• Journal of the East Asian Society of Dietary Life
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• v.21 no.1
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• pp.125-133
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• 2011

This study was carried out to strengthen productivity and employee management through the development of simple pre-processed foods based on Hansik (Korean foods) and to investigate the utilization of fresh vegetable menus, pretreatment, and cooking time in the preparation of vegetable side dishes. The reasons for not using pretreated foods were increased cost, required product size is not available, and not hygienic. The acceptable rate of increase in cost when purchasing simple pre-processed foods was under 10%. The expected developed products of simple pre-processed vegetable foods were balloon flower root salad, seasoned green vegetables, and sheredded white radish. The expected developed products of simple mixed vegetable pre-processed foods were deodeok+balloon flower root and white radish+pear. Based on these findings, to increase the utilization of simple preprocessed foods, development of various product sizes and sauces is needed, cost must be reduced, and hygiene improved.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.75-89
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• 2006

This paper presents a practical and realistic Life-Cycle Cost (LCC) optimum design methodology of steel bridges considering time effect of bridge reliability under environmental stressors such as corrosion and heavy truck traffics. The LCC functions considered in the LCC optimization consist of initial cost, expected life-cycle maintenance cost and expected life-cycle rehabilitation costs including repair/replacement costs, loss of contents or fatality and injury losses, road user costs, and indirect socio-economic losses. For the assessment of the life-cycle rehabilitation costs, the annual probability of failure which depends upon the prior and updated load and resistance histories should be accounted for. For the purpose, Nowak live load model and a modified corrosion propagation model considering corrosion initiation, corrosion rate, and repainting effect are adopted in this study. The proposed methodology is applied to the LCC optimum design problem of an actual steel box girder bridge with 3 continuous spans (40 m+50 m+40 m=130 m), and various sensitivity analyses of types of steel, local corrosion environments, average daily traffic volume, and discount rates are performed to investigate the effects of various design parameters and conditions on the LCC-effectiveness. From the numerical investigation, it has been observed that local corrosion environments and the number of truck traffics significantly influence the LCC-effective optimum design of steel bridges, and thus realized that these conditions should be considered as crucial parameters for the optimum LCC-effective design.

• Structural Engineering and Mechanics
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• v.31 no.1
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• pp.11-24
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• 2009

In China, the oil and natural gas resources of Bohai Bay are mainly marginal oil fields. It is necessary to build both ice-resistant and economical offshore platforms. However, risk is involved in the design, construction, utilization, maintenance of offshore platforms as uncertain events may occur within the life-cycle of a platform under the extreme ice load. In this study, the optimum design model of the expected life-cycle cost for ice-resistant platforms based on cost-effectiveness criterion is proposed. Multiple performance demands of the structure, facilities and crew members, associated with the failure assessment criteria and evaluation functions of costs of construction, consequences of structural failure modes including damage, revenue loss, death and injury as well as discounting cost over time are considered. An efficient approximate method of the global reliability analysis for the offshore platforms is provided, which converts the implicit nonlinear performance function in the conventional reliability analysis to linear explicit one. The proposed life-cycle optimum design formula are applied to a typical ice-resistant platform in Bohai Bay, and the results demonstrate that the life-cycle cost-effective optimum design model is more rational compared to the conventional design.

• Elastomers and Composites
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• v.54 no.1
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• pp.70-76
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• 2019

The function and purpose of the marine rubber fender, to prevent the damage of the ship and the mooring while the ship is being attached to the pier. However, maintenance of the fender after installation is not enough, because it is generally handled as an attachment facility. Estimation the life of a marine rubber fender is important in the maintenance of a port. When manufacturers design and produce marine rubber fenders, they do so according to various conditions such as the reaction force acting on the hull and docking vessel and deformation after absorbing the kinetic energy of the ship. In this study, a method for predicting and evaluating service life from the product design and development stage was established, in order to evaluate the durability of the marine rubber fenders. The SSp-300H and HSP-300H models were used to predict the service life. The method developed in this study, is expected to predict the service life of the marine rubber fender accurately and in a comparatively shorter time, thereby contributing to the evaluation standard and quality stability of the product.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.47-56
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• 2022

The purpose of this study is investigate the effects of quality of life and occupational performance on quality of sleep in college students. Data had been collected from Sep. 1 to Sep. 30, 2021. The subjects of this study were students majoring in occupational therapy at C College situated in C region. For analysis, 103 copies of questionnaire were used. As study instruments, a structured questionnaire incorporating questions about general characteristics, and measurement scales for quality of life, quality of sleep, and occupational performance evaluation were applied. Subjective sleep quality and sleep latency of study participants had lower scores than other components. According to the analysis on different quality of sleep depending on general characteristics, women had more sleep disturbances as they didn't have any part-time job. In terms of the correlation between quality of sleep and quality of life, physical health and total score (quality of life) had correlations with daytime dysfunction. With regard to influential factors on quality of sleep, rest & sleep as a domain of occupational performance and work affected quality of sleep. Students' quality of sleep will be improved if they keep regular habits of living, have rest appropriately for alleviating their stress, and do their jobs with interest and successfully according to a procedure. It is expected that the results of this study will be helpful to care for the health of would-be experts in charge of national health care.

