方格拓扑无线传感器网络源路由策略的能耗分析

无线传感器网络(WSNs)中的汇聚传输模式使得靠近汇点的节点承担了较多的数据转发业务,导致这些节点能量很快耗尽,降低网络的寿命。针对这种问题,结合规则拓扑结构的对称性和预知性,对方格拓扑结构中多种典型源路由策略进行分析,分别计算各策略的瓶颈节点负载和数据传输时延,提出能耗的计算模型,并据此探讨网络节点的通信能耗、待机能耗和总能耗。数值分析结果表明:均衡转发策略产生最小的总能耗。     

云基础设施中TPL2-SW网络模型的优化

为解决传统树型网络拓扑对大规模云集群造成的性能瓶颈,针对一种新的网络模型TPL 2-SW进行优化,提出了多路径负载均衡路由策略(MCLBR)和转发路由的硬件加速方案。通过在节点间建立网状链路,将负载指数纳入路由判定因素,并允许节点间负载分流;同时基于FPGA实现硬件转发路由器,并验证了在二层语义对多跳传输加速的可行性。仿真实验证明,优化方案可以在TPL 2-SW基础上显著提高网络的吞吐量和传输效率。     

一种适用于煤矿井下无线传感网的能量均衡路由协议

矿井无线传感网的拓扑呈长距离带状,节点间能耗不均问题十分严重。非均匀分簇策略能从全局均衡节点能量负载,在矿井中具有良好的适用性。针对矿井传感网的带状特性提出了一个簇规模自适应调节的能量均衡分簇路由协议。协议根据节点离汇聚点的距离、剩余能量及分布密度来构造规模不等的簇。簇首的竞选以节点相对于周围候选者的能量水平为依据,避免了低能量节点被当选为簇首。簇间多跳路由算法依簇首近似线型的分布特点设计,不但考虑链路能耗最优,亦注重转发节点间的能量均衡。模拟实验结果表明,该路由协议显著平衡了网中节点能耗,延长了网络生存时间。     

基于全局均衡策略的无线传感器网络路由算法

针对无线传感器网络的能耗均衡问题,提出了一种基于全局均衡策略的路由算法。该算法一方面利用基于区域划分的非均匀分簇方法均衡WSN数据收集汇聚树纵向上簇头之间的能耗;另一方面应用基于能耗与剩余能量复合权值的Dijkstra算法优化簇间路由——降低传输能耗并分摊数据转发任务,以均衡汇聚树横向上簇头之间的能耗。仿真实验结果表明,该路由算法能够有效地均衡网络中节点的能耗,显著延长网络的生存期。     

一种改进的多路径路由探测算法

随着网络中部分路由器使用了负载均衡策略,发往同一目的端的数据包不再沿着单一路由转发,传统的拓扑测量工具Traceroute将难以发现网络中的负载均衡链路及节点,测量精度受到影响。多路径路由探测算法（MDA）在端到端网络拓扑测量中能够有效地发现负载均衡节点产生的多条路径,但探测量却是Traceroute的近10倍。提出一种改进的多路径路由探测算法,通过设置全局查找表,源主机能够自适应地选择探测策略以及发送探测数据包的数目,保证了较高的测量精度,同时明显减少冗余探测。实验结果表明,改进后的算法能够发现网络中90%以上的IP中间节点,准确地反映了网络拓扑结构,但相比于传统的MDA路由探测算法,探测量减少了将近一半。     

双向路径重选的自组网负载均衡路由协议

基于跨层负载感知和双向路径重选的自纽网负载均衡路由协议（CLBLR）在路由发现阶段和路由维护阶段，将整个路径中各节点MAC层的总平均估计时延和路径总业务流负载结合起来，共同作为路由选择和路由调整的重要依据，通过双向路径重选方法实现最优路径选择和网络业务流的均衡分布和均衡传输．协议通过禁止中间节点对路由请求进行应答和阻止不必要的路由请求分组，经由重负载中间节点转发，以保证路由发现时能够利用最新负载信息，并避免了节点在重负载情况下成为新建路由的中间节点，使协议具有一定的拥塞控制功能，以间接的方式实现了请求接纳控制．上述措施使分组传输路由很好地避免了拥塞节点，减少了网络瓶颈对网络性能的影响．仿真表明，CLBLR在分组丢失率、平均端到端时延和路由附加开销等方面具有良好性能，其优良的分布式控制特征能适应自组网的动态环境．     

能量高效的ZigBee网络改进路由策略

在分析现有ZigBee网络路由策略的基础上,以节省网络能耗和均衡网络负载为目的,提出一种能量高效的改进路由策略。该策略分别对ZigBee网络的簇树拓扑结构以及基于簇树算法和AODVjr算法的ZBR路由策略进行改进。改进后的路由策略在尽量减少路由开销的同时充分考虑对能量偏低节点的保护。仿真实验验证,改进策略能有效减少网络能耗,均衡网络负载,最大化网络的生存时间。     

能量高效的ZigBee网络改进路由策略

在分析现有ZigBee网络路由策略的基础上,以节省网络能耗和均衡网络负载为目的,提出一种能量高效的改进路由策略。该策略分别对ZigBee网络的簇树拓扑结构以及基于簇树算法和AODVjr算法的ZBR路由策略进行改进。改进后的路由策略在尽量减少路由开销的同时充分考虑对能量偏低节点的保护。仿真实验验证,改进策略能有效减少网络能耗,均衡网络负载,最大化网络的生存时间。     

基于负载均衡的战场自组织网络多径路由研究

移动Ad hoc网络中的多路径路由协议能够减小路由发现延迟,提高网络生存时间,受到了人们的广泛关注.详细分析了AOMDV多路径路由协议的机制和特点,针对多径路由协议在负载均衡时采用的随机转发策略,提出了一种改进的基于AOMDV协议的负载均衡传输方案,该方案能够避免TCP在多径传输时的乱序.仿真结果表明,在不影响UDP性能的情况下,该方法能显著改善TCP的传输性能.     

一种能耗均衡的WSNs动态数据汇聚方法

无线传感器网络一般采用分簇路由协议实现数据的汇聚,这类协议要求Sink节点的位置固定,并通过节点间多跳接力传输,将数据汇聚到Sink节点。由于网络中不同节点承担中继的负载不同,这会导致某些负载过重的节点能量提早耗尽,从而形成网络空洞。虽然某些路由协议在网络能耗均衡方面做了一定的措施,但仍无法较好的解决该问题。为此提出一种能耗均衡的动态数据汇聚方法,该方法的汇聚节点(Sink)为可移动节点,为平衡网络能耗,利用网络节点的能量为Sink节点确定若干个数据汇聚位置。并结合TSP算法规划Sink节点的最佳移动路径,通过对该算法进行大量的仿真,并与现有的一些方案进行比较,验证了该算法在各种性能指标上的有效性。     

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     

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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.