NoC中基于路径多样性的交叉开关细粒度容错设计

在片上网络中,交叉开关是路由器的重要组成部分,当其出现故障会导致数据无法传到下一跳,易造成资源浪费,影响整个网络的性能.对此,通过详细考虑交叉开关中数据分配器、内部链路以及数据选择器的故障情况,充分利用交叉开关的可用资源,提出交叉开关细粒度容错设计方案,实现容错路径的多样性.当数据到达数据分配器时,查看故障信息表,若存在故障则顺序选择一个无故障的数据分配器传输数据;当数据经过数据分配器传至内部链路时,若存在链路故障,同样查找故障信息表快速选择合适的容错链路进行传输;最后数据到达数据选择器,若此时数据选择器出现故障,数据则经过额外的数据选择器到达输出端口.实验结果表明,故障率逐渐增大的时候,该方案比已有方法平均延时降低了6%~36%,吞吐率提高了6.7%~27.7%,且容错效果不会随着故障率增大而显著下降.     

一种新的容错ATM交换机结构的冗余路径分析

异步传输模式ATM是国际化电信联盟建议用于宽带综合业务数字网（B－ISDN）的传输模式。容错是提高网络可靠性的主要方法。该文讨论了一种新的容错ATM交换机结构。该结构以Banyan交换机结构为基础,通过增加子交换单元和扩展链路来增加冗余路径的数目,该结构可以容错多个故障,并且冗余路径的数目随着交换机级数的增加而指数增长。同现有文献中其它容错ATM交换机对比分析可以看出,在具有相近的交换元素个数的前提下,建议的交换机提供了更高的容错能力。     

基于动态优先级的3D NoC偏转路由容错方法

若3DNoC中水平和垂直方向出现不可恢复的链路故障,将严重影响整个网络的性能.为此提出一种新型的高效率、低开销的容错方法——基于动态优先级的偏转路由方法.该方法根据目的节点和当前节点的相对位置,动态地设定输出端口优先级,以确保数据包始终选择最优路径传输;为了提高层内和层间数据包传输的速度,采用了两级交叉开关结构.使用Booksim 2.0和Orion 2.0工具与其他方法的实验结果表明,文中方法的网络平均包延时最大降幅达20%,且面积不随网络规模增大而增加,提高了片上网络整体性能.     

一种高可靠可控双冗余以太网的设计与实现

提出了一种高可靠可控双冗余以太网架构方案,其通过在两个网卡上发送内容相同的数据包,防止出现网络丢包时的信息丢失。在以太网的用户数据头部添加帧冗余标签用于标识冗余和非冗余数据以及区别冗余数据的不同帧,当网络出现故障时,可以达到零故障恢复时间。引入网络诊断功能,通过节点间的软件收发和处理诊断相关的UDP报文来判断网络是否出现故障,并及时记录。通过Winsock SPI和API实现网络的冗余通信和诊断功能,以保持对应用层网络程序透明,同时又保证网络的高可靠性和可用性。实验表明,在局域网内可以容忍多个不同节点到交换机的故障,增加网络发送的数据量,以实现较高的容错率。     

飞行管理计算机总线数据采集系统设计与可靠性优化

为了满足某型飞机对飞行管理计算机数据的采集需求,基于FPGA设计了DFTI(数字飞控传输接口)总线数据采集方案,在复杂电磁环境下,当输入数据被干扰、数据格式被破坏时,接口逻辑出现混乱,可靠性分析发现标准总线接口协议信号适应性较差.针对此问题,对解码、接收控制过程及接收缓存进行了设计优化,通过改进同步判断流程,增加容错机制,优化缓存宏模块等措施,提高了系统可靠性,试验验证表明可靠性优化设计合理可行.     

高可靠性智能容错网络设计与实现

普通容错网络存在初始启动时间长、切换延时大、部分故障无法处理等缺点,导致可靠性降低;利用设备冗余原理,提出一种高可靠性智能容错网络设计方案,设计了智能双冗余交换机和双冗余网卡及相关驱动软件;结果表明此方案可成功实现网络冗余切换,有效缩短初始启动时间和切换延时并能处理绝大部分故障,提高通信网络的可靠性;本容错网络方案已应用于某军用系统。     

马尔科夫决策过程在多路径冗余传输调度算法中的应用

传统网络终端设备通常以单路径连接网络,因此在路径发生异常时通常严重影响数据传输质量.随着重叠网络和异构多接入网络的发展,多路径传输逐渐成为可能.多路径传输中数据发送端的多路径调度算法是研究多路径传输的核心问题.本文提出了一种基于马尔科夫决策过程的多路径冗余传输调度算法,通过分阶段采用稳态马尔科夫策略并对关键数据进行冗余传输,实现了实时性要求较高的数据传输,提高了数据传输可靠性.仿真实验表明当路径传输质量发生改变时,该调度算法能够正确感知并将数据更多的调度到传输质量较好的路径上,有效降低路径质量变差时对传输的影响.该算法可应用于音、视频等实时业务中,能够有效提高用户使用体验.     

互联网络拓扑结构Cayley图可靠性容错延迟的研究

互联网的可靠性是评估一个网络性能的重要指标,而影响网络可靠性的因素又有很多其中容错性可以验证一个网络在发生故障时剩余网络的重组能力的强弱.在一个容错网络中当网络的结点和(或)连线发生故障时,使数据能畅通有效的传输且延迟时间尽可能短,这就需要有一个设计很好的路由选择ρ.而度量路由选择优劣的重要参数容错延迟的确定显得很重要,本文就证明了某些Cayley图存在路由选择使它的容错延迟能够达到最小值.     

一种基于多路径的传感器网络安全数据传输机制

本文针对传感器网络提出了一种基于多路径的安全数据传输方案,通过在多条路径上分发数据,达到增强机密性和鲁棒性的目的。针对数据机密性,设计基于异或计算的编码方式,使得攻击者解析任何数据片段的难度等同于攻占所有的K条路径。针对传输的鲁棒性,设计了数据分发算法以及备份与校验相结合的容错模式,实现了容忍多条路径失效的数据传输,并且具有适度的数据冗余、理想的路径利用率以及快速的数据恢复能力。     

MPE2S: 基于多路径纠删编码的无线传感器网络可靠传输策略

传输可靠性是衡量无线传感器(Wireless sensor networks, WSN)网络性能的一个重要指标. 针对节点故障会影响网络传输稳定性和可靠性的问题, 提出了基于多路径纠删编码的 无线传感器网络可靠传输策略(Multi-paths and erasure encoding strategy, MPE2S). 根据反映链路质量的最优最差蚂蚁系统的信息素归一化值, 在相邻等级节点间建立多条互不交叉的传输路径, 将源数据包经纠删编码的 数据片沿多条路径分配和传输以实现负载均衡和故障容错. 理论分析和仿真结果表明,MPE2S具有较高数据包接收率、数据准确率和能效性, 体现了良好的故障容错性、数据传输稳定性和可靠性.     

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.