• 한국수학교육학회지시리즈B:순수및응용수학
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• 제28권4호
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• pp.387-398
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• 2021

In this paper, we will find solutions and investigate the superstability bounded by constant for the p-radical functional equations as follows: $f\(\sqrt[p]{\frac{x^p+y^p}{2}}\)^2-f\(\sqrt[p]{\frac{x^p-y^p}{2}}\)^2=\;\{(i)\;f(x)f(y),\\(ii)\;g(x)f(y),\\(iii)\;f(x)g(y),\\(iv)\;g(x)g(y).$ with respect to the sine functional equation, where p is an odd positive integer and f is a complex valued function. Furthermore, the results are extended to Banach algebra.

• 대한수학회보
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• 제58권3호
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• pp.669-688
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• 2021

The aim of this paper is to prove the existence of an admissible inertial manifold for mild solutions to infinite delay evolution equation of the form $$\{{\frac{du}{dt}}+Au=F(t,\;u_t),\;t{\geq}s,\\\;u_s({\theta})={\phi}({\theta}),\;{\forall}{\theta}{\in}(-{{\infty}},\;0],\;s{\in}{\mathbb{R}},$$ where A is positive definite and self-adjoint with a discrete spectrum, the Lipschitz coefficient of the nonlinear part F may depend on time and belongs to some admissible function space defined on the whole line. The proof is based on the Lyapunov-Perron equation in combination with admissibility and duality estimates.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.95-96
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• 2022

Carbon nanotubes has a positive effect on the mechanical properties, functionality, and durability of cement-based materials. In this study, carbon nanotube solutions mixed with two different types of superplasticizers were dispersed by high-pressure homogenizer, and used for preparation of cement paste. The 7and 28day compressive strength were evaluated.

• 무역학회지
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• 제45권2호
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• pp.17-29
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• 2020

This study analyzed that the effects of AEO MRA benefit on decreasing of trade cost and the strategies for expanding of trade. It uses the system GMM for effective solutions of endogenous matter with lagged dependent variable. In terms of the result of analysis, AEO MRA has a positive effect on decreasing of trade cost, especially this study proved the result of previous study AEO MRA expanded the trade through improving the time required for customs clearance and deregulation of non-tariff barriers. In conclusion, this study proposes the policy fo AEO MRA by analyzing the trade cost of AEO MRA by using the system GMM.

• 대한수학회논문집
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• 제38권4호
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• pp.1045-1061
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• 2023

Using variational methods, Krasnoselskii's genus theory and symmetric mountain pass theorem, we introduce the existence and multiplicity of solutions of a parameteric local equation. At first, we consider the following equation $$\{-div[a(x,{\mid}{\nabla}u{\mid}){\nabla}u]\,=\,{\mu}(b(x){\mid}u{\mid}^{s(x)-2}-{\mid}u{\mid}^{r(x)-2})u\;in\;{\Omega},\\u\,=0\,on\;{\partial}{\Omega},$$ where Ω⊆ ℝ^N is a bounded domain, µ is a positive real parameter, p, r and s are continuous real functions on ${\bar{\Omega}}$ and a(x, ξ) is of type |ξ|^p(x)-2. Next, we study boundedness and simplicity of eigenfunction for the case a(x, |∇u|)∇u = g(x)|∇u|^p(x)-2∇u, where g ∈ L^∞(Ω) and g(x) ≥ 0 and the case $a(x,\,{\mid}{\nabla}u{\mid}){{\nabla}u}\,=\,(1\,+\,{\nabla}u{\mid}^2)^{\frac{p(x)-2}{2}}{\nabla}u$ such that p(x) ≡ p.

• 대한수학회보
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• 제61권2호
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• pp.541-556
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• 2024

In this paper, we consider a model problem arising from a classical planar Heisenberg ferromagnetic spin chain $-{\Delta}u+V(x)u-{\frac{u}{\sqrt{1-u^2}}}{\Delta}{\sqrt{1-u^2}}={\lambda}{\mid}u{\mid}^{p-2}u$, x ∈ ℝ^N, where 2 ≤ p < 2^*, N ≥ 3. By the Ekeland variational principle, the cut off technique, the change of variables and the L^∞ estimate, we study the existence of positive solutions. Here, we construct the L^∞ estimate of the solution in an entirely different way. Particularly, all the constants in the expression of this estimate are so well known.

• International Journal of Advanced Culture Technology
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• 제12권1호
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• pp.234-241
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• 2024

In higher education, integration of technologies - particularly generative artificial intelligence (AI) such as ChatGPT - has become increasingly widespread, serving numerous purposes to its stakeholders. While users acknowledge the utility of technology, concerns have emerged regarding its misuses. The present study is designed to investigate authentic perspectives and opinions of college freshman students to critically address the relevant concerns, and suggest meaningful solutions. To this end, seven college freshman student participants were recruited in a four-days-long online questionnaire. Their responses indicated that the college student participants appear to find ChatGPT positive in terms of its practicality and usefulness. However, they also showed concerns about a few potential issues (i.e., possible plagiarism and copyright problems). With recommendations the student participants suggested to reduce the aforementioned problems, the article discusses implications of the findings, providing valuable insights into the balance between implementation of AI technologies and dealing with the associated challenges in higher education in general.

