• Journal of Korea Multimedia Society
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• v.13 no.12
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• pp.1814-1819
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• 2010

Since 1987, when statistical analyzing guide for thermal life test of Accelerated Life Test(ALT) was proposed as ANSI/IEEE Std 101, this guide has been used widely for many experiment data. Shim(2004) had done Monte Carlo simulation to compare life of two different systems or materials, based on statistic values obtained from ANSI/IEEE Std 101 data. In this study, a profile analysis is proposed for comparing life of two different systems or materials, and some examples using pre-existing data are given.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.3
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• pp.299-305
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• 2017

Gate-lifting devices in small- to mid-sized sluice gates mostly employ the mechanical roller rack pinion (RRP) system. This RRP system, which consists of a rack-bar and a pinion, transforms a rotation motion into a linear one. The rack-bar has a series of roller trains that mesh with the pinion. In this study, we adopt an exact involute-trochoid tooth profile of the pinion to obtain a higher contact fatigue strength using the profile modification coefficient. Further, we determine the contact forces and investigate Hertz contact stresses to predict the pitting life of the pinion according to varying the shape design parameters. The results indicate that the design fatigue life of an RRP system for sluice gate can be achieved only when the design value of the profile modification coefficient reaches or exceeds a certain level.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.95-101
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• 2012

An internal type roller ring gear(RRG) system composed of either a pin or a roller ring gear and its conjugated cam pinion can improve the gear endurance from that of a conventional gear system by reducing the sliding contact, while increasing the rolling motion. In this paper, we first proposed the exact cam gear profile and the self-intersection conditions obtained when the profile shift coefficient is introduced. Then, we investigated contact stresses and surface pitting life to fmd characteristics for surface fatigue by varying the shape design parameters. The results show that the pitting life can be extended significantly by increasing the profile shift coefficient.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.9
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• pp.1498-1506
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• 1997

Procedures are presented for influence of shot peening on fatigue strength, fatigue life and effects of shot peening are discussed from experiments were taken between shot peened and unpeened SPS5, SM45C specimens. After the residual stress on shot peened specimens was measured by X-ray diffractometer, rotating bending fatigue tests were carried out. In addition, the compressive residual stress profile was obtained by the superposition method of three stresses which is based on Al-Obaid's equation. Predicted fatigue life considering residual stress profile which was obtained by the Al-Obaid's equation and another predicted fatigue life considering residual stress profile which was measured in test were compared. For the purpose of predicting fatigue life, Morrow's equation considering the residual stress and mean stress was used.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.283-289
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• 2012

Cam rack pinion (CRP) system which consists of cam rack and roller pinion transforms the rotation motion into linear one. The roller pinion has the plurality of rollers and meshes with its conjugated cam rack. The exact tooth profile of the cam rack and the non-undercut condition to satisfy the required performance have been proposed by introducing the profile shift coefficient. The load stress factors are investigated by varying the shape design parameters to predict the gear surface fatigue limit which is strongly related to the gear noise and vibration at the contact patch. The results show that the pitting life can be extended significantly by increasing the profile shift coefficient.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.131-140
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• 2015

The purpose of this study is to predict the fatigue life of a planet carrier of a slewing reducer for a tower crane. To predict the fatigue life of the carrier, the inertia endurance test was carried out, and then the input torque profile for the reducer was obtained. The load profile acting on the planet pins that assembled the carrier was calculated from the measured input torque profile using commercial gearbox analysis software. The stress profiles of the carrier weak points were analyzed from the calculated load profile and boundary conditions using commercial FE software, and the stress cycles were determined using the rainflow counting method. Finally, the fatigue life of the carrier was predicted using the equivalent stress range by considering the effect of mean stress, and an S-N curve was drawn up using the GL guideline and the cumulative damage law.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.46.1-46.1
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• 2008

• Journal of Korean society of Dental Hygiene
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• v.11 no.6
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• pp.961-971
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• 2011

Objectives : The aim of the study was to identify the need of oral health education and prevention? for over 65 years elderly. Methods : his study was to identify the need of oral health management and oral health impact profile among elderly over 65 years. 200 elderly participated in the study, lived in KungBuk and KungNam areas, visited Senior welfare center, from 1st September to 30st December 2008. Results : 1. This majority of respondents are female(74.0%), 75-79 years(29.5%), none education(42.5%), living alone(45.5%), income from children(46.0%), and health insurance(65.5%). 2. In the need of oral health management category, the need of dental treatment are professional toothbrushing, gum treatment, treatment for dental caries, treatment for xerostomia. In the need of prevention and education, the majority participants are 'required'. In oral health impact profile category, the majority participants are 'feel no difficulty during speaking(59.0%)', and 'feel no difficulty during tasting(47.0%)'. In the category, the positive answers are more than negative answers. 3. According to general characteristic with the need of oral health management, famle, obviously income, high level of life are significantly different in the need of prevention and education category. Obviously income is significantly different in the need of dental treatment category. According to general characteristic with the oral health impact profile, getting older, high education are significantly different in disadvantage category. In the case of no spouse, anxiety, physical difficulty, mental difficulty and disadvantage are high score in oral health impact profile. In the case of living alone, pain, anxiety, and disadvantage are high score in oral health impact profile. In the case of no income, limitation of function, pain, anxiety, mental difficulty and disadvantage are high score in oral health impact profile. In the case of no health insurance, anxiety, physical difficulty mental difficulty and lack of sociality are high score in oral health impact profile. 4. The oral health impact profile are positive correlation with the need of dental treatment and the need of prevention education. The effect of oral health impact profile are significantly different with spouse, average of income, the need of prevention education. Conclusions : In Conclusion, the need of prevention education and dental treatment for individual oral health promotion are related with general life condition and life level. Also these are influence of quality of life relate with oral health. These findings are require of development of oral health services program and system from bottom to top.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.11
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• pp.1391-1397
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• 2012

A cam ring gear (CRG) system based on a hypotrochoid curve consists of a pinion with roller teeth and its conjugated internal CRG. In this study, we investigated contact forces, contact stresses, and load stress factors to predict the surface pitting life using an exact CRG profile by introducing the profile modification coefficient. The results show that the pitting life can be extended significantly by increasing the profile modification coefficient without any other change of parameters in the CRG system.

• Child Health Nursing Research
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• v.15 no.1
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• pp.61-70
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• 2009

Purpose: The purpose of this study was to identify the Health Promotion Life Profile of normal-weight and obese children, and factors related to obesity in elementary school children, and provide basic data for the development an obesity management program for these children. Method: The survey participants were 878 fourth to sixth grade elementary school children in Gwangju. $x^2$-test, t-test, ANOVA and multiple logistic regression with the SPSS program were used to analyze the collected data. Results: The Health Promotion Life Profile showed significant differences between normal-weight and obese groups according to food habits (t=3.305, p= .001) and exercise habits (t=-4.065, p=< .001). The Health Promotion Life Profile of obese children was also significantly different according to interest in weight control (F=3.044, p= .050), regular breakfast (F=3.699, p= .014), regular meals (F=6.868, p= .002). The multiple logistic regression analysis, showed that factors in obesity were significantly different according to gender, interest in weight control, fast eating, overeating and predilection for some food. Conclusion: The results of this study suggest that items on Health Promotion Life Profile such as food habits and exercise habits should be included in education programs to prevent obesity in elementary school children.