• Bulletin of the Korean Mathematical Society
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• v.60 no.1
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• pp.75-81
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• 2023

If a multiplicative function f is commutable with a quadratic form x² + xy + y², i.e., f(x² + xy + y²) = f(x)² + f(x) f(y) + f(y)², then f is the identity function. In other hand, if f is commutable with a quadratic form x² - xy + y², then f is one of three kinds of functions: the identity function, the constant function, and an indicator function for ℕ ＼ pℕ with a prime p.

• Bulletin of the Korean Mathematical Society
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• v.34 no.2
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• pp.155-171
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• 1997

Let $M^n$ be a connected subminifold of a Euclidean space $E^m$, equipped with the induced metric. Denoty by $\Delta$ the Laplacian operator of $M^n$ and by x the position vector. A well-known T. Takahashi's theorem [13] says that $\delta x = \lambda x$ for some constant $\lambda$ if and only if $M^n$ is either minimal subminifold of $E^m$ or minimal submanifold in a hypersphere of $E^m$. In [9], O. Garay studied the hypersurfaces $M^n$ in $E^{n+1}$ satisfying $\delta x = Dx$, where D is a diagonal matrix, and he classified such hypersurfaces. Garay's condition can be seen as a generalization of T.

• Communications of the Korean Mathematical Society
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• v.22 no.1
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• pp.65-74
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• 2007

Suppose that $\mu$ is a finite positive Borel measure on bounded symmetric domain $\Omega{\subset}\mathbb{C}^n\;and\;\nu$ is the Euclidean volume measure such that $\nu(\Omega)=1$. Suppose 1 < p < $\infty$ and r > 0. In this paper, we will show that the norms $sup\{\int_\Omega{\mid}k_z(w)\mid^2d\mu(w)\;:\;z\in\Omega\}$, $sup\{\int_\Omega{\mid}h(w)\mid^pd\mu(w)/\int_\Omega{\mid}h(w)^pd\nu(w)\;:\;h{\in}L_a^p(\Omega,d\nu),\;h\neq0\}$ and $$sup\{\frac{\mu(E(z,r))}{\nu(E(z,r))}\;:\;z\in\Omega\}$$ are are all equivalent. We will also show that the inclusion mapping $ip\;:\;L_a^p(\Omega,d\nu){\rightarrow}L^p(\Omega,d\mu)$ is compact if and only if lim $w\rightarrow\partial\Omega\frac{\mu(E(w,r))}{\nu(E(w,r))}=0$.

• Journal of the Chungcheong Mathematical Society
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• v.33 no.2
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• pp.227-236
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• 2020

A set {a₁, a₂,_…, a_m} of positive integers is called Diophantine m-tuple if a_ia_j+1 is a perfect square for all 1 ≤ i < j ≤ m. In this paper, we find the structure of torsion group of elliptic curve E_k constructed by Diophantine triple, and find all integer points on E_k under assumption that rank(E_k(ℚ)) = 1.

• CRM연구
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• v.2 no.2
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• pp.71-88
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• 2009

The purpose of this thesis is to examine the effects of e-CRM activities by the internet shopping mall companies on the purchase activities of purchase customers and the potential customers. The internet shopping companies utilize e-CRM to systematically identify customers' varying demands, and to utilize the results as marketing tools, thus producing a significant effect on the potential customers by generating customer feedback through e-Community. Contrary to their intention, however, cognitive dissonance can occur through e-Community, which may lead to customers' complaints. If these complaints are not properly managed and settled in a timely manner, they can be transferred to other potential customers, and the conformity phenomenon could be created by other complaining customers. Findings obtained through this thesis are as follows: If cognitive disharmony is created by customers who purchased products through the internet shopping malls, this can lead to private complaining behaviors, and subsequently, these behaviors are formed through e-Community. If the internet shopping mall companies do not take any timely and proper measures to intervene in the stage of private complaining behaviors in the first place, these behaviors will immediately escalate into the public complaining behaviors. Furthermore, the complaints will be transferred to other potential customers, ultimately resulting in their swift expansion. In other words, contrary to intention of the internet shopping mall companies, e-CRM does not facilitate the potential customers purchase decision, it rather affects them to postpone or withdraw their purchase decision. Accordingly, the internet shopping mall companies are required to manage e-Community with extreme care, and they should promptly respond to the complaining customers so that e-Community can function properly.

