适用于CCSDS标准的RS(255,223)码编码器设计*

研究了在CCSDS标准下RS编码器的时域编码方法。分析了RS码的编码原理,基本单元电路设计,包括有限域加法器和乘法器,并着重阐述了自然基下常系数并行乘法器的实现方法。在此基础上,选用系数对称的生成多项式,在QuartusⅡ5.0编译环境下设计了RS(255,223)对称结构的编码器,节约了硬件资源,给出了仿真结果图,经检验输出结果正确。采用此方法设计的RS(255,223)编码器具有控制单元简单、模块结构规则,易于FPGA实现,可用于高速场合等特点。     

一类有限域的高效部分并行乘法器

提出了一类新的具有高度规则性的部分并行三项式有限域乘法器架构。通过对由不可约三项式生成的有限域GF(2m)上的乘法分析,推导出基本的运算形式。基于该运算形式,设计出新颖的乘法器架构。复杂度分析结果表明,该乘法器具有同当前最优设计相同的复杂度。而且,可视具体的应用情境需求对乘法器电路进行灵活配置。     

GF(2~m)域乘法器的快速设计及FPGA实现

有限域GF(2m)上的椭圆曲线密码体制以其密钥短、安全强度高的优点获得了广泛的重视和应用,该密码体制最主要的运算是有限域上的乘法运算。该文提出一种基于FPGA技术的多项式基乘法器的快速设计方法,并给出了面积与速度的比较分析。     

GF(2m)域上Ⅱ型最优正规基的字级乘法器

通过研究Ⅱ型最优正规基及重序正规基之间的关系及特点,提出了一种GF(2m)域上Ⅱ型最优正规基字级乘法器.该型乘法器比串行结构乘法器更快速,比并行结构乘法器更节省资源;算法针对字级结构进行了最优,相比其他字级结构乘法器具有更小的空间复杂度.实验表明,该乘法器可以获得很高的时钟频率,且不受运算字长的影响.     

GF(2~m)上椭圆曲线密码体制的硬件实现

特征为2的有限域GF(2m)较适合椭圆曲线密码算法的硬件实现。该文通过对GF(2m)上模运算的分析,将所有的模运算转化成模乘和模加,并对LSD乘法器的进行了改进,所设计的运算单元能进行GF(2m)上所有的模运算,利用该运算单元所实现的椭圆曲线密码算法具有面积小,速度快的优点,适合用于处理能力和存储空间受限的设备中。     

基于FPGA的流水线单精度浮点数乘法器设计

针对现有的采用Booth算法与华莱士(Wallace)树结构设计的浮点乘法器运算速度慢、布局布线复杂等问题,设计了基于FPGA的流水线精度浮点数乘法器。该乘法器采用规则的Vedic算法结构,解决了布局布线复杂的问题;使用超前进位加法器(Carry Look-ahead Adder,CLA)将部分积并行相加,以减少路径延迟;并通过优化的4级流水线结构处理,在Xilinx~ISE 14.7软件开发平台上通过了编译、综合及仿真验证。结果证明,在相同的硬件条件下,本文所设计的浮点乘法器与基4-Booth算法浮点乘法器消耗时钟数的比值约为两者消耗硬件资源比值的1.56倍。     

一种基于复合域的ECC的快速乘法器

基于有限域上椭圆曲线公开密匙协议的离散对数计算算法正日益成为热点,而有限域上的计算尤其是乘法计算极大地影响其加/解密速度。基于ECC中有限域乘法的重要性,该文给出了一种复合域GF((2m1)m2)上的快速乘法器。该乘法器采用并行计算和串行计算相结合的原则,增加少量硬件规模将一次有限域乘法的计算速度由原来的m=m2m1个时钟周期降低到m2个时钟周期,从而极大地提高了乘法器的计算速度。     

基于RS码的可重构有限域乘法器的设计与实现

为了提高伽罗华有限域乘法器的通用性,降低实现的复杂度,采用自然基算法,用简单的逻辑门电路实现乘法运算过程。提出可重构的迭代计算结构,能满足域长m为3～8的乘法器,并用FPGA实现。结果表明,可重构有限域乘法器能够满足多种标准RS码的乘法运算的需要。     

有限域GF(2m)上基于基转换的正规基快速求逆方案

有限域GF(2m)在椭圆曲线密码体制中有着非常重要的应用,密码体制的整体效率大部分取决于GF(2m)上的运算效率。该文给出了有限域GF(2m)上使用正规基表示时的一种快速求逆方案,该方案基于基转换技术,更改运算元素的表示基,采用多项式基的AI求逆算法进行运算。实验表明,此方案比普通的正规基求逆算法更加快速。     

有限域GF(2m)模逆算法的改进与实现

在椭圆曲线密码体制中,有限域GF(2m)中模逆运算是最重要的运算之一。在分析一种通用有限域GF(2m)模逆算法的基础上,提出改进算法。改进算法减少了原算法快速实现时的缺点,能够有效地提高算法效率。基于FPGA分别实现了GF(283)和GF(2233)中模逆算法模块,并与2种已有实现结果进行了对比。结果表明,选取有限域GF(283)和GF(2233)时,改进算法效率提高率分别约为72.9%和59.5%。     

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。     

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。