• 제목/요약/키워드: Wavelet basis

검색결과 143건 처리시간 0.024초

A mesh-free analysis method of structural elements of engineering structures based on B-spline wavelet basis function

  • Chen, Jianping;Tang, Wenyong;Huang, Pengju;Xu, Li
    • Structural Engineering and Mechanics
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    • 제57권2호
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    • pp.281-294
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    • 2016
  • The paper is devoted to study a mesh-free analysis method of structural elements of engineering structures based on B-spline Wavelet Basis Function. First, by employing the moving-least square method and the weighted residual method to solve the structural displacement field, the control equations and the stiffness equations are obtained. And then constructs the displacement field of the structure by using the m-order B-spline wavelet basis function as a weight function. In the end, the paper selects the plane beam structure and the structure with opening hole to carry out numerical analysis of deformation and stress. The Finite Element Method calculation results are compared with the results of the method proposed, and the calculation results of the relative error norm is compared with Gauss weight function as weight function. Therefore, the clarification verified the validity and accuracy of the proposed method.

REMARKS ON KERNEL FOR WAVELET EXPANSIONS IN MULTIDIMENSIONS

  • Shim, Hong-Tae;Kwon, Joong-Sung
    • Journal of applied mathematics & informatics
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    • 제27권1_2호
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    • pp.419-426
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    • 2009
  • In expansion of function by special basis functions, properties of expansion kernel are very important. In the Fourier series, the series are expressed by the convolution with Dirichlet kernel. We investigate some of properties of kernel in wavelet expansions both in one and higher dimensions.

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BIORTHOGONAL WAVELET DERIVATIVES

  • Kwon, Soon-Geol
    • Journal of applied mathematics & informatics
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    • 제9권1호
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    • pp.423-431
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    • 2002
  • In this paper, we find $n^{th}$ order wavelet derivatives of a sufficiently smooth function using biorthogonal wavelet bases and derive the order of convergence of the $n^{th}$ order wavelet derivatives.

Design of the Structure for Scaling-Wavelet Neural Network Using Genetic Algorithm (유전 알고리즘을 이용한 스케일링-웨이블릿 복합 신경회로망 구조 설계)

  • 김성주;서재용;연정흠;김성현;전홍태
    • Proceedings of the IEEK Conference
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    • 대한전자공학회 2001년도 하계종합학술대회 논문집(3)
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    • pp.25-28
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    • 2001
  • RBFN has some problem that because the basis function isn't orthogonal to each others the number of used basis function goes to big. In this reason, the Wavelet Neural Network which uses the orthogonal basis function in the hidden node appears. In this paper, we propose the composition method of the actual function in hidden layer with the scaling function which can represent the region by which the several wavelet can be represented. In this method, we can decrease the size of the network with the pure several wavelet function. In addition to, when we determine the parameters of the scaling function we can process rough approximation and then the network becomes more stable. The other wavelets can be determined by the global solutions which is suitable for the suggested problem using the genetic algorithm and also, we use the back-propagation algorithm in the learning of the weights. In this step, we approximate the target function with fine tuning level. The complex neural network suggested In this paper is a new structure and important simultaneously in the point of handling the determination problem in the wavelet initialization.

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Application of neural networks and an adapted wavelet packet for generating artificial ground motion

  • Asadi, A.;Fadavi, M.;Bagheri, A.;Ghodrati Amiri, G.
    • Structural Engineering and Mechanics
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    • 제37권6호
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    • pp.575-592
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    • 2011
  • For seismic resistant design of critical structures, a dynamic analysis, either response spectrum or time history is frequently required. Owing to the lack of recorded data and the randomness of earthquake ground motion that may be experienced by structure in the future, usually it is difficult to obtain recorded data which fit the requirements (site type, epicenteral distance, etc.) well. Therefore, the artificial seismic records are widely used in seismic designs, verification of seismic capacity and seismic assessment of structures. The purpose of this paper is to develop a numerical method using Artificial Neural Network (ANN) and wavelet packet transform in best basis method which is presented for the decomposition of artificial earthquake records consistent with any arbitrarily specified target response spectra requirements. The ground motion has been modeled as a non-stationary process using wavelet packet. This study shows that the procedure using ANN-based models and wavelet packets in best-basis method are applicable to generate artificial earthquakes compatible with any response spectra. Several numerical examples are given to verify the developed model.

