Acoustic Detection Technology Research Articles

Testing the Spatial Accuracy of Address-Based Geocoding for Gunshot Locations

We assess the positional accuracy of address-based geocoding of shooting incidents relative to the location recorded via acoustic gunshot detection technology. This provides a test of the accuracy of typical address-based geocoding methods used in crime analysis, as well as evidence for how much accuracy one gains when using sensors. Examining more than 1,000 shooting incidents in Wilmington, North Carolina, we find that the majority of address-based incidents are quite accurate, on average within 60 feet of the actual location (using a street centerline geocoder) or within 90 feet (using Google rooftop geocoding). Based on the incident narrative, however, we identify a subset of transcription errors in over 10 percent of the cases that increases the distance between the true shooting location and that geocoded using address data. This suggests that mechanisms to prevent human errors might be more frugal than those relying on sensors in geocoding shooting incidents.

Rancang Bangun Transmitter dan Receiver untuk Sistem Komunikasi Akustik Bawah Air

Since 2016 acoustic detection technology for marine resources had been developed which was relatively simple and sophisticated, namely Ocean Acoustic Waveguide Remote Sensing. The technology was useful for monitoring and quantifying underwater targets such as marine resources and the environment that can be conducted continuously, sustainable, in situ, real-time, and low cost. This research had designed an Ocean Acoustic Remote Sensing technology instrument to detect signal propagation range. The step taken in this research was to build an acoustic device system such as transmitter and receiver based on TR-103 transmitting transducer sensor and Benthos Aq-1 receiving transducer. Based on the experiment results, the transmitter and receiver designed were confrmed with the measured piezoelectric quantity specifcations. The results at open ocean in the Thousand Islands showed the detection range of transmitter signal propagation to the receiver was 100 m.

Simulation research of underwater passive direction finding technology

As one of the indispensable technologies for underwater target detecting, underwater acoustic passive detection technology has always been a hot spot in marine system research. A vector sensor can detect underwater targets by combination with the pressure and vibration velocity information; vector sensor array can obtain higher gain than pressure array with the same number hydrophones. Vector sensor can reduce the length of the underwater sensor array and can detect underwater targets in the case of low signal to noise ratio. This is the goal that many researchers strive to solve for many years; therefore, vector sensor passive detection technology has far-reaching scientific research value.Through the verification of the simulation experiment, the azimuth estimation technique and the adaptive frequency estimation technique are feasible. By estimating the azimuth sequence and frequency sequence of the target radiation signal, the relevant information of the target can be obtained, and so it is of great significance in the research of underwater acoustic detection technology.

The research of passive detection parameter measurement based on vector sensor

As one of the indispensable technologies for underwater target detecting, underwater acoustic passive detection technology has always been a hot spot in marine system research. A vector sensor can detect underwater targets by combination with the pressure and vibration velocity information; vector sensor array can obtain higher gain than pressure array with the same number hydrophones. Vector sensor can reduce the length of the underwater sensor array and can detect underwater targets in the case of low signal to noise ratio. This is the goal that many researchers strive to solve for many years; therefore, vector sensor passive detection technology has far-reaching scientific research value. Through the verification of the simulation experiment, the azimuth estimation technique and the adaptive frequency estimation technique are feasible. By estimating the azimuth sequence and frequency sequence of the target radiation signal, the relevant information of the target can be obtained, so it is of great significance in the research of underwater acoustic detection technology.

An Effective Method for Submarine Buried Pipeline Detection via Multi-Sensor Data Fusion

Submarine pipelines are important resource delivery devices between land and ocean. For safety reasons, pipelines are often embedded beneath the seabed at a certain depth, to reduce the risk of direct damage to the pipeline. In the past, various kinds of detection equipment have been used for pipeline inspection, to ensure the normal operation of pipelines in practical applications. Acoustic detection technology is the dominant method to monitor buried submarine pipelines. Extracting and integrating the information in acoustic images, such as the route and burial depth, can help to monitor the status of a pipeline. However, most of the existing methods are based on limited parameters, and they cannot be used to precisely detect and locate a submarine pipeline under complex conditions. In this study, a multi-sensor surveying system was used, which integrates a sub-bottom profiler (SBP) and the Shipborne Over- and Under-Water Integrated Mobile Mapping System (SiOUMMS) on the same ship. The data acquired in this system include acoustic profile images and the over- and under-water topography of the pipeline route area. We also designed a position deviation correction method to improve the accuracy of the pipeline detection positioning, i.e., pipeline positioning correction in the real-time kinematic (RTK) positioning data and pipeline horizontal route correction in the integrated data. Compared with the uncorrected pipeline detection positioning result, the reliability of the pipeline inspection result is greatly improved, and the effectiveness and merit of the proposed method are clearly demonstrated. Finally, we conducted a buried pipeline safety assessment for the installation of newly designed wharf piles at Mawan Port of Shenzhen, China, where the results showed that one of the first rows of wharf piles would collide with the sewage pipeline.

