混沌二进制序列的伪随机性和复杂性分析

分析和讨论了由经典的Lorenz混沌系统和Chebyshev映射所生成的二进制序列的伪随机性和复杂性,采用T.Kohda混沌二进制量化算法,将混沌系统所产生的实数序列转换为相应的二进制序列;从统计检验、自相关性、频谱、Lempel-Ziv复杂度和近似熵等多方面对序列的伪随机性和复杂性进行定量分析。统计分析结果表明对由混沌系统所产生的有限二进制序列逼近Lempel-Ziv意义的随机序列,它具有较高的伪随机性、复杂性和非周期性,但是序列的伪随机性和复杂性并不随序列长度的增加而提高,在近似熵评价指标中呈显出降低的趋势。同时,作为伪随机源,Lorenz混沌系统略比Chebyshev映射好。     

基于混沌伪随机序列发生器的图像加密方法

提出了一种基于两个参数随机变换的混沌系统的伪随机序列发生器，生成一个随机性好、周期长的密钥序列并给出了统计特性分析的严格的理论证明。用此序列进行图像加解密实验，结果分析表明，提出的算法能够得到令人满意的加密效果。     

基于双混沌系统的序列加密方法研究

由于混沌系统对初始条件和混沌参数非常敏感以及生成的混沌序列具有非周期性和伪随机性的特性,近年来在信息加密领域得到了较多的应用。但是大多数混沌序列发生器都是采用单混沌系统,可能存在一些潜在的动力学系统攻击方法。提出了一种基于两个参数随机变换的混沌系统的伪随机序列发生器,生成一个随机性好、长周期的密钥序列,并给出了统计特性分析的严格的理论证明。理论分析表明此密钥序列具有较高的线性复杂度和良好的密码学特性。     

量化压缩感知在语音压缩编码中的应用

利用语音信号在离散余弦变换（ DCT）域的近似稀疏性和量化压缩感知理论,文中提出一种基于量化压缩感知的语音压缩编码方案。编码端利用压缩感知技术,将语音信号投影成数据量大大减少的观测序列,然后对观测序列采用Lloyd-Max量化得到量化后的观测样值;解码端直接利用量化后的观测样值,结合重构算法重构出原始语音信号的DCT系数,经过DCT反变换得到重构后的语音信号,并采用后置低通滤波器改善重构语音的听觉效果。该编码方案解码端不需要进行反量化,而是直接利用量化后的观测样值进行重构,有效降低了解码端的运算量及复杂度。仿真结果表明：采用量化迭代硬阈值（QIHT）算法重构效果优于迭代硬阈值算法（IHT）,重构语音的信噪比能达到20 dB以上,MOS分达到3.26。     

基于双混沌映射的图像加密算法

提出了一种基于Logistic和Henon混沌映射的图像加密方法.首先利用Logistic混沌动力学系统产生的混沌序列,通过动态量化算法增强其随机性和复杂性,对原始图像进行混沌置乱,得到置乱图像.然后对Henon混沌映射产生的序列进行量化变换,产生"异或"矩阵,与置乱后的图像进行"异或",实现对图像的加密.仿真实验表明,该方法具有良好的加密效果和较强的安全性.     

伪随机序列的产生与随机性测试

介绍了伪随机序列的原理以及随机性测试的基本方法,提供了5种方法,并建立模型以便对所有的序列进行检测,对生成的m和Gold序列进行随机性检测,并将文本文件以二进制的方式读取,对得到的序列进行上述5种检测.     

基于Hilbert扫描和小波变换的自适应图像分割

阈值的选择是图像阈值分割法的关键,针对现有阈值法中存在的没有充分地考虑图像像素之间的空间相关信息等问题,提出把Hilbert图像扫描方法和小波变换相结合,获得了连续光滑的阈值曲线,从而建立了一种局部自适应阈值法。首先通过Hilbert图像扫描的方法将2维图像信息转化为1维Hilbert序列;然后利用小波变换对其进行多分辨分析获得信号的发展趋势曲线,并将该曲线作为阈值曲线对Hilbert序列进行量化处理;最后对量化后的Hilbert序列运用Hilbert图像扫描的反过程恢复为2维图像信息,从而实现原图像的分割。该方法所建立的阈值曲线能够随像素点的环境变化而自适应调整,反映出当前区域图像灰度信息的变化趋势,从而充分地保留了图像的局部信息和原图像中相邻像素的相关性,提高了图像分割效率。实验结果表明,该方法具有分割性能好以及受噪声影响小等优点,是一种非常有效的图像分割方法。     

基于SVM的0-1序列生成器

提出一种0-1序列生成器的设计方法。该方法通过Logistic映射得到一组对初始值具有敏感性、快速衰减的自相关性、长期不可预测性和伪随机性的随机序列;利用SVM对随机序列进行粗粒化,由于SVM的确定性和不改变随机序列的时序性,生成0-1随机序列。理论研究和数值模拟表明,该序列发生器具有良好的随机性,并且易于实现。     

半空间混合图像置乱方法

考虑到变换域置乱的鲁棒性和混沌序列对初值敏感、遍历性及随机性等特点,提出一种基于DCT变换域的半空间图像置乱方法,先对图像的第一个变量进行一维DCT变换。在此基础上对DCT系数用混沌序列进行调制,将调制结果进行DCT反变换;进而对图像的第二变量进行一维DCT变换,采用与第一变量相同的方法得到最终的置乱结果。算法简单可行,置乱效果好。实验证明该方法具有一定的抗攻击能力。     

TDCS伪随机相位生成法及其改进

针对变换域通信系统中利用传统伪随机相位生成法所得的基函数随机性较弱且相关性较差的问题,提出了一种采用混沌映射m序列控制的伪随机相位生成法,相比于传统相同长度一维m序列产生的基函数,所产生的基函数随机性提高了N倍(N为m序列的长度);同时又由于采用混沌映射,产生的基函数互相关系数很小且可选数量很大.仿真结果表明,采用混沌映射m序列控制法生成的基函数,其随机性与相关性同时得到了提高,从而有效地降低了TDCS的误码率.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.