不只是扩展带宽——万兆更需关注业务与性能

万兆代表着未来发展的方向,从2003年年底至今,国内外网络设备提供商相继推出了万兆交换机产品。但用户在享受到足够带宽的同时,也对处理每个分组业务的高服务质量QoS保障提出了更高的要求。作为率先为用户提供端到端的万兆解决方案的极进网络,在将万兆向边缘拓展的同时,还为用户构建万兆网提供了包括带宽管理、业务整形和业务分类的基于策略的以太网QoS功能。在为用户扩展带宽的同时,更关注到了用户网络的业务和性能。智能带宽管理极进网络基于策略的QoS可消除在广域网和VLAN扩展到远距离时出现的时延相关误差,保证了精确控制每条分组流…     

实现高宽带应用

思科公司针对企业和服务供应商的带宽需求研制了新型10千兆以太网模块,帮助用户更好地利用城域网。     

支持动态带宽分配的呼叫接入策略

为了适应无线网络对多媒体业务的业务服务质量的需求,论文根据无线网络的多媒体业务特征,提出了一种支持动态带宽分配的无线多媒体业务的呼叫接入策略。通过对该策略进行数学模型分析和数值仿真,结果表明,该策略在小区带宽紧张时,通过降低可变带宽业务的业务带宽,能有效降低用户呼叫阻塞概率和中断概率;在小区带宽有剩余时,可以通过增加可变带宽业务的服务带宽来提高资源利用率。另外,可变带宽业务还能够灵活地借用为越区切换用户预留的带宽资源,充分地利用系统资源。     

以太网带宽管理机制下TCP性能的建模研究

随着以太网技术的迅速发展,基于以太网的链路层流量控制技术成为流量工程的一个重要组成部分,基于漏桶式流控的以太网带宽控制算法被应用于驻地同环境当中。考虑到互联同中长时TCP业务流量增长迅速这一背景,评估以太网流量控制算法对长时TCP性能的影响有其积极意义。论文通过建模分析的方法,对于NewReno TCP算法在漏桶式带宽控制机制下的性能进行了分析,并通过仿真对结论进行了说明。     

改进的WiMAX上行链路调度机制

基于IEEE 802.16e协议的实时业务调度机制,以及对VoIP业务特性的分析,提出了一种改进的上行链路调度机制,该调度机制自适应地调整数据带宽分配周期。从理论上分析了所提出的调度机制和已有调度机制的VoIP用户容量。系统仿真结果表明,在保证系统容量的前提下,所提出的调度机制可以有效地降低用户的上行时延,从而提高了服务质量。     

基于工业以太网的列车通信网络及其仿真研究

随着列车运行速度的提高,新型大容量业务不断出现,带宽已成为列车通信网络传输的主要瓶颈;根据列车通信网络的发展趋势,对未来工业以太网用于列车通信网络的两种可能形式进行了探讨,提出了基于工业以太网的列车通信网络体系结构,利用网络仿真软件对列车通信网络进行了拓扑结构建模、节点建模和进程建模.利用该模型研究了车载工业以太网传输大容量信息传输过程中网络载荷、以太网时延和端到端时延等关键因素;仿真结果表明,通过合理设置网络参数,工业以太网满足列车通信网络的带宽和传输要求,环形网络在中间出现故障情况下,仍然可以保证正常的网络通信.     

升级到万兆

以太网的发展经历了从10Mbps、100Mbps 1Gbps到10Gbps(万兆以太网)的发展过程。目前,万兆以太网已经走出了象牙塔,进入了实际应用阶段。万兆以太网可以满足新的容量需求,解决低带宽接入,高带宽传输的瓶颈问题,能扩大应用范围,并涵盖和兼容以前的几类以太网技术。对于用户来说,万     

以太网无源光网络中的QoS研究

在分析以太网无源光网络系统MAC协议的基础上,研究基于QoS的动态带宽分配机制,提出一种新的支持业务的QoS的动态带宽分配算法。该算法采用限制性带宽分配方法和基于优先级的调度方式,基于业务的通信量特征对各类业务预分配传输带宽。仿真结果表明该算法在时延和吞吐量性能上优于现有算法。     

基于FC-AE-ASM的IP业务传输方法的设计实现

随着FC-AE网络在高可靠性网络中的应用越来越广泛,在FC-AE网络上传输IP业务不仅拓宽了FC-AE网络的应用范围,而且能够实现FC-AE网络与以太网网络的融合.提出了基于FC-AE-ASM协议的IP业务传输方案,在支持FC-AE-ASM协议的HBA卡物理设备上,构建了一个虚拟网卡内核模块.本方案扩展了TCP/IP协议栈,在网络接入层下扩展了一个FC接口层,实现了FC-AE-ASM帧对以太网帧的封装和解封装.同时,利用FC网络底层流控机制,实现了IP业务在FC-AE网络上的高可靠性传输.通过实验组网测试可知,本方案在延时、带宽、抖动、丢包率等方面相对于商用千兆网卡都有较多的优势,在航空航天等应用场景具有重要的应用价值.     

基于边缘计算的多用户动态带宽分配方法

当前多个集群框架布置在同一个数据中心增加了动态带宽的分配时间。针对这种情况,提出一种基于边缘计算的多用户动态带宽分配方法。该方法采用循环神经网络计算构建分配模型,并通过3层分配机制和边缘框架进行带宽的弹性共享应用。用户业务的优先流转级别通过共享机制设定,促进多用户的业务需求同步传输,同时实现多用户动态带宽的分配。实验结果表明,该新方法可以基于不同的用户规模进行分类,具有高效的分配效率和实用性。     

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。     

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.     

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.     

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。     

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.     

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。     

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     

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.