混合有状态和无状态地址自动配置的快速切换

移动IPv6允许移动节点在移动过程中保持与通信节点的正常通信,而无须改变其固有地址.但是,移动节点在切换过程中的时延不能够满足对服务质量要求比较高的应用程序,如VoIP等.如何提高移动节点的切换效率成为移动IPv6应用的关键.文中介绍了IPv6有状态和无状态地址自动配置机制、移动IPv6的切换过程,分析了移动IPv6切换的时延问题.提出了混合有状态和无状态地址自动配置机制的快速切换,并详细说明了其原理.混合机制相比移动IPv6中单独使用无状态地址自动配置机制能够明显降低地址重建的时延,提高移动IPv6的切换性能.     

DIAMETER移动IPv6应用扩展方案

该文在DIAM ETER移动IPv6应用扩展基本模型的基础上,针对IPv6的无状态和DH CP有状态两种地址自动配置方式,分别在接入路由器和DH CP服务器上进行AAA功能扩展,给出了相应的DIAM ETER移动IPv6应用扩展方案。之后提出一个将两种地址自动分配方式结合使用的DIAM ETER移动IPv6 AAA解决方案,既可以减少移动节点跨域移动的时延,又便于网络资源的统一分配。文章最后给出了已实现的无状态地址分配方式下DIAM ETER移动IPv6AAA系统的实验结果,从而证明了所提方案的有效性。     

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%。     

基于MIPv6的有状态地址配置的设计与实现

MIPv6中转交地址的配置直接影响移动IP的切换性能,通常采用无状态地址自动配置,在实际应用中难以有效管理且安全性较差.针对这一问题,本文在RFC3775协议设计的基础上,分析比较了集中式和分布式有状态地址配置(DHCPv6)部署方法优缺点,设计并实现了移动lP有状态地址配置转交地址方案,并给出了实验结果.结果表明有状态地址配置方案能够有效实现对移动节点管理,满足实际应用的需要.     

基于一种新的移动锚点选择算法的分层移动IPv6策略

针对在分层移动IPv6(HMIPv6)中域内切换和域间切换的时延相差较大的问题,提出一种新的移动锚点(MAP)选择算法。在域内切换时继续使用HMIPv6,在域间切换时则采用一种基于预重复地址检测(DAD)的HMIPv6(D-HMIPv6)机制。D-HMIPv6通过引入一个同伴节点(PN),进而帮助移动节点(MN)在域间切换时预先完成部分3层切换,以此来减少重复地址检测过程所带来的切换时延。网络仿真工具NS-2的结果表明,相比HMIPv6,D-HMIPv6把域间切换过程中的时延缩短了将近2s,有效地提高了对移动IPv6实时应用的支持能力。     

移动IPv6环境下的QoS机制研究

移动IPv6为IPv6节点提供了在Internet不同子网中使用不变的家乡地址进行漫游通信的能力。相比于传统固定网络，节点的移动为通信的服务质量（QoS）保证提出了新的挑战。介绍了当前的移动IPv6技术和IP网的QoS技术，并针对移动IPv6的特点阐述了其QoS机制，对比各种机制的特点，对其进行网络时延的分析。最后说明了移动IPv6的QoS需要解决的问题。     

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。     

APHMIPv6：快速移动IPv6切换算法

当移动节点发生切换时,其切换时延和丢包率问题将严重影响实时业务的应用。针对这一问题,该文进行了理论分析并提出了一种基于地址池的层次型移动IPv6切换算法（APHMIPv6）。该算法与层次型模型相结合,采用基于地址池的有状态地址配置策略以及域间切换时利用隧道机制来提高切换性能。仿真结果表明,该算法能有效地减少移动节点切换时延和丢包率,尤其在域间切换时,性能更加显著。     

移动IPv6切换技术研究

由移动IPv4技术发展而来的移动IPv6技术应用前景可观,但其存在诸多问题,如移动节点在不同网络间移动带来的网络切换问题,切换过程中地址重复检测的延迟问题等.基于层次化的移动IPv6,详细阐述了目前移动IPv6的几种切换技术,并对现有的几种切换技术在切换时延方面进行了比较,发现层次型快速切换技术有更小的切换时延和丢包率.     

APHMIPv6:快速移动IPv6切换算法

当移动节点发生切换时,其切换时延和丢包率问题将严重影响实时业务的应用.针对这一问题,该文进行了理论分析并提出了一种基于地址池的层次型移动IPv6切换算法(APHMIPv6).该算法与层次型模型相结合,采用基于地址池的有状态地址配置策略以及域间切换时利用隧道机制来提高切换性能.仿真结果表明,该算法能有效地减少移动节点切换时延和丢包率,尤其在域间切换时,性能更加显著.     

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。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

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AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.     

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.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

Call for papers Special issue on Modeling and control technologies for civil,energy,and power systems

正The control of civil,energy,and power systems presents significant new challenges for modeling and control theory.The purpose of this special issue is to provide a forum for researchers and practical engineers to discuss the recent advances in modeling and control technology development for civil,energy,and power systems.Prospective authors are invited to submit their original contributions with the focus on theory or applications of modeling,control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate and promote academic exchange between Chinese and foreign scientists everywhere.