无线传感器网络的L EACH 算法的改进

无线传感器网络是监控远程环境的工具之一.由于能量和存储空间的限制,其路由协议必须维持较小的路由信息并尽可能的减少能量消耗.基于经典的LEACH路由算法,提出了改进:主要体现在对能量和簇头间距的考虑上.最后用Matlab对LEACH算法和改进后的算法进行仿真,证实改进后的算法在网络生存时间和簇负载平衡程度上比LEACH算法有了很大提高.     

一种无线传感器网络路由协议的研究与改进

无线传感器网络由许多具有低功率无线收发装置的传感器节点组成,能够有效地感知、采集和处理网络覆盖区域中的相关信息,并发送给远处的基站进一步处理。由于传感器节点能量有限,路由协议必须尽可能地减少能量消耗,延长网络生命周期。对经典的LEACH路由协议进行研究,并针对簇头节点和基站的通信方式提出改进,用M atlab平台下对LEACH算法和改进后的算法进行仿真分析,结果显示:改进后的算法在延长网络生命周期和减少能量消耗上比LEACH算法有了很大改善。     

无线传感器网络LEACH算法的改进

无线传感器网络是监控远程环境的工具之一,由于能量和存储空间的限制,其路由协议必须维持较小的路由信息并尽可能地减少能量消耗.基于经典的LEACH算法进行了改进,主要体现在对簇头选举的考虑上,把节点的剩余能量考虑到簇头的选举过程中去.最后对经典LEACH算法和改进后的算法进行仿真比较,证实改进后的算法很大程度上延长了网络的生存时间,同时减小了簇中节点的能量消耗.     

一种新的基于LEACH的WSN路由算法

研究无线传感器网络路由算法,无线传感器网络由能量有限的节点组成,因此高效节能的路由算法是无线传感器网络组网的基础.针对低功耗自适应分簇(LEACH)路由算法存在簇首节点选择不合理以及簇首节点与基站在远距离通信过程中能量消耗大的不足,提出了一种改进的LEACH路由算法.改进的算法在簇建立阶段的簇首选举过程中,引入节点剩余能量因素,且进行均匀分簇,有效地降低剩余能量较小和位置不佳节点成为簇首的可能性,均衡了网络的能量消耗,在簇稳定工作阶段,节点间的数据传输采用单跳和多跳相结合的通信方式,从而降低网络能耗.仿真结果表明,与传统的LEACH算法相比,改进的LEACH算法能量均衡性更好,并显著地延长了网络的存活时间.     

无线传感器网络LEACH协议的研究与改进

在分析了无线传感器网络中分层路由LEACH算法的基础上,提出了一种新型选择簇首节点的方法,并通过matlab对改进后的LEACH算法进行了仿真,仿真结果显示改进后的LEACH算法在网络生命周期和网络能量消耗两方面比LEACH算法有很大的提高。     

蚁群算法在LEACH路由协议中的应用

减少网络能量损失,增加网络的生成时间是无线传感网络的重要研究内容。LEACH是针对无线传感网络设计的低功耗自适应的路由算法。但是传统LEACH路由算法存在簇首开销过大、簇规模分布不均匀等问题。针对LEACH算法存在的缺点,从成簇方式和簇头路由拓扑提出改进方案,成簇半径随着距离Sink节点的增加而减小,簇首间采用蚁群算法进行路由优化。实验从网络节点存活的节点数目和节点的平均耗能两个指标对仿真结果进行评价,仿真结果显示改进算法网络的生存时间比传统结果提高了15％,节点平均能耗降低20％。改进算法可有效减少网络的总能量消耗,均衡网络的负载。     

