基于扩展ARP协议的EPON+EoC+IPQAM网络寻址设计

针对EPON+ EoC+ IPQAM网络中,基于应用层协议交互下行QAM通道信息时,数据封装开销大、交互次数多的问题,设计一种基于扩展ARP协议的网络寻址方案.E-ARP采用TLV编码格式,在标准ARP协议中扩展EEQAM网络中调制解调和QAM通道的描述信息,并增加调制解调器和QAM通道交互过程,以实现EEQAM的网络寻址.数值分析证明E-ARP相比应用层的HTTP/XML、SOCEKT通讯,交互次数少,封装开销低,通讯效率更高,且具有良好的扩展性.     

ONU型网关融合接口的设计与实现

网关型ONU作为网关及PON技术的融合,不仅保持了PON原有的管理方式,还支持运营商实现远端管理;PON系统具有高带宽和低成本等优势;在ONU网关上开发融合无线接口,可以在支持传统有线业务的基础上,丰富光纤系统的接口种类;既保持原有优势,又增加系统的无线资源;传统的方法是在有线接入设备上开通无线接入通道,不能实现集中控制和管理;针对现有技术的不足,提出了新的设计方法,采用基于FPGA和嵌入式处理器的方法;进一步给出了详细的实现过程;测试验证表明该设计比原有方案有优势。     

一种基于现有网络提升带宽的方案

针对网络传输带宽的瓶颈限制,该文提出一种带宽改造方案,对现有网络进行改造,设计的依据是电话线传输上行链路信号,闭路电视传输下行链路信号。利用现有的网络既可以实现上网功能,又可保持原有电话线路和电视线路的功能,减少重新布线造成的资源浪费,对解决光纤入户的带宽瓶颈问题和今后的家庭智能化提供一种方式。该文改造方案可以增加带宽,提高传输速率。     

一种基于现有网络提升带宽的方案

针对网络传输带宽的瓶颈限制,该文提出一种带宽改造方案,对现有网络进行改造,设计的依据是电话线传输上行链路信号,闭路电视传输下行链路信号。利用现有的网络既可以实现上网功能,又可保持原有电话线路和电视线路的功能,减少重新布线造成的资源浪费,对解决光纤入户的带宽瓶颈问题和今后的家庭智能化提供一种方式。该文改造方案可以增加带宽,提高传输速率。     

基于博弈论的Multi-homing负载均衡

针对移动网络的多主接入中的负载均衡问题,提出一种基于博弈论的解决方案。通过建立效用函数,量化用户对带宽的需求,根据用户对网络带宽的需求建立Bertrand博弈模型,求解出用户需求带宽的Nash均衡价格,并利用Nash均衡价格调整带宽资源的分配,从而最大化网络自身收益。仿真结果证明算法是有效的,该方案能够合理有效地利用带宽资源,实现了负载均衡。     

带宽聚合扩展企业网络

当企业不断壮大时,你的网络用户数量也在不断增长,你会发现自己需要更多的带宽用于连接互联网,或更多专用线路带宽用于连接远程办公室。但你可能尚未有足够的实力和预算去升级到更高水准的线路,比如将原有的T1线路更换为T3线路。作为替代方案,通过使用带宽聚合技术,你可以购买多条低价线路并聚合它们从而得到所需的带宽,而且该方案可以在需求持续增长时不断地进行带宽扩展(并且是渐进的扩展)。带宽聚合如何工作带宽聚合技术的概念非常简单:简单聚合两条或更多连接的带宽,提供给单独一条连接使用。实现的办法有简单的,也有复杂的(甚至包括负…     

基于多层AHB架构的多核SoC设计

设计并实现一个基于多层AHB架构的多核异构片上系统。以ARM和DSP处理器为核心,对控制密集型任务和计算密集型任务进行合理分配并高效执行。采用分布式存储和共享存储相结合的存储器配置方案,保证数据完整性与程序并行性。利用基于多层AHB的开关矩阵结构,使不同主设备在不竞争同一个从设备时可并行访问总线。实验结果表明,该系统的资源消耗和延迟较小,可支持较大的网络带宽。     

一种基于效用最大最小公平性的QAM资源分配算法

介绍一种基于IPQAM的接入网下行带宽扩容系统,并针对该系统中的QAM资源分配问题展开研究.将业务的带宽需求描述为带宽上下限和效用函数,以UMM(Utility Max-min,效用最大最小)公平性为研究目标,设计了一种新的单链路UMM公平分配算法.该算法与基于分段线性函数的算法相比,具有更高的计算精确度,而时间复杂度相似.基于该算法,在兼顾带宽利用率和效用公平性的原则下,设计了QAM频点选择算法和单频点带宽分配算法.仿真结果表明,本文的单链路UMM公平分配算法具有较高的精确度,并且,QAM频点选择算法使得多频点间公平性较好.     

一种新的支持区分服务的动态队列管理方案

首先简述Intemet的服务质量保证能力的不足,分析了区分服务的网络系统模型和实现机制,然后提出一种边界结点采用基于TSW的三色标记算法和核心结点采用自适应RIO算法相结合的支持区分服务的路由队列调度和管理方案。最后对该方案的带宽资源使用效率进行分析,能够保证各个流聚集在共享带宽资源的公平性。     

EPON+EoC双向改造方案

目前在电信网、广播电视网和互联网三网逐步融合的背景下,有线电视网络面临前所未有的挑战.使用何种改造方案来实现双向网络的改造就显得尤为重要.介绍了广电网络双向改造的技术方案及其特点,对有线电视网络双向改造使用的CMTS+CM,EPON十LAN,EPON+Eo(;三种方案的优劣进行了分析和比较,对Eo(:技术进行了详细论述.从业务性能、建设成本、改造技术复杂程度等方面进行分析,最终认为EPON+EoC是广电网络双向改造、实现三网融合的最佳方案.广电网络运营商应根据实际情况,选择适合的EoC方案.     

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.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

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.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

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     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to 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     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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