• Journal of Biosystems Engineering
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• 제28권6호
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• pp.537-544
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• 2003

The objectives of this study were to investigate the failure characteristics of a total of 90 parts of tractor driveline, and to predict their average annual demands required to perform the after-sales service. The failure characteristics such as failure mode, mean time between failures, characteristic life and reliability were analyzed using the data collected through the experienced mechanics at the part centers of the tractor manufacturers. The analysis was based on the assumption that the failure distribution follows the Weibull distribution. The average annual demands were also predicted for the replacement parts using the mean time between failures and the renewal theory based on the Weibull distribution. The results of the study revealed that the driveline parts failure was mostly from wearout and their average characteristic life is about 1.760 hours. The estimated mean time between failures was in a range of 670∼3,740 hours and reliability in a range of 40∼60％. The annual replacement demands were in a range of 4∼45 for a service of 100 tractors.

• Asian-Australasian Journal of Animal Sciences
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• 제15권9호
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• pp.1232-1236
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• 2002

Direct and service sire genetic parameters for total number of pigs born (TNB), number of pigs born alive (NBA), total pig weight at birth (TWB), and average pig birth weight (ABW) were estimated by DF-REML under a multiple trait animal model. Data on 3,078 litters of the Yorkshire from Jan, 1975 to Dec, 1998 at National Livestock Research Institute were obtained. The animal model included fixed contemporary group effects and random additive direct, service sire, and residual effects. Additive genetic relationships among animals were included. A separate relationship matrix for service sires and their sire was also included. Additive direct heritability estimates for TNB, NBA, TWB, and ABW were 0.19, 0.18, 0.25 and 0.39, respectively. Service sire heritability estimates for TNB, NBA, TWB, and ABW were 0.02, 0.01, 0.02 and 0.01, respectively. The genetic and phenotypic correlations of TNB with NBA estimated in this study were 0.81 and 0.81, respectively, and the genetic and phenotypic correlations of TNB with TWB estimated were 0.82 and 0.76, respectively. Results indicate that service sires account for 1 to 2% of the total variation for TNB, NBA, TWB, and ABW. Further investigation is needed to determine whether the service sire effect is primarily genetic or environmental.

• 한국구조물진단유지관리공학회 논문집
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• 제19권2호
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• pp.68-75
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• 2015

본 연구에서는 고속도로 교량 바닥판 747개소의 GPR 데이터를 분석하여 주요 열화인자를 도출하고, 이들을 활용하여 교량의 공용연수에 따른 교량의 손상률을 추정하였다. 바닥판의 손상률 데이터를 공용연수에 따른 영향을 최소화하기 위해 공용연수에 따른 손상률 데이터를 선형회귀분석 모형을 사용하여 보정하였다. 보정된 바닥판 손상률과 강설일수, 강설량, 동결융해일수, 동절기평균기온, 고도, 제설제살포량, 환상교통량의 상관관계를 분석하였으며, 동결융해일수와 제설제살포량이 바닥판의 손상률에 지배적인 영향이 있음을 도출하였다. 동결융해일수와 제설제살포량을 동시에 고려하여 복합열화 상황 하에서 바닥판의 손상률 차트를 도출하고, 이를 기반으로 평균적인 예상 바닥판 수명을 도출하였다. 본 연구의 결과는 고속도로 교량의 유지관리 시에 현 교량상황별로 바닥판의 열화진전 상태와 전단면 개량이 필요한 시점을 예상할 수 있는 참고자료로 활용될 수 있을 것이다.

• Journal of Hospice and Palliative Care
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• 제8권2호
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• pp.234-244
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• 2005

As Korea has just turned into an aging society with the increase of average life expectancy, and the main causes of deaths is cancer and other chronic diseases. And this corresponds to a dramatic increase in medical expenses for the aged. To curve this problem, the hospice care can be an effective alternative, which can provide patients with both quality service and intensive care to help ensure high quality life for the patients. To demonstrate the economical effect of hospice services, a comparative study on the media expenses of geriatric hospitals and general hospitals, which bear similarities in common regarding the characteristics of their patients, is performed. Thus the results of the study can serve as a quantitative indication for the management of hospice services.

• Asian-Australasian Journal of Animal Sciences
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• 제18권2호
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• pp.179-184
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• 2005

First lactation records (174) of Jersey${\times}$Sahiwal and Holstein Friesian${\times}$Sahiwal half breds under 9 sires maintained at Chandra Shekher Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh, India from 1975-1983, were used to estimate the genetic parameters and to predict herd life milk yield and average milk yield per day of herd life from first lactation traits. The traits included were: age at first calving, first service period, first lactation period, first calving interval, first lactation milk yield, milk yield per day of first calving interval, herd life milk yield, herd life and average milk yield per day of herd life. Most of the production and reproduction traits were found to have positive and significant correlations between them on genetic as well as phenotypic scales. Total twelve regression equations were fitted. The prediction equation of herd life milk yield in both the genetic groups showed linear relationship with AFC, FSP, FLP, FLMY and MY/DCI and was apparent and significant. Similarly, polynomials for milk yield per day of herd life for J${\times}$S and HF${\times}$S half breds also showed linear trend, which was found highly significant. The highest and lowest $R^2$ values were found for FCI and AFC, respectively.

