Distributed phased multiple-input multiple-output (PA-MIMO) radar systems on moving platforms combine the spatial diversity of MIMO radars with the coherent gain of phased-array radars, making them ideal for dynamic e...
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underwater autonomous capture operations offer significant potential for reducing labor and health risks in sea organism industries. This study presents a comprehensive solution for cross-domain underwater object dete...
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The underwater heat exhausting source can cause the thermal difference of the surrounding and surface *** this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simula...
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The underwater heat exhausting source can cause the thermal difference of the surrounding and surface *** this paper,the thermal character caused by the underwater heat exhausting source is studied by numerical simulation and *** results show that the thermal floating distance is related with the sailing velocity of the underwater *** higher the velocity is,the longer the hot wake is,and the broader the hot scope *** relative distance of the thermal floating spot is almost in a logarithmic law with the *** experimental results are accordant with the numerical simulation,and the obvious hot wake can be observed by the moving underwater heat exhausting source testing with temperature sensors and infrared camera.
In this paper, we address the challenge of data association in scenarios involving multiple observers for underwater non-cooperative localization, where it is unclear how measurement data from different stations corre...
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ISBN:
(数字)9798331531836
ISBN:
(纸本)9798331531843
In this paper, we address the challenge of data association in scenarios involving multiple observers for underwater non-cooperative localization, where it is unclear how measurement data from different stations corresponds to the same target. We propose a novel data association method that leverages the inverse cotangent of azimuthal sequence features. The method first calculates the sequence of cotangent values measured by each station's bearing in a limited time. Linearly analyzes the sequence to obtain the slope, and finally realizes the data association according to the characteristic that the inverse cotangent value of the slope corresponds to the target's motion heading. The simulation results show that the proposed method has better association localization ability compared with the traditional method, overcomes the problem of the conventional method that the computational volume is too large when the number of observation stations and targets is large, and ensures the association correctness under a certain error.
Reverberation is the major interference of active detection, discrimination between target echo and reverberation is difficult when the reverberation is very strong. For the distinguishing of underwater target echo wi...
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Reverberation is the major interference of active detection, discrimination between target echo and reverberation is difficult when the reverberation is very strong. For the distinguishing of underwater target echo with strong interference, the modulation feature of echo and reverberation spectrum are characterized by signal spectral flatness measure, and the relationship between signal spectral flatness and target physical properties are theoretically formed. A method of discrimination between broadband underwater target echo and reverberation that based on signal spectral flatness characteristics difference is proposed and studied. Sea experiment results of complex underwater target broadband acoustic scattering have shown that signal spectral flatness characteristics of underwater target broadband echo and reverberation have obvious differences. Target echo and reverberation can be well distinguished using the proposed method.
In most priority scheduling algorithms, the num- ber of priority levels is assumed to be unlimited. However, if a task set requires more priority levels than the system can support, several jobs must in practice be as...
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In most priority scheduling algorithms, the num- ber of priority levels is assumed to be unlimited. However, if a task set requires more priority levels than the system can support, several jobs must in practice be assigned the same priority level. To solve this problem, a novel group priority earliest deadline first （GPEDF） scheduling algorithm is pre- sented. In this algorithm, a schedulability test is given to form a job group, in which the jobs can arbitrarily change their or- der without reducing the schedulability. We consider jobs in the group having the same priority level and use shortest job first （SJF） to schedule the jobs in the group to improve the performance of the system. Compared with earliest deadline first （EDF）, best effort （BE）, and group-EDF （gEDF）, simu- lation results show that the new algorithm exhibits the least switching, the shortest average response time, and the fewest required priority levels. It also has a higher success ratio than both EDF and gEDF.
We present preliminary results on the VLSI design and implementation of a novel and promising algorithm for accurate high-speed Fourier analysis and synthesis. The Arithmetic Fourier Transform (AFT) is based on the nu...
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The recognition rate of the auditory periphery features decreases when the model is used to identify underwater targets in practice. To solve this problem, an improved method based on Gammatone filter bank is proposed...
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The recognition rate of the auditory periphery features decreases when the model is used to identify underwater targets in practice. To solve this problem, an improved method based on Gammatone filter bank is proposed. Firstly, after the reason of the decreasing of the recognition results is analyzed, the mechanism of multichannel data acquisition in acoustic engineering may narrow down signal frequency range, which leads to time-frequency features distortion. Secondly, the Gammatone filter bank is implemented to simulate frequency decom- position characteristics of human ear basilar membrane. Since the class information of the underwater noise signal is mostly contained in low frequency range, the auditory features of the conventional model are interpolated and the channel number of the filter bank and the central frequency of each frequency band are adjusted accordingly to obtain a 27-dimensional feature vector of the narrow-band target signal. The adjusted model may reflect the target＇s time- frequency feature more precisely. Finally, the performance of the auditory features is tested by a Neural Network classifier. The experiment results show that the modified auditory model is more effective than the conventional ones. The major information contained in broadband signals is reserved and the classification ability for real targets is further enhanced. The recog- nition results are increased from 82.59% to 88.80%. The modified auditory features effectively improve the recognition rate for underwater target radiated noise signals.
To resolve the problem that reverberation signal usually seriously affect active sonar's detection performance, Blind Source Separation method of the Fractional Fourier Domain is adopted in this study. First, the ...
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This paper presents a comprehensive methodology for modeling ship target radiated noise spectrum characteristics, addressing the challenges of limited data availability. The proposed methodology includes data collecti...
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