• The Korean Journal of Food And Nutrition
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• v.31 no.2
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• pp.284-292
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• 2018

This study was conducted to determine the elements that are required and that need improvement in the contents of dietary life education and the educational environment by analyzing the importance-satisfaction of a dietary life education program for dietary life education trainees. The results of the rank test for the satisfactory elements of dietary life education were in the order of competence of instructors, educational contents, time of education, educational environment and affordability of tuition. The importance-satisfaction analysis of the contents and construction of the dietary life education program showed that "suitable contents for the theme of the class", "contents and construction of practice class", "diversity of practice menu" and "diversity of educational contents" had high importance and satisfaction scores and therefore, could be maintained at their current levels. Meanwhile, "adequacy of class time" and "contents and construction of theory class" showed low importance and satisfaction scores, requiring a little effort. Whereas, "time and construction of group practice", "structure of textbook for class" and "duration of course and number of classes" showed relatively low satisfaction compared to importance, requiring major efforts for improvement. Similarly, analysis of the lecture element from dietary life education showed that "professional lecture by instructors", "lectures suitable for themes" and "lecture applicable in real life" had relatively low satisfaction compared to importance, requiring major efforts for improvement. In addition, analysis of the educational environment from dietary life education showed that "adequacy of lecture room space", "cooking equipment", "diversity of cooking utensils" and "sanitary condition of cooking utensils" also require major efforts for improvement. Therefore, dietary life education should not be executed with a simple delivery of knowledge but with both theory and practice classes to increase its application in real life, and active and specific efforts are required to nurture professional instructors and establish educational strategies.

• Journal of Applied Reliability
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• v.3 no.2
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• pp.93-101
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• 2003

Life time data analysis requires some time-to-failure data to an extent. Some life tests result in few or no failure. In such cases, it is difficult to access reliability with traditional life tests that record only time to failure. Furthermore, with short product development time, reliability tests must be conducted with severe time constraints. For some devices, it is possible to obtain degradation measurements over time, and these measurements may contain useful information about product reliability. This article describes degradation reliability analysis methods to do inferences and predictions about a failure-time distribution by using software. In addition, the possibility of extension to CBM (Condition Based Maintenance) is suggested as an example of applied degradation data analysis.

• International Journal of Reliability and Applications
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• v.15 no.2
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• pp.125-150
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• 2014

Accelerated life tests (ALTs) are extensively used to determine the reliability of a product in a short period of time. Test units are subject to elevated stresses which yield quick failures. ALT can be carried out using constant-stress, step-stress, progressive-stress, cyclic-stress or random-stress loading and their various combinations. An ALT with linearly increasing stress is ramp-stress test. Much of the previous work on planning ALTs has focused on constant-stress, step-stress, ramp-stress schemes and their various combinations where the stress is generally increased. This paper presents an optimal design of ramp soak-stress ALT model which is based on the principle of Thermal cycling. Thermal cycling involves applying high and low temperatures repeatedly over time. The optimal plan consists in finding out relevant experimental variables, namely, stress rates and stress rate change points, by minimizing variance of reliability function with pre-specified mission time under normal operating conditions. The Burr type XII life distribution and time-censored data have been used for the purpose. Burr type XII life distribution has been found appropriate for accelerated life testing experiments. The method developed has been explained using a numerical example and sensitivity analysis carried out.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.2
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• pp.144-154
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• 2016

HT-PEMFC (high temperature polymer electrolyte membrane fuel cell) using PA (phosphoric acid) doped PBI (polybenzimidazole) membrane has been researched for extending the lifetime. However, the existing work on durability of HT-PEMFC focuses on identifying degradation causes of lab scale. The short life time of HT-PEMFC is still the problem for its commercialization. In this paper, an operating method to maximize life time of 5kW HT-PEMFC stack are proposed. The proposed method includes major steps such as minimization of OCV (Open Circuit Voltage) exposure, control of the proper stack temperature, and N2 purging for the stack. This long life operating method was based on the fragmentary results of degradation from previous research works. Experimentally, the 5 kW homemade HT-PEMFC stack was operated for a long time based on the proposed method and the stack successfully can operate within the desired degradation rate for the target life time.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.397-402
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• 2008

This study was performed to investigate the correlation between changes of feeding behavior of Bemisia tabaci and residual effect of two insecticides, emamectin benzoate and pyridaben, using EPG technique. Waveforms such as non-probe time and total duration of phloem phase of B. tabaci were recorded during three hours using EPG. Relationship between non-probe time and the change of residual effect of two insecticides correlated with more pyridaben than emamectin benzoate. In the relationship between phloem phase time and those of residual effect, emamectin benzoate was more correlated than pyridaben. These results show that the change of feeding behavior of B. tabaci is correlated with the change of residual effect of two insecticides.

