• Journal of applied mathematics & informatics
• /
• v.34 no.5_6
• /
• pp.509-517
• /
• 2016

In this paper, we consider the following functional equation with involution f(x + y) + f(x + σ(y)) = 2f(x) + f(y) + f(σ(y)) and prove the generalized Hyers-Ulam stability for it when the target space is a non-Archimedean Banach space.

• The Bulletin of The Korean Astronomical Society
• /
• v.36 no.2
• /
• pp.81.1-81.1
• /
• 2011

The new coherent scatter ionospheric radar has been operating at Gyerong city ($36.18^{\circ}N$, $127.14^{\circ}E$, dip lat $26.7^{\circ}N$), South Korea. This VHF radar is consisted of 24 Yagi antennas having 5 elements and observes the E- and F-region field-aligned irregularities (FAIs) in a single frequency of 40.8 MHz with a peak power of 24 kW. We present the first results of the E- and F-region FAIs over Korea by using the new VHF coherent scatter ionospheric radar. The morphological and echo characteristics are studied in terms of their echo strength, Doppler velocity and also by spectral width values. From the continuous observations from December 2009, we found ionospheric E- and F-region FAIs appeared frequently. The most interesting and striking observations for E region are occurrence of daytime E-region irregularities and strong Quasi-Periodic (QP) echoes at nighttime. And for F region, strong post-sunset and pre-sunrise FAIs appeared frequently. The VHF radar observations over Korea are discussed in the light of current understanding of mid-latitude E- and F-region FAIs.

• Communications of the Korean Mathematical Society
• /
• v.14 no.1
• /
• pp.201-210
• /
• 1999

We introduce the notion of the Finsler metrics compatible with f(5,1)-structure and investigate the properties of Finsler space with such metrics.

• Kyungpook Mathematical Journal
• /
• v.54 no.2
• /
• pp.203-209
• /
• 2014

We assume that the existence and termination conjecture for flips holds. A complex projective manifold is said to be of almost general type if the intersection number of the canonical divisor with every very general curve is strictly positive. Let f be an algebraic fiber space from X to Y. Then the manifold X is of almost general type if every very general fiber F and the base space Y of f are of almost general type.

• Journal of applied mathematics & informatics
• /
• v.16 no.1_2
• /
• pp.461-468
• /
• 2004

Let W(z) be a power series with operator coefficients such that multiplication by W(z) is contractive in C(z). The overlapping space $L(\varphi)$ of H(W) in C(z) is a Herglotz space with Herglotz function $\varphi(z)$ which satisfies $\varphi(z)+\varphi^＊(z^{-1})=2[1-W^{*}(z^{-1})W(z)]$. The identity ${}_{L(\varphi)}={-}_{H(W)}$ holds for every f(z) in $L(\varphi)$ and for every vector c.

• Korean Institute of Interior Design Journal
• /
• v.21 no.5
• /
• pp.298-307
• /
• 2012

Contemporary design of food and beverage(F&B) space reflects various needs, not only of eating, but also environmental ones. As a way of meeting this conceptual change and the various needs of contemporary consumers, kitsch expression is often utilized actively. Thus, this study intends to analyze the design characteristics and methods of kitsch expression found in contemporary F&B space and their correlations with sensitivity factors, focusing on relevant cases. Specifically, it examined the definition, origin, and changes of kitsch, and identified the sensitive role of kitsch in interior space. Next, it classified the kitsch characteristics and design methods found in interior design, finally analyzing the characteristics of kitsch expressions in contemporary F&B space by sensitivity factors and their correlations with design methods. As a consequence, it was found that the attempts in contemporary F&B space design to differentiate space through active introduction of various kitsch expressions were fulfilling the sensitive needs of changing consumers by providing new cultural experiences. That is, such attempts are considered to have improved the satisfaction of consumers who value sensitivity, by means of wide exchange of sensitivity between designers and consumers. To raise the sensitive satisfaction of consumers more in future, it is necessary to further continuous and in-depth research on the correlation between kitsch expressions and sensitivity factors in interior design.

• Journal of the Chungcheong Mathematical Society
• /
• v.26 no.2
• /
• pp.427-433
• /
• 2013

Observing that every Tychonoff space X has an extension $kX$ which is a weakly Lindel$\ddot{o}$f space and the minimal quasi-F cover $QF(kX)$ of $kX$ is a weakly Lindel$\ddot{o}$f, we show that ${\Phi}_{kX}:QF(kX){\rightarrow}kX$ is a $z^{\sharp}$-irreducible map and that $QF({\beta}X)=QF(kX)$. Using these, we prove that $QF(kX)=kQF(X)$ if and only if ${\Phi}^k_X:kQF(X){\rightarrow}kX$ is an onto map and ${\beta}QF(X)=(QF{\beta}X)$.

• Honam Mathematical Journal
• /
• v.6 no.1
• /
• pp.1-12
• /
• 1984

Let(X, $\Im$) be a probabilistic metric space with a t-norm. Common fixed point theorems and convergence theorems generalizing the results of Ćirić, Fisher, Sehgal, Istrătescu-Săcuiu and others are proved for three mappings P,S,T on X satisfying $F_{Pu, Pv}(qx){\geq}min\left{F_{Su,Tv}(x),F_{Pu,Su}(x),F_{Pv,Tv}(x),F_{Pu,Tv}(2x),F_{Pv,Su}(2x)\right}$ for every $u, v {\in}X$, all x>0 and some $q{\in}(0, 1)$. One of the main results is extended to uniform spaces. Mathematics Subject Classification (1980): 54H25.

• Bulletin of the Korean Mathematical Society
• /
• v.48 no.4
• /
• pp.779-789
• /
• 2011

In this paper we study the Banach space $L^1$(G) of real valued measurable functions which are integrable with respect to a vector measure G in the sense of D. R. Lewis. First, we investigate conditions for a scalarly integrable function f which guarantee $f{\in}L^1$(G). Next, we give a sufficient condition for a sequence to converge in $L^1$(G). Moreover, for two vector measures F and G with values in the same Banach space, when F can be written as the integral of a function $f{\in}L^1$(G), we show that certain properties of G are inherited to F; for instance, relative compactness or convexity of the range of vector measure. Finally, we give some examples of $L^1$(G) related to the approximation property.

• Journal of the Korean Mathematical Society
• /
• v.32 no.2
• /
• pp.279-287
• /
• 1995

Let $F$ be a set of distributions on R with the topology of weak convergence, and let $A$ be the $\sigma$-field generated by the open sets. We denote by $F_1^\infty$ the space consisting of all infinite sequence $(F_1, F_2, \cdots), F_n \in F and R_1^\infty$ the space consisting of all infinite sequences $(x_1, x_2, \cdots)$ of real numbers. Take the $\sigma$-field $F_1^\infty$ to be the smallest $\sigma$-field of subsets of $F_1^\infty$ containing all finite-dimensional rectangles and take $B_1^\infty$ to be the Borel $\sigma$-field $R_1^\infty$.