用标记交换技术 改进Internet核心

集成路由和交换在Cisco提供可扩展的Internet解决方案的整体战略中,重要的内容是将第三层(网络层)的路由功能与第二层(数据链路层)的交换功能集成在一起。标记交换技术为服务提供商提供三种重要优势: 可扩展性:标记交换技术集成了ATM与第三层的路由,扩展了网络功能。标记交换技术提供了ATM交换功能,全面地集成于Internet核心网络中,包括BGP路由协议,而且避免了单纯在第二层网络上设置路由器所带来的扩展性问     

LANNET详解多层交换

什么是多层交换技术?多层交换技术与路由器的区别是什么?为了给广大用户详细介绍多层交换技术的各个方面,LANNET 公司于本月在北京、昆明、南京、广州和成都举办关于多层交换技术的巡回研讨会。一个多层交换机从逻辑上可以被看成一个附带有一个第三层转发功能的第二层交换设备,同时它与第三层的数据转发模块采用高速互联。     

基于IXP2400网络处理器的第四层交换式负载分担系统设计

在深入分析基于第四层交换的负载分担技术基础上,利用Intel IXP2400网络处理器高度灵活的可编程性和强大的网络数据包处理功能,设计了一套具有第四层包交换能力的负载分担系统。该系统在二层交换模块上,添加第四层交换式负载分担模块,并应用了“一次处理,多次交换”的第四层交换技术思想,大大加快了系统处理速率。同时基于网络处理器的技术优势,使得负载分担系统具有良好的可扩展性和实用性。     

第三层交换问题探讨

介绍了第三层交换和第三层交换机的产生、特点、功能和技术,探讨了MPOA和MPLS两种第三层交换方案的机制和特性,并进行了对比分析。     

多层交换技术

本文从交换技术和路由技术谈起，简单地介绍了第三层交换技术的原理和目前主要使用的第三层交换技术；随后介绍了第四层交换技术的基本原理和作用，还介绍了第四层交换技术和服务器集群技术的联系。     

基于第三层交换VLAN技术网络应用——厦门职工大学二期校园网构建

本文通过对厦门职工大学校园网二期工程网络规划与管理为背景,详细讨论了基于第三层交换的校园网主干网络拓扑结构,VLAN规划策略与实现,说明采用三层交换技术,实现VLAN划分、高效的组播控制、流策略的管理和访问控制等功能,是有效保证网络资源充分利用。是建设高水平网络平台的重要技术措施。指出了交换技术在校园网络中的重要作用,论证了在校园网络中第三层交换技术的应用是实现简单的网络发展和扩充,提供高性能、高可靠性网络的最优方案。     

发展中的交换技术

交换技术背景知识 要了解交换技术,就必须先对“开放系统互连参考模型(OSI/RM)”有比较清楚的认识,它是国际标准网络体系结构,是一个七层模型。该模型包括七层功能及其对应的协议,每层完成一个明确定义的功能集合,并按协议相互通信。每层向上层提供所需服务,同时为了完成本层协议也要使用下层提供的服务。七个层次由下向上依次是:物理层、数据链路层、网络层、传送层、会话层、表示层与应用层。目前的交换技术的应用平台就是数据链路层(第二层)、网络层(第三层)和传送层(第四层)。下面就对这三层的相关知识作简要介绍:     

三层交换技术的原理及应用

本文在分析比较二、三层交换技术的基础上介绍了三层交换技术的工作原理。从网络扩展能力、数据处理能力、多协议支持能力以及冗余通道等多方面阐述了三层交换技术的特点。对比分析了基于硬件结构和基于软件结构的两种三层交换技术的工作流程,阐述了三层交换技术在虚拟局域网中的应用。     

基于三层交换的校园网设计与建设

对民办高校的校园网络进行相关研究后,从传统的交换与路由入手,介绍了传统的二层交换技术和路由技术与现代三层交换技术的区别,结合SDYC学院的校园网建设介绍了三层交换技术在现代校园网建设中的应用方法。     

计算机多层交换技术应用分析

对基于三层交换技术实现的局域网信息安全问题进行了分析探讨,在简单分析了三层交换技术的实现原理及实现方法的基础上,以校园网为例进行了三层交换技术的实际设计应用研究,给出了校园网的三层网络架构设计方案,并从硬件设备的链接和软件IP的配置两个角度完成了对基于第三层交换技术实现的局域网信息安全构建,对于进一步提高多层交换技术的应用及保障局域网信息网络安全水平具有一定借鉴意义。     

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.