• 대한수학회지
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• 제59권4호
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• pp.651-684
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• 2022

Let G be an arbitrary, connected, simply connected and unimodular Lie group of dimension 3. On the space 𝔐(G) of left-invariant Lorentzian metrics on G, there exists a natural action of the group Aut(G) of automorphisms of G, so it yields an equivalence relation ≃ on 𝔐(G), in the following way: h₁ ≃ h₂ ⇔ h₂ = 𝜙^*(h₁) for some 𝜙 ∈ Aut(G). In this paper a procedure to compute the orbit space Aut(G)/𝔐(G) (so called moduli space of 𝔐(G)) is given.

• Journal of Electrochemical Science and Technology
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• 제9권4호
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• pp.320-329
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• 2018

Natural graphite is obtained from an abandoned open-cast mine and purified by a simple, eco-friendly and affordable beneficiation process including ball milling and flotation process. Both raw graphite (55 wt %) and its concentrate (85 wt %) were electrochemically tested in order to evaluate these materials as anode materials for Li-ion and Na-ion batteries. It was found that both raw and purified graphites exhibit good electrochemical activities with respect to lithium and sodium ions through completely different reaction mechanisms. The encouraging results demonstrated in this work suggest that both raw and graphite concentrates after flotation could be used respectively for stationary and embedded applications. This strategy would help in developing local electrical storage systems with a significantly low environmental footprint.

• 대한수학회논문집
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• 제33권3호
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• pp.853-869
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• 2018

We give a new characterization of Browder's theorem through equality between the pseudo B-Weyl spectrum and the generalized Drazin spectrum. Also, we will give conditions under which pseudo B-Fredholm and pseudo B-Weyl spectrum introduced in [9] and [25] become stable under commuting Riesz perturbations.

• 대한수학회보
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• 제56권3호
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• pp.631-648
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• 2019

In this paper, we consider a semilinear stochastic heat equation driven by an additive fractional white noise. Under the pathwise uniqueness property, we establish various strong stability results. As a consequence, we give an application to the convergence of the Picard successive approximation.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제28권2호
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• pp.119-142
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• 2021

In this paper, we first introduce a new L_p analytic Fourier-Feynman transform with respect to subordinate Brownian motion (AFFTSB), which extends the Fourier-Feynman transform in the Wiener space. We next examine several relationships involving the L_p-AFFTSB, the convolution product, and the gradient operator for several types of functionals.

• 식품보건융합연구
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• 제6권3호
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• pp.23-29
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• 2020

Blood transfusion in the neonatal period remains a therapeutic act, that no one dares to consider it as perfectly innocuous and that it is advisable to make rare, considering its risks as well immunological as infectious. The present work is a retrospective study, conducted in neonatal intensive care unit, in the University Hospital MOHAMED VI, Marrakech, during the period from January 1^st to December 31^st, 2019. All newborns were included in this work, who received one or multiple transfusions of red blood cells (RBC). Our study covered 60 neonates with a total of birth: 794 neonates, with a prevalence of 7.55%, hospitalized for various indications (60% of newborns were at term, 31.7% premature and 8, 33% were post-mature. The majority of transfusion procedures were performed during the first week of life. This is explained by the frequency of haemolytic anemias by fœto-maternal incompatibility. The main indications for transfusion were haemolysis, anemic syndrome and haemorrhagic syndrome. The average number of transfusion episodes was 1.95 +/- 1.47 per patient. Newborns were polytransfused in 18.33% of cases. A single transfusion accident was found in our study. However, we did not observe a correlation between the maternal diseases, the state of the newborn, and the transfusional indication.

• 대한수학회보
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• 제54권2호
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• pp.485-495
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• 2017

The aim of this paper is twofold. Firstly, we introduce the concept of semi-partial isometry in a Banach algebra and carry out a comparison and a classification study for this concept. In particular, we show that in the context of $C^*$-algebras this concept coincides with the notion of partial isometry. Our results encompass several earlier ones concerning partial isometries in Hilbert spaces, Banach spaces and $C^*$-algebras. Finally, we study the notion of (m, p)-semi partial isometries.

• 충청수학회지
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• 제21권4호
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• pp.501-510
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• 2008

The distribution of the sum of n independent random variables having exponential distributions with different parameters ${\beta}_i$ ($i=1,2,{\ldots},n$) is given in [2], [3], [4] and [6]. In [1], by using Laplace transform, Jasiulewicz and Kordecki generalized the results obtained by Sen and Balakrishnan in [6] and established a formula for the distribution of this sum without conditions on the parameters ${\beta}_i$. The aim of this note is to present a method to find the distribution of the sum of n independent exponentially distributed random variables with different parameters. Our method can also be used to handle the case when all ${\beta}_i$ are the same.

• Journal of Information Processing Systems
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• 제11권4호
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• pp.495-508
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• 2015

In this paper, a novel robust medical images watermarking scheme is proposed. In traditional methods, the added watermark may alter the host medical image in an irreversible manner and may mask subtle details. Consequently, we propose a method for medical image copyright protection that may remedy this problem by embedding the watermark without modifying the original host image. The proposed method is based on the visual cryptography concept and the dominant blocks of wavelet coefficients. The logic in using the blocks dominants map is that local features, such as contours or edges, are unique to each image. The experimental results show that the proposed method can withstand several image processing attacks such as cropping, filtering, compression, etc.

• 대한수학회지
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• 제56권1호
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• pp.149-167
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• 2019

In this work, we study the existence, uniqueness and stability in the ${\alpha}$-norm of solutions for some stochastic partial functional integrodifferential equations. We suppose that the linear part has an analytic resolvent operator in the sense given in Grimmer [8] and the nonlinear part satisfies a $H{\ddot{o}}lder$ type condition with respect to the ${\alpha}$-norm associated to the linear part. Firstly, we study the existence of the mild solutions. Secondly, we study the exponential stability in pth moment (p > 2). Our results are illustrated by an example. This work extends many previous results on stochastic partial functional differential equations.