• Kyungpook Mathematical Journal
• /
• v.59 no.4
• /
• pp.689-702
• /
• 2019

Let 𝓐 and 𝓑 be real (or complex) algebras. We investigate the stability of a sequence F = {f₀, f₁, ⋯, f_n, ⋯ } of mappings from 𝓐 into 𝓑 satisfying the higher functional equation: $$f_n(x+y+zw)=f_n(x)+f_n(y)+\;{\normalsize\sum\limits_{\tiny{i+j=n \atop i{\leq}j}}}\;[f_i(z)f_j(w)+c_{ij}f_i(w)f_j(z)]$$ for each n = 0, 1, ⋯ and all x, y, z, w ∈ 𝓐, where $$c_{ij}=\left\{1{\text{ if }}i{\neq}j,\\0{\text{ if }}i=j.\right.$$.

• Elastomers and Composites
• /
• v.55 no.4
• /
• pp.306-313
• /
• 2020

To investigate the reinforcing effects of functional fillers in nitrile rubber (NBR) materials, high-structure carbon black (HS45), coated calcium carbonate (C-CaCO3), silica (200MP), and multi-walled carbon nanotubes (MWCNTs) were used as functional filler, and carbon black (SRF) as a common filler were used for oil-resistant rubber. The curing and mechanical properties of HS45-, 200MP-, and MWCNT-filled NBR compounds were improved compared to those of the SRF-filled NBR compound. The reinforcing effect also increased with a decrease in the particle size of the fillers. The C-CaCO3-filled NBR compound exhibited no reinforcing effect with increasing filler concentration because of their large primary particle size (2 ㎛). The reinforcing behavior based on 100% modulus of the functional filler based NBR compounds was compared by using several predictive equation models. The reinforcing behavior of the C-CaCO3-filled NBR compound was in accordance with the Smallwood-Einstein equation whereas the 200MP- and MWCNT-filled NBR compounds fitted well with the modified Guth-Gold (m-Guth-Gold) equation. The SRF- and HS45-filled NBR compounds exhibited reinforcing behavior in accordance with the Guth-Gold and m-Guth-Gold equations, respectively, at a low filler content. However, the values of reinforcement parameter (100Mf/100Mu) of the SRF- and HS45-filled NBR compounds were higher than those determined by the predictive equation model at a high filler content. Because the chains of SRF composed of spherical filler particles are similarly changed to rod-like filler particles embedded in a rubber matrix and the reinforcement parameter rapidly increased with a high content of HS45, the higher-structured filler. The reinforcing effectiveness of the functional fillers was numerically evaluated on the basis of the effectiveness index (��SRF/��f) determined by the ratio of the volume fraction of the functional filler (��f) to that of the SRF filler (��SRF) at three unit of reinforcing parameter (100Mf/100Mu). On the basis of their effectiveness index, MWCNT-, 200MP-, and HS45-filled compounds showed higher reinforcing effectiveness of 420%, 70%, and 20% than that of SRF-filled compound, respectively whereas C-CaCO3-filled compound exhibited lower reinforcing effectiveness of -50% than that of SRF-filled compound.

• Communications of the Korean Mathematical Society
• /
• v.24 no.1
• /
• pp.29-40
• /
• 2009

Motivated by [Linear Algebra and its Appl. 420(2007), 218-227] and [Linear Algebra and its Appl. 425(2007), 171-183], we, in this paper, study the solvability of periodic boundary value problems of higher order nonlinear functional difference equations with p-Laplacian. Sufficient conditions for the existence of at least one solution of this problem are established.

• Communications of the Korean Mathematical Society
• /
• v.23 no.3
• /
• pp.387-399
• /
• 2008

We investigate approximately higher ternary derivations in Banach ternary algebras via the Cauchy functional equation $$f({\lambda}_{1x}+{\lambda}_{2y}+{\lambda}_{3z}={\lambda}_1f(x)+{\lambda}_2f(y)+{\lambda}_3f(z)$$.

• The Journal of Asian Finance, Economics and Business
• /
• v.4 no.3
• /
• pp.75-83
• /
• 2017

This paper examines key determinants and the effect of country-of-origin on customer's purchase intention of functional food and dietary supplement product in Vietnam. Exploratory study was identified to evaluate personal and social factors on customer's buying behavior. Twenty-eight reflective constructs were adapted from literature and designed by using a seven-point Likert scale to facilitate measurement. By using non-probability convenience sampling, data was collected from a survey of 242 Vietnamese who have experienced in buying functional and supplement food. This paper employed partial least square structural equation modeling (PLS-SEM) as a technique employed to analyze the measurement and structural models. The findings provide evidence that social prestige customer perceives and their positive attitude toward functional food which are main factors influencing on consumers' purchase intention. Customer's perceived prestige plays an important role in decision-making process to purchase. The higher social prestige taken up in consumers' mind, the higher consumers' purchase intention is. Moreover, the more positive attitude customer holds toward functional food, the higher consumers' purchase intention. The research results provide useful information in current understanding of what antecedents determine factors influencing customer's intention to purchase functional food and lead to managerial implications for business strategies.

