Ad hoc中基于分簇的多路径路由协议

在Ad hoc网络路由协议中,分簇路由具有扩展性强、数据融合简单、能量利用高效等特点,成为当前路由研究的重点。在研究了一些分簇算法和多路径路由算法基础上,提出基于簇指挥路径的多路径路由算法(CDPMR)。仿真表明基于簇指挥路径的多路径路由算法,与平面的多路径路由算法相比,扩展性好,控制负载低,与其它的基于分簇路由算法相比,网络拓扑稳定,减少网络重构开销带来的通信代价,有利于均衡网络能量消耗,延长网络生命周期。     

无线传感器网络CDPMR路由算法研究

在无线传感器网络路由协议中,分簇路由具有扩展性强、数据融合简单、能量利用高效等特点。基于一些分簇算法和多路径路由算法,提出基于簇指挥路径的多路径路由算法（CDPMR）。仿真结果表明,与其他路由算法相比,CDPMR扩展性好,控制负载低,网络拓扑稳定,能减少网络重构开销带来的通信代价,有利于均衡网络能量消耗,延长网络生命周期。     

MANET中基于簇的多路径动态源路由(CMDSR)

大量研究表明移动自组网（mobile ad hoc networks，MANET）的特性使得提高无线网络路由协议的可扩展性成为一个挑战性的工作．根据网络动态特性，提出了一个基于簇的多路径动态源路由机制（CMDSR），该机制利用分簇的层次结构来有效搜索多路径，利用多路径并行传输流量．协议的主要思想是在分簇算法中将网络分成单元簇（1-cell cluster）和中心簇（2-server cluster）两级层次结构，将路由发现程序放在2-server层来防止类似DSR路由发现过程的泛洪，实现路由开销最小化，提高网络的可扩展性，能够有效地处理节点数量增大和节点密度增大的问题．此外，CMDSR通过选择可靠的路径和发送端-端的可靠性软保证的方法解决了可靠性问题，因而具有良好的性能．在OPNET环境中实现了这个协议，结果表明，CMDSR能够平衡网络负载，有效地处理网络拓扑的易变性，从而有效地提高网络的可靠性和鲁棒性．     

蚁群优化的无线传感器网络路由仿真研究

针对无线传感器节点提供能鼍的电池有限,因此无线传感器网络的路由设计应有效地利用能量.为了有效地延长网络的生命周期,提出了一种基于蚁群优化的尤线传感器网络路由算法.首先根据节点剩余的能量进行簇头选择;然后通过简单易于实现、支持多路径的蚁群算法进行路由选择,通过相邻簇头节点间广播各自的距离和剩余能景信息,在整个网络中建立与更新簇头间的蚁群信息素浓度;最后根据蚁群信息素浓度计算各相邻簇头被选择作为下一跳的概率,从而形成网络簇间路由.在NS2平台下进行了仿真实验,实验结果表明,与LEAcH算法相比,减少了平均能耗,网络存活节点数增加,有效地延长了网络生命期.结果证明,蚁群算法在无线传感器网络中能够很好的找到最佳路由.     

无线传感器网络多路径簇头链分簇式路由算法

本文分析了无线传感器网络路由协议的研究现状,重点研究了分簇式路由算法,并提出一种改进的算法--基于能量和距离的多路径簇头链（MCBED）算法。该算法不仅改进了簇头节点的选取方法,而且根据需要产生替补簇头节点,形成多路径簇头链。理论分析和仿真实验表明,改进后的算法分簇更加合理,提高了网络健壮性,节省能量,均衡节点能量消耗,显著延长了网络生存时间。     

基于混合分簇的无线传感器网络路由协议

提出一种基于混合分簇的无线传感器网络路由协议(EEHCRP).该协议综合了集中式和分布式分簇的优点,使得簇头分布更加均匀并减少了簇重构的开销.在此分簇的基础上,使用改进的多路径路由树建立簇问路由,使其不但可以减少重传次数,提高数据传输的稳定性,还缓解了簇头的能耗.然后使用CMMBCR算法建立一条能量高效的簇内路由.仿真结果表明:该协议较之经典的分簇路由协议不仅有效地均衡了网络能量消耗、显著地延长了网络生命周期,而且具有较强的鲁棒性.     

基于簇和随机漫步的多路径路由算法

针对无线传感器网络中已有的路由算法的不足,提出了一种基于簇和随机漫步的多路径路由算法;首先,利用改进的基于权值的分簇算法对网络分簇;然后,利用改进的随机漫步算法构建从簇首到汇聚节点的多条不相交路径;最后,根据每条路径的性能参数(节点剩余能量、路径能耗等)动态地选择一条路径进行数据传输;仿真结果表明,该算法可以有效地平衡网络负载和延长网络生存期。     

一种智能多路径路由及子流分配协同算法

传统单一路径的传输机制难以满足当前以智慧城市为代表的新一代应用对时延、丢包率等网络性能的要求,而现有多路径传输机制在路由算法及子流分配等方面不能根据网络实时状态调整且互相缺乏协同。引入强化学习理论并结合软件定义网络,提出多路径路由及子流分配协同算法。基于Q-learning设计多路径路由算法,并从策略协同角度对其进行改进,实现路由与子流分配的相互协同。在此基础上,通过Q-value的回环消除方法保证路由准确性并提高算法收敛速度。实验结果表明,该算法在网络负载动态变化过程中能实时调整最佳的多路径路由及子流分配协同策略,提高了传输成功率。     

基于移动Agent的无线多媒体传感器网络QoS路由算法

无线多媒体传感器网络(WMSNs)的主要特点包括资源有限、时延敏感和数据冗余性高。此外,音视频数据流传输所需的带宽是多媒体传感器节点所能承受的最大传输带宽的几倍。上述因素使得WMSNs的QoS 路由成为一个亟待解决的关键技术问题。鉴于此,首先通过基于等差数列的非均匀分簇算法对网络区域进行划分,然后在此网络拓扑上,提出一种基于移动Agent的WMSNs的QoS路由算法(MAQR)。MAQR由路由发现和数据传输两个阶段组成。在路由发现阶段,采用移动代理技术完成多路径路由发现。在数据传输阶段,采用多优先级多路径传输模型把数据流进行分类,并利用流量预测算法实现网络的负载均衡。最后,在NS-2平台上实现了MAQR,通过与同类算法进行仿真比较,发现MAQR较之同类算法能够明显地提高音视频传输的服务质量。此外,MAQR算法比同类算法的能耗更低。     

基于SDN的胖树数据中心网络多路径负载均衡算法研究

软件定义网络SDN(Software Defined Network)通过将网络设备的控制层与数据层分离解耦,能够实现网络的集中控制和流量的灵活转发,因此被广泛应用于数据中心等相关领域。在数据中心网络中,为了提高网络的带宽和吞吐量,多采用具有多路径特性的层次型网络拓扑结构,如胖树拓扑结构。然而传统路由算法对多路径的支持非常有限,无法充分利用网络剩余带宽。重点研究基于SDN的胖树数据中心网络多路径负载均衡算法。利用SDN网络集中控制的特点,获取多路径实时状态信息,计算各路径当前可用带宽,根据数据流的带宽需求选择最佳转发路径。实验结果表明,该算法无论在降低网络传播时延还是在提高网络吞吐量等方面都优于传统路由算法,能够实现胖树数据中心网络的多路径负载均衡。     

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.     

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)

正~~     

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