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There is a tiny difference between the main peak and side peaks after the traditional quadratic correlation calculation in the time-delay estimation of passive acoustic positioning system. It is easy to lead to a wrong peak value when the system resolution is low or mutations caused by noises occur near the side peaks. In order to weaken the influence of the quadratic correlation side peaks, the method...
Electromagnetic attacks are non-invasive attacks and pose serious threats to the security of cryptographic devices. However, its environment is complex and the noise on electromagnetic traces is often large. Thus, traditional differential electromagnetic analysis (DEMA) and correlation electromagnetic analysis (CEMA) require a lot of electromagnetic traces to recover the key used in the cryptographic...
Efficient denoising of hyperspectral imagery (HSI) relies on an representational model that is capable of capturing the spatial and spectral correlation in HSI. Recently, an intrinsic representation (IR) approach based on the linear spectral mixture model (LSMM) was proposed for unsupervised feature extraction. The IR model constitutes a sound representational model due to its ability to account for...
Some spectrum indicators, such as central length, SNR, spectral resolution affect accuracy of water quality retrieval, but are ignored due to the limitations of a single sensor. Take Chlorophyll a retrieval as an example, the sensitivity analysis was conducted using single band, first-order differential and band ratio methods. The results indicated that optimal central wavelength would change because...
Aiming at pseudo random sequence, a precise synchronization method tolerating large capture error is proposed in this paper. It firstly formulates the correlation function of the pseudo random sequence in the range of one chip period around the capture position as two straight lines and parameters of which are acquired by employing least squares (LS) algorithm. Then, intersection point of the two...
Sparse unmixing is based on the assumption that each mixed pixel in the hyperspectral image can be expressed in the form of linear combination of a number of pure spectral signatures that are known in advance. Despite the success of sparse unmixing based on the L0 or L1 regularizer, the limitation of these approach focuses on analyzing the hyperspectral data without incorporating spatial structure...
In case of wideband communications the analog-to-digital converter becomes a power consumption implementation bottleneck. Alternatively, transmission schemes based on coarse (1-bit) quantization and oversampling at the receiver can be beneficial. In this regard, information is conveyed in the zero-crossings. However, in presence of spectral constraints the waveform design becomes a challenge. In this...
In this work, we study the application of analog Joint Source Channel Coding (JSCC) techniques for the transmission of correlated information over fading Multiple Access Channels (MACs) using multiple receive antennas. We consider the distributed encoding of the user information with two different analog JSCC schemes: module-like mappings and uncoded transmission. We evaluate the performance of these...
The potential gains of multiple antennas in wireless systems can be limited by channel state information imperfections. In this context, this paper tackles the limited feedback in multiuser correlated multiple input single output (MU-MISO). We propose a framework to feedback the minimum number of bits with limited performance degradation. This framework is based on decor relating the channel state...
Weighted MUSIC algorithm based on delay correlation is proposed because of the problem that MUSIC algorithm has low DOA estimation performance in actual system. The proposed algorithm makes full use of delay correlation information of impinging signals to improve estimation performance. We obtain a new receiving data matrix which has the same array manifold with original data by observing association...
Signal correlation is mainly measured from similarity or dissimilarity between a tissue of interest and a tissue of reference. In this paper, similarity coefficient mapping (SCM) was modified to estimate signal correlation from both aspects and generates two maps. One map (RMM) depicts relative signal magnitude and the other (RM) reveals tissue difference. The modified method was validated with a...
Cognitive radio is an innovative technology which seeks to provide a new way to extend utilization of available spectrum. The spectrum detection is an essential problem for cognitive radio. Spectrum sensing is an efficient way to detect spectrum holes in cognitive radio network. In this paper, we present cyclostationary Detection Based on Non-cooperative spectrum sensing in cognitive radio network...
In this paper, the correlated double-Rayleigh distribution is introduced and analyzed. This distribution has been found to provide an accurate statistical description of the vehicle-to- vehicle multipath propagation. Novel infinite series expressions for the joint probability density and the cumulative distribution functions are derived, while the joint moments are also obtained in closed form. Although...
The theoretical output signal-to-noise ratio (SNR) values computed for cross-correlation, least-squares (LS) and various versions of the least mean square (LMS) algorithm have been found to agree with the respective output SNRs exhibited by range profile estimates generated by these algorithms in Matlab when the transmitted noise waveform's spectrum is flat. In this paper, the degree of agreement...
This paper proposes a blind phase coded signal interception method for a potential target to recognize whether it is being looked at. The interception method is based on identifying the carrier frequency (fc) of the received signal with unknown phase coding from the ratio of the second derivative of the signal with itself. It is shown that this ratio is equal to −(2πfc)2. The second derivative is...
In this paper, a two-stage phase-increment-based frequency estimator with a general pilot-symbol-assisted- modulation (PSAM) structure is proposed for burst-mode communications. We derive the true Cramer-Rao bounds (CRBs) under the general PSAM structure for pure data-aided (DA) estimator. The proposed phase increment-based estimator is a pure DA estimator and implemented via two stages. In the first...
Functional Magnetic Resonance Imaging (fMRI) methods produce high dimensional representation of cognitive processes under heavy noise due to the limitations of hardware and measurement techniques. In order to reduce the noise and extract useful information from the fMRI data, a sequence of pre-processing techniques, such as smoothing with spatial filters and z-scoring, are used. In this study, we...
This paper investigates the outage performance of the secure cooperative system over correlated Rayleigh fading channels in the presence of the eavesdropper and the jammer. Assuming that the transmitter knows the full channel state information (CSI) before transmission, there exist one eavesdropper and multiple cooperative relay nodes in system, and a relay node is chosen to act as jammer to send...
In this paper, a discussion is made on the optimization methods that can solve the low autocorrelation sidelobes problem for polyphase sequences. This paper starts with a description and a comparison of two algorithms that are commonly used in the literature: a stochastic method and a deterministic one (a gradient descent). Then, an alternative method based on the Random Walk Metropolis-Hastings algorithm...
The paper introduces an OFDM signal detector based on cyclic correlation function. The detector belongs to the class of blind SCD detectors. The paper presents the main relations connected with the idea of cyclostationarity and cyclostationary features of OFDM signals. Results of simulations are presented as well.
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