• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1453-1458
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• 2008

For quantitative PCR assay of Salmonella enterica serovar Typhimurium in food samples, a real-time PCR method was developed, based on DNA genome equivalent. Specific primers and probe designed based on the STM4497 gene of S. Typhimurium LT2 showed the specificity to S. Typhimurium. Threshold cycle (Ct) values of real-time PCR were obtained from a quantitative standard curve with genomic DNA of Salmonella Typhimurium. In addition, the recovery of S. Typhimurium inoculated artificially to chicken samples with $4.5{\times}10^5$ to 4.5 CFU/ml was evaluated by using real-time PCR and plate-count methods. Result showed that the number of cells calculated from the real-time PCR method had good correlation with that of the plate-count method. This real-time PCR method could be applicable to the detection and quantification of S. Typhimurium in food samples.

• Journal of the Korean Regional Science Association
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• v.35 no.2
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• pp.59-71
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• 2019

Korea's average annual working hours are among the highest in the OECD. Such long-term work has been a factor that reduces the quality of life by discouraging workers' productivity and interrupting the compatibility of work and family, prompting the government to encourage flexible work systems, such as increasing part-time jobs, but a lack of quality part-time jobs. Part-time work enables flexible labor for workers, but at the same time, workers will involuntarily opt for part-time work as they have poor working conditions and negative social views. In this respect, the effect of the working type on an individual's life is expected to be different. In addition, for women, gender gaps exist in the labor market and the impact of part-time work on life satisfaction is expected to differ from men in terms of working and family alike. Using the data from the 2017 "Seoul Survey Urban Policy Indicator Survey", the ordered logistic regression model was used to analyze the cross-effect of working type and sex on satisfaction. The analysis of the study showed that when other factors were controlled, life satisfaction was high in the order of fulltime female, full-time male, part-time female, and part-time male. In addition, further analysis shows that the parttime female workers have the highest probability of choosing low life satisfaction, while the probability of choosing high life satisfaction is the lowest, and full-time male workers have the lowest probability of choosing low life satisfaction, while the highest probability of choosing high life satisfaction is the highest.

• Journal of the Korean Home Economics Association
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• v.32 no.3
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• pp.11-26
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• 1994

The purpose of this study is to investigate the change of time use in employed husbands and their wives according to family life cycle. Data for 284 couples were gathered from the structured questionnaire and time diary. The major findings of this study were as follows; (1) The family life cycle had effected on the time use of wives changed remarkable. That is to say the housework time of the unemployed wives decreased after increasing to the second stage but the social-cultural time of those changed to the contrary. (2) The family life cycle affected only the husbands' housework time on the weekend but wasn't the important effect of time use in case of the employed husbands.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.05a
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• pp.171-176
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• 1999

Nondestructive inspection and accompanying life analysis based on fracture mechanics were the major conventional methods for evaluating remaining life of critical high temperature components in power plants. By using these conventional methods, it has been difficult to perform in-service inspection for life prediction. Also, quantitative damage evaluation due to unexpected abrupt changes in operating temperature was almost impossible. Thus, many efforts have been made for evaluating remaining life during operation of the plants and predicting real-time life usage values based on the shape of structures, operating history, and material properties. In this study, a core software for on-line life monitoring system which carries out real-time life evaluation of a critical component in power boiler(high temperature steam headers) is developed. The software is capable of evaluating creep and fatigue life usage from the real-time stress data calculated by using temperature/stress transfer Green functions derived for the specific headers and by counting transient cycles. The major benefits of the developed software lie in determining future operating schedule, inspection interval, and replacement plan by monitoring real-time life usage based on prior operating history.

• The Journal of Korean society of community based occupational therapy
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• v.9 no.3
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• pp.31-39
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• 2019

Objective : The purpose of this study is to identify time management among college students and provide them with a basic resource for planning and educating them on efficient time management methods for improving the quality of life of all clients who receive occupational therapy services, including non-disabled people. Methods : This study is a survey of four-year university students using the questionnaire to know the relationship between structured time usage and quality of life. A total of 142 questions, excluding eight missing questionnaires, was compared and analyzed with using the general characteristics, time structure questionnaires (time structure questionnaires) and World Health Organization (WHOQOL-BREF). Results : The results of this study showed that there was a significant correlation between quality of life and structured time management, and between the sub-items of structured time management; sense of purpose, structured daily life, persistence, past direction and sleep intensity. Also, factors that affect the quality of life were sleep (β=.214), structured daily life (β=.203), a sense of purpose(β=.343), and past direction(β=.244) appeared in order. Conclusion : In the case of university student who is working within structured time, there were difficulties in showing satisfactory quality of life. These factors of poor quality of life were analyzed to affect structured daily life, sense of purpose, past direction, and sleep level.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.3
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• pp.516-522
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• 2009