• Journal of the Korean Society of Safety
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• v.33 no.6
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• pp.1-7
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• 2018

The Continuous Ship Unloader (CSU) is an equipment that unloads freight from the ship docked in the port to the land. And the design target life time is designed to be 30 to 50 years, and it is classified as a semi-permanent large facility. However, cracks may occur due to structural defects, abnormal loads, and corrosion, and fatigue failure may occur before the design life is reached. In this study, we predicted the remaining life time of the main component of the CSU considering crack. And also proposed inspection cycle for maintenance of CSU based on the results of the remaining life time prediction. For this purpose, the structure, operational stresses of the CSU were analyzed and main members were selected. And tensile tests and fatigue crack propagation tests were performed with SM490YA and SM570TMC, which are used as main materials for CSU.

• Therapeutic Science for Rehabilitation
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• v.9 no.3
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• pp.91-102
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• 2020

Objective : This study investigated the effects of time-use intervention, conducted during 8 weeks, on the life satisfaction and self-esteem of stroke patients. Methods : Twenty-one stroke patients who were divided into an experimental group (n=10) and a control group (n=11), participated in this study from July 2019 to October 2019. Life satisfaction changes were measured using the Life satisfaction scale. Self-esteem changes were measured using the Self-esteem scale. Results : First, comparison between pre and post intervention showed a statistically significant difference in life satisfaction and self-esteem (p<.05). Second, comparison between post intervention groups showed a statistically significant difference in life satisfaction and self-esteem (p<.05). Conclusion : Based on the results from this study, we found that time-use intervention has a positive impact on life satisfaction and self-esteem. Therefore, participating in meaningful occupation performance will improve the mental health and quality of life of stroke patients.

• Journal of Family Resource Management and Policy Review
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• v.19 no.2
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• pp.101-125
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• 2015

Dual-income family is becoming more common in today's society. This study will look at how dual-income households balance between work and life. Specifically, it will study how the families allocate time for work, where they use labor power, and for domestic work and leisure, where they recharge labor power. The data source for this study was the 2009 Korean Time Use Survey. The main results of this research are as follow: The study confirmed that many husbands and wives they still spend much time working. There are differences to spend in restoring labor power; many husbands spend leisure time and many wives spend household labor. Generally in a typical dual-income household, the husband works and enjoys leisure and the wife focuses on working. It was found that the husband and wife in a dual-income family feel time deficient is due to long working hours.

• Corrosion Science and Technology
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• v.12 no.5
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• pp.209-214
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• 2013

In the industry, accelerated corrosion test is used for the life time prediction. When anti-corrosion test proceeds in real environments, it is difficult that we predict and evaluate the corrosion life time because of the long test time such as 10 years or more time. Accelerated corrosion test and Salt spray test are able to test corrosion life time of products in the laboratory instead of outdoor corrosion test. Experimental procedure is selected for the corrosion standard specimen, exposure of the specimens, measurements of the mass loss and evaluating the mass loss data. As a result, the acceleration factor of the accelerated corrosion test to the outdoor corrosion test is 414.8. Therefore we can predict the corrosion life time of carbon steel during a short time period.

• Journal of Families and Better Life
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• v.28 no.4
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• pp.103-115
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• 2010

This study approached the leisure with the step of life cycle, analyzing the process of leisure career and leisure development in individual life. The leisure life cycle leads the other related studies by examining the concepts of continuity, change, leisure socialization, and leisure career. It also analyzes the patterns and the structures of the use of life time, using '2004 Time Use Survey' from the Korea National Statistical Office. As a result, this study suggests new 3 steps of leisure life cycle: participating and expanding stages, selective and concentrating stage, and continuing and absorbed stage. These steps set up the goal of leisure program by the periods. They also can help setting the direction of leisure activities, and can be used as basic data that can make up the leisure activity program models step by step. Moreover, the development of model can be used as valuable information to draw up the plans that can prepare for aging society and demand the support of policy.