• 한국수학교육학회지시리즈B:순수및응용수학
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• 제22권2호
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• pp.185-197
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• 2015

The author considers a Noor-type iterative scheme to approximate com- mon fixed points of an infinite family of uniformly quasi-sup(f_n)-Lipschitzian map- pings and an infinite family of g_n-expansive mappings in convex cone metric spaces. His results generalize, improve and unify some corresponding results in convex met- ric spaces [1, 3, 9, 16, 18, 19] and convex cone metric spaces [8].

• 대한수학회보
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• 제56권5호
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• pp.1315-1325
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• 2019

The purpose of this article is to study the Ricci solitons and Ricci almost solitons on para-Kenmotsu manifold. First, we prove that if a para-Kenmotsu metric represents a Ricci soliton with the soliton vector field V is contact, then it is Einstein and the soliton is shrinking. Next, we prove that if a ${\eta}$-Einstein para-Kenmotsu metric represents a Ricci soliton, then it is Einstein with constant scalar curvature and the soliton is shrinking. Further, we prove that if a para-Kenmotsu metric represents a gradient Ricci almost soliton, then it is ${\eta}$-Einstein. This result is also hold for Ricci almost soliton if the potential vector field V is pointwise collinear with the Reeb vector field ${\xi}$.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제28권3호
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• pp.253-266
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• 2021

In this paper, we generalize the notion of comparable set-valued mappings by introducing two types of 𝓡-closed set-valued mappings and utilize these to obtain an analogue of celebrated Mizoguchi and Takahashi fixed point theorem in relational metric spaces. To annotate the claims and usefulness of such findings, we prove fixed point results for both set-valued and single-valued mappings and validate the assertions with the help of examples. In this way, these investigations extend, modify and generalize some prominent recent fixed point results obtained by Tiammee and Suantai [24], Amini-Harandi and Emami [4], Prasad and Dimri [19] and several others in the settings of relational metric spaces.

• 대한수학회보
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• 제61권3호
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• pp.867-873
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• 2024

A pseudo-Riemannian solvmanifold is a solvable Lie group endowed with a left invariant pseudo-Riemannian metric. In this short note, we investigate the nilpotency of the Ricci operator of pseudo-Riemannian solvmanifolds. We focus on a special class of solvable Lie groups whose Lie algebras can be expressed as a one-dimensional extension of a nilpotent Lie algebra ℝD⋉n, where D is a derivation of n whose restriction to the center of n has at least one real eigenvalue. The main result asserts that every solvable Lie group belonging to this special class admits a left invariant pseudo-Riemannian metric with nilpotent Ricci operator. As an application, we obtain a complete classification of three-dimensional solvable Lie groups which admit a left invariant pseudo-Riemannian metric with nilpotent Ricci operator.

• 한국통신학회논문지
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• 제34권1B호
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• pp.16-23
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• 2009

이 논문은 멀티 홉 무선 메쉬 네트워크에서 제공하는 라우팅 프로토콜이 적용된 라우팅 metric에 따라 최적의 경로를 얼마나 잘 찾는가에 관한 논문이다. 최근에 제시된 라우팅 metric은 Link Quality (LQ)를 정확히 나타내도록 설계되어있지만, 많은 metric들은 그것을 기반으로 찾은 경로들이 얼마나 많은 비율로 최적의 경로를 찾을 수 있는지에 대해서 검증하지 않았다. 우리는 최근에 잘 디자인된 라우팅 metric들과 가장 많이 사용되는 라우팅 프로토콜의 다양한 조합을 고려하였다. 그리고 각각의 라우팅에서 찾은 경로의 최적 정도를 살펴보았습니다. 또한 무선 링크의 비대칭성을 반영한 metric을 위해서 단 방향성을 가지는 라우팅 프로토콜을 제안한다. 시뮬레이션을 통해서 만들어진 최적 경로의 비율이 살펴본 모든 라우팅 metric 및 프로토콜 그리고 네트워크 구조에 대해서 네트웍 트래픽 양에 따라 감소하는 현상을 알 수 있다.

• 대한수학회지
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• 제33권3호
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• pp.625-639
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• 1996

A convex $RP^n$-structure on a smooth anifold M is a representation of M as a quotient of a convex domain $\Omega \subset RP^n$ by a discrete group $\Gamma$ of collineations of $RP^n$ acting properly on $\Omega$. When M is a closed surface of genus g > 1, then the equivalence classes of such structures form a moduli space $B(M)$ homeomorphic to an open cell of dimension 16(g-1) (Goldman [2]). This cell contains the Teichmuller space $T(M)$ of M and it is of interest to know what of the rich geometric structure extends to $B(M)$. In [3], a symplectic structure on $B(M)$ is defined, which extends the symplectic structure on $T(M)$ defined by the Weil-Petersson Kahler form.

• Korean Journal of Mathematics
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• 제32권3호
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• pp.561-591
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• 2024

In this article, we demonstrate the conditions for the existence of common fixed points (CFP) theorems for four self-maps satisfying the common limit range (CLR)-property on cone b-normed spaces (CbNS) via ℭ-class functions. Furthermore, we have a unique common fixed point for two weakly compatible (WC) pairings. Towards the end, the existence and uniqueness of common solutions for systems of functional equations arising in dynamic programming are discussed as an application of our main result.

• 한국항행학회논문지
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• 제24권1호
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• pp.28-36
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• 2020

KASS(Korea Augmentation Satellite System)는 국토교통부에서 2014년부터 개발 중인 한국형 위성항법보강시스템이다. KASS는 항공기 안전에 영향을 미칠수 있는 항공용 시스템이기 때문에 KASS의 각 소프트웨어는 안전성 분석을 통해 할당된 DO-178B의 소프트웨어 레벨에 따라 개발이 수행된다. KASS의 하위시스템인 통합운영국의 경우 일부 소프트웨어를 제외하고는 DO-178B 레벨E를 할당 받았으며 DO-178B 레벨E 소프트웨어의 경우 제품 보증을 위해 ECSS-Q-ST-80C 카테고리 D를 준수하여 개발하도록 하고 있다. 본 논문에서는 ECSS-Q-ST-80C를 만족하기 위해 ECSS-E-ST-40C, ECSS-Q-HB-80-04A를 분석하여 KASS 통합운영국 소프트웨어의 제품 보증을 위한 소프트웨어 생명 주기 별 활동 및 소프트웨어 품질 모델, 메트릭을 제안한다.

• 호남수학학술지
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• 제5권1호
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• pp.139-149
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• 1983

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제26권4호
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• pp.277-288
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• 2019

The main objective of this article is to establish some coincidence point theorem for g-non-decreasing mappings under contraction mapping principle on a partially ordered metric space. Furthermore, we constitute multidimensional results as a simple consequences of our unidimensional coincidence point theorem. Our results improve and generalize various known results.