FPGA块存储器的多位翻转容错设计

在高可靠性航空航天、航空电子设备和军用应用中,辐射引发的多比特翻转(MBU)成为FPGA存储器的一个主要的可靠性问题;传统的单比特错误纠正(SEC)和双比特错误检测(DED)无法对FPGA存储器发生的MBU故障提供防护,引发存储器的存储故障;为了减少MBU造成的影响,设计了RM(2,5)编码防护系统对FPGA块存储器进行容错防护,实现了单个码字小于4位的翻转错误的纠正;对RM编码系统进行了三模冗余设计,解决了RM码不具备抗辐射的缺陷;设计的RM(2,5)编译码模块在Xilinx Virtex-5 FPGA中实现,编码模块频率以225.284 MHz运行,占用LUT资源1.33％;通过理论分析和硬件实验表明,该错误检测与纠正(EDAC)系统能够纠正4位以下的翻转,提高FPGA存储器的可靠性.     

一种基于FPGA的航空总线容错机制设计

航天应用中,单粒子翻转引发SRAM型FPGA的错误最多,而EDAC设计在纠错模块中有着广泛的应用。将依据扩展海明码设计的[40,32]EDAC模块嵌入到ARINC 659的双口数据DPRAM和指令SRAM中,提高了总线控制器的容错处理能力。     

基于单片SRAM的EDAC电路设计

在航天应用中,为了减少单粒子翻转效应的影响,星载计算机的RAM存储单元采用检错纠错(EDAC)设计。本文介绍了EDAC原理,并对EDAC电路组成进行改进,将数据和校验存储在一片64Kx8的SRAM中,通过FPGA内部逻辑实现EDAC功能和RAM读写控制,增加了纠错回写和纠错计数功能,并提供测试验证EDAC功能的方法。     

空间计算机存储单元容错性研究

近年来随着商业航天的发展,空间飞行器计算机系统开始大量使用工业级甚至商业级电子元器件,这种设计带来众多优点的同时却存在一个严重问题：商用芯片无法直接适应空间环境,商用元器件存储单元在空间环境下现单粒子多位翻转MBU（multiple bits upset）的情况越来越多,传统容错方法由于纠错能力不足无法解决此类问题,为解决上述不足文中提出了一种改进型准循环码作为容错方法来解决单粒子多位翻转问题。仿真和试验结果表明,该方法可以满足存储单元相邻位2位、3位翻转的纠错需求,且编码逻辑简洁,编解码延迟较低,适于工程应用。     

基于FPGA的星载计算机自检EDAC电路设计

为了消除空间环境中单粒子翻转(SEU)的影响,目前星载计算机中均对RAM存储单元采用检错纠错(EDAC)设计.随着FPGA在航天领域的广泛应用,FPCA已成为EDAC功能实现的最佳硬件手段.本文介绍了EDAC的编码和实现,提出一种功能完善的、具有自检、自纠错功能的EDAC电路设计,并采用仿真工具对该EDAC电路的功能进行了验证.     

空间粒子辐射引起存储单元多位比特纠错方案

介绍了汉明码检/纠错的原理,并以IDT公司开发的具有检测两位错误和纠正一位错误的IDT49C465检/纠错电路单元为基础,针对主存储器某地址单元遭遇高能粒子轰击导致两位或多位比特出错的情况,提出了解决这类错误的一种方案。此方案通过利用阵列移位寄存器组对存储区数据进行转置来实现,并对此方案的数据可靠性做了概率分析。     

空间粒子辐射引起存储单元多位比特纠错方案

介绍了汉明码检/纠错的原理,并以IDT公司开发的具有检测两位错误和纠正一位错误的IDT49C465检/纠错电路单元为基础.针对主存储器某地址单元遭遇高能粒子轰击导致两位或多位比特出错的情况,提出了解决这类错误的一种方案.此方案通过利用阵列移位寄存器组对存储区数据进行转置来实现,并对此方案的数据可靠性做了概率分析.     

基于低复杂度编译码的数据流错误纠错方法

针对单粒子翻转可能带来的数据流错误,设计一种改进的数据流错误纠错方法。利用线性分组码的相关理论,分析常用数据流容错方法的容错能力,从线性分组码的编译码原理出发给出一种低复杂度编译码算法,基于该编码的容错方法能够以较少的开销纠正单粒子翻转造成的单比特数据错误。实验结果表明,该方法能够有效纠正单粒子翻转造成的数据错误,与常用的纠检错方法相比,具有较优的纠错性能和较少的容错开销。     

基于32位SPARC微处理器的EDAC设计

EDAC（错误检测和纠正）是星载计算机对付单粒子事件有效的策略。本文给出了基于32位SPARC体系结构微处理器TSC695F的EDAC设计,并给出了采用错误注入方式对于该设计的测试,证明了设计是正确的。     

SRAM型FPGA SEU缓解与验证技术分析

SRAM型FPGA产品在空间应用中易受单粒子翻转(SEU)影响而产生系统失效。分析了FPGA器件SEU的故障模式,并结合工程实践对三模冗余(TMR)技术、纠错编码(EDAC)技术、配置刷新技术三类FPGA单粒子效应缓解措施和基于故障注入的验证手段进行了研究和比较分析,阐述了不同技术的适用范围和优缺点,给从事空间应用系统的设计和测试人员提供参考。     

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。     

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。