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The noise spatial correlation coefficient between two array elements deployed vertically in real deep ocean environment is not consistent with that in isotropic ambient noise field because of surface-distributed wind driven noise sources. Therefore, it is necessary to analyze the performance of vertical line array spatial gain properly. A method for modeling wind-driven ambient noise field is described...
In this paper, we present a novel codebook-driven speech enhancement method, which applies speech harmonic structure. Our algorithm is able to remove more residual noise in harmonic bands because we combine speech harmonic structure and codebook. Firstly, we utilize the speech harmonic structure to estimate prior speech presence probability. Then we use it to appraise the noise autoregressive (AR)...
Based on equivalent scatter center model of coning target, the micro-Doppler (m-D) signals induced by precession mainly consist of two components, i.e., cone node scatter signal varies in a sine and bottom scatter signal varies in a complex form time-frequency (TF) plane. As these two components are overlapped in the TF plane, this makes it hard to estimate the parameters of the target. Aiming at...
In beamforming, maximum likelihood estimation is used to estimate the covariance matrix by using the received data. In order to improve the estimation accuracy of covariance matrix and reduce noise, based on array domain, an preceding method for broadband beamforming using subband smooth is proposed which smoothes of each subband before the covariance matrix of the received data is estimated. The...
The DOA estimation problem for wideband signals has attracted much attention in the past years, and how to utilize and derive the common DOA information among frequency bins is the essential question. We address the wideband DOA estimation problem in this paper, and to solve this problem we propose a joint sparse Bayesian learning algorithm based on the sparse signal representation (SSR) of the covariance...
A detection method of short-time double-Duffing chaotic oscillator array with variable amplitude coefficients (VASTD-Duffing) is proposed for the problem of Duffing chaotic oscillator system's miss detection generated by envelope fluctuation and distribution information in the time domain of the signals. A short-time characteristic window approach and periodic extension method to envelope fluctuation...
To protect the structural feature and polarimetrie property in the speckle reduction of polarimetrie synthetic aperture radar (PolSAR) images, an improved speckle filter is developed based on a novel structural judgment and an improved four-components polarimetric decomposition (IFCPD) proposed from the Pauli decomposition and the Yamaguchi decomposition. The novel structural judgment based on the...
How a grain ahead affecting a dolphin's transmitting performance is examined. A finite element approach was applied to numerically simulate the acoustic field around a dolphin with a small grain ahead of it. Acoustic intensity distribution, beam pattern, angle of strong beam and 3dB beam width are compared to investigate the differences caused by the small grain ahead of the dolphin. Although the...
Coordinated multi-points (CoMP) transmission has been widely proved to be effective to combat inter-cell interference in 3GPP LTE-Advanced systems. However, implementation complexity of inter-site CoMP and relatively low capacity gain of intra-site CoMP motivate us propose a beam coordinated multipoints (Beam-CoMP) transmission scheme for 5G millimeter-wave cellular network. Considering the specific...
Due to waveguide dispersion and array shape distortion, target's energy spreads in the vicinity of direction of arrival in spatial orientation spectrum. To solve this problem, a spatial spectrum estimation method using beam signal spectral decomposition is proposed. Utilizing correlation between signals which spread in multiple beams, beam signal spectrum is decomposed using singular value decomposition...
In this paper, the second-order stochastic resonance (SR) system with Levy noise is analyzed, and the improved numerical method is proposed to obtain the output signal sequence after the SR system. Then the matched stochastic resonance (MSR) system is investigated and derived to produce a stable SR phenomenon in Levy noise circumstance. The matched performance is then evaluated which reflected the...
This paper introduces the basic theory and method of compressed sensing, and its application in DOA estimation. The theory uses a new sampling method through sparse sampling and reconstruction of the signal to break through the limitation of the Nyquist sampling theorem, effectively solving the inherent shortcomings of classic spatial spectrum estimation algorithms.
The speed of the target can be estimated by the sound pressure cross-correlation of the line spectrum of the moving target at different time intervals. However, a slight deviation of the line spectrum has a significant influence on the estimated result. In this paper this phenomenon is analyzed from the theory, then the speed of the target is estimated when the line spectrum is biased. Experimental...
The deep learning is a popular research direction in machine learning field now. In this paper, the deep learning algorithms are used to recognize the underwater target radiated noises. The deep belief network (DBN) model and the stacked denoising autoencoder (SDAE) model are built respectively. Then the underwater acoustic simulated data of different types of targets as well as different states of...
Weak target detection is one of the key problems facing the foreign object debris (FOD) surveillance radar at the airport runway. A novel FOD detection algorithm based on higher order statistics features and support vector domain description (SVDD) classifier for 77GHz millimeter wave (mm-wave) radar is proposed in this paper. Clutter map constant false alarm rate (CFAR) is firstly applied to the...
Based on the characteristics of short pulse signals in the marine animals sound and the characteristics of the high temporal resolution of the wavelet transform, this paper proposed a new strategy of Constant False Alarm Rate(CFAR) pulse detection based on continuous wavelet transform(CWT). The CFAR pulse detection was carried out on each scale of the results of time frequency analysis of CWT. Then...
A novel blind time-frequency joint synchronization based on the cyclostationary of orthogonal frequency division multiplexing with offset quadrature amplitude modulation (OFDM/OQAM) systems is conceived in multipath channels conditions. The cyclic cumulants of OFDM/OQAM signals are derived firstly, symbol timing offset (STO) and carrier frequency offset (CFO) are estimated by employing two groups...
Convolutional neural network (CNN) extracts features from big data by using the multilayer network structure. Due to the high effectiveness, CNN has achieved great successes in many fields such as computer vision and speech analysis. However, CNN training is quite challenging because computing the gradients through multiple layers is time consuming. In this paper, we propose to accelerate the computation...
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