The dimmable magnetic ballast which applies the variable inductor needs a switching process for the dimming process, and it consists of mechanical relays because of costs and reliabilities. However, it is hard to operate with correct timing in mechanical relay, so relays reduce their own life time in inductive applications. Moreover this creates a destructive problem at the switching process. The life time reduction of relays means the life time reduction of the ballast. Thus, in this paper, we described the problem at the witching process in the dimmable magnetic ballast with a variable inductor, which consists of relays and the soft AC switching method in order to solve the problems. As result, we achieved the improvement of the life time and reliability of the ballast.

• Journal of the Korea Institute of Military Science and Technology
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• v.3 no.1
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• pp.26-37
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• 2000

This research paper deals with the problem of determining the optimal life time in terms of economical sense for a self-propelled artillery. Equivalent Annual Cost Method(EACM) is used to evaluate the optimal life time, based on the acquisition cost, and the operation and maintenance cost. It is assumed that the operation and maintenance cost includes the costs for spare parts, petroleum and ammunition for training. From the result of this study, the optimal life time for a self-propelled artillery is between 13.9 years and 16.1 years with 95% confidence interval.

• Journal of KSNVE
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• v.10 no.4
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• pp.686-691
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• 2000

In this paper a computer aided analysis method is proposed for durability assessment in the early design stages using dynamic analysis, stress analysis and fatigue life prediction method. From dynamic analysis of a vehicle suspension system, dynamic load time histories of a suspension component are calculated. From the dynamic load time histories and the stress of the suspension component, a dynamic stress time history at the critical location is produced using the superposition principle. Using linear damage law and cycle counting method, fatigue life cycle is calculated. The predicted fatigue life cycle is verified by experimental durability tests.

• Journal of Ocean Engineering and Technology
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• v.10 no.1
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• pp.47-52
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• 1996

This paper deals with a study on improvement of long-time creep life prediction of steam turbine rotor steels by using initial strain method as a new approach at high temperatures of 500 to 70$0^{\circ}C$ . The main result shows that the inital strain method could be reliably utilized to predict and evaluate the long-time creep life as creep rupture strength and that the predicting equation for long-time creep life under a certain creep stress at a certain high temperature could be empirically derived out from each initial instantaneous strain measured.

• Korean Journal of Human Ecology
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• v.7 no.4
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• pp.83-98
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• 2004

The purpose of this study is to provide basic information necessary for improving the satisfaction and quality of leisure life and thereon propose better leisure life programs in accordance with gender. For the purpose, this researcher made a questionnaire survey of 560 persons between July and December 2003 to know the trend and satisfaction of their leisure life in accordance with their gender. Results of the study can be summarized as below; First. the extent to which the surveyed persons participated in leisure life was highest in terms of other leisure activities, followed by self-development. viewing activities, sports activities and journey in order. The satisfaction of leisure life participation by those surveyed persons was scored 3 or over in average, meaning 'generally satisfied'. The time of leisure life participation was most spent in other leisure activities and self-development. Expenses of the participation were highest in terms of other leisure activities. followed by self-development and viewing activities in order. Second, differences in sub-areas of leisure life were analyzed in accordance with gender to show that the degree and time of participation in viewing activities and self-development, expenses of sports activity participation and the degree of participation in journey and others were significantly different between the opposite sexes which were surveyed here. Men were higher in the degree, time and expenses of the participation than women. Third. effects of gender on the satisfaction of leisure life as a whole were determined here to show that men were higher in such satisfaction when they were more satisfactorily participating in sport activities while in case of women, when they were spending more time in sport activities. Women showed a higher satisfaction of leisure life as a whole when they were more frequently and satisfactorily participating in other leisure activities. Based on these results, the researcher proposed effective leisure life programs in accordance with gender.