• 한국가스학회:학술대회논문집
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• 2001.10a
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• pp.161-166
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• 2001

• Journal of Power System Engineering
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• v.19 no.4
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• pp.24-29
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• 2015

This paper designs a looper-tension controller for strip top-tail parts in hot strip finishing mills. A three-degree linear model of the looper-tension system is derived by a Taylor's linearization method, where the actuator's dynamics are ignored because of their fast responses. A feedforward shaping controller for the strip top part and a feedforward model reference controller for the strip tail part are respectively designed, they are combined with an ILQ(Inverse Linear Quadratic optimal control) feedback controller for the strip middle part. It is shown from by a computer simulation that the proposed controller is very effective to the strip top-tail parts including the middle part.

• Computers and Concrete
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• v.27 no.3
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• pp.269-282
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• 2021

A dynamic analytical solution for a simply supported, rectangular functionally graded plate with a porous middle layer under time-dependent load based on a refined third-order shear deformation theory with a cubic variation of in-plane displacements according to the thickness and linear/quadratic transverse displacement is presented. The solution achieved in the trigonometric series form and rests on the Green's function method. Two porosity types and their influence on material properties, and mechanical behavior are considered. The network of pores is assumed to be empty or filled with low-pressure air, and the material properties are calculated using the power-law distribution idealization. Numerical calculations have been carried out to demonstrate the accuracy of the kinematic model for the dynamic problem, the effect of porosity, thickness of porous layers, power-law index, and type of loading on the dynamic response of an imperfect functionally graded material plate.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.3
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• pp.547-553
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• 2024

Hydrogen is considered a key energy source to achieve carbon neutrality through the global goal of 'Net Zero'. Due to limitations in domestic green hydrogen production, Korean companies are interested in importing green hydrogen produced overseas. Because Australia and the Middle East possess high-quality renewable energy resources, they are attracting attention as suitable regions for producing green hydrogen using renewable energy. The cost of constructing and operating a green ammonia plant varies depending on the region. In this study, an economic feasibility comparison of green ammonia plant construction in Australia and the Middle East is conducted. Through this, it is expected to contribute to the economic analysis and feasibility analysis of the project to import hydrogen in the form of green ammonia into Korea.

• Research in Community and Public Health Nursing
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• v.31 no.2
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• pp.156-165
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• 2020

Purpose: This study was performed to identify the factors influencing the fear of dementia in middle-aged and older adults. Methods: Data on the characteristics, dementia knowledge, dementia attitude, dementia health beliefs, and fear of dementia of 156 participants were collected from January 20 to March 22, 2018, using a structured questionnaire. The data were analyzed with the SPSS/WIN 21.0 program for descriptive statistics, using an independent t-test, one-way analysis of variance, Pearson's correlation coefficient, and stepwise multiple regression. Results: Significant factors associated with fear of dementia among middle-aged and older adults were subjective life satisfaction (F=3.72, p=.006) and regular exercise (t=6.05, p=.015). Fear of dementia has positive correlations with dementia attitude, perceived susceptibility, perceived severity, and perceived barrier. The determining factors affecting fear of dementia in middle-aged and older adults were perceived severity (β=.46, p<.001), followed by a perceived barrier (β=.20, p=.004) and perceived susceptibility (β=.17, p=.023), and the explanation power was about 47.8%. Conclusion: The results suggest that perceived severity, perceived barrier, and perceived susceptibility be considered in developing the nursing interventions to increase perceived severity, perceived susceptibility, and to decrease perceived barrier to dementia by evaluating dementia health beliefs to manage the fear of dementia among middle-aged and older adults.

• Research in Community and Public Health Nursing
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• v.24 no.4
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• pp.471-479
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• 2013

Purpose: This study was conducted to identify factors for smoking middle school students' intention to quit smoking on the basis of the social influence and self-efficacy [ASE] model. Methods: Data were collected from 2,015 students from five middle schools in Daegu with a structured questionnaire in March, 2013 and analyzed by using $x^2$-test, ANOVA, pearson's correlation and multiple regression analysis. Results: The smoking rate was 6.1% among the total subjects and 85.4% of the smokers had intention to quit smoking. The mean value of attitude toward quitting smoking was $2.15{\pm}0.34$, that of social influence $3.38{\pm}0.65$, and that of self-efficacy $2.84{\pm}0.95$. The multiple regression analysis showed an explanatory power of 24.7%, and experience of trying to quit smoking was the strongest factor affecting the intention to quit smoking (${\beta}$=.34, p<.01), followed by school years and social influence. Conclusion: In order to increase smoking middle school students' intention to quit smoking, intervention strategies are needed to increase positive social influence or to offer public information to younger smoking students in low school years.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.12
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• pp.1948-1952
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• 2012

