基于状态观测器的新分数阶超混沌系统广义同步

研究一个新分数阶超混沌系统的非奇异矩阵系数的广义同步问题.根据实际问题需要,这个新的分数阶超混沌系统采用Caputo分数阶导数的定义.针对这个系统,设计了一个基于极点配置理论和分数阶线性系统稳定理论的状态观测器,通过配置误差系统系数矩阵极点位置,设计得到反馈矩阵L,使得观测器状态的线性非奇异变换与该分数阶超混沌系统的状态实现广义同步,从而也使这个观测器可以实现包括完全同步、反同步和投影同步等经典的同步形式,数值仿真验证了该方法的有效性.     

基于五维超混沌的全球信息栅格图像加密算法

为解决全球信息栅格的网络数据的安全问题,提出新的基于五维超混沌系统的图像加密算法,给出全球信息栅格通信体系的基于超混沌的图像加密方案.对生成的两个超混沌序列进行预处理,并置乱图像的像素位置.最后,选择一个混沌序列进行预处理后对图像像素值加密,以改变灰度值.仿真分析结果表明,该加密算法密钥空间大,密钥选择敏感,具有很高的安全性和很好的加密效果.     

一个新混沌系统

构造了一个不同于经典的Lorenz系统、Chen系统和Lü系统的三维连续自治混沌系统,利用理论分析和相图、时间响应图、Lyapunov指数谱和分岔图等非线性动力学分析方法,研究了新混沌系统的一些基本动力学特性.分析结果表明,系统是耗散的,存在两个不稳定平衡点,轨线是有界的.当参数变化时该混沌系统表现出丰富的动力学行为.     

直接序列扩频通信抗干扰性能分析

简述了直接序列扩频通信基本原理,讨论了直接序列扩频通信的特点,对直接序列扩频通信系统的抗干扰能力进行研究,最后提出了几种用于提高该通信系统抗干扰能力的具体方法.     

基于物理混沌的扩频序列的产生及其性能分析

针对当前混沌扩频序列复杂度低、产生方法单一的不足,提出了一种高效的基于嵌入式模型产生混沌扩频序列的方法,并将生成的混沌序列应用于直接序列扩频系统.理论分析和仿真表明:该方法生成的混沌序列不仅复杂度高、保密性好,具有良好的相关性能,而且能够同时产生大量的混沌扩频序列,极大地提高了生成效率,有一定的实用价值.     

一个具有四翼吸引子的超混沌系统设计与实现

为提高超混沌吸引子的拓扑结构的复杂性,构造了一个新的超混沌系统,对新的系统进行了理论分析和计算机仿真,并设计了一个模拟电路对系统进行实验,实验所得相图与数值仿真一致,是具有四翼吸引子的超混沌系统,从而证明了理论分析和数值仿真的正确性.     

预测反馈法控制高维离散混沌系统研究

针对离散混沌系统的研究,大多数集中于理论分析和数值计算,而实验方面的研究较少.为此,利用电子线路实验实现了三阶超混沌离散系统和二阶Henon映象混沌系统以及预测反馈法控制混沌和超混沌.从理论上分析了控制混沌和超混沌系统所需的条件,并通过实验进行了验证,实验结果与理论分析结果符合得很好.     

基于广义混沌同步的数字图像隐藏方案

基于广义混沌同步理论,提出了一种适于网络图像传输的隐藏数字图像的安全通讯方案.构造了一个六维广义混沌同步系统作为新方案的加密器,理论分析和计算机模拟说明本方案具有较高的保真度和较强的抗破译能力.     

基于时滞混沌系统的带密钥Hash函数的设计与分析

提出了一种基于时滞混沌系统的带密钥Hash函数算法,该算法利用时滞混沌系统非线性动力学特性,将需要传送的明文信息调制在时滞混沌迭代的轨迹中,并通过HMAC-MD5算法计算得出Hash值,Hash值的每个比特都与需传送的明文信息相关.该算法使Hash值对明文信息及时滞混沌迭代初始条件的微小变化高度敏感.理论分析和仿真结果均表明,该算法在保证Hash值的混乱性和散布性的同时,由于其混沌特性的加入而增大了参数空间,并且混沌Hash值与初始明文信息之间的非线性关系可以有效地抵御线性分析.因此,本文设计的基于时滞混沌系统的Hash函数算法具有很好的安全性、抗碰撞性和抗攻击能力,在数字签名等认证技术领域有很好的应用前景.     