Application of EMD Technology in Leakage Acoustic Characteristic Extraction of Gas-Liquid, Two-Phase Flow Pipelines

Nowadays, the exploitation and transportation of marine oil and gas are mainly achieved using multiphase flow pipelines. Leakage detection of multiphase flow pipelines has always been the most difficult problem regarding the pipeline safety. Compared to other methods, acoustic detection technology has many advantages and high adaptability. However, multiphase flow pipelines are associated with many noise sources that affect the extraction and recognition of leakage signals. In this study, the mechanism of leakage acoustic source generation in gas-liquid, two-phase pipelines is analyzed. First, an acoustic leakage detection experiment in the multiphase pipelines is conducted. The acoustic signals are divided into two classes in accordance with whether leakage occurs or not. The original signals are processed and analyzed based on empirical mode decomposition (EMD) processing technology. Based on the use of signal processing, this study shows that EMD technology can accurately identify the leakage signal in the gas-liquid, two-phase pipeline. Upon increases in the leakage aperture sizes, the entropy of the EMD information of the acoustic signals gradually increases. Finally, the method of the normalized energies characteristic value of each IMF component is also applied in leakage signal processing. When the liquid flow is maintained constant, the energy values of the IMF components change in a nonlinear manner when the gas flow rate increases. This verifies the feasibility of use of the acoustic wave sensing technology for leak detection in multiphase flow pipelines, which has important theoretical significance for promoting the development of safe and efficient operation in two-phase flow pipelines.

Passive detection parameter measurement of azimuth and frequency based on single vector sensor

This paper mainly studies the measurement technology of passive detection parameters based on single vector sensor. Ship radiated noise contains a lot of target information, so the extraction of the line noise of the ship's radiated noise is of great significance in the measurement of passive detection parameters. The radiation noise of the ship is a broadband spectrum modulated by the spectral signal envelope. In this paper, the mathematical model of the radiation noise of the ship is simulated and the demodulation of the ship's radiated noise is carried out by using the square demodulation and the absolute value demodulation. The average azimuth and complex intensifier are used to estimate and analyze the target azimuth, and the estimated angle is statistically processed by histogram and weighted histogram. For the frequency estimation technique, the adaptive frequency estimator based on the adaptive notch filter and the adaptive LMS (least mean square) algorithm is chosen to study the target signal frequency.Through the verification of the simulation experiment, the azimuth estimation technique and the adaptive frequency estimation technique are feasible. By estimating the azimuth sequence and frequency sequence of the target radiation signal, the relevant information of the target can be obtained, so it is of great significance in the research of underwater acoustic detection technology.

Research on passive detection parameter measurement technology based on single vector sensor

Passive detection as a major function of the sonar system, over the years has been the work of waterborne workers to solve the problem. This paper mainly talks about the measurement technology of passive detection parameters based on single vector sensor. The problem of low frequency line spectrum signal extracted from ship radiated noise is studied, and the azimuth sequence and frequency sequence are obtained by estimating and analyzing the low frequency line spectrum signal. Ship radiated noise contains a lot of target information, so the extraction of the line noise of the ship's radiated noise is of great significance in the measurement of passive detection parameters. The radiation noise of the ship is a broadband spectrum modulated by the spectral signal envelope. The average azimuth and complex intensifier are used to estimate and analyze the target azimuth, and the estimated angle is statistically processed by histogram and weighted histogram. For the frequency estimation technique, the adaptive frequency estimator based on the adaptive notch filter and the adaptive LMS (Least Mean Square) algorithm is chosen to study the target signal frequency. Through the simulation experiment, the azimuth estimation technique and the adaptive frequency estimation technique are feasible. By estimating the azimuth sequence and frequency sequence of the target radiation signal, the relevant information of the target can be obtained, so it is of great significance in the research of underwater acoustic detection technology.

