• 2002

This study was carried out to investigate the effect of Self-foot reflexology (SFR) on the hypertension of workers. The purpose of the research was to evaluate: levels of knowledge, physical and emotional condition, work stress and fatigue on the hypertension of employees in the workplace. Quasi-experimental study was designed in the setting of a nonequivalent control and experimental Group applied by the pre and post test. The total subjects undertaken in the study were total of 34 employees working in three companies in Seoul. The SFR program was consisted of 6 phases. There were 2 minutes for preparation, 4 minutes for slow down, 26 minutes for base reflex, symptoms of a disease reflex and excretion reflex stimulation. Finally, there was 20 minutes relaxation in a comfortable posture and drinking hot water after blood pressure was checked in the order. This program was running 55 minutes a day everyday three times a week during the entire 8 week course. The finding showed blood pressure was reduced significantly. Moreover, the level of total cholesterol. high and low density lipoprotein cholesterol, depression, work stress, and fatigue were decreased in the study. But, they were not statistically significant except as it related to Group comparisons in time. The level of state anxiety was statistically significant between 2 Groups, but not in the time comparison of both Groups. As a summary of the study results, the SFR program was regarded as contributing to the physical and emotional promotion of employees. It had partially increased body circulations of functional organ related to the SFR sites. And, it improved relaxation of physical and mental condition through energy movement 'Chi'. Therefore, the SFR technique should be considered as an effective skill of a nursing program. Furthermore, it can be newly adopted as a nursing curriculum as a part of alternative treatment. However, it still needed to testify its effects through the review study.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.57-62
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• 2013

A crack in a solid propellant increases the area of burning surface, which leads to excessive burning that causes motor failure. Therefore, it is necessary to evaluate fracture toughness of solid propellants. However, it is very difficult to measure fracture toughness of solid propellants because of the nonlinear mechanical behavior. In this study, evaluation of fracture toughness on a solid propellant was carried out under the assumption that the solid propellant is a linear viscoelastic material. Actual displacements from fracture toughness tests using CCT specimens were converted into pseudo-elastic displacements by using stress relaxation characteristics and fracture toughness was evaluated using ASTM E399 standard. Also, effects of test temperature and speed on the fracture toughness were considered.