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This paper outlines novel approaches to design a new generation of distributed networks of acoustic sensors. The key-concept is marked by the use of time-frequency signal analysis tools directly embedded at the sensor node. The general framework for analysis at the acoustic sensor level is based on spectrogram which is very simple and easy to implement. The choice of the detection threshold in time-frequency...
This paper presents several methods applied for the detection and localization of electrical arcs measured while survelling photovoltaic power systems. Firstly, we proposed the use of energy detectors for transients (spectrogram and wavelet) and compared them with statistical methods (Maximum Likelihood Estimation (MLE)), classical signal processing methods (Matched Filter, Zero Crossing), but not...
This paper presents two methods applied in the context of surveilling and localizing electrical arcs which usually occur in photovoltaic power systems. The wavelet analysis has proved to be very powerful in transient signal detection, namely in multiscale edge detection, thereby we use this method to detect the electrical arcs and to localize them in time. Secondly, we applied the recurrence plot...
This paper proposes a new method for detection of the vortex presence in fluid flow based on an active acoustic system. The experiment that validates the theory was done on a reduced scale facility using ultrasonic transceivers. The main objective was to highlight the effect of a cavitation vortex on an applied wide band signal. In order to accomplish that, the Recurrence Plot Analysis (RPA) was investigated...
This paper introduces a stochastic approach that considers the distributed classification problem for a network of underwater acoustic sensors. The proposed classifier applies the third order polynomial regression to the instantaneous frequency extracted from time-frequency representation of different classes of signals and represent the polynomial's coefficients in a three-dimensional representation...
This paper presents a synthesis approach based on a variable slope profile. The method is demonstrated by synthesizing an antenna with a quasi-constant gain over a given frequency range. The antenna configuration resulting from synthesis was simulated, manufactured and measured in order to validate our method.
We have previously proposed an indoor measuring technique for antenna gain, based on averaging a normalized transfer function over a distance range. Simulated and measured results have also been presented, in order to validate the method. In this paper, we assess the accuracy of our method by comparing the results to those issued from a traditional, non-anechoic approach, i.e., the time-gating method,...
Transient signals are very difficult to characterize due to their short duration and their wide frequency content. Various methods such as spectrogram and wavelet decomposition have already been extensively used in the literature to detect them, but show limits when it comes to near similar transients discrimination. In this paper, we propose the multi-lag phase space analysis as a way to characterize...
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