ECG Compression Structure Design Using of Multiple Wavelet Basis Functions (다중웨이브렛 기저함수를 이용한 심전도 압축구조설계)

  • Kim Tae-hyung;Kwon Chang-Young;Yoon Dong-Han
    • Journal of the Korea Institute of Information and Communication Engineering
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    • 제9권3호
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    • pp.467-472
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    • 2005
  • ECG signals are recorded for diagnostic purposes in many clinical situations. Also, In order to permit good clinical interpretation, data is needed at high resolutions and sampling rates. Therefore In this paper, we designed to compression structure using multiple wavelet basis function(SWBF) and compared to single wavelet basis function(SWBF) and discrete cosine transform(DCT). For experience objectivity, Simulation was performed using the arrhythmia data with sampling frequency 360Hz, resolution lIbit at MIT-BIH database. An estimate of performance estimate evaluate the reconstruction error. Consequently compression structure using MWBF has high performance result.

Performance of Wavelet Packet Multicarrier Modulation Systems with Narrowband Interference (웨이블릿 패킷 다중반송파 변조 시스템의 협대역 간섭에 대한 성능)

  • Won, Yu-Jun;Seo, Bo-Seok
    • The Journal of the Korea Contents Association
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    • 제8권4호
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    • pp.79-85
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    • 2008
  • These days, orthogonal frequency division multiplexing (OFDM) transmission method is widely used for broadband communication systems. The OFDM, which uses sine waves as orthogonal basis functions, is one of the orthogonal waveform modulation techniques. In this paper, we investigate a wavelet packet modulation method which uses wavelet packets instead of sine waves as the basis functions. The wavelet packets may have different patterns in two dimensional time-frequency domain, and we can design the packets appropriate for the channel environments with much flexibility. In this paper, we investigate the characteristics of the wavelet packet modulation as one of the multicarrier modulation methods, And we illustrate by simulations that narrowband interference can be reduced effectively by control the bandwidth of the wavelet packets.

Analysis and Compression of Spun-yarn Density Profiles using Adaptive Wavelets

  • Kim, Joo-Yong
    • Textile Coloration and Finishing
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    • 제18권5호
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    • pp.88-93
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    • 2006
  • A data compression system has been developed by combining adaptive wavelets and optimization technique. The adaptive wavelets were made by optimizing the coefficients of the wavelet matrix. The optimization procedure has been performed by criteria of minimizing the reconstruction error. The resulting adaptive basis outperformed such conventional basis as Daubechies-5 by 5-10%. It was also shown that the yarn density profiles could be compressed by over 95% without a significant loss of information.

Analysis of Stationary Time Series Using Wavelet Transform (Wavelet 변환을 이용한 정상 시계열 데이터 해석에 관한 연구)

  • Lee, Joon-Tark;Choi, Woo-Jin;Kim, Tae-Hong
    • Proceedings of the KIEE Conference
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    • 대한전기학회 1999년도 하계학술대회 논문집 B
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    • pp.969-971
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    • 1999
  • Wavelet analysis is applying to many fields such as the time-frequency localization of a time series and a time varying data. In this paper, a statistical testing based Wavelet power spectrum analysis for the stationary Nino3 Sea Surface Temperature(SST) data was executed. Specially, the 95% confidence level for SST was effective in searching the periods of El-Nino using various wavelet basis functions.

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Similar Patterns for Semi-blind Watermarking

  • Cho, Jae-Hyun
    • Journal of information and communication convergence engineering
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    • 제2권4호
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    • pp.251-255
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    • 2004
  • In this paper, we present a watermarking scheme based on the DWT (Discrete Wavelet Transform) and the ANN (Artificial Neural Network) to ensure the copyright protection of the digital images. The problem to embed watermark is not clear to select important coefficient in the watermarking. We used the RBF (Radial-Basis Function) to solve the problem. We didn't apply the whole wavelet coefficients, but applied to only the wavelet coefficients in the selected node. Using the ANN, although even the watermark casting process and watermark verification process are in public, nobody knows the location of embedding watermark except of authorized user. As the result, the watermark is good at the strength test-filtering, geometric transform and etc.