• 한국인터넷방송통신학회논문지
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• 제19권2호
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• pp.73-77
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• 2019

본 논문에서는 이동형 위성단말에서 발생하는 shadowing 채널에 ARQ 기술을 적용하여 성능을 확인한다. shadowing은 위성단말이 이동하면서 생기는 신호 단절이다. 신호 단절을 보상하기 위해 신호를 재전송하는 ARQ기술을 사용할 수 있다. 위성통신에서는 송신 데이터와 ack채널에서 shadowing이 발생한다. 두 채널에서 발생하는 shadowing의 상관관계에 따라 ARQ 기술 적용 후 예상되는 전송량은 다르다. 따라서 shadowing채널에 ARQ 기술을 적용할 경우 예상되는 성능을 확인한다. 분석결과 단말이 송신할 경우와 수신할 경우 전송량의 차이를 보였고, 수식적으로 성능을 예측할 수 있음을 보였다.

• 대한수학회논문집
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• 제21권3호
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• pp.515-526
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• 2006

In this paper, we give a characterization of hyperbolic linear dynamical systems via the notions of various inverse shadowing. More precisely it is proved that for a linear dynamical system f(x)=Ax of ${\mathbb{C}^n}$, f has the ${\tau}_h$ inverse(${\tau}_h-orbital$ inverse or ${\tau}_h-weak$ inverse) shadowing property if and only if the matrix A is hyperbolic.

• Journal of applied mathematics & informatics
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• 제38권3_4호
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• pp.249-254
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• 2020

Here, assume that X is a compact space. we show that if f is a locally nonexpansive map then f : X → X has the limit shadowing property if and only if f : CR(f) → CR(f) has the limit shadowing property. Also we prove that if f is a local expansion then f has the limit shadowing property.

• 충청수학회지
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• 제34권1호
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• pp.55-60
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• 2021

In this paper we deal with the preservation of the periodic shadowing property of induced hyperspatial systems. More precisely, we show that an expansive system has the periodic shadowing property if and only if its induced hyperspatial system has the periodic shadowing property.

• 대한수학회지
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• 제56권1호
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• pp.53-65
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• 2019

Recently, Chung and Lee [2] introduced the notion of topological stability for a finitely generated group action, and proved a group action version of the Walters's stability theorem. In this paper, we introduce the concepts of continuous shadowing and continuous inverse shadowing of a finitely generated group action on a compact metric space X with respect to various classes of admissible pseudo orbits and study the relationships between topological stability and continuous shadowing and continuous inverse shadowing property of group actions. Moreover, we introduce the notion of structural stability for a finitely generated group action, and we prove that an expansive action on a compact manifold is structurally stable if and only if it is continuous inverse shadowing.

• 충청수학회지
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• 제28권3호
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• pp.483-489
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• 2015

In this paper we introduce two notions of measure shadowing for homeomorphsims, and study the relationship between them.

• 대한수학회논문집
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• 제21권2호
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• pp.355-361
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• 2006

We prove that if a continuous surjective map f on a compact metric space X has the average shadowing property, then every point x is chain recurrent. We also show that if a homeomorphism f has more than two fixed points on $S^1$, then f does not satisfy the average shadowing property. Moreover, we construct a homeomorphism on a circle which satisfies the shadowing property but not the average shadowing property. This shows that the converse of the theorem 1.1 in [6] is not true.

• Kyungpook Mathematical Journal
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• 제49권3호
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• pp.411-418
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• 2009

In this paper we introduce the notions of strict persistence and weakly strict persistence which are stronger than those of persistence and weak persistence, respectively, and study their relations with shadowing property. In particular, we show that the weakly strict persistence and the weak inverse shadowing property are locally generic in Z(M).

• 대한수학회보
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• 제51권1호
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• pp.67-76
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• 2014

Let X be a divergence-free vector field defined on a closed, connected Riemannian manifold. In this paper, we show the equivalence between the following conditions: ${\bullet}$ X is a divergence-free vector field satisfying the shadowing property. ${\bullet}$ X is a divergence-free vector field satisfying the Lipschitz shadowing property. ${\bullet}$ X is an expansive divergence-free vector field. ${\bullet}$ X has no singularities and is Anosov.

• 대한수학회지
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• 제45권6호
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• pp.1505-1521
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• 2008

In this paper, we give a characterization of the structurally stable vector fields via the notion of orbital inverse shadowing. More precisely, it is proved that the $C^1$ interior of the set of $C^1$ vector fields with the orbital inverse shadowing property coincides with the set of structurally stable vector fields. This fact improves the main result obtained by K. Moriyasu et al. in [15].