• Kyungpook Mathematical Journal
• /
• v.61 no.2
• /
• pp.239-248
• /
• 2021

In this paper we study modules with the W F I⁺-extending property. We prove that if M satisfies the W F I⁺-extending, pseudo duo properties and M/(Soc M) has finite uniform dimension then M decompose into a direct sum of a semisimple submodule and a submodule of finite uniform dimension. In particular, if M satisfies the W F I⁺-extending, pseudo duo properties and ascending chain (respectively, descending chain) condition on essential submodules then M = M₁ ⊕ M₂ for some semisimple submodule M₁ and Noetherian (respectively, Artinian) submodule M₂. Moreover, we show that if M is a W F I-extending module with pseudo duo, C₂ and essential socle then the quotient ring of its endomorphism ring with Jacobson radical is a (von Neumann) regular ring. We provide several examples which illustrate our results.

• Communications of the Korean Mathematical Society
• /
• v.10 no.3
• /
• pp.545-560
• /
• 1995

In this paper, we show one family of normal quintic surfaces in $P^3$ which are birationally isomorphic to Enriques surfaces. We prove that the dimension of the moduli space of these Enriques surfaces is 6.

• Communications of the Korean Mathematical Society
• /
• v.13 no.1
• /
• pp.95-107
• /
• 1998

In this paper we prove the Hopf-Rinow theorem for CAT(0) spaces and show that the ideal boundaries of complete CAT(0) manifolds of dimension 2 or 3 with some additional conditions are homeomorphic to the circle or 2-sphere by the characterization of the local shadows around the branch points.

• Journal of the Korean Society of Costume
• /
• v.50 no.7
• /
• pp.181-193
• /
• 2000

The purpose of this study was to establish the marketing strategy, that strengthens the brand royalty of their own in apparel industry and that can induce consumer's brand switching against competitive brand. This might be done by suggesting influencing factors on the brand switching for fashion goods. This study was classified into theoretical and experimental study Experimental study was done, using the survey to prove the models for consumers' responses to brand switching by the theoretical study. The survey was conducted through two preliminary questionnaires. It was used as a criterion to prove the validity of the main survey and analyse the reliability. It analyzed at last five hundred ninety-two women in the age of twenty to thirty years odd who live in Seoul and the suburban of Seoul. Followings are the summary of the results revealed through the experimental study. First, brand switching behavior of consumers far formal dress was attributed to two extremes the inner motivation of variety seeking tendency and communication contact, complex variety seeking group, true variety seeking group, derived variety seeking group, and variety avoiding group. Second, the structure of low dimension related fashion according to factor analysis, which affects brand switching, was composed to involvement in 5-dimension, information search in 3-dimension. Based on the results of this study the types of brand switching in fashion goods can be classified by the variety seeking tendency. as inner motivation, and level of contact communication as a outside stimuli. In addition this study showed a correlation among the factors for brand switching related to variables of fashion.

• Bulletin of the Korean Mathematical Society
• /
• v.57 no.2
• /
• pp.275-280
• /
• 2020

Let (R, m) be a Noetherian local Cohen-Macaulay ring and I be a proper ideal of R. Assume that β_R(I, R) denotes the constant value of depth_R(R/Iⁿ) for n ≫ 0. In this paper we introduce the new notion γ_R(I, R) and then we prove the following inequalities: β_R(I, R) ≤ γ_R(I, R) ≤ dim R - cd(I, R) ≤ dim R/I. Also, some applications of these inequalities will be included.

• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.503-509
• /
• 2004

With modem computational fluid dynamics method (CFD), air-charging models of the air brake pipe system and auxiliary reservoir are built. Compared with one-dimension model, no empirical formula is introduced to solve branch pipe fields for two-dimension model. A modified operator-splitting method is presented to solve the coupled equations of pressure and velocity, and numerical simulation shows that it is very stable. Compare the numerical results with empirical data of heavy haul trains in home and abroad so as to prove the correctness of the theory and algorithm presented. This paper gives theoretic reference to the experiments of braking effects of heavy haul trains, and forms a basis for development of complete freight train air brake system simulation.

• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.9
• /
• pp.13-23
• /
• 1996

When artificial potential field approach is used to avoid obstacle, the problem can be occurred in case that manipulator selects the path which across over an obstacle among paths. In thiscase manipulator can't reach the desired goal form obstacle. This problem is a case of structual local minimum. so this paper proposes the method to solve structual local minimum in this case. The method is that the manipulator goes via temporary goal. This paper proposes that visual region concept to select the temporary goal. The temporary goal is selected on the border of the visual region. To prove its effectiveness, two simulation examples are done by two link manipulator in two dimension and by three link manipulator in three dimension.

• Journal of the Korean Mathematical Society
• /
• v.56 no.5
• /
• pp.1285-1307
• /
• 2019

For a multiplication R-module M we consider the Zariski topology in the set Spec (M) of prime submodules of M. We investigate the relationship between the algebraic properties of the submodules of M and the topological properties of some subspaces of Spec (M). We also consider some topological aspects of certain frames. We prove that if R is a commutative ring and M is a multiplication R-module, then the lattice Semp (M/N) of semiprime submodules of M/N is a spatial frame for every submodule N of M. When M is a quasi projective module, we obtain that the interval ${\uparrow}(N)^{Semp}(M)=\{P{\in}Semp(M){\mid}N{\subseteq}P\}$ and the lattice Semp (M/N) are isomorphic as frames. Finally, we obtain results about quantales and the classical Krull dimension of M.

• Journal of the Korean Mathematical Society
• /
• v.59 no.4
• /
• pp.821-841
• /
• 2022

In this paper, we introduce and study regular rings relative to the hereditary torsion theory w (a special case of a well-centered torsion theory over a commutative ring), called w-regular rings. We focus mainly on the w-regularity for w-coherent rings and w-Noetherian rings. In particular, it is shown that the w-coherent w-regular domains are exactly the Prüfer v-multiplication domains and that an integral domain is w-Noetherian and w-regular if and only if it is a Krull domain. We also prove the w-analogue of the global version of the Serre-Auslander-Buchsbaum Theorem. Among other things, we show that every w-Noetherian w-regular ring is the direct sum of a finite number of Krull domains. Finally, we obtain that the global weak w-projective dimension of a w-Noetherian ring is 0, 1, or ∞.

• Bulletin of the Korean Mathematical Society
• /
• v.48 no.6
• /
• pp.1125-1128
• /
• 2011

Let R be a commutative Noetherian ring, a an ideal of R, and M a minimax R-module. We prove that the local cohomology modules $H^j_a(M)$ are a-cominimax; that is, $Ext^i_R$(R/a, $H^j_a(M)$) is minimax for all i and j in the following cases: (a) dim R/a = 1; (b) cd(a) = 1, where cd is the cohomological dimension of a in R; (c) dim $R{\leq}2$. In these cases we also prove that the Bass numbers and the Betti numbers of $H^j_a(M)$ are finite.