Dijkstra最短路径算法

随着现场可编程门阵列(Field Programmable Gate Array,FPGA)技术的不断发展,FPGA以其研发周期短、研发成本低等优势,正在许多应用领域逐步替代ASIC产品.随着FPGA阵列规模的扩大和应用领域的广泛,其配套软件的布局布线算法对于改善FPGA性能的重要性越来越显著.对FPGA布线算法进行了深入的研究,介绍了迷宫矩阵的建立、改进的Dijkstra迷宫探索算法,实现基于布通率、最短路径、时序约束等各种布线要求的目的,使其更有效的提高了FPGA的性能.     

基于SRAM结构的FPGA抗辐射布局算法

分析由辐射造成的单粒子翻转(SEU)软错误,在通用布局布线工具的基础上,提出一种基于SRAM结构的现场可编程门阵列 (FPGA)抗辐射布局算法。该算法通过优化电路单元在FPGA中的布局位置,减少布线资源开路敏感错误、短路敏感错误以及SEU敏感点的数目。测试结果表明,该算法能减少SEU软错误,提高FPGA的抗辐射性能,并且无需增加额外的设计成本和硬件开销。     

基于整数规划的层次式FPGA布线算法

为了避免由于布线线序处理不当而导致无法布通的问题,提出一种基于整数规划的层次式FPGA布线算法.该算法使用一种全局优化处理的方式对布线问题进行求解,通过分析层次式FPGA的结构特点和整数规划的算法特点,导出了FPGA布线算法问题与整数规划之间的关系;然后具体描述了如何将FPGA布线问题转化成二进制整数规划问题及其相应的求解过程,其中利用层次式FPGA的结构特点对得到的整数规划问题进行简化.与可满足性布线算法进行实验比较的结果表明,文中算法具有求解速度更快、求解规模更大以及求解质量更高等方面的优势.     

基于FPGA的开方运算实现

开方运算作为数字信号处理(DSP)领域内的一种基本运算,其基于现场可编程门列阵(FPGA)的工程实现具有较高的难度.本文分析比较了实现开方运算的牛顿-莱福森算法、逐次逼近算法、非冗余开方算法3种算法,并给出了基于FPGA的开方器的实现方法,同时对逐次逼近算法、非冗余开方算法和IP_core的性价比进行了分析比较.     

基于FPGA的永磁同步电机转子位置的估算

设计了一种永磁同步电机(PMSM)转子位置估算的算法及数字电路实现方案,并给出了硬件描述语言VHDL的描述,最后在可编程逻辑器件FPGA上完成了布局布线和时序验证.实验结果表明能够获得较高的位置精度.     

反熔丝FPGA布线算法研究

国内外学术界对目前广泛采用的SRAM型FPGA布线算法均有大量研究,对于特殊用途反熔丝FPGA的研究却很少。首先介绍了反熔丝FPGA及其布线算法的研究现状,接着讨论了目前最为流行的FPGA布线算法——路径搜索算法的基本原理与实现方式,并且建立了反熔丝延时模型,然后针对反熔丝FPGA的结构对布线算法进行了改进,最后在CAD实验平台上实现了该改进算法。实验表明,该改进算法可以提高反熔丝FPGA布线的效率及电路速度。     

基于VPR的FPGA布局算法时延改进

基于模拟退火的现场可编程门阵列(FPGA)布局算法在计算关键度时存在一定的偏差。为此,提出一种FPGA布局时延改进算法。利用不同的模拟退火温度和交换接收率,以及前后2次布局的时延代价差,对FPGA布局的时延代价进行补偿。通过增加时延补偿模块来调整布局的代价函数,达到重新寻找布局过程中被遗弃的较优解的目的。实验结果表明,在MCNC基准电路上使用改进算法,布局的时延代价和线网代价分别比改进前的算法减少19.2%和0.5%。此外,电路的关键路径时延也得到了不同程度的改善,使得布局质量在各个方面都明显优于优化前的通用布局布线算法。     

基于FPGA的图像边缘检测Sobel算法的研究与实现

图像边缘是图像识别信息最集中的地方,Sobel算法是基于一阶导数的边缘检测,通过逼近导数来找到边缘。FPGA(Field Programmable Gate Array)即现场可编程门列阵,是在可编程逻辑器件(Programmable Logic Device)基础上发展的一种产物。该文即是采用FPGA技术实现基于Sobel算子的边缘检测算法。     

FPGA并行时序驱动布局算法

传统的基于模拟退火的现场可编程门阵列(FPGA)时序驱动布局算法在时延代价的计算上存在一定误差,已有的时序优化算法能够改善布局质量,但增加了时耗。针对上述问题,提出一种基于事务内存(TM)的并行FPGA时序布局算法TM_DCP。将退火过程分发至多线程执行,利用TM机制保证共享内存访问的合法性,并将改进的时序优化算法嵌入到事务中并发执行。测试结果表明,与通用布局布线工具相比,8线程下的TM_DCP算法在总线长仅有轻微增加的情况下,关键路径时延平均降低了4.2%,同时获得了1.7倍的加速,且其执行速度随线程数的增加具有较好的可扩展性。     

一种基于迷宫算法的有效FPGA布线方法

在本篇论文中,我们介绍了在标准对称阵列（隔离岛状）现场可编程逻辑阵列结构下的一种基于迷宫布线算法的新型有效布线方法,Pathfinder.实验结果显示,相比普通的迷宫布线法,Pathfinder算法在布线时间上减少了90%.     

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.