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In recent years many chaos-based image cryptosystems are proposed. As encryption process is applied to the whole image, it is difficult to improve the efficiency. In this paper, wavelet decomposition is used in our algorithm to concentrate the main information of image to the low frequency part. Then high-strength chaotic encryption is applied. After that, wavelet reconstruction and Arnold scrambling...
Due to the self rotation and revolution of the earth and the satellite moving comparatively, the delay rate changes intricately and that affects correlation result when we use VLBI to detect Satellite. To solve the problem, a new method of delay-delay rate 2-D correlation is proposed which based on time-frequency 2-D correlation. This method applies ambiguity function calculation of time-frequency...
This paper proposes a novel algorithm of synthesizing 1/f-type fractal signal based on ISWT (inverse stationary wavelet transform). A group of Gaussian white noise as the wavelet transform coefficient of a certain scale is random produced utilizing computer. Calculate the wavelet transform coefficients of other different scales via appropriate transformation, and then the 1/f-type fractal signal can...
First, the false peak of Burg Spectrum estimation is introduced. In this paper, a new method of eliminating false peak based on Empirical Mode Decomposition is proposed. Secondly, this new method is used in the Line spectrum analysis of ship radiated noise simulation signal. Compared with traditional Linear Spectrum analysis, it is a better method for signal analysis and processing.
Feature selection plays an important role in the area of machine learning. Class Label is often used as the supervised information for supervised feature selection algorithm while constraints are rarely used. So, an effective feature selection algorithm with pairwise constraints called Constraints Score was proposed. But its performance still is limited by neglecting the correlation between features...
We calculate the Hurst exponent H(t) of several time series by dynamical implementation of a scaling technique: the detrending moving average (DMA). In order to assess the accuracy of the technique, we calculate the exponent H(t) for artificial series, simulating monofractal Brownian paths, with assigned Hurst exponents H. We next calculate the exponent H(t) for the return of high-frequency (tick-by-tick...
Exploring the factors that affect the Network Technology Resources Quality Evaluation, we establish index system of the network model and evaluation model for the Network Technology Resources Quality Evaluation by using hierarchical analysis, Gray and Fuzzy.
We present a novel method for idle and work states classification in brain computer interface (BCI) based on steady-state visual evoked potentials (SSVEP). Canonical correlation analysis (CCA) and maximum contrast combination (MCC) are used to extract features of electroencephalogram (EEG) signals. The correlation coefficients from CCA and SNR from MCC were classified by a linear classifier. Then...
Network tomography is a newly developing technology for network administrators to monitor, predict and diagnose their networks, which is applied to infer network internal parameters with end-to-end measurement under no participant and no help of internal network elements. Delay is one of important parameter in network internal performances, so the measure of delay performance is very necessary. The...
Underwater acoustic communication channels are generally characterized as seriously time-space-frequency variant channels with strong multi-path interference, limited bandwidth, severe environment noise and Doppler effect. In underwater acoustic hop frequency communication system, every user's information is modulated by a special code on the transmitter, the information will be demodulated by the...
A Real-time and reliable detection of anomalies is an important and challenging task. Unlike most detection methods based on the statistical analysis of the packet headers (Such as IP addresses and ports), we propose a new nonlinear approach only using network traffic volumes to detect anomalies reliably. Our method is based on the largest Lyapunov exponent and the change-point detection theory to...
In the crystal research the areas between different grains have great effect on the mechanic, metallurgy, corrosion properties to the material. We call these areas grain boundary. People put great emphasis on them and have tried many methods to research them. The grain boundary has high energy and the energy value is changed with the orientation. Finding the law between them can deepen the material...
In the material research we often investigate the mass transport phenomenon. As is known the mass in metals are transferred by diffusion movement. Most of the physical and chemical process is related with the diffusion phenomenon. It is the most important subject for the material science which we call it diffusion theory. Now we usually adopt the experimental method to research the diffusion in the...
How to suppress Gauss white noise that is inside the pass band of Pseudo-random code phase-modulation and pulse-doppler combined fuze is studied. According to the characteristic that Gauss white noise is stochastic, noise can be suppressed through getting the average of echo signals in several pseudo-random code cycles. The simulation results show that the ratio of maximal side lobe and main lobe...
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