无线传感器网络分簇拓扑的覆盖区域节点调度优化算法研究

利用区域分割的方法建立了一种覆盖区域冗余节点的优化调度机制,实现对完全覆盖区域内冗余节点的休眠调度,并将该机制引入无线传感器网络的分簇结构中,提出一种基于分簇拓扑的节点调度优化算法。算法通过控制簇内冗余节点进行休眠,减少簇首的数据通信量和簇成员中工作的冗余节点个数,降低了网络能耗。仿真结果表明,与未考虑冗余节点休眠调度的分簇算法相比,该算法有效提高了网络能量利用率,延长了网络生命期。     

基于差分算法的异构无线传感器网络多重覆盖节点调度方案

针对部署区域中存在多个不同覆盖质量需求的目标,本文提出一种基于多重覆盖算法的异构节点调度机制。该算法在满足区域覆盖要求和重点区域监测目标多重覆盖的要求,及节点能量的约束条件下,以网络的有效覆盖率最大和工作节点数目最少为目标,借助改进的差分算法来对节点状态进行优化达到提高网络覆盖性能和降低网络能耗的目的。仿真结果显示,本文的算法在满足热点目标监测要求的前提下,最大限度地兼顾网络的区域覆盖质量,减少了网络的能耗;较之随机调度算法,本文算法在覆盖率和网络能耗方面优于后者。     

基于鱼群算法的无线传感网络覆盖优化策略*

无线传感网络是能量受限的网络,有效覆盖和能耗是衡量其性能的两个重要指标。将最大化网络覆盖率和最小化工作节点数作为网络优化目标,建立了网络覆盖优化的数学模型,并利用鱼群算法并行寻优、收敛快速的特性,提出了一种基于鱼群算法的覆盖优化策略。仿真实验表明,该算法能求解最优覆盖工作节点,并可以改进网络节点调度的实时性。     

基于能耗均衡的WSN连通覆盖集构建算法

为提高无线传感器网络的能量利用率,提出一种基于能耗均衡的连通覆盖集构建算法EBACCS。该算法以概率覆盖模型为基础,采用Voronoi图划分目标区域,获得网络冗余节点,根据能量权值函数,从冗余节点中选出必要的连接节点建立一个优化的连通覆盖集。理论分析和仿真实验结果表明,EBACCS能够保证网络的连通性与覆盖性,均衡节点能耗,延长网络寿命。     

分布式无线传感器网络度覆盖算法

传感器节点在高密度部署和满足一定覆盖条件下,有效地进行覆盖控制和减少能量消耗以及延长网络生命周期是无线传感器网络研究的重点课题,为此,提出一种分布式的度覆盖算法。该算法利用贪心算法和几何图形学相关理论知识对覆盖区域关键节点进行优化覆盖,通过节点状态调度机制转换,可以有效地降低网络能耗,提高了节点覆盖性能的同时优化了节点的数量。仿真实验结果表明,该算法能够以较小的代价提高整个网络的生存周期,有更好地适应性和稳定性。     

一种多目标的覆盖优化策略在WSNs中的应用

针对目前无线传感器网络（WSNs）能量均衡覆盖策略大都基于节点静态感知能耗的不足,提出一种基于节点的动态能耗和网络覆盖率的多目标覆盖优化策略.该优化覆盖策略将动态路由协议引入到覆盖控制优化中,计算覆盖区域在不同节点分布下的动态通信能耗和网络的剩余能量,再结合区域覆盖率构成对覆盖和能量综合指数评价的优化函数.最后利用改进差分进化算法和差分进化算法对优化函数进行仿真,并利用覆盖结果验证策略的有效性.仿真结果表明：提出的覆盖优化策略既能使网络达到较高覆盖率,同时又能保证网络的能耗动态均衡,并将改进差分进化算法与常规差分进化算法比较,结果表明：前者克服了早熟现象,覆盖和能量的综合优化函数值更高,达到了6.184.     

改进的无线传感器网络覆盖区域节点调度算法

节能覆盖对于提高无线传感器网络的性能有着重要的意义.针对当前传感器网络的算法中存在的热区问题,提出一种在传感器网络非均匀分布部署下的基于能量预测的节点覆盖调度算法.该算法首先对网络中的节点进行非均匀部署,离基站距离较近区域部署的节点密度较大,而较远的密度小,然后综合考虑节点覆盖效率和能量消耗进行节点调度,从而使能量消耗更加均衡,最后对该算法进行了仿真实验和性能分析.仿真结果表明与当前经典的覆盖节点调度算法相比,该算法提高网络覆盖率、降低了网络能耗,且网络生命周期也相应的延长,能够保证网络内大多数节点达到能耗均衡.     

一种面向目标的有向传感器网络连通覆盖算法

针对传统的有向传感器网络目标覆盖算法只考虑网络覆盖率而不能保证网络连通性的问题,利用目标点部署圆内覆盖最多邻居目标点的候选节点集合和整数线性规划(ILP)模型设计了一种面向目标的连通覆盖算法(CTA)。该算法通过建立目标部署圆内覆盖最多邻居目标点的候选节点集合对随机部署的节点进行初步调度,在此基础上,通过ILP模型找出实现目标检测,并保证整个网络连通性的最少节点数和最佳位置的节点集合。仿真实验表明:CTA在保证目标覆盖率的前提下,不仅极大地降低了网络部署成本,而且保证了网络连通性。     

EasiFCCT:一种保证连通性的传感器网络局部覆盖算法

调度节点轮流工作可以有效延长网络寿命,然而现有的调度协议大部分需要地理位置信息,引入了额外的负担;一些不需要地理位置信息的节点密度控制算法又无法保证有效的网络覆盖度.此外,已有的分析证明了随机算法可以以较大概率保证一定的网络覆盖度,但是因其没有考虑到节点的非连通性会导致网络出现不连通的情况,所以具有一定局限性.提出的局部覆盖算法在随机调度的基础上同时考虑节点的连通性,可以保证网络在具有一定的有效覆盖度的同时能够连通工作.仿真结果表明,算法在网络有效覆盖度方面要优于已有的工作,同时由于新算法建立在随机调度的基础上,因此其复杂度低,较易实现.     

基于目标覆盖的异构有向传感器网络分布式节点调度策略

针对无线传感器网络服务质量会随着网络运行而下降的现象, 研究随机部署的有向传感器网络的节点调度问题, 提出分布式的节点感知方向调节算法, 各节点利用相邻节点间的信息交换, 计算出各自的最佳感知方向, 从而使得网络在满足覆盖需求的同时减少活跃节点数目, 进而达到降低能耗、提高通信质量的目的. 为均衡网络能耗, 进一步设计了冗余节点调度协议, 周期性地重构网络拓扑. 仿真结果表明了所提出算法的有效性.     

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.     

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