• Journal of information and communication convergence engineering
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• 제21권2호
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• pp.103-109
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• 2023

We investigated the antipodal-symmetric dispersion maps of a dispersion-managed link with a midway optical phase conjugator to compensate for the distorted 960 Gb/s wavelength division multiplexed (WDM) signal caused by these effects. The proposed antipodal-symmetric dispersion map has various shapes depending on the detailed design scheme. We confirmed that the dispersion-managed link designed with the dispersion map of the antipodal-symmetric structure is more advantageous than the conventional uniform dispersion map for compensating WDM channels. It was also confirmed that among the antipodal-symmetric structures, the dispersion map configured with the S-1-profile, in which S is inverted up and down, was more effective for distortion compensation than the dispersion map configured with the S-profile. In particular, we confirmed that the S-1-profile can broaden the optical pulse width intensively at a short transmission distance, more effectively compensating for the distorted WDM channel. Because this structure makes the intensity of the optical pulse relatively weak, it can decrease the nonlinear Kerr effect.

• 대한수학회보
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• 제53권5호
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• pp.1309-1325
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• 2016

This note focuses on a ring property in which upper and lower nilradicals coincide, as a generalizations of symmetric rings. The concept of symmetric ideal and ring in the noncommutative ring theory was initially introduced by Lambek, as an extension of the usual commutative ideal theory. The investigation of symmetric rings provided many useful results to the study in the noncommutative ring theory. So the results obtained from this study may be applicable to observing the structure of zero divisors in various kinds of algebraic systems containing matrix rings and polynomial rings.

• 한국정보통신학회논문지
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• 제15권4호
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• pp.860-868
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• 2011

블록 암호는 Feistel 구조와 SPN 구조로 나눌 수 있다. Feistel 구조는 암호 및 복호 알고리즘이 같은 구조이고, SPN 구조는 암호 및 복호 알고리즘이 다르다. 본 논문에서는 암호와 복호 과정이 동일한 SPN 구조 블록 암호 알고리즘인 가칭 SSB를 제안한다. SSB는 짝수 N 라운드로 구성하고, 각 라운드는 라운드 키 덧셈, 치환 계층, 바이트 교환 및 확산 계층으로 구성한다. 치환 계층은 홀수 라운드와 짝수 라운드가 서로 역의 관계를 이룬다. 확산 계층은 MDS 대합 행렬로 구성한다. SSB의 차분 및 선형 공격 확률은 $2^{-306}$로 AES와 동일하다. 본 논문에서 제안한 암호와 복호가 동일한 SPN 블럭 암호는 하드웨어 구성이 간단한 장점을 가지므로 제한적 하드웨어 및 소프트웨어 환경인 스마트카드와 전자 칩이 내장된 태그와 같은 RFID 환경에서 안전하고 효율적인 암호 시스템을 구성할 수 있다.

• 대한수학회논문집
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• 제29권2호
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• pp.311-317
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• 2014

We study lightlike hypersurfaces of a semi-Riemannian space form $\tilde{M}(c)$ admitting a semi-symmetric non-metric connection. First, we construct a type of lightlike hypersurfaces according to the form of the structure vector field of $\tilde{M}(c)$, which is called a ascreen lightlike hypersurface. Next, we prove a characterization theorem for such an ascreen lightlike hypersurface endow with a totally geodesic screen distribution.

• 대한수학회논문집
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• 제35권1호
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• pp.251-260
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• 2020

In this paper, we show that it is Chen surfaces that non-minimal pseudo-Hermitian mass-symmetric 2-type Legendre surfaces in S⁵. Moreover, we show that pseudo-Hermitian mass-symmetric 2-type Legendre surfaces in S⁵ are the locally product of two pseudo-Hermitian circles.

• 대한수학회보
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• 제41권2호
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• pp.359-369
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• 2004

The purpose of this paper is to compare the radicals of a left symmetric algebra considered in 〔1〕 when the associated Lie algebra is nilpotent. In this case, we show that all the radicals considered there are equal. We also consider some other radicals and show they are also equal.

• 대한수학회지
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• 제43권6호
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• pp.1301-1324
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• 2006

The affine homogeneous hypersurface in ${\mathbb{R}}^{n+1}$, which is a graph of a function $F:{\mathbb{R}}^n{\rightarrow}{\mathbb{R}}$ with |det DdF|=1, corresponds to a complete unimodular left symmetric algebra with a nondegenerate Hessian type inner product. We will investigate the condition for the domain over the homogeneous hypersurface to be homogeneous through an extension of the complete unimodular left symmetric algebra, which is called the graph extension.

• Journal of applied mathematics & informatics
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• 제16권1_2호
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• pp.453-459
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• 2004

A left-invariant flat Riemannian connection on a Lie group makes its Lie algebra a left symmetric algebra compatible with an inner product. The left symmetric algebra is decomposed into trivial ideal and a subalgebra of e(l). Using this result, the Lie group is embedded isomorphically into the direct product of O(l) $\times$ $R^{k}$ for some nonnegative integers l and k.

• East Asian mathematical journal
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• 제31권3호
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• pp.337-344
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• 2015

We study screen quasi-conformal irrotational half lightlike submanifolds M of a semi-Riemannian space form $\bar{M}$ (c) equipped with a semi-symmetric non-metric connection subject such that the structure vector field of $\bar{M}$ (c) belongs to the screen distribution S(TM). The main result is a non-existence theorem for such half lightlike submanifolds.

• Bulletin of the Korean Chemical Society
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• 제27권4호
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• pp.515-518
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• 2006

It is explicitly shown that a supersymmetry structure exists in the spectrum of a rigid symmetric top rotor in the molecule-fixed frame. Using projection operators constructed from the time-reversal symmetry of the rotor, the full rotor Hamiltonian is separated into two parts, i.e., the bosonic and fermionic components. The construction, without ambiguity, suggests that the rotor has a supersymmetry in it. This supersymmetry is mathematically equivalent to that of the free rotor on a plane recently noted by Rau.