The paper presents modal testing and analysis in order to obtain the dynamic characteristics of a middle spacer grids of a nuclear fuel rod. A spacer grid is one of the important structural elements supporting nuclear fuel rods. Such a fuel rod can be oscillated by its thermal expansion, neutron irradiation and etc. due to cooling water flow under the operation of a nuclear power plant. When the fuel rod vibrates, fretting wear due to repeated friction motion between the fuel rods and spacer grids can be occurred, and so the fuel rod is damaged. In this paper, through modal analysis and testing, natural frequencies and modes of a middle spacer grid were calculated, and the following conclusions were obtained. Firstly the numerical first-seven natural frequencies for spacer grids of a fuel rod having complicated structures have a small difference within 3.8% with experimental natural frequencies, and so the suitability of simulation results was verified. Secondly, experimental mode shapes for a middle spacer grid of a nuclear fuel rod were verified by obtaining lower non-diagonal terms through MAC(Modal Assurance Criteria), and were confirmed by the simulation modes.

• Women's Health Nursing
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• v.5 no.2
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• pp.230-246
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• 1999

The purpose of this study was to identify the degree of hardiness, knowledge of menopause, menopausal management of the middle aged women to identify the variables that show differences in the hardiness, knowledge of menopause and menopausal management of middle aged women and to investigate the relation ship among hardiness, menopausal knowledge and menopausal management of the middle aged women. The subjects were 132 middle-aged women and belonged to the age between 40 and 60. They were selected in Pusan, Korea. Data were collected from Oct. to Nov., 1998 by means of a structured questionnaire. The instruments used for this were the hardiness scale developed by Song In Sook and Song Ae Ri and the menopausal management scale developed by Song Ae Ri. The results were as follows 1. The mean score of hardiness was 2.83, in minimum score 1.24 tomaximun score 5.04. The mean score of knowledge of menopausal was 0.68, in minimum score 0.21 to maximum score 0.71. the mean score of menopausal management was 2.26, in minimum score 1.35 to maximum score 3.18. 2. In the relation between social demographic and hardiness there were significant differences in the health condition, income, supportive person. In relation between social demographic and menopausal knowledge there were significant differences in the health condition, family members. In the menopausal management there was significant differences in the marital state. 3. There was significant correlation between the hardiness and menopausal management of middle aged women (r=-0.208, p=0.017). 4. There was not significant correlation between the knowledge of menopause and menopausal management (r=0.001, p=0.992). These findings suggest the need to develop nursing strategy to improve the power of hardiness in middle aged women. hardiness is important to improve the menopausal management of middle aged women.

• Journal of Educational Research in Mathematics
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• v.8 no.2
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• pp.527-540
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• 1998

In the teacher's guide of mathematics textbook for the 1st grade of the middle school, the clear and logical reason why the multiplication of negative number to negative number makes positive number, and $a^{-m}$ with a>0 and m>0, is defined by ${\frac{1}{a^m}}$ is not given. When we define the multiplication or the power by successive addition or successive multiplication of the same number, respectively, we encounter this ambiguity, in the case that the number of successive operations is negative, In this paper, we name this number, negative counting number, and we make the following more logical and intuitive definition, which is "negatively many successive operations is defined by positively many successive inverse operations." According to this new definition, we define the multiplication by the successive addition or the successive subtraction of the same number, when the multiplier is positive or negative respectively, and the power by the successive multiplication or the power is positive or negative, respectively. In addition, using this new definition and following the E.R.S Instruction strategy which revised and complemented the Bruner's E.I.S Instruction strategy, we develope new teaching model available in the 1st grade class of middle school where the concept of integers, three operations of integers are introduced.ntroduced.

• Journal of The Korean Association For Science Education
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• v.24 no.4
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• pp.748-757
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• 2004

When teachers for the gifted express metaphors about their teaching, they may develop better understanding and conceptualizing of teaching and enable to choose appropriate teaching strategies for optimizing individualized learning of the gifted. Therefore, the purpose of this study includes to explore metaphors about science teachers' teaching for the gifted in middle schools and classify into types of metaphors. The survey was administered and completed survey instruments by 66 science teachers for the gifted at gifted educational institutions affiliated with local offices of education and 18 science teachers at middle schools were analyzed. It was revealed that science teachers for the gifted described seven types of metaphors about their teaching with characteristics of student-centered (counsel, helper, etc.), teacher-centered (judge, captain, etc.), or student-teacher-interacted (painter, nurse, etc.) types. More than 60% of teachers described their teaching as either student-centered or student-teacher-interacted types. However, percentage of teachers for the teacher-centered and power-oriented type was higher for science teachers for the gifted (33%) than science teachers for regular students (22%). It was also found that female science teachers for the gifted showed higher percentage for teacher-centered and power-oriented (35%) than male teachers (28%) and teachers with BS degree showed higher percentage for student-centered and service-oriented type (33%) than teachers with MS degree (27%). In addition biology teachers for the gifted also were appeared to be more teacher-centered and power-oriented type (60%) than physics (21%), chemistry (6%), and earth science (33%).