• 대한수학회논문집
• /
• 제34권3호
• /
• pp.981-989
• /
• 2019

In this paper we deal with some shadowing properties of discrete dynamical systems on a compact metric space via the density of subdynamical systems. Let $f:X{\rightarrow}X$ be a continuous map of a compact metric space X and A be an f-invariant dense subspace of X. We show that if $f{\mid}_A:A{\rightarrow}A$ has the periodic shadowing property, then f has the periodic shadowing property. Also, we show that f has the finite average shadowing property if and only if $f{\mid}_A$ has the finite average shadowing property.

• Journal of applied mathematics & informatics
• /
• 제40권1_2호
• /
• pp.185-190
• /
• 2022

The aim of this article is to define fuzzy maximal open cover and discuss its few properties. we also defined and study fuzzy m-compact space and discussed its properties. Also we obtain few more results on fuzzy minimal c-regular and fuzzy minimal c-normal spaces. We have proved that a fuzzy Haussdorff m-compact space is fuzzy minimal c-normal.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 2003년도 춘계 학술대회 학술발표 논문집
• /
• pp.41-44
• /
• 2003

First, we investigate some properties of fuzzy compactness. Second, we introduce the concept of fuzzy local compactness in fuzzy topological space and study some of its properties. Finally, we investigate some relations between F-compactness in fuzzy topological spaces and one in fuzzy hyperspaces.

• Journal of Astronomy and Space Sciences
• /
• 제27권4호
• /
• pp.353-357
• /
• 2010

In general, the information of inertia properties is required to control a spacecraft. The inertia properties are changed by some activities such as consumption of propellant, deployment of solar panel, sloshing, etc. Extensive estimation methods have been investigated to obtain the precise inertia properties. The gyro-based attitude data including noise and bias needs to be compensated for improvement of attitude control accuracy. A modified estimation method based on the law of conservation of angular momentum is suggested to avoid inconvenience like filtering process for noise-effect compensation. The conventional method is modified and beforehand estimated moment of inertia is applied to improve estimation efficiency of product of inertia. The performance of the suggested method has been verified for the case of STSAT-3, Korea Science Technology Satellite.

• 천문학회보
• /
• 제46권2호
• /
• pp.37.2-37.2
• /
• 2021

Turbulence produces the density and velocity fluctuations in molecular clouds, and dense regions within the density fluctuation are the birthplace of stars. Also, turbulence can produce non-thermal pressure against gravity. Thus, turbulence plays a crucial roles in controlling star formation. However, despite many years of study, the detailed relation between turbulence and star formation remain poorly understood. As part of the Taeduk Radio Astronomy Observatory (TRAO) Key Science Program (KSP), "mapping Turbulent properties In star-forming MolEcular clouds down to the Sonic scale (TIMES; PI: Jeong-Eun Lee)", we mapped two star-forming molecular clouds, the Orion A and the ρ Ophiuchus molecular clouds, in six molecular lines (¹³CO 1-0/C¹⁸O 1-0, HCN 1-0/HCO⁺ 1-0, and CS 2-1/N₂H⁺ 1-0) using the TRAO 14-m telescope. We applied the Principal Component Analysis (PCA) to the observed data in two different ways. The first method is analyzing the variation of line intensities in velocity space to evaluate the velocity power spectrum of underlying turbulence. We investigated the relation between the star formation activities and properties of turbulence. The other method is analyzing the variation of the integrated intensities between the molecular lines to find the characteristic correlation between them. We found that the HCN, HCO⁺, and CS lines well correlate with each other in the integral shaped filament in the Orion A cloud, while the HCO⁺ line is anti-correlate with the HCN and CS lines in L1688 of the Ophiuchus cloud.

• Journal of applied mathematics & informatics
• /
• 제42권1호
• /
• pp.169-178
• /
• 2024

The purpose of this paper is to introduce the concept of pairwise fuzzy semi door spaces and study its properties and applications. The conditions for a pairwise fuzzy semi door space to become a pairwise fuzzy semi Volterra space and for a pairwise fuzzy semi Volterra space together with a pairwise fuzzy semi door space to become a pairwise fuzzy semi Baire space are established. Also, the inter-relations between pairwise fuzzy semi Volterra spaces and other fuzzy bitopological spaces such as pairwise fuzzy semi Baire space, pairwise fuzzy semi σ-Baire space, pairwise fuzzy semi D-Baire space, pairwise fuzzy semi GID-space, pairwise fuzzy semi door space are also discussed in this paper.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제20권1호
• /
• pp.47-49
• /
• 1981

In this paper, we give several properties of ordinal spaces [0, $\Omega$] and [0, $\Omega$].

• Korean Journal of Mathematics
• /
• 제12권2호
• /
• pp.117-125
• /
• 2004

We investigate some properties of functions of ${\Phi}{\Lambda}$-bound variation on a closed bounded interval, which is the generalization of bounded variation.

• 충청수학회지
• /
• 제33권4호
• /
• pp.405-412
• /
• 2020

In this paper we introduce the category of closuresequential approach spaces, CSEQ. And study some properties of closure-sequential approach space.

• 한국전산응용수학회:학술대회논문집
• /
• 한국전산응용수학회 2003년도 KSCAM 학술발표회 프로그램 및 초록집
• /
• pp.17.1-17
• /
• 2003

We study averaging properties in Banach spaces, First, we seek an averaging property equivalent to the reflexivity in Banach spaces. Second, we investigate averaging properties in Banach space using the Brunet-Sucheston's spreading model.