自适应分数阶微分在图像纹理增强中的应用

针对目前只能通过人为实验指定最佳分数阶微分阶数的现状,为了节省大量人工寻求最佳分数阶微分阶数的时间,研究并提出了可以依据掩模窗口大小、G-L公式、图像梯度特征和人眼视觉特性等理论的能够自动生成分数阶微分阶数的新方法,基于该自适应阶数,设计并实现了对应的算子掩模.采用了信息熵、平均梯度等图像纹理特征评价参数做定量分析和实验验证,结果表明,该方法对任意灰度图像可以得到连续变化的增强效果,接近于最佳分数阶微分增强效果,符合人们的视觉感受,是有效的图像纹理增强方法.     

Body area communication based on quasi-electrostatic field and spread spectrum

Based on the electrical model of body area communication,the change tendency of channel gain in 100 kHz-10 MHz band was experimentally analyzed and verified.Results show that channel gain Was flat and signal attenuation was approximately 43 dB in 1 MHz-10 MHz band.The characteristics of the channel were taken into account in the design of body area spread spectrum communication and its multiuser receiver issue.BER-Eb/No curves of single user and multiuser were derived by simulation.The characteristics of body area commutation channel were studied and the feasibility of introducing spread spectrum theory to body area communication was verified.     

An improved method of generating the self-balanced chaotic spread-spectrum code

An improved method of generating the self-balanced chaotic spread-spectrum code is presented. The chaotic-map pseudorandom sequence is used as the generated source. After a series of process- ing two-valued quantization, inversion, all upside down, radix-S block upside down and shift combi- nation, the proposed code is achieved. Theory analysis and simulation performance of the improved code axe illustrated. And the results indicate that the suggested method gains a better performance than the traditional one by reasonable choices of the initial value and the S parameter in the im- proved method. Meanwhile the chaotic sequence' s characteristic of large addresses is inherited when the chaotic-map is used as the source. This advantage makes this improved code very suitable for the multiple access application in communication system.     

Nonuniformity in the linear network model of the oculomotor integrator produces approximately fractional-order dynamics and more realistic neuron behavior

The oculomotor integrator is a network that is composed of neurons in the medial vestibular nuclei and nuclei prepositus hypoglossi in the brainstem. Those neurons act approximately as fractional integrators of various orders, converting eye velocity commands into signals that are intermediate between velocity and position. The oculomotor integrator has been modeled as a network of linear neural elements, the time constants of which are lengthened by positive feedback through reciprocal inhibition. In this model, in which each neuron reciprocally inhibits its neighbors with the same Gaussian profile, all model neurons behave as identical, first-order, low-pass filters with dynamics that do not match the variable, approximately fractional-order dynamics of the neurons that compose the actual oculomotor integrator. Fractional-order integrators can be approximated by weighted sums of first-order, low-pass filters with diverse, broadly distributed time constants. Dynamic systems analysis reveals that the model integrator indeed has many broadly distributed time constants. However, only one time constant is expressed in the model due to the uniformity of its network connections. If the model network is made nonuniform by removing the reciprocal connections to and from a small number of neurons, then many more time constants are expressed. The dynamics of the neurons in the nonuniform network model are variable, approximately fractional-order, and resemble those of the neurons that compose the actual oculomotor integrator. Completely removing the connections to and from a neuron is equivalent to eliminating it, an operation done previously to demonstrate the robustness of the integrator network model. Ironically, the resulting nonuniform network model, previously supposed to represent a pathological integrator, may in fact represent a healthy integrator containing neurons with realistically variable, approximately fractional-order dynamics.     

代码生成技术在通信接口开发中的应用

在分析代码生成基本技术原理的基础上,针对冶金行业过程自动化系统与管理信息系统间通信接口开发的具体应用,探讨基于代码转换技术和基于CoreSip通信平台的代码生成技术。     

利用OPC实现VC应用程序与WinCC的数据交换

本文基于OPC(OLE for Process Control)技术的基本原理,重点介绍了通过组态软件WinCC实现VC应用程序与一级自动化系统的通讯方法.详细介绍了WinCC作为OPC服务器的设置方法和VC编写OPC客户端程序的实现代码.     

