In this paper we present a convergence analysis for the Nyström method proposed in [Jour. Comput. Phys. 169 pp. 2921-2934, 2001] for the solution of the combined boundary integral equation formulations of sound-soft acoustic scattering problems in three-dimensional space. This fast and efficient scheme combines FFT techniques and a polar change of variables that cancels out the kernel singulari...

This paper presents a very simple implementation of a fluid solver. Our solver is consistent with the equations of fluid flow and produces velocity fields that contain incompressible rotational structures and that dynamically react to user-supplied forces. The solver is specialized for a fluid which wraps around in space. This allows us to take advantage of the Fourier transform which greatly s...

Identification of local anisotropy and determination of principal axes is addressed through different methods that are designed to be tolerant to the non-smooth character of images on the pixel scale. These different tools are validated on various examples, and their performances are compared. The most powerful, robust and accurate method consists in computing the curvature tensor of the auto-c...

Bearing fault diagnosis has been a challenge in the monitoring activities of rotating machinery, and it’s receiving more and more attention. The conventional fault diagnosis methods usually extract features from the waveforms or spectrums of vibration signals in order to realize fault classification. In this paper, a novel feature in the form of images is presented, namely the spectrum images o...

In the past, mathematicians actively used the ability of some people to perform calculations unusually fast. With the advent of computers, there is no longer need for human calculators – even fast ones. However, recently, it was discovered that there exist, e.g., multiplication algorithms which are much faster than standard multiplication. Because of this discovery, it is possible than even fas...

A new method of parametrio ooding at medium output rate is introduoed. The availability of new eleotronio oomponents ohanges the hypotheses assumed in previous studies. A parametrio ooding soheme with medium output rate is rendered feasible for rulebased synthesis, like for voioe-mailing systems. The weak spot in most of the parametrio synthesizers lies in the distinotion made between voioed an...

In this paper we describe the architecture{speci c automatic performance tuning implemented in the UHFFT library. The UHFFT library is an adaptive and portable software library for fast Fourier transforms (FFT).

We calculate the local Fourier transformations for a class of Ql-sheaves. In particular, we verify a conjecture of Laumon and Malgrange ([15] 2.6.3). As an application, we calculate the local monodromy of l-adic hypergeometric sheaves introduced by Katz ([12]). We also discuss the characteristic p analogue of the Turrittin-Levelt Theorem for D-modules. The method used in this paper can be used ...

Figure 1. The spectrum of an input voltage is calculated using an FFT application. (See article inside, page 9.) Figure 2. A butterfly computation is used to perform an FFT for N = 8. (See article inside, page 10.)