• The Journal of Economics, Marketing and Management
• /
• v.11 no.4
• /
• pp.89-99
• /
• 2023

Purpose: This study explores the relationship between future time perspective and older consumers' masstige product consumption, specifically, their intention to purchase masstige brand products, with a focus on their motivational drives from an functional value and symbolic value perspective. Research design, data and methodology: Data were collected through an online questionnaire from 419 people aged 54 to 64 years in South Korea and the hypotheses were examined using structural equation modeling. Results: Our results indicated that middle-aged and older consumers who have expanded future time perspective have higher intention to purchase masstige brands and their functional value and symbolic value of masstige brands were found to mediate future time perspective and intention to purchase masstige brands. Conclusions: The findings offer insights into masstige brand consumption by older South Korean consumers that may be useful for both academics and marketers.

• Asia-Pacific Journal of Business
• /
• v.12 no.4
• /
• pp.1-12
• /
• 2021

Purpose - This study is an empirical study on the relationship of Thai consumers' attitude toward Korean Wave with the visit intention of Korean restaurants and a mediation effect of consumption value of Korean restaurants. Design/Methodology/Approach - Data were collected using a structured questionnaire of 245 Thai consumers and the hypotheses presented were verified by regression analysis and structural equation models. Findings - As a result of the empirical analysis, it was found that the higher the attractiveness and favorableness of Thai consumers for K-Wave, the higher the intention to visit Korean restaurants, and the Korean Wave attitude have a positive effect on the functional and symbolic values of Korean restaurants. In particular, the important result that can be presented in this study is that the better the attitude toward K-Wave, the higher the consumption value (functional/symbolic value) of Korean restaurants and the symbolic value plays a significant mediating effect on the relationship of the attitude of K-Wave and visiting intention, while the effect of functional value is not verified. Research Implication or Originality - These results means that in order to lead Thai consumers to a Korean restaurant using K-Wave, a strategy to make Thai ones perceive symbolic value of a Korean restaurant higher would be more effective. The main strategic implication of this study is that a high-end positioning strategy with a high symbolism, which make Korean restaurant as a suitable place as a means to show off one's value (or self) or as a means to show off one's social status (or role) to Thai consumers, will be relatively effective.

• Nonlinear Functional Analysis and Applications
• /
• v.29 no.1
• /
• pp.35-45
• /
• 2024

In this paper, we study the existence and multiplicity of nontrivial solutions for a p-Kirchhoff equation involving critical Sobolev-Hardy exponent by using variational methods and we need to estimate the energy levels.

• Journal of the Korean Society of School Health
• /
• v.24 no.2
• /
• pp.199-209
• /
• 2011

Purpose: The aim of this study was to investigate the structural relationships between functional deficiency of Family and self-esteem, depression, suicidal inclination of adolescents. Methods: The data in this study came from the Korea Youth Panel Survey Data (N=3,449) for 2005~2007. To investigate the causal relationship between each variable presented in the research model, structural equation modeling (SEM) was carried out by using AMOS 7.0. And all data were analyzed by using SPSS/WIN 12.0. Results: The main analytical results of this study were as follows; First, the family function made a positive impact on the self-esteem of adolescents. Second, the severe functional deficiency in family appeared to have a negative effect on the suicidal inclination and depression of adolescents. Third, the higher the adolescents' self-esteem, the lower depression and suicidal ideation. Fourth, the more severe the depression, the higher occurrence of suicidal inclination. Conclusion: In conclusion, functional deficiency in adolescents' family impacted negatively on self-esteem, and this contributed to increased depression and anxiety, and to suicidal inclination finally. These findings confirmed that the strength of family function, the closeness with parents, forming a stable relationship and strength of the emotional bond are very important factors to form self-esteem and reduce depression and suicidal inclination.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.1076-1082
• /
• 2003

As functional requirement of massive digital information storage devices are on a trend for the higher data transfer rate and lower cost, many different technical efforts are being tested and implemented in the industry. FDB(Fluid Dynamic Soaring) is one of the major breakthroughs in rotor design in terms of TMR budget. Although FDB analysis based on Reynolds' equation is well established and popularly being used for DB design especially for the estimation of bearing stiffness, there are obvious limitations in the approach due to the inherent assumptions. A generalized analysis tool employing the full Navier-Stokes equation and the energy balance is to be beneficial for detailed FDB design In this publication, an efficient geometry modeling method is presented that provides fully integrated inputs for general FVM/FDM codes. By virtue of the flexibility of the presented method, many different detailed FDB design and analysis are carried over with ease.