• 한국보건간호학회지
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• 제10권2호
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• pp.146-161
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• 1996

This study was purposed to find health promotion and care needs of the elderly in rural area of Korea. As the rural elderly are limited in accessibility to health care resources and could not immediately solve their health care needs when they need. health promotion and care services are expected to bring better and more practical solutions of their health care needs. Thus, the type of health care services to be developed in Korea rural area is discussed to have emphasis on health care service component in addition to health promoting components. Methods of this study was based on survey data analysis : total 322 persons aged older than 55 living at one 'Kun' in Korea administrative unit were interviewed by health workers working at the region and also get trained for this study data collection. The data collection interview was continued from February till May in 1996. The interview questions were modified with adjustment to Korea situation. with basis of the WHO's health promotion program components. The collected data were analyzed using SAS program for frequency, correlation, regressions. The major findings were as follows : (1) $74.8\%$ of the surveyed were sick at the survey time point. and $95.9\%$ known the diagnosis name of the disease. The most frequently complained diseases were Muscular-Skeletal diseases $(43.7\%)$. $34\%$ of those sick had never treated or discontinued therapeutic procedures. so that shown the necessity of systematic and usual health care services with health promotion program development for the elderly. (2) The percent of those who make social participation was $95.3\%$. and the activities were visiting neighbors $(70.4\%)$ and lack of qualified social activity programs. (3) $78.1\%$ of the surveyed had health counseling and education from professional health workers. Those ceased smoking and drinking were $59.6\%,\; 60.3\%$. respectively. Those had no application of therapeutic drugs or nutrion supplements was $40.7\%\;and\;94.1\%$ had regular meals. Those practiced exercises was low remarking $17.7\%$. (4) Positive health behaviors were better carried out by sick groups than by the healthier. except smoking. regular meals. and exercise. $17.5\%$ of sick group smoke more than one case of cigarettes. in contrast to $9.5\%$ of the healthier. (5) Mental health status was heathier among positive health behavior earners. Health counseling and education shown better score of mental health than those never counseled. (6) Positive health behavior practice frequency did not show significant differences when crossed by social activity participation status. (7) Health behaviors of the rural elderly people were carried out better when they had positive 'continuency in therapeutic procedure' 'health status'. 'familial relationship'. 'Health Status' of the rural olderly were explained by 'exercise'. 'drinking'. 'familial relationship'. 'activities of daily living'. Thus, health behaviors practice mutually interact with health status. In conclusion. the health promotion and care program component are recommended to include ation on the necessity of positive health promotion active social acitivities. pleasant life style, adaption into changes on the elderly, safety in residential area. community acitivity and resource utilization. etc .. in addition to the elderly's disability and sickness caring services.

• The Journal of Advanced Prosthodontics
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• 제9권3호
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• pp.200-207
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• 2017

PURPOSE. In this study, three bioceramic materials, [IPS Empress CAD (Ivoclar), IPS e.max CAD (Ivoclar), and Lava Ultimate CAD (3M ESPE)] were treated with three commercial mouthrinses [Listerine, Tantum Verde, and Klorhex]; and changes in colour reflectance and surface roughness values were then quantitatively assessed. MATERIALS AND METHODS. One hundred and twenty ceramic samples, with dimensions of $2{\times}12{\times}14mm$, were prepared and divided into nine sample groups, except three control samples. The samples were immersed in the mouthrinse solutions for 120 hrs, and changes in colour reflectance and surface roughness values were measured by UV light spectrophotometry (Vita Easyshade; VITA Zahnfabrik) and by profilometer device (MitutoyoSurftest SJ-301), respectively. The change of surface roughness was inspected by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). RESULTS. There was a positive correlation between the ${\Delta}E$ and increase in the surface roughness. Two of the ceramic materials, IPS Empress and Lava Ultimate, were affected significantly by the treatment of the mouthrinse solutions (P<.05). The most affecting solution was Tantum Verde and the most affected material was Lava Ultimate. As expected, the most resistant material to ${\Delta}E$ and chemical corrosion was IPS e max CAD among the materials used. CONCLUSION. This work implied that mouthrinse with lower alcohol content had less deteriorating effect on colour and on the surface morphology of the bioceramic materials.

• Korea-Australia Rheology Journal
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• 제15권3호
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• pp.131-150
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• 2003

A new numerical algorithm of finite element methods is presented to solve high Deborah number flow problems with geometric singularities. The steady inertialess planar 4 : 1 contraction flow is chosen for its test. As a viscoelastic constitutive equation, we have applied the globally stable (dissipative and Hadamard stable) Leonov model that can also properly accommodate important nonlinear viscoelastic phenomena. The streamline upwinding method with discrete elastic-viscous stress splitting is incorporated. New interpolation functions classified as rational interpolation, an alternative formalism to enhance numerical convergence at high Deborah number, are implemented not for the whole set of finite elements but for a few elements attached to the entrance comer, where stress singularity seems to exist. The rational interpolation scheme contains one arbitrary parameter b that controls the singular behavior of the rational functions, and its value is specified to yield the best stabilization effect. The new interpolation method raises the limit of Deborah number by 2∼5 times. Therefore on average, we can obtain convergent solution up to the Deborah number of 200 for which the comer vortex size reaches 1.6 times of the half width of the upstream reservoir. Examining spatial violation of the positive definiteness of the elastic strain tensor, we conjecture that the stabilization effect results from the peculiar behavior of rational functions identified as steep gradient on one domain boundary and linear slope on the other. Whereas the rational interpolation of both elastic strain and velocity distorts solutions significantly, it is shown that the variation of solutions incurred by rational interpolation only of the elastic strain is almost negligible. It is also verified that the rational interpolation deteriorates speed of convergence with respect to mesh refinement.