Biological activity and brain actions of recombinant rat interleukin-1alpha and interleukin-1beta

An HMQC experiment is proposed, dubbed FHMQC, where water flip-back is achieved by a single water-selective pulse preceding the basic HMQC pulse sequence. The scheme is demonstrated with a 15N,1H-HMQC spectrum of uniformly 15N/2H-labelled S. aureus DNA gyrase B with a molecular weight of 45 kDa for the unlabelled protein. The sensitivity of the experiment is improved compared to that of an FHSQC spectrum. It is further shown that the original FHSQC experiment can be shortened by the use of bipolar gradients. Relaxation times of different 15N magnetizations and coherences were measured. The new FHMQC scheme is implemented in 3D NOESY-15N-HMQC and 3D 15N-HMQC-NOESY-15N-HMQC pulse sequences which are demonstrated with a 24 kDa fragment of uniformly 15N/13C/2H-labelled S. aureus DNA gyrase B.     

Robust Fractional-Order PI Controller Implemented on a Laboratory Hydraulic Canal

This paper deals with the development of a new robust fractional-order PI controller for hydraulic canals whose parameters can vary in a wide range. Robustness to gain changes has particularly been increased. A method to design these controllers through the use of frequency specifications is proposed. Analysis of the frequency response of the closed-loop canal shows that the general robustness was also enhanced. Two of these fractional controllers have been experimentally implemented in a laboratory hydraulic canal characterized by time-varying dynamical parameters. A comparison between the real-time responses of the fractional-order control system and those of the standard PI demonstrates the effectiveness of the proposed fractional-order control strategy in terms of performance and robustness.     

Microsatellite mutation rates in cancer cell lines deficient or proficient in mismatch repair

A selectable system has been used to determine mutation rates within a microsatellite sequence in human cancer cell lines with or without defects in mismatch repair. A sequence consisting of 17 repeats of poly (dC-dA).poly(dT-dG) [abbreviated as (Ca)17] was inserted near the 5' end of the bacterial neomycin-resistance gene in a plasmid vector, such that the reading frame of the neo gene is disrupted. This plasmid was introduced into cancer cell lines, where it became integrated into the cellular genome. Clones with insertions or deletions of CA-repeats that restored the normal reading frame of the neo gene were selected in G418, and mutation rates were determined by fluctuation analysis. The rates of reversion in LoVo cells, which are deficient for hMSH2, were about one in a thousand per generation, which is approximately two orders of magnitude higher than in the repair-proficient HT-1080 human fibrosarcoma cell line. The mutation rates in H6 cells, which are derived from the hMLH1-deficient HCT116 line, were more heterogeneous than in LoVo, but all were considerably higher than in the repair-proficient line. Nearly all of the revertants of the repair-deficient lines had deletions of a single CA-repeat from the microsatellite sequence, whereas repair-proficient cells had a broader spectrum of mutations.     

A GNSS Signal Blind-decoding Algorithm at Low SNR

The pseudo-random noise (PRN) code modulated in satellite navigation signals impacts the system positioning performance directly, and the code monitoring is one of the key technologies. However, the received signal is often buried in noise, and the ranging codes can not visible in time domain. Considering local clock bias, the signal model in transmis-sion link is derived in this paper, and a PRN code blind-decoding method is proposed also. It calculates the signal' s cyclic spectrum by using fast Fourier transform accumulation method (FAM) , and estimates the code rate and Doppler frequency making use of the noise eliminating characteristic in non-zero cycle frequency cross-section. Wiped off the Doppler shift,the navigation message or secondary code bits are determined and removed by slide-correlating a small slice of itself with the whole data. The start of the code is determined by stacking multiple periods of the whole data into a code period, and then the whole data is shifted to the start of the PRN code, and is restacked. Then the individual period of PRN code is esti-mated. An experiment for the proposed algorithm is performed by simulated vector signal analyzer (VSA) collected data.The results indicate that the algorithm is effective and reliable.     

特钢棒材标记方案设计与信息码识别

为了解决特钢棒材信息跟踪的问题,提高生产智能化水平,搭建了基于机器视觉的特钢棒材端面信息码识别系统。根据车间环境和特钢棒材端面特征,提出了水平双标志点的标记方案,并针对该标记方案提出了一种信息码图像识别方法。该识别方法提取了字符二值图像灰度共生矩阵与区域连通域面积两组特征,建立特征模板库,利用特征模板库对特钢棒材端面信息码进行识别。结果表明,基于水平双标志点的标记方案能够满足特钢棒材身份标记需求,信息码图像识别方法可有效解决特钢棒材端面信息码的自动识别问题,提高钢厂自动化和智能化水平。