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In this article, we describe the role of time-frequency distributions (TFDs) in array processing. We particularly focus on quadratic TFDs (QTFDs). We demonstrate how these distributions can be properly integrated with the spatial dimension to enhance individual source signal recovery and angular estimation. The framework that enables such integration is referred to as spatial TFD (STFD). We present the important milestones of STFDs that have been reached during the last 15 years. Most importantly, we show that array processing creates new perspectives of QTFDs and defines new roles to the autoterms and cross-terms in both problem formulation and solution. Multisensor configurations, in essence, establish a different paradigm and introduces new challenges that did not exist in a single-sensor time-frequency distribution. [ABSTRACT FROM PUBLISHER]

This paper presents two new time-frequency distributions (TFDs) based on kernels with compact support (KCS) namely the separable (CB) (SCB) and the polynomial CB (PCB) TFDs. The implementation of this family of TFDs follows the method developed for the Cheriet–Belouchrani (CB) TFD. The mathematical properties of these three TFDs are analyzed and their performance is compared to the best classical quadratic TFDs using several tests on multicomponent signals with linear and nonlinear frequency modulation (FM) components including the noise effects. Instead of relying solely on visual inspection of the time-frequency domain plots, comparisons include the time slices' plots and the evaluation of the Boashash–Sucic's normalized instantaneous resolution performance measure that permits to provide the optimized TFD using a specific methodology. In all presented examples, the KCS-TFDs show a significant interference rejection, with the component energy concentration around their respective instantaneous frequency laws yielding high resolution measure values. [ABSTRACT FROM AUTHOR]

This paper deals with fault diagnosis of induction machines based on the discrete wavelet transform. By using the wavelet decomposition, the information on the health of a system can be extracted from a signal over a wide range of frequencies. This analysis is performed in both time and frequency domains. The Daubechies wavelet is selected for the analysis of the stator current. Wavelet components appear to be useful for detecting different electrical faults. In this paper, we will study the problem of broken rotor bars, end-ring segment, and loss of stator phase during operation. [ABSTRACT FROM AUTHOR]

Abstract: In the following work, we propose an assessment of wind potential in Algeria. The purpose of this study is twofold. First, to draw the attention to the important wind potential in the region of Hassi-R’mel . In the previous maps, the wind potential in this region has been underestimated due the fact that it is located between two less windy regions. Second, the actualization of the wind map of Algeria using very recent data stretching from February 2004 to December 2009. This paper is structured in three main parts. First, a stochastic and the cyclic study of the wind behaviors in the site of Hassi-R’mel are proposed. The stochastic study is carried out by fitting the wind speed data to Weibull distribution while the cyclic study is carried out via the use of time–frequency analysis. We have used the time–frequency analyses instead of the traditional Fourier analysis due its ability to follow the spectrum variation with respect to time. As results, it has been found that spectrum wind process enfold many limited interval oscillations. In the second part, we propose to contribute to the actualisation of the wind map in Algeria. In this part, we have considered also the topographical aspect of Algeria. Such consideration is very helpful for understanding the wind potential reparation over the country. Finally, a techno-economical study of a stand along hybrid system (wind/diesel) in the site of Hassi-R’mel is considered. Via this study, it has been found that been found that the site of Hassi-R’mel is very adequate for wind energy conversion systems. [ABSTRACT FROM AUTHOR]