scholarly journals Reply to the Comments of J. C. Dooley on “Analysis of a Magnetic Sphere Using the Fourier Transform: a New Approach”

1990 ◽  
Vol 21 (3-4) ◽  
pp. 217-218
Author(s):  
N. L. Mohan ◽  
N. B. R. Prasad ◽  
S. V. Seshagiri Rao ◽  
V. L. S. Bhimasankaram
Keyword(s):  
Fourier Transform ◽  
New Approach ◽  
The Fourier Transform ◽  
Magnetic Sphere

Analysis of a Magnetic Sphere Using the Fourier Transform: A New Approach

1982 ◽  
Vol 13 (2) ◽  
pp. 35-40 ◽  
Author(s):  
N. L. Mohan ◽  
N. B. R. Prasad ◽  
S. V. Seshagari Rao ◽  
V. L. S. Bhimasankaram
Keyword(s):  
Fourier Transform ◽  
New Approach ◽  
The Fourier Transform ◽  
Magnetic Sphere

scholarly journals A New Application Methodology of the Fourier Transform for Rational Approximation of the Complex Error Function

2016 ◽  
Vol 8 (1) ◽  
pp. 14 ◽  
Author(s):  
S. M. Abrarov ◽  
B. M. Quine
Keyword(s):  
Fourier Transform ◽  
Rational Approximation ◽  
Error Function ◽  
Practical Importance ◽  
Exponential Functions ◽  
New Approach ◽  
Practical Applications ◽  
Input Parameters ◽  
The Fourier Transform

<p>This paper presents a new approach in application of the Fourier transform to the complex error function resulting in an efficient rational approximation. Specifically, the computational test shows that with only $17$ summation terms the obtained rational approximation of the complex error function provides accuracy ${10^{ - 15}}$ over the most domain of practical importance $0 \le x \le 40,000$ and ${10^{ - 4}} \le y \le {10^2}$ required for the HITRAN-based spectroscopic applications. Since the rational approximation does not contain trigonometric or exponential functions dependent upon the input parameters $x$ and $y$, it is rapid in computation. Such an example demonstrates that the considered methodology of the Fourier transform may be advantageous in practical applications.</p>

scholarly journals IDENTIFICATION OF BINARY CELLULAR AUTOMATA FROM SPATIO-TEMPORAL BINARY PATTERNS USING A FOURIER REPRESENTATION

2007 ◽  
Vol 17 (06) ◽  
pp. 1985-1996 ◽  
Author(s):  
L. Z. GUO ◽  
S. A. BILLINGS
Keyword(s):  
Fourier Transform ◽  
Cellular Automata ◽  
Least Squares ◽  
Boolean Functions ◽  
Multilinear Polynomial ◽  
Polynomial Representation ◽  
New Approach ◽  
Spatio Temporal ◽  
The Fourier Transform ◽  
Robust To Noise

The identification of binary cellular automata from spatio-temporal binary patterns is investigated in this paper. Instead of using the usual Boolean or multilinear polynomial representation, the Fourier transform representation of Boolean functions is employed in terms of a Fourier basis. In this way, the orthogonal forward regression least-squares algorithm can be applied directly to detect the significant terms and to estimate the associated parameters. Compared with conventional methods, the new approach is much more robust to noise. Examples are provided to illustrate the effectiveness of the proposed approach.

A NANOSTRUCTURED POLYMORPH OF μ-OXOBIS(PHTHALOCYANINATOIRON(III)) STUDIED BY ANGULAR AND ENERGY DISPERSIVE X-RAY DIFFRACTION

NANO ◽  
2007 ◽  
Vol 02 (02) ◽  
pp. 121-128 ◽  
Author(s):  
ROBERTO MATASSA ◽  
PAOLO BALLIRANO ◽  
MARIA PIA DONZELLO ◽  
CLAUDIO ERCOLANI ◽  
CLAUDIA SADUN ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Rietveld Method ◽  
Energy Dispersive ◽  
Structural Function ◽  
X Ray Diffraction ◽  
New Approach ◽  
X Ray ◽  
The Fourier Transform

A new approach of X-ray diffraction was used to investigate the nanostructured μ-Oxo(2) polymorph of μ-oxo-bis(phthalocyaninatoiron(III)), [ PcFe – O – FePc ]. The packing of the dinuclear units was determined by the Rietveld method on Angular Dispersive X-ray Diffraction (ADXD) data, whereas the intramolecular geometry was optimized by Energy Dispersive X-ray Diffraction (EDXD) exploiting the peculiar strength of those techniques. The dimension of the nanoparticles was estimated from the Fourier transform of the EDXD experimental structural function.

Plane wave diffraction by two parallel overlapped thick semiinfinite impedance plates

2000 ◽  
Vol 77 (11) ◽  
pp. 873-891
Author(s):  
F Birbir ◽  
A Büyükaksoy
Keyword(s):  
Fourier Transform ◽  
Plane Waves ◽  
Separation Distance ◽  
Mode Matching ◽  
Matching Method ◽  
New Approach ◽  
Time Harmonic ◽  
Plate Separation ◽  
The Fourier Transform ◽  
Plane Wave Diffraction

A new approach consisting of employing the mode matching method inconjunction with the Fourier transform technique is used to analyse thediffraction of time harmonic plane waves by two parallel overlapped thickimpedance half-planes. The problem is formulated as a pair of uncoupledmodified Wiener-Hopf equations and solved approximately. Numerical resultsillustrating the effects of various parameters such as wall thickness, plateto plate separation distance, wall impedance, etc. on the diffractionphenomenon are presented.PACS No.: 41.20jb

scholarly journals Strain Sensitivity Enhancement of Broadband Ultrasonic Signals in Plates Using Spectral Phase Filtering

2021 ◽  
Vol 11 (6) ◽  
pp. 2582
Author(s):  
Lucas M. Martinho ◽  
Alan C. Kubrusly ◽  
Nicolás Pérez ◽  
Jean Pierre von der Weid
Keyword(s):  
Fourier Transform ◽  
Guided Waves ◽  
Strain Level ◽  
Energy Concentration ◽  
Short Time Fourier Transform ◽  
Time Frequency ◽  
Frequency Representation ◽  
The Fourier Transform ◽  
Short Time ◽  
Sensitivity Gain

The focused signal obtained by the time-reversal or the cross-correlation techniques of ultrasonic guided waves in plates changes when the medium is subject to strain, which can be used to monitor the medium strain level. In this paper, the sensitivity to strain of cross-correlated signals is enhanced by a post-processing filtering procedure aiming to preserve only strain-sensitive spectrum components. Two different strategies were adopted, based on the phase of either the Fourier transform or the short-time Fourier transform. Both use prior knowledge of the system impulse response at some strain level. The technique was evaluated in an aluminum plate, effectively providing up to twice higher sensitivity to strain. The sensitivity increase depends on a phase threshold parameter used in the filtering process. Its performance was assessed based on the sensitivity gain, the loss of energy concentration capability, and the value of the foreknown strain. Signals synthesized with the time–frequency representation, through the short-time Fourier transform, provided a better tradeoff between sensitivity gain and loss of energy concentration.

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