• 제목/요약/키워드: Orthogonal series

검색결과 102건 처리시간 0.031초

Identification of System from Generalized Orthogonal Basis Function Expansions

  • Bae, Chul-Min;Wada, Kiyoshi
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.26.1-26
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    • 2001
  • In this paper, we will expand and generalize the orthogonal functions as basis functions for dynamical system representations. The orthogonal functions can be considered as generalizations of, for example, the pulse functions, Laguerre functions, and Kautz functions, and give rise to an alternative series expansion of rational transfer functions. It is shown row we can exploit these generalized basis functions to increase the speed of convergence in a series expansion. The set of Kautz functions is discussed in detail and, using the power-series equivalence, the truncation error is obtained. And so we will present the influence of noises to use Kautz function on the identification accuracy.

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Spatial extrapolation of pressure time series on low buildings using proper orthogonal decomposition

  • Chen, Yingzhao;Kopp, Gregory A.;Surry, David
    • Wind and Structures
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    • 제7권6호
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    • pp.373-392
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    • 2004
  • This paper presents a methodology for spatial extrapolation of wind-induced pressure time series from a corner bay to roof locations on a low building away from the corner through the application of proper orthogonal decomposition (POD). The approach is based on the concept that pressure time series in the far field can be approximated as a linear combination of a series of modes and principal coordinates, where the modes are extracted from the full roof pressure field of an aerodynamically similar building and the principal coordinates are calculated from data at the leading corner bay only. The reliability of the extrapolation for uplift time series in nine bays for a cornering wind direction was examined. It is shown that POD can extrapolate reasonably accurately to bays near the leading corner, given the first three modes, but the extrapolation degrades further from the corner bay as the spatial correlations decrease.

M-ary Bi-orthogonal Modulation UWB with Narrowband Interference Suppression Capability

  • Zhang, Wei-Hua;Shen, Han-Bing;Joo, Jong-Ok;Kwak, Kyung-Sup
    • ETRI Journal
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    • 제30권1호
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    • pp.161-163
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    • 2008
  • An M-ary bi-orthogonal modulation scheme for ultra-wideband (UWB) systems capable of narrowband interference (NBI) suppression is proposed in this letter. We utilize a set of bi-orthogonal pulse series to achieve NBI suppression. Through analysis and simulation, we verify that the proposed scheme can suppress NBIs effectively.

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Characterization of Surface Quality in Orthogonal Cutting of Glass Fiber Reinforced Plastics

  • Choi Gi Heung
    • International Journal of Safety
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    • 제3권1호
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    • pp.1-5
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    • 2004
  • This study discusses frequency analysis based on autoregressive (AR) time series model, and the characterization of surface quality in orthogonal cutting of a fiber-matrix composite materials. A sparsely distributed idealized composite material, namely a glass reinforced polyester (GFRP) was used as workpiece. Analysis method employs a force sensor and the signals from the sensor are processed using AR time series model. The experimental correlations between the fiber pull-out and AR model coefficients are then established.

Identification Using Orthonormal Functions

  • Bae, Chul-Min;Wada, Kiyoshi;Imai, Jun
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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    • pp.285-288
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    • 1998
  • A least-squares identification method is studied that estimates a finite number of coefficients in the series expansion of a transfer function, where the expansion is in terms of recently introduced generalized basis functions, We will expand and generalize the orthogonal functions as basis functions for dynamical system representations. To this end, use is made of balanced realizations as inner transfer functions. The orthogonal functions can be considered as generalizations of, for example, the pulse functions, Laguerre functions, and Kautz functions, and give rise to an alternative series expansion of rational transfer functions. We show that the Laplace transform of the expansion for some sets$\Psi_{\kappa}(Z)$ is equivalent to a series expansion . Techniques based on this result are presented for obtaining the coefficients $c_{n}$ as those of a series. One of their important properties is that, if chosen properly, they can substantially increase the speed of convergence of the series expansion. This leads to accurate approximate models with only a few coefficients to be estimated. The set of Kautz functions is discussed in detail and, using the power-series equivalence, the truncation error is obtained.

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CONVERGENCE RATE OF HYBRID SAMPLING SERIES ASSOCIATED WITH WAVELETS

  • Shim, Hong-Tae;Kwon, Joong-Sung
    • Journal of applied mathematics & informatics
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    • 제14권1_2호
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    • pp.267-275
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    • 2004
  • While the convergence of the classical Fourier series has been well known, the rate of its convergence is not well acknowledged. The results regarding the rate of convergence of the Fourier series and wavelet expansions can be found in the book of Walter[5]. In this paper, we give the rate of convergence of hybrid sampling series associated with orthogonal wavelets.

HYBRID SAMPLING SERIES ASSOCIATED WITH ORTHOGONAL WAVELETS AND GIBBS PHENOMENON

  • Shim, Hong-Tae;Gilbert G. Walter
    • Journal of applied mathematics & informatics
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    • 제12권1_2호
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    • pp.199-209
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    • 2003
  • When a sampling theorem holds in wavelet subspaces, sampling expansions can be a good approximation to projection expansions. Even when the sampling theorem does not hold, the scaling function series with the usual coefficients replaced by sampled function values may also be a good approximation to the projection. We refer to such series as hybrid sampling series. For this series, we shall investigate the local convergence and analyze Gibbs phenomenon.

시계열 섭동 모델링 알고리즘 : 운전자 프로그래밍과 양자역학 섭동이론의 통합 (Time Series Perturbation Modeling Algorithm : Combination of Genetic Programming and Quantum Mechanical Perturbation Theory)

  • 이금용
    • 정보처리학회논문지B
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    • 제9B권3호
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    • pp.277-286
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    • 2002
  • 양자역학 섭동이론과 유전자프로그래밍(GP) 기법을 접목시킴으로써 실세계(Real-world)에서 발생하는 카오스 시계열에 대하여 수학모델을 구축, 예측하기 위한 새로운 알고리즘을 개발하였다. 시계열 분석과 양자역학 파동방정식의 해를 구하는 섭동이론과의 절차적 유사성을 논하고, 이것을 GP로 구현하는 전형적 접근방안을 제시한다. 함수집합(Function Set)으로서 직교함수(Orthogonal Functions)를 이용하고 병렬 집단을 사용하는 GP를 이용하여 원 시계열에 대한 초기 수학모델을 구하고, 원 시계열 데이터로부터 모델의 평가값을 뺀 나머지로 구성되는 잔여 시계열에 대하여 다시 GP를 적용하는 과정을 일정한 종료조건이 충족될 때가지 반복함으로써 실세계 카오스 시계열에 대한 정확성 높은 수학모델을 구축하는데 성공하였다. 타 방법론과의 비교와 향후 해결과제에 대하여도 소개한다.