• Title/Summary/Keyword: exactness

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CERTAIN GENERALIZATIONS OF G-SEQUENCES AND THEIR EXACTNESS

  • Lee, Kee-Young;Woo, Moo-Ha;Zhao, Xuezhi
    • Bulletin of the Korean Mathematical Society
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    • v.45 no.1
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    • pp.119-131
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    • 2008
  • In this paper, we generalize the Gottlieb groups and the related G-sequence of those groups, and present some sufficient conditions to ensure the exactness or non-exactness of G-sequences at some terms. We also give some applications of the exactness or non-exactness of G-sequences. Especially, we show that the non-exactness of G-sequences implies the non-triviality of homotopy groups of some function spaces.

EXACTNESS OF COCHAIN COMPLEXES VIA ADDITIVE FUNCTORS

  • Campanini, Federico;Facchini, Alberto
    • Communications of the Korean Mathematical Society
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    • v.35 no.4
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    • pp.1075-1085
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    • 2020
  • We investigate the relation between the notion of e-exactness, recently introduced by Akray and Zebary, and some functors naturally related to it, such as the functor P : Mod-R → Spec(Mod-R), where Spec(Mod-R) denotes the spectral category of Mod-R, and the localization functor with respect to the singular torsion theory.

Personalized Movie Recommendation System Combining Data Mining with the k-Clique Method

  • Vilakone, Phonexay;Xinchang, Khamphaphone;Park, Doo-Soon
    • Journal of Information Processing Systems
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    • v.15 no.5
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    • pp.1141-1155
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    • 2019
  • Today, most approaches used in the recommendation system provide correct data prediction similar to the data that users need. The method that researchers are paying attention and apply as a model in the recommendation system is the communities' detection in the big social network. The outputted result of this approach is effective in improving the exactness. Therefore, in this paper, the personalized movie recommendation system that combines data mining for the k-clique method is proposed as the best exactness data to the users. The proposed approach was compared with the existing approaches like k-clique, collaborative filtering, and collaborative filtering using k-nearest neighbor. The outputted result guarantees that the proposed method gives significant exactness data compared to the existing approach. In the experiment, the MovieLens data were used as practice and test data.

ON THE ASYMPTOTIC EXACTNESS OF AN ERROR ESTIMATOR FOR THE LOWEST-ORDER RAVIART-THOMAS MIXED FINITE ELEMENT

  • Kim, Kwang-Yeon
    • Korean Journal of Mathematics
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    • v.21 no.3
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    • pp.293-304
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    • 2013
  • In this paper we analyze an error estimator for the lowest-order triangular Raviart-Thomas mixed finite element which is based on solution of local problems for the error. This estimator was proposed in [Alonso, Error estimators for a mixed method, Numer. Math. 74 (1996), 385{395] and has a similar concept to that of Bank and Weiser. We show that it is asymptotically exact for the Poisson equation if the underlying triangulations are uniform and the exact solution is regular enough.

ASYMPTOTIC EXACTNESS OF SOME BANK-WEISER ERROR ESTIMATOR FOR QUADRATIC TRIANGULAR FINITE ELEMENT

  • Kim, Kwang-Yeon;Park, Ju-Seong
    • Bulletin of the Korean Mathematical Society
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    • v.57 no.2
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    • pp.393-406
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    • 2020
  • We analyze a posteriori error estimator for the conforming P2 finite element on triangular meshes which is based on the solution of local Neumann problems. This error estimator extends the one for the conforming P1 finite element proposed in [4]. We prove that it is asymptotically exact for the Poisson equation when the underlying triangulations are mildly structured and the solution is smooth enough.

An Exactness Analysis for Damage Cause of Large-Capacitor and High-Voltage Motor (대용량 고압모터 고장원인 정밀 분석)

  • Hong, Sung-Taek;Lee, Eun-Chun;Shin, Gang-Wook
    • Proceedings of the KIEE Conference
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    • 2000.11b
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    • pp.259-261
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    • 2000
  • This paper demonstrates the trip of high-voltage motor(6.6kV 4,600Hp). To analyze the causes of damage in motors. exactness analysis of electricity system, analysis inspection of motor and voltage quality analysis fiery development were investigated. This result propose to improvement system and repair method.

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A POSTERIORI ERROR ESTIMATORS FOR THE STABILIZED LOW-ORDER FINITE ELEMENT DISCRETIZATION OF THE STOKES EQUATIONS BASED ON LOCAL PROBLEMS

  • KIM, KWANG-YEON
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.21 no.4
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    • pp.203-214
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    • 2017
  • In this paper we propose and analyze two a posteriori error estimators for the stabilized $P_1/P_1$ finite element discretization of the Stokes equations. These error estimators are computed by solving local Poisson or Stokes problems on elements of the underlying triangulation. We establish their asymptotic exactness with respect to the velocity error under certain conditions on the triangulation and the regularity of the exact solution.

SUPERCONVERGENCE AND POSTPROCESSING OF EQUILIBRATED FLUXES FOR QUADRATIC FINITE ELEMENTS

  • KWANG-YEON KIM
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.27 no.4
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    • pp.245-271
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    • 2023
  • In this paper we discuss some recovery of H(div)-conforming flux approximations from the equilibrated fluxes of Ainsworth and Oden for quadratic finite element methods of second-order elliptic problems. Combined with the hypercircle method of Prager and Synge, these flux approximations lead to a posteriori error estimators which provide guaranteed upper bounds on the numerical error. Furthermore, we prove some superconvergence results for the flux approximations and asymptotic exactness for the error estimator under proper conditions on the triangulation and the exact solution. The results extend those of the previous paper for linear finite element methods.