• The Bulletin of The Korean Astronomical Society
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• v.24 no.2
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• pp.73-73
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• 1999

• Bulletin of the Korean Space Science Society
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• 1999.09a
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• pp.65-65
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• 1999

No Abstract, See Full Text

• Bulletin of the Korean Mathematical Society
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• v.31 no.1
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• pp.105-113
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• 1994

In the course of study of dendroids, Czuba [3] introduced a notion of $R^{i}$ -continua which is a generalization of R-arc [1]. He showed a new class of non-contractible dendroids, namely of dendroids which contain an $R^{i}$ -continuum. Subsecequently Charatonik [2] attempted to extend the notion into hyperspace C(X) of metric continuum X. In so doing, there were some oversights in extending some of the results relating $R^{i}$ -continua of dendroids for metric continua. In fact, Proposition 1 in [2] is false (see example C below) and his proof of Theorem 6 in [2] is not correct (Take Example 4 in [4] with K = [e,e'] as an $R^{1}$-continuum of X and work it out. Then one seens that K not .mem. K as he claimed otherwise.). The aims of this paper are to introduce a notion of w-regular convergence which is weaker than 0-regular convergence and to prove that the w-regular convergence of a sequence {Xn}$^{\infty}$$_{n=1}$ to $X_{0}$ of subcontinua of a metric continuum X is a necessary and sufficient for the sequence {C( $X_{n}$)}$^{\infty}$$_{n=1}$ to converge to C( $X_{0}$ ), and also to prove that if a metric continuum X contains an $R^{i}$ -continuum with w-regular convergence, then the hyperspace C(X) of X contains $R^{i}$ -continuum.inuum.uum.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.8-13
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• 2007

2005년 남극의 해빙을 촬영한 Kompsat-1 EOC 영상을 이용하여 SSM/I와 AMSR-E 해빙 면적비를 비교， 분석하였다. EOC 영상은 남극의 봄철에 해당하는 9-11월 사이에 남극 대륙의 가장자리를 가로지르는 11 개 궤도로부터 총 676개 영상이 획득되었으며， 이 중 대기 및 광량 조건이 양호한 68개 의 영상을 선별하였다. EOC 영상에 감독분류 방볍 을 적 용하여 표면 유형 을 White ice(W), Grey ice(G), Dark-grey ice(D), Ocean(O)로 분류하였고 해빙 면적비를 산출하였으며, 이를 NASA Team Algorithm(NT)으로 계산된 SSM/I 해빙 면적비, NASA Team2 Algorithm(NT2)으로 계산된 AMSR-E 해빙 면적비와 비교하였다. 남극의 봄철에 SSM/I 해빙 면적비는 EOC W+G 면적비와 잘 일치하였고，AMSR-E 해빙 면적비는 EOC W+G+D 면적비와 좋은 상관성을 나타내었다. 따라서 이 시기의 남극 SSM/I NT 해빙 면적비는 W와 G만을 반영하며, AMSR-E NT2 해빙 면적비는 D도 포함하는 것을 알 수 있었다. 또한 AMSR-E가 SSM/I보다 높은 해빙 면적비를 나타내는 것을 확인하였으며，두 수동 마이크로파 해빙 면적비의 차이는 EOC D 면적비와 높은 상관성을 보였다. 이로부터 EOC 영상에서 분류된 D와 NT2에 서 고려되는 Ice type C가 서로 유사한 해빙 유형임을 추정할 수 있었다.

• Journal of Astronomy and Space Sciences
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• v.17 no.1
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• pp.39-44
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• 2000

We reinvestigate UV line emissions of 44i Boo, W UMa, AW UMa and VW Cep, which are indicaters of chromospheric activity of these stars. C I, C II, C IV, Si IV lines show significant variation in orbital phase. Among those lines, the Line of C IV showed the strongest line flux. while other Si IV and N V lines showed relative low line intensities. 44i Boo emitted the strongest flux than other stars. UV light curves of target stars shoed UV maximum at phase around 0.2 an 0.8 Such UV emissions are generally believed to be observed at the active regions and contacting parts of the two stars due to the clear visibility at the phase 0.2 and 0.8. Total emissivity of four transitions lines lead to conclude that the activity of this region is 40 times larger than the quiet sun. It is obvious that the activity decrease according to increase period. We obtained also Mg II light curve of AW UMA and VW Cep. These stars showed more clearly phase-dependent light curves. We estimated effective temperature of two star, AW UMa and VW Cep, using by Mg II flux.

