• 대한수학회보
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• 제56권4호
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• pp.993-1006
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• 2019

This article concerns a ring property which preserves the reversibility of elements at nonzero idempotents. A ring R shall be said to be quasi-reversible if $0{\neq}ab{\in}I(R)$ for a, $b{\in}R$ implies $ba{\in}I(R)$, where I(R) is the set of all idempotents in R. We investigate the quasi-reversibility of 2 by 2 full and upper triangular matrix rings over various kinds of reversible rings, concluding that the quasi-reversibility is a proper generalization of the reversibility. It is shown that the quasi-reversibility does not pass to polynomial rings. The structure of Abelian rings is also observed in relation with reversibility and quasi-reversibility.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.312-315
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• 2018

Although the reversibility of 10,12-pentacosadiynoic amino meta-acid(PCDA-mBzA) against temperature and pH was reported, the modulation of reversibility by ion adsorption at terminal functional group has not been investigated. In this work, we developed a simple method for modulating the reversibility of PCDA-mBzA films upon a thermal stimulus by cadmium ion adsorption inducing the breakage of the outer hydrogen bonding of two hydrogen bonds, which are responsible for the reversible properties of PCDA-mBzA. External reflection-Fourier transform infrared (ER-FTIR) analyses revealed that the hydrogen bonding between the carboxylic acid groups was broken through ion adsorption and only a single hydrogen bond between the amide groups remained in the PCDA-mBzA polymer. In addition, PCDA-mBzA films could recover their original property through cadmium ion desorption. These results present that the transition between reversibility and irreversibility can be modulated artificially simply through the adsorption and desorption of metal ions.

• 전기화학회지
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• 제1권1호
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• pp.8-13
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• 1998

This work presents the way how to evaluate the degree of reversibility of the discharging process undergone by the nickel hydroxide film cathodically deposited on pure nickel as a positive electrode for electrochemical capacitor using the combined cyclic voltammetry and potential drop method, supplemented by galvanostatic discharge and open-circuit potential transient methods. The time interval necessary just to establish the current reversal of anodic to cathodic direction from the moment just after applying the potential inversion of anodic to cathodic direction, was obtained on cyclic voltammogram. The cathodic charge density passed upon dropping the applied potential, was calculated on potentiostatic current density-time curve. Both the time interval and the cathodic charge density in magnitude can be regarded as being measures of the degree of reversibility of the discharging process undergone by the positive active material for supercapacitor, i.e. , the longer the time interval is, the lower is the degree of reversibility and the greater the cathodic charge density is, the higher is the degree of reversibility. From the applied potential dependences of the time interval and cathodic charge density, discharge at $0.42 V_{SCE}$ was determined to be the most reversible.

• International Journal of Control, Automation, and Systems
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• 제5권4호
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• pp.463-470
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• 2007

Colored Petri net model which is a model of discrete event systems is considered in this work. A supervisory controller which enforces reversibility and liveness simultaneously is presented. Furthermore, the algorithms, written by pseudo-code, are presented for the supervisory controller design. A program is developed to implement these algorithms.

• Management Science and Financial Engineering
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• 제13권1호
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• pp.25-34
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• 2007

This paper is concerned with proving a conjecture that the two stage assembly system is reversible in deterministic makespan scheduling context. The reversibility means that a job sequence in the assembly system has the same makespan as that of its reverse sequence in the disassembly system which is the reversal of the assembly system. The proposed conjecture shows that the reversibility of serial flowshops can be extended to non-serial and synchronized shops.

• Membrane and Water Treatment
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• 제2권4호
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• pp.225-237
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• 2011

In this study, response of reversibility of membrane flux during chemically enhanced backwash (CEB) to changes in filtration time, filtration flux and coagulant concentration dosing during ultrafiltration (UF) process was investigated using a regression model. The model was developed via empirical modelling approach using response surface methodology. In developing the model, statistically designed UF experiments were conducted and the results compared with the model output. The results showed that the performance of CEB, evaluated in terms of the reversibility of the membrane flux, depends strongly on the changes in coagulant concentration dosage and the filtration flux. Also the response of the reversibility of membrane flux during CEB is independent of the filtration time. The variance ratio, VR << $F_{value}$ and $R^2$ = 0.98 obtained from the cross-validation experiments indicate perfect agreement of the model output with experimental results and also testify to the validity and suitability of the model to predict reversibility of the membrane flux during CEB in UF operation.

