The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, we present a novel approach for the sensing of erosive cavitation phenomena in underwater facilities. Cavitation phenomena are known for their destructive capacity of underwater structures and are caused by the pressure decreasing followed by an implosion when the cavitation bubbles find an adverse pressure gradient. Conventional cavitation detection techniques are based on passive...
The underwater object imaging is an important task for the surveillance and monitoring of underwater environment in a non-intrusive manner. The acoustic methods have been proved to be very powerful for the detection and localization of underwater objects. This paper proposes a new method for object imaging based on an acoustic system that uses multiple elements. The image is obtained using two main...
In this paper, we present a new approach of time of flight (TOF) estimation using wide band signals, based on compressive sensing (CS) reconstruction in warped domain. In real conditions, constraints related to signal's transmitting/receiving (such as the transducers configuration or the experimental setup) can affect the informational content of the signal. Thus, the received signals need content...
The paper presents a different approach based on an active acoustic system for the characterization of a vortex generating cavitation phenomenon. In the present work, the experiment was carried out in a reduced scale facility. The flow rate of the hydraulic system was varied and, when the flow became stable, the acoustic active system was started. The system is based on two ultrasonic transceivers...
This paper presents a new technique for acoustic transducers position offset compensation, based on compressive sensing reconstruction in the warped domain. In underwater acoustics, the transducers relative position is important for applications involving direction of arrival estimation, localization or source detection. When the transmitter-receiver transducers configuration is inappropriate, the...
Detection of objects in underwater environment is an important operation that can be aimed to assess the pollution in the region under study as well as to prevent intrusion of undesired objects in off shore power production facilities or in the restricted entrance area. The use of acoustic methods has been proven to be very powerful for the detection and localization of the underwater objects. This...
The distributed array of sensors is an interesting concept in the context of underwater environment monitoring. The signal processing distributed at sensors level has to have a low consumption (much less than the data transmission) and, in the same time, the processing efficiency needs to be satisfactory compared with a processing without any algorithmic complexity constraint. In this paper, we define...
In this paper we present a Software-Defined Radio approach for an Electric Arc locator system. The core of the proposed hardware implementation is the USRP (Universal Software Radio Peripheral) development platform. The novelty of this work lies in the application of telecommunication specific advanced signal processing methods in the field of energy generation and transmission. The main advantage...
Transient signals have proved to be difficult to characterize/classify because of their short duration and broad spectrum. Methods based on time-frequency analysis are used for transient detection, but their characterization is limited when it comes to similar signals that have close amplitudes and frequencies. This paper presents the multi-lag phase space analysis, an alternative to the classical...
The paper presents an acoustic signal processing approach for the surveillance of a water pipe and the characterization of the water hammer effect. The experiment is based on ultrasonic transceivers and the validation is made with pressure sensors. The major objective is to quantify the pressure variation into the pipe using a non-intrusive method. Therefore, the speed of the transient was determined...
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 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...
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,...
In this paper, we introduce a general framework for waveform design and signal processing, dedicated to the study of turbulent flow phenomena. In a bi-static configuration, by transmitting a specific waveform with a predefined instantaneous frequency law (IFL), within the bounds of the Kolmogorov spectrum, the turbulent media will modify the IFL at the receiving side. We propose a new methodology...
In this paper, we present a new technique for detecting and localising defects in metallic structures, using ultrasound non-destructive inspection. This technique consists in applying a dual path inspection and the matched filter to a stepped frequency-type signal. This new technique is compared with classical non-destructive testing approaches. An experimental setup is presented that allows us to...
In this paper, we present two techniques for the localization of electric arcs produced in photovoltaic power systems. High order statistic analysis (HOSA) and recurrence plot analysis (RPA) have already proven successful in detecting the partial discharges associated with the production of an electric arc in a high voltage power system. However, this solves only the first half of the problem, since...
In this paper, we propose a method for underwater inhomogeneities characterization using sparse representation of channel's impulse response. We consider the case of moving vortices created naturally or artificially that do not conserve their physical properties when observed at two distinct positions in space. Existing amplitude-based techniques fail to provide an accurate representation when the...
This paper deals with the challenges of water flow measurement in hydroelectric plants using acoustic scintillation. One of the drawbacks of ultrasonic signal propagation through water is that measurements require relatively clean water conditions. In water with significant amount of impurities, the level of transmitted signals may not be sufficient for an accurate flow measurement. In terms of signal...
The detection and characterization of burst signals are challenging tasks for time-frequency analysis, due to their very short duration. This paper investigates in this context the recurrence plot analysis (RPA) method, from which it derives the vector samples processing (VeSP) concept. The paper shows that VeSP is a generic framework that unifies signal processing concepts like histogram and autocorrelation,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.