脉冲位置键控系统误比特性能分析

梳理基于等待门限判决的脉冲位置键控系统相关文献资料,发现文献给出的误比特率(BER)理论公式不能准确描述系统误比特率,尤其是在低信噪比情况下一些理论公式计算的误比特率已经高于0.5,超过了通信系统误比特率上限,不符合通信理论。分析了各文献资料误比特率理论公式推导过程中的问题所在,推导得到了一个新的误比特率理论公式。进行了数值仿真,结果表明,新的误比特率理论公式与仿真吻合良好,能够准确描述系统误比特率,并且在低噪比下计算的误比特率不高于0.5,符合通信理论。在新的误比特率理论公式基础上,分析了基于等待门限判决的脉冲位置键控系统能量效率,并与二进制相移键控(BPSK)系统进行了比较,表明基于等待门限判决的脉冲位置键控系统是一种具有较高能量效率的系统,在一定条件下甚至优于BPSK系统。     

Video fragment format classification using optimized discriminative subspace clustering

All video streams consist of highly compressed coded data. A video stream must be decoded to identify a video. It is impossible to decode and identify a video fragment without knowing the correct video format. Therefore, the first issue that must be addressed is classification of video formats. Although several methods exist for classifying file formats, a technology that specifically classifies the formats of video fragments has not been developed. In this paper, we present a novel approach to classify the formats of small fragments of video streams. Our classification procedure involves construction of high-dimensional feature vectors by combining synchronization patterns extracted from training fragments. The feature vectors are classified using optimized discriminative subspace clustering (ODiSC). The experimental results show a minimum classification error rate of 4.2%, and the precision of identification of the formats was greater than 91% for the four video formats whose fragment size was 256 KB.     

Interplay of noise and coupling in heterogeneous ensembles of phase oscillators

We study the effects of noise on the collective dynamics of an ensemble of coupled phase oscillators whose natural frequencies are all identical, but whose coupling strengths are not the same all over the ensemble. The intensity of noise can also be heterogeneous, representing diversity in the individual responses to external fluctuations. We show that the desynchronization transition induced by noise may be completely suppressed, even for arbitrarily large noise intensities, is the distribution of coupling strengths decays slowly enough for large couplings. Equivalently, if the response to noise of a sufficiently large fraction of the ensemble is weak enough, desynchronization cannot occur. The two effects combine with each other when the response to noise and the coupling strength of each oscillator are correlated. This combination is quantitatively characterized and illustrated with explicit examples.     

存在参数微扰的非自治超混沌系统的同步

本文对四维非自治的超混沌光学模型的同步问题进行了讨论。结合误差反馈同步方法和参数自适应同步方法,使参数不同的两个系统达到同步,数值计算结果也表明同步效果很好。同时对控制函数的参数与同步建立的时间两者之间的关系进行了仿真,结果表明,存在最佳参数使得同步建立的时间最短。     

Nonlinear electronic circuit, Part II: synchronization in a chaotic MODEM scheme

In this work we present a thorough investigation of the effect of noise (internal or external) on the synchronization of a drive-response configuration system (unidirectional coupling between two identical systems). Moreover, since in every practical implementation of a communication system, the transmitter and receiver circuits (although identical) operate under slightly different conditions it is essential to consider the case of the mismatch between the parameters of the transmitter and the receiver. In our work we consider the non-autonomous 2nd order nonlinear oscillator system presented in [G. Mycolaitis, A. Tamasevicious, A. Cenys, A. Namajunas, K. Navionis, A. N. Anagnostopoulos, Globally synchronizable non-autonomous chaotic oscillator, in: Proc. of 7th International Workshop on Nonlinear Dynamics of Electronic Systems, Denmark, July 1999, pp. 277-280] which is particularly suitable for digital communications.Furthermore, we modified the previous chaotic communication system in order to exhibit enhanced security features. The enhancement in the security of the system is achieved by introducing a set of parameters used in the encoding and decoding of the message signal. We also introduce a time delay parameter in the dynamical system which on the one hand improves the chaotic behavior of the system and on the other hand, adds further security in the encoding-decoding scheme.     

PTN承载网同步传送方案

简要介绍了时钟和日寸间2种同步技术,重点阐述了PTN承载网同步技术方案、时钟保护和规划设计原则。     

Signal Synchronization Using a Flicker Reduction and Denoising Algorithm for Video‐Signal Optical Interconnect

A video signal through a high‐density optical link has been demonstrated to show the reliability of optical link for high‐data‐rate transmission. To reduce optical point‐to‐point links, an electrical link has been utilized for control and clock signaling. The latency and flicker with background noise occurred during the transferring of data across the optical link due to electrical‐to‐optical with optical‐to‐electrical conversions. The proposed synchronization technology combined with a flicker and denoising algorithm has given good results and can be applied in high‐definition serial data interface (HD‐SDI), ultra‐HD‐SDI, and HD multimedia interface transmission system applications.     

Synchronized stability in a reaction–diffusion neural network model

The reaction–diffusion neural network consisting of a pair of identical tri-neuron loops is considered. We present detailed discussions about the synchronized stability and Hopf bifurcation, deducing the non-trivial role that delay plays in different locations. The corresponding numerical simulations are used to illustrate the effectiveness of the obtained results. In addition, the numerical results about the effects of diffusion reveal that diffusion may speed up the tendency to synchronization and induce the synchronized equilibrium point to be stable. Furthermore, if the parameters are located in appropriate regions, multiple unstability and bistability or unstability and bistability may coexist.     

祖冲之算法分析及其硬件实现

详细分析了3GPP LTE国际加密标准祖冲之(ZUC)算法的结构及其硬件实现过程.ZUC流式加密算法采用了线性反馈移位寄存器(LFSR),比特重组(BR)和非线性函数F的三层结构设计,具有很高的安全性.同时,ZUC算法在设计时就充分考虑了软硬件实现的低复杂度,因此非常适合于硬件实现.ZUC算法在Altera的Cyclone FPGA上实现,需要2 013个逻辑单元,不需要存储器.在中芯国际SMIC 0.18 μm的CMOS工艺上实现的芯片面积为109 823 μm2.