Advances in leak detection and location based on acoustic wave for gas pipelines

With the rapid development of pipeline industry, the leakages of gas pipelines cause great energy waste and environmental pollution, especially security problems. Therefore, it is significant to study leak detection and location methods. At present, many leak detection methods have been developed for gas pipeline leakages, such as methods based on mass/volume balance, negative pressure wave, transient model, distributed optical fiber and acoustic waves, etc. Among them the traditional negative pressure wave method detects leakages based on the change of the absolute pressure in pipeline monitored by the pressure transmitter, while the acoustic method is based on the dynamic pressure monitored by the acoustic sensors. All evaluation indexes are considered as equivalent references, and after comparative analysis it can be known that acoustic method is promising and actual. And nowadays in this field, acoustic method is one of the hot issues. The acoustic method can perform full-scale display of pressure fluctuations caused by the leakages. The fundamental principle of the acoustic leak detection technology for natural gas pipelines is that an acoustic pressure perturbation is generated when leakage occurs. It transmits through gas to both ends of the pipeline and is acquired by the dynamic pressure sensors installed to the pipeline, which will be signal-processed by computer to determine whether leakage occurs or not. The amplitude of dynamic pressure wave is large and it contains a wide frequency range. The leak location technology based on dynamic pressure waves is one of the most potential methods in the future. The generation and attenuation of the dynamic pressure waves are the key points which determine the detection accuracy and the location precision. The leak-acoustics generation mechanism influences the leak-acoustics characteristics and signal recognition. The main reason of leak-acoustics generation for natural gas pipelines is the sonic source fluctuations. The propagation characteristics of leakage acoustic waves in gas pipelines are necessary to study.The accuracy of the velocity and the time difference restricts the application of the acoustic leak detection and location method. Then the location method is proposed which is based on the propagation model and takes no account of the velocity and the time difference. This dissertation consists of the following three parts which contribute to make the research status and future development clear: the fundamentals of the acoustic method, the related researches of recent five years (domestic and overseas) and the outlook of the leak monitoring based on acoustic wave method of gas pipelines, especially the analyses about the researches on acoustic leak detection and location method. The conclusions can be concluded that acoustic leak detection method is an important way to protect pipelines from failure and to decrease the risks which can be executed timely and accurately.

A Review of Research on Acoustic Detection of Heat Exchanger Tube

Leakage in heat exchanger tubes can result in unreliable products and dangerous situations, which could cause great economic losses. Along with fast development of modern acoustic detection technology, using acoustic signals to detect leakage in heat exchange tube has been gradually accepted and considered with great potential by both industrial and research societies. In order to further advance the development of acoustic signal detection technology and investigate better methods for leakage detection in heat exchange tube, in this paper, firstly, we conduct a short overview of the theory of acoustic signal detection on heat exchanger tube, which had already been continuously developed for a few decades by researchers worldwide. Thereafter, we further expound the advantages and limitations of acoustic signal detection technology on heat exchanger tube in four aspects: 1) principles of acoustic signal detection, 2) characteristics of sound wave propagation in heat exchanger tube, 3) methods of leakage detection, and 4) leakage localization in heat exchanger tube.

Application Research of 3D Imaging Sonar System in Salvage Process

In the salvage process, data about the shape of shipwreck, sink sitting posture, buried degree and other related information should be required in order to develop salvage program. Three-dimensional imaging sonar is used to provide such data for salvage work by underwater acoustic detection and three-dimensional imaging technology. An application example is described and the results show the effectiveness.

基于频率调制连续波的干涉型光纤声传感器信号检测技术

基于频率调制连续波的干涉型光纤声传感器信号检测技术

基于光纤光栅法布里珀罗干涉仪的液体介质声波检测技术研究

基于光纤光栅法布里珀罗干涉仪的液体介质声波检测技术研究

Gas pipeline leakage detection based on acoustic technology

The acoustic signal of gas pipeline leakage has advantage in short delay time and carries physical information of the leakage, so it can be used for the diagnosis and localization of the pipeline leakage. In the long distance pipeline, collecting vibration signal caused by sound field has important significance to research of acoustic leakage detection technology. In order to get sound signal, first, this paper researches on the phonation principle of the pipeline leakage and the characteristic of the sound source, and the sound field is established on the basis of aero acoustics. Second, the vibration of the pipeline wall is analyzed with the harmonic analysis technology of the ANSYS software when the leak wall bears broadband harmonic sound pressure. Finally, the field experiment demonstrates that this approach can improve detection ability of small leakage with low false alarm rate.

