• Korean Journal of Mathematics
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• v.27 no.3
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• pp.661-690
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• 2019

The soft compactness notion via soft topological spaces was first studied in [10,29]. In this work, soft semi-open sets are utilized to initiate seven new kinds of generalized soft semi-compactness, namely soft semi-$Lindel{\ddot{o}}fness$, almost (approximately, mildly) soft semi-compactness and almost (approximately, mildly) soft semi-$Lindel{\ddot{o}}fness$. The relationships among them are shown with the help of illustrative examples and the equivalent conditions of each one of them are investigated. Also, the behavior of these spaces under soft semi-irresolute maps are investigated. Furthermore, the enough conditions for the equivalence among the four sorts of soft semi-compact spaces and for the equivalence among the four sorts of soft semi-$Lindel{\ddot{o}}f$ spaces are explored. The relationships between enriched soft topological spaces and the initiated spaces are discussed in different cases. Finally, some properties which connect some of these spaces with some soft topological notions such as soft semi-connectedness, soft semi $T_2$-spaces and soft subspaces are obtained.

• Communications of the Korean Mathematical Society
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• v.28 no.1
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• pp.79-85
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• 2013

The structure of a poset P with smallest element 0 is looked at from two view points. Firstly, with respect to the Zariski topology, it is shown that Spec(P), the set of all prime semi-ideals of P, is a compact space and Max(P), the set of all maximal semi-ideals of P, is a compact $T_1$ subspace. Various other topological properties are derived. Secondly, we study the semi-ideal-based zero-divisor graph structure of poset P, denoted by $G_I$ (P), and characterize its diameter.

• Journal of the Korean Mathematical Society
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• v.54 no.1
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• pp.117-139
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• 2017

This paper presents a systematic study for theoretical aspects of a unified approach to the abstract relative Fourier transforms over canonical homogeneous spaces of semi-direct product groups with Abelian normal factor. Let H be a locally compact group, K be a locally compact Abelian (LCA) group, and ${\theta}:H{\rightarrow}Aut(K)$ be a continuous homomorphism. Let $G_{\theta}=H{\ltimes}_{\theta}K$ be the semi-direct product of H and K with respect to ${\theta}$ and $G_{\theta}/H$ be the canonical homogeneous space (left coset space) of $G_{\theta}$. We introduce the notions of relative dual homogeneous space and also abstract relative Fourier transform over $G_{\theta}/H$. Then we study theoretical properties of this approach.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.441-449
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• 2000

Analysis, design and practical implementation of a single-stage electronic ballast for compact fluorecent lamps are presented in this paper. The proposed topology is based on a single-stage ballast which combines a boost converter and a half-bridge series resonant inverter. High power factor is achieved by using the boost semi-stage operating in discontinuous conduction mode, and inverter semi-stage operated above resonant frequency to provide zero voltage switching is employed to ballast the fluorescent lamp. Analytical and experimental results from the ballast system with 36W fluorescent lamps have demonstrated the feasibility of the proposed single-stage electronic ballast.

• Bulletin of the Korean Mathematical Society
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• v.29 no.2
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• pp.257-264
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• 1992

Since Alfsen and Effors [1] introduced the notion of an M-ideal, many authors [3,6,9,12] have worked on the problem of finding those Banach spaces X and Y for which K(X,Y), the space of all compact linear operators from X to Y, is an M-ideal in L(X,Y), the space of all bounded linear operators from X to Y. The M-ideal property of K(X,Y) in L(X,Y) gives some informations on X,Y and K(X,Y). If K(X) (=K(X,X)) is an M-ideal in L(X) (=L(X,X)), then X has the metric compact approximation property [5] and X is an M-ideal in $X^{**}$ [10]. If X is reflexive and K(X) is an M-ideal in L(X), then K(X)$^{**}$ is isometrically isomorphic to L(X)[5]. A weaker notion is a semi M-ideal. Studies on Banach spaces X and Y for which K(X,Y) is a semi M-ideal in L(X,Y) were done by Lima [9, 10].

• Communications of the Korean Mathematical Society
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• v.14 no.1
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• pp.223-231
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• 1999

In this paper we prove the existence of solutions of a nonlinear integrodifferential equation of Sobolev type with nonlocal conditions. The results are obtained by using compact semigroups and the Schauder fixed point theorem.

• Honam Mathematical Journal
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• v.26 no.4
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• pp.533-547
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• 2004

In this paper, we introduce two kinds of generalized vector quasivariational-like inequalities for multivalued mappings and show the existence of solutions to those variational inequalities under compact and non-compact assumptions, respectively.

• Journal of the Chungcheong Mathematical Society
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• v.32 no.4
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• pp.453-459
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• 2019

In this paper, we analyze the behaviour of flows near closed sets with compact boundary which contains no semi-orbits. Also, we give a condition that a closed invariant set is to be asymptotically stable.

• Kyungpook Mathematical Journal
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• v.47 no.2
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• pp.155-164
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• 2007

It is the objective of this paper to study further the notion of ${\Lambda}_s$-semi-${\theta}$-closed sets which is defined as the intersection of a ${\theta}$-${\Lambda}_s$-set and a semi-${\theta}$-closed set. Moreover, introduce some low separation axioms using the above notions. Also we present and study the notions of ${\Lambda}_s$-continuous functions, ${\Lambda}_s$-compact spaces and ${\Lambda}_s$-connected spaces.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.473-478
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• 2005

Active suspension system improves ride quality with optimized suspension force, generated by electric, hydrolic or pneumatic power and controlled by micro-processor under various operation condition of train, while Semi-Active susepsion system provides optimized and controlled characteristics of suspensions such as damping coefficient without external energy. The benefits fo Semi-Active suspension are no required power source and to be made compact with lower cost. Train with narrow gauge could be more unstable than one for normal or wide gauge, and it could be more vibrated than others one by external force such as aerodynamic force and track irregularity. So, the reduced ride quality could be improved with appling with Semi-active suspension system. In this report, the Semi-Active suspension system for narrow gauge train shall be proposed and to prepare the Roller Rig test of this train, integration of system, development of control algorithm and confirmation of its performance with simulation tool would be taken.