• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.189-192
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• 2006

This study was performed to suggest the mediocre prediction equation of chloride diffusion coefficient which is used to estimate the service life of marine concrete, in order to provide the useful data for concrete mix design of marine concrete. As a result, the mediocre prediction equation of chloride diffusion coefficient which set W/B and mineral admixture replacement ratio as parameters was presented by performing the multivariate non linear regression analysis.

• Journal of the Korean Wood Science and Technology
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• 제46권4호
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• pp.362-367
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• 2018

This study estimates the sound absorption capability of rice straw particle mats by two methods: the transfer function method and the reverberation room method. In the reverberation method, the central frequency was set to the one-third octave band in the 100-5000 Hz range; in the transfer function method, the frequency range was 500-6400 Hz. Both methods yielded similar noise reduction coefficients of the rice straw mats. The noise reduction coefficient was approximately 0.8, indicating a high sound-absorption property of the mats. Therefore, rice straw matting is a suitable candidate material for sound-barrier walls against highway noise.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제23회 춘계학술대회
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• pp.122-127
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• 1996

In this paper, the effects of the film tinckness, pre-treatment and testing load on. the tribological characteristics have been studied. During the "Ring on-Disk" testing period silica-gel was used to remove the effect of humidity. As a result, increasing the film thickness revealed prolonged wear life, in the case or reasl the testing loads the dynamic friction coefficient was decreased gradually but in regarding the wear life, an intermideate contact pressure (4kgf/mm${2}$) revealed the maximum value. In regarding the surface protuberance friction an intermediate value of area fraction (60%) revealed maximum wear life. In this paper, the qualitative model in regarding the variation of the friction coefficient andworn depth was presented.presented.

• 한국안전학회지
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• 제21권1호
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• pp.28-34
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• 2006

A procedure of estimating failure probability is demonstrated for a pressurized pipe of CrMo steel used at $538^{\circ}C$. Probabilistic fracture mechanics were employed considering variations of pressure loading, material properties and geometry. Probability density functions of major material variables were determined by statistical analyses of implemented data obtained by previous experiments. Distributions of the major variables were reflected in Monte Carlo simulation and failure probability as a function of operating time was determined. The creep crack growth life assessed by conventional deterministic approach was shown to be conservative compared with those obtained by probabilistic one. Sensitivity analysis for each input variable was also conducted to understand the most influencing variables to the residual life analysis. Internal pressure, creep crack growth coefficient and creep coefficient were more sensitive to failure probability than other variables.

• 한국농촌간호학회지
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• 제10권1호
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• pp.17-29
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• 2015

Purpose: This study was done to examine factors affecting quality of life among community-dwelling elderly women who live in rural areas. Methods: The design of this research was cross-sectional descriptive study. The participants were 92 community-dwelling women aged 65 or older. Data were collected from November 1 to 15, 2013. ADL (Kart's Index), GDS-SF (Geriatric Depression Scale Short Form) and GQOL (Geriatric Quality of Life Scale) were used to measure variables. Data were collected using self-administered questionnaires and analyzed using descriptive statistics, Spearman's coefficient and stepwise multiple regression. Results: The participants' mean age was 77.5, and 85.9% had elementary school graduation or less education, and for 64.1%, their economic status was low. Spearman's rho coefficient analysis found that QOL was significantly associated with depression (r=-.72, p<.001), perceived health (r=.58, p<.001), regular exercise (r=.47, p<.001), education level (r=.29, p=.005), and ADL (r=-.21, p=.043). Multiple regression analysis showed that 65.9% of their QOL was explained by depression (${\beta}=-.72$), perceived health (${\beta}=.24$), ADL (${\beta}=-.16$), exercise (${\beta}=.22$) and number of diseases (${\beta}=.19$). Conclusion: These results indicate that older women who live rural areas need support for ADL, and prevention of depression to improve their quality of life.

• 대한간호학회지
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• 제34권5호
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• pp.693-701
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• 2004

Purpose: The purpose of this study was to validate Quality of Life Index-Cancer (Q.L.I.-C) developed by Ferrans (1990) among Korean cancer patients. Method: This study design was exploratory factor analysis methodology. Q.L.I.-C was translated into Korean and reverse-translated into English. The subjects were 357 Korean patients with various cancers. Data were collected by questionnaires from May to August, 2000 and was analyzed by descriptive statistics, Principal Component Analysis for construct validity and Cronbach's alpha coefficient for reliability. Result: The range of factor loadings was .446～.841. The explained variance from the 5 extracted factors was 63.7% of the total variance. The first factor 'family' was 35.5%, and 'health & physical functioning', 'psychological', 'spiritual', and 'economic' factors were 11.5%, 6.9%, 5.6%, and 4.2% respectively. Because of cultural difference between Americans and Koreans, certain items such as sexuality, job status, and education were deleted from the extraction of factors in this study. The Cronbach's alpha coefficient was .9253 among the 28 items. Conclusion: Q.L.I.-C could be applied in measuring quality of life of Korean cancer patients. It also recommend to do further studiesfor validation of Q.L.I.-C American and Korean versions relating to cultural differences.

