• Kyungpook Mathematical Journal
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• v.61 no.4
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• pp.791-803
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• 2021

Earlier investigators have made detailed studies of geometric properties such as integrability, partial integrability, and invariants, such as the fundamental 2-form, of some canonical f-structures, such as f³ ± f = 0, on the frame bundle FM. Our aim is to study metallic structures on the frame bundle: polynomial structures of degree 2 satisfying F² = pF +qI where p, q are positive integers. We introduce a tensor field F_α, α = 1, 2…, n on FM show that it is a metallic structure. Theorems on Nijenhuis tensor and integrability of metallic structure F_α on FM are also proved. Furthermore, the diagonal lifts g^D and the fundamental 2-form Ω_α of a metallic structure F_α on FM are established. Moreover, the integrability condition for horizontal lift F_α^H of a metallic structure F_α on FM is determined as an application. Finally, the golden structure that is a particular case of a metallic structure on FM is discussed as an example.

• Communications of the Korean Mathematical Society
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• v.14 no.1
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• pp.201-210
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• 1999

We introduce the notion of the Finsler metrics compatible with f(5,1)-structure and investigate the properties of Finsler space with such metrics.

• Communications of the Korean Mathematical Society
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• v.15 no.2
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• pp.339-348
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• 2000

We introduce the notion of the Finsler metrics compat-ible with a special Riemannian structure f of type (1,1) satisfying f6+f2=0 and investigate the properties of Finsler space with them.

• Kyungpook Mathematical Journal
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• v.50 no.4
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• pp.455-463
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• 2010

The differentiable manifold with f - structure were studied by many authors, for example: K. Yano [7], Ishihara [8], Das [4] among others but thus far we do not know the geometry of manifolds which are endowed with special polynomial $F_{a(j){\times}(j)$-structure satisfying $$\prod\limits_{j=1}^{k}\;[F^2+a(j)F+\lambda^2(j)I]\;=\;0$$ However, special quadratic structure manifold have been defined and studied by Sinha and Sharma [8]. The purpose of this paper is to study the geometry of differentiable manifolds equipped with such structures and define special polynomial structures for all values of j = 1, 2,$\ldots$,$K\;\in\;N$, and obtain integrability conditions of the distributions $\pi_m^j$ and ${\pi\limits^{\sim}}_m^j$.

• Journal of IKEEE
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• v.27 no.4
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• pp.399-404
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• 2023

In this paper, we analyzed the current path in the O/N/O (Oxide/Nitride/Oxide) structure of 3D NAND Flash memory and in the O/N/F (Oxide/Nitride/Ferroelectric) structure where the blocking oxide is replaced by a ferroelectric. In the O/N/O structure, when V_read is applied, a current path is formed on the backside of the channel due to the E-fields of neighboring cells. In contrast, the O/N/F structure exhibits a current path formed on the front side due to the polarization of the ferroelectric material, causing electrons to move toward the channel front. Additionally, we performed an examination of device characteristics considering channel thickness and channel length. The analysis results showed that the front electron current density in the O/N/F structure increased by 2.8 times compared to the O/N/O structure, and the front electron current density ratio of the O/N/F structure was 17.7% higher. Therefore, the front current path is formed more effectively in the O/N/F structure than in the O/N/O structure.

• Journal of the Korean Home Economics Association
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• v.31 no.4
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• pp.115-132
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• 1993

This study was designed with the purpose to analyze the factor structure of family life events and to clear the influence of related variables on family life events. The frequence of experienced events and the degree of importance of events which were the constituent components of family life events was estimated by the 650 married woman in Kangju. The results were as follows: 1. 15 factors of family life events derived by factor analysis: F.1「Expenditure and economic loss」, F.2「Growth and change of children」, F.3「Change of family structure」, F.4「Family's change」, F.5「Change of life level」, F.6「Family's social problem」, F.7「Need of care」, F.8「Family's health」, F.9「Marital relationship」, F.10「Family's social damage」, F.11「Breach with acquaintance」, F.12「Financial difficulties」F.13「Husband's problem」, F.14「Housewives' social activity」, F.15「Kinship's support」. 2. There frequence of experienced family life events such as expenditure and economic loss and breach with acquaintance was highest. 3. The degree of importance about experienced family life events such as growth and change of children was highest. 4. Age, family life cycle have significantly differenced on the degree of importance and the frequence of experienced events. 5. Education's level, family size, income, housewives' employment and family structure have differently differenced on the degree of importance and the frequence of experienced events according event factor.

• Bulletin of the Korean Mathematical Society
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• v.36 no.2
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• pp.217-224
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• 1999

In this paper the properties of the Finsler metrics compatible with an f-structure are investigated.

• Kyungpook Mathematical Journal
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• v.18 no.2
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• pp.277-283
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• 1978

The first part of this paper is devoted to the study of F-structure satisfying: $F^K+(-)^{K+1}F=0$ and $F^W+(-)^{W+1}F{\neq}0$, for 1$${\geq_-}3$$) has been considered. In the later part some structures involving Lie-derivatives. exterior and co-derivatives have been studied.

• Journal of the Korean Society of Safety
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• v.11 no.4
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• pp.16-23
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• 1996

In controlling manipulators interacting with the external environment, an important role is played by the Force/Torque(F/T) sensors. Recently, a number of structures for F/T sensors have been proposed, and some criteria for their evaluation have been introduced. This paper presents a systematic analysis of F/T sensor at the design stage. A model of the F/T sensors, based on Stewart Platform structure, is developed on the basis of static and kinematic equation. The condition number defined by the kinematic velocity and force analysis of F/T sensor is used as a performance Index. Thus, 4 optimal structure factors of 6 D.O. F. F/T sensor are determined by using the condition number.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.696-700
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• 2010

We fabricated red and blue organic light emitting display (OLEDs) which had the two kinds of multi-structure of ITO/HIL/HTL/EML/ETL/LiF/Al and ITO/HIL/HTL/EML/ETL/LiF/Al/LiF. In the case of red OLED that had LiF/Al/LiF structure compared to LiF/Al structure, the current density increased from 4.3 mA/$cm^2$ to 7.3 mA/$cm^2$, and the brightness increased from 488 cd/$m^2$ to 1,023 cd/$m^2$ at 7.0 V, and as a result the current efficiency was improved from 11.28 cd/A to 13.95 cd/A. Also in the case of blue OLED that had LiF on Al cathode layer, the current density increased from 1.2 mA/$cm^2$ to 1.8 mA/$cm^2$, and the brightness increased from 45 cd/$m^2$ to 85 cd/$m^2$ at 7.0 V, and as a result the current efficiency was improved from 3.69 cd/A to 4.82 cd/A. Through these experimental results it could be suggested that the LiF layer formed on Al prevents the oxidation of Al surface, and the electrode resistance become low with increase of supplied electrons, therefore the brightness and the efficiency are improved from the influence to the well-balanced bonding of electron and hole at emitting layer.