• Kyungpook Mathematical Journal
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• 제28권2호
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• pp.123-128
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• 1988

In the present paper, using the method of Quasi-Reversibility of R. Lattes and J.L. Lions[7], we have applied this method for a system governed by parabolic operator with an infinite number of variables. (The control here is an initial condition).

• 벤처혁신연구
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• 제3권1호
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• pp.165-182
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• 2020

본 연구는 간접세인 부가가치세가 지니고 있는 조세부담의 역진성 완화방안과 급격하게 증가하는 사회복지 재원 등 공공재원의 확보 문제를 검토하고, 각 대안에 대한 실질적인 도입 방안을 제시하고자 한다. 부가가치세는 간접세이며, 일반소비세로서 모든 재화와 용역의 공급에 대하여 최종소비자가 조세부담을 함으로서 소득을 세원으로 하는 조세와 비교할 때 경제적 효율성을 지니고 있다. 그러나 조세부담의 역진성으로 인해 공평과세에 있어서는 부적합한 조세라고 보고 있다. 우리나라의 경우 부가가치세율 인상의 경제적 효과는 매우 크기 때문에 부가가치세율의 인상은 쉽지 않다. 그러나 장기적으로는 경제, 사회, 환경 및 에너지, 노령화 등의 문제와 관련하여 부가가치세율의 인상 가능성이 높다고 판단된다. 그러므로 향후 부가가치세율 인상의 논의가 이루어지는 경우 반드시 조세부담의 역진성 문제에 대해 다각도의 정책대안들이 모색되어야만 한다. 이에 본 연구에서는 현행 부가가치세가 가지고 있는 조세부담의 역진성을 파악하고 이를 기초로 정책적 대안들을 제시하고자 하였다. 첫째, 역진성을 완화하기 위해 도입된 면세제도의 적절한 조정과 면세품목 확대와 함께 개별소비세 품목의 조정도 이루어져야 한다. 따라서 둘째, 소득수준 향상과 사회적 배려를 고려하여 면세품목에 대한 조정이 이루어져야할 것이다. 셋째, 실질적인 고소득층의 고가 재화 및 용역의 소비에 대해 세율을 인상 조정함으로써 역진성의 완화를 도모해야 한다. 마지막으로 부가가치세의 특징 중 조세전가의 원리를 심각하게 훼손하고 있는 간이과세제도의 정비가 이루어져야할 것이다.

• 철학연구
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• 제105권
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• pp.193-214
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• 2008

이 논문은 메를로-퐁티의 지각 이론에서 출발하여 살의 개념을 체계적으로 분석하고 살의 관점에서 타자 문제를 어떻게 다루는가를 연구한다. 먼저, 메를로-퐁티가 철학적 주제로 삼고 있는 것이 무엇인가를 살펴본다. 철학적 물음은 세계와 이성의 신비를 푸는 문제로서, 이 문제가 반성적 분석의 대상일 수 없음을 밝힌다. 반성보다 선행하는 것이 지각이며 이 지각이 보통 사람들이 말하고 이해하는 지각이 아님을 보여준다. 메를로-퐁티의 현상학적 철학은 지각된 세계의 본연의 모습을 기술하는 것이 그 본질 목적이나, 사람들은 객관적 태도와 객관주의적 사고방식에 젖어 지각된 세계를 표상적으로만 이해하고 있다. 지각의 본성을 있는 그대로 기술함으로써 그 구조가 가역성에 있음을 규명한다. 지각의 가역성을 거쳐 살의 가역성에 이르고 살로써 타자 문제를 해결할 수 있는 한 가지 대안적 입장을 제시한다.

• 한국항만학회지
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• 제13권1호
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• pp.79-86
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• 1999

This paper deals with the evaluation problem of complex systems by introducing a fuzzy approach. The authors are functionally supposing a hierarchical structure model of a complex system and give light on the following problems. First for the purpose of clarifying the characteristics of measures the property and differences between two method such as linear and fuzzy viewpoint are discussed through two level-down evaluation process. Second the integrated evaluation process which keeps reversibility between hierarchical levels is discussed and obtained some necessary conditions for reversibility of fuzzy evaluation. From these results it is expected that the fuzzy approach overcomes partly the limitation of reductionism at the hierarchical evaluation of complex systems.