MIPv6网络中一般注册的高效认证机制

为解决移动IPv6(MIPv6)网络通信一般注册中节点的身份认证问题,提出一种高效认证机制。改进基于身份的签名方案,使一般注册仅需往返2次就能完成消息交互,实现移动节点和通信节点之间的双向认证,同时生成双方通信的共享密钥,以保护之后的消息交互过程。分析结果表明,该机制具有高效性和安全性。     

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。     

移动IPv6网络安全接入认证方案

对于移动IPv6网络,身份认证是网络安全的关键问题之一.针对移动IPv6网络的接入认证,提出了一种基于移动互联网双向认证方案.在移动切换过程中的接入认证和家乡注册,采用对家乡注册消息进行基于双私钥签名的方式,实现了家乡代理和移动节点分别对注册消息的签名,实现了接入认证与家乡注册的并发执行,移动用户和接入网络的一次交互实现了用户和接入域的有效双向认证.理论分析和数据结果表明,方案的认证总延时和切换延时要优于传统方法,有效地降低了系统认证的延时.安全性分析表明,框架中的基于双私钥的CPK方案满足双向接入认证安全,有效地解决了密钥托管问题.     

移动IPv6网络层次化接入认证方法

对接入用户实施认证是移动IPv6实用化的前提.提出一种适用于移动IPv6网络环境的层次化接入认证方法HAMIPv6,对接入认证和移动注册进行层次化管理,利用认证矢量和消息捎带,减少切换认证过程中移动节点与家乡域的交互.HAMIPv6简化了切换认证处理流程,减小了切换延时和信令开销,实现了用户与网络相互认证及会话密钥发放.通过分析比较证明,HAMIPv6比传统方法处理效率更高,尤其是在MN远离家乡域及在一定范围内频繁微移动的情况下.     

节点证书与身份相结合的HMIPv6 网络接入认证机制

接入认证是层次型移动IPv6(HMIPv6)网络安全的基本需求.构建了适于HMIPv6的分层认证框架,设计了一种节点证书与身份相结合的签名方案,并以此为基础提出了HMIPv6网络双向接入认证机制.该机制利用基于身份密码技术简化了公钥基础设施的复杂密钥管理过程;以节点证书为接入认证的主要依据,消除了接入网络与家乡网络间的消息交互;采用提出的层次化签名方案,实现了用户与接入网络的双向认证.机制经过简单扩展,能够支持多层HMIPv6网络的接入认证.性能与安全性分析表明,与传统的及其他基于身份的认证方案比较,所提出的机制拥有更高的认证效率和安全性.     

移动IPv6网络基于身份的层次化接入认证机制

设计了一种基于身份的层次化签名方案,并在该方案基础上提出了一种适用于移动IPv6网络环境的层次化接入认证方法.该方法使用分级NAI(Network Access Identifier)作为公钥,简化了无线移动环境中的密钥管理;利用层次化思想对接入认证和移动注册进行层次化管理,减少了切换认证处理流程;基于签名机制实现了用户与接入网络的双向认证.作者用设计的切换延时分析模型,对该方法和几种传统方法进行了比较,证明当移动节点远离家乡域及在一定范围内频繁微移动时,该方法比传统方法的效率更高.通过安全性分析证明了该方法在一定程度上实现了私钥的保密性、签名的不可伪造性等功能.最后还讨论了该方法的一种可扩展变形,用于实现多级层次化移动IPv6框架下的接入认证.     

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PMIPv6的移动网络快速切换方案

针对移动网络应用在代理移动IPv6域中存在切换时延大并且缺乏对域间切换有效支持的问题,提出一种基于PMIPv6的移动网络快速切换方案。该方案通过结合二层机制在移动节点完成注册之前进行预切换,提前获取节点信息,建立缓存数据转发隧道,利用扩展的信令消息进行不同域间实体的交互,实现对域间切换的有效支持,并引入双重缓存机制,避免了切换过程中的分组丢失。分析和仿真结果表明,本方案相对传统机制,降低了系统切换时延。     

免重复地址检测移动IPv6快速切换方案

移动IPv6(MIPv6)的切换性能是保证移动互联网服务质量的重要因素之一。针对MIPv6中移动节点切换时延长的问题,提出一种免重复地址检测移动IPv6快速切换方案。该方案重新划分IPv6地址的64位接口标识符为1位移动标识位、32位家乡代理IPv4地址和31位随机数,可保证移动节点接口标识符在全网的唯一性,使移动节点在不同链路切换过程中不再需要重复地址检测,进而可有效提高移动节点的切换性能。仿真实验结果表明,该方案不需要进行任何重复地址检测即可完成移动节点无缝切换,且缩短移动节点切换时延约25%。     

结合信任机制的移动IPv6网络快速跨域认证方法

在移动IPv6(MIPv6)网络中,当移动用户从外地域接入网络时,家乡域和接入域需要协作实现对移动用户的身份认证,各管理域之间存在域问信任关系是域间协作实现用户身份认证的基础,现有MIPv6网络快速认证方法在实施域间认证的过程中忽略了域间信任关系,由于缺乏域问信任而造成的认证失败在整个认证流程结束以后才能被检测到,提出一种结合信任机制的MIPv6网络快速跨域认证方法,其中在预切换阶段考虑移动用户家乡域和接入域之问的信任关系,通过移动用户和接入网络的一次交互实现用户和接入域的有效双向认证,并设计了域间信任关系的动态维护机制,基于组合公钥(CPK)算法设计了网络实体的身份签名和验证方案,用于加速双向认证过程,理论分析和数值分析结果表明,提出的方案比现有方案在减少总认证切换延时和信令开销方面更有效,同时基于CPK算法的安全性,提出的方案在有效实现用户和网络的双向认证的同时可造性.     

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。     

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。