• Korean Journal of Mathematics
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• v.19 no.1
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• pp.77-85
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• 2011

In [7], Th.M. Rassias proved that the norm defined over a real vector space V is induced by an inner product if and only if for a fixed integer $n{\geq}2$ $${\sum_{i=1}^{n}}\left\|x_i-{\frac{1}{n}}{\sum_{j=1}^{n}}x_j \right\|^2={\sum_{i=1}^{n}}{\parallel}x_i{\parallel}^2-n\left\|{\frac{1}{n}}{\sum_{i=1}^{n}}x_i \right\|^2$$ holds for all $x_1$, ${\cdots}$, $x_n{\in}V$. Let V, W be real vector spaces. It is shown that if an even mapping $f:V{\rightarrow}W$ satisfies $$(0.1)\;{\sum_{i=1}^{2n}f}\(x_i-{\frac{1}{2n}}{\sum_{j=1}^{2n}}x_j\)={\sum_{i=1}^{2n}}f(x_i)-2nf\({\frac{1}{2n}}{\sum_{i=1}^{2n}}x_i\)$$ for all $x_1$, ${\cdots}$, $x_{2n}{\in}V$, then the even mapping $f:V{\rightarrow}W$ is quadratic. Furthermore, we prove the generalized Hyers-Ulam stability of the quadratic functional equation (0.1) in Banach spaces.

• International Journal of Naval Architecture and Ocean Engineering
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• v.3 no.2
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• pp.150-158
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• 2011

Present study aims to investigate the influence of relative breakwater width W/L (W=width of breakwater, L=wavelength), wave steepness $H_i/gT^2$ (Hi=incident wave height, T=wave period) and relative wave height d/W (d=water depth) on forces in the moorings of horizontal interlaced multi-layered moored floating pipe breakwater (HIMMFPB) model. Studies were conducted on scaled down physical models having three layers of Poly Vinyl Chloride (PVC) pipes, wave steepness $H_i/gT^2$ varying from 0.063 to 0.849, relative width W/L varying from 0.4 to 2.65 and relative spacing S/D=2 (S=horizontal centre-to-centre spacing of pipes, D=diameter of pipes). Peak mooring forces were also measured and data collected is analyzed by plotting non-dimensional graphs depicting variation of $f_s/{\gamma}W^2$ ($f_s$=Sea side Mooring force, ${\gamma}$=specific weight of water) & $f_l/{\gamma}W^2$ ($f_l$=Lee side Mooring force) with $H_i/gT^2$ for d/W varying from 0.082 to 0.276 and also variation of $f_s/{\gamma}W^2$ and $f_l/{\gamma}W^2$ with W/L for $H_i$/d varying from 0.06 to 0.400.

• Kyungpook Mathematical Journal
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• v.59 no.4
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• pp.689-702
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• 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 $$c_{ij}=\left\{1{\text{ if }}i{\neq}j,\\0{\text{ if }}i=j.\right.$$.

• Journal of applied mathematics & informatics
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• v.39 no.3_4
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• pp.437-442
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• 2021

In this paper, we study the characterizations of two-sided best simultaneous approximations for ℓ-tuple subset from a closed convex subset of ℝ^m with ℓ^m₁(w)-norm. Main fact is, k^* is a two-sided best simultaneous approximation to F from K if and only if there exist f₁, …, f_p in F, for any k ∈ K $${\mid}{\sum\limits_{i=1}^{m}}sgn(f_{ji}-k^*_i)k_iw_i{\mid}{\leq}\;{\sum\limits_{i{\in}Z(f_j-k^*)}}\;{\mid}k_i{\mid}w_i$$ for each j = 1, …, p and 𝐰 ∈ W.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.949-954
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• 2012

The K-PCS and W-CDMA dual band dielectric duplexer and bandpass filters have been designed and fabricated. The dual band duplexer consists of the separate monoblock K-PCS and W-CDMA duplexers using common antenna port. The coupling capacitance and I/O impedance matching have been designed to minimize the cross interference between the bands. Isolations of crosspoint between Tx and Rx in K-PCS and W-CDMA dualband were about 47 dB and 100 dB, respectively. On the other hand, isolations of Tx and Rx in K-PCS and W-CDMA were about 66 dB and 65 dB, respectively. The difference between 47 dB and 100 dB originated from the different center frequencies in Tx and Rx of K-PCS and W-CDMA bands. The coupling capacitance of the bandwidth, I/O capacitance of I/O matching and impedance matching, and various capacitances were important role to fabricate the dielectric duplexer and bandpass filters.