• Communications of the Korean Mathematical Society
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• v.31 no.3
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• pp.495-505
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• 2016

Let $f:{\mathbb{R}}^3{\rightarrow}{\mathbb{R}}$. In this paper we prove the stability of functional inequalities ${\mid}f(ux+vy,uy-vx,zw)-f(x,y,z)f(u,v,w){\mid}{\leq}{\phi}(u,v,w)$ or ${\phi}(x,y,z)$, ${\mid}f(ux-vy,uy-vx,zw)-f(x,y,z)f(u,v,w){\mid}{\leq}{\phi}(u,v,w)$ or ${\phi}(x,y,z)$ for all $x,y,z,u,v,w{\in}{\mathbb{R}}$. Furthermore, we give refined descriptions of bounded functions satisfying the inequalities as in Albert and Baker [1].

• Journal of Information Technology Applications and Management
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• v.14 no.4
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• pp.61-74
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• 2007

In this paper we consider the Digital Multimedia Broadcasting (DMB) Service that starts recently in Korea and gains popularity. DMB makes it possible to watch high quality TV programs while we are in motion. The service provider or the service researcher are interested in the factors that influence the user's choice of new service such as DMB. Understanding the factors make them create the powerful marketing strategies and develop the new service or product that is attractive for users. We therefore find the factors influencing the user's choice of DMB service, and propose a model for analyzing the relationship between the factors and the intention of buying. The model is based on the Technology Acceptance Model (TAM). We extend the TAM by adding factors including functional attributes of DMB service. We survey the significant functional attributes influencing the intention of buying by using the proposed model.

• Journal of Distribution Science
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• v.19 no.10
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• pp.5-15
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• 2021

Purpose: This study aims to present individual motivation and channel characteristics affecting omnichannel service use, as well as the effect relationship of the brand factor on consumption value, service satisfaction, and continuous usability based on convenience store pickup service, one of online shopping customers' omnichannel use services. Primarily, this study divided consumption value into emotional value and functional value and examined the consumption value characteristics of omnichannel-based pickup service customers. Research design, data and methodology: A questionnaire survey was carried out targeting 324 consumers having the omnichannel-based pickup service user experience in online shopping in Korea. A confirmatory factor analysis and path analysis were carried out based on the structural equation to verify hypotheses. Results: According to the analysis result, individual motivation affected the emotional value, and the omnichannel characteristics affected functional value. The brand effect influenced both emotional and functional values. The emotional value affected continuous use intention, and the functional value affected service satisfaction. Conclusions: Therefore, consumers' emotional and functional values showed differences in consumption behavior. In online shopping companies' marketing strategy construction for omnichannel, it was confirmed that a differentiated approach is needed depending on the strategic goal of satisfaction improvement and continuous use intention consolidation.

• The Korean Journal of Food & Health Convergence
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• v.8 no.1
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• pp.21-30
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• 2022

This study proposed a multiple regression equation for predicting VO2max of elderly men and women using functional performance variables required to conduct daily activities. The subjects of this study were 58 elderly men (72.4±5.9 yrs) and 117 elderly women (73.4±4.5 yrs) aged 65-90 who belong to the senior welfare center. The maximal graded exercise test using a cycle ergometer and functional performance representing muscle strength, endurance, static and dynamic flexibility, mobility, and agility were measured. For statistical processing, multiple regression analysis was performed, and the statistical significance level was α = .05. As a result, the VO2max estimation formula for the elderly was 0.419 (standing up and sitting down a chair) + 0.199 (leg endurance against wall) + 5.383, and R2=0.406. In addition, the VO2max estimation formula for elderly women is - 0.737 (standing up from a supine position) - 0.144 (waking around two cones in a figure 8) - 0.135 (%body fat) + 0.042 (one leg balance with eyes open) + 29.395, R2=0.367 was calculated. The conclusion is that if the maximal graded exercise test is not available, it is considered that VO2max of the elderly can be predicted properly by using the estimation formula calculated based on the functional performance variable.

