无线传感器网络一种不相交路径路由算法

无线传感器网络经常被用来采集物理数据,监测环境变化.由于低功耗无线通信不确定性、链路质量不稳定性以及节点失效等问题,传感器网络很容易导致路由数据包丢失.为了提高网络路由的可靠性,人们提出多路径路由算法.多路径路由中源节点到目的节点的多条路径可能含有公共节点,或者公共边,如果公共节点或者公共链路失效,则这个数据包也丢失,因此又有人提出不相交多路径路由算法.不相交多路径路由算法又分为链路不相交多路径路由算法和节点不相交多路径路由算法.提出了一种不相交路径路由算法,可以将感知节点采集到的数据通过不相交路径传送到汇聚节点,提高路由的可靠性.而且,这个算法还可以很方便地应用到多Sink节点的网络当中.该路由算法用到的路由表大小为|K|,其中|K|表示路径数.算法的运行时间复杂度是O(|L|),其中|L|表示网络中的边数.     

无线传感器网络多路径缠绕模型及其容错路由机制

针对无线传感器网络(WSN)不相交多路径路由中的路径过长问题和缠绕多路径路由中的容错削弱问题,提出一种多路径缠绕模型及其容错路由机制。首先,提出将多路径缠绕量化的思想,通过建立多路径缠绕模型将多路径的缠绕性量化,并通过容错概率模型建立多路径缠绕性与路由容错性的理论关联;其次,基于多路径缠绕模型,通过局部调整多路径的相交度建立容错路由机制。实验结果表明,在典型多路径路由算法——顺序分配路由(SAR)和能量有效容错多路径路由(EEFTMR)上应用该容错路由机制,能有效提高算法的数据包传输成功率,并一定程度上优化算法的能量有效性和端到端传输延迟。     

Ad Hoc网络多路径需求路由及路径熵选择算法

无线移动Ad Hoc网络是一种不依赖任何固定基础设施的移动无线多跳网络.由于其动态性和资源的限制,在Ad Hoc网络中提供多路径路由是一个重要的研究课题.描述了一种Ad Hoc网络中基于信息熵选择的稳定多路径路由算法(stability multipath on-demand routing,简称SMDR),提出了路径熵的度量参数,并利用路径熵来选择稳定的、长寿命的多路径,减少了重构路由的次数,从而在网络拓扑频繁变化的Ad Hoc网络环境中较好地提供QoS保证和提高数据传输率.仿真结果表明,SMDR协议改进了分组传输率、端到端时延和路由负载率.SMDR协议为解决动态的Ad Hoc网络多路径传输提供了一种新的有效途径.     

一种干扰分离多路径路由协议的设计与实现

无线多媒体传感器网络在传输音频、图像、视频等媒体信息时要求更加苛刻的端到端传输性能.通常的解决办法是采用多路径传输技术,利用源节点到目的节点之间多条可用路径并发地进行数据传输.为了尽可能降低传输延时,传统的多路径协议通常选择跳数之和较小的路径,致使所建路径彼此相互靠近而通信干扰增大,最终导致传输性能降低.提出一种基于干扰分离的多路径路由协议IDMPR,在寻找多路径时,按SINR模型对路径干扰进行计算,从而保证所选路径之间不存在干扰或尽可能降低干扰.仿真实验显示IDMPR协议所选路径通信干扰较小,传输率和传输延时等性能较传统协议有一定的提高.     

多路径路由网络负载均衡算法研究

研究多路径路由网络通信优化均衡问题,由于网络中通信量增多时,链路因为数据量太大用而产生通信链路拥塞的现象.针对传统的多路径路由网络通信中,造成通信不畅的问题,提出一种基于粒子群优化的多路径路由负载均衡的算法,通过粒子群算法感知链路状态,提取多个链路性能指标,动态选择能够快速实现通信的最优路径,避免了重复选取权值和最小的路径通信造成的通信拥塞而带来的通信实时性不高的问题.仿真证明,粒子群优化的多路径路由负载均衡算法,能够保证选取合适的通信网络,完成实时通信,取得了满意的效果.     

基于虚拟网格的干扰避免多路径路由协议

由无线信道的广播特性造成的路径之间的并行多径干扰问题,已经成为无线多媒体传感器网络中使用多路径路由必须解决的首要问题。针对该问题,提出了一种虚拟网格的干扰避免多路径路由协议(IAMVG)。该协议通过把监测区域划分为虚拟网格的方式,预先选择互不干扰的网格,进而优先选择该网格内的簇头节点加入路由的方法,尽量拉开相互干扰链路之间的距离,保证多路径路由处于相互的干扰区域范围外或者尽可能降低干扰。仿真实验表明,IAMVG路由协议极大地减少了并行多径干扰,保证了较高的通信成功率及较低的端到端时延。     

一种基于分治策略的多路径Ad Hoc路由协议

在无线自组织网络(MANET)中,比起单路径路由协议,多路径路由协议提供了更好的可靠性、容错性、负载平衡等,并且提供较小的端对端延迟、提供较大的有效总带宽;但是,当网络规模较大、通信节点之间相距较远时,多路径路由协议的开销会很大,多路径的条数也减少.针对这一问题,提出了一种基于分治思想的多路径路由协议(DCMR).当通信节点之间必须经过的节点较多时,将这些节点划分为较小的节点集,对各个节点集分别进行路径查找及维护.模拟实验表明,该协议明显提高了路由寻径效率,减小了网络维护开销,并且实现简单,更具实用性.     

基于探测的多信道无线网状网机会路由算法

多信道无线网状网的性能在很大程度上依赖于信道分配和路由选择.现有的多信道无线网状网路由大多没有考虑信道之间的干扰问题,从而导致通信性能下降.针对这一问题,提出一种基于探测的多信道无线网状网机会路由(POR)算法.首先,根据干扰能量,选出最佳通信信道集来降低信道间的传榆干扰.在此基础上,采用探测方式计算路径期望传输时延,确定候选链路集并运用机会路由机制进行数据传输以最小化端到端的传输时延.实验结果表明,POR可以显著地降低平均端到端时延,提高数据包投递率,为数据传输提供实时性和可靠性保证.     

UWSNs中基于深度的抑制空洞路由优化算法

针对传统的水下无线传感器网络(UWSNs)的位置路由存在路由空洞问题,提出了基于深度的抑制空洞路由(DSVR)的UWSNs路由协议.DSVR协议通过融合跳数、物理距离和邻居数多个指标决策路由.为了提高通信可靠和缓解路由空洞,DSVR协议选择具有最小跳数路径、最少邻居数的节点作为下一跳转发节点.同时,DSVR协议利用定时器抑制冗余数据包.仿真结果表明:提出的DSVR协议能有效地提高数据包传递率,并降低端到端传输时延以及能耗.     

基于神经网络和节点梯度的VANET路由协议

基于车载自组织网络的特性,提出一种借助于梯度场的方法,并将神经网络应用于车载自组织网络进行下一跳节点选择的路由算法,以达到快速准确地传递数据包的目的.该算法利用节点的位置、速度等信息,计算节点的梯度值,并利用神经网络根据不同路段的条件调整梯度计算中各个参量的优先级,选择梯度值最大的节点作为下一跳节点.仿真结果表明,与城市场景下的贪婪边界无状态路由(GPSR,Greedy Perimeter Stateless Routing)和无线自组网按需平面距离矢量路由(AODV,Ad hoc On-Demand Distance Vector Routing)相比,基于神经网络和节点梯度的路由协议(NN-NGR,Neural Network and Node Gradient Routing)在数据包丢包率、数据包端到端平均时延方面具有较好的性能.     

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.