LEACH协议的簇头多跳（LEACH-M）改进算法

节能高效的实现路由转发是路由设计的一个关键点。总结了目前已有的无线传感器网络的传输路由模式,发现早先提出的LEACH协议虽是无线传感网中的低功耗自适应分层路由算法,但会造成簇头节点负载过重。成簇算法是传感器网络中减少能量消耗的一种关键技术。提出的是基于LEACH算法的多跳路由改进算法,并在考虑簇头最优个数的选择下,通过采用簇头之间的多跳算法达到减少能量消耗、延长传感网的寿命的目的。实验表明此方法有效。     

一种基于LEAC日协议的分簇路由算法

低能自适应聚类路由协议(LEACH协议)是为无线传感器网络设计的一种低功耗自适应分层路由协议,具有延长网络生命时间的作用.为了均衡无线传感器网络节点的能耗,延长整个网络的生命周期,通过对LEACH协议的研究,对簇首的选取和簇首与Sink的通信机制进行优化,提出了一种改进的LEACH协议的分簇路由算法.通过Madab仿真实验证明,改进后的LEACH算法在网络生命周期和网络能量消耗等方面比LEACH算法有较大的提高.     

基于leach协议算法的改进与仿真

针对无线传感器网络中传感器能量有限的问题,从路由算法的角度出发,提出LEACH协议的低功耗改进方案。该文找到了使整个网络能量消耗最小的最优簇头数目P,改进LEACH协议中的随机簇头选举方式,同时给出了该算法的数学推导和进行了NS-2仿真实验。仿真实验的结果表明,改进的LEACH算法能够有效的减少传感器网络节点的能量消耗,最大限度的延长整个无线传感器网络的生命周期。     

三维固定分簇异构传感网络路由协议

基于高楼三维空间中家居监测的应用背景,提出了一种三维空间中LEACH路由协议的改进算法:三维固定分簇异构传感网络路由协议(3D-FHSR).在3D-FHSR中,使用了异构网络的方式让部分能量充裕的节点固定充当簇头节点,并且事先划分好簇的区域范围,这样减少了簇头选举时的能量消耗,同时增加了整个网络的能量.3D-FHSR还改进了LEACH协议的通信模式,减少簇间长距离通信的次数.仿真结果表明,3D-FHSR协议比LEACH协议更能延长网络的生命周期.     

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.     

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.     

法律信息库系统

本文分析了法律数据库的结构和特点，介绍了采用面向对象设计方法和超文本数据库技术开发和实现法律信息库系统将作为重要网络资源之一为不同用户进行法律咨询服务。     

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.     

International Journal of Automation and Computing Table of Contents

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Information for authors

正SCIENCE CHINA Information Sciences(Sci China Inf Sci),cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press,is committed to publishing highquality,original results of both basic and applied research in all areas of information sciences,including computer science and technology;systems science,control science and engineering(published in Issues with odd numbers);information and communication engineering;electronic science and technology(published in Issues with even numbers).Sci China Inf Sci is published monthly in both print and electronic forms.It is indexed by Academic OneFile,Astrophysics Data System(ADS),CSA,Cabells,Current Contents/Engineering,Computing and Technology,DBLP,Digital Mathematics Registry,Earthquake Engineering Abstracts,Engineering Index,Engineered Materials Abstracts,Gale,Google,INSPEC,Journal Citation Reports/Science Edition,Mathematical Reviews,OCLC,ProQuest,SCOPUS,Science Citation Index Expanded,Summon by Serial Solutions,VINITI,Zentralblatt MATH.     

Erratum to: Fast global kernel fuzzy c-means clustering algorithm for consonant/vowel segmentation of speech signal

正Erratum to:J Zhejiang Univ-Sci C(ComputElectron)2014 15(7):551-563doi:10.1631/jzus.C1300320The original version of this article unfortunately contained mistakes.Algorithm 6 should be as follows:Algorithm 6 FGKFCM-F clustering Input:(1)X={x_1,x_2,…,x_N},,x_iR~d,i=1,2,…,N,the dataset;(2)C,1C≤N,the number of clusters;(3)ε0,the stopping criterion;     

Journal of Zhejiang University-SCIENCE C (Computers & Electronics) Total contents

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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.