• Korean Journal of Ecology and Environment
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• v.57 no.2
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• pp.111-122
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• 2024

Zooplankton biomass is essential for understanding the quantitative structure of lake food webs and for the functional assessment of biotic interactions. In this study, we aimed to propose a biomass (dry weight) estimation method using the body length of cyclopoid copepods. These copepods play an important role as omnivores in lake zooplankton communities and contribute significantly to biomass. We validated several previously proposed estimation equations against direct measurements and compared the suitability of prosomal length versus total length of copepods to suggest a more appropriate estimation equation. After comparing the regression analysis results of various candidate equations with the actual values measured on a microbalance-using the coefficient of variation, mean absolute error, and coefficient of determination-it was determined that the Total Length-DW exponential regression equation [W=0.7775×e^2.0183L; W (㎍), L (mm)] could be used to calculate biomass with higher accuracy. However, considering practical issues such as the morphological similarity between species and genera of copepods and the limitations of classifying copepodid stages, we derived a general regression equation for the pooled copepod community rather than a species-specific regression equation.

• The Korean Journal of Community Living Science
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• v.26 no.3
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• pp.523-540
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• 2015

This study examines the structural relationships between service quality, satisfaction, and behavioral intentions in responsible tourism. In particular, the study focuses on moderating effects of age. Data were collected from 471 tourists from seven responsible tourism agencies. SPSS 20.0 and AMOS 18.0 were used for frequency, reliability, exploratory factor, confirmatory factor, and path analyses. The results of a exploratory factor analysis yield two dimensions of service quality (functional quality and technical quality). The results of structural equation modeling indicate that functional quality and technical quality had positive effects on satisfaction, which in turn had a positive effect on behavioral intentions. In addition, age moderated the relationships between service quality, satisfaction, and behavioral intentions such that functional quality had a positive effect on satisfaction in the group of tourists in their twenties and thirties and that functional quality and technical quality were important factors for tourists in their forties. The results are expected to help responsible tourism communities better manage service quality to increase tourist satisfaction.

• Journal of applied mathematics & informatics
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• v.31 no.3_4
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• pp.491-498
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• 2013

This note is concerned with the uniform $L^p$-continuity of solution for the stochastic differential equations under Lipschitz condition and linear growth condition. Furthermore, uniform $L^p$-continuity of the solution for the stochastic functional differential equation is given.

• Korean Journal of Mathematics
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• v.19 no.3
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• pp.309-319
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• 2011

We give sufficient conditions that the homogeneous differential equations : for $t{\geq}t_0$(> 0), $$x^{{\prime}{\prime}}(t)+q(t)x^{\prime}(t)+p(t)x(t)=0,\\x^{{\prime}{\prime}}(t)+q(t)x^{\prime}(t)+F(t,x({\phi}(t)))=0$$, are oscillatory where $0{\leq}{\phi}(t)$, 0 < ${\phi}^{\prime}(t)$, $\lim_{t\to{\infty}}{\phi}(t)={\infty}$. and $F(t,u){\cdot}sgn$ $u{\leq}p(t)|u|$. We obtain comparison theorems.

• Journal of the military operations research society of Korea
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• v.5 no.2
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• pp.27-38
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• 1979

This method explores a method of aggregating the measures of effectiveness of a weapon system from its characteristics. With this method, the constant sum method and multiple regression are used to develop a functional relationship between system effectiveness and system characteristics. As an example, a study of a tank weapon system was${\cdot}$conducted with data from the U.S. Army Armor School. It was concluded that the aggregation method is feasible, and that for the tank system studied, the reciprocals of system characteristics give a good estimating equation for measuring tank system effectiveness.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.13 no.3
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• pp.225-236
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• 2009

Image inpainting is the process of reconstructing lost or deteriorated parts of images using information from surrounding areas. We propose a computationally efficient and fast phase-field method which uses automatic switching parameter, adaptive time step, and automatic stopping of calculation. The algorithm is based on an energy functional. We demonstrate the performance of our new method and compare it with a previous method.