• Korean Journal of Mathematics
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• 제31권2호
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• pp.139-144
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• 2023

In this paper, we show that a recurrent manifold with harmonic curvature tensor is locally symmetric and that an Einstein and conformally recurrent manifold is locally symmetric. As a consequence, Einstein and recurrent manifolds must be locally symmetric. On the other hand, we have obtained some results for a (conformally) recurrent manifold with parallel vector field and also investigated some results for a (conformally) recurrent manifold with concircular vector field.

• 대한수학회보
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• 제59권6호
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• pp.1595-1603
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• 2022

We show how some of well-known recurrent operators such as recurrent curvature operator, recurrent Ricci operator, recurrent Jacobi operator, recurrent shape and Weyl operators have the significant role for biharmonic hypersurfaces to be minimal in the Euclidean space.

• Kyungpook Mathematical Journal
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• 제51권1호
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• pp.109-124
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• 2011

The main objective of the paper is to provide a full classification of quasi-conformally recurrent Riemannian manifolds with harmonic quasi-conformal curvature tensor. Among others it is shown that a quasi-conformally recurrent manifold with harmonic quasi-conformal curvature tensor is any one of the following: (i) quasi-conformally symmetric, (ii) conformally flat, (iii) manifold of constant curvature, (iv) vanishing scalar curvature, (v) Ricci recurrent.

• 대한후두음성언어의학회지
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• 제11권2호
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• pp.188-191
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• 2000

In thyroid and parathyroid surgery, damage to the recurrent laryngeal nerve(RLN) is the most common iatrogenic cause of vocal cord paralysis. Identification and preservation of the BLNs and meticulous technique can siginificantly decrease the incidence of this complication. We experienced one case of NRRLN in a patient with the parathyroid adenoma. During the dissection, there was no branch to be considered as RLN in tracheoesophageal groove. While searching for the RLN, We found a white structure coursing horizontally at the level of cricoid cartilage directly arising from the vagus nerve in the carotid sheath. That structure was nonrecurrent recurrent laryngeal nerve(NRRLN) and NRRLNs are exceedingly rare. Awareness of the possibility of NRRLN will prevent the surgeon from accidentally severing one if it is encountered during surgery.

• Communications for Statistical Applications and Methods
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• 제27권1호
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• pp.37-46
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• 2020

Recurrent event data frequently occur in clinical studies, demography, engineering reliability and so on (Cook and Lawless, The Statistical Analysis of Recurrent Events, Springer, 2007). Sometimes, two or more different but related type of recurrent events may occur simultaneously. In this study, our interest is to estimate the covariate effect on bivariate recurrent event times with zero inflations. Such zero inflation can be related with susceptibility. In the context of bivariate recurrent event data, furthermore, such susceptibilities may be different according to the type of event. We propose a joint model including both two intensity functions and two cure rate functions. Bivariate frailty effects are adopted to model the correlation between recurrent events. Parameter estimates are obtained by maximizing the likelihood derived under a piecewise constant hazard assumption. According to simulation results, the proposed method brings unbiased estimates while the model ignoring cure rate models gives underestimated covariate effects and overestimated variance estimates. We apply the proposed method to a set of bivariate recurrent infection data in a study of child patients with leukemia.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.478-481
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• 1999

In this paper, we could analyze and compare with the generalized Recurrent neural networks and the Recurrent neural networks applying the fuzzy. The total system is digitalized in order to be filtering the image, and the fuzzy is applied to the generalized Recurrent in order to be fast the operation speed. So the fuzzified Recurrent neural networks are completely removed to the included noise in the image, and could converge on a certain value as controlling the weight and iteration frequency corresponding to the desired target value. Also, that values are compared and analysed using MSE and PSNR. When applying to the image which is included to the noise in the generalized Recurrent and the Recurrent applying the fuzzy, the Recurrent applying the fuzzy is shown the superiority at the noise and the fixed convergence part through MSE and PSNR in the computer simulations.

• Kyungpook Mathematical Journal
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• 제49권4호
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• pp.779-788
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• 2009

In this paper we studied generalized ${\phi}$-recurrent and generalized concircular ${\phi}$-recurrent LP-Sasakian manifolds.

• 충청수학회지
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• 제24권4호
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• pp.863-868
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• 2011

The purpose of this paper is to study the orbit behaviours near almost periodic points. We introduce notions of uniformly recurrent and u-recurrent points and investigate some relationships between these properties.

• Journal of applied mathematics & informatics
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• 제37권3_4호
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• pp.251-257
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• 2019

We study the orbit behaviours of recurrent, uniformly recurrent and Poisson stable points. we give conditons that a point is to be recurrent or uniformly recurrent by analyzing the behaviours of their orbits. Also, we study dynamical properties of equicontinuous points and points of characteristic $0^+$.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제24권2호
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• pp.53-68
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• 2017

The object of the present paper is to study generalized Z-recurrent manifolds. Some geometric properties of generalized Z-recurrent manifolds have been studied under certain curvature conditions. Finally, we give an example of a generalized Z-recurrent manifold.