带有重叠区域的多跳非均匀分簇路由算法

能耗作为衡量无线传感器网络性能的一项重要指标,通常将延长生命周期、均衡能耗作为网络协议重要的设计目标.针对静态、异构、非均匀分布的网络模型,设计带有重叠区域的分簇及簇内单跳、簇间多跳的路由算法 ----- OMU分簇路由算法,该算法中簇头不再作为数据转发节点,而主要用于簇内数据的接收与融合.通过综合考虑节点剩余能量、节点密度及与基站的距离进行簇头选举并进行分簇,形成簇间重叠区域,产生用于数据转发的中继节点.同时,建立簇头与中继节点轮换机制以达到节点能耗均衡的目的,并为每个节点建立能量最省的多跳数据传输路径.仿真结果表明,所设计的分簇路由算法,特别是在大规模部署的无线传感器网络中,能有效减少和均衡能量消耗.     

基于CFSFDP聚类算法的WSNs高能效分簇路由算法

为进一步降低无线传感器网络在周期性数据收集过程中的能量消耗,提出一种基于CFSFDP聚类算法的能量高效分簇路由算法。算法首先采用CFSFDP聚类算法对网络分簇进行集中控制,使网络各簇得到均衡分布的同时能够降低网络中的控制包开销;其次在簇头、副簇头及中继节点的选举公式中增加动态权重因子保证数据传输的可靠性;最后在选择下一跳中继节点时加入簇内能耗因子使各簇能耗能够更加均衡地下降。仿真结果显示,该算法网络生存周期较LEACH、KBECRA、CHTD-M算法均有显著提高,表明改进算法在降低和均衡网络能耗上具有优越性。     

能耗最优的LEACH协议改进

针对LEACH协议在簇头选取、数据通信方面的不足,提出改进后的AD-LEACH协议。根据节点的分类,修正簇头当选概率,使簇头选取均衡了能耗、距离、节点密度的影响。通过节点位置模糊匹配的方法将全网划分为若干个均匀大小的网格。数据传输阶段以能量利用率最高为目的,基于最佳转发距离选择转发节点。仿真结果表明,AD-LEACH协议有效降低和均衡了网络能耗,达到了能耗最优的目的。     

负载均衡的水声传感器网络多跳非均匀分簇路由协议

针对现有水声传感器网络分簇路由协议在簇头选举阶段和数据传输阶段中的不足,设计一种负载均衡的多跳非均匀分簇路由协议(load-balanced multi-hop unequal clustering routing protocol,LBMUC)。该协议基于节点的剩余能量及相对距离,计算节点竞争半径和节点综合属性值,改进优化簇头选举,使得簇头节点分布更加合理,并得以随着剩余能量的变化自适应的调整簇的规模,有效均衡节点的能量消耗;在建立簇间多跳路由阶段,综合考虑节点剩余能量、位置及相邻簇的规模对路由选择的影响,引入中继节点代价函数选择最优中继节点,均衡节点能耗,延长网络生命周期,降低网络丢包率,提高网络性能。仿真实验结果表明,LBMUC协议均衡了节点能耗,有效延长了网络生命周期,降低了数据丢包率。     

能量均衡的无线传感器网络多跳非均匀分簇算法

针对分簇协议中存在的簇头选择不合理会造成能耗过大以及网络整体能耗不均衡的问题,提出了一种能量均衡的多跳非均匀分簇算法(EBMUC)。协议首先选择剩余能量大于邻节点平均剩余能量的节点为候选簇头,候选簇头交换消息计算并比较适应值选出最终簇头;簇结构采用非均匀分布形式,节点入簇时计算代价值函数,在引入的代价值函数加入簇头剩余能量因素,防止簇头成员数目过多致使负载过大;数据的传输采用单跳和多跳结合的方法,簇间距离大于设定值时引入中继节点协助簇头间的数据传输,节约了簇头能量。仿真结果表明,EBMUC协议可有效节约簇头能量,均衡了整个网络的能耗,使网络生存周期得到了延长。     

