• Bulletin of the Korean Mathematical Society
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• v.56 no.4
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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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• v.67
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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.

• Management Science and Financial Engineering
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• v.13 no.1
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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.

• Journal of the Korean Electrochemical Society
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• v.1 no.1
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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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• v.5 no.4
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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.

• Membrane Water Treatment
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• v.2 no.4
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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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• v.28 no.2
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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).

• Journal of Korean Philosophical Society
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• v.105
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• pp.193-214
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• 2008

This paper is about to analyse Merleau-Ponty's notion of flesh on textual evidences through the structure of perception and to apply this result to his theory of the others. In the first place, we study what he thinks of philosophical investigation and thus of the essence of philosophy. With this process, we find out that perception is more important than reflection in philosophical investigation. Differently from the objective or objectivistic viewpoint, the truth of perception is revealed to go beyond distinction between consciousness and object. This truth refers to reversibility which Merleau-Ponty thinks to be the ultimate truth. The reversibility of perception leads to chiasms which reveal and unreveal the beings. In the final analysis, the flesh as reversibility is the Being in the beings. When it comes to the problem of other minds, we are confirmed through the movement of flesh that self-presence is the presence to the differentiated world, namely the others.

• Journal of Korean Port Research
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• v.13 no.1
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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.

• Tuberculosis and Respiratory Diseases
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• v.61 no.3
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• pp.227-232
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• 2006

Background: In the measurement of bronchodilator reversibility, the forced expiratory volume in one second($FEV_{1}$) and the forced vital capacity(FVC) are commonly used parameters and recommended criteria for the reversibility requiring an increase of more than 200ml and 12% above the baseline, respectively. However, aged patients do not often meet the criteria of an increase in volume(>200ml) even though the medical history of that patient is adequate for asthma. This study investigated the role of the forced expiratory volume in six seconds($FEV_{6}$) in the bronchodilator reversibility test in elderly patients. Methods: A total of 236 patients more than 65 years of age with a $FEV_{1}$/FVC ratio<80% were enrolled in this study. The bronchodilator revesibility tests were examined. With the setting $FEV_{1}$ as the baseline, the patients were divided into three groups; Group I : $$FEV_{1}{\geq_-}80%$$ of the predicted value, Group II : 60%<$FEV_{1}$<80% of the predicted value, Group III : $$FEV_{1}{\leq_-}60%$$ of the predicted value. Results: Positive reversibility in the $FEV_{1}$, $FEV_{6}$, and FVC was in 33(14.0%), 49(20.8%) and 55(23.3%). However, Group III presented with reversibility in the $FEV_{1}$, $FEV_{6}$, and FVC in 15(22.4%), 30(44.8%) and 32(47.8%) respectively. Conclusions: The $FEV_{6}$ might be used as a complementary parameter in bronchodilatror reversibility in elderly patients. However, more study will be needed to determine the usefulness of $FEV_{6}$ in bronchodilator reversibility test.