• Journal of applied mathematics & informatics
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• v.8 no.1
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• pp.199-212
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• 2001

We consider a k-out-of-n system with repair under T-policy. Life time of each component is exponentially distributed with parameter $\lambda$. Server is called to the system after the elapse of T time units since his departure after completion of repair of all failed units in the previous cycle or until accumulation of n-k failed units, whichever occurs first. Service time is assumed to be exponential with rate ${\mu}$. T is also exponentially distributed with parameter ${\alpha}$. System state probabilities in finite time and long run are derived for (i) cold (ii) warm (iii) hot systems. Several characteristics of these systems are obtained. A control problem is also investigated and numerical illustrations are provided. It is proved that the expected profit to the system is concave in ${\alpha}$ and hence global maximum exists.

• Journal of Korean Institute of Industrial Engineers
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• v.15 no.1
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• pp.51-63
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• 1989

This paper considers software release problems based on Goel-Okumoto and S-shaped reliability growth models. Test of the software system is terminated after a preassigned time T, and it is released to the operational phase. It is assumed that correction cost of an error is increasing with test or operation time. Optimum software release time is obtained using total expected cost on the software life time as a criterion for optimization. In addition, optimal software release policies under the constraint of a software reliability requirement are discussed.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.3
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• pp.141-147
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• 2018

In a time when product development cycles are getting shorter and shorter, many companies are making efforts to develop products with high reliability in a short period of time, accelerated life test is widely used as a method to quickly evaluate reliability. Accelerated life test reduces the test life or the life of the product from the observed data by shortening the lifetime of the product or abruptly lowering the performance under the worse condition than the actual condition in order to shorten the test cost or the test time. In this paper, BL3640A-06P+RB35, DC12V model, which is used in the support device of an automatic rotation type digital signage, which display various information such as textures and images on a display screen in a public place or a commercial space, BLDC motors were subjected to a constant stress test and at the rotational speed of 1rpm, $180^{\circ}$ rotation and reverse rotation under actual use conditions, the stress was imposed on the rotating speed of 2rpm and the weight of the actual installed product from 22.2kgf to 10kgf were installed. The lifetime of the actual use environment condition is 23,545 hours and the rotation speed is accelerated. The life time of the acceleration condition with the additional weight is 1,380 hours. The acceleration factor is calculated as 17.06, the one year guarantee test day is 235 days to 14 days, of the period from 470 days to 28 days, and the third year from 704 days to 42 days. The test date of the BLDC motor was tested on the shortened test date, and the rotational speed and the current value were measured. It is found that there is no defect even if it operates as the test date corresponding to the specified one year warranty period and the 3 year accelerated life test which is experimented. Using the statistical technique of the regression analysis the expected time for the motor to defect to #4 samples was 20 years.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.2
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• pp.161-174
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• 2004

This study was accomplished to investigate the dietary life and their opinion about the food-nutrition labelling of 20's∼60's housewives in Seoul and Kyeonggi area. The results were as follows. Among subjects, 63.5% didn't make a budget for the food expenses because they did not practice habitually not only the budget-planning, but also the menu planning. They often brought the Kimchi from the relatives rather than preparing it by themselves. On the other hand, they often purchased the soy sauce, soybean paste and soybean paste mixed with red pepper. When purchasing the foods, the importantly considered factors were in the order of freshness, taste and nutritional quality. They thought the processed foods were convenient and economic in terms of time but were not beneficial for the health and low in the nutritional quality. The confirming degree of food-nutrition labelling was very low, but in case of confirming, they often confirmed the manufactured date and the expiration date in order to confirm the stability. The degree of confidence and understanding about food-nutrition labelling of subjects was average 3.3 out of 5. They wanted the nutrient content the most in the food-nutrition labelling on the package. They preferred it as the types of picture and graph rather than the table and descriptiption. The expected effects of food-nutrition labelling was that they might be helpful to select the foods for the prevention of the adult diseases and obesity. From the results, we proposed that the agencies and nutrition concerned consumers should make an every efforts for the successful implementation of food-nutrition labelling system.

• Journal of Agricultural Extension & Community Development
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• v.16 no.4
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• pp.713-742
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• 2009

In the near future, the multicultural families are expected to be the majority of population living in the rural area, which is an aged and small-scaled society. Moreover, they are expected to have an important role in sustaining the culture of agriculture and a rural community. Therefore, it is very important for them to adjust and settle urgently as well as to develop a policy and social services for the adjustment and settlement. The purpose of this study is to identify different aspects of the participation in agricultural, social, and job activities of married immigrant women in a Korean rural area as well as to investigate the change of life satisfaction resulting from the l activities. The following findings were established from this study. First, married immigrant women participate in local social and agricultural activities in a Korean rural area more frequently than in their own country. However, the frequency of their participation in job activity in a Korean rural area is lower than in their own country. Second, the main factor that prevents married immigrant women from participating in agricultural activity in a Korean rural area is to carry out childcare, household chores, and farming at the same time. Their low participation in social activity and job activity mostly results from their lack of fluency in Korean. Third, married immigrant women score higher in the change of life satisfaction after participating in social activity and job activity than in agricultural activity.