• Journal of Information Technology Applications and Management
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• v.22 no.2
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• pp.219-230
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• 2015

Recently, electronic-book (e-book) market is growing rapidly due to the evolution of information technology and e-book standard EPUB. Users can search e-book on-line and download easily to their e-book readers such as amazon's kindle or smartphones. On the other hand, there is lack of e-book contents for the reading disabled people because of high cost of making e-book accessibility for the reading disabled people. If we can translate EPUB specified e-book contents to the alternative e-book contents suitable for the reading disabled people, then there are many advantages to acquire various types and large volumes of e-book contents for the reading disabled people. This paper suggests a new electronic publishing ecosystem for the reading disabled people using e-book translation method. It also suggests a promotion strategy of e-book market for the reading disabled people.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.136-160
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• 2002

Most important to financial institutions is to provide well designed and built services to the customers by accessing their core bank systems and affiliated systems in their partners. This will be essential to introduce new products and services and still be able to count on legacy and collaborative affiliated systems. Winning the war on such service competitions among financial institutions is attainable by seizing the "e-bank" opportunities in B2Bi and CRM (Customer Relationship Management). Such application integrations among systems and "e-bank" services need to be available in the new IT environment. In this article, an If and service architecture adopting unified e-business services platform is proposed. This architecture is able to achieve application integrations among legacy, affiliated, and e-business systems and services. We derive an architecture in unified e-business services platform by investigating current and future e-business services platforms involved in domestic and global international banks. Several financial interchange standards which are involved in B2B business of e-procurement, e-placement, e-payment are also investigated.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.2
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• pp.157-163
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• 2014

Let {$X_i$, $1{\leq}i{\leq}n$} be a sequence of i.i.d. sequence of positive random variables with common absolutely continuous cumulative distribution function F(x) and probability density function f(x) and $E(X^2)$ < ${\infty}$. The random variables X + Y and $\frac{(X-Y)^2}{(X+Y)^2}$ are independent if and only if X and Y have gamma distributions. In addition, the random variables $S_n$ and $\frac{\sum_{i=1}^{m}(X_i)^2}{(S_n)^2}$ with $S_n=\sum_{i=1}^{n}X_i$ are independent for $1{\leq}m$ < n if and only if $X_i$ has gamma distribution for $i=1,{\cdots},n$.

• Journal of applied mathematics & informatics
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• v.32 no.1_2
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• pp.55-60
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• 2014

In this paper, we will obtain Marcinkiewicz's type limit laws for fuzzy random sets as follows : Let {$X_n{\mid}n{\geq}1$} be a sequence of independent identically distributed fuzzy random sets and $E{\parallel}X_i{\parallel}^r_{{\rho_p}}$ < ${\infty}$ with $1{\leq}r{\leq}2$. Then the following are equivalent: $S_n/n^{\frac{1}{r}}{\rightarrow}{\tilde{0}}$ a.s. in the metric ${\rho}_p$ if and only if $S_n/n^{\frac{1}{r}}{\rightarrow}{\tilde{0}}$ in probability in the metric ${\rho}_p$ if and only if $S_n/n^{\frac{1}{r}}{\rightarrow}{\tilde{0}}$ in $L_1$ if and only if $S_n/n^{\frac{1}{r}}{\rightarrow}{\tilde{0}}$ in $L_r$ where $S_n={\Sigma}^n_{i=1}\;X_i$.

• Animal Bioscience
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• v.35 no.1
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• pp.105-114
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• 2022

Objective: This work was carried out to evaluate the effect of pasture (PA) feeding on buffalo meat quality compared with buffaloes reared intensively with the use of corn silage as a forage base or alternatively with polyphite meadow hay (PH). Methods: Thirty Mediterranean bull buffaloes were distributed into three experimental diet groups: maize silage (MS), PH, and PA. The animals were slaughtered at a live weight of 250 kg, and carcass and meat quality were evaluated. After 7 days of ageing, physical and chemical parameters of longissimus thoracis muscle were determined. To evaluate lipid oxidation the thiobarbituric acid reactive substances was tested at 7 and 14 days, and also the fatty acid profile was recorded by gas chromatography. Results: The PA group, even if it showed carcass parameters lower than those of the silage maize group, reported a good meat percentage (60.59% vs 58.46%, respectively) and lower fat percentage (p<0.001). PA-fed animals showed meat redness, and even if only on raw meat, shear force was higher than the others. Low values of conjugate linoleic acid, polyunsaturated fatty acids, and n-3 were reported in the silage maize group. Principal component analysis (PCA) clearly showed the influence of different diets on meat quality, and PCA1 and PCA2 explained 82% of the variability. Conclusion: Buffaloes reared on PA had meat with high nutritional value even if they showed poor carcass performance compared to the animals fed on MS. Buffaloes fed on polyphite hay were in an intermediate position, similar to grazing animals, according to the same nutritional determinations.