• Composites Research
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• v.23 no.5
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• pp.22-29
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• 2010

This paper describes the evaluations of tension-compression fatigue characteristics and life for glass fiber/epoxy laminate composite applied to railway bogie to reduce weight. Test samples of tension-compression fatigue were composed of glass fiber/epoxy 4-harness woven laminate composites with different stacking sequence of warp-direction, fill-direction and ${\pm}45^{\circ}$-direction. The tension-compression fatigue test was conducted with stress ratio (R) of -1 and frequency of 5Hz. Goodman diagram were used to evaluate the fatigue characteristics and life of glass fiber/epoxy 4-harness satin woven laminate composite. Anti-buckling jig was designed to prevent buckling of specimen under compression load. The test results showed that the fatigue characteristics of glass fiber/epoxy 4-harness satin woven laminate composite with stacking sequence of warp-direction had a good performance in comparison with that of SM490 used to conventional metal railway bogie.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.762-765
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• 2007

A Giemsa C-banding method was used for the identification of somatic chromosomes and heterochromatic knob position in Korean indigenous waxy com (Zea mays L.). 5 inbred stocks were examined and their heterochromatic knob numbers ranged from 6 to 12. In comparison of homologous chromosomes of two stocks of YS-1 and MY-1, knob numbers, knob positions, arm ratios and relative length of chromosomes were different between the genotypes. The length of homologous chromosomes in YS-1 were generally larger than those of MY-1. The Giemsa method was proved to be useful for the identification of somatic chromosome and a C-banded diagram showing knob positions, arm ratios and relative length of chromosome could be used as a good tool to compare the characteristics of chromosomes of Korean indigenous waxy corn stocks.

• Science of Emotion and Sensibility
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• v.19 no.2
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• pp.67-78
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• 2016

The purpose of this study was to investigate relationships among the older drivers' subjective evaluation and objective performances for driving ability, mobility and subjective well-being. Scores for mobility and subjective well-being were obtained using questionnaires. Diagram-based driving scenarios and driving simulation were used to measure subjective and objective driving abilities, respectively. The results can be summarized as followings. First, subjective evaluation scores of driving ability but not objective driving performance significantly correlated with mobility. Second, the higher level of mobility predicted higher life satisfaction, higher positive affectivity, and lower negative affectivity. Third, the older driver's higher scores of subjective driving ability induced higher level of mobility, which, in turn, increased life satisfaction and positive affectivity but lower negative affectivity. The results suggested that subjective rather than objective ability for driving is more important in determining the level of old driver's subjective well-being.

• Journal of Korean Medicine Rehabilitation
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• v.31 no.1
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• pp.149-163
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• 2021

Objectives This study is to review the effectiveness of exercise after lung cancer surgery. Methods Relevant randomized controlled trials (RCTs) were searched in PubMed database. The systematic review was conducted through flow diagram. The risk of biases were assessed through the Cochrane guideline. Characteristics and outcomes were extracted from each study. Meta-analyses of forced expiratory volume in one second (FEV1), 6-minute walk test (6MWT), quality of life (QoL), pulmonary complications were conducted. Results 14 RCTs were selected. In meta-analysis, exercise improved FEV1 (mean difference [MD] 0.14; 95% confidence interval [CI] 0.04 to 0.25; p=0.009; I2=55%) and mean change of FEV1 (MD 0.11; 95% CI 0.02 to 0.20; p=0.02; I2=0%). Exercise increased the distance of 6MWT, but there was considerable heterogeneity (MD 45; 95% CI 21.16 to 68.83; p=0.0002, I2=89%). There was no differences in QoL scores by 2 questionnaires (European Organisation for Research and Treatment of Cancer quality of life questionnaire, short form-36). Exercise reduced the duration of hospital stay (MD -3.32; 95% CI -5.27 to -1.36; I2=0%; 2 studies) but not duration of chest tube intubation (MD -1.37; 95% CI -2.81 to 0.06; I2=0%) and incidence of pulmonary complications (pooled risk ratio 0.54; 95% CI 0.23 to 1.30; I2=0%). Conclusions Exercise might reduce the duration of hospital stay after lung surgery. There was not enough evidence to prove improvement of lung function, aerobic capacity, muscle strength, QoL, and decline of pulmonary complications. Low-quality risk of bias, different units or estimation of outcome, different exercise type and duration, heterogeneity among studies make the evidence of effectiveness weak. Future researches are required to redeem these defects.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.126-132
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• 2023

Recently, the consideration of eco-friendly technology to reduce greenhouse gas is being emphasized in the aviation field. Various studies for applying electro-mechanical actuators that control mechanical linear and rotational movements using electricity as the primary power source are in progress. In this study, the fatigue analysis of the electro-mechanical actuator for the front wheel steering of a single aisle aircraft was carried out. A unit load stress table was constructed for the vulnerable part selected through structural analysis, and the representative stress for each load profile was calculated using the unit load stress table constructed for the vulnerable part. Then, individual profiles of representative stress group were extracted from continuous load profiles by applying the rainflow counting method. The damage of each profile was calculated by applying the S-N diagram. Finally, the total damage in the vulnerable parts was calculated by the linear cumulative damage law, and the fatigue life of the electro-mechanical actuator for the front wheel steering of a single aisle aircraft was evaluated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.162-167
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• 2020

