基于路由信息缓存的快速移动IPv6切换方案

为了提升移动IPv6快速切换(FMIPv6)的性能,在研究FMIPv6协议的基础上,提出一种基于路由器信息缓存的快速切换方案。该方案中,移动节点通过建立和更新路由器信息缓存表,存储其运动中访问的路由器历史记录,从而减少移动节点进行转交地址配置和重复地址检测的延迟。仿真结果表明,该方案中移动节点在重复访问历史路由器时,能有效缩短切换时延,减少切换过程中的数据分组的丢失率。     

基于标准移动IPv6的新型无缝切换模型的研究

在利用移动IPv6协议进行节点的移动性管理过程中,切换问题是影响管理性能的最关键因素之一.为了提高移动网络服务质量,需对移动IPv6切换性能进行优化.针对标准移动IPv6(MIPv6)的切换技术的种种弊端,在深入分析其切换时延的基础上,提出了一种新型MIPv6无缝切换模型--双接口移动终端辅助切换.新方案的特点是在一张网卡上集成两个无线模块,利用双链路将移动节点在不同子网间的切换转变为移动节点内部接口的切换,基本上实现了无缝切换.而硬件的成本正在不断降低,显然通过低廉的硬件冗余来换取高质量的移动网络服务是完全值得的.     

移动IPv6中基于MLD的快速重复地址检测

移动IPv6尤其是层次化移动IPv6技术中，地址重复检测过程严重影响了移动节点的切换速度。这篇论文通过从搭建的层次化移动IPv6实验床收集的数据，分析了造成上述性能下降的原因，并据此提出了基于多播侦听者发现机制的快速重复地址检测方案，最后论证了此方案相对于传统方案的性能优势。     

层次移动IPv6宏切换的优化方案

针对层次移动IPv6宏切换中丢包率高、切换延迟大的问题,提出一种将隧道机制应用于层次移动IPv6的优化方案（TBFMH）。TBFMH根据切换信息提前获得转交地址,进行重复地址检测,并在建立隧道的同时完成本地绑定更新。仿真实验表明,TBFMH比层次移动IPv6至少减少50%的切换延迟,同时降低了丢包率,有效提高了移动节点进行宏切换的性能。     

一种混合移动自组网的地址自动配置策略

针对多种移动网络中动态移动和快速切换的要求,本文提出了一种新的Kinship二叉树以及根据该二叉树实现的IPv6混合移动自组网地址配置策略。本文对标准IPv6地址结构进行了扩展,讨论了节点的地址初始化过程以及网络的合并与拆分操作,最后对该策略的性能进行了分析。该地址配置策略能在多种移动网络中为移动设备快速配置唯一地址,而不需要执行重复地址检测过程(DAD),具有很低的开销。     

基于邻居信息表的移动IPv6切换研究

分析标准移动IPv6(MIPv6)的快速切换机制,提出一种基于邻居信息表的移动IPv6快速切换解决方案。通过预配置和定时更新的方法使移动节点提前获取将要进入目标有限区域的信息表——邻居信息表,从而缩短切换中过程转交地址唯一性验证时间及移动检测延迟时间,降低切换过程中的丢包率。仿真结果表明,该机制不额外占用网络资源,能够减少切换过程中的丢包率和切换延迟时间。     

MIPv6 AAA系统中绑定更新的设计与实现*

Diameter MIPv6扩展模型改变了MIPv6家乡代理绑定更新流程,移动节点在完成认证和授权的同时完成MIPv6家乡代理绑定更新,这样可缩短移动切换时延.为实现上述过程,提出了一种在Linux下利用Netfilter框架和Netlink套接字的Diameter移动IPv6 AAA系统中移动IPv6家乡代理绑定更新解决方案,并给出了方案的详细实现.     

基于层次化管理的流透明移动IPv6 QoS解决方案

针对目前移动IPv6环境下的IntServ／RSVP模型在处理移动节点切按时的不足，本文提出了一种基于层次化移动管理的流透明移动IPv6 QoS模型，简称为HMMFT移动IPv6 QoS模型。这种模型显著地减少了移动节点发给通信节点与家乡代理的绑定更新消息，提高了MIPv6的切换速度，同时基于移动节点的区域转交地址来标识流，实现了域内切换的流透明。本文的最后利用NS2对HMMFT移动IPv6 OoS模型性能的优越性进行了仿真分析。     

重复地址检测的MIPv6网络切换方法

为减小MIPv6网络切换时延,保证实时性要求高的语音、视频等业务的服务质量,针对MIPv6网络中,DAD操作时延严重影响网络切换性能的问题,提出一种减少DAD操作时延的方法。该方法将PIM和MLD协议用于FHMIPv6,并分别对微移动和宏移动中组播组的创建方法进行改进,利用仿真软件NS-2进行实验。实验结果表明,改进的方法减少了重复地址检测时延,降低了丢包率,提高了MIPv6网络切换性能。     

MIPv6快速层次化切换的高效认证机制研究

针对移动IPv6（MIPv6）层次化切换中各节点之间的身份认证问题,提出一种新的基于MIPv6快速层次化切换的认证机制。利用改进的IBS签名方案和层次化的网络结构,从域间切换和域内切换两个角度分别论述了移动节点和新访问域之间的双向认证和切换性能的问题。分析结果表明基于MIPv6快速层次化切换的认证机制效率高,安全性好,仅需来回一次消息交互就能实现切换与接入认证和绑定更新的同步。     

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.