• 한국생산제조학회지
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• 제25권4호
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• pp.245-252
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• 2016

Girth gears are applied in the mining, cement, and mineral processing industries and used in various types of horizontal mills, rotary dryers and kilns, and other heavy-gear ring applications. The large ring gears are normally fitted outside mills or kilns to provide the primary rotational drive. Recently, an external pinwheel gear set (e-PGS) was introduced to overcome manufacturing problems associated with girth gears. e-PGS is also suitable for low-speed, heavy-duty mechanical transmission and dusty and poor-lubrication conditions. This paper first presents a new profile modification of root relief for the e-PGS cam pinion. We then investigate load-stress factors to estimate the surface fatigue life by varying the shape design parameters. The results show that the contact fatigue life of an e-PGS can be extended significantly by increasing the profile shift coefficient. However, support bearing life of the pinwheel depends more on the contact force distribution than the profile shift coefficient.

• 대한기계학회논문집A
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• 제36권4호
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• pp.387-393
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• 2012

본 논문에서는 기존 랙-피니언 시스템의 랙 치형을 핀 또는 롤러로 대체한 롤러 랙 피니언 (RRP) 시스템의 표면피로 향상방안을 고찰하였다. 우선 전위계수(profile shift coefficient)를 고려하여 RRP 시스템의 캠 피니언(cam pinion)에 대한 엄밀 치형설계 방법 및 언더컷 방지 조건을 소개하였고, 이를 바탕으로 설계인자의 변화에 따른 하중 및 하중응력계수(load stress factor)의 변화를 검토하였다. 이를 통해 RRP 시스템의 표면 내구성을 향상시킬 수 있는 방안으로 전위계수의 증가가 효과적임을 알 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제47권3호
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• pp.290-298
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• 2019

The sound absorption coefficient and transmission loss of several types of rice hull mats with varying apparent densities and thicknesses are estimated in this paper using the transfer function and matrix methods, respectively, to evaluate the possibility of using rice hull as an acoustic construction material. The mean sound absorption rates of 10-cm-thick rice hull mats with target densities of $0.10g/cm^3$, $0.12g/cm^3$, and $0.14g/cm^3$ were 0.91, 0.92, and 0.95, respectively, while those of the 1-cm-thick plywood attached to the back of the rice hulls were 0.90, 0.92, and 0.92, respectively. The means of the sound transmission loss of the 10 cm-thick rice hull mats with the target densities of $0.10g/cm^3$, $0.12g/cm^3$, and $0.14g/cm^3$ were 7.66 dB, 10.49 dB, and 14.14 dB, respectively, while those of the 1 cm-thick plywood attached to the back of the rice hulls were 33.34 dB, 36.72 dB, and 38.95 dB, respectively. In conclusion, a rice hull mat could be used as acoustic construction materials because of its high sound absorption coefficient and sound transmission loss.

• 한국인구학
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• 제8권2호
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• pp.46-67
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• 1985

In this paper, an attempt has been made to examine the pattern of mortality in Korea during 1970~80. By applying the age-sex specific mortality rates quoted from 1978~79 life tables for Korea published by NBOS, EPB to those of the West pattern of regional model life tables and the far eastern pattern of model life tables for developing countries, life expectancy at birth were calculated. Also the author reviewed the trends of death rates, life expectancy and cause of death using vital registration data and other materials. Summarized results are as follows; 1. Crude death rates in Korea was reduced to one fifth in the 1983 compared to that in 1920's. Life expectancy also improved to almost double in 1985 compared to 1920's. But the difference in the life expectancy between male and female increased during that period and it was recorded as 6.4 years in 1985. This discrepancy was mainly due to the different tempo of decreasing in mortality level by sex, particularly, for the age 40 and above. 2. For the pattern of mortality in Korea, it showed that female mortality could accounted closer to the West pattern model life tables. There were high similarity between actual pattern prevalent in Korea and West pattern. And its coefficient of variance was also very low. However for the case of male, it was difficult to find the exact model life tables for explaining the actual situation on the male mortality pattern which means exist considerable dissimilarity in older ages. The Far eastern pattern of U.N. model life tables show better results than West pattern, however, the deviation of the pattern to actual was severe. Also in Far eastern pattern, high coefficient of variance was existed. Furthermore it was found in the paper that the mortality level of Korean male for the age 40 and above were much higher than that of Far eastern pattern which was reflected the high mortality of the male adult in Far east region. 3. The analysis of cause of death showed that circulatory disease such as cerebrovascular disease and hypertensive disease accounted for the leading cause of death in Korea for the age 40 and above. There should he paid special attention to chronic retrogressive diseases for the older age groups. For younger age groups, injury and poisoning were reported as important cause of death.