Acoustic detection technology for gas pipeline leakage

Gas leakage from pipeline leads to significant environmental damages and industrial hazards, so small leakage detection for gas pipeline is essential to avoid these serious leakages. However, because of the high frequency component of leakage signal attenuates quickly, traditional detection method which inspects pressure or vibration signal has problem to get effective information from leakage signal. So, a novel detection method based on acoustic wave is proposed. This paper, firstly, researches on the phonation principle of pipeline leakage and the characteristic of sound source, and simulates the leakage acoustic field on the basis of aero acoustics. Secondly, using Wavelet Packet Transform method and Fuzzy Support Vector Machine pattern classification, the laboratory testing for identifying acoustic signal of gas pipeline leakage is presented. Finally, the field application demonstrates that the detection system could identify small gas leakage effectively and avoids false-alarms which caused by running conditions with a good prospect.

Analysis of Directional Accuracy of Three Single Arrays

Acoustic sensoxr array technology is the one of the key technology of passive acoustic detection technology, whether the single array has a good performance on direction will directly affect the accuracy of the locating system. In order to choose the best single array on direction, in this paper, respectively selected representative plane array and spatial array from a number of typical single arrays to analyze, find out the advantages and disadvantages of two single arrays. On this basis, around the idea of integrating the advantage of symmetric spatial array and plane cross five-element array, according to characteristics of the structure of this two kinds of arrays to design a new locating model—spatial five-element array. And compared with two kinds of single array mentioned above, the results of comparison show that the locating accuracy of spatial five-elements array is superior to both kinds of mentioned, and have high engineering value.

Acoustic particle detection – From early ideas to future benefits

The history of acoustic neutrino detection technology is shortly reviewed from the first ideas 50 years ago to the detailed R&D programs of the last decade. The physics potential of ultra-high energy neutrino interaction studies is discussed for some examples. Ideas about the necessary detector size and suitable design are presented.

Acoustic Leak Detection Technology for Water/Steam Small Leaks and Microleaks into Sodium to Protect an SFR Steam Generator

This technical note presents the results of an experimental study of the role of water in sodium leak noise spectrum formation and at various water/steam leak rates of <1.0 g/s. The conditions and ranges for the existence of bubbling and jetting modes in water/steam outflow into circulating sodium through an injector device were determined to simulate a defect in the wall of the heat-transmitting tube of a sodium-water steam generator (SG). Based on experimental leak noise data, the simple dependency of the acoustic signal level on the leak rate of a microleak and small leaks at different frequency bands was presented for the principal analysis to develop an acoustic leak detection methodology for a KALIMER-600, 600-MW(thermal) reactor (K-600) SG, with the operational experiences for noise analysis and measurements of the Bystry neutron (fast neutron) reactor BN-600. Finally, the methodology was tested with the Korea Atomic Energy Research Institute (KAERI) acoustic leak detection system using sodium-water reaction signals of the Institute of Physics and Power Engineering and background noise of the Prototype Fast Reactor (PFR) superheater for methodology development of KAERI, and it was able to detect a leak rate of under 1 g/s and a signal-to-background noise ratio of −22 dB, using this system and methodology.

Profiling of molecular interactions in real time using acoustic detection

Acoustic sensors that exploit resonating quartz crystals to directly detect the binding of an analyte to a receptor are finding increasing utility in the quantification of clinically relevant analytes. We have developed a novel acoustic detection technology, which we term resonant acoustic profiling (RAP™). This technology builds on the fundamental basics of the “quartz crystal microbalance” or “QCM” with several key additional features including two- or four-channel automated sample delivery, in-line referencing and microfluidic sensor ‘cassettes’ that are pre-coated with easy-to-use surface chemistries. Example applications are described for the quantification of myoglobin concentration and its interaction kinetics, and for the ranking of enzyme-cofactor specificities.

Akubio: label-free screening of molecular interactions using acoustic detection

Akubio was formed in August 2001 to exploit highly sensitive acoustic detection technology discovered by scientists at the University of Cambridge, UK. The technology enables rapid, label-free determination of molecular interactions. Receptor–ligand interactions can be probed either in buffered solutions or in complex biological fluids, as the detection process is not adversely affected by non-specific binding of sample contaminants. Applications are being developed for the diagnosis of clinical infections, the screening of libraries for receptor binding, and the determination of molecular interaction affinities in general.