• 제목/요약/키워드: approximate approach

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Computational Methods for Detection of Multiple Outliers in Nonlinear Regression

  • Myung-Wook Kahng
    • Communications for Statistical Applications and Methods
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    • 제3권2호
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    • pp.1-11
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    • 1996
  • The detection of multiple outliers in nonlinear regression models can be computationally not feasible. As a compromise approach, we consider the use of simulated annealing algorithm, an approximate approach to combinatorial optimization. We show that this method ensures convergence and works well in locating multiple outliers while reducing computational time.

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A numerical approach for assessing internal pressure capacity at liner failure in the expanded free-field of the prestressed concrete containment vessel

  • Woo-Min Cho;Seong-Kug Ha;SaeHanSol Kang;Yoon-Suk Chang
    • Nuclear Engineering and Technology
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    • 제55권10호
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    • pp.3677-3691
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    • 2023
  • Since containment building is the major shielding structure to ensure safety of nuclear power plant, the structural behavior and ultimate pressure capacity of containments must be studied in depth. This paper addresses ambiguous issue of determining free-field position for liner failure by suggesting an expanded free-field region and comparing internal pressure capacities obtained by test data, conservative assumption and suggested free-field region. For this purpose, a practical approach to determine the free-field position for the evaluation of liner tearing is carried out. The maximum principal strain histories versus internal pressure capacities among different free-field positions at various azimuths and elevations are compared with those at the equipment hatch as a conservative assumption. The comparison shows that there are considerable differences in the internal pressure capacity at liner failure within the expanded free-field region compared to the vicinity of the equipment hatch. Additionally, this study proposes an approximate correlation with conservative factors by considering the expanded free-field ranges and material characteristics to determine realistic failure criteria for liner. The applicability of the proposed correlation is demonstrated by comparing the internal pressure capacities of full-scale containment buildings following liner failure criteria according to RG 1.216 and an approximate correlation.

Some new similarity based approaches in approximate reasoning and their applications to pattern recognition

  • Swapan Raha;Nikhil R. Pal;Ray, Kumar-Sankar
    • 한국지능시스템학회:학술대회논문집
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    • 한국퍼지및지능시스템학회 1998년도 The Third Asian Fuzzy Systems Symposium
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    • pp.719-724
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    • 1998
  • This paper presents a systematic developement of a formal approach to inference in approximate reasoning. We introduce some measures of similarity and discuss their properties. Using the concept of similarity index we formulate two methods for inferring from vague knowledge. In order to illustrate the effectiveness of the proposed technique we use it to develop a vowel recognition system.

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On Approximate Prediction Intervals for Support Vector Machine Regression

  • 황창하;석경하;조대현
    • Journal of the Korean Data and Information Science Society
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    • 제13권2호
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    • pp.65-75
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    • 2002
  • The support vector machine (SVM), first developed by Vapnik and his group at AT &T Bell Laboratories, is being used as a new technique for regression and classification problems. In this paper we present an approach to estimating approximate prediction intervals for SVM regression based on posterior predictive densities. Furthermore, the method is illustrated with a data example.

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Significance of rigorous fluid-foundation interaction in dynamic analysis of concrete gravity dams

  • Lotfi, Vahid
    • Structural Engineering and Mechanics
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    • 제21권2호
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    • pp.137-150
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    • 2005
  • Dynamic analysis of dam-reservoir-foundation system is usually carried out by employing a simplified and approximate one-dimensional model to account for fluid-foundation interaction. The approximation introduced on this basis is examined thoroughly in this paper by comparing the method with the rigorous approach. It is concluded that the errors due to approximate method could be very significant both for horizontal and vertical ground motions.

A Bayesian Test Criterion for the Multivariate Behrens-Fisher Problem

  • Kim, Hea-Jung
    • Journal of the Korean Statistical Society
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    • 제28권1호
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    • pp.107-124
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    • 1999
  • An approximate Bayes criterion for multivariate Behrens-Fisher problem is proposed and examined. Development of the criterion involves derivation of approximate Bayes factor using the imaginary training sample approach introduced by Speigelhalter and Smith (1982). The criterion is designed to develop a Bayesian test, so that it provides an alternative test to other tests based upon asymptotic sampling theory (such as the tests suggested by Bennett(1951), James(1954) and Yao(1965). For the derived criterion, numerical studies demonstrate routine application and give comparisons with the classical tests.

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Semisupervised support vector quantile regression

  • Seok, Kyungha
    • Journal of the Korean Data and Information Science Society
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    • 제26권2호
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    • pp.517-524
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    • 2015
  • Unlabeled examples are easier and less expensive to be obtained than labeled examples. In this paper semisupervised approach is used to utilize such examples in an effort to enhance the predictive performance of nonlinear quantile regression problems. We propose a semisupervised quantile regression method named semisupervised support vector quantile regression, which is based on support vector machine. A generalized approximate cross validation method is used to choose the hyper-parameters that affect the performance of estimator. The experimental results confirm the successful performance of the proposed S2SVQR.

SOBOLEV TYPE APPROXIMATION ORDER BY SCATTERED SHIFTS OF A RADIAL BASIS FUNCTION

  • Yoon, Jung-Ho
    • Journal of applied mathematics & informatics
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    • 제23권1_2호
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    • pp.435-443
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    • 2007
  • An important approach towards solving the scattered data problem is by using radial basis functions. However, for a large class of smooth basis functions such as Gaussians, the existing theories guarantee the interpolant to approximate well only for a very small class of very smooth approximate which is the so-called 'native' space. The approximands f need to be extremely smooth. Hence, the purpose of this paper is to study approximation by a scattered shifts of a radial basis functions. We provide error estimates on larger spaces, especially on the homogeneous Sobolev spaces.

RF-MEMS 스위치용 마이크로 외팔보의 감쇠특성 (Damping Characteristics of a Microcantilever for Radio Frequency-microelectromechanical Switches)

  • 이진우
    • 한국소음진동공학회논문집
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    • 제21권6호
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    • pp.553-561
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    • 2011
  • A theoretical approach is carried out to predict the quality factors of flexible modes of a microcantilever on a squeeze-film. The frequency response function of an inertially-excited microcantilever beam is derived using an Euler-Bernoulli beam theory. The external force due to squeeze-film phenomenon is developed from the Reynolds equation. Slip boundary conditions are employed at the interfaces between the fluid and the structure to consider the gas rarefaction effect, and pressure boundary condition at both ends of fluid analysis region is enhanced to increase the exactness of predicted quality factors. To the end, an approximate equation is derived for the first bending mode of the microcantilever. Using the approximate equation, the quality factors of the second and third bending modes are calculated and compared with experimental results of previously reported work. The comparison shows the feasibility of the current approach.