一种新型能耗优化的无线传感器网络成簇算法

能量消耗一直是限制WSN广泛应用的热门问题之一,能源容量的大小对各个传感器节点产生重要的影响.针对WSN中能耗过快,以及网络区域内能量消耗不均衡而导致的网络生命周期缩短的问题,同时为了提高WSN的能量利用率,提出了一种新型能耗优化的无线传感器网络非均匀成簇算法(UCNE).该算法首先根据节点的历史能耗来竞选簇头节点,将整个网络划分为不均匀的簇群从而平衡簇内节点通信与簇间节点通信的能耗.其次设立新的能量阈值作为网络重新分簇的标准,减少了频繁分簇造成的不必要的控制消息能耗.最后为了降低簇头节点的负担,竞选副簇头节点作为中继转发节点转发主簇头加工的数据并根据权值选择向前向簇头节点传递数据.通过对比相关协议,UCNE协议在平衡网络能耗,延长网络寿命方面表现更优.     

无线传感网中一种能量均衡的分簇路由算法

无线传感器网络的一个极富挑战性、极其关键的课题就是降低能源消耗以延长网络寿命。文中提出了一种能量均衡的分簇路由算法（CRA—EB）。算法分为三个阶段,即：簇头选择、聚的生成及数据传输。首先基于节点的剩余能量和邻居节点数目来选择簇头。然后每一个非簇头节点根据簇头代价值加入自身通信范围内的簇头。在数据传输阶段,CRA-EB首先在簇内使用单跳通信,然后在簇间使用多跳通信。对簇间通信,簇头以自身为起点对通往基站的各路径代价进行衡量,同时选择其他簇头作为中继节点在这些路径上转发数据。仿真实验结果表明,与LEACH和DEBR算法进行比较,CRA-EB算法在能耗和活跃节点数量方面的性能表现更加高效。     

WSNs中基于动态竞争半径的非均匀分簇路由协议

针对LEACH协议成簇规模不合理、网络能耗不均衡的缺点,成簇阶段在LEACH协议的基础上,通过引入基于平均理想簇半径的簇首能量判决因子、"热区"关联判决因子、簇内紧凑性判决因子和节点密度判决因子来改进选举候选簇头的阈值计算公式。候选簇头以一种改进的动态竞争半径来竞选成为真正的簇头。数据传输阶段综合考虑簇头剩余能量、链路代价和数据传输方向3个因素选择下一跳路由。仿真实验结果表明:改进后的算法体现出较好的自适应性,能有效均衡网络能耗、延长网络生命周期。     

多媒体传感器网络中基于两跳簇结构的图像传输方案

与传统无线传感器网络节点能量绝大部分消耗在无线收发上不同,无线多媒体传感器网络中数据处理与传输能耗具有“均匀“分布的特点.通过分析表明,传统无线传感器网络簇结构下的数据传输策略并不适合于无线多媒体传感器网络.因此提出了一种基于两跳簇结构的图像传输方案,通过增加中继节点负责图像的压缩编码和转发,在减小相机节点图像传输能耗的同时,大大缓解了相机节点和簇头的图像处理能耗压力.仿真结果表明,该图像传输方案极大的延长了网络的生命周期,非常适合于能量有限的无线多媒体传感器网络.     

基于能量福利函数的传感网络节能路由算法

针对无线传感器网络能耗不均衡、能量利用率低等问题,在PARPEW协议基础上提出了一种基于能量福利函数的传感网络节能路由算法。通过在簇形成阶段引入能量代价开销公式和能量福利函数确定簇成员和最终簇头,并且对选举临时簇头时的阈值进行了优化;簇间路由阶段,采用单跳与多跳结合方式,中继节点选举时的权值函数加入了簇内节点个数、已当选过中继节点次数因素。仿真实验表明,与LEACH和原PARPEW协议相比,改进算法均衡了网络能耗,提高了能量利用率,延长了网络生存周期。     

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.     

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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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