无线传感器网络的L EACH 算法的改进

无线传感器网络是监控远程环境的工具之一.由于能量和存储空间的限制,其路由协议必须维持较小的路由信息并尽可能的减少能量消耗.基于经典的LEACH路由算法,提出了改进:主要体现在对能量和簇头间距的考虑上.最后用Matlab对LEACH算法和改进后的算法进行仿真,证实改进后的算法在网络生存时间和簇负载平衡程度上比LEACH算法有了很大提高.     

一种无线传感器网络路由协议的研究与改进

无线传感器网络由许多具有低功率无线收发装置的传感器节点组成,能够有效地感知、采集和处理网络覆盖区域中的相关信息,并发送给远处的基站进一步处理。由于传感器节点能量有限,路由协议必须尽可能地减少能量消耗,延长网络生命周期。对经典的LEACH路由协议进行研究,并针对簇头节点和基站的通信方式提出改进,用M atlab平台下对LEACH算法和改进后的算法进行仿真分析,结果显示:改进后的算法在延长网络生命周期和减少能量消耗上比LEACH算法有了很大改善。     

无线传感器网络LEACH算法的改进

无线传感器网络是监控远程环境的工具之一,由于能量和存储空间的限制,其路由协议必须维持较小的路由信息并尽可能地减少能量消耗.基于经典的LEACH算法进行了改进,主要体现在对簇头选举的考虑上,把节点的剩余能量考虑到簇头的选举过程中去.最后对经典LEACH算法和改进后的算法进行仿真比较,证实改进后的算法很大程度上延长了网络的生存时间,同时减小了簇中节点的能量消耗.     

一种新的基于LEACH的WSN路由算法

研究无线传感器网络路由算法,无线传感器网络由能量有限的节点组成,因此高效节能的路由算法是无线传感器网络组网的基础.针对低功耗自适应分簇(LEACH)路由算法存在簇首节点选择不合理以及簇首节点与基站在远距离通信过程中能量消耗大的不足,提出了一种改进的LEACH路由算法.改进的算法在簇建立阶段的簇首选举过程中,引入节点剩余能量因素,且进行均匀分簇,有效地降低剩余能量较小和位置不佳节点成为簇首的可能性,均衡了网络的能量消耗,在簇稳定工作阶段,节点间的数据传输采用单跳和多跳相结合的通信方式,从而降低网络能耗.仿真结果表明,与传统的LEACH算法相比,改进的LEACH算法能量均衡性更好,并显著地延长了网络的存活时间.     

LEACH协议的簇头多跳（LEACH-M）改进算法

节能高效的实现路由转发是路由设计的一个关键点。总结了目前已有的无线传感器网络的传输路由模式,发现早先提出的LEACH协议虽是无线传感网中的低功耗自适应分层路由算法,但会造成簇头节点负载过重。成簇算法是传感器网络中减少能量消耗的一种关键技术。提出的是基于LEACH算法的多跳路由改进算法,并在考虑簇头最优个数的选择下,通过采用簇头之间的多跳算法达到减少能量消耗、延长传感网的寿命的目的。实验表明此方法有效。     

蚁群算法在LEACH路由协议中的应用

减少网络能量损失,增加网络的生成时间是无线传感网络的重要研究内容。LEACH是针对无线传感网络设计的低功耗自适应的路由算法。但是传统LEACH路由算法存在簇首开销过大、簇规模分布不均匀等问题。针对LEACH算法存在的缺点,从成簇方式和簇头路由拓扑提出改进方案,成簇半径随着距离Sink节点的增加而减小,簇首间采用蚁群算法进行路由优化。实验从网络节点存活的节点数目和节点的平均耗能两个指标对仿真结果进行评价,仿真结果显示改进算法网络的生存时间比传统结果提高了15％,节点平均能耗降低20％。改进算法可有效减少网络的总能量消耗,均衡网络的负载。     

无线传感器网络LEACH协议的研究与改进

在分析了无线传感器网络中分层路由LEACH算法的基础上,提出了一种新型选择簇首节点的方法,并通过matlab对改进后的LEACH算法进行了仿真,仿真结果显示改进后的LEACH算法在网络生命周期和网络能量消耗两方面比LEACH算法有很大的提高。     

一种基于LEAC日协议的分簇路由算法

低能自适应聚类路由协议(LEACH协议)是为无线传感器网络设计的一种低功耗自适应分层路由协议,具有延长网络生命时间的作用.为了均衡无线传感器网络节点的能耗,延长整个网络的生命周期,通过对LEACH协议的研究,对簇首的选取和簇首与Sink的通信机制进行优化,提出了一种改进的LEACH协议的分簇路由算法.通过Madab仿真实验证明,改进后的LEACH算法在网络生命周期和网络能量消耗等方面比LEACH算法有较大的提高.     

基于leach协议算法的改进与仿真

针对无线传感器网络中传感器能量有限的问题,从路由算法的角度出发,提出LEACH协议的低功耗改进方案。该文找到了使整个网络能量消耗最小的最优簇头数目P,改进LEACH协议中的随机簇头选举方式,同时给出了该算法的数学推导和进行了NS-2仿真实验。仿真实验的结果表明,改进的LEACH算法能够有效的减少传感器网络节点的能量消耗,最大限度的延长整个无线传感器网络的生命周期。     

三维固定分簇异构传感网络路由协议

基于高楼三维空间中家居监测的应用背景,提出了一种三维空间中LEACH路由协议的改进算法:三维固定分簇异构传感网络路由协议(3D-FHSR).在3D-FHSR中,使用了异构网络的方式让部分能量充裕的节点固定充当簇头节点,并且事先划分好簇的区域范围,这样减少了簇头选举时的能量消耗,同时增加了整个网络的能量.3D-FHSR还改进了LEACH协议的通信模式,减少簇间长距离通信的次数.仿真结果表明,3D-FHSR协议比LEACH协议更能延长网络的生命周期.     

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.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.