Feature fusion and similarity computation are two core problems in 3D object tracking, especially for object tracking using sparse and disordered point clouds. Feature fusion could make similarity computing more effic...
详细信息
In the scenarios of detecting the underwater low-speed small targets (e.g., frogmen or UUVs) in the very shallow water environment (e.g., harbor or shoal where the water depth is about several meters), much attention ...
详细信息
ISBN:
(纸本)9789811850707
In the scenarios of detecting the underwater low-speed small targets (e.g., frogmen or UUVs) in the very shallow water environment (e.g., harbor or shoal where the water depth is about several meters), much attention has been attracted on reverberation suppression. Based on the Doppler difference between the moving target echoes and the bottom reverberation dominant in the very shallow water, the traditional matched filtering may realize the separation of the bottom reverberation and the target echoes. However, the Doppler incurred by low-speed small targets is quite small, so the performance on the bottom reverberation suppression seriously degrades due to the limitation of Doppler resolution of the traditional approach. Therefore, it is urgent to improve its Doppler resolution to separate low-speed small targets out from the nearly static bottom reverberation. Generally, the reverberation and the target echoes can be considered as the weighted sum of the copies of transmitted signal with different delay and Doppler, which indicates that "the cross-ambiguity function of the received echo is approximately the two-dimensional convolution of the auto-ambiguity function of transmitted signal and the generalized "target" reflectivity density function (i.e., the weighted sum of the 2-D Dirac Delta function convolved with different delays and Doppler shifts)". In this paper, regarding the auto-ambiguity function of the transmitted signal as the 2-D point spread function (PSF), an iterative deconvolution algorithm called the Richardson-Lucy (R-L) algorithm is exploited to deblur the conventional delay-Doppler output. This processing can obtain approximately the generalized "target" reflectivity density function similar to the thumbtacks, which can significantly improve the resolution of the delay and Doppler of the raw output, and separate the slow-speed small targets submerged by the bottom reverberation. Simulations show the effectiveness and superiority of the proposed
Advances in computer science and technology, coupled with the growing societal demand for enhanced safety, have paved the way for innovative smart home environments. While current smart home systems can send alarms an...
详细信息
Steel fiber reinforced concrete(SFRC)has drawn extensive attention in recent years for its superior mechanical response to dynamic and impact *** on the existing test results,the highstrength steel fibers embedded in ...
详细信息
Steel fiber reinforced concrete(SFRC)has drawn extensive attention in recent years for its superior mechanical response to dynamic and impact *** on the existing test results,the highstrength steel fibers embedded in a concrete matrix usually play a strong bridging effect to enhance the bonding force between fiber and the matrix,and directly contribute to the improvement of the post-cracking behavior and residual strength of *** gain a better understanding of the action behavior of steel fibers in matrix and further capture the failure mechanism of SFRC under dynamic loads,the mesoscopic modeling approach that assumes SFRC to be composed of different mesoscale phases(i.e.,steel fibers,coarse aggregates,mortar matrix,and interfacial transition zone(ITZ))has been widely employed to simulate the dynamic responses of SFRC material and structural *** paper presents a comprehensive review of the state-of-the-art mesoscopic models and simulations for SFRC under dynamic *** approaches for the SFRC mesoscale model in the simulation works,including steel fiber,coarse aggregate,and the ITZ between them,are reviewed and compared *** material models for different phases and the interaction relationship between fiber and concrete matrix are summarized ***,some example applications for SFRC under dynamic loads(i.e.,compression,tension,and contact blast)simulated using the general mesoscale models are ***,some critical analysis on the current shortcomings of the mesoscale modeling of SFRC is highlighted,which is of great significance for the future investigation and development of SFRC.
We use Monte Carlo method to establish a randomly undulating homogeneous layered medium model. Then the co-offset GPR data for the built geological model is simulated by FDTD. The ray-tracing based inversion is applie...
详细信息
Radio imaging method (RIM) also called cross-hole electromagnetic wave method, is widely used in mineral exploration, engineering exploration and other fields. The RIM system can collect multi-frequency information, b...
详细信息
Borehole radar has been widely used in engineering, exploration and other fields, and the detection distance of borehole radar is an important indicator to measure its performance. The detection distance of borehole r...
详细信息
The detection capability of pulsed Coherent Doppler Wind Lidars (CDWLs) is limited by low Signal-to-Noise Ratios (SNRs). Therefore, it is critical to develop suitable signal processing algorithms. This paper proposes ...
详细信息
The detection capability of pulsed Coherent Doppler Wind Lidars (CDWLs) is limited by low Signal-to-Noise Ratios (SNRs). Therefore, it is critical to develop suitable signal processing algorithms. This paper proposes an enhanced method that integrates Variational Mode Decomposition with Particle Swarm Optimization (VMD-PSO) for wind detection, using the effective detection range as the fitness function. By incorporating wind velocity continuity across range gates, the fitness function enhances the robustness and accuracy of the optimization process, particularly under low-SNR conditions. Simulation results demonstrate that the proposed fitness function improves the ability of the optimized VMD-PSO algorithm to process noisy signals, enhances the stability of extracting effective signals, and ensures wind velocity accuracy. Furthermore, using a developed CDWL system, the algorithm increased the detection range by up to 120.5% under the same pulse accumulation conditions. At the same detection capability, it reduced the required number of pulse accumulations, enhancing the overall performance of the CDWL system.
Distributed Acoustic Sensing (DAS) is promising for traffic monitoring, but its extensive data and sensitivity to vibrations, causing noise, pose computational challenges. To address this, we propose a two-step deep-l...
详细信息
Feature extraction and classification are the main body of acoustic target recognition. Firstly, amplitude extraction based on harmonic set, MFCC and wavelet packet decomposition are selected as feature selection meth...
详细信息
暂无评论