• 대한수학회논문집
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• 제36권2호
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• pp.209-227
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• 2021

In this paper, we deal with the question that what kind of properties does a ring gain when it satisfies symmetricity or reversibility by the way of nilpotent elements? By the motivation of this question, we approach to symmetric and reversible property of rings via nilpotents. For symmetricity, we call a ring R middle right-(resp. left-)nil symmetric (mr-nil (resp. ml-nil) symmetric, for short) if abc = 0 implies acb = 0 (resp. bac = 0) for a, c ∈ R and b ∈ nil(R) where nil(R) is the set of all nilpotent elements of R. It is proved that mr-nil symmetric rings are abelian and so directly finite. We show that the class of mr-nil symmetric rings strictly lies between the classes of symmetric rings and weak right nil-symmetric rings. For reversibility, we introduce left (resp. right) N-reversible ideal I of a ring R if for any a ∈ nil(R), b ∈ R, being ab ∈ I implies ba ∈ I (resp. b ∈ nil(R), a ∈ R, being ab ∈ I implies ba ∈ I). A ring R is called left (resp. right) N-reversible if the zero ideal is left (resp. right) N-reversible. Left N-reversibility is a generalization of mr-nil symmetricity. We exactly determine the place of the class of left N-reversible rings which is placed between the classes of reversible rings and CNZ rings. We also obtain that every left N-reversible ring is nil-Armendariz. It is observed that the polynomial ring over a left N-reversible Armendariz ring is also left N-reversible.

• 충청수학회지
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• 제28권4호
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• pp.561-573
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• 2015

The aim of this paper is to introduce the notion of left-right (resp. right-left) symmetric bi-derivation of BCH-algebras and some related properties are investigated.

• 대한수학회보
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• 제44권4호
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• pp.777-788
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• 2007

An endomorphism ${\alpha}$ of a ring R is called right(left) symmetric if whenever abc=0 for a, b, c ${\in}$ R, $ac{\alpha}(b)=0({\alpha}(b)ac=0)$. A ring R is called right(left) ${\alpha}-symmetric$ if there exists a right(left) symmetric endomorphism ${\alpha}$ of R. The notion of an ${\alpha}-symmetric$ ring is a generalization of ${\alpha}-rigid$ rings as well as an extension of symmetric rings. We study characterizations of ${\alpha}-symmetric$ rings and their related properties including extensions. The relationship between ${\alpha}-symmetric$ rings and(extended) Armendariz rings is also investigated, consequently several known results relating to ${\alpha}-rigid$ and symmetric rings can be obtained as corollaries of our results.

• 대한수학회지
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• 제52권3호
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• pp.489-501
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• 2015

We study the structure of right duo ring property when it is restricted within the group of units, and introduce the concept of right unit-duo. This newly introduced property is first observed to be not left-right symmetric, and we examine several conditions to ensure the symmetry. Right unit-duo rings are next proved to be Abelian, by help of which the class of noncommutative right unit-duo rings of minimal order is completely determined up to isomorphism. We also investigate some properties of right unit-duo rings which are concerned with annihilating conditions.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제17권2호
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• pp.131-136
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• 2010

Throught this paper, we will investigate some properties of left regular and strongly reduced near-rings. Mason introduced the notion of left regularity and he characterized left regular zero-symmetric unital near-rings. Also, this concept have been studied by several authors. The purpose of this paper is to find some characterizations of the strong reducibility in near-rings, and the strong regularity in near-rings which are closely related with strongly reduced near-rings.

• 한국항행학회논문지
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• 제17권2호
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• pp.196-201
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• 2013

본 논문은 대칭 구조의 CRLH 전송선로를 바탕으로 이중모드에서 동작하는 평형 필터 설계를 제안한 것이다. 기존의 대칭 구조와는 다르게 이 구조에서는 공통 모드와 차동 모드의 이중모드에서 동작한다. 이러한 성질은 이 구조의 대칭면에 단락회로를 그라운드 비아에 의해서 동작되도록 구현하였다. 이렇게 하면 공통 모드와 차동 모드에서 모두 동작하는 특성을 얻을 수 있으며, 이러한 성질을 이용하여 평형 필터를 구현하였다. 이러한 특징들을 확인하기 위하여 5개의 대칭 CRLH 단위 셀로 시뮬레이션, 제작 및 측정을 하여 공통 모드와 차동 모드에서 동일하게 동작하는 평형 필터의 특성을 얻었다.

