The three-dimensional biorthogonal multiresolution time-domain (Bi-MRTD) method is presented for both free-space and half-space scattering problems. The perfectly matched layer (PML) is used as an absorbing boundary condition. It has been shown that improved numerical-dispersion properties can be obtained with the use of smooth, compactly supported wavelet functions as the basis, whereas we employ the Cohen-Daubechies-Fouveau (CDF) biorthogonal wavelets. When a CDF-wavelet expansion is used, the spatial-sampling rate can be reduced considerably compared with that of the conventional finite-difference time-domain (FDTD) method, implying that larger targets can be simulated without sacrificing accuracy. We implement the Bi-MRTD on a cluster of allocated-memory machines, using the message-passing interface (MPI), such that very large targets can be modeled. Numerical results are compared with analytical ones and with those obtained by use of the traditional FDTD method.
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http://dx.doi.org/10.1364/josaa.20.000844 | DOI Listing |
Symmetry (Basel)
December 2017
Department of Mathematics, University of Vienna, Oskar-Morgenstern-Platz 1, A-1090 Vienna, Austria.
In this paper, the stability of translation-invariant spaces of distributions over locally compact groups is stated as boundedness of synthesis and projection operators. At first, a characterization of the stability of spline-type spaces is given, in the standard sense of the stability for shift-invariant spaces, that is, linear independence characterizes lower boundedness of the synthesis operator in Banach spaces of distributions. The constructive nature of the proof for Theorem 2 enabled us to constructively realize the biorthogonal system of a given one.
View Article and Find Full Text PDFSheng Wu Yi Xue Gong Cheng Xue Za Zhi
June 2015
We proposed a multi-resolution-wavelet-transform based method to extract brainstem auditory evoked potential (BAEP) from the background noise and then to identify its characteristics correctly. Firstly we discussed the mother wavelet and wavelet transform algorithm and proved that bi-orthogonal wavelet bior5. 5 and stationary discrete wavelet transform (SWT) were more suitable for BAEP signals.
View Article and Find Full Text PDFJ Digit Imaging
June 2013
Biomedical Instrumentation Laboratory, Department of Electrical Engineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India 247667.
A system to characterize normal liver, cirrhotic liver and hepatocellular carcinoma (HCC) evolved on cirrhotic liver is proposed in this paper. The study is performed with 56 real ultrasound images (15 normal, 16 cirrhotic and 25 HCC liver images) taken from 56 subjects. A total of 180 nonoverlapping regions of interest (ROIs), i.
View Article and Find Full Text PDFTalanta
June 2010
Faculty of Chemistry, Azad University, North Tehran Branch, Tehran, Iran.
In present paper, continuous wavelet transform as well as first and second derivative spectrophotometry methods are proposed for simultaneous quantitative analysis of triamterene and hydrochlorothiazide without the time-consuming extraction step. In the wavelet transform method, different wavelet families were tested and subsequently coiflets wavelet family (coif1) and reverse biorthogonal wavelet family (rbio 2.8) were selected and applied under the optimal conditions for simultaneous analysis.
View Article and Find Full Text PDFAnnu Int Conf IEEE Eng Med Biol Soc
March 2010
Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
Cardiac arrest (CA) can produce complex changes in somatosensory evoked potentials (SSEPs). Somatosensory evoked potentials (SSEPs) indicate the intactness of somatosensory pathways and are commonly used for brain function monitoring during surgeries. Multiresolution biorthogonal wavelet analysis was applied to SSEPs recorded during established CA experiments and post-CA long-term recovery periods in rats.
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