一种基于长链竞争机制的传感器网络能量空洞研究算法

在无线传感器网络中,越靠近Sink的节点由于承担更多子孙节点的数据转发,能量消耗越快,极易形成“能量空洞”,大大缩短了网络生命周期。针对能量空洞的问题,提出一种基于长链竞争机制的k-leader算法以延长网络生命周期。k-leader竞争算法将Sink一跳范围内节点的一部分数据量交给距离Sink一跳距离以外两跳范围以内的节点,通过长链直接发送给Sink节点,从而减轻Sink周围节点的负载。同时,k-leader的置换算法又保证了节点能够根据能量损耗的情况轮换担任leader节点和通过长链发送数据的节点,达到能量消耗均衡的目的。分析了leader节点的数量k的优化取值,并通过仿真验证了k-leader算法在网络生命周期、网络能耗均衡等指标上的性能。     

基于小世界的传感器网络查询能量空洞问题

靠近Sink的传感器节点因为需要转发来自其它节点的数据而承担了更多的通信负载,这些节点往往更早地耗尽自身能量而有更短的生命周期,这种现象被称为“能量空洞”问题.文中基于小世界思想,通过向Sink节点添加一些长链,减少Sink周围节点转发数据的数量来缓解能量空洞的出现,从而延长网络的生命周期.首先对等距传输的网络进行了能耗分析,然后提出采用小世界的策略缓解能量洞的出现,从理论上分析了长链的位置和数量对能量消耗和网络生命周期的影响,提出了一种实用的小世界网络实现方法.仿真实验验证了理论分析结果.     

机会移动传感网中基于感知方向的数据收集

机会移动传感网中数据收集策略既要保证传输成功率、减小网络开销,也要尽量降低传感器的能量消耗,从而延长网络生命期。遵循简单实用的原则,提出了基于方向感知的数据收集策略(Data Gathering based on Perceptive Direction,DGPD)。当两个传感器相遇时,以距离它们最近的Sink节点为参照点,分别计算各自的感知方向。把感知方向作为一个重要参数来确定两个相遇传感器的消息转发路由,把消息转发给更有利于接近Sink节点的传感器,从而提高数据收集成功率,减少过多的消息转发。模拟实验结果表明,这种策略可以有效地完成数据收集,并获得较高的网络性能。     

移动传感器网络中能量均衡分簇及移动策略

无线传感器网络各节点能量有限,如果数据收集节点（Sink）能够移动,则可以大大节约节点能量,从而延长网络的寿命。首先提出一种能量均衡的分簇算法,根据节点地理信息进行分簇,使得节点耗费总能量尽可能小的同时,使各簇能量消耗基本平衡;在此基础上提出一种Sink 移动策略,Sink 优先选择能量较充足的簇收集信息。仿真结果表明,与传统的随机移动算法相比,提出的算法能够显著平衡各族之间的能量消耗,并减少总的网络能量消耗,从而提高网络的寿命。     

能量有效和延迟敏感的无线传感器网络数据收集协议

利用移动Sink进行数据收集是无线传感器网络数据收集的一个趋势。本文提出一种能量有效、延迟敏感的移动数据收集协议（Energy—efficient and Delay—Sensitive Data Gathering Protocol for Wireless Sensor Networks,简称EEDS）。EEDS中,移动Sink在网络中穿行,从代理节点收集传感器节点监测到的数据。为了减少数据收集的延迟,采用类TSP（Traveling Salesman Problem）的解决方法,确保移动Sink在各个代理节点中收集数据时,始终选择一条最短路径在网络中行走。模拟仿真表明,提出的数据收集协议在延长网络生命周期以及减少数据收集延迟方面都有显著的优势。     

能量有效的无线传感器网络数据收集协议

针对无线传感器能量有限问题,提出能量有效及均衡的数据收集协议(EEBDGP)。利用移动Sink(MS)进行实时数据收集,采用主动重定位MS靠近数据流量大的邻居区域的方法,缩短大流量数据的传输路径,降低传感器节点能量消耗。在数据流量相对均匀而MS的数据转发节点能量低于阈值时,MS移向能量最大的邻居节点,使传感器节点能量消耗达到均衡。实验结果表明,EEBDGP能量有效且能量均衡,并能延长网络生命期。     

基于最小生成树的非均匀分簇路由协议

针对无线传感器网络中利用分簇技术,簇首到Sink节点通信采用多跳路由方式容易引起"能量空洞"的问题,提出了基于最小生成树的非均匀分簇路由协议.该协议在簇首选举阶段,以节点剩余能量、节点度、节点能量消耗速度为权重计算簇首竞争等待时间,选用簇首竞争等待时间小的节点为簇首,以均衡能量;簇形成后,以剩余能量、簇间的距离和能量消耗为参数构建基于最小生成树的最优传输路径通过多跳方式将数据发送到Sink节点.仿真结果表明,该路由协议能有效均衡能耗,延长网络生命周期,延缓"能量空洞"的形成.     

WSN数据收集中移动Sink的路径规划和簇头节点选取问题的综合研究

针对较大规模的无线传感器网络通过多跳传输进行数据收集而引起的能量空洞问题,提出了一种基于移动Sink的簇头节点数据收集算法(MSRDG),该算法基于图论原理,在满足时延性的条件下,综合考虑了普通节点到簇头节点路由和移动Sink遍历路经选取的问题,构建了一条通过的簇头节点尽可能多的移动轨迹。通过NS-2仿真软件对算法的性能进行评估,结果显示出该算法能减少数据的多跳传输,降低无线传感器网络节点的能量消耗,延长网络寿命。     

无线传感器网络中一种负载均衡的跳跃式路由协议

如何实现能量的高效利用,延长网络的生命周期一直是无线传感器网络研究的热点.在传统的路由协议中,靠近基站的节点由于要转发其它节点的数据容易过早耗尽能量而失效.本文基于传感器节点传输功率可调这一假设,提出了一种负载均衡的跳跃式路由协议(LBR).协议中每个节点维护K跳的路由表.在需要发送数据时,剩余能量较少的节点将数据发送给下一跳节点,而剩余能量较多的节点可以跨越多跳进行数据传输.从而均衡了节点的能量消耗.模拟结果表明,采用该协议建立的路由,不仅具有延时小,数据传送的路径长度短,维护简单等优点,并且能够改善网络的负载均衡,极大地延长网络的生命周期.     

一个能量收集无线传感器网络路由协议

针对周期性数据收集无线传感器网络应用,提出一个能量收集无线传感网络路由协议EHRP,以高效的能量估计和链路评估为基础,通过基于收集能量优先的选路实现多跳报文转发,构建起能量均衡消耗的多跳传感器网络.仿真结果表明在具有能量收集能力的传感器网络中,EHRP能够充分利用节点的能量收集能力,实现网络能量均衡,延长网络的生命周期,同时提高了数据传输的可靠性.     

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