• 한국가시화정보학회지
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• 제11권1호
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• pp.48-52
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• 2013

This paper presents experimental observation of asymmetric electrohydrodynamic flow generated around a pair of symmetric coplanar electrodes. Electrodes are attached on the bottom of the cavity containing a dielectric liquid, i.e., a mixture of dodecane and 0.5% wt Span80. In the first experiment, an AC voltage of 1500 V is applied with the frequency varying in the range 10~500 hz and the left electrode being grounded. The flow patterns show that the center line of vortices is unexpectedly tilted to the left side. If the right side electrode is grounded, the center line is tilted to the right side. The magnitude of the fluid velocity shows an irregular variation with the frequency in the range 10 Hz~100 Hz, beyond which it simply decays. In the second experiment, we applied fixed AC with 1000 V and 60 Hz superposed by DC voltage varying in the range -1000 V ~ +1000 V. The center line of the flow pattern is tilted to the right side with positive DC voltage and to the left side with negative DC. We have managed to show that the flow pattern can be symmetric with a suitable combination of DC and AC, e.g., DC 850 V plus AC 1000 V with the frequency 10 Hz.

• 대한수학회보
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• 제55권1호
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• pp.25-40
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• 2018

We focus on the structure of the set of noncentral idempotents whose role is similar to one of central idempotents. We introduce the concept of quasi-Abelian rings which unit-regular rings satisfy. We first observe that the class of quasi-Abelian rings is seated between Abelian and direct finiteness. It is proved that a regular ring is directly finite if and only if it is quasi-Abelian. It is also shown that quasi-Abelian property is not left-right symmetric, but left-right symmetric when a given ring has an involution. Quasi-Abelian property is shown to do not pass to polynomial rings, comparing with Abelian property passing to polynomial rings.

• 대한물리치료과학회지
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• 제15권4호
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• pp.11-17
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• 2008

Background: Human body is formed of symmetric bilateral structures that are comprised of eye, upper arm, lower arm and etc. but, we are used only dominant components. The purpose of this study was to analysis length cognition ability in dominant eye. Methods: Total 88 persons (male 18, female 70) were participated in this study. They were tested with ‘hole in the card’ test for identification of dominant eye's side, then the length cognition ability was measured in right & left axillary level by describing 10cm line. Results: The results by independent t-test were as follows. In difference of length cognition ability in right axillary level between right dominant eyed group & left dominant eyed group, right dominant eyed group was superior to left dominant eyed group, but significant difference was not existed statistically(p>.05). In left axillary level, right dominant eyed group was superior to left dominant eyed group, but significant difference was not existed statistically(p>.05). Conclusion: These result can be applied to the learning of palpation & observation skill in physical therapy, although this study was not identify a relation between dominant eye & dominant hand.

• 대한물리치료과학회지
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• 제16권4호
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• pp.59-65
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• 2009

Background: Human body is formed of symmetric bilateral structures that are comprised of eye, upper arm, lower arm and etc. but, we are used only dominant components. The purpose of this study was to analysis length cognition ability in dominant eye & hand. Method: Total 180 persons (male 32, female 138) were participated in this study. They were tested with 'hole in the card' test for identification of dominant eye's side and the question for identification of dominant hand's side, then the length cognition ability was measured in right & left axillary level by describing 10cm line. Results: The results by independent t-test were as follows. In difference of length cognition ability in right axillary level between right dominant eyed group & left dominant eyed group, right dominant eyed group was superior to left dominant eyed group, but significant difference was not existed statistically(p>.05). In left axillary level, right dominant eyed group was superior to left dominant eyed group, but significant difference was not existed statistically(p>.05). In axillary level of dominant eye's side, non-crossed group was superior to crossed group, but significant difference was not existed statistically(p>.05). In axillary level of non-dominant eye's side, non-crossed group was superior to crossed group, but significant difference was not existed statistically(p>.05). Conclusion: These result can be applied to the learning of palpation & observation skill in physical therapy.