A new threshold function was proposed to overcome that hard threshold function is not continuous, soft threshold function has constant deviation and derivative discontinuity defects. It will be applied to using different thresholds denoising method with different decomposition level based on the D.J global threshold. Experimental results shows that the denoising result of new threshold function is superior to the traditional soft and hard threshold function in minimum mean square error (MSE) and peak signal to noise ratio (PSNR).
There exists a problem of endpoint effect in EMD, which makes the result of decomposition not perfect. The paper comes up with a kind of envelope correction method to suppress the endpoint effect on this question about periodical signal. The result shows that, the method can solve the problem on distortion of envelope, and improve the accuracy of decomposition.
The paper proposes a particle pair optimization (PPO) algorithm for numerical optimization. In the paper, a particle pair search(PPS) is designed. Based on PPS, the competitive roulette strategy is employed to the selection of particle pair from swarm, and a particle pair optimization algorithm is proposed. In the experiments, PPO is applied to solve the 12 benchmark problem, and compared with fast evolutionary programming (FEP). The results demonstrate that PPO algorithm can find optima or close-to-optimal solutions of the complex functions with high-dimension, and the search of PPO is stable and efficient.
Wigner-Vill distribution (WVD) will inevitably have cross-terms when it used for time-frequency representation in a multi-component signal. In order to suppress the cross-terms in Wigner-Vill distribution, this paper proposes a joint algorithm based on EMD-ICA. This algorithm resolves a multi-component signal into several IMF components used by EMD at first, and then each IMF component is used FastICA algorithm for processing, and next seeks the Wigner-Vill distribution of each component, finally, add up the results. This method effectively inhibited the emergence of cross-terms in Wigner-Vill distribution, and keeps the properties of time-frequency concentration higher.
This paper proposed a new software-based Content Distribution Network (CDN) model. First, we overviewed some related technologies of CDN. Then, software CDN model was built, and the key strategies of load balancing, content distribution and file transfer were explored in the software CDN model. Also in this model, the load balancing algorithm based on load equilibrium with latency and the content distribution algorithm of the non-hot media based on Markov prediction were discussed in detail. Finally, an on-demand video system was designed to verify the feasibility of the proposed model.
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