• 대한영양사협회학술지
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• 제18권1호
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• pp.1-15
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• 2012

The purpose of this study was to provide fundamental data for health promotion and improvement of the dietary life in students who receive school lunch support (SLS) by comparative analysis of food service satisfaction, dietary habits, and nutrition intakes according to SLS. The subjects of this study consisted of 258 boys and 233 girls at a middle school in Incheon. The students' average age was 14.9 years, average height was 161.3 cm, and average weight was 52.0 kg. The breakfast eating frequency of the No-SLS (NSLS) group was significantly greater than that of the SLS group (P<0.05). The time spent for eating breakfast in the SLS group was significantly shorter than that of the NSLS group for boys. There was no significant difference in dietary attitudes according to SLS. For satisfaction of the quantity and diversity of the school lunch menu in girls, the SLS group had higher satisfaction than the NSLS group. The daily energy intake of the SLS group was significantly lower than that of the NSLS group in both boys and girls. The majority of daily nutrients intakes in the SLS group were also significantly lower than those in the NSLS group. In summary, the female students in the SLS group were more satisfied with school lunch service than general students. However, SLS students less frequently ate breakfast and showed lower energy and nutrient intakes. Therefore, in order to improve the nutritional status and dietary life of students who receive school lunch support, consistent nutrition management and support in schools are required.

• 산업경영시스템학회지
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• 제34권1호
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• pp.74-79
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• 2011

Engineering valuation is a specialized discipline requiring expert knowledge and judgment, which scientifically estimates the economic value of industrial properties. By industrial properties, we mean engineering structures such as mines, factories, buildings, machines, and other industrial facilities as well as facilities of public enterprises. Particular industrial properties can have longer economic life if their performance is excellent and they are still suitable for current manufacturing needs. If not, its economic life will be shorter. As speed of technological progress becomes rapid, life-cycle and development period of a product is becoming shorter. In an industry characterized by rapid development of technology, industrial properties can become obsolescent faster. Even if they are in good working order, they could be no longer suitable for manufacturing new products based on radically different technology. In our research, we apply engineering approach to estimating functional economic life by factoring in technological obsolescence in such an industry.

• 한국치위생학회지
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• 제21권3호
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• pp.311-318
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• 2021

Objectives: The purpose of this study was to understand the level and patterns of college adjustment, major satisfaction, academic engagement, and attention deficit hyperactivity disorder (ADHD). This study examined the factors influencing adaptation to college life. Methods: This study was approved by the institutional review board of 00 university. We analyzed 166 survey data responses collected by distributing questionnaires from June 1 to July 2, 2020. Statistical product and service solutions version 23.0 was used for statistical analyses. The data were presented as frequencies and percentages or means and standard deviations, and pearson correlation analysis and multiple regression analysis were performed. Results: There was a significant difference in the average score of major satisfaction according to the type of college (university) and grades. For college adjustment, there was a significant difference in the average score according to major grades. Academic engagement showed a significant difference in the average score according to the college type and grade. Major satisfaction, college adjustment, and academic motivation showed significant positive correlations among the variables, whereas ADHD, major satisfaction, and college adjustment showed a significant negative correlation. Multiple regression analysis revealed that major satisfaction (p<0.001) and academic motivation (p<0.001) were factors affecting college adjustment (p<0.05). Conclusions: It is necessary to develop and apply specific and systematic adaptation programs to improve the understanding, control, and guidance methods for college students and to promote human relations, such as school life and social life.

• 한국구조물진단유지관리공학회 논문집
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• 제23권2호
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• pp.10-19
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• 2019

염해에 콘크리트 구조물은 사용기간의 증가에 따라 내구성에 문제가 발생하므로 보수를 포함한 유지관리가 필수적이다. 일반적으로 결정론적인 방법으로 내구수명이 결정되고 이에 따라 유지관리비가 평가되고 있으나, 확률론적 유지관리 기법을 고려할 경우 연속적인 보수비용이 평가되므로 합리적인 유지관리가 가능하다. 기존의 확률론적 유지관리 기법에서는 정규분포만 고려되었으나, 본 연구에서는 초기 내구수명 및 보수에 따른 수명-확률함수에 로그함수를 고려할 수 있도록 개선되었으며, OPC 및 GGBFS를 사용한 콘크리트에 대하여 보수비용을 평가하였다. 로그 함수를 가지는 수명-확률함수는 중앙값 이전보다 이후에 미치는 영향이 지배적이므로 초기 내구수명 분포에 유리하며 전반적으로 낮은 보수비용을 도출할 수 있다. GGBFS를 사용한 콘크리트는 OPC 콘크리트 비하여 높은 내구수명과 낮은 보수횟수를 통하여 30% 수준으로 보수비가 감소하였다. 본 연구에서 도출된 확률론적 유지관기 기법은 정규분포 뿐 아니라 로그분포를 가지는 수명-확률함수를 초기 및 다양한 보수시기에 적용할 수 있는 장점을 가지고 있으며, 더욱 합리적인 보수비용을 도출할 수 있다.

• 가족자원경영과 정책
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• 제19권3호
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• pp.81-99
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• 2015

This study investigates the balance between work and family, and the happiness of married working women who have preschool-aged children. Data were collected from 321 questionnaires that consisted of three parts: 1) basic demographic variables, 2) family-life variables, and 3) working-life variables. SPSS 21.0 was used for the statistical analysis. The variables that were identified to have a statistically significant impact on the balance between work and family were income, age of first child, time spent on housework and childcare on weekdays, time spent on housework on weekends, family-friendly service in the workplace and flexibility of work schedule. 2) The variables that were identified to have a statistically significant impact on happiness were age, income, time spent on housework on weekends, satisfaction with spouse's participation in housework and childcare, average working time, family-fiendly service in the workplace, flexibility of work schedule, and balance between work and family. The majority of the variables that influence balance between work and family, and happiness related to aspects of work, such as family-fiendly service, flexibility of work schedules, and average working time. The results also found that the load of housework and childcare on weekends is a heavy burden for working women. Further research needs to focus on developing the extending index of happiness including the measure of balance between work and life. In addition, further studies with more varied groups need to be conducted.