Applied Mechanics and Materials Vols. 333-335

Abstract: Our country has rich coal resources. Further research is great significant to realize the automation of top coal caving mining technology. This paper presents a new method based on sparse representation for coal and gangue signal recognition. To solve the mining noise problem, the wavelet analysis is used to filter and de-noising. Sparse representation classification is based on the theory of compressed sensing. Recognition is achieved by analysis the sparse vector that the linearly optimal representation for a testing sample based on the training sample. Experimental results performed the method is accurate and stable.

Abstract: The research in bearing fault diagnosis has been attracting great attention in the past decades. Development of feasible fault diagnosis procedures to prevent failures that could cause huge economic loss timely is necessary. The whole life of the bearing is also a developing process for some sensitive features related to the fault trend. In this paper, a new scheme based on ensemble empirical mode decomposition (EEMD) and support vector regression (SVR) to conduct bearing fault degree recognition is proposed. This analysis first extracts the sensitive features from the intrinsic mode functions (IMFs) produced by EEMD which is a potential time-frequency analysis method, and then constructs an intelligent nonlinear model with input feature vectors extracted from the IMFs and defect size as output. Through validation of experimental data, the results indicated that the bearing fault degree could be effectively and precisely recognized.

Abstract: In order to understand the transmission mechanism at human tissue of near-infrared square-wave pulse (NIRSP), an experimental study of the duty ratio threshold for regular transmission at the fingertip and palm of human hand by NIRSP was carried out by using a couple of simple transmitting and receiving device with tunable duty ratios, and also the light emitting diodes (LED) both at the wavelengths of 850 nm and 940 nm. The thresholds were determined by measuring the waveforms of the changed voltages of NIRSP receiving system as a measurement of the transmission at human tissue. When the receiving waveforms were taken on the certain behavior as the emitting waveforms, the duty ratio threshold for regular transmission at human tissue of NIRSP was observed. The experimental results show that the duty ratio is an important index for the transmission at human tissue of NIRSP. And the duty ratio thresholds for regular transmission both at the fingertip and palm of NIRSP at the wavelength of 850 nm and 940 nm have been given.

Abstract: Stochastic resonance (SR) enhances the nonlinear system behavior with the assistance of noise. The energy-transfer mechanism makes the weak information revealed in the output spectrum, while the time-waveform is distorted. The stochastic resonance recovery parameters normallization was derived, and which is proved to be true through the circuit numerical simulations applications.

Abstract: A new method for two-dimensional barcode encryption through using improved chaotic sequences of logistics has been proposed. The image of two-dimensional barcode was divided into two parts and chaotic sequence for encryption with the two parts was used respectively. Experiments results denoted that five key ensured the encrypted image higher security. The MSE between the original image and the encrypted image is 3.49×106. Computer simulations are presented to verify its good resistance to salt and pepper noise.

Abstract: Signal recovery is a key issue in compressed sensing field. A new greedy reconstruction algorithm termed Optimised Stagewise Orthogonal Matching Pursuit (OSOMP) is proposed, which is an improved version for Stagewise Orthogonal Matching Pursuit (StOMP). In preselection step, OSOMP chooses several coordinates with a calculated threshold to accelerate the convergence of algorithm. In following pruning step, a small proportion of selected coordinates are discarded according to the amplitude of estimated signal, thus most false discovered coordinates can be swept away. Experimental results show that in OSOMP, the scale of estimated support can be controlled very well, and the successful recovery rate is also much higher than that in StOMP.

Abstract: This paper analyzes the radar anti-jamming adaptive antenna beamforming algorithm, orthogonal subspace projection algorithm used in radar anti-jamming eigenvectors in the process can not be completely orthogonal subspace decomposition, constraints annihilatorspace decomposition algorithm to ensure orthogonal subspace eigenvectors. Finally, the simulation proved: subspace tracking algorithm has stronger anti-interference performance relative to the traditional adaptive algorithm.

Abstract: In modern warfare, electronic jamming air defense missile weapon system is the greatest threat to the seeker for terminal guidance radar interference is an important aspect of electronic interference. Successful interference allows the weapon system hit rate to reduce or even out of control. Therefore, analysis of the impact of interference on radar seeker to intercept and track the performance of meaningful analysis and modeling, this paper mainly targeting blanket jamming interference and interference conditions of the monopulse system radar seeker performance were analyzed.

Abstract: In order to broaden the visual range of the 3D screen, the authors of this paper extract the characteristic values of the steady-state visual evoked potential by combining the methods of wavelet analysis, superposition average and FFT. It is illustrated by experiment that, although the amplitude changes, the characteristic values can be exactly extracted when wearing 3D polarized light glasses, so that the range of the 3D screen can be successfully broadened.

Abstract: Beam signal stretch is significant for bunch-by-bunch position measurement on storage ring in SSRF. This paper deduced a new expression to get beam position according to the relationship between BPM signals and beam position. The simulation has been done to stretch the BPM signal using square processing with matlab/simulink tool. The comparison is given between square process and original difference over sum method(Δ/Σ) using data acquired by oscilloscope and off-line processing.