• Proceedings of the Korean Society of Crop Science Conference
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• 2019.04a
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• pp.138-138
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• 2019

• Journal of Korean society of Dental Hygiene
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• v.21 no.6
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• pp.741-750
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• 2021

Objectives: To provide basic data for oral health policy by identifying the differences in oral health behaviors and conditions among middle-aged people in their 40s and 50s and relating these to their health-related quality of life, and to identify factors affecting health-related quality of life. Methods: In this study, secondary data from the National Health and Nutrition Examination Survey were used. Data were gathered from 8,127 participants, of which 2,353 were middle-aged (40-59 years old). Covariance analysis was performed using a complex sample general linear model to investigate the changes in the subjects' health-related quality of life (EQ-5D) according to their general characteristics, oral health behaviors, and oral health status. Results: Oral health behavior was not significantly related to health-related quality of life. In contrast, a higher oral health status (chewing function) was associated with better health-related quality of life. Conclusions: In conclusion, this study suggested a close relationship between oral health status (chewing function) and health-related quality of life. Therefore, it is necessary to recognize the importance of oral health in improving the health-related quality of life of middle-aged people in their 40s and 50s, as well as in informing oral health policies and preventive measures for individuals and communities.

• International Journal of Reliability and Applications
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• v.1 no.1
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• pp.89-104
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• 2000

Accelerated testing consists of a variety of test methods for shortening the life of products or hastening the degradation of their performance. This paper presents practical, modern statistical methods for evaluating the reliability of Nickel-Cadmium batteries at their design temperature of 2$0^{\circ}C$ by accelerated life test. Batteries have been life tested at three high temperature conditions, 50, 60, 7$0^{\circ}C$, respectively to yield failures quickly. The failures have been observed and judged by means of charge and discharge current integration. Analyses of life data from those conditions resulted in the Weibull distribution, which has been verified on the ground of the Kolmogorov-smirnov test and the pairwise t-test. Life data are modeled according to the Arrhenius life-temperature relationship. The mean life of tested batteries is assessed at about 590 cycles, and the activation energy of this chemical reaction is concluded to be 0.39eV as results. This study provides procedures for estimating the reliability of batteries in a short period, which has little been possible in domestic industries. The results can be applied in many fields such as proof testing, acceptance testing, and estimating assurance periods.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.445-450
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• 2003

This study was performed 10 develop the accelerated life test method using Weibull-IPL(Inverse Power Law) model for mechanical components. Weibull-IPL model is concerned with determining the assurance life with confidence level and the accelerated life test time From the relation of weibull distribution factors and confidence limit, the testing times on the no number of failure acceptance criteria arc determined. The mechanical components generally represent wear and fatigue characteristics as a failure mode. IPL based on the cumulative damage theory is applied effectively the mechanical components to reduce the testing time and to achieve the accelerating test conditions. As the actual application example, accelerated life test method of agricultural tractor transmission was described. Life distribution of agricultural tractor transmission was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 3,000 hours and 90% confidence level for one test sample. According to IPL, because test time call be shorten in case increase test load test time could be reduced by 482 hours when we put the load 1.1 times of rated load than 0.73 times of rated load that is equivalent load calculated by load spectrum of the agricultural tractor. This time, acceleration coefficient was 11.7.

• Journal of Biosystems Engineering
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• v.34 no.5
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• pp.325-330
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• 2009

This study was performed to develop accelerated life test methods for agricultural tractor transmission receiving variable load. To acquire parameters for calculation of accelerated life test, endurance tests were performed under different torque conditions. Test results showed that the shape factor of Weibull distribution was 1.5 and fatigue damage exponent was 5.4. The calculated test time was 5,877 hours under the conditions of average life (MTBF) 3,000 hours and 90% reliability for one test sample. According to the linear cumulative damage rule, test time could be reduced using increased test load. Test time could be reduced by 252 hours when 1.2 times of the rated load compared with 0.67 times of the rated equivalent load calculated by load spectrum of the agricultural tractor. Calculated acceleration coefficient was 23.3.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.162-167
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• 2002

An automotive wheel bearing is one of the most important components to guarantee the service life of a passenger car. The endurance life of a bearing is affected by many parameters such as material properties, heat treatment, lubrication conditions, temperature, loading conditions, bearing geometry, internal clearance and so on. In this paper, we analyze the relation between loads and deformations of wheel bearing units. On the basis of it, we calculate the endurance life of wheel bearing units and suggest a method to determine the initial contact angle to achieve a maximum endurance life with considering stress concentration.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.477-481
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• 2003

The community escape response of Rhodobacter sphaeroides is exerted through the action of CerR and CerI, which code for a LuxR-type regulatory protein and acylhomoserine lactone synthase, respectively. Deletion of chromosomal DNA including cerR and cerI (mutant RI) or insertional interruption of cert (mutant AP3) resulted in two-fold increase in the cellular poly-${\beta}$-hydroxybutyrate (PHB) content In comparison with the wild-type under aerobic growth conditions. The PHB synthase (PhbC) activities of the cer mutants were doubled, and the enzyme expression was regulated at the level of phbC transcription. Thus, CerR, possibly in response to autoinducer (AI), appears to modulate the PHB content of aerobically grown cells by downregulating phbC transcription.

• Journal of the East Asian Society of Dietary Life
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• v.27 no.2
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• pp.194-203
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• 2017

Mealworm, a type of edible insect, is a superior food material suitable for industrial products. In this study, four different defatted mealworm powders were prepared to determine proper manufacturing conditions. Solvent extraction method reduced lipid contents of mealworms more than pressed mealworms, and lowered lipid contents caused bright colors and good physicochemical properties for powders. In comparison, differences among milling machines used for making powders were strongly related with average size of particles. Meanwhile, the predicted shelf-life of defatted mealworm powders judged by accelerated experiments was 1 year or longer. To enhance shelf-life of mealworm powders, addition of tocopherol to mealworm powders at a concentration of 0.2% could intensify oxidative stability and microbial inhibition.

• Journal of Families and Better Life
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• v.8 no.2
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• pp.87-100
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• 1990

This study was carried out in an attempt to establish a preliminary scale for measuring $\boxDr$Quality of Life$\boxUl$ of Korean farm households, Data from randomly selected 318 farm households through our the country were analysis. The main results of this study were summarized as follows; 1) The objective levels of living conditions were relatively low in dietary life, healthy & sanitation, and financial stability and were relatively high in family relationship, household work and housing environment. 2) The subjective satisfaction level was lowest in leisure and were relatively high in family relationship and health & sanitation. 3) A comparison of objective level of living conditions and subjective satisfaction level suggested th score of the latter were higher than the former in dietary life and health & sanitation. In the contrary to this, the scores of the former were higher than the latter in housing environment, household work, child education, leisure and family relationship. In particular, the score of the subjective satisfaction level were much higher in housing environment and household work.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.2
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• pp.131-139
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• 2001

The physicochemical and sensory characteristics of brown rice flakes by different processing conditions such as flaking Process and their heat treatments were investigated to establish the brown rice flake processing procedure. To successfully make the compressed rice grain type flakes, the most appropriate water steeping conditions were 5 hours at 60'C. The brown rice flakes by compressed flaking procedure and heat treatment with microwave toasting showed the best crispiness-texture that tested from textrometer or sensory evaluation, and there was no significant difference between the source of rice varieties. The water absorption index(WAI) of tested flakes were negatively correlated with the water soluble index( WSI) and positively correlated with bowl life. The flakes made by compressed flaking procedure and heat treatment with microwave toasting showed longer bowl life, which is the length of the time that the cereal can retain its crispness after being soaked in milk.