Papers by Keyword: Self-Similar

Abstract: The random access technique has a bigger influence to the performance optimization of CDMA data traffic. A CDMA random access technique based on self-similar model and its performance analysis are put forward in this paper. The simulation results indicate that the access performance of CDMA data traffic based on self-similar model is attenuated by power law, related to such parameters as fractal coefficient H and network load G. The CDMA traffic access self-similar equalization protocol (TASEP) is put forward and it can improve the access performance of CDMA data traffic distinctly.

Abstract: This paper proposes an improved acquisition method for high-order binary-offset-carrier (BOC) modulated signals based on fractal geometry. We introduced the principle of our acquisition method, and outlined its framework. We increase the main peak to side peaks ratio in the BOC autocorrelation function (ACF), with a simple fractal geometry transform. The proposed scheme is applicable to both generic high-order sine-and cosine-phased BOC-modulated signals. Simulation results show that the proposed method increases output signal to noise ratio (SNR).

Abstract: To improve the robustness of watermarking algorithms, this paper proposes a robust digital watermarking algorithm based on combination of fractal and wavelet. By key the algorithm transfers watermark information into self-similar fractal images, discretes Haar wavelet to host image, and embeds two fractal watermark image after fractal into Haar wavelet sub-band. Simulation results show that the algorithm has good robustness to image distortion as noise, JPEG compression, shear, filtering, etc.

Abstract: With the popularity of internet and the growing of applications in recent years, network traffic characteristics are also undergone a great change. The traditional flow models are unable to meet the current traffic. Therefore, it is done to study the law of current traffic model, to propose these models of service traffic characteristics and to explore the applications of these models in practice.

Abstract: This paper introduces the phenomenon of self-similar network, and then it gives the mathematical definition of self-similar and analysis for the network performance. Based on this, this paper puts forward a new mapping model of ON / OFF and the chaotic mapping model based on the ideas. The model simplifies the chaotic mapping function mapping model by choosing a random variable with a linear piecewise function. The model length is subject to the state heavy-tailed. This model can capture network traffic self-similarity.

Abstract: A fractal is a property of self-similarity, each small part of the fractal object is similar to the whole body. The traditional box-counting method (TBCM) to estimate fractal dimension can not reflect the self-similar property of the fractal and leads to two major problems, the border effect and noninteger values of box size. The modified box-counting method (MBCM), proposed in this study, not only eliminate the shortcomings of the TBCM, but also reflects the physical meaning about the self-similar of the fractal. The applications of MBCM shows a good estimation compared with the theoretical ones, which the biggest difference is smaller than 5%.