In this study, a fatigue analysis of an external fuel tank and pylon for fixed-wing aircraft was carried out as part of the domestic development of fixed-wing aircraft. Through structural analysis, the analysis areas were selected, and the transfer function for unit loads was established in the selected parts. For each of the continuous load profiles, stress components in the selected areas were calculated using the load of each profile and the transfer function, and the Von Mises equivalent stress was employed as the representative stress of each profile. In addition, the rainflow counting technique was used to extract individual profiles obtained from the initial large load profiles and to calculate their amplitude and average values. For life evaluation, the S-N diagram of the Metallic Materials Properties Development and Standardization (MMPDS) was applied, and the damage value was calculated by Miner's rule to assess the life of the selected area. As a result of the life assessment, the life span requirement for the selected area of the external fuel tank and the pylon was assessed as being satisfied.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.913-920
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• 2011

We describe the evaluation of the fatigue life and strength of a lightweight railway bogie frame made of glass fiber/epoxy 4-harness satin-woven composites. To obtain the S-N curve for the evaluation of the fatigue characteristics of the composite bogie frame, we performed a tension-compression fatigue test for composite specimens with different stacking sequences of the warp direction, fill direction, and $0^{\circ}/90^^{\circ}$ direction. We used a stress ratio (R) of -1, a frequency of 5 Hz, and an endurance limit of $10^7$. The fatigue strength of the composite bogie frame was evaluated by a Goodman diagram according to JIS E 4207. The results show that the fatigue life and strength of the lightweight composite bogie satisfy the requirements of JIS E 4207. Given its weight, its performance was better than that of a conventional metal bogie frame based on an SM490A steel material.

• (The)Study of the Eastern Classic
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• no.33
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• pp.57-96
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• 2008

Kim, Kyung Jang(1597~1653) as a disciple of Jang Hyun Gwang was very famous for his virtuous conduct. But his collection of works has been published recently. There has never been any studies about his thoughts, learning and life. Therefore this study has a target to arrange the process of his life and events, and to introduce outlines of his learning. The items of this study will be as follows: The first category will be his lineage, his life, and writings. The second category will be his learning. This category has two lower categories. The first will be focused on his intention to morally accomplished self by the method of self cultivation and practise of Confucian proprieties. The second will be focused on his learning of the Change and of the Confucian proprieties. And giving attention to his 6 diagrams that have symbolized principles of the Change, this paper tries to compare these to the other scholars ones and so will explane the features of his diagrams. The most important thing in this paper is to define his learning as so called in the rhetoric of Confucianism Wi-gi-ji-hak(爲己之學), which means self organization of one's moral personality by the method of self cultivation and to distinguish the steps of his learning developed. This method has never been applied, but this is expected to become a effective method for explanation of the truth of the Confucian scholar's world of learning.

• Journal of Korea Technology Innovation Society
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• v.17 no.4
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• pp.733-762
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• 2014

The government mandates that national research facilities & equipments through R&D business budget should be registered on the National Science and Technology Information Service (NTIS) for the purpose of the efficient use of the research facilities & equipments. This study is to contribute to the national policies on the efficient management of the research facilities & equipments by recognition methodology with the university's members and analysis of the impact factors of the universities' registration process improvement through the Define level and Measure level of the Six Sigma DAMIC. The survey and interview were conducted on research directors, professors joining university administration, graduate students, researchers, and staffs of A University. The findings are the lack of understanding specific steps and life-cycle management of research facilities & equipments. It is necessary to collect suggestions from universities and pursue policies considered the unique characteristics of the university for advanced operating and maximizing use of university's national research facilities & equipments. Research facilities & equipments enrollment compliance rate and registration accuracy were selected as CTQ-Y through the Six Sigma. 72 potential cause variables were derived through Process Map and C & E Diagram. 13 variables were determined as core potential factors through the X-Y Matrix and Pareto Chart. Research institutions should maximize utilization of research facilities & equipments through deriving a potential variables of the process improvements and designing a detail improvements based on the characteristics of each institutions.

• Journal of Korean Society of Forest Science
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• v.106 no.4
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• pp.457-464
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• 2017

This study has utilized the stand density management diagram to devise an efficient management standard for the stand density for Pinus densiflora that secures the health of the stands and predicted the harvest goals. The appropriate stand control level was estimated by modeling the relationship of the relative yield index (Ry) to the ratio of slender trees within the stand through an exponential function; the coefficient of determination ($R^2$) was found to be 0.424 according to the estimation. The ratio of slender trees within the stand showed a tendency of rapid increase at a certain relative yield index; with this relational function, the appropriate Ry value of 0.84 was obtained. By estimating the curve of the Ry value 0.84, which was the appropriate stand density management level, as well as the height of dominant trees in the central region of Korea, the production objective for each site index was set. Assuming that the final age by the site indices ranged from 10 to 16 for the P. densiflora in central region of Korea, the number of production was estimated to be between 426 to 1,311 trees per ha. It was predicted that the production of medium-diameter logs larger than 30 cm in diameter is possible for the target DBH at a site index of more than 16; small-diameter logs larger than 20 cm in diameter for site indices 12 and 14 enabled, and small-diameter logs of less than 20 cm for site index 10.