一种能量均衡的无线传感器网络分簇路由协议

由于无线传感器网络节点能量有限,为均衡无线传感器网络节点之间的能量消耗,提高整体网络的生命周期,针对LEACH协议中簇首选举时未考虑节点剩余能量因素、随机分簇等不足,提出了一种改进的LEACH协议.改进的LEACH协议在簇首选举时,以节点的剩余能量作为重要参考依据,优化节点担任簇首的概率.仿真结果表明,与传统的LEACH协议相比,改进的LEACH协议达到了能量消耗均衡的目标,从而延长了网络的生存寿命.     

基于能量高效的无线传感器网络LEACH协议改进

针对无线传感器网络节能问题,详细分析了经典分簇协议——LEACH,在其基础上针对LEACH的不足进行改进,提出了一种能量高效的分簇路由协议。该协议在簇头选举的算法中纳入节点剩余能量作为参数,提出各簇独立进行的簇头轮换机制,控制簇头在簇中的分布和各簇成员节点数目,并采用基于阈值的单跳与多跳相结合的簇间通信方式。仿真结果表明,改进后的协议较LEACH能够有效节约节点能量,均衡网络各节点消耗,显著延长了网络生存周期。     

无线传感器网络路由协议LEACH的研究与改进

经典的分簇路由协议LEACH在无线传感器网络中有着非常广泛的应用,但LEACH协议在成簇时没有考虑簇头节点的能量和位置,所以网络能耗较大。针对LEACH协议能耗较大的问题,为延长网络生存期,在LEACH协议的簇头选择公式中加入节点剩余能量和距离的参数,提出改进的LEACH协议。在网络模拟软件NS2平台下,对改进的LEACH协议与原LEACH协议进行仿真比较分析,结果表明改进后的协议中各个节点能耗均衡,避免个别节点过早衰亡,可以延长网络生存期。     

基于覆盖率的无线传感器网络LEACH协议研究及改进

无线传感器网络中如何对节点能量进行优化使用是无线传感器网络应用中的关键技术之一.本文针对现LEACH协议的分簇及覆盖率方面进行改进.主要根据邻居节点的数量,通过对簇头节点分布及簇内实际覆盖率的优化来提高整个网络寿命.由MATLAB仿真结果表明:与LEACH协议相比,LEACH-C协议不仅保证较高的覆盖率,并能有效的延长...     

一种基于LEACH协议改进的簇间多跳路由协议

为了均衡无线传感器网络的能量消耗,延长网络的生存时间,在研究几种基于均匀分簇和非均匀分簇的路由协议基础上,提出一种基于LEACH协议改进的簇间多跳路由协议。该协议引入能量因子和距离因子修正了LEACH协议的阈值函数。在簇间通信过程,簇头节点与Sink节点之间采用多跳通信方式,簇头与簇头之间形成一条通向Sink节点的优化路径。实验结果表明,相比于LEACH协议和EEUC协议,本文提出的新协议能够有效的均衡网络的能量消耗,延长无线传感器网络的寿命。     

基于优化簇半径的WSNs非均匀分簇路由

为了有效解决无线传感器网络分簇路由协议中,靠近SINK节点的簇头因特发大量数据而过早耗尽能量,提出了一种优化簇半径的非均匀分簇路由协议(UCOR),其核心思想是通过优化簇半径对无线传感器网络进行合理分簇,使靠近SINK节点的簇规模小于远离SINK节点的簇.仿真实验结果表明,与EEUC和LEACH等路由协议相比UCOR路由协议有效地均衡了节点能量消耗,显著地延长了网络生命周期.     

无线传感网络中基于综合因素的分布式路由算法

近年来由于在多方面的广泛应用,无线传感器网络受到了越来越多的关注.然而限于无线传感器网络自身的限制,如何更好地节省能量,仍为无线传感器路由协议设计中面临的主要问题之一.LEACH等基于分簇的路由协议通过成簇来减少能量消耗,但是成簇过程却带来额外消耗以及冗余.对LEACH协议中簇头生成算法进行了研究并提出了改进,提出了基于节点能量、节点距离以及节点度的分布式优化算法,并对优化算法进行分析与仿真.仿真试验表明,基于综合因素的分布式簇头选举算法优化了簇头选举方式和簇头的分布,从而节省了能量消耗,延长了网络生存周期.     

基于能量优化的无线传感器网络分簇路由算法研究

无线传感器网络的路由协议设计要同时关注单个节点的能耗及整个网络能量的均衡消耗.分簇算法能有效解决节点能耗受限与不同节点能量开销不平衡问题.在分析了传统分簇路由LEACH(low energy adaptive clustering hierarchy)协议中选择簇头算法不足和当前一些典型基于LEACH思想的路由改进算法...     

基于LEACH协议节能路由算法的研究与优化

针对LEACH(Low-Energy Adaptive Clustering Hierarchy)协议在分簇算法中存在的未考虑节点的剩余能量,簇头节点分布位置不合理等缺陷,提出基于LEACH协议的节能路由改进算法。在原有协议的基础上,优化了成簇的条件,充分考虑了剩余能量与相对位置,使得无线传感器网络的寿命得到进一步延长。仿真实验结果表明改进后的算法有效降低了网络能耗,提高了无线传感器网络的性能。     

基于无线传感器网络LEACH协议的改进算法

基于无线传感器节点的位置信息及剩余能量,提出了一种基于LEACH协议的改进算法-PE-LEACH协议。PE—LEACH协议基于节点的位置信息进行分簇,基于节点的剩余能量及位置信息进行簇头的选择,当簇头距离汇聚节点较远时采取中转方式传送数据。较好的平衡了网络能量负载,延长了网络的生命周期。仿真结果表明：PE—LEACH协议与LEACH协议相比,提高了网络能量的利用率,延长了节点的生命周期。     

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.     

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.     

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