• Title, Summary, Keyword: recurrent

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On Quasi-Conformally Recurrent Manifolds with Harmonic Quasi-Conformal Curvature Tensor

  • Shaikh, Absos Ali;Roy, Indranil
    • Kyungpook Mathematical Journal
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    • v.51 no.1
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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.

UNIFORM RECURRENCE IN DYNAMICAL SYSTEMS

  • Koo, Kishik
    • Journal of the Chungcheong Mathematical Society
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    • v.24 no.4
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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.

A study on the fuzzified Diagonal Recurrent Neural Networks for the Image Processing (영상처리를 위한 퍼지화된 대각형 Recurrent 신경망에 관한 연구)

  • 변오성;문성룡
    • Proceedings of the IEEK Conference
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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.

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A Case of NRRL(Non-Recurrent Recurrent Laryngeal Nerve) in a Patient with the Parathyroid Adenoma (부갑상선 선종 수술시 관찰된 비회귀성 반회후두신경 (Non-Recurrent Recurrent Laryngeal Nerve) 1례)

  • 한수진;임재열;박헌이;최홍식
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.11 no.2
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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.

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Analysis of bivariate recurrent event data with zero inflation

  • Kim, Taeun;Kim, Yang-Jin
    • Communications for Statistical Applications and Methods
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    • v.27 no.1
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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.

Sequential Changes in Left Ventricular Systolic Myocardial Deformation Mechanics in Children with Recurrent Kawasaki Disease

  • Kang, Soo Jung;Jin, Bo Kyeong;Hwang, Seo Jung;Kim, Hyo Jin
    • Journal of Cardiovascular Imaging
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    • v.26 no.3
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    • pp.147-154
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    • 2018
  • BACKGROUND: Sequential changes in left ventricular (LV) systolic function over time in patients with recurrent episodes of Kawasaki disease (KD) remain unclear. METHODS: Twenty-five children with recurrent KD were retrospectively studied. Using conventional echocardiographic parameters and myocardial deformation analysis, systolic LV function in children in initial and recurrent KD episodes were compared with separate control groups, comprising 15 controls each. Recurrent KD was defined as occurring at an interval of ${\geq}2$ months between the initial and recurrent episodes. RESULTS: The interval range between initial and recurrent episodes of KD was 3-103 months. In children with KD, 8 (32%) were <1 year of age at the initial episode, 10 (40%) had a recurrence within 1 year of the initial episode, and 4 (16%) and 5 (20%) were intravenous immune globulin nonresponders in initial and recurrent episodes, respectively. In both the initial and recurrent episodes of KD, the mean LV longitudinal peak systolic ${\varepsilon}$ was all within normal range. However, when compared to controls, mean LV longitudinal peak systolic ${\varepsilon}$ was decreased in patients with KD in the acute phases of both the initial and recurrent episodes. When compared to controls, mean LV longitudinal peak systolic ${\varepsilon}$ was decreased in patients with KD in the convalescent phase of the recurrent episodes. CONCLUSIONS: Subclinical decreases in myocardial systolic deformation, as evidenced by decreased LV longitudinal peak systolic ${\varepsilon}$, may persist in children in the convalescent phase of recurrent KD; further studies involving larger numbers of patients may be needed for verification.

RECURRENCE AND STABILITY OF POINTS IN DISCRETE FLOWS

  • KOO, KI-SHIK
    • Journal of applied mathematics & informatics
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    • v.37 no.3_4
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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 $0^+$.

Management of Recurrent Vestibular Schwannomas

  • Kim, Wook-Ha;Park, Chul-Kee;Kim, Dong-Gyu;Jung, Hee-Won
    • Journal of Korean Neurosurgical Society
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    • v.39 no.2
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    • pp.87-91
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    • 2006
  • Objective : Management of recurrent vestibular schwannomas[VS] after microsurgery or radiosurgery is a complicated subject. However, few studies have documented the outcome of recurrent VS. The authorsreviewclinicalexperience of recurrent VS management and analyzed the efficacy of treatment modalities. Methods : Between 1990 and 2002, 293 patients harboring unilateral VS underwent, microsurgery, radiosurgery, microsurgery followed by radiosurgery. Of these, 26 procedures [in 20 patients] were performed to assessed from an increased tumor size by magnetic resonance imaging[MRI]. The mean age of patients with recurred VS was 46.9 years and the mean follow-up period was 68 months. Radiological characteristics were investigated and growth rates of recurred tumors were calculated by measuring changes in tumor diameter on MRI after treatment. Results : MRI characteristics revealed a lobulated contour in 75% and a cyst in 60% of the patients. Only 1 patient showed neither lobulation nor a cyst. The average diameter of the recurrent tumors were 36.9mm. The overall tumor control rate for initial management was 87.4%, 94.7%, and 98.5% for microsurgery, radiosurgery, and microsurgery plus radiosurgery, respectively. However, control rates for recurrent tumors were lower at 85%, 63%, and 80%, respectively. Conclusion : A cystic nature and a lobulated tumor contour are frequent clinical characteristics of recurrent VS. Microsurgery or microsurgery followed by radiosurgery shows little difference in tumor control rate for primary and recurrent VS. However, radiosurgery alone appears to be less beneficial for recurrent VS.