基于FPGA的Fm2域椭圆曲线点乘的快速实现

椭圆曲线点乘的实现速度决定了椭圆曲线密码算法（ECC）的实现速度。采用蒙哥马利点乘算法,其中模乘运算、模平方运算采用全并行算法,模逆运算采用费马·小定理并在实现中进行了优化,完成了椭圆曲线点乘的快速运算。采用Xilinx公司的Virtex-5器件族的XCV220T作为目标器件,完成了综合与实现。通过时序后仿真,其时钟频率可以达到40MHz,实现一次点乘运算仅需要14.9μs。     

基于FPGA的Fm2域椭圆曲线点乘的快速实现

椭圆曲线点乘的实现速度决定了椭圆曲线密码算法(ECC)的实现速度.采用蒙哥马利点乘算法,其中模乘运算、模平方运算采用全并行算法,模逆运算采用费马·小定理并在实现中进行了优化,完成了椭圆曲线点乘的快速运算.采用Xilinx公司的Viaex-5器件族的XCV220T作为目标器件,完成了综合与实现.通过时序后仿真,其时钟频率可以达到40 MHz,实现一次点乘运算仅需要14.9μs.     

高效椭圆曲线密码芯片的VLSI设计

根据素数域上椭圆曲线的点乘，提出了一种椭圆曲线密码芯片VLSI新结构和控制算法。针对其中的核心运算模乘，结合Montgomery算法，提出了一种改进的模乘器结构，有效降低了芯片的面积，提高了模乘的运算速度。该芯片具有面积小、速度快的优点，适合用于时钟频率低和存储空间受限的智能卡中。     

基于椭圆曲线的数字签名系统的设计与实现

基于椭圆曲线的数字签名系统是目前主流的数字签名系统之一,并且被认为是经典的RSA系统的最佳替代者。基于椭圆曲线离散对数问题的数字签名系统使用的签名协议主要来自于签名等式的不同变形,通过对协议进行面向实现的优化可以使整个系统更加高效。在协议的实现过程中底层算法对系统的效率有着至关重要的影响。基于椭圆曲线的数字签名系统主要包括两个层次的底层运算:椭圆曲线上点的运算;有限域上元素的运算。对曲线上点的运算的优化主要是通过对标量乘算法和曲线上点的坐标系统的优化(减少求元素逆的操作)实现的,对有限域上元素运算的优化主要是通过使用类Mersenne素数模数优化求模操作,从而加快模乘和模平方操作。经过以上优化设计与实现的系统比以往实现的系统更加高效。     

素数域椭圆曲线密码系统算法实现研究

针对素数域椭圆曲线密码系统的算法高速实现，分别讨论了对椭圆曲线上的点的加法和倍点运算。以及对点的标量乘法运算进行优化的技术，同时给出了测试比较结果，说明了所讨论的优化技术可以大大提高整个椭圆曲线密码系统的算法实现性能。     

基于Kogge-Stone加法器改进的双域模乘器

模乘作为椭圆曲线公钥密码算法的核心运算,调用频率最高,提高其运算速度对于提高椭圆曲线密码处理器的性能具有重要意义。基于Kogge-Stone加法结构,结合可重构技术,实现一种能够同时支持素数域GF(p)和二元域GF(2~m)上模乘运算的双域模乘器,并对模块进行合理复用,节省硬件资源。用Verilog VHDL语言对该模乘器进行RTL级描述,并采用0.18μm CMOS工艺标准单元库进行逻辑综合。实验结果表明,该双域模乘器的最大时钟频率为476 MHz,占用硬件资源66 518 gates,实现256位的模乘运算仅需0.27μs。     

素数域椭圆曲线密码在智能卡上的设计与实现

椭圆曲线密码体制具有密钥短,安全性高的特点,十分适合在智能卡上使用.针对智能卡存储与计算能力有限的特点,分析了选择素数域椭圆曲线密码的原因,并提出一种基于RSA基本运算的ECC实现方案.通过该方案,可以利用已有的RSA智能卡平台所提供的运算协处理器实现素数域上的ECC算法.详细分析了椭圆曲线密码实现过程中的各个细节,并针对倍点与点加这两个基本运算,设计出针对智能卡的实现方案,该方案可以最大程度节省智能卡存储空间.最后给出了素数域椭圆曲线签名算法在智能卡上实现的实验数据,证明设计的实现方案是高效的.     

基于智能卡的素数域椭圆曲线密码的快速实现

椭圆曲线密码相比其它公钥密码,有密钥短的特点,尤其适合在智能卡等资源受限的条件下使用。文章指出了在智能卡平台上选择素数域为基域实现椭圆曲线密码的原因。并详细分析了椭圆曲线密码实现过程中的各个环节,包括标量乘法运算、点加/倍点运算和基域运算,指出了各个环节的优化措施。最后给出了素数域椭圆曲线签名算法在智能卡上实现的实验数据,实验结果证明文中采用的实现方法是高效的。     

素数域椭圆曲线密码加速器的VLSI实现

分析了素数域椭圆曲线密码（ECC）算法的软件效率,针对软件效率较低的问题,对密码系统进行软硬件划分,提出了一种适用于椭圆曲线密码SoC的硬件加速器设计,并设计了密码SoC的结构。硬件加速器实现了素数域的点乘和素数检测,以少量的面积为代价提升了系统性能。密码芯片实现了SM2商用密码标准规定的6种算法。加速器基于HJTC [0.11 μm] eFlash单元库,面积约为[0.6 mm2]。在50 MHz的频率下,192 bit非固定点乘运算性能为167次/s,256 bit非固定点乘运算性能为94次/s。实验结果表明,该加速器的单位面积性能高于其他同类设计。     

前向安全的椭圆曲线数字签名方案

将椭圆曲线密码体制的优势与前向安全的概念相结合,在椭圆曲线数字签名算法(ECDSA)的基础上,引入系统时间划分方法来减少密钥泄露带来的损失,从而构造出一种基于椭圆曲线的前向安全的签名方案(改进方案)。安全性分析表明,该方案不仅可以抗随机数攻击,而且在随机预言模型下基于椭圆曲线离散对数问题(ECDLP)困难性是前向安全的。算法运算量分析表明,在签名生成和验证时,改进方案比ECDSA方案少了1次倍点运算、2次模乘运算和2次模逆运算。MATLAB仿真结果表明,在签名效率上,改进方案比ECDSA方案以及同样具有前向安全性的周克元方案都要